Initial work on APNG support

.cargo/config.toml

@@ -1,2 +0,0 @@
-[alias]
-xtask = "run --manifest-path xtask/Cargo.toml --"

.dockerignore

@@ -1,7 +0,0 @@
-.editorconfig
-.gitignore
-/.git/
-/.github/
-/.pre-commit-hooks.yaml
-/scripts/
-/target/

.editorconfig

@@ -1,11 +1,10 @@
 root = true
 
 [*]
-charset = utf-8
 end_of_line = lf
-indent_style = space
 insert_final_newline = true
-trim_trailing_whitespace = true
 
 [*.rs]
+charset = utf-8
+indent_style = space
 indent_size = 4

.gitattributes

@@ -1,2 +0,0 @@
-# Enforce Unix newlines
-* text=auto eol=lf

.github/dependabot.yml

@@ -1,24 +0,0 @@
-version: 2
-updates:
-  - package-ecosystem: "cargo"
-    directory: "/"
-    schedule:
-      interval: "weekly"
-    open-pull-requests-limit: 5
-    commit-message:
-      prefix: "chore"
-      include: "scope"
-    labels:
-      - "dependencies"
-      - "rust"
-    groups:
-      rust-dependencies:
-        patterns:
-          - "*"
-        update-types:
-          - "minor"
-          - "patch"
-  - package-ecosystem: "github-actions"
-    directory: "/"
-    schedule:
-      interval: "weekly"

.github/workflows/deploy.yml

@@ -1,138 +0,0 @@
-name: deploy
-
-on:
-  push:
-    tags:
-      - v*.*.*
-
-concurrency:
-  # If we ever end up with two concurrent jobs for releasing the same tag, the former should be cancelled
-  group: release-${{ github.ref }}
-  cancel-in-progress: true
-
-permissions:
-  actions: read
-  contents: write
-
-jobs:
-  deploy:
-    name: Deploy release
-
-    runs-on: ubuntu-latest
-    timeout-minutes: 30
-
-    # Prevent job from running on forks
-    if: ${{ !github.event.repository.fork }}
-
-    strategy:
-      # Execute one job at a time to avoid potential race conditions in the
-      # GitHub release management APIs. See:
-      # https://github.com/softprops/action-gh-release/issues/445#issuecomment-2407940052
-      max-parallel: 1
-      matrix:
-        target:
-          - x86_64-unknown-linux-gnu
-          - x86_64-unknown-linux-musl
-          - aarch64-unknown-linux-gnu
-          - aarch64-unknown-linux-musl
-          - x86_64-pc-windows-msvc
-          - i686-pc-windows-msvc
-          - x86_64-apple-darwin
-          - aarch64-apple-darwin
-
-    steps:
-      - name: Checkout source
-        uses: actions/checkout@v6
-
-      - name: Install Rust toolchain
-        uses: actions-rust-lang/setup-rust-toolchain@v1
-        with:
-          toolchain: nightly
-          cache-bin: false
-          cache-shared-key: cache
-
-      - name: Install cargo-deb
-        if: endsWith(matrix.target, '-linux-gnu')
-        uses: taiki-e/install-action@v2
-        with:
-          tool: cargo-deb
-
-      - name: Get the Oxipng version
-        id: oxipngMeta
-        run: >
-          echo "version=$(cargo metadata --format-version 1 --no-deps |
-          jq -r '.packages[] | select(.name == "oxipng").version')" >> "$GITHUB_OUTPUT"
-
-      - name: Retrieve ${{ matrix.target }} binary
-        uses: dawidd6/action-download-artifact@v21
-        with:
-          workflow: oxipng.yml
-          commit: ${{ github.sha }}
-          name: Oxipng binary (${{ matrix.target }})
-          path: target
-
-      - name: Generate up to date manual
-        run: scripts/manual.sh
-
-      - name: Build archives
-        working-directory: target
-        run: |
-          ARCHIVE_NAME="oxipng-${{ steps.oxipngMeta.outputs.version }}-${{ matrix.target }}"
-
-          mkdir "$ARCHIVE_NAME"
-          cp ../CHANGELOG.md ../README.md ../MANUAL.txt "$ARCHIVE_NAME"
-
-          case '${{ matrix.target }}' in
-            *-windows-*)
-              cp ../LICENSE "$ARCHIVE_NAME/LICENSE.txt"
-              cp oxipng.exe "$ARCHIVE_NAME"
-              zip "${ARCHIVE_NAME}.zip" "$ARCHIVE_NAME"/*;;
-            *)
-              cp ../LICENSE "$ARCHIVE_NAME"
-              cp oxipng "$ARCHIVE_NAME"
-              # Execute permissions are not stored in artifact files,
-              # so make the binary world-executable to meet user
-              # expectations set by preceding releases.
-              # Related issue:
-              # https://github.com/oxipng/oxipng/issues/575
-              chmod ugo+x "$ARCHIVE_NAME"/oxipng
-              tar -vczf "${ARCHIVE_NAME}.tar.gz" "$ARCHIVE_NAME"/*;;
-          esac
-
-      - name: Install AArch64 libc components
-        if: matrix.target == 'aarch64-unknown-linux-gnu'
-        run: |
-          sudo apt-get -yq update
-          # The shared libc AArch64 libraries are needed for cargo deb below
-          # to be able to infer package requirements with dpkg-shlibdeps
-          # properly
-          sudo apt-get -yq install libc6-arm64-cross libgcc-s1-arm64-cross
-
-      - name: Build Debian packages
-        if: endsWith(matrix.target, '-linux-gnu')
-        env:
-          # The *-arm64-cross packages above install AArch64 libraries in
-          # /usr/<arch>/lib instead of /usr/lib/<arch>, as expected by
-          # cargo-deb and dpkg-shlibdeps to find such shared libraries.
-          # Make both of them visible to such commands by adding that directory
-          # to the dynamic linker's library search path. See:
-          # - <https://man7.org/linux/man-pages/man1/dpkg-shlibdeps.1.html> ("Errors" section)
-          # - <https://github.com/kornelski/cargo-deb/issues/21>
-          LD_LIBRARY_PATH: /usr/aarch64-linux-gnu/lib
-        run: |
-          mkdir -p "target/${{ matrix.target }}/release"
-          mv target/oxipng "target/${{ matrix.target }}/release"
-          cargo deb --target "${{ matrix.target }}" --no-build --no-strip
-
-      - name: Create release notes
-        run: tail -n +3 CHANGELOG.md | sed -e '/^$/,$d' > RELEASE_NOTES.txt
-
-      - name: Create release
-        uses: softprops/action-gh-release@v3
-        with:
-          name: v${{ steps.oxipngMeta.outputs.version }}
-          body_path: RELEASE_NOTES.txt
-          files: |
-            target/*.zip
-            target/*.tar.gz
-            target/${{ matrix.target }}/debian/*.deb

.github/workflows/docker.yml

@@ -1,60 +0,0 @@
-name: docker
-on:
-  push:
-    branches:
-      - master
-    tags:
-      - v*.*.*
-  pull_request:
-    types:
-      - opened
-      - synchronize
-  workflow_dispatch:
-    inputs:
-      use_cache:
-        description: "Use build cache"
-        required: true
-        type: boolean
-        default: true
-
-concurrency:
-  # If we ever end up with two concurrent Docker build jobs for the same commit
-  # and same versioning context, the former should be cancelled
-  group: docker-${{ github.sha }}-${{ github.ref_type }}-${{ github.head_ref }}
-  cancel-in-progress: true
-
-jobs:
-  build:
-    uses: docker/github-builder/.github/workflows/build.yml@v1
-    permissions:
-      contents: read
-      packages: write
-      id-token: write
-      attestations: write
-    with:
-      output: image
-      platforms: linux/amd64,linux/arm64
-      push: ${{ github.event_name != 'pull_request' }}
-      cache: ${{ github.event_name != 'workflow_dispatch' || inputs.use_cache }}
-      # We don't sign the image because ghcr.io doesn't support OCI Referrers API yet, and the fallback relies on pushing new tags on each build
-      # https://github.com/docker/github-builder/issues/109#issuecomment-3885082486
-      # https://github.com/opencontainers/distribution-spec/blob/v1.1.0/spec.md#backwards-compatibility
-      sign: false
-      sbom: true
-      meta-images: ghcr.io/${{ github.repository }}
-      meta-tags: |
-        type=ref,event=branch
-        type=ref,event=pr
-        type=semver,pattern={{raw}}
-      set-meta-annotations: true
-      set-meta-labels: true
-      labels: |
-        org.opencontainers.image.title=Oxipng
-      annotations: |
-        org.opencontainers.image.title=Oxipng
-
-    secrets:
-      registry-auths: |
-        - registry: ghcr.io
-          username: ${{ github.actor }}
-          password: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/oxipng.yml

@@ -1,180 +0,0 @@
-name: oxipng
-
-on:
-  push:
-  pull_request:
-    types:
-      - opened
-      - synchronize
-  workflow_dispatch:
-
-concurrency:
-  # If we ever end up with two concurrent CI jobs for the same commit, the former should be cancelled
-  group: ci-${{ github.sha }}
-  cancel-in-progress: true
-
-jobs:
-  ci:
-    name: CI
-
-    runs-on: ${{ matrix.os }}
-    timeout-minutes: 60
-
-    # Prevent tags and in-repo PRs from triggering this workflow more than once for a commit
-    if: github.ref_type != 'tag' && (github.event_name != 'pull_request' || github.event.pull_request.head.repo.fork)
-
-    strategy:
-      fail-fast: false
-      matrix:
-        target:
-          - x86_64-unknown-linux-gnu
-          - x86_64-unknown-linux-musl
-          - aarch64-unknown-linux-gnu
-          - aarch64-unknown-linux-musl
-          - x86_64-pc-windows-msvc
-          - i686-pc-windows-msvc
-          - x86_64-apple-darwin
-          - aarch64-apple-darwin
-
-        include:
-          - target: x86_64-unknown-linux-gnu
-            os: ubuntu-24.04
-            target-apt-arch: amd64
-          - target: x86_64-unknown-linux-musl
-            os: ubuntu-24.04
-            target-apt-arch: amd64
-          - target: aarch64-unknown-linux-gnu
-            os: ubuntu-24.04-arm
-            target-apt-arch: arm64
-          - target: aarch64-unknown-linux-musl
-            os: ubuntu-24.04-arm
-            target-apt-arch: arm64
-          - target: x86_64-pc-windows-msvc
-            os: windows-latest
-          - target: i686-pc-windows-msvc
-            os: windows-latest
-          - target: x86_64-apple-darwin
-            os: macos-15
-          - target: aarch64-apple-darwin
-            os: macos-15
-
-    env:
-      CARGO_BUILD_TARGET: ${{ matrix.target }}
-
-    steps:
-      - name: Checkout source
-        uses: actions/checkout@v6
-        with:
-          persist-credentials: false
-
-      - name: Install musl development files
-        if: endsWith(matrix.target, '-musl')
-        run: |
-          sudo apt-get -yq update
-          sudo apt-get -yq install musl-tools musl-dev:${{ matrix.target-apt-arch }}
-
-      - name: Install Rust toolchain
-        uses: actions-rust-lang/setup-rust-toolchain@v1
-        with:
-          toolchain: nightly
-          target: ${{ env.CARGO_BUILD_TARGET }}
-          components: clippy, rustfmt, rust-src
-          cache-bin: false
-          cache-shared-key: cache
-
-      - name: Install nextest
-        uses: taiki-e/install-action@nextest
-
-      - name: Install cargo-hack
-        if: matrix.target == 'x86_64-unknown-linux-gnu'
-        uses: taiki-e/install-action@cargo-hack
-
-      - name: Install clippy-sarif
-        if: matrix.target == 'x86_64-unknown-linux-gnu'
-        uses: taiki-e/install-action@v2
-        with:
-          tool: clippy-sarif
-
-      - name: Install sarif-fmt
-        if: matrix.target == 'x86_64-unknown-linux-gnu'
-        uses: taiki-e/install-action@v2
-        with:
-          tool: sarif-fmt
-
-      - name: Run rustfmt
-        if: matrix.target == 'x86_64-unknown-linux-gnu'
-        run: cargo fmt --check
-
-      - name: Run Clippy for all feature combinations
-        if: matrix.target == 'x86_64-unknown-linux-gnu'
-        run: >
-          set -o pipefail;
-          cargo hack clippy --no-deps --all-targets --feature-powerset \
-            --exclude-features sanity-checks,system-libdeflate \
-            --message-format=json -- -D warnings \
-          | clippy-sarif
-          | tee clippy-results.sarif
-          | sarif-fmt
-
-      - name: Run tests
-        run: |
-          cargo nextest run --release --features sanity-checks
-          cargo test --doc --release --features sanity-checks
-
-      - name: Build benchmarks
-        run: cargo bench --no-run
-
-      - name: Build docs
-        if: matrix.target == 'x86_64-unknown-linux-gnu'
-        run: cargo doc --release --no-deps
-
-      - name: Build CLI binary
-        run: cargo build --release -Zbuild-std
-        env:
-          RUSTFLAGS: "-Zlocation-detail=none -Zunstable-options -Cpanic=immediate-abort"
-
-      - name: Upload CLI binary as artifact
-        uses: actions/upload-artifact@v7
-        with:
-          name: Oxipng binary (${{ matrix.target }})
-          path: |
-            target/${{ env.CARGO_BUILD_TARGET }}/release/oxipng
-            target/${{ env.CARGO_BUILD_TARGET }}/release/oxipng.exe
-
-      - name: Upload analysis results to GitHub
-        uses: github/codeql-action/upload-sarif@v4
-        if: always() && matrix.target == 'x86_64-unknown-linux-gnu'
-        continue-on-error: true
-        with:
-          sarif_file: clippy-results.sarif
-          category: clippy
-
-  msrv-check:
-    name: MSRV check
-
-    runs-on: ubuntu-latest
-    timeout-minutes: 30
-
-    # Prevent tags and in-repo PRs from triggering this workflow more than once for a commit
-    if: github.ref_type != 'tag' && (github.event_name != 'pull_request' || github.event.pull_request.head.repo.fork)
-
-    steps:
-      - name: Checkout source
-        uses: actions/checkout@v6
-        with:
-          persist-credentials: false
-
-      - name: Install MSRV Rust toolchain
-        uses: actions-rust-lang/setup-rust-toolchain@v1
-        with:
-          toolchain: 1.85.1
-          cache-bin: false
-          cache-shared-key: cache
-
-      - name: Install nextest
-        uses: taiki-e/install-action@nextest
-
-      - name: Run tests
-        run: |
-          cargo nextest run --release --features sanity-checks
-          cargo test --doc --release --features sanity-checks

.gitignore

@@ -1,6 +1,7 @@
-.DS_Store
+target
 *.bk
+.DS_Store
 *.out.png
-/.idea/
+/.idea
-/node_modules/
+/.vscode
-/target/
+/node_modules

.pre-commit-hooks.yaml

@@ -1,7 +0,0 @@
--   id: oxipng
-    name: oxipng
-    description: 'Multithreaded PNG optimizer written in Rust.'
-    entry: oxipng
-    language: rust
-    types: [png]
-    require_serial: true

.travis.yml

@@ -0,0 +1,49 @@
+language: rust
+
+env:
+  global:
+    - PROJECT_NAME=oxipng
+
+matrix:
+  include:
+    - os: osx
+      rust: stable
+      env: TARGET=x86_64-apple-darwin
+      cache: cargo
+    - os: linux
+      rust: 1.27.0
+      env: TARGET=x86_64-unknown-linux-gnu
+      cache: cargo
+    - os: linux
+      rust: stable
+      env: TARGET=x86_64-unknown-linux-gnu
+      cache: cargo
+    - os: linux
+      rust: beta
+      env: TARGET=x86_64-unknown-linux-gnu
+      cache: cargo
+    - os: linux
+      rust: nightly
+      env: TARGET=x86_64-unknown-linux-gnu
+      cache: cargo
+  allow_failures:
+    - rust: beta
+    - rust: nightly
+
+deploy:
+  provider: releases
+  api_key:
+    secure: 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
+  file_glob: true
+  file: ${PROJECT_NAME}-${TRAVIS_TAG}-${TARGET}.*
+  # don't delete the artifacts from previous phases
+  skip_cleanup: true
+  # deploy when a new tag is pushed
+  on:
+    # channel to use to produce the release artifacts
+    condition: $TRAVIS_RUST_VERSION = stable
+    tags: true
+
+notifications:
+  email:
+    on_success: never

CHANGELOG.md

@@ -1,587 +1,265 @@
-## Version 10.1.1
-
-- [Performance] Improve Bigrams performance, giving notably faster results at lower levels.
-- [Improvement] Change `--np` flag to also prevent conversion to indexed from other color types.
-- [Improvement] Improve support for recompressing ICC profiles with high compression ratios.
-- [Misc] Add warning when `--ziwi` exceeds `--zi`.
-- [Build] Further reduce size of binaries.
-
-## Version 10.1.0
-
-- [Feature] Add `--json` option for machine-readable output.
-- [Improvement] New default output with file counter and summary. (Use an extra `-v` flag to get the same output as before.)
-- [Bugfix] Fix fast mode sometimes giving suboptimal results for small, indexed images.
-
-## Version 10.0.0
-
-- [Breaking] CLI: Change short zopfli flag from `-Z` to `-z`.
-- [Breaking] CLI: Change `--pretend`/`-P` to `--dry-run`/`-d`.
-- [Breaking] CLI: Change `--interlace` options from `1`/`0` to `on`/`off`.
-- [Breaking] API: Change `Options.interlace: Option<Interlacing>` to `Options.interlace: Option<bool>`.
-- [Breaking] API: Change `Options.filter: IndexSet<RowFilter>` to `Options.filters: IndexSet<FilterStrategy>`.
-- [Breaking] API: Change `Options.deflate: Deflaters` to `Options.deflater: Deflater`.
-- [Breaking] API: Change `Deflaters::Zopfli { .. }` to `Deflater::Zopfli(ZopfliOptions { .. })`.
-- [Breaking] API: Change `optimize()` to return `(usize, usize)`, with original and optimized sizes.
-- [Feature] Allow zopfli iterations higher than 255.
-- [Feature] Add `--ziwi` option for zopfli iterations without improvement.
-- [Feature] Add `--max-raw-size` option to skip images that are too large.
-- [Feature] Add `--brute-level` and `--brute-lines` options for advanced control of Brute filter.
-- [Improvement] Reduce memory usage for `fast` mode.
-- [Improvement] Slightly improve compression with Brute filter at levels 5 and 6.
-- [Misc] Change `--preserve` option to no longer preserve last access time.
-- [Misc] Make help output colored.
-
-## Version 9.1.5
-
-- [Feature] Add `--sequential` option to process files sequentially rather than in parallel.
-- [Performance] Update to latest Zopfli with greatly improved performance.
-- [Improvement] Reduce memory usage.
-- [Bugfix] Correct handling of grayscale conversion when ICC profile is present.
-
-## Version 9.1.4
-
-- [Improvement] Improve optimization of APNG files (reductions still not supported yet).
-- [Improvement] Improve reductions for small images and ensure consistent results for repeat runs.
-- [Build] Add feature `system-libdeflate` to use the system-installed version of libdeflate.
-- [Misc] Strip C2PA metadata by default.
-
-## Version 9.1.3
-
-- [Feature] Add `--zi` option to control the number of Zopfli iterations.
-- [Improvement] Allow setting compression level to 0.
-- [Performance] Improve filtering performance for some images.
-- [Build] Move man page generation to an xtask.
-
-## Version 9.1.2
-
-- [Bugfix] Fix `--nx` still applying deinterlacing by default.
-- [Bugfix] Fix wildcard matching being case-sensitive on Windows.
-- [Bugfix] Fix optimized APNGs not being compatible with some programs.
-- [Build] Fix feature `sanity-checks` not working without `parallel`.
-- [Misc] Resolve ambiguity between optional dependencies and crate features.
-
-## Version 9.1.1
-
-- [Build] Change man page generation path to resolve issue with cargo publish.
-
-## Version 9.1.0
-
-- [Improvement] Add `--keep display` equivalent to `--strip safe`.
-- [Improvement] Add modified zeng palette sorting method, improving optimization of indexed images.
-- [Improvement] If only one filter is specified, guarantee to only use this one.
-- [Improvement] Evaluate low-depth indexed even if low-depth grayscale was already achieved.
-- [Bugfix] Fix battiato palette sorting method not being used if the input was not already indexed.
-- [Bugfix] Fix rare crash caused by a truncated palette.
-- [Build] Reduce size of binaries.
-- [Build] Add man page generation.
-- [Build] Publish deb archives for Linux.
-- [Misc] Bump minimum Rust version to 1.74.0.
-
-## Version 9.0.0
-
-- [Breaking] Remove `--backup` option. Use `--out` or `--dir` to preserve existing files.
-- [Breaking] Remove `--check` option. Use `--nx --nz` to perform a non-optimizing run.
-- [Breaking] API: Replace `pretend` option with `OutFile::None`.
-- [Breaking] API: Move `preserve_attrs` into `OutFile::Path`.
-- [Breaking] Default to removing interlacing. Use `-i keep` to retain existing interlacing.
-- [Feature] Add Raw API for creating optimised PNGs from raw image data.
-- [Feature] Add basic support for APNG files.
-- [Feature] Add `--scale16` option to forcibly reduce 16-bit images to 8-bit.
-- [Improvement] Process multiple files in parallel.
-- [Improvement] Improve reductions, particularly for indexed or very small images.
-- [Improvement] Improve compression with latest version of libdeflate.
-- [Improvement] Recompress iCCP chunks.
-- [Improvement] Change recursive mode to only process .png/.apng files.
-- [Improvement] Add support for glob patterns in quotes on Windows.
-- [Improvement] Quieter default output logging, with multiple levels of verbosity.
-- [Bugfix] Fix deadlock when using oxipng within an existing Rayon thread pool.
-- [Bugfix] Fix early abort in recursive mode when a read error occurred.
-- [Bugfix] Fix losing aux chunks when there's more than one of the same type.
-- [Bugfix] Fix sometimes writing output even when it was larger.
-- [Misc] Revamp CI workflow to upload artifacts and generate binaries for additional architectures.
-- [Misc] Bump minimum Rust version to 1.66.0.
-
-## Version 8.0.0
-
-- [Breaking] Revamp alpha optimization
-- [Bugfix] Fix grayscale depth reduction with tRNS pixel
-- [Bugfix] Fix fast mode with zopfli
-- [Improvement] Tweaks to interlacing and format display
-- [Improvement] Ability to reduce alpha channel to tRNS pixel
-- [Improvement] Performance improvements to colorspace reduction
-- [Misc] Disable image validation in release mode, as it is deemed no longer necessary
-
-## Version 7.0.0
-
-- [Breaking] Switch to libdeflater as the default
-- [Breaking] Rebalance presets
-- [Breaking] Update safe headers to remove
-- [Breaking] Bump minimum Rust version to 1.61.0
-- [Feature] Introduce new filter strategies
-- [Feature] Allow setting libdeflate compression level
-- [Feature] Add optional dockerization
-- [Improvement] Improve alpha reductions
-- [Improvement] Fast deinterlace for 8-bit
-- [Improvement] Refactor heuristics for fast filter evaluation
-- [Improvement] Improve file size reduction further
-- [Bugfix] Avoid printing output bytes on decompress error
-- [Bugfix] Fix compression level 0
-- [Bugfix] Fix directional alpha reductions
-- [Bugfix] Fix edge cases in palette reduction
-
-### Version 6.0.1
-
-- [Bugfix] Fix an issue where Zopfli mode could generate corrupt images
-
-### Version 6.0.0
-
-- [Breaking] Bump minimum Rust version to 1.57.0
-- [Feature] Add `--check`/`-c` CLI option
-- [Security] Update stderrlog to 0.5.2 (Fixes RUSTSEC-2022-0006)
-- [Security] Remove chrono as a transitive dependency (Fixes RUSTSEC-2020-0159)
-- [Misc] Bump `clap` to 3.2
-- [Misc] Bump `zopfli` to 0.7
-- [Misc] Bump `libdeflater` to 0.10
-- [Misc] Remove `byteorder` dependency in favor of stdlib functions
-- [Misc] Bump `image` to 0.24
-- [Misc] Bump `crc` to 3.0
-- [Misc] Bump `miniz_oxide` to 0.6
-- [Misc] Update to Rust edition 2021
-- [Misc] Various internal improvements
-
-### Version 5.0.1
-
-- [Bugfix] Fix an issue where -o5 and -o6 were not testing all options
-- [Misc] Bump miniz_oxide to 0.5
-
-### Version 5.0.0
-
-- [Breaking] Bump minimum Rust version to 1.46.0
-- [Bugfix] Avoid many panics that may occur on broken files
-- [Bugfix] Fix race condition that may cause tests to fail
-- [Performance] Optimizations to unfiltering and copying
-- [Feature] Add `--ng` option to skip grayscale reduction
-- [Feature] Also preserve timestamps when using `--preserve`
-- [Misc] Bump `crc` to 2.x
-
-### Version 4.0.3
-
-- Bump itertools to 0.10.x
-- Temporarily disable i686 releases, which were failing due to an odd linker issue,
-  so that at least amd64 builds will publish successfully
-  - This only relates to the releases published on Github. You can still manually compile oxipng for any platform.
-
-### Version 4.0.2
-
-- Includes another update to libdeflater that improves support for targets
-  without a C stdlib, like wasm32.
-
-### Version 4.0.1
-
-- Includes an update to libdeflater that improves support for targets
-  without a C stdlib, like wasm32.
-
-### Version 4.0.0
-
-- [Breaking] Bump minimum Rust version to 1.45.0
-- [Feature] Make `libdeflater` and `zopfli` optional for API users
-- [Bugfix] Fix cloudflare-zlib on aarch64 CPUs
-- [Bugfix] Don't exit on finding a non-PNG file when crawling recursively
-- [Bugfix] Make `rayon` truly optional
-- Various internal improvements
-
-### Version 3.0.1
-
-- [Bugfix] Re-add `--force` flag to CLI
-  - This was accidentally removed somehow
-- Many non-breaking dependency version bumps
-
-### Version 3.0.0
-
-- [Breaking] Bump minimum Rust version to 1.41.0
-- [Breaking] Use IndexMap/IndexSet to provide more consistent performance ([#202](https://github.com/oxipng/oxipng/pull/202))
-  - This changes some public-facing types.
-    `IndexMap` and `IndexSet` are reexported
-    at the crate root to aid migration.
-- [Breaking] Remove fields from the `Options` struct which were never used ([#211](https://github.com/oxipng/oxipng/pull/211/files#diff-b4aea3e418ccdb71239b96952d9cddb6L217), [#212](https://github.com/oxipng/oxipng/pull/212/files#diff-b4aea3e418ccdb71239b96952d9cddb6L134))
-- [Breaking] Refactor zlib-specific options in the `Options` struct ([#210](https://github.com/oxipng/oxipng/pull/210/files))
-- [Feature] Add libdeflater as an option ([#203](https://github.com/oxipng/oxipng/pull/203))
-- [Feature] Use standard `log` library ([#218](https://github.com/oxipng/oxipng/pull/218))
-- [Feature] Add `-o max` setting which will always reference the highest compression preset ([#224](https://github.com/oxipng/oxipng/pull/224))
-- [Deprecated] `-o 4` was found to be equivalent to `-o 3` and is deprecated.
-  It will likely be removed in a future release.
-  For now it remains equivalent to `-o 3`. ([#224](https://github.com/oxipng/oxipng/pull/224))
-- [Bugfix] Ensure output is deterministic ([#199](https://github.com/oxipng/oxipng/pull/199))
-- Update `image` crate to 0.23
-- Update `itertools` crate to 0.9
-- Various performance and internal improvements
-
-### Version 2.3.0
-
-- Allow disabling all alpha optimizations ([#181](https://github.com/oxipng/oxipng/pull/181))
-- Fix interlacing issues on tiny images ([#182](https://github.com/oxipng/oxipng/pull/182))
-- Reduce memory usage in filtering ([#191](https://github.com/oxipng/oxipng/pull/191))
-- Implement palette sorting to improve compression ([#193](https://github.com/oxipng/oxipng/pull/193))
-- Disable alpha optimizations by default ([#187](https://github.com/oxipng/oxipng/pull/187))
-- Add support for WASM ([#194](https://github.com/oxipng/oxipng/pull/194))
-
-### Version 2.2.2
-
-- Fix grayscale bit-depth reduction ([#171](https://github.com/oxipng/oxipng/pull/171))
-- Fix typos and incorrect log message ([#172](https://github.com/oxipng/oxipng/pull/172))
-- Make metadata order deterministic ([#174](https://github.com/oxipng/oxipng/pull/174))
-- Fix 32-bit builds ([#176](https://github.com/oxipng/oxipng/pull/176))
-- Enable LTO in release builds ([#177](https://github.com/oxipng/oxipng/pull/177))
-- Use deterministic compression strategy ([#179](https://github.com/oxipng/oxipng/pull/179))
-- Fix decoding interlaced images with height or width <= 2 ([#175](https://github.com/oxipng/oxipng/pull/175))
-- Preallocate memory in reduced_alpha_to_up ([#180](https://github.com/oxipng/oxipng/pull/180))
-- Update `bit-vec` crate to 0.6
-
-### Version 2.2.1
-
-- Fix compression of very large files ([#167](https://github.com/oxipng/oxipng/pull/167)) ([#168](https://github.com/oxipng/oxipng/pull/168))
-
-### Version 2.2.0
-
-- Various internal improvements ([#154](https://github.com/oxipng/oxipng/pull/154)) ([#158](https://github.com/oxipng/oxipng/pull/158)) ([#160](https://github.com/oxipng/oxipng/pull/160)) ([#161](https://github.com/oxipng/oxipng/pull/161)) ([#162](https://github.com/oxipng/oxipng/pull/162)) ([#163](https://github.com/oxipng/oxipng/pull/163))
-- Update `image` crate to 0.21.0
-- Update `itertools` crate to 0.8.0
-- Update `zopfli` crate to 0.4.0
-- Use Rust edition 2018
-- Bump minimum required Rust version to 1.31.0
-
-### Version 2.1.8
-
-- Fix non-standard sBIT headers in other code locations ([#153](https://github.com/oxipng/oxipng/issues/153))
-
-### Version 2.1.7
-
-- 80x faster palette reduction ([#150](https://github.com/oxipng/oxipng/pull/150))
-- Optimize RGB to palette conversion ([#148](https://github.com/oxipng/oxipng/pull/148))
-- Various microoptimizations ([#146](https://github.com/oxipng/oxipng/pull/146))
-- Introduce third-party safe wrapper around cloudflare-zlib ([#149](https://github.com/oxipng/oxipng/pull/149))
-
-### Version 2.1.6
-
-- Identify and drop useless sRGB profiles ([#143](https://github.com/oxipng/oxipng/pull/143))
-- Alpha heuristic improvements ([#144](https://github.com/oxipng/oxipng/pull/144))
-- Bump `miniz_oxide` and `cloudflare-zlib-sys` to 0.2.0
-
 ### Version 2.1.5
-
+ - Fix issue where some images will incorrectly reduce bit depth ([#140](https://github.com/shssoichiro/oxipng/issues/140))
-- Fix issue where some images will incorrectly reduce bit depth ([#140](https://github.com/oxipng/oxipng/issues/140))
 
 ### Version 2.1.4
-
+ - Bump `image` crate to 0.20.0
-- Bump `image` crate to 0.20.0
 
 ### Version 2.1.3
-
+ - Fix i686 builds
-- Fix i686 builds
+ - Performance improvements
-- Performance improvements
 
 ### Version 2.1.2
-
+ - Fix issue with PNG to Indexed reduction on images with transparency pixel ([#129](https://github.com/shssoichiro/oxipng/issues/129))
-- Fix issue with PNG to Indexed reduction on images with transparency pixel ([#129](https://github.com/oxipng/oxipng/issues/129))
 
 ### Version 2.1.1
-
+ - More fixes for alpha optimization on interlaced images ([#133](https://github.com/shssoichiro/oxipng/issues/133))
-- More fixes for alpha optimization on interlaced images ([#133](https://github.com/oxipng/oxipng/issues/133))
 
 ### Version 2.1.0
-
+ - [SEMVER_MINOR] Bump minimum Rust version to 1.27.0
-- [SEMVER_MINOR] Bump minimum Rust version to 1.27.0
+ - [SEMVER_MINOR] Reenable faster Cloudflare zlib compression on platforms that support it
-- [SEMVER_MINOR] Reenable faster Cloudflare zlib compression on platforms that support it
+ - Fix memory leak with Cloudflare zlib ([#126](https://github.com/shssoichiro/oxipng/issues/126))
-- Fix memory leak with Cloudflare zlib ([#126](https://github.com/oxipng/oxipng/issues/126))
+ - Minor fixes and cleanup 
-- Minor fixes and cleanup
 
 ### Version 2.0.2
-
+ - Fix an issue in alpha optimization on interlaced images ([#113](https://github.com/shssoichiro/oxipng/issues/113))
-- Fix an issue in alpha optimization on interlaced images ([#113](https://github.com/oxipng/oxipng/issues/113))
 
 ### Version 2.0.1
-
+ - Revert making Cloudflare zlib the default, as it introduced a major memory leak. It will be put back behind a feature flag, and reenabled when the issue is fixed.
-- Revert making Cloudflare zlib the default, as it introduced a major memory leak. It will be put back behind a feature flag, and reenabled when the issue is fixed.
+ - Revert minimum Rust version to 1.24.0
-- Revert minimum Rust version to 1.24.0
 
 ### Version 2.0.0
-
+ - [SEMVER_MAJOR] Make PngError a proper Error enum
-- [SEMVER_MAJOR] Make PngError a proper Error enum
+ - [SEMVER_MINOR] Bump minimum Rust version to 1.27.0
-- [SEMVER_MINOR] Bump minimum Rust version to 1.27.0
+ - [SEMVER_MINOR] Make Rayon an optional dependency (enabled by default)
-- [SEMVER_MINOR] Make Rayon an optional dependency (enabled by default)
+ - [SEMVER_MINOR] Option to limit wall clock time spent in optimization trials
-- [SEMVER_MINOR] Option to limit wall clock time spent in optimization trials
+ - [SEMVER_MINOR] `--keep` option (works similar to `--strip`, but takes a comma-separated list of headers to keep, and removes all other non-critical headers)
-- [SEMVER_MINOR] `--keep` option (works similar to `--strip`, but takes a comma-separated list of headers to keep, and removes all other non-critical headers)
+ - Use faster Cloudflare zlib compression on platforms that support it
-- Use faster Cloudflare zlib compression on platforms that support it
+ - Allow specifying more than 2 filter types via the CLI
-- Allow specifying more than 2 filter types via the CLI
+ - Avoid double glob processing on unix
-- Avoid double glob processing on unix
+ - Fix reading from stdin
-- Fix reading from stdin
+ - Cleanup help text
-- Cleanup help text
+ - Various performance improvements
-- Various performance improvements
 
 ### Version 1.0.4
-
+ - Bump `image` to 0.19.0
-- Bump `image` to 0.19.0
+ - Bump `bit-vec` to 0.5.0
-- Bump `bit-vec` to 0.5.0
+ - Bump `regex` to 1.0.0
-- Bump `regex` to 1.0.0
 
 ### Version 1.0.3
-
+ - Bump dependencies
-- Bump dependencies
 
 ### Version 1.0.2
-
+ - Fix a change that breaks Itertools::flatten with recent Rust nightlies
-- Fix a change that breaks Itertools::flatten with recent Rust nightlies
 
 ### Version 1.0.1
-
+ - Bump rayon to 1.0 ([#99](https://github.com/shssoichiro/oxipng/pull/99) @cuviper)
-- Bump rayon to 1.0 ([#99](https://github.com/oxipng/oxipng/pull/99) @cuviper)
+ - Bump minor versions of other dependencies for binary distribution
-- Bump minor versions of other dependencies for binary distribution
 
 ### Version 1.0.0
-
+ - Remove the C dependency on miniz, and replace it with a Rust version ([#57](https://github.com/shssoichiro/oxipng/issues/57))
-- Remove the C dependency on miniz, and replace it with a Rust version ([#57](https://github.com/oxipng/oxipng/issues/57))
+    - This improves decompression speed by 15%. Compression speed is not affected.
-  - This improves decompression speed by 15%. Compression speed is not affected.
+    - [SEMVER_MAJOR] This also obsoletes the `-zm` command line option and the `memory` key on the `Options` struct.
-  - [SEMVER_MAJOR] This also obsoletes the `-zm` command line option and the `memory` key on the `Options` struct.
+    - Presets will be updated automatically. This means that presets 3 and higher will run significantly more quickly.
-  - Presets will be updated automatically. This means that presets 3 and higher will run significantly more quickly.
+ - [SEMVER_MAJOR] Adjust the presets, now that `-zm` is no longer an option.
-- [SEMVER_MAJOR] Adjust the presets, now that `-zm` is no longer an option.
+    - `-o3` now tests all filter types. This will result in 50% more trials than before, but may give up to 10% more compression gain.
-  - `-o3` now tests all filter types. This will result in 50% more trials than before, but may give up to 10% more compression gain.
+    - `-o4` and higher now test all alpha optimization types. This adds 5 trials specific to the alpha channel. Only transparent images are affected.
-  - `-o4` and higher now test all alpha optimization types. This adds 5 trials specific to the alpha channel. Only transparent images are affected.
+ - Implement unix-specific permissions copying for `-p` option
-- Implement unix-specific permissions copying for `-p` option
+ - Performance optimizations
-- Performance optimizations
+ - Refactor of internal code 
-- Refactor of internal code
 
 ### Version 0.19.0
-
+ - [SEMVER_MAJOR] Default to overwriting the input file if `out_file` is not set.
-- [SEMVER_MAJOR] Default to overwriting the input file if `out_file` is not set.
+ This does not affect the CLI, but with the library, it was easy to forget to set the `out_file`,
-  This does not affect the CLI, but with the library, it was easy to forget to set the `out_file`,
+ and there was no warning that no output file would be written.
-  and there was no warning that no output file would be written.
+ - Bump dependencies, reduces binary size by a considerable amount
-- Bump dependencies, reduces binary size by a considerable amount
+ - Hide all modules from documentation, and only export the specific structures that should be public.
-- Hide all modules from documentation, and only export the specific structures that should be public.
+ Previously there were too many implementation details made public. The modules are still public for the purposes of our integration tests,
-  Previously there were too many implementation details made public. The modules are still public for the purposes of our integration tests,
+ but we strongly advise against using undocumented modules. These may become private in the future.
-  but we strongly advise against using undocumented modules. These may become private in the future.
+ - Internal refactoring and code cleanup
-- Internal refactoring and code cleanup
+ - Fix an error message that was displaying the wrong file path
-- Fix an error message that was displaying the wrong file path
+ - Fix an issue where the output file would not be written if the input was already optimized,
-- Fix an issue where the output file would not be written if the input was already optimized,
+ even if the output path was different from the input path
-  even if the output path was different from the input path
 
 ### Version 0.18.3
-
+ - Return exit code of 1 if an error occurred while processing a file using the CLI app ([#93](https://github.com/shssoichiro/oxipng/issues/93))
-- Return exit code of 1 if an error occurred while processing a file using the CLI app ([#93](https://github.com/oxipng/oxipng/issues/93))
 
 ### Version 0.18.2
-
+ - Bump `image` to 0.18
-- Bump `image` to 0.18
+ - Fix unfiltering of scan lines in interlaced images ([#92](https://github.com/shssoichiro/oxipng/issues/92))
-- Fix unfiltering of scan lines in interlaced images ([#92](https://github.com/oxipng/oxipng/issues/92))
 
 ### Version 0.18.1
-
+ - Bump `rayon` to 0.9
-- Bump `rayon` to 0.9
+ - Fix failure to optimize on certain grayscale images ([#89](https://github.com/shssoichiro/oxipng/issues/89))
-- Fix failure to optimize on certain grayscale images ([#89](https://github.com/oxipng/oxipng/issues/89))
 
 ### Version 0.18.0
-
+ - Bump `itertools` to 0.7
-- Bump `itertools` to 0.7
+ - Bump `image` to 0.17
-- Bump `image` to 0.17
+ - [SEMVER_MAJOR] Bump minimum rustc version to 1.20.0
-- [SEMVER_MAJOR] Bump minimum rustc version to 1.20.0
+ - Fix parsing of glob paths on Windows ([#90](https://github.com/shssoichiro/oxipng/issues/90))
-- Fix parsing of glob paths on Windows ([#90](https://github.com/oxipng/oxipng/issues/90))
 
 ### Version 0.17.2
-
+ - Bump `image` to 0.16
-- Bump `image` to 0.16
+ - Quickly pass over files that do not have a PNG header ([#85](https://github.com/shssoichiro/oxipng/issues/85) @emielbeinema)
-- Quickly pass over files that do not have a PNG header ([#85](https://github.com/oxipng/oxipng/issues/85) @emielbeinema)
+ - Return an error instead of crashing on APNG files ([#83](https://github.com/shssoichiro/oxipng/issues/83) @emielbeinema)
-- Return an error instead of crashing on APNG files ([#83](https://github.com/oxipng/oxipng/issues/83) @emielbeinema)
 
 ### Version 0.17.1
-
+ - Remove VC++ download requirement for Windows users
-- Remove VC++ download requirement for Windows users
 
 ### Version 0.17.0
-
+ - [SEMVER_MAJOR] Bump minimum required rustc version to 1.19.0
-- [SEMVER_MAJOR] Bump minimum required rustc version to 1.19.0
+ - [SEMVER_MINOR] Oxipng will now, by default, attempt to change all transparent pixels to `rgba(0, 0, 0, 0)` to improve compression.
-- [SEMVER_MINOR] Oxipng will now, by default, attempt to change all transparent pixels to `rgba(0, 0, 0, 0)` to improve compression.
+    It does fast trials with filters 0 and 5 to see if this is an improvement over
-  It does fast trials with filters 0 and 5 to see if this is an improvement over
+    the existing alpha channel.
-  the existing alpha channel.
+ - [SEMVER_MINOR] Add a `-a` option to the command line (`alphas` in the struct) which enables 6 different
-- [SEMVER_MINOR] Add a `-a` option to the command line (`alphas` in the struct) which enables 6 different
+    trials for optimizing the alpha channel, using the previously mentioned fast heuristic.
-  trials for optimizing the alpha channel, using the previously mentioned fast heuristic.
+    This option will make optimization of images with transparency somewhat slower,
-  This option will make optimization of images with transparency somewhat slower,
+    but may improve compression.
-  but may improve compression.
+ - Fixed a bug in reducing palettes for images with bit depth of two ([#80](https://github.com/shssoichiro/oxipng/issues/80))
-- Fixed a bug in reducing palettes for images with bit depth of two ([#80](https://github.com/oxipng/oxipng/issues/80))
+ - Fixed another bug in reducing palettes for images with bit depth less than eight ([#82](https://github.com/shssoichiro/oxipng/issues/82))
-- Fixed another bug in reducing palettes for images with bit depth less than eight ([#82](https://github.com/oxipng/oxipng/issues/82))
+ - Code cleanup
-- Code cleanup
+ - Bump `image` to 0.15
-- Bump `image` to 0.15
 
 ### Version 0.16.3
-
+ - Fix command-line help text ([#70](https://github.com/shssoichiro/oxipng/issues/70))
-- Fix command-line help text ([#70](https://github.com/oxipng/oxipng/issues/70))
 
 ### Version 0.16.2
-
+ - Publicly export `error` module
-- Publicly export `error` module
 
 ### Version 0.16.1
-
+ - Fix rayon's breaking changes that they made in a point release
-- Fix rayon's breaking changes that they made in a point release
 
 ### Version 0.16.0
-
+ - [SEMVER_MAJOR] Bump minimum rustc version to 1.17.0
-- [SEMVER_MAJOR] Bump minimum rustc version to 1.17.0
+ - Bump `image` to 0.14
-- Bump `image` to 0.14
+ - Bump `rayon` to 0.8
-- Bump `rayon` to 0.8
 
 ### Version 0.15.2
-
+ - Bump `image` to 0.13 ([#65](https://github.com/shssoichiro/oxipng/pull/65))
-- Bump `image` to 0.13 ([#65](https://github.com/oxipng/oxipng/pull/65))
+ - Bump `rayon` to 0.7
-- Bump `rayon` to 0.7
+ - Bump `itertools` to 0.6
-- Bump `itertools` to 0.6
 
 ### Version 0.15.1
-
+ - Ignore color reductions that would increase file size ([#61](https://github.com/shssoichiro/oxipng/issues/61))
-- Ignore color reductions that would increase file size ([#61](https://github.com/oxipng/oxipng/issues/61))
 
 ### Version 0.15.0
-
+ - [SEMVER_MINOR] Check images for correctness before writing result ([#60](https://github.com/shssoichiro/oxipng/issues/60))
-- [SEMVER_MINOR] Check images for correctness before writing result ([#60](https://github.com/oxipng/oxipng/issues/60))
+ - Fix invalid output when reducing image to a different color type but file size does not improve ([#60](https://github.com/shssoichiro/oxipng/issues/60))
-- Fix invalid output when reducing image to a different color type but file size does not improve ([#60](https://github.com/oxipng/oxipng/issues/60))
+ - Don't write new file if moving from interlaced to non-interlaced if new file would be larger
-- Don't write new file if moving from interlaced to non-interlaced if new file would be larger
 
 ### Version 0.14.4
-
+ - Fix bug when reducing RGBA to Indexed if image has 256 colors plus a background color
-- Fix bug when reducing RGBA to Indexed if image has 256 colors plus a background color
 
 ### Version 0.14.3
-
+ - Fix multiple bugs when reducing transparency palettes
-- Fix multiple bugs when reducing transparency palettes
 
 ### Version 0.14.2
-
+ - Fix a bug when reducing palette in images with bit depth less than 8
-- Fix a bug when reducing palette in images with bit depth less than 8
+ - Fix a bug when reducing palette in images with transparency
-- Fix a bug when reducing palette in images with transparency
 
 ### Version 0.14.1
-
+ - Remove zlib dependency and switch entirely to miniz, since zlib 1.2.11 was not working with oxipng. This costs some performance, but is better than having a broken application.
-- Remove zlib dependency and switch entirely to miniz, since zlib 1.2.11 was not working with oxipng. This costs some performance, but is better than having a broken application.
 
 ### Version 0.14.0
-
+ - Performance optimizations
-- Performance optimizations
+ - [SEMVER_MAJOR] Bump minimum rustc version to 1.13.0
-- [SEMVER_MAJOR] Bump minimum rustc version to 1.13.0
+ - Add categories on crates.io
-- Add categories on crates.io
 
 ### Version 0.13.1
-
+ - Bump regex dependency to 0.2
-- Bump regex dependency to 0.2
+ - Bump byteorder dependency to 1.0
-- Bump byteorder dependency to 1.0
+ - Bump rayon dependency to 0.6
-- Bump rayon dependency to 0.6
 
 ### Version 0.13.0
-
+ - Fix bug in certain PNG headers when reducing color type ([#52](https://github.com/shssoichiro/oxipng/issues/52))
-- Fix bug in certain PNG headers when reducing color type ([#52](https://github.com/oxipng/oxipng/issues/52))
+ - [SEMVER_MAJOR] Reduction functions now take `&mut PngData` and return a `bool` indicating whether the image was reduced
-- [SEMVER_MAJOR] Reduction functions now take `&mut PngData` and return a `bool` indicating whether the image was reduced
+ - [SMEVER_MAJOR] Bump minimum required rustc version to 1.12.0
-- [SMEVER_MAJOR] Bump minimum required rustc version to 1.12.0
 
 ### Version 0.12.0
-
+ - Performance optimizations
-- Performance optimizations
+ - Fix processing filenames that contain commas (@aliceatlas [#50](https://github.com/shssoichiro/oxipng/pull/50))
-- Fix processing filenames that contain commas (@aliceatlas [#50](https://github.com/oxipng/oxipng/pull/50))
+ - [SEMVER_MINOR] Add zopfli option (-Z), disabled by default. Gives about 10% better compression, but is currently 50-100x slower.
-- [SEMVER_MINOR] Add zopfli option (-Z), disabled by default. Gives about 10% better compression, but is currently 50-100x slower.
 
 ### Version 0.11.0
-
+ - [SEMVER_MAJOR] Bump minimum rustc version to 1.9.0, required by dependencies
-- [SEMVER_MAJOR] Bump minimum rustc version to 1.9.0, required by dependencies
+ - [SEMVER_MINOR] Allow calling optimization presets via crate using `Options::from_preset`
-- [SEMVER_MINOR] Allow calling optimization presets via crate using `Options::from_preset`
+ - [SEMVER_MAJOR] Return proper `PngError` type which implements `std::error::Error` from `Result`s
-- [SEMVER_MAJOR] Return proper `PngError` type which implements `std::error::Error` from `Result`s
+ - [SEMVER_MAJOR] Rename module `deflate::deflate` to `deflate`
-- [SEMVER_MAJOR] Rename module `deflate::deflate` to `deflate`
+ - Performance optimizations
-- Performance optimizations
 
 ### Version 0.10.0
-
+ - [SEMVER_MINOR] Make clap and regex dependencies optional
-- [SEMVER_MINOR] Make clap and regex dependencies optional
+   - Enabled by default, needed for executable build; can be disabled for use in crates
-  - Enabled by default, needed for executable build; can be disabled for use in crates
+ - Remove reduction from palette to grayscale, which was not working and provided minimal benefit
-- Remove reduction from palette to grayscale, which was not working and provided minimal benefit
 
 ### Version 0.9.0
-
+ - [SEMVER_MAJOR] Significant refactoring of modules
-- [SEMVER_MAJOR] Significant refactoring of modules
+ - Use `itertools` to cleanup areas of code
-- Use `itertools` to cleanup areas of code
+ - Use multiple threads for filtering trials
-- Use multiple threads for filtering trials
 
 ### Version 0.8.2
-
+ - Fix issue where images smaller than 4px width would crash on interlacing ([#42](https://github.com/shssoichiro/oxipng/issues/42))
-- Fix issue where images smaller than 4px width would crash on interlacing ([#42](https://github.com/oxipng/oxipng/issues/42))
 
 ### Version 0.8.1
-
+ - Minor optimizations
-- Minor optimizations
+ - Fix issue where interlaced images with certain widths would fail to optimize
-- Fix issue where interlaced images with certain widths would fail to optimize
 
 ### Version 0.8.0
-
+ - [SEMVER_MINOR] Add support for optimizing PNGs already loaded into memory via library function
-- [SEMVER_MINOR] Add support for optimizing PNGs already loaded into memory via library function
 
 ### Version 0.7.0
-
+ - Minor compression improvement on interlaced images
-- Minor compression improvement on interlaced images
+ - Performance optimizations
-- Performance optimizations
+ - [SEMVER_MINOR] Move default Options into a Default impl
-- [SEMVER_MINOR] Move default Options into a Default impl
+ - [SEMVER_MINOR] Add option for setting number of threads ([#39](https://github.com/shssoichiro/oxipng/issues/39))
-- [SEMVER_MINOR] Add option for setting number of threads ([#39](https://github.com/oxipng/oxipng/issues/39))
 
 ### Version 0.6.0
-
+ - Fix issue where output directory would not be created if it did not exist
-- Fix issue where output directory would not be created if it did not exist
+ - Use miniz for compression strategies where it outperforms zlib
-- Use miniz for compression strategies where it outperforms zlib
+ - [SEMVER_MINOR] Partially implement -p / --preserve, as far as stable Rust will allow for now
-- [SEMVER_MINOR] Partially implement -p / --preserve, as far as stable Rust will allow for now
+ - [SEMVER_MINOR] Implement --fix to ignore CRC errors and recalculate correct CRC in output
-- [SEMVER_MINOR] Implement --fix to ignore CRC errors and recalculate correct CRC in output
 
 ### Version 0.5.0
-
+ - [SEMVER_MINOR] Palette entries can now reduced, on by default ([#11](https://github.com/shssoichiro/oxipng/issues/11))
-- [SEMVER_MINOR] Palette entries can now reduced, on by default ([#11](https://github.com/oxipng/oxipng/issues/11))
+ - Don't report that we are in pretend mode if verbosity is set to none
-- Don't report that we are in pretend mode if verbosity is set to none
+ - Add cargo bench suite ([#7](https://github.com/shssoichiro/oxipng/issues/7))
-- Add cargo bench suite ([#7](https://github.com/oxipng/oxipng/issues/7))
 
 ### Version 0.4.0
-
+ - Performance optimizations
-- Performance optimizations
+ - [SEMVER_MAJOR] `-s` automatically infers `--strip safe` ([#31](https://github.com/shssoichiro/oxipng/issues/31))
-- [SEMVER_MAJOR] `-s` automatically infers `--strip safe` ([#31](https://github.com/oxipng/oxipng/issues/31))
+ - Update byteorder and clap crates
-- Update byteorder and clap crates
+ - Fix issue where interlaced images incorrectly applied filters on the first line of a pass
-- Fix issue where interlaced images incorrectly applied filters on the first line of a pass
 
 ### Version 0.3.0
-
+ - Properly decode interlaced images
-- Properly decode interlaced images
+ - [SEMVER_MINOR] Allow converting between progressive and interlaced images ([#3](https://github.com/shssoichiro/oxipng/issues/3))
-- [SEMVER_MINOR] Allow converting between progressive and interlaced images ([#3](https://github.com/oxipng/oxipng/issues/3))
+ - Fix a bug that would cause oxipng to crash on very small images
-- Fix a bug that would cause oxipng to crash on very small images
 
 ### Version 0.2.2
-
+ - Limit number of threads to 1.5x number of cores
-- Limit number of threads to 1.5x number of cores
+ - Significantly improve memory usage, especially with high optimization levels. ([#32](https://github.com/shssoichiro/oxipng/issues/32))
-- Significantly improve memory usage, especially with high optimization levels. ([#32](https://github.com/oxipng/oxipng/issues/32))
+ - Refactor output code ([#19](https://github.com/shssoichiro/oxipng/issues/19))
-- Refactor output code ([#19](https://github.com/oxipng/oxipng/issues/19))
 
 ### Version 0.2.1
-
+ - Add rustdoc for public methods and structs
-- Add rustdoc for public methods and structs
+ - Improve filter mode 5 heuristic ([#16](https://github.com/shssoichiro/oxipng/issues/16))
-- Improve filter mode 5 heuristic ([#16](https://github.com/oxipng/oxipng/issues/16))
+ - Add tests for edge-case images with subtitles ([#29](https://github.com/shssoichiro/oxipng/issues/29))
-- Add tests for edge-case images with subtitles ([#29](https://github.com/oxipng/oxipng/issues/29))
 
 ### Version 0.2.0
-
+ - Fix program version that is displayed when running `oxipng -V`
-- Fix program version that is displayed when running `oxipng -V`
+ - Ensure `--quiet` mode is actually quiet (@SethDusek [#20](https://github.com/shssoichiro/oxipng/pull/20))
-- Ensure `--quiet` mode is actually quiet (@SethDusek [#20](https://github.com/oxipng/oxipng/pull/20))
+ - Write status/debug information to stderr instead of stdout
-- Write status/debug information to stderr instead of stdout
+ - Use heuristics to determine best combination for `-o1` ([#21](https://github.com/shssoichiro/oxipng/issues/21))
-- Use heuristics to determine best combination for `-o1` ([#21](https://github.com/oxipng/oxipng/issues/21))
+ - [SEMVER_MAJOR] Allow 'safe', 'all', or comma-separated list as options for `--strip`
-- [SEMVER_MAJOR] Allow 'safe', 'all', or comma-separated list as options for `--strip`
+ - [SEMVER_MINOR] Add `-s` alias for `--strip`
-- [SEMVER_MINOR] Add `-s` alias for `--strip`
 
 ### Version 0.1.1
-
+ - Fix `oxipng *` writing all input files to one output file ([#15](https://github.com/shssoichiro/oxipng/issues/15))
-- Fix `oxipng *` writing all input files to one output file ([#15](https://github.com/oxipng/oxipng/issues/15))
 
 ### Version 0.1.0
-
+ - Initial beta release
-- Initial beta release
+ - Reduce color type and bit depth
-- Reduce color type and bit depth
+ - Recompress with zlib
-- Recompress with zlib
+ - Multithreading
-- Multithreading
+ - Strip headers option
-- Strip headers option
+ - Backup file before writing option
-- Backup file before writing option
+ - Write to stdout option
-- Write to stdout option

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Cargo.toml

@@ -1,30 +1,23 @@
 [package]
 authors = ["Joshua Holmer <jholmer.in@gmail.com>"]
-categories = ["command-line-utilities", "compression"]
+categories = [
-description = "A lossless PNG compression optimizer"
+    "command-line-utilities",
-keywords = ["png", "image-compression", "optimization", "multi-threading", "lossless"]
+    "compression",
-documentation = "https://docs.rs/oxipng"
-edition = "2024"
-exclude = [
-  ".editorconfig",
-  ".gitattributes",
-  ".github/*",
-  ".gitignore",
-  ".pre-commit-hooks.yaml",
-  "Dockerfile",
-  "scripts/*",
-  "tests/*",
-  "xtask/*",
 ]
-homepage = "https://github.com/oxipng/oxipng"
+description = "A lossless PNG compression optimizer"
+documentation = "https://docs.rs/oxipng"
+exclude = [
+    "tests/*",
+    "bench/*",
+]
+homepage = "https://github.com/shssoichiro/oxipng"
 license = "MIT"
 name = "oxipng"
-repository = "https://github.com/oxipng/oxipng"
+repository = "https://github.com/shssoichiro/oxipng"
-version = "10.1.1"
+version = "2.1.5"
-rust-version = "1.85.1"
 
 [badges]
-travis-ci = { repository = "oxipng/oxipng", branch = "master" }
+travis-ci = { repository = "shssoichiro/oxipng", branch = "master" }
 maintenance = { status = "actively-developed" }
 
 [[bin]]
@@ -33,89 +26,53 @@ name = "oxipng"
 path = "src/main.rs"
 required-features = ["binary"]
 
-[[bench]]
-name = "zopfli"
-required-features = ["zopfli"]
-
 [dependencies]
-bitvec = "1.0.1"
+bit-vec = "^0.5.0"
-clap = { version = "4.6.0", optional = true, features = ["wrap_help"] }
+byteorder = "^1.0.0"
-env_logger = { version = "0.11.10", optional = true, default-features = false, features = ["auto-color"] }
+crc = "^1.2.0"
-image = { version = "0.25.9", optional = true, default-features = false, features = ["png"] }
+itertools = "^0.7.7"
-indexmap = "2.14.0"
+num_cpus = "^1.0.0"
-libdeflater = "1.25.2"
+zopfli = "^0.3.4"
-log = "0.4.30"
+miniz_oxide = "0.1.2"
-parse-size = { version = "1.1.0", optional = true }
-rayon = { version = "1.11.0", optional = true }
-rgb = "0.8.53"
-rustc-hash = "2.1.2"
-zopfli = { version = "0.8.3", optional = true, default-features = false, features = ["std", "zlib"] }
 
-[target.'cfg(windows)'.dependencies]
+[dependencies.rayon]
-glob = { version = "0.3.3", optional = true }
+optional = true
+version = "^1.0.0"
 
-[dev-dependencies]
+[dependencies.clap]
-serde_json = "1.0.150"
+optional = true
+version = "^2.10.0"
+
+[dependencies.wild]
+optional = true
+version = "2.0.0"
+
+[target.'cfg(any(target_arch = "x86_64", target_arch = "aarch64"))'.dependencies]
+cloudflare-zlib-sys = "^0.1.2"
+
+[dependencies.image]
+default-features = false
+features = ["png_codec"]
+version = "^0.20.0"
 
 [features]
-binary = ["dep:clap", "dep:glob", "dep:env_logger", "dep:parse-size"]
+binary = [
-default = ["binary", "parallel", "zopfli"]
+    "clap",
-parallel = ["dep:rayon", "indexmap/rayon"]
+    "wild",
-freestanding = ["libdeflater/freestanding"]
+]
-sanity-checks = ["dep:image"]
+default = ["binary", "parallel"]
-zopfli = ["dep:zopfli"]
+parallel = ["rayon"]
-system-libdeflate = ["libdeflater/dynamic"]
+dev = [
+    "nightly-binary",
+]
+nightly = []
+nightly-binary = [
+    "binary",
+    "nightly",
+]
 
 [lib]
 name = "oxipng"
 path = "src/lib.rs"
-
 [profile.dev]
 opt-level = 2
-
-[profile.release]
-lto = "fat"
-strip = "symbols"
-panic = "abort"
-
-[package.metadata.deb]
-assets = [
-    ["target/release/oxipng", "usr/bin/", "755"],
-    ["target/xtask/mangen/manpages/oxipng.1", "usr/share/man/man1/", "644"],
-    ["README.md", "usr/share/doc/oxipng/", "644"],
-    ["CHANGELOG.md", "usr/share/doc/oxipng/", "644"],
-]
-
-[lints.rust]
-missing_copy_implementations = "deny"
-missing_debug_implementations = "deny"
-trivial_casts = "warn"
-trivial_numeric_casts = "warn"
-unused_import_braces = "warn"
-
-[lints.clippy]
-cloned_instead_of_copied = "warn"
-expl_impl_clone_on_copy = "warn"
-float_cmp_const = "warn"
-if_not_else = "warn"
-ignored_unit_patterns = "warn"
-linkedlist = "warn"
-manual_let_else = "warn"
-map_flatten = "warn"
-map_unwrap_or = "warn"
-match_same_arms = "warn"
-mem_forget = "warn"
-missing_const_for_fn = "warn"
-mut_mut = "warn"
-mutex_integer = "warn"
-needless_continue = "warn"
-option_if_let_else = "warn"
-path_buf_push_overwrite = "warn"
-range_plus_one = "warn"
-redundant_clone = "warn"
-redundant_closure_for_method_calls = "warn"
-semicolon_if_nothing_returned = "warn"
-unnecessary_semicolon = "warn"
-unseparated_literal_suffix = "warn"
-use_self = "warn"
-useless_let_if_seq = "warn"

Dockerfile

@@ -1,46 +0,0 @@
-# syntax=docker/dockerfile:1
-# check=error=true
-FROM --platform=$BUILDPLATFORM tonistiigi/xx AS xx
-
-FROM --platform=$BUILDPLATFORM rust:1.85.1-alpine AS base
-
-RUN apk update && \
-    apk add \
-        gcc \
-        g++ \
-        clang
-
-COPY --from=xx / /
-
-ARG TARGETPLATFORM
-RUN xx-info env
-
-RUN xx-apk add \
-    gcc \
-    musl-dev \
-    libdeflate
-
-WORKDIR /src
-
-COPY . .
-
-RUN --mount=type=cache,target=/root/.cargo/git/db \
-    --mount=type=cache,target=/root/.cargo/registry/cache \
-    --mount=type=cache,target=/root/.cargo/registry/index \
-    xx-cargo build --release && \
-    xx-verify /src/target/$(xx-cargo --print-target-triple)/release/oxipng && \
-    cp /src/target/$(xx-cargo --print-target-triple)/release/oxipng /src/target/oxipng
-
-FROM scratch AS tool
-
-LABEL org.opencontainers.image.title="Oxipng"
-LABEL org.opencontainers.image.description="Multithreaded PNG optimizer written in Rust"
-LABEL org.opencontainers.image.authors="Joshua Holmer <jholmer.in@gmail.com>"
-LABEL org.opencontainers.image.licenses="MIT"
-LABEL org.opencontainers.image.source="https://github.com/oxipng/oxipng"
-
-COPY --from=base /src/target/oxipng /usr/local/bin/oxipng
-
-WORKDIR /work
-ENTRYPOINT [ "oxipng" ]
-CMD [ "--help" ]

MANUAL.txt

@@ -1,227 +0,0 @@
-oxipng 10.1.0
-Losslessly improve compression of PNG files
-
-Usage: oxipng [OPTIONS] <files>...
-
-Arguments:
-  <files>...
-          File(s) to compress (use '-' for stdin)
-
-Options:
-  -o, --opt <level>
-          Set the optimization level preset. The default level 2 is quite fast and provides good
-          compression. Lower levels are faster, higher levels provide better compression, though
-          with increasingly diminishing returns.
-          
-              0   => --zc 5  --fast              (filter chosen heuristically)
-              1   => --zc 10 --fast              (filter chosen heuristically)
-              2   => --zc 11 -f 0,1,6,7 --fast
-              3   => --zc 11 -f 0,7,8,9         --brute-level 1 --brute-lines 3
-              4   => --zc 12 -f 0,7,8,9         --brute-level 1 --brute-lines 4
-              5   => --zc 12 -f 0,1,2,5,6,7,8,9 --brute-level 4 --brute-lines 4
-              6   => --zc 12 -f 0-9             --brute-level 5 --brute-lines 8
-              max => (stable alias for the maximum level)
-          
-          Manually specifying a compression option (zc, f, etc.) will override the optimization
-          preset, regardless of the order you write the arguments.
-          
-          [default: 2]
-
-  -r, --recursive
-          When directories are given as input, traverse the directory trees and optimize all PNG
-          files found (files with “.png” or “.apng” extension).
-
-      --dir <directory>
-          Write output file(s) to <directory>. If the directory does not exist, it will be created.
-          Note that this will not preserve the directory structure of the input files when used with
-          '--recursive'.
-
-      --out <file>
-          Write output file to <file>
-
-      --stdout
-          Write output to stdout
-
-  -p, --preserve
-          Preserve file permissions and timestamps if possible
-
-  -d, --dry-run
-          Do not write any files, only show compression results
-
-  -s
-          Strip safely-removable chunks, same as '--strip safe'
-
-      --strip <mode>
-          Strip metadata chunks, where <mode> is one of:
-          
-              safe    =>  Strip all non-critical chunks, except for the following:
-                              cICP, iCCP, sRGB, pHYs, acTL, fcTL, fdAT
-              all     =>  Strip all non-critical chunks
-              <list>  =>  Strip chunks in the comma-separated list, e.g. 'bKGD,cHRM'
-          
-          CAUTION: 'all' will convert APNGs to standard PNGs.
-          
-          Please note that regardless of any options set, some chunks will necessarily be stripped
-          when invalidated by the optimization:
-              bKGD, sBIT, hIST: Stripped if the color type or bit depth changes.
-              iDOT: Always stripped.
-              caBX: Stripped if it contains C2PA metadata. If explicitly retained by `--keep`,
-              optimization will be aborted.
-          
-          The default when --strip is not passed is to keep all chunks that remain valid.
-
-      --keep <list>
-          Strip all metadata chunks except those in the comma-separated list. The special value
-          'display' includes chunks that affect the image appearance, equivalent to '--strip safe'.
-          
-          E.g. '--keep eXIf,display' will strip chunks, keeping only eXIf and those that affect the
-          image appearance.
-
-  -a, --alpha
-          Perform additional optimization on images with an alpha channel, by altering the color
-          values of fully transparent pixels. This is generally recommended for better compression,
-          but take care as while this is “visually lossless”, it is technically a lossy
-          transformation and may be unsuitable for some applications.
-
-  -i, --interlace <mode>
-          Set the PNG interlacing mode, where <mode> is one of:
-          
-              off   =>  Remove interlacing from all images that are processed
-              on    =>  Apply Adam7 interlacing on all images that are processed
-              keep  =>  Keep the existing interlacing mode of each image
-          
-          Note that interlacing can add 25-50% to the size of an optimized image. Only use it if you
-          believe the benefits outweigh the costs for your use case.
-          
-          [default: off]
-
-      --scale16
-          Forcibly reduce images with 16 bits per channel to 8 bits per channel. This is a lossy
-          operation but can provide significant savings when you have no need for higher depth.
-          Reduction is performed by scaling the values such that, e.g. 0x00FF is reduced to 0x01
-          rather than 0x00.
-          
-          Without this flag, 16-bit images will only be reduced in depth if it can be done
-          losslessly.
-
-  -v, --verbose...
-          Show per-file info (use multiple times for more detail)
-
-  -q, --quiet
-          Suppress all output messages
-
-  -j, --json
-          Print results as JSON
-
-  -f, --filters <list>
-          Perform compression trials with each of the given filter types. You can specify a
-          comma-separated list, or a range of values. E.g. '-f 0-3' is the same as '-f 0,1,2,3'.
-          
-          PNG delta filters (apply the same filter to every line)
-              0  =>  None      (recommended to always include this filter)
-              1  =>  Sub
-              2  =>  Up
-              3  =>  Average
-              4  =>  Paeth
-          
-          Heuristic strategies (try to find the best delta filter for each line)
-              5  =>  MinSum    Minimum sum of absolute differences
-              6  =>  Entropy   Smallest Shannon entropy
-              7  =>  Bigrams   Lowest count of distinct bigrams
-              8  =>  BigEnt    Smallest Shannon entropy of bigrams
-              9  =>  Brute     Smallest compressed size (slow)
-          
-          The default value depends on the optimization level preset.
-
-      --fast
-          Perform a fast compression evaluation of each enabled filter, followed by a single main
-          compression trial of the best result. Recommended if you have more filters enabled than
-          CPU cores.
-
-      --zc <level>
-          Deflate compression level (0-12) for main compression trials. The levels here are defined
-          by the libdeflate compression library.
-          
-          The default value depends on the optimization level preset.
-
-      --nb
-          Do not change bit depth
-
-      --nc
-          Do not change color type
-
-      --np
-          Do not change color palette
-
-      --ng
-          Do not change to or from grayscale
-
-      --nx
-          Do not perform any transformations and do not deinterlace by default.
-
-      --nz
-          Do not recompress IDAT unless required due to transformations. Recompression of other
-          compressed chunks (such as iCCP) will also be disabled. Note that the combination of
-          '--nx' and '--nz' will fully disable all optimization.
-
-      --fix
-          Do not perform checksum validation of PNG chunks. This may allow some files with errors to
-          be processed successfully. The output will always have correct checksums.
-
-      --force
-          Write the output even if it is larger than the input
-
-  -z, --zopfli
-          Use the much slower but stronger Zopfli compressor for main compression trials.
-          Recommended use is with '-o max' and '--fast'.
-
-      --zi <iterations>
-          Set the number of iterations to use for Zopfli compression. Using fewer iterations may
-          speed up compression for large files. This option requires '--zopfli' to be set.
-          
-          [default: 15]
-
-      --ziwi <iterations>
-          Stop Zopfli compression after this number of iterations without improvement. Use this in
-          conjunction with a high value for '--zi' to achieve better compression in reasonable time.
-
-      --brute-level <level>
-          Set the libdeflate compression level to use with the Brute filter strategy. Sane values
-          are 1-5. Higher values are not necessarily better.
-
-      --brute-lines <lines>
-          Set the number of lines to compress at once with the Brute filter strategy. Sane values
-          are 2-16. Higher values are not necessarily better.
-
-      --timeout <secs>
-          Maximum amount of time, in seconds, to spend on optimizations. Oxipng will check the
-          timeout before each transformation or compression trial, and will stop trying to optimize
-          the file if the timeout is exceeded. Note that this does not cut short any operations that
-          are already in progress, so it is currently of limited effectiveness for large files with
-          high compression levels.
-
-      --max-raw-size <bytes>
-          Maximum size to allow for the input image. If the raw, decompressed image data (or the
-          file size) of the image exceeds this size, it will be skipped. This is useful for limiting
-          memory usage or avoiding long processing times on large images. The value may be specified
-          with a unit suffix such as k, KB, m, MB, etc.
-          
-          The decompressed size of an image is roughly equal to width * height * bit-depth / 8. E.g.
-          a 1920x1080 image with 24-bit color depth would be roughly 6MB.
-
-  -t, --threads <num>
-          Set the maximum number of threads to use. Oxipng uses multithreading to evaluate multiple
-          optimizations on the same file in parallel as well as process multiple files in parallel.
-          You can set this to a lower value if you need to limit memory or CPU usage.
-          
-          [default: num logical CPUs]
-
-      --sequential
-          Process multiple files sequentially rather than in parallel. Use this if you need
-          determinism in the processing order. Note this is not necessary if using '--threads 1'.
-
-  -h, --help
-          Print help (see a summary with '-h')
-
-  -V, --version
-          Print version

README.md

@@ -1,150 +1,84 @@
 # Oxipng
 
-[![Build Status](https://github.com/oxipng/oxipng/workflows/oxipng/badge.svg)](https://github.com/oxipng/oxipng/actions?query=branch%3Amaster)
+[![Build Status](https://travis-ci.org/shssoichiro/oxipng.svg?branch=master)](https://travis-ci.org/shssoichiro/oxipng)
 [![Version](https://img.shields.io/crates/v/oxipng.svg)](https://crates.io/crates/oxipng)
-[![License](https://img.shields.io/crates/l/oxipng.svg)](https://github.com/oxipng/oxipng/blob/master/LICENSE)
+[![License](https://img.shields.io/crates/l/oxipng.svg)](https://github.com/shssoichiro/oxipng/blob/master/LICENSE)
-[![Docs](https://docs.rs/oxipng/badge.svg)](https://docs.rs/oxipng)
 
 ## Overview
 
-Oxipng is a multithreaded lossless PNG/APNG compression optimizer. It can be used via a command-line
+Oxipng is a multithreaded lossless PNG compression optimizer. It can be used via a command-line
-interface or as a library in other Rust programs. It is fast and highly effective.
+interface or as a library in other Rust programs.
 
 ## Installing
 
-Oxipng for Windows can be downloaded via the
+Oxipng can be downloaded from the [Releases](https://github.com/shssoichiro/oxipng/releases) link on the GitHub page.
-[Releases](https://github.com/oxipng/oxipng/releases) section on its GitHub page. Recently,
-however, Oxipng has also been made available through package managers. Check the list below for
-up-to-date options.
-
-For MacOS or Linux, it is recommended to install from your distro's package repository, provided
-Oxipng is available there in a not too outdated version for your use case.
-
-Oxipng is known to be packaged for the environments listed below.
-
-[![Packaging status](https://repology.org/badge/vertical-allrepos/oxipng.svg?exclude_unsupported=1&columns=3&exclude_sources=modules,site)](https://repology.org/project/oxipng/versions)
-
-Alternatively, Oxipng can be installed from Cargo, via the following command:
 
+Oxipng can also be installed from Cargo, via the following command:
 ```
 cargo install oxipng
 ```
 
-Oxipng can also be built from source using the latest stable or nightly Rust.
+Alternatively, oxipng can be built from source using the latest stable or nightly Rust:
-This is primarily useful for developing on Oxipng.
-
 ```
-git clone https://github.com/oxipng/oxipng.git
+git clone https://github.com/shssoichiro/oxipng.git
 cd oxipng
 cargo build --release
 cp target/release/oxipng /usr/local/bin
 ```
 
-The current minimum supported Rust version is **1.85.1**.
+The current minimum supported Rust version is **1.27.0**. Oxipng may compile on earlier versions of Rust,
+but there is no guarantee.
 
 Oxipng follows Semantic Versioning.
 
 ## Usage
 
-Oxipng is a command-line utility. An example usage, suitable for web, may be the following:
+Oxipng is a command-line utility. Basic usage looks similar to the following:
 
 ```
-oxipng -o 4 --strip safe --alpha *.png
+oxipng -o 4 -i 1 --strip safe *.png
 ```
 
 The most commonly used options are as follows:
+* Optimization: `-o 1` through `-o 6`, lower is faster, higher is better compression.
+The default (`-o 2`) is sufficiently fast on a modern CPU and provides 30-50% compression
+gains over an unoptimized PNG. `-o 4` is 6 times slower than `-o 2` but can provide 5-10%
+extra compression over `-o 2`. Using any setting higher than `-o 4` is unlikely
+to give any extra compression gains and is not recommended.
+* Interlacing: `-i 1` will enable [Adam7](https://en.wikipedia.org/wiki/Adam7_algorithm)
+PNG interlacing on any images that are processed. `-i 0` will remove interlacing from all
+processed images. Not specifying either will keep the same interlacing state as the
+input image. Note: Interlacing can add 25-50% to the size of an optimized image. Only use
+it if you believe the benefits outweight the costs for your use case.
+* Strip: Used to remove metadata info from processed images. Used via `--strip [safe,all]`.
+Can save a few kilobytes if you don't need the metadata. "Safe" removes only metadata that
+will never affect rendering of the image. "All" removes all metadata that is not critical
+to the image. You can also pass a comma-separated list of specific metadata chunks to remove.
+`-s` can be used as a shorthand for `--strip safe`.
 
-- Optimization: `-o 0` through `-o 6` (or `-o max`), lower is faster, higher is better compression.
+More advanced options can be found by running `oxipng -h`.
-  The default (`-o 2`) is quite fast and provides good compression. Higher levels can be notably
-  better* but generally have increasingly diminishing returns.
-- Strip: Used to remove metadata info from processed images. Used via `--strip [safe,all]`.
-  Can save a few kilobytes if you don't need the metadata. "Safe" removes only metadata that
-  will never affect rendering of the image. "All" removes all metadata that is not critical
-  to the image. You can also pass a comma-separated list of specific metadata chunks to remove.
-  `-s` can be used as a shorthand for `--strip safe`.
-- Alpha: `--alpha` can improve compression of images with transparency, by altering the color
-  values of fully transparent pixels. This is generally recommended, but take care as this is
-  technically a lossy transformation and may be unsuitable for some specific applications.
-
-More advanced options can be found by running `oxipng --help`, or viewed [here](MANUAL.txt).
-
-Some options have both short (`-a`) and long (`--alpha`) forms. Which form you use is just a
-matter of preference. Multiple short options can be combined together, e.g.:
-`-savvo6` is equivalent to to `--strip safe --alpha --verbose --verbose --opt 6`.
-All options are case-sensitive.
-
-\* Note that oxipng is not a brute-force optimizer. This means that while higher optimization levels
-are almost always better or equal to lower levels, this is not guaranteed and it is possible in
-rare circumstances that a lower level may give a marginally smaller output. Similarly, using Zopfli
-compression (`-z`) is not guaranteed to always be better than default compression.
-
-## APNG support
-
-Oxipng currently only supports limited optimization of animated PNGs (APNGs). It can perform
-alpha-optimization, refiltering and recompression of all frames, but all transformations will be
-disabled. For best results, it is recommended to use another tool such as
-[apngopt](https://sourceforge.net/projects/apng/files/APNG_Optimizer/) before running Oxipng.
-
-## Git integration via [pre-commit]
-
-Create a `.pre-commit-config.yaml` file like this, or add the lines after the `repos` map
-preamble to an already existing one:
-
-```yaml
-repos:
-  - repo: https://github.com/oxipng/oxipng
-    rev: v10.0.0
-    hooks:
-      - id: oxipng
-        args: ["-o", "4", "--strip", "safe", "--alpha"]
-```
-[pre-commit]: https://pre-commit.com/
-
-## Docker
-
-A Docker image is availlable at [`ghcr.io/oxipng/oxipng`](https://github.com/oxipng/oxipng/pkgs/container/oxipng) for `linux/amd64` and `linux/arm64`.
-
-You can use it the following way:
-
-```bash
-docker run --rm -v $(pwd):/work ghcr.io/oxipng/oxipng -o 4 /work/file.png
-```
-
-Some older images are also available at [`ghcr.io/shssoichiro/oxipng`](https://github.com/users/shssoichiro/packages/container/package/oxipng).
 
 ## Library Usage
 
-Although originally intended to be used as an executable, Oxipng can also be used as a library in
+Although originally intended to be used as an executable, oxipng can also be used as a library in
-other Rust projects. To do so, simply add Oxipng as a dependency in your Cargo.toml. You should then
+other Rust projects. To do so, simply add oxipng as a dependency in your Cargo.toml,
-have access to all of the library functions [documented here](https://docs.rs/oxipng). The simplest
+then `extern crate oxipng` in your project. You should then have access to all of the library
-method of usage involves creating an [Options
+functions [documented here](https://docs.rs/oxipng). The simplest
-struct](https://docs.rs/oxipng/latest/oxipng/struct.Options.html) and passing it, along with an
+method of usage involves creating an
-input filename, into the [optimize function](https://docs.rs/oxipng/latest/oxipng/fn.optimize.html).
+[Options struct](https://docs.rs/oxipng/0.13.0/oxipng/struct.Options.html) and
-
+passing it, along with an input filename, into the
-It is recommended to disable the "binary" feature when including Oxipng as a library. Currently, there is
+[optimize function](https://docs.rs/oxipng/0.13.0/oxipng/fn.optimize.html).
-no simple way to just disable one feature in Cargo, it has to be done by disabling default features
-and specifying the desired ones, for example:
-`oxipng = { version = "10.0", features = ["parallel", "zopfli", "filetime"], default-features = false }`
-
-## Software using Oxipng
-
-- [ImageOptim](https://imageoptim.com): Mac app and web service for optimizing images
-- [Squoosh](https://squoosh.app): Web app for optimizing images
-- [FileOptimizer](https://nikkhokkho.sourceforge.io/?page=FileOptimizer): Windows app for optimizing files
-- [Curtail](https://github.com/Huluti/Curtail): Linux app for optimizing images
-- [pyoxipng](https://pypi.org/project/pyoxipng/): Python wrapper for Oxipng
-- [jSquash](https://github.com/jamsinclair/jSquash): Collection of WebAssembly image codecs
-- [Trunk](https://trunk.io): Developer experience toolkit for managing code
 
 ## History
 
-Oxipng began in 2015 as a rewrite of the OptiPNG project. The core goal was to implement
+Oxipng began as a complete rewrite of the OptiPNG project,
-multithreading, which would have been very difficult to do within the existing C codebase of OptiPNG.
+which was assumed to be dead as no commit had been made to it since March 2014.
-This also served as an opportunity to choose a more modern, safer language (Rust).
+(OptiPNG has since released a new version, after Oxipng was first released.)
+The name has been changed to avoid confusion and potential legal issues.
 
-However, Oxipng has evolved considerably since then. While some of the options remain similar to
+The core goal of rewriting OptiPNG was to implement multithreading,
-OptiPNG, the architecture and capabilities are now quite different. It is not a drop-in
+which would be very difficult to do within the existing C codebase of OptiPNG.
-replacement - if you are migrating from OptiPNG, please check the [help](MANUAL.txt) before use.
+This also served as an opportunity to choose a more modern, safer language (Rust).
 
 ## Contributing
 
@@ -154,11 +88,45 @@ to submit a fix with the bug report, it is preferred that you do so via pull req
 however you do not need to be a Rust developer to contribute.
 Other contributions (such as improving documentation or translations) are also welcome via GitHub.
 
-## Benchmarks
-
-An independent benchmark is linked here with permission by the author:\
-[oxipng and friends: A comparison of PNG optimization tools](https://op111.net/posts/2025/09/png-compression-oxipng-optipng-fileoptimizer-cwebp/)
-
 ## License
 
 Oxipng is open-source software, distributed under the MIT license.
+
+## Benchmarks
+
+Tested oxipng 2.1.4 (compiled on rustc 1.29.1 (b801ae664 2018-09-20)) against OptiPNG version 0.7.7 on Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz with 8 logical cores
+
+
+
+Benchmark #1: ./target/release/oxipng -P ./tests/files/rgb_16_should_be_grayscale_8.png
+
+  Time (mean ± σ):      76.1 ms ±   2.2 ms    [User: 165.1 ms, System: 26.9 ms]
+ 
+  Range (min … max):    71.1 ms …  80.4 ms
+ 
+Benchmark #2: optipng -simulate ./tests/files/rgb_16_should_be_grayscale_8.png
+
+  Time (mean ± σ):     274.9 ms ±   2.3 ms    [User: 272.8 ms, System: 2.0 ms]
+ 
+  Range (min … max):   271.8 ms … 278.1 ms
+ 
+Summary
+
+  './target/release/oxipng -P ./tests/files/rgb_16_should_be_grayscale_8.png' ran
+    3.61x faster than 'optipng -simulate ./tests/files/rgb_16_should_be_grayscale_8.png'
+Benchmark #1: ./target/release/oxipng -o4 -P ./tests/files/rgb_16_should_be_grayscale_8.png
+
+  Time (mean ± σ):     103.1 ms ±   3.1 ms    [User: 444.9 ms, System: 25.2 ms]
+ 
+  Range (min … max):    98.6 ms … 111.4 ms
+ 
+Benchmark #2: optipng -o 4 -simulate ./tests/files/rgb_16_should_be_grayscale_8.png
+
+  Time (mean ± σ):     931.3 ms ±   8.7 ms    [User: 929.6 ms, System: 1.1 ms]
+ 
+  Range (min … max):   920.4 ms … 943.3 ms
+ 
+Summary
+
+  './target/release/oxipng -o4 -P ./tests/files/rgb_16_should_be_grayscale_8.png' ran
+    9.03x faster than 'optipng -o 4 -simulate ./tests/files/rgb_16_should_be_grayscale_8.png'

README.template.md

@@ -0,0 +1,96 @@
+# Oxipng
+
+[![Build Status](https://travis-ci.org/shssoichiro/oxipng.svg?branch=master)](https://travis-ci.org/shssoichiro/oxipng)
+[![Version](https://img.shields.io/crates/v/oxipng.svg)](https://crates.io/crates/oxipng)
+[![License](https://img.shields.io/crates/l/oxipng.svg)](https://github.com/shssoichiro/oxipng/blob/master/LICENSE)
+
+## Overview
+
+Oxipng is a multithreaded lossless PNG compression optimizer. It can be used via a command-line
+interface or as a library in other Rust programs.
+
+## Installing
+
+Oxipng can be downloaded from the [Releases](https://github.com/shssoichiro/oxipng/releases) link on the GitHub page.
+
+Oxipng can also be installed from Cargo, via the following command:
+```
+cargo install oxipng
+```
+
+Alternatively, oxipng can be built from source using the latest stable or nightly Rust:
+```
+git clone https://github.com/shssoichiro/oxipng.git
+cd oxipng
+cargo build --release
+cp target/release/oxipng /usr/local/bin
+```
+
+The current minimum supported Rust version is **1.27.0**. Oxipng may compile on earlier versions of Rust,
+but there is no guarantee.
+
+Oxipng follows Semantic Versioning.
+
+## Usage
+
+Oxipng is a command-line utility. Basic usage looks similar to the following:
+
+```
+oxipng -o 4 -i 1 --strip safe *.png
+```
+
+The most commonly used options are as follows:
+* Optimization: `-o 1` through `-o 6`, lower is faster, higher is better compression.
+The default (`-o 2`) is sufficiently fast on a modern CPU and provides 30-50% compression
+gains over an unoptimized PNG. `-o 4` is 6 times slower than `-o 2` but can provide 5-10%
+extra compression over `-o 2`. Using any setting higher than `-o 4` is unlikely
+to give any extra compression gains and is not recommended.
+* Interlacing: `-i 1` will enable [Adam7](https://en.wikipedia.org/wiki/Adam7_algorithm)
+PNG interlacing on any images that are processed. `-i 0` will remove interlacing from all
+processed images. Not specifying either will keep the same interlacing state as the
+input image. Note: Interlacing can add 25-50% to the size of an optimized image. Only use
+it if you believe the benefits outweight the costs for your use case.
+* Strip: Used to remove metadata info from processed images. Used via `--strip [safe,all]`.
+Can save a few kilobytes if you don't need the metadata. "Safe" removes only metadata that
+will never affect rendering of the image. "All" removes all metadata that is not critical
+to the image. You can also pass a comma-separated list of specific metadata chunks to remove.
+`-s` can be used as a shorthand for `--strip safe`.
+
+More advanced options can be found by running `oxipng -h`.
+
+## Library Usage
+
+Although originally intended to be used as an executable, oxipng can also be used as a library in
+other Rust projects. To do so, simply add oxipng as a dependency in your Cargo.toml,
+then `extern crate oxipng` in your project. You should then have access to all of the library
+functions [documented here](https://docs.rs/oxipng). The simplest
+method of usage involves creating an
+[Options struct](https://docs.rs/oxipng/0.13.0/oxipng/struct.Options.html) and
+passing it, along with an input filename, into the
+[optimize function](https://docs.rs/oxipng/0.13.0/oxipng/fn.optimize.html).
+
+## History
+
+Oxipng began as a complete rewrite of the OptiPNG project,
+which was assumed to be dead as no commit had been made to it since March 2014.
+(OptiPNG has since released a new version, after Oxipng was first released.)
+The name has been changed to avoid confusion and potential legal issues.
+
+The core goal of rewriting OptiPNG was to implement multithreading,
+which would be very difficult to do within the existing C codebase of OptiPNG.
+This also served as an opportunity to choose a more modern, safer language (Rust).
+
+## Contributing
+
+Any contributions are welcome and will be accepted via pull request on GitHub. Bug reports can be
+filed via GitHub issues. Please include as many details as possible. If you have the capability
+to submit a fix with the bug report, it is preferred that you do so via pull request,
+however you do not need to be a Rust developer to contribute.
+Other contributions (such as improving documentation or translations) are also welcome via GitHub.
+
+## License
+
+Oxipng is open-source software, distributed under the MIT license.
+
+## Benchmarks
+

SECURITY.md

@@ -1,13 +0,0 @@
-# Security Policy
-
-## Supported Versions
-
-Only the latest version will be supported with security updates. We will not maintain old branches.
-For this reason, you should attempt to always use the latest released version.
-
-## Reporting a Vulnerability
-
-To privately report a vulnerability in oxipng, please visit [our advisories page](https://github.com/oxipng/oxipng/security/advisories) and use the button to report a vulnerability.
-We will review it as soon as possible.
-
-For vulnerabilities in dependencies, please open a pull request updating the dependency to a patched version.

appveyor.yml

@@ -0,0 +1,64 @@
+environment:
+  global:
+    # This will be used as part of the zipfile name
+    PROJECT_NAME: oxipng
+  matrix:
+    # Stable channel
+    - TARGET: i686-pc-windows-msvc
+      CHANNEL: stable
+    - TARGET: x86_64-pc-windows-msvc
+      CHANNEL: stable
+    - TARGET: x86_64-pc-windows-msvc
+      CHANNEL: nightly
+
+# Install Rust and Cargo
+# (Based on from https://github.com/rust-lang/libc/blob/master/appveyor.yml)
+install:
+  - curl -sSf -o rustup-init.exe https://win.rustup.rs
+  - rustup-init.exe --default-host %TARGET% --default-toolchain %CHANNEL% -y
+  - set PATH=%PATH%;C:\Users\appveyor\.cargo\bin
+  - rustc -Vv
+  - cargo -V
+
+# 'cargo test' takes care of building for us, so disable Appveyor's build stage. This prevents
+# the "directory does not contain a project or solution file" error.
+# source: https://github.com/starkat99/appveyor-rust/blob/master/appveyor.yml#L113
+build: false
+
+# Equivalent to Travis' `script` phase
+test_script:
+  - cargo build
+  - cargo test %TESTFLAGS%
+
+before_deploy:
+  # Generate artifacts for release
+  - SET RUSTFLAGS=-C target-feature=+crt-static
+  - cargo build --release
+  - mkdir staging
+  - copy target\release\oxipng.exe staging
+  - cd staging
+    # release zipfile will look like 'rust-everywhere-v1.2.3-x86_64-pc-windows-msvc'
+  - 7z a ../%PROJECT_NAME%-%APPVEYOR_REPO_TAG_NAME%-%TARGET%.zip *
+  - appveyor PushArtifact ../%PROJECT_NAME%-%APPVEYOR_REPO_TAG_NAME%-%TARGET%.zip
+
+deploy:
+  description: 'Windows release'
+  # All the zipped artifacts will be deployed
+  artifact: /.*\.zip/
+  # - Go to 'https://github.com/settings/tokens/new' and generate a Token with only the
+  # `public_repo` scope enabled
+  # - Then go to 'https://ci.appveyor.com/tools/encrypt' and enter the newly generated token.
+  # - Enter the "encrypted value" below
+  auth_token:
+    secure: JT77kw2p+U5Z9yM/77QjEWRFgvyaGOO2SquE5OBgUNpqSt4VDg/Mdicy8pkSvSEu
+  provider: GitHub
+  # deploy when a new tag is pushed and only on the stable channel
+  on:
+    # channel to use to produce the release artifacts
+    # NOTE make sure you only release *once* per target
+    CHANNEL: stable
+    appveyor_repo_tag: true
+
+branches:
+  only:
+    - master

benches/deflate.rs

@@ -3,61 +3,258 @@
 extern crate oxipng;
 extern crate test;
 
+use oxipng::internal_tests::*;
 use std::path::PathBuf;
-
-use oxipng::{internal_tests::*, *};
 use test::Bencher;
 
 #[bench]
-fn deflate_16_bits(b: &mut Bencher) {
+fn deflate_16_bits_strategy_0(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_16_should_be_rgb_16.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| deflate(png.raw.data.as_ref(), 12, None));
+    b.iter(|| {
+        let min = AtomicMin::new(None);
+        deflate(png.raw_data.as_ref(), 9, 0, 15, &min)
+    });
 }
 
 #[bench]
-fn deflate_8_bits(b: &mut Bencher) {
+fn deflate_8_bits_strategy_0(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_8_should_be_rgb_8.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| deflate(png.raw.data.as_ref(), 12, None));
+    b.iter(|| {
+        let min = AtomicMin::new(None);
+        deflate(png.raw_data.as_ref(), 9, 0, 15, &min)
+    });
 }
 
 #[bench]
-fn deflate_4_bits(b: &mut Bencher) {
+fn deflate_4_bits_strategy_0(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_4_should_be_palette_4.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| deflate(png.raw.data.as_ref(), 12, None));
+    b.iter(|| {
+        let min = AtomicMin::new(None);
+        deflate(png.raw_data.as_ref(), 9, 0, 15, &min)
+    });
 }
 
 #[bench]
-fn deflate_2_bits(b: &mut Bencher) {
+fn deflate_2_bits_strategy_0(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_2_should_be_palette_2.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| deflate(png.raw.data.as_ref(), 12, None));
+    b.iter(|| {
+        let min = AtomicMin::new(None);
+        deflate(png.raw_data.as_ref(), 9, 0, 15, &min)
+    });
 }
 
 #[bench]
-fn deflate_1_bits(b: &mut Bencher) {
+fn deflate_1_bits_strategy_0(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_1_should_be_palette_1.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| deflate(png.raw.data.as_ref(), 12, None));
+    b.iter(|| {
+        let min = AtomicMin::new(None);
+        deflate(png.raw_data.as_ref(), 9, 0, 15, &min)
+    });
+}
+
+#[bench]
+fn deflate_16_bits_strategy_1(b: &mut Bencher) {
+    let input = test::black_box(PathBuf::from("tests/files/rgb_16_should_be_rgb_16.png"));
+    let png = PngData::new(&input, false).unwrap();
+
+    b.iter(|| {
+        let min = AtomicMin::new(None);
+        deflate(png.raw_data.as_ref(), 9, 1, 15, &min)
+    });
+}
+
+#[bench]
+fn deflate_8_bits_strategy_1(b: &mut Bencher) {
+    let input = test::black_box(PathBuf::from("tests/files/rgb_8_should_be_rgb_8.png"));
+    let png = PngData::new(&input, false).unwrap();
+
+    b.iter(|| {
+        let min = AtomicMin::new(None);
+        deflate(png.raw_data.as_ref(), 9, 1, 15, &min)
+    });
+}
+
+#[bench]
+fn deflate_4_bits_strategy_1(b: &mut Bencher) {
+    let input = test::black_box(PathBuf::from(
+        "tests/files/palette_4_should_be_palette_4.png",
+    ));
+    let png = PngData::new(&input, false).unwrap();
+
+    b.iter(|| {
+        let min = AtomicMin::new(None);
+        deflate(png.raw_data.as_ref(), 9, 1, 15, &min)
+    });
+}
+
+#[bench]
+fn deflate_2_bits_strategy_1(b: &mut Bencher) {
+    let input = test::black_box(PathBuf::from(
+        "tests/files/palette_2_should_be_palette_2.png",
+    ));
+    let png = PngData::new(&input, false).unwrap();
+
+    b.iter(|| {
+        let min = AtomicMin::new(None);
+        deflate(png.raw_data.as_ref(), 9, 1, 15, &min)
+    });
+}
+
+#[bench]
+fn deflate_1_bits_strategy_1(b: &mut Bencher) {
+    let input = test::black_box(PathBuf::from(
+        "tests/files/palette_1_should_be_palette_1.png",
+    ));
+    let png = PngData::new(&input, false).unwrap();
+
+    b.iter(|| {
+        let min = AtomicMin::new(None);
+        deflate(png.raw_data.as_ref(), 9, 1, 15, &min)
+    });
+}
+
+#[bench]
+fn deflate_16_bits_strategy_2(b: &mut Bencher) {
+    let input = test::black_box(PathBuf::from("tests/files/rgb_16_should_be_rgb_16.png"));
+    let png = PngData::new(&input, false).unwrap();
+
+    b.iter(|| {
+        let min = AtomicMin::new(None);
+        deflate(png.raw_data.as_ref(), 9, 2, 15, &min)
+    });
+}
+
+#[bench]
+fn deflate_8_bits_strategy_2(b: &mut Bencher) {
+    let input = test::black_box(PathBuf::from("tests/files/rgb_8_should_be_rgb_8.png"));
+    let png = PngData::new(&input, false).unwrap();
+
+    b.iter(|| {
+        let min = AtomicMin::new(None);
+        deflate(png.raw_data.as_ref(), 9, 2, 15, &min)
+    });
+}
+
+#[bench]
+fn deflate_4_bits_strategy_2(b: &mut Bencher) {
+    let input = test::black_box(PathBuf::from(
+        "tests/files/palette_4_should_be_palette_4.png",
+    ));
+    let png = PngData::new(&input, false).unwrap();
+
+    b.iter(|| {
+        let min = AtomicMin::new(None);
+        deflate(png.raw_data.as_ref(), 9, 2, 15, &min)
+    });
+}
+
+#[bench]
+fn deflate_2_bits_strategy_2(b: &mut Bencher) {
+    let input = test::black_box(PathBuf::from(
+        "tests/files/palette_2_should_be_palette_2.png",
+    ));
+    let png = PngData::new(&input, false).unwrap();
+
+    b.iter(|| {
+        let min = AtomicMin::new(None);
+        deflate(png.raw_data.as_ref(), 9, 2, 15, &min)
+    });
+}
+
+#[bench]
+fn deflate_1_bits_strategy_2(b: &mut Bencher) {
+    let input = test::black_box(PathBuf::from(
+        "tests/files/palette_1_should_be_palette_1.png",
+    ));
+    let png = PngData::new(&input, false).unwrap();
+
+    b.iter(|| {
+        let min = AtomicMin::new(None);
+        deflate(png.raw_data.as_ref(), 9, 2, 15, &min)
+    });
+}
+
+#[bench]
+fn deflate_16_bits_strategy_3(b: &mut Bencher) {
+    let input = test::black_box(PathBuf::from("tests/files/rgb_16_should_be_rgb_16.png"));
+    let png = PngData::new(&input, false).unwrap();
+
+    b.iter(|| {
+        let min = AtomicMin::new(None);
+        deflate(png.raw_data.as_ref(), 9, 3, 15, &min)
+    });
+}
+
+#[bench]
+fn deflate_8_bits_strategy_3(b: &mut Bencher) {
+    let input = test::black_box(PathBuf::from("tests/files/rgb_8_should_be_rgb_8.png"));
+    let png = PngData::new(&input, false).unwrap();
+
+    b.iter(|| {
+        let min = AtomicMin::new(None);
+        deflate(png.raw_data.as_ref(), 9, 3, 15, &min)
+    });
+}
+
+#[bench]
+fn deflate_4_bits_strategy_3(b: &mut Bencher) {
+    let input = test::black_box(PathBuf::from(
+        "tests/files/palette_4_should_be_palette_4.png",
+    ));
+    let png = PngData::new(&input, false).unwrap();
+
+    b.iter(|| {
+        let min = AtomicMin::new(None);
+        deflate(png.raw_data.as_ref(), 9, 3, 15, &min)
+    });
+}
+
+#[bench]
+fn deflate_2_bits_strategy_3(b: &mut Bencher) {
+    let input = test::black_box(PathBuf::from(
+        "tests/files/palette_2_should_be_palette_2.png",
+    ));
+    let png = PngData::new(&input, false).unwrap();
+
+    b.iter(|| {
+        let min = AtomicMin::new(None);
+        deflate(png.raw_data.as_ref(), 9, 3, 15, &min)
+    });
+}
+
+#[bench]
+fn deflate_1_bits_strategy_3(b: &mut Bencher) {
+    let input = test::black_box(PathBuf::from(
+        "tests/files/palette_1_should_be_palette_1.png",
+    ));
+    let png = PngData::new(&input, false).unwrap();
+
+    b.iter(|| {
+        let min = AtomicMin::new(None);
+        deflate(png.raw_data.as_ref(), 9, 3, 15, &min)
+    });
 }
 
 #[bench]
 fn inflate_generic(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_16_should_be_rgb_16.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| inflate(png.idat_data.as_ref(), png.raw.ihdr.raw_data_size()));
+    b.iter(|| inflate(png.idat_data.as_ref()));
 }

benches/filters.rs

@@ -3,25 +3,28 @@
 extern crate oxipng;
 extern crate test;
 
+use oxipng::internal_tests::*;
 use std::path::PathBuf;
-
-use oxipng::{internal_tests::*, *};
 use test::Bencher;
 
 #[bench]
 fn filters_16_bits_filter_0(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_16_should_be_rgb_16.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::NONE, false));
+    b.iter(|| {
+        png.filter_image(0);
+    });
 }
 
 #[bench]
 fn filters_8_bits_filter_0(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_8_should_be_rgb_8.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::NONE, false));
+    b.iter(|| {
+        png.filter_image(0);
+    });
 }
 
 #[bench]
@@ -29,9 +32,11 @@ fn filters_4_bits_filter_0(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_4_should_be_palette_4.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::NONE, false));
+    b.iter(|| {
+        png.filter_image(0);
+    });
 }
 
 #[bench]
@@ -39,9 +44,11 @@ fn filters_2_bits_filter_0(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_2_should_be_palette_2.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::NONE, false));
+    b.iter(|| {
+        png.filter_image(0);
+    });
 }
 
 #[bench]
@@ -49,25 +56,31 @@ fn filters_1_bits_filter_0(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_1_should_be_palette_1.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::NONE, false));
+    b.iter(|| {
+        png.filter_image(0);
+    });
 }
 
 #[bench]
 fn filters_16_bits_filter_1(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_16_should_be_rgb_16.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::SUB, false));
+    b.iter(|| {
+        png.filter_image(1);
+    });
 }
 
 #[bench]
 fn filters_8_bits_filter_1(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_8_should_be_rgb_8.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::SUB, false));
+    b.iter(|| {
+        png.filter_image(1);
+    });
 }
 
 #[bench]
@@ -75,9 +88,11 @@ fn filters_4_bits_filter_1(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_4_should_be_palette_4.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::SUB, false));
+    b.iter(|| {
+        png.filter_image(1);
+    });
 }
 
 #[bench]
@@ -85,9 +100,11 @@ fn filters_2_bits_filter_1(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_2_should_be_palette_2.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::SUB, false));
+    b.iter(|| {
+        png.filter_image(1);
+    });
 }
 
 #[bench]
@@ -95,25 +112,31 @@ fn filters_1_bits_filter_1(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_1_should_be_palette_1.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::SUB, false));
+    b.iter(|| {
+        png.filter_image(1);
+    });
 }
 
 #[bench]
 fn filters_16_bits_filter_2(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_16_should_be_rgb_16.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::UP, false));
+    b.iter(|| {
+        png.filter_image(2);
+    });
 }
 
 #[bench]
 fn filters_8_bits_filter_2(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_8_should_be_rgb_8.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::UP, false));
+    b.iter(|| {
+        png.filter_image(2);
+    });
 }
 
 #[bench]
@@ -121,9 +144,11 @@ fn filters_4_bits_filter_2(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_4_should_be_palette_4.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::UP, false));
+    b.iter(|| {
+        png.filter_image(2);
+    });
 }
 
 #[bench]
@@ -131,9 +156,11 @@ fn filters_2_bits_filter_2(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_2_should_be_palette_2.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::UP, false));
+    b.iter(|| {
+        png.filter_image(2);
+    });
 }
 
 #[bench]
@@ -141,25 +168,31 @@ fn filters_1_bits_filter_2(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_1_should_be_palette_1.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::UP, false));
+    b.iter(|| {
+        png.filter_image(2);
+    });
 }
 
 #[bench]
 fn filters_16_bits_filter_3(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_16_should_be_rgb_16.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::AVERAGE, false));
+    b.iter(|| {
+        png.filter_image(3);
+    });
 }
 
 #[bench]
 fn filters_8_bits_filter_3(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_8_should_be_rgb_8.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::AVERAGE, false));
+    b.iter(|| {
+        png.filter_image(3);
+    });
 }
 
 #[bench]
@@ -167,9 +200,11 @@ fn filters_4_bits_filter_3(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_4_should_be_palette_4.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::AVERAGE, false));
+    b.iter(|| {
+        png.filter_image(3);
+    });
 }
 
 #[bench]
@@ -177,9 +212,11 @@ fn filters_2_bits_filter_3(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_2_should_be_palette_2.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::AVERAGE, false));
+    b.iter(|| {
+        png.filter_image(3);
+    });
 }
 
 #[bench]
@@ -187,25 +224,31 @@ fn filters_1_bits_filter_3(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_1_should_be_palette_1.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::AVERAGE, false));
+    b.iter(|| {
+        png.filter_image(3);
+    });
 }
 
 #[bench]
 fn filters_16_bits_filter_4(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_16_should_be_rgb_16.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::PAETH, false));
+    b.iter(|| {
+        png.filter_image(4);
+    });
 }
 
 #[bench]
 fn filters_8_bits_filter_4(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_8_should_be_rgb_8.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::PAETH, false));
+    b.iter(|| {
+        png.filter_image(4);
+    });
 }
 
 #[bench]
@@ -213,9 +256,11 @@ fn filters_4_bits_filter_4(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_4_should_be_palette_4.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::PAETH, false));
+    b.iter(|| {
+        png.filter_image(4);
+    });
 }
 
 #[bench]
@@ -223,9 +268,11 @@ fn filters_2_bits_filter_4(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_2_should_be_palette_2.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::PAETH, false));
+    b.iter(|| {
+        png.filter_image(4);
+    });
 }
 
 #[bench]
@@ -233,25 +280,31 @@ fn filters_1_bits_filter_4(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_1_should_be_palette_1.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::PAETH, false));
+    b.iter(|| {
+        png.filter_image(4);
+    });
 }
 
 #[bench]
 fn filters_16_bits_filter_5(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_16_should_be_rgb_16.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::MinSum, false));
+    b.iter(|| {
+        png.filter_image(5);
+    });
 }
 
 #[bench]
 fn filters_8_bits_filter_5(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_8_should_be_rgb_8.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::MinSum, false));
+    b.iter(|| {
+        png.filter_image(5);
+    });
 }
 
 #[bench]
@@ -259,9 +312,11 @@ fn filters_4_bits_filter_5(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_4_should_be_palette_4.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::MinSum, false));
+    b.iter(|| {
+        png.filter_image(5);
+    });
 }
 
 #[bench]
@@ -269,9 +324,11 @@ fn filters_2_bits_filter_5(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_2_should_be_palette_2.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::MinSum, false));
+    b.iter(|| {
+        png.filter_image(5);
+    });
 }
 
 #[bench]
@@ -279,7 +336,9 @@ fn filters_1_bits_filter_5(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_1_should_be_palette_1.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.filter_image(FilterStrategy::MinSum, false));
+    b.iter(|| {
+        png.filter_image(5);
+    });
 }

benches/interlacing.rs

@@ -3,25 +3,30 @@
 extern crate oxipng;
 extern crate test;
 
+use oxipng::internal_tests::*;
 use std::path::PathBuf;
-
-use oxipng::{internal_tests::*, *};
 use test::Bencher;
 
 #[bench]
 fn interlacing_16_bits(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_16_should_be_rgb_16.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(true));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.change_interlacing(1);
+    });
 }
 
 #[bench]
 fn interlacing_8_bits(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_8_should_be_rgb_8.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(true));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.change_interlacing(1);
+    });
 }
 
 #[bench]
@@ -29,9 +34,12 @@ fn interlacing_4_bits(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_4_should_be_palette_4.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(true));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.change_interlacing(1);
+    });
 }
 
 #[bench]
@@ -39,9 +47,12 @@ fn interlacing_2_bits(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_2_should_be_palette_2.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(true));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.change_interlacing(1);
+    });
 }
 
 #[bench]
@@ -49,9 +60,12 @@ fn interlacing_1_bits(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_1_should_be_palette_1.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(true));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.change_interlacing(1);
+    });
 }
 
 #[bench]
@@ -59,9 +73,12 @@ fn deinterlacing_16_bits(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/interlaced_rgb_16_should_be_rgb_16.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(false));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.change_interlacing(0);
+    });
 }
 
 #[bench]
@@ -69,9 +86,12 @@ fn deinterlacing_8_bits(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/interlaced_rgb_8_should_be_rgb_8.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(false));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.change_interlacing(0);
+    });
 }
 
 #[bench]
@@ -79,9 +99,12 @@ fn deinterlacing_4_bits(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/interlaced_palette_4_should_be_palette_4.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(false));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.change_interlacing(0);
+    });
 }
 
 #[bench]
@@ -89,9 +112,12 @@ fn deinterlacing_2_bits(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/interlaced_palette_2_should_be_palette_2.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(false));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.change_interlacing(0);
+    });
 }
 
 #[bench]
@@ -99,7 +125,10 @@ fn deinterlacing_1_bits(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/interlaced_palette_1_should_be_palette_1.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(false));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.change_interlacing(0);
+    });
 }

benches/reductions.rs

@@ -3,25 +3,19 @@
 extern crate oxipng;
 extern crate test;
 
+use oxipng::internal_tests::*;
 use std::path::PathBuf;
-
-use oxipng::{internal_tests::*, *};
 use test::Bencher;
 
 #[bench]
 fn reductions_16_to_8_bits(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_16_should_be_rgb_8.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| bit_depth::reduced_bit_depth_16_to_8(&png.raw, false));
+    b.iter(|| {
-}
+        let mut safe_png = png.clone();
-
+        safe_png.reduce_bit_depth();
-#[bench]
+    });
-fn reductions_16_to_8_bits_scaled(b: &mut Bencher) {
-    let input = test::black_box(PathBuf::from("tests/files/rgb_16_should_be_rgb_16.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
-
-    b.iter(|| bit_depth::reduced_bit_depth_16_to_8(&png.raw, true));
 }
 
 #[bench]
@@ -29,9 +23,12 @@ fn reductions_8_to_4_bits(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_8_should_be_palette_4.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| bit_depth::reduced_bit_depth_8_or_less(&png.raw));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.reduce_bit_depth();
+    });
 }
 
 #[bench]
@@ -39,9 +36,12 @@ fn reductions_8_to_2_bits(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_8_should_be_palette_2.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| bit_depth::reduced_bit_depth_8_or_less(&png.raw));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.reduce_bit_depth();
+    });
 }
 
 #[bench]
@@ -49,63 +49,73 @@ fn reductions_8_to_1_bits(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_8_should_be_palette_1.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| bit_depth::reduced_bit_depth_8_or_less(&png.raw));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.reduce_bit_depth();
+    });
 }
 
 #[bench]
-fn reductions_grayscale_8_to_4_bits(b: &mut Bencher) {
+fn reductions_4_to_2_bits(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
-        "tests/files/grayscale_8_should_be_grayscale_4.png",
+        "tests/files/palette_4_should_be_palette_2.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| bit_depth::reduced_bit_depth_8_or_less(&png.raw));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.reduce_bit_depth();
+    });
 }
 
 #[bench]
-fn reductions_grayscale_8_to_2_bits(b: &mut Bencher) {
+fn reductions_4_to_1_bits(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
-        "tests/files/grayscale_8_should_be_grayscale_2.png",
+        "tests/files/palette_4_should_be_palette_1.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| bit_depth::reduced_bit_depth_8_or_less(&png.raw));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.reduce_bit_depth();
+    });
 }
 
 #[bench]
-fn reductions_grayscale_8_to_1_bits(b: &mut Bencher) {
+fn reductions_2_to_1_bits(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
-        "tests/files/grayscale_8_should_be_grayscale_1.png",
+        "tests/files/palette_2_should_be_palette_1.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| bit_depth::reduced_bit_depth_8_or_less(&png.raw));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.reduce_bit_depth();
+    });
 }
 
 #[bench]
 fn reductions_rgba_to_rgb_16(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgba_16_should_be_rgb_16.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| alpha::reduced_alpha_channel(&png.raw, true));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.reduce_color_type();
+    });
 }
 
 #[bench]
 fn reductions_rgba_to_rgb_8(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgba_8_should_be_rgb_8.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| alpha::reduced_alpha_channel(&png.raw, true));
+    b.iter(|| {
-}
+        let mut safe_png = png.clone();
-
+        safe_png.reduce_color_type();
-#[bench]
+    });
-fn reductions_rgba_to_rgb_trns_8(b: &mut Bencher) {
-    let input = test::black_box(PathBuf::from("tests/files/rgba_8_should_be_rgb_trns_8.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
-
-    b.iter(|| alpha::reduced_alpha_channel(&png.raw, true));
 }
 
 #[bench]
@@ -113,9 +123,12 @@ fn reductions_rgba_to_grayscale_alpha_16(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/rgba_16_should_be_grayscale_alpha_16.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| color::reduced_rgb_to_grayscale(&png.raw));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.reduce_color_type();
+    });
 }
 
 #[bench]
@@ -123,9 +136,38 @@ fn reductions_rgba_to_grayscale_alpha_8(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/rgba_8_should_be_grayscale_alpha_8.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| color::reduced_rgb_to_grayscale(&png.raw));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.reduce_color_type();
+    });
+}
+
+#[bench]
+fn reductions_rgba_to_grayscale_16(b: &mut Bencher) {
+    let input = test::black_box(PathBuf::from(
+        "tests/files/rgba_16_should_be_grayscale_16.png",
+    ));
+    let png = PngData::new(&input, false).unwrap();
+
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.reduce_color_type();
+    });
+}
+
+#[bench]
+fn reductions_rgba_to_grayscale_8(b: &mut Bencher) {
+    let input = test::black_box(PathBuf::from(
+        "tests/files/rgba_8_should_be_grayscale_8.png",
+    ));
+    let png = PngData::new(&input, false).unwrap();
+
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.reduce_color_type();
+    });
 }
 
 #[bench]
@@ -133,83 +175,45 @@ fn reductions_rgb_to_grayscale_16(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/rgb_16_should_be_grayscale_16.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| color::reduced_rgb_to_grayscale(&png.raw));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.reduce_color_type();
+    });
 }
 
 #[bench]
 fn reductions_rgb_to_grayscale_8(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_8_should_be_grayscale_8.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| color::reduced_rgb_to_grayscale(&png.raw));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.reduce_color_type();
+    });
 }
 
 #[bench]
 fn reductions_rgba_to_palette_8(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgba_8_should_be_palette_8.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| color::reduced_to_indexed(&png.raw, true));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.reduce_color_type();
+    });
 }
 
 #[bench]
 fn reductions_rgb_to_palette_8(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_8_should_be_palette_8.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| color::reduced_to_indexed(&png.raw, true));
+    b.iter(|| {
-}
+        let mut safe_png = png.clone();
-
+        safe_png.reduce_color_type();
-#[bench]
+    });
-fn reductions_grayscale_alpha_to_grayscale_16(b: &mut Bencher) {
-    let input = test::black_box(PathBuf::from(
-        "tests/files/grayscale_alpha_16_should_be_grayscale_16.png",
-    ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
-
-    b.iter(|| alpha::reduced_alpha_channel(&png.raw, true));
-}
-
-#[bench]
-fn reductions_grayscale_alpha_to_grayscale_8(b: &mut Bencher) {
-    let input = test::black_box(PathBuf::from(
-        "tests/files/grayscale_alpha_8_should_be_grayscale_8.png",
-    ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
-
-    b.iter(|| alpha::reduced_alpha_channel(&png.raw, true));
-}
-
-#[bench]
-fn reductions_grayscale_alpha_to_grayscale_trns_8(b: &mut Bencher) {
-    let input = test::black_box(PathBuf::from(
-        "tests/files/grayscale_alpha_8_should_be_grayscale_trns_8.png",
-    ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
-
-    b.iter(|| alpha::reduced_alpha_channel(&png.raw, true));
-}
-
-#[bench]
-fn reductions_grayscale_8_to_palette_8(b: &mut Bencher) {
-    let input = test::black_box(PathBuf::from(
-        "tests/files/grayscale_8_should_be_palette_8.png",
-    ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
-
-    b.iter(|| color::reduced_to_indexed(&png.raw, true));
-}
-
-#[bench]
-fn reductions_palette_8_to_grayscale_8(b: &mut Bencher) {
-    let input = test::black_box(PathBuf::from(
-        "tests/files/palette_8_should_be_grayscale_8.png",
-    ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
-
-    b.iter(|| color::indexed_to_channels(&png.raw, true, false));
 }
 
 #[bench]
@@ -217,9 +221,12 @@ fn reductions_palette_duplicate_reduction(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_should_be_reduced_with_dupes.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| palette::reduced_palette(&png.raw, false));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.reduce_palette();
+    });
 }
 
 #[bench]
@@ -227,9 +234,12 @@ fn reductions_palette_unused_reduction(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_should_be_reduced_with_unused.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| palette::reduced_palette(&png.raw, false));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.reduce_palette();
+    });
 }
 
 #[bench]
@@ -237,45 +247,76 @@ fn reductions_palette_full_reduction(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_should_be_reduced_with_both.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| palette::reduced_palette(&png.raw, false));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.reduce_palette();
+    });
 }
 
 #[bench]
-fn reductions_palette_sort(b: &mut Bencher) {
+fn reductions_alpha_black(b: &mut Bencher) {
-    let input = test::black_box(PathBuf::from(
+    let input = test::black_box(PathBuf::from("tests/files/rgba_8_reduce_alpha_black.png"));
-        "tests/files/palette_8_should_be_palette_8.png",
+    let png = PngData::new(&input, false).unwrap();
-    ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| palette::sorted_palette(&png.raw));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.reduce_alpha_channel(AlphaOptim::Black);
+    });
 }
 
 #[bench]
-fn reductions_palette_sort_mzeng(b: &mut Bencher) {
+fn reductions_alpha_white(b: &mut Bencher) {
-    let input = test::black_box(PathBuf::from(
+    let input = test::black_box(PathBuf::from("tests/files/rgba_8_reduce_alpha_white.png"));
-        "tests/files/palette_8_should_be_palette_8.png",
+    let png = PngData::new(&input, false).unwrap();
-    ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| palette::sorted_palette_mzeng(&png.raw));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.reduce_alpha_channel(AlphaOptim::White);
+    });
 }
 
 #[bench]
-fn reductions_palette_sort_battiato(b: &mut Bencher) {
+fn reductions_alpha_left(b: &mut Bencher) {
-    let input = test::black_box(PathBuf::from(
+    let input = test::black_box(PathBuf::from("tests/files/rgba_8_reduce_alpha_left.png"));
-        "tests/files/palette_8_should_be_palette_8.png",
+    let png = PngData::new(&input, false).unwrap();
-    ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| palette::sorted_palette_battiato(&png.raw));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.reduce_alpha_channel(AlphaOptim::Left);
+    });
 }
 
 #[bench]
-fn reductions_alpha(b: &mut Bencher) {
+fn reductions_alpha_right(b: &mut Bencher) {
-    let input = test::black_box(PathBuf::from("tests/files/rgba_8_reduce_alpha.png"));
+    let input = test::black_box(PathBuf::from("tests/files/rgba_8_reduce_alpha_right.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
-    b.iter(|| alpha::cleaned_alpha_channel(&png.raw));
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.reduce_alpha_channel(AlphaOptim::Right);
+    });
+}
+
+#[bench]
+fn reductions_alpha_up(b: &mut Bencher) {
+    let input = test::black_box(PathBuf::from("tests/files/rgba_8_reduce_alpha_up.png"));
+    let png = PngData::new(&input, false).unwrap();
+
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.reduce_alpha_channel(AlphaOptim::Up);
+    });
+}
+
+#[bench]
+fn reductions_alpha_down(b: &mut Bencher) {
+    let input = test::black_box(PathBuf::from("tests/files/rgba_8_reduce_alpha_down.png"));
+    let png = PngData::new(&input, false).unwrap();
+
+    b.iter(|| {
+        let mut safe_png = png.clone();
+        safe_png.reduce_alpha_channel(AlphaOptim::Down);
+    });
 }

benches/strategies.rs

@@ -1,57 +0,0 @@
-#![feature(test)]
-
-extern crate oxipng;
-extern crate test;
-
-use std::path::PathBuf;
-
-use oxipng::{internal_tests::*, *};
-use test::Bencher;
-
-#[bench]
-fn filters_minsum(b: &mut Bencher) {
-    let input = test::black_box(PathBuf::from("tests/files/rgb_8_should_be_rgb_8.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
-
-    b.iter(|| png.raw.filter_image(FilterStrategy::MinSum, false));
-}
-
-#[bench]
-fn filters_entropy(b: &mut Bencher) {
-    let input = test::black_box(PathBuf::from("tests/files/rgb_8_should_be_rgb_8.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
-
-    b.iter(|| png.raw.filter_image(FilterStrategy::Entropy, false));
-}
-
-#[bench]
-fn filters_bigrams(b: &mut Bencher) {
-    let input = test::black_box(PathBuf::from("tests/files/rgb_8_should_be_rgb_8.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
-
-    b.iter(|| png.raw.filter_image(FilterStrategy::Bigrams, false));
-}
-
-#[bench]
-fn filters_bigent(b: &mut Bencher) {
-    let input = test::black_box(PathBuf::from("tests/files/rgb_8_should_be_rgb_8.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
-
-    b.iter(|| png.raw.filter_image(FilterStrategy::BigEnt, false));
-}
-
-#[bench]
-fn filters_brute(b: &mut Bencher) {
-    let input = test::black_box(PathBuf::from("tests/files/rgb_8_should_be_rgb_8.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
-
-    b.iter(|| {
-        png.raw.filter_image(
-            FilterStrategy::Brute {
-                num_lines: 4,
-                level: 1,
-            },
-            false,
-        )
-    });
-}

benches/zopfli.rs

@@ -3,28 +3,27 @@
 extern crate oxipng;
 extern crate test;
 
+use oxipng::internal_tests::*;
 use std::path::PathBuf;
-
-use oxipng::{internal_tests::*, *};
 use test::Bencher;
 
 #[bench]
 fn zopfli_16_bits_strategy_0(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_16_should_be_rgb_16.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
     b.iter(|| {
-        zopfli_deflate(png.raw.data.as_ref(), ZopfliOptions::default()).ok();
+        zopfli_deflate(png.raw_data.as_ref()).ok();
     });
 }
 
 #[bench]
 fn zopfli_8_bits_strategy_0(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_8_should_be_rgb_8.png"));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
     b.iter(|| {
-        zopfli_deflate(png.raw.data.as_ref(), ZopfliOptions::default()).ok();
+        zopfli_deflate(png.raw_data.as_ref()).ok();
     });
 }
 
@@ -33,10 +32,10 @@ fn zopfli_4_bits_strategy_0(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_4_should_be_palette_4.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
     b.iter(|| {
-        zopfli_deflate(png.raw.data.as_ref(), ZopfliOptions::default()).ok();
+        zopfli_deflate(png.raw_data.as_ref()).ok();
     });
 }
 
@@ -45,10 +44,10 @@ fn zopfli_2_bits_strategy_0(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_2_should_be_palette_2.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
     b.iter(|| {
-        zopfli_deflate(png.raw.data.as_ref(), ZopfliOptions::default()).ok();
+        zopfli_deflate(png.raw_data.as_ref()).ok();
     });
 }
 
@@ -57,9 +56,9 @@ fn zopfli_1_bits_strategy_0(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
         "tests/files/palette_1_should_be_palette_1.png",
     ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
+    let png = PngData::new(&input, false).unwrap();
 
     b.iter(|| {
-        zopfli_deflate(png.raw.data.as_ref(), ZopfliOptions::default()).ok();
+        zopfli_deflate(png.raw_data.as_ref()).ok();
     });
 }

index.html

@@ -0,0 +1 @@
+<script>(function() {window.location.assign(window.location.href + "doc/oxipng/");})();</script>

package-lock.json

@@ -0,0 +1,386 @@
+{
+  "name": "oxipng",
+  "version": "1.0.0",
+  "lockfileVersion": 1,
+  "requires": true,
+  "dependencies": {
+    "ansi-regex": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/ansi-regex/-/ansi-regex-3.0.0.tgz",
+      "integrity": "sha1-7QMXwyIGT3lGbAKWa922Bas32Zg=",
+      "dev": true
+    },
+    "array-find-index": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/array-find-index/-/array-find-index-1.0.2.tgz",
+      "integrity": "sha1-3wEKoSh+Fku9pvlyOwqWoexBh6E=",
+      "dev": true
+    },
+    "builtin-modules": {
+      "version": "1.1.1",
+      "resolved": "https://registry.npmjs.org/builtin-modules/-/builtin-modules-1.1.1.tgz",
+      "integrity": "sha1-Jw8HbFpywC9bZaR9+Uxf46J4iS8=",
+      "dev": true
+    },
+    "camelcase": {
+      "version": "2.1.1",
+      "resolved": "https://registry.npmjs.org/camelcase/-/camelcase-2.1.1.tgz",
+      "integrity": "sha1-fB0W1nmhu+WcoCys7PsBHiAfWh8=",
+      "dev": true
+    },
+    "camelcase-keys": {
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/camelcase-keys/-/camelcase-keys-2.1.0.tgz",
+      "integrity": "sha1-MIvur/3ygRkFHvodkyITyRuPkuc=",
+      "dev": true,
+      "requires": {
+        "camelcase": "^2.0.0",
+        "map-obj": "^1.0.0"
+      }
+    },
+    "currently-unhandled": {
+      "version": "0.4.1",
+      "resolved": "https://registry.npmjs.org/currently-unhandled/-/currently-unhandled-0.4.1.tgz",
+      "integrity": "sha1-mI3zP+qxke95mmE2nddsF635V+o=",
+      "dev": true,
+      "requires": {
+        "array-find-index": "^1.0.1"
+      }
+    },
+    "decamelize": {
+      "version": "1.2.0",
+      "resolved": "https://registry.npmjs.org/decamelize/-/decamelize-1.2.0.tgz",
+      "integrity": "sha1-9lNNFRSCabIDUue+4m9QH5oZEpA=",
+      "dev": true
+    },
+    "error-ex": {
+      "version": "1.3.1",
+      "resolved": "https://registry.npmjs.org/error-ex/-/error-ex-1.3.1.tgz",
+      "integrity": "sha1-+FWobOYa3E6GIcPNoh56dhLDqNw=",
+      "dev": true,
+      "requires": {
+        "is-arrayish": "^0.2.1"
+      }
+    },
+    "find-up": {
+      "version": "1.1.2",
+      "resolved": "https://registry.npmjs.org/find-up/-/find-up-1.1.2.tgz",
+      "integrity": "sha1-ay6YIrGizgpgq2TWEOzK1TyyTQ8=",
+      "dev": true,
+      "requires": {
+        "path-exists": "^2.0.0",
+        "pinkie-promise": "^2.0.0"
+      }
+    },
+    "get-stdin": {
+      "version": "4.0.1",
+      "resolved": "https://registry.npmjs.org/get-stdin/-/get-stdin-4.0.1.tgz",
+      "integrity": "sha1-uWjGsKBDhDJJAui/Gl3zJXmkUP4=",
+      "dev": true
+    },
+    "graceful-fs": {
+      "version": "4.1.11",
+      "resolved": "https://registry.npmjs.org/graceful-fs/-/graceful-fs-4.1.11.tgz",
+      "integrity": "sha1-Dovf5NHduIVNZOBOp8AOKgJuVlg=",
+      "dev": true
+    },
+    "hosted-git-info": {
+      "version": "2.5.0",
+      "resolved": "https://registry.npmjs.org/hosted-git-info/-/hosted-git-info-2.5.0.tgz",
+      "integrity": "sha512-pNgbURSuab90KbTqvRPsseaTxOJCZBD0a7t+haSN33piP9cCM4l0CqdzAif2hUqm716UovKB2ROmiabGAKVXyg==",
+      "dev": true
+    },
+    "indent-string": {
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/indent-string/-/indent-string-2.1.0.tgz",
+      "integrity": "sha1-ji1INIdCEhtKghi3oTfppSBJ3IA=",
+      "dev": true,
+      "requires": {
+        "repeating": "^2.0.0"
+      }
+    },
+    "is-arrayish": {
+      "version": "0.2.1",
+      "resolved": "https://registry.npmjs.org/is-arrayish/-/is-arrayish-0.2.1.tgz",
+      "integrity": "sha1-d8mYQFJ6qOyxqLppe4BkWnqSap0=",
+      "dev": true
+    },
+    "is-builtin-module": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/is-builtin-module/-/is-builtin-module-1.0.0.tgz",
+      "integrity": "sha1-VAVy0096wxGfj3bDDLwbHgN6/74=",
+      "dev": true,
+      "requires": {
+        "builtin-modules": "^1.0.0"
+      }
+    },
+    "is-finite": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/is-finite/-/is-finite-1.0.2.tgz",
+      "integrity": "sha1-zGZ3aVYCvlUO8R6LSqYwU0K20Ko=",
+      "dev": true,
+      "requires": {
+        "number-is-nan": "^1.0.0"
+      }
+    },
+    "is-utf8": {
+      "version": "0.2.1",
+      "resolved": "https://registry.npmjs.org/is-utf8/-/is-utf8-0.2.1.tgz",
+      "integrity": "sha1-Sw2hRCEE0bM2NA6AeX6GXPOffXI=",
+      "dev": true
+    },
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+      "resolved": "https://registry.npmjs.org/load-json-file/-/load-json-file-1.1.0.tgz",
+      "integrity": "sha1-lWkFcI1YtLq0wiYbBPWfMcmTdMA=",
+      "dev": true,
+      "requires": {
+        "graceful-fs": "^4.1.2",
+        "parse-json": "^2.2.0",
+        "pify": "^2.0.0",
+        "pinkie-promise": "^2.0.0",
+        "strip-bom": "^2.0.0"
+      }
+    },
+    "loud-rejection": {
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+      "integrity": "sha1-W0b4AUft7leIcPCG0Eghz5mOVR8=",
+      "dev": true,
+      "requires": {
+        "currently-unhandled": "^0.4.1",
+        "signal-exit": "^3.0.0"
+      }
+    },
+    "map-obj": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/map-obj/-/map-obj-1.0.1.tgz",
+      "integrity": "sha1-2TPOuSBdgr3PSIb2dCvcK03qFG0=",
+      "dev": true
+    },
+    "meow": {
+      "version": "3.7.0",
+      "resolved": "https://registry.npmjs.org/meow/-/meow-3.7.0.tgz",
+      "integrity": "sha1-cstmi0JSKCkKu/qFaJJYcwioAfs=",
+      "dev": true,
+      "requires": {
+        "camelcase-keys": "^2.0.0",
+        "decamelize": "^1.1.2",
+        "loud-rejection": "^1.0.0",
+        "map-obj": "^1.0.1",
+        "minimist": "^1.1.3",
+        "normalize-package-data": "^2.3.4",
+        "object-assign": "^4.0.1",
+        "read-pkg-up": "^1.0.1",
+        "redent": "^1.0.0",
+        "trim-newlines": "^1.0.0"
+      }
+    },
+    "minimist": {
+      "version": "1.2.0",
+      "resolved": "https://registry.npmjs.org/minimist/-/minimist-1.2.0.tgz",
+      "integrity": "sha1-o1AIsg9BOD7sH7kU9M1d95omQoQ=",
+      "dev": true
+    },
+    "normalize-package-data": {
+      "version": "2.4.0",
+      "resolved": "https://registry.npmjs.org/normalize-package-data/-/normalize-package-data-2.4.0.tgz",
+      "integrity": "sha512-9jjUFbTPfEy3R/ad/2oNbKtW9Hgovl5O1FvFWKkKblNXoN/Oou6+9+KKohPK13Yc3/TyunyWhJp6gvRNR/PPAw==",
+      "dev": true,
+      "requires": {
+        "hosted-git-info": "^2.1.4",
+        "is-builtin-module": "^1.0.0",
+        "semver": "2 || 3 || 4 || 5",
+        "validate-npm-package-license": "^3.0.1"
+      }
+    },
+    "number-is-nan": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/number-is-nan/-/number-is-nan-1.0.1.tgz",
+      "integrity": "sha1-CXtgK1NCKlIsGvuHkDGDNpQaAR0=",
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+    },
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+      "integrity": "sha1-IQmtx5ZYh8/AXLvUQsrIv7s2CGM=",
+      "dev": true
+    },
+    "parse-json": {
+      "version": "2.2.0",
+      "resolved": "https://registry.npmjs.org/parse-json/-/parse-json-2.2.0.tgz",
+      "integrity": "sha1-9ID0BDTvgHQfhGkJn43qGPVaTck=",
+      "dev": true,
+      "requires": {
+        "error-ex": "^1.2.0"
+      }
+    },
+    "path-exists": {
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/path-exists/-/path-exists-2.1.0.tgz",
+      "integrity": "sha1-D+tsZPD8UY2adU3V77YscCJ2H0s=",
+      "dev": true,
+      "requires": {
+        "pinkie-promise": "^2.0.0"
+      }
+    },
+    "path-type": {
+      "version": "1.1.0",
+      "resolved": "https://registry.npmjs.org/path-type/-/path-type-1.1.0.tgz",
+      "integrity": "sha1-WcRPfuSR2nBNpBXaWkBwuk+P5EE=",
+      "dev": true,
+      "requires": {
+        "graceful-fs": "^4.1.2",
+        "pify": "^2.0.0",
+        "pinkie-promise": "^2.0.0"
+      }
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+      "integrity": "sha1-7RQaasBDqEnqWISY59yosVMw6Qw=",
+      "dev": true
+    },
+    "pinkie": {
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+      "resolved": "https://registry.npmjs.org/pinkie/-/pinkie-2.0.4.tgz",
+      "integrity": "sha1-clVrgM+g1IqXToDnckjoDtT3+HA=",
+      "dev": true
+    },
+    "pinkie-promise": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/pinkie-promise/-/pinkie-promise-2.0.1.tgz",
+      "integrity": "sha1-ITXW36ejWMBprJsXh3YogihFD/o=",
+      "dev": true,
+      "requires": {
+        "pinkie": "^2.0.0"
+      }
+    },
+    "read-pkg": {
+      "version": "1.1.0",
+      "resolved": "https://registry.npmjs.org/read-pkg/-/read-pkg-1.1.0.tgz",
+      "integrity": "sha1-9f+qXs0pyzHAR0vKfXVra7KePyg=",
+      "dev": true,
+      "requires": {
+        "load-json-file": "^1.0.0",
+        "normalize-package-data": "^2.3.2",
+        "path-type": "^1.0.0"
+      }
+    },
+    "read-pkg-up": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/read-pkg-up/-/read-pkg-up-1.0.1.tgz",
+      "integrity": "sha1-nWPBMnbAZZGNV/ACpX9AobZD+wI=",
+      "dev": true,
+      "requires": {
+        "find-up": "^1.0.0",
+        "read-pkg": "^1.0.0"
+      }
+    },
+    "redent": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/redent/-/redent-1.0.0.tgz",
+      "integrity": "sha1-z5Fqsf1fHxbfsggi3W7H9zDCr94=",
+      "dev": true,
+      "requires": {
+        "indent-string": "^2.1.0",
+        "strip-indent": "^1.0.1"
+      }
+    },
+    "repeating": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/repeating/-/repeating-2.0.1.tgz",
+      "integrity": "sha1-UhTFOpJtNVJwdSf7q0FdvAjQbdo=",
+      "dev": true,
+      "requires": {
+        "is-finite": "^1.0.0"
+      }
+    },
+    "semver": {
+      "version": "5.5.0",
+      "resolved": "https://registry.npmjs.org/semver/-/semver-5.5.0.tgz",
+      "integrity": "sha512-4SJ3dm0WAwWy/NVeioZh5AntkdJoWKxHxcmyP622fOkgHa4z3R0TdBJICINyaSDE6uNwVc8gZr+ZinwZAH4xIA==",
+      "dev": true
+    },
+    "signal-exit": {
+      "version": "3.0.2",
+      "resolved": "https://registry.npmjs.org/signal-exit/-/signal-exit-3.0.2.tgz",
+      "integrity": "sha1-tf3AjxKH6hF4Yo5BXiUTK3NkbG0=",
+      "dev": true
+    },
+    "spdx-correct": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/spdx-correct/-/spdx-correct-1.0.2.tgz",
+      "integrity": "sha1-SzBz2TP/UfORLwOsVRlJikFQ20A=",
+      "dev": true,
+      "requires": {
+        "spdx-license-ids": "^1.0.2"
+      }
+    },
+    "spdx-expression-parse": {
+      "version": "1.0.4",
+      "resolved": "https://registry.npmjs.org/spdx-expression-parse/-/spdx-expression-parse-1.0.4.tgz",
+      "integrity": "sha1-m98vIOH0DtRH++JzJmGR/O1RYmw=",
+      "dev": true
+    },
+    "spdx-license-ids": {
+      "version": "1.2.2",
+      "resolved": "https://registry.npmjs.org/spdx-license-ids/-/spdx-license-ids-1.2.2.tgz",
+      "integrity": "sha1-yd96NCRZSt5r0RkA1ZZpbcBrrFc=",
+      "dev": true
+    },
+    "strip-ansi": {
+      "version": "4.0.0",
+      "resolved": "https://registry.npmjs.org/strip-ansi/-/strip-ansi-4.0.0.tgz",
+      "integrity": "sha1-qEeQIusaw2iocTibY1JixQXuNo8=",
+      "dev": true,
+      "requires": {
+        "ansi-regex": "^3.0.0"
+      }
+    },
+    "strip-ansi-cli": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/strip-ansi-cli/-/strip-ansi-cli-2.0.0.tgz",
+      "integrity": "sha1-D91Cq86DJTm/cv+ROSpxqzVGIIw=",
+      "dev": true,
+      "requires": {
+        "meow": "^3.7.0",
+        "strip-ansi": "^4.0.0"
+      }
+    },
+    "strip-bom": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/strip-bom/-/strip-bom-2.0.0.tgz",
+      "integrity": "sha1-YhmoVhZSBJHzV4i9vxRHqZx+aw4=",
+      "dev": true,
+      "requires": {
+        "is-utf8": "^0.2.0"
+      }
+    },
+    "strip-indent": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/strip-indent/-/strip-indent-1.0.1.tgz",
+      "integrity": "sha1-DHlipq3vp7vUrDZkYKY4VSrhoKI=",
+      "dev": true,
+      "requires": {
+        "get-stdin": "^4.0.1"
+      }
+    },
+    "trim-newlines": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/trim-newlines/-/trim-newlines-1.0.0.tgz",
+      "integrity": "sha1-WIeWa7WCpFA6QetST301ARgVphM=",
+      "dev": true
+    },
+    "validate-npm-package-license": {
+      "version": "3.0.1",
+      "resolved": "https://registry.npmjs.org/validate-npm-package-license/-/validate-npm-package-license-3.0.1.tgz",
+      "integrity": "sha1-KAS6vnEq0zeUWaz74kdGqywwP7w=",
+      "dev": true,
+      "requires": {
+        "spdx-correct": "~1.0.0",
+        "spdx-expression-parse": "~1.0.0"
+      }
+    }
+  }
+}

package.json

@@ -0,0 +1,26 @@
+{
+  "name": "oxipng",
+  "version": "1.0.0",
+  "description": "[![Build Status](https://travis-ci.org/shssoichiro/oxipng.svg?branch=master)](https://travis-ci.org/shssoichiro/oxipng) [![Version](https://img.shields.io/crates/v/oxipng.svg)](https://crates.io/crates/oxipng) [![License](https://img.shields.io/crates/l/oxipng.svg)](https://github.com/shssoichiro/oxipng/blob/master/LICENSE)",
+  "main": "index.js",
+  "private": true,
+  "directories": {
+    "test": "tests"
+  },
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/shssoichiro/oxipng.git"
+  },
+  "author": "",
+  "license": "ISC",
+  "bugs": {
+    "url": "https://github.com/shssoichiro/oxipng/issues"
+  },
+  "homepage": "https://github.com/shssoichiro/oxipng#readme",
+  "devDependencies": {
+    "strip-ansi-cli": "^2.0.0"
+  }
+}

rustfmt.toml

@@ -0,0 +1 @@
+format_strings = false

scripts/compare.sh

@@ -1,19 +1,14 @@
 #!/bin/bash
 cargo build --release
-sed -i.bak '/## Benchmarks/,$d' README.md
+cp README.template.md README.md
-rm README.md.bak
 
 CORES=$(sysctl -n hw.ncpu 2>/dev/null || grep -c ^processor /proc/cpuinfo)
 CPU=$(sysctl -n machdep.cpu.brand_string 2>/dev/null || grep '^model name' /proc/cpuinfo | sed 's/model name.\+: //g' | head -n 1)
 OXIPNG_VERSION=$(./target/release/oxipng -V)
 OPTIPNG_VERSION=$(optipng -v | head -n 1)
 RUST_VERSION=$(rustc -V)
-echo -e '## Benchmarks\n' >> README.md
 echo "Tested $OXIPNG_VERSION (compiled on $RUST_VERSION) against $OPTIPNG_VERSION on $CPU with $CORES logical cores" >> README.md
-echo -e '\n```\n' >> README.md
-
-hyperfine --style basic --warmup 5 './target/release/oxipng -P ./tests/files/rgb_16_should_be_grayscale_8.png' 'optipng -simulate ./tests/files/rgb_16_should_be_grayscale_8.png' >> README.md
 echo -e '\n\n' >> README.md
-hyperfine --style basic --warmup 5 './target/release/oxipng -o4 -P ./tests/files/rgb_16_should_be_grayscale_8.png' 'optipng -o 4 -simulate ./tests/files/rgb_16_should_be_grayscale_8.png' >> README.md
 
-echo -e '\n```' >> README.md
+hyperfine --warmup 5 './target/release/oxipng -P ./tests/files/rgb_16_should_be_grayscale_8.png' 'optipng -simulate ./tests/files/rgb_16_should_be_grayscale_8.png' | ./node_modules/.bin/strip-ansi >> README.md
+hyperfine --warmup 5 './target/release/oxipng -o4 -P ./tests/files/rgb_16_should_be_grayscale_8.png' 'optipng -o 4 -simulate ./tests/files/rgb_16_should_be_grayscale_8.png' | ./node_modules/.bin/strip-ansi >> README.md

scripts/manual.sh

@@ -1,7 +0,0 @@
-#!/bin/sh -eu
-cargo build
-cargo xtask mangen
-
-./target/debug/oxipng -V > MANUAL.txt
-#Redirect all streams to prevent detection of the terminal width and force an internal default of 100
-./target/debug/oxipng --help >> MANUAL.txt 2>/dev/null </dev/null

src/apng.rs

@@ -1,72 +0,0 @@
-use crate::{
-    PngResult,
-    error::PngError,
-    headers::{read_be_u16, read_be_u32},
-};
-
-#[derive(Debug, Clone)]
-/// Animated PNG frame
-pub struct Frame {
-    /// Width of the frame
-    pub width: u32,
-    /// Height of the frame
-    pub height: u32,
-    /// X offset of the frame
-    pub x_offset: u32,
-    /// Y offset of the frame
-    pub y_offset: u32,
-    /// Frame delay numerator
-    pub delay_num: u16,
-    /// Frame delay denominator
-    pub delay_den: u16,
-    /// Frame disposal operation
-    pub dispose_op: u8,
-    /// Frame blend operation
-    pub blend_op: u8,
-    /// Frame data, from fdAT chunks
-    pub data: Vec<u8>,
-}
-
-impl Frame {
-    /// Construct a new Frame from the data in a fcTL chunk
-    pub fn from_fctl_data(byte_data: &[u8]) -> PngResult<Self> {
-        if byte_data.len() < 26 {
-            return Err(PngError::TruncatedData);
-        }
-        Ok(Self {
-            width: read_be_u32(&byte_data[4..8]),
-            height: read_be_u32(&byte_data[8..12]),
-            x_offset: read_be_u32(&byte_data[12..16]),
-            y_offset: read_be_u32(&byte_data[16..20]),
-            delay_num: read_be_u16(&byte_data[20..22]),
-            delay_den: read_be_u16(&byte_data[22..24]),
-            dispose_op: byte_data[24],
-            blend_op: byte_data[25],
-            data: vec![],
-        })
-    }
-
-    /// Construct the data for a fcTL chunk using the given sequence number
-    #[must_use]
-    pub fn fctl_data(&self, sequence_number: u32) -> Vec<u8> {
-        let mut byte_data = Vec::with_capacity(26);
-        byte_data.extend_from_slice(&sequence_number.to_be_bytes());
-        byte_data.extend_from_slice(&self.width.to_be_bytes());
-        byte_data.extend_from_slice(&self.height.to_be_bytes());
-        byte_data.extend_from_slice(&self.x_offset.to_be_bytes());
-        byte_data.extend_from_slice(&self.y_offset.to_be_bytes());
-        byte_data.extend_from_slice(&self.delay_num.to_be_bytes());
-        byte_data.extend_from_slice(&self.delay_den.to_be_bytes());
-        byte_data.extend_from_slice(&[self.dispose_op, self.blend_op]);
-        byte_data
-    }
-
-    /// Construct the data for a fdAT chunk using the given sequence number
-    #[must_use]
-    pub fn fdat_data(&self, sequence_number: u32) -> Vec<u8> {
-        let mut byte_data = Vec::with_capacity(4 + self.data.len());
-        byte_data.extend_from_slice(&sequence_number.to_be_bytes());
-        byte_data.extend_from_slice(&self.data);
-        byte_data
-    }
-}

src/atomicmin.rs

@@ -1,25 +1,39 @@
-use std::sync::atomic::{AtomicUsize, Ordering::SeqCst};
+use std::sync::atomic::AtomicUsize;
+use std::sync::atomic::Ordering::{Relaxed, SeqCst};
 
-#[derive(Debug)]
 pub struct AtomicMin {
     val: AtomicUsize,
 }
 
 impl AtomicMin {
-    #[must_use]
     pub fn new(init: Option<usize>) -> Self {
         Self {
-            val: AtomicUsize::new(init.unwrap_or(usize::MAX)),
+            val: AtomicUsize::new(init.unwrap_or(usize::max_value())),
         }
     }
 
     pub fn get(&self) -> Option<usize> {
         let val = self.val.load(SeqCst);
-        if val == usize::MAX { None } else { Some(val) }
+        if val == usize::max_value() {
+            None
+        } else {
+            Some(val)
+        }
     }
 
-    /// Try a new value, returning true if it is the new minimum
+    pub fn set_min(&self, new_val: usize) {
-    pub fn set_min(&self, new_val: usize) -> bool {
+        let mut current_val = self.val.load(Relaxed);
-        new_val < self.val.fetch_min(new_val, SeqCst)
+        loop {
+            if new_val < current_val {
+                if let Err(v) = self
+                    .val
+                    .compare_exchange(current_val, new_val, SeqCst, Relaxed)
+                {
+                    current_val = v;
+                    continue;
+                }
+            }
+            break;
+        }
     }
 }

src/cli.rs

@@ -1,450 +0,0 @@
-use std::{num::NonZeroU64, path::PathBuf};
-
-use clap::builder::Styles;
-use clap::builder::styling::{AnsiColor, Effects};
-use clap::{Arg, ArgAction, Command, builder::ArgPredicate, value_parser};
-use parse_size::parse_size;
-
-include!("display_chunks.rs");
-
-const STYLES: Styles = Styles::styled()
-    .header(AnsiColor::Green.on_default().effects(Effects::BOLD))
-    .usage(AnsiColor::Green.on_default().effects(Effects::BOLD))
-    .literal(AnsiColor::Cyan.on_default().effects(Effects::BOLD))
-    .placeholder(AnsiColor::Cyan.on_default());
-
-pub fn build_command() -> Command {
-    // Note: clap 'wrap_help' is enabled to automatically wrap lines according to terminal width.
-    // To keep things tidy though, short help descriptions should be no more than 54 characters,
-    // so that they can fit on a single line in an 80 character terminal.
-    // Long help descriptions are soft wrapped here at 90 characters (column 91) but this does not
-    // affect output, it simply matches what is rendered when help is output to a file.
-    Command::new("oxipng")
-        .version(env!("CARGO_PKG_VERSION"))
-        .author("Joshua Holmer <jholmer.in@gmail.com>")
-        .about("Losslessly improve compression of PNG files")
-        .styles(STYLES)
-        .arg(
-            Arg::new("files")
-                .help("File(s) to compress (use '-' for stdin)")
-                .index(1)
-                .num_args(1..)
-                .use_value_delimiter(false)
-                .required(true)
-                .value_parser(value_parser!(PathBuf)),
-        )
-        .arg(
-            Arg::new("optimization")
-                .help("Optimization level (0-6, or max)")
-                .long_help("\
-Set the optimization level preset. The default level 2 is quite fast and provides good \
-compression. Lower levels are faster, higher levels provide better compression, though \
-with increasingly diminishing returns.
-
-    0   => --zc 5  --fast              (filter chosen heuristically)
-    1   => --zc 10 --fast              (filter chosen heuristically)
-    2   => --zc 11 -f 0,1,6,7 --fast
-    3   => --zc 11 -f 0,7,8,9         --brute-level 1 --brute-lines 3
-    4   => --zc 12 -f 0,7,8,9         --brute-level 1 --brute-lines 4
-    5   => --zc 12 -f 0,1,2,5,6,7,8,9 --brute-level 4 --brute-lines 4
-    6   => --zc 12 -f 0-9             --brute-level 5 --brute-lines 8
-    max => (stable alias for the maximum level)
-
-Manually specifying a compression option (zc, f, etc.) will override the optimization \
-preset, regardless of the order you write the arguments.")
-                .short('o')
-                .long("opt")
-                .value_name("level")
-                .default_value("2")
-                .value_parser(["0", "1", "2", "3", "4", "5", "6", "max"])
-                .hide_possible_values(true),
-        )
-        .arg(
-            Arg::new("recursive")
-                .help("Recurse input directories, optimizing all PNG files")
-                .long_help("\
-When directories are given as input, traverse the directory trees and optimize all PNG \
-files found (files with “.png” or “.apng” extension).")
-                .short('r')
-                .long("recursive")
-                .action(ArgAction::SetTrue),
-        )
-        .arg(
-            Arg::new("output_dir")
-                .help("Write output file(s) to <directory>")
-                .long_help("\
-Write output file(s) to <directory>. If the directory does not exist, it will be created. \
-Note that this will not preserve the directory structure of the input files when used with \
-'--recursive'.")
-                .long("dir")
-                .value_name("directory")
-                .value_parser(value_parser!(PathBuf))
-                .conflicts_with("output_file")
-                .conflicts_with("stdout"),
-        )
-        .arg(
-            Arg::new("output_file")
-                .help("Write output file to <file>")
-                .long("out")
-                .value_name("file")
-                .value_parser(value_parser!(PathBuf))
-                .conflicts_with("output_dir")
-                .conflicts_with("stdout"),
-        )
-        .arg(
-            Arg::new("stdout")
-                .help("Write output to stdout")
-                .long("stdout")
-                .action(ArgAction::SetTrue)
-                .conflicts_with("output_dir")
-                .conflicts_with("output_file"),
-        )
-        .arg(
-            Arg::new("preserve")
-                .help("Preserve file permissions and timestamps if possible")
-                .short('p')
-                .long("preserve")
-                .action(ArgAction::SetTrue),
-        )
-        .arg(
-            Arg::new("dry-run")
-                .help("Do not write any files, only show compression results")
-                .short('d')
-                .long("dry-run")
-                .action(ArgAction::SetTrue),
-        )
-        .arg(
-            Arg::new("strip-safe")
-                .help("Strip safely-removable chunks, same as '--strip safe'")
-                .short('s')
-                .action(ArgAction::SetTrue)
-                .conflicts_with("strip"),
-        )
-        .arg(
-            Arg::new("strip")
-                .help("Strip metadata (safe, all, or comma-separated list)\nCAUTION: 'all' will convert APNGs to standard PNGs")
-                .long_help(format!("\
-Strip metadata chunks, where <mode> is one of:
-
-    safe    =>  Strip all non-critical chunks, except for the following:
-                    {}
-    all     =>  Strip all non-critical chunks
-    <list>  =>  Strip chunks in the comma-separated list, e.g. 'bKGD,cHRM'
-
-CAUTION: 'all' will convert APNGs to standard PNGs.
-
-Please note that regardless of any options set, some chunks will necessarily be stripped \
-when invalidated by the optimization:
-    bKGD, sBIT, hIST: Stripped if the color type or bit depth changes.
-    iDOT: Always stripped.
-    caBX: Stripped if it contains C2PA metadata. If explicitly retained by `--keep`, \
-    optimization will be aborted.
-
-The default when --strip is not passed is to keep all chunks that remain valid.",
-                       DISPLAY_CHUNKS
-                           .iter()
-                           .map(|c| String::from_utf8_lossy(c))
-                           .collect::<Vec<_>>()
-                           .join(", ")))
-                .long("strip")
-                .value_name("mode")
-                .conflicts_with("strip-safe"),
-        )
-        .arg(
-            Arg::new("keep")
-                .help("Strip all metadata except in the comma-separated list")
-                .long_help("\
-Strip all metadata chunks except those in the comma-separated list. The special value \
-'display' includes chunks that affect the image appearance, equivalent to '--strip safe'.
-
-E.g. '--keep eXIf,display' will strip chunks, keeping only eXIf and those that affect the \
-image appearance.")
-                .long("keep")
-                .value_name("list")
-                .conflicts_with("strip")
-                .conflicts_with("strip-safe"),
-        )
-        .arg(
-            Arg::new("alpha")
-                .help("Perform additional alpha channel optimization")
-                .long_help("\
-Perform additional optimization on images with an alpha channel, by altering the color \
-values of fully transparent pixels. This is generally recommended for better compression, \
-but take care as while this is “visually lossless”, it is technically a lossy \
-transformation and may be unsuitable for some applications.")
-                .short('a')
-                .long("alpha")
-                .action(ArgAction::SetTrue),
-        )
-        .arg(
-            Arg::new("interlace")
-                .help("Set PNG interlacing (off, on, keep)")
-                .long_help("\
-Set the PNG interlacing mode, where <mode> is one of:
-
-    off   =>  Remove interlacing from all images that are processed
-    on    =>  Apply Adam7 interlacing on all images that are processed
-    keep  =>  Keep the existing interlacing mode of each image
-
-Note that interlacing can add 25-50% to the size of an optimized image. Only use it if you \
-believe the benefits outweigh the costs for your use case.")
-                .short('i')
-                .long("interlace")
-                .value_name("mode")
-                .value_parser(["off", "on", "keep", "0", "1"])
-                .default_value("off")
-                .default_value_if("no-reductions", ArgPredicate::IsPresent, "keep")
-                .hide_possible_values(true),
-        )
-        .arg(
-            Arg::new("scale16")
-                .help("Forcibly reduce 16-bit images to 8-bit (lossy)")
-                .long_help("\
-Forcibly reduce images with 16 bits per channel to 8 bits per channel. This is a lossy \
-operation but can provide significant savings when you have no need for higher depth. \
-Reduction is performed by scaling the values such that, e.g. 0x00FF is reduced to 0x01 \
-rather than 0x00.
-
-Without this flag, 16-bit images will only be reduced in depth if it can be done \
-losslessly.")
-                .long("scale16")
-                .action(ArgAction::SetTrue),
-        )
-        .arg(
-            Arg::new("verbose")
-                .help("Show per-file info (use multiple times for more detail)")
-                .short('v')
-                .long("verbose")
-                .action(ArgAction::Count)
-                .conflicts_with("quiet"),
-        )
-        .arg(
-            Arg::new("quiet")
-                .help("Suppress all output messages")
-                .short('q')
-                .long("quiet")
-                .action(ArgAction::SetTrue)
-                .conflicts_with("verbose"),
-        )
-        .arg(
-            Arg::new("json")
-                .help("Print results as JSON")
-                .short('j')
-                .long("json")
-                .action(ArgAction::SetTrue)
-                .conflicts_with("stdout"),
-        )
-        .arg(
-            Arg::new("filters")
-                .help("Filters to try (0-9; see '--help' for details)")
-                .long_help("\
-Perform compression trials with each of the given filter types. You can specify a \
-comma-separated list, or a range of values. E.g. '-f 0-3' is the same as '-f 0,1,2,3'.
-
-PNG delta filters (apply the same filter to every line)
-    0  =>  None      (recommended to always include this filter)
-    1  =>  Sub
-    2  =>  Up
-    3  =>  Average
-    4  =>  Paeth
-
-Heuristic strategies (try to find the best delta filter for each line)
-    5  =>  MinSum    Minimum sum of absolute differences
-    6  =>  Entropy   Smallest Shannon entropy
-    7  =>  Bigrams   Lowest count of distinct bigrams
-    8  =>  BigEnt    Smallest Shannon entropy of bigrams
-    9  =>  Brute     Smallest compressed size (slow)
-
-The default value depends on the optimization level preset.")
-                .short('f')
-                .long("filters")
-                .value_name("list"),
-        )
-        .arg(
-            Arg::new("fast")
-                .help("Use fast filter evaluation")
-                .long_help("\
-Perform a fast compression evaluation of each enabled filter, followed by a single main \
-compression trial of the best result. Recommended if you have more filters enabled than \
-CPU cores.")
-                .long("fast")
-                .action(ArgAction::SetTrue),
-        )
-        .arg(
-            Arg::new("compression")
-                .help("Deflate compression level (0-12)")
-                .long_help("\
-Deflate compression level (0-12) for main compression trials. The levels here are defined \
-by the libdeflate compression library.
-
-The default value depends on the optimization level preset.")
-                .long("zc")
-                .value_name("level")
-                .value_parser(0..=12)
-                .conflicts_with("zopfli"),
-        )
-        .arg(
-            Arg::new("no-bit-reduction")
-                .help("Do not change bit depth")
-                .long("nb")
-                .action(ArgAction::SetTrue),
-        )
-        .arg(
-            Arg::new("no-color-reduction")
-                .help("Do not change color type")
-                .long("nc")
-                .action(ArgAction::SetTrue),
-        )
-        .arg(
-            Arg::new("no-palette-reduction")
-                .help("Do not change color palette")
-                .long_help("\
-Do not convert to indexed and do not modify an existing color palette.")
-                .long("np")
-                .action(ArgAction::SetTrue),
-        )
-        .arg(
-            Arg::new("no-grayscale-reduction")
-                .help("Do not change to or from grayscale")
-                .long("ng")
-                .action(ArgAction::SetTrue),
-        )
-        .arg(
-            Arg::new("no-reductions")
-                .help("Do not perform any transformations")
-                .long_help("\
-Do not perform any transformations and do not deinterlace by default.")
-                .long("nx")
-                .action(ArgAction::SetTrue),
-        )
-        .arg(
-            Arg::new("no-recoding")
-                .help("Do not recompress unless transformations occur")
-                .long_help("\
-Do not recompress IDAT unless required due to transformations. Recompression of other \
-compressed chunks (such as iCCP) will also be disabled. Note that the combination of \
-'--nx' and '--nz' will fully disable all optimization.")
-                .long("nz")
-                .action(ArgAction::SetTrue),
-        )
-        .arg(
-            Arg::new("fix")
-                .help("Disable checksum validation")
-                .long_help("\
-Do not perform checksum validation of PNG chunks. This may allow some files with errors to \
-be processed successfully. The output will always have correct checksums.")
-                .long("fix")
-                .action(ArgAction::SetTrue),
-        )
-        .arg(
-            Arg::new("force")
-                .help("Write the output even if it is larger than the input")
-                .long("force")
-                .action(ArgAction::SetTrue),
-        )
-        .arg(
-            Arg::new("zopfli")
-                .help("Use the much slower but stronger Zopfli compressor")
-                .long_help("\
-Use the much slower but stronger Zopfli compressor for main compression trials. \
-Recommended use is with '-o max' and '--fast'.")
-                .short('z')
-                .short_alias('Z') // Kept for backwards compatibility
-                .long("zopfli")
-                .action(ArgAction::SetTrue),
-        )
-        .arg(
-            Arg::new("iterations")
-                .help("Number of Zopfli iterations")
-                .long_help("\
-Set the number of iterations to use for Zopfli compression. Using fewer iterations may \
-speed up compression for large files. This option requires '--zopfli' to be set.")
-                .long("zi")
-                .value_name("iterations")
-                .default_value("15")
-                .value_parser(value_parser!(NonZeroU64))
-                .requires("zopfli"),
-        )
-        .arg(
-            Arg::new("iterations-without-improvement")
-                .hide_short_help(true)
-                .long_help("\
-Stop Zopfli compression after this number of iterations without improvement. Use this in \
-conjunction with a high value for '--zi' to achieve better compression in reasonable time.")
-                .long("ziwi")
-                .value_name("iterations")
-                .value_parser(value_parser!(NonZeroU64))
-                .requires("zopfli"),
-        )
-        .arg(
-            Arg::new("brute-level")
-                .hide_short_help(true)
-                .long_help("\
-Set the libdeflate compression level to use with the Brute filter strategy. Sane values \
-are 1-5. Higher values are not necessarily better.")
-                .long("brute-level")
-                .value_name("level")
-                .value_parser(1..=12),
-        )
-        .arg(
-            Arg::new("brute-lines")
-                .hide_short_help(true)
-                .long_help("\
-Set the number of lines to compress at once with the Brute filter strategy. Sane values \
-are 2-16. Higher values are not necessarily better.")
-                .long("brute-lines")
-                .value_name("lines")
-                .value_parser(value_parser!(usize)),
-        )
-        .arg(
-            Arg::new("timeout")
-                .help("Maximum amount of time to spend on optimizations")
-                .long_help("\
-Maximum amount of time, in seconds, to spend on optimizations. Oxipng will check the \
-timeout before each transformation or compression trial, and will stop trying to optimize \
-the file if the timeout is exceeded. Note that this does not cut short any operations that \
-are already in progress, so it is currently of limited effectiveness for large files with \
-high compression levels.")
-                .long("timeout")
-                .value_name("secs")
-                .value_parser(value_parser!(u64)),
-        )
-        .arg(
-            Arg::new("max-size")
-                .help("Skip image if the decompressed size exceeds this limit")
-                .long_help("\
-Maximum size to allow for the input image. If the raw, decompressed image data (or the \
-file size) of the image exceeds this size, it will be skipped. This is useful for limiting \
-memory usage or avoiding long processing times on large images. The value may be specified \
-with a unit suffix such as k, KB, m, MB, etc.
-
-The decompressed size of an image is roughly equal to width * height * bit-depth / 8. E.g. \
-a 1920x1080 image with 24-bit color depth would be roughly 6MB.")
-                .long("max-raw-size")
-                .value_name("bytes")
-                .value_parser(|s: &str| parse_size(s)),
-        )
-        .arg(
-            Arg::new("threads")
-                .help("Number of threads to use [default: num logical CPUs]")
-                .long_help("\
-Set the maximum number of threads to use. Oxipng uses multithreading to evaluate multiple \
-optimizations on the same file in parallel as well as process multiple files in parallel. \
-You can set this to a lower value if you need to limit memory or CPU usage.
-
-[default: num logical CPUs]")
-                .short('t')
-                .long("threads")
-                .value_name("num")
-                .value_parser(value_parser!(usize)),
-        )
-        .arg(
-            Arg::new("parallel-files")
-                .help("Process multiple files sequentially")
-                .long_help("\
-Process multiple files sequentially rather than in parallel. Use this if you need \
-determinism in the processing order. Note this is not necessary if using '--threads 1'.")
-                .long("sequential")
-                .action(ArgAction::SetFalse),
-        )
-}

src/colors.rs

@@ -1,129 +1,145 @@
-use std::{fmt, fmt::Display};
+use std::fmt;
 
-use rgb::{RGB16, RGBA8};
+#[derive(Debug, PartialEq, Clone, Copy)]
-
-use crate::PngError;
-
-#[derive(Debug, PartialEq, Eq, Clone)]
 /// The color type used to represent this image
 pub enum ColorType {
     /// Grayscale, with one color channel
-    Grayscale {
+    Grayscale,
-        /// Optional shade of gray that should be rendered as transparent
-        transparent_shade: Option<u16>,
-    },
     /// RGB, with three color channels
-    RGB {
+    RGB,
-        /// Optional color value that should be rendered as transparent
+    /// Indexed, with one byte per pixel representing one of up to 256 colors in the image
-        transparent_color: Option<RGB16>,
+    Indexed,
-    },
-    /// Indexed, with one byte per pixel representing a color from the palette
-    Indexed {
-        /// The palette containing the colors used, up to 256 entries
-        palette: Vec<RGBA8>,
-    },
     /// Grayscale + Alpha, with two color channels
     GrayscaleAlpha,
     /// RGBA, with four color channels
     RGBA,
 }
 
-impl Display for ColorType {
+impl fmt::Display for ColorType {
     #[inline]
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        match self {
+        write!(
-            Self::Grayscale { .. } => write!(f, "Grayscale"),
+            f,
-            Self::RGB { .. } => write!(f, "RGB"),
+            "{}",
-            Self::Indexed { palette } => write!(f, "Indexed ({} colors)", palette.len()),
+            match *self {
-            Self::GrayscaleAlpha => write!(f, "Grayscale + Alpha"),
+                ColorType::Grayscale => "Grayscale",
-            Self::RGBA => write!(f, "RGB + Alpha"),
+                ColorType::RGB => "RGB",
-        }
+                ColorType::Indexed => "Indexed",
+                ColorType::GrayscaleAlpha => "Grayscale + Alpha",
+                ColorType::RGBA => "RGB + Alpha",
+            }
+        )
     }
 }
 
 impl ColorType {
     /// Get the code used by the PNG specification to denote this color type
     #[inline]
-    #[must_use]
+    pub fn png_header_code(self) -> u8 {
-    pub const fn png_header_code(&self) -> u8 {
         match self {
-            Self::Grayscale { .. } => 0,
+            ColorType::Grayscale => 0,
-            Self::RGB { .. } => 2,
+            ColorType::RGB => 2,
-            Self::Indexed { .. } => 3,
+            ColorType::Indexed => 3,
-            Self::GrayscaleAlpha => 4,
+            ColorType::GrayscaleAlpha => 4,
-            Self::RGBA => 6,
+            ColorType::RGBA => 6,
         }
     }
 
     #[inline]
-    pub(crate) const fn channels_per_pixel(&self) -> u8 {
+    pub fn channels_per_pixel(self) -> u8 {
         match self {
-            Self::Grayscale { .. } | Self::Indexed { .. } => 1,
+            ColorType::Grayscale | ColorType::Indexed => 1,
-            Self::GrayscaleAlpha => 2,
+            ColorType::GrayscaleAlpha => 2,
-            Self::RGB { .. } => 3,
+            ColorType::RGB => 3,
-            Self::RGBA => 4,
+            ColorType::RGBA => 4,
-        }
-    }
-
-    #[inline]
-    pub(crate) const fn is_rgb(&self) -> bool {
-        matches!(self, Self::RGB { .. } | Self::RGBA)
-    }
-
-    #[inline]
-    pub(crate) const fn is_gray(&self) -> bool {
-        matches!(self, Self::Grayscale { .. } | Self::GrayscaleAlpha)
-    }
-
-    #[inline]
-    pub(crate) const fn has_alpha(&self) -> bool {
-        matches!(self, Self::GrayscaleAlpha | Self::RGBA)
-    }
-
-    #[inline]
-    pub(crate) const fn has_trns(&self) -> bool {
-        match self {
-            Self::Grayscale { transparent_shade } => transparent_shade.is_some(),
-            Self::RGB { transparent_color } => transparent_color.is_some(),
-            _ => false,
         }
     }
 }
 
-#[repr(u8)]
+#[derive(Debug, PartialEq, Clone, Copy)]
-#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone, Copy)]
 /// The number of bits to be used per channel per pixel
 pub enum BitDepth {
     /// One bit per channel per pixel
-    One = 1,
+    One,
     /// Two bits per channel per pixel
-    Two = 2,
+    Two,
     /// Four bits per channel per pixel
-    Four = 4,
+    Four,
     /// Eight bits per channel per pixel
-    Eight = 8,
+    Eight,
     /// Sixteen bits per channel per pixel
-    Sixteen = 16,
+    Sixteen,
 }
 
-impl TryFrom<u8> for BitDepth {
+impl fmt::Display for BitDepth {
-    type Error = PngError;
+    #[inline]
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(
+            f,
+            "{}",
+            match *self {
+                BitDepth::One => "1",
+                BitDepth::Two => "2",
+                BitDepth::Four => "4",
+                BitDepth::Eight => "8",
+                BitDepth::Sixteen => "16",
+            }
+        )
+    }
+}
 
-    fn try_from(value: u8) -> Result<Self, Self::Error> {
+impl BitDepth {
-        match value {
+    /// Retrieve the number of bits per channel per pixel as a `u8`
-            1 => Ok(Self::One),
+    #[inline]
-            2 => Ok(Self::Two),
+    pub fn as_u8(self) -> u8 {
-            4 => Ok(Self::Four),
+        match self {
-            8 => Ok(Self::Eight),
+            BitDepth::One => 1,
-            16 => Ok(Self::Sixteen),
+            BitDepth::Two => 2,
-            _ => Err(PngError::InvalidData),
+            BitDepth::Four => 4,
+            BitDepth::Eight => 8,
+            BitDepth::Sixteen => 16,
+        }
+    }
+    /// Parse a number of bits per channel per pixel into a `BitDepth`
+    #[inline]
+    pub fn from_u8(depth: u8) -> BitDepth {
+        match depth {
+            1 => BitDepth::One,
+            2 => BitDepth::Two,
+            4 => BitDepth::Four,
+            8 => BitDepth::Eight,
+            16 => BitDepth::Sixteen,
+            _ => panic!("Unsupported bit depth"),
         }
     }
 }
 
-impl Display for BitDepth {
+#[derive(Debug, PartialEq, Clone, Copy, Eq, Hash)]
-    #[inline]
+/// Potential optimization methods for alpha channel
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+pub enum AlphaOptim {
-        Display::fmt(&(*self as u8).to_string(), f)
+    NoOp,
+    Black,
+    White,
+    Up,
+    Right,
+    Down,
+    Left,
+}
+
+impl fmt::Display for AlphaOptim {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(
+            f,
+            "{}",
+            match *self {
+                AlphaOptim::NoOp => "_",
+                AlphaOptim::Black => "B",
+                AlphaOptim::White => "W",
+                AlphaOptim::Up => "U",
+                AlphaOptim::Right => "R",
+                AlphaOptim::Down => "D",
+                AlphaOptim::Left => "L",
+            }
+        )
     }
 }

src/deflate/deflater.rs

@@ -1,36 +0,0 @@
-use libdeflater::*;
-
-use crate::{PngError, PngResult};
-
-pub fn deflate(data: &[u8], level: u8, max_size: Option<usize>) -> PngResult<Vec<u8>> {
-    let mut compressor = Compressor::new(CompressionLvl::new(level.into()).unwrap());
-    let capacity = max_size.unwrap_or_else(|| compressor.zlib_compress_bound(data.len()));
-    let mut dest = vec![0; capacity];
-    let len = compressor
-        .zlib_compress(data, &mut dest)
-        .map_err(|err| match err {
-            CompressionError::InsufficientSpace => PngError::DeflatedDataTooLong(capacity),
-        })?;
-    dest.truncate(len);
-    Ok(dest)
-}
-
-pub fn inflate(data: &[u8], out_size: usize) -> PngResult<Vec<u8>> {
-    let mut decompressor = Decompressor::new();
-    let mut dest = vec![0; out_size];
-    let len = decompressor
-        .zlib_decompress(data, &mut dest)
-        .map_err(|err| match err {
-            DecompressionError::BadData => PngError::InvalidData,
-            DecompressionError::InsufficientSpace => PngError::InflatedDataTooLong(out_size),
-        })?;
-    dest.truncate(len);
-    Ok(dest)
-}
-
-#[must_use]
-pub fn crc32(data: &[u8]) -> u32 {
-    let mut crc = Crc::new();
-    crc.update(data);
-    crc.sum()
-}

src/deflate/miniz_stream.rs

@@ -0,0 +1,67 @@
+use atomicmin::AtomicMin;
+use error::PngError;
+use miniz_oxide::deflate::core::*;
+use PngResult;
+
+pub fn compress_to_vec_oxipng(
+    input: &[u8],
+    level: u8,
+    window_bits: i32,
+    strategy: i32,
+    max_size: &AtomicMin,
+) -> PngResult<Vec<u8>> {
+    // The comp flags function sets the zlib flag if the window_bits parameter is > 0.
+    let flags = create_comp_flags_from_zip_params(level.into(), window_bits, strategy);
+    let mut compressor = CompressorOxide::new(flags);
+    // if max size is known, then expect that much data (but no more than input.len())
+    let mut output = Vec::with_capacity(max_size.get().unwrap_or(input.len() / 2).min(input.len()));
+    // # Unsafe
+    // We trust compress to not read the uninitialized bytes.
+    unsafe {
+        let cap = output.capacity();
+        output.set_len(cap);
+    }
+    let mut in_pos = 0;
+    let mut out_pos = 0;
+    loop {
+        let (status, bytes_in, bytes_out) = compress(
+            &mut compressor,
+            &input[in_pos..],
+            &mut output[out_pos..],
+            TDEFLFlush::Finish,
+        );
+
+        out_pos += bytes_out;
+        in_pos += bytes_in;
+
+        match status {
+            TDEFLStatus::Done => {
+                output.truncate(out_pos);
+                break;
+            }
+            TDEFLStatus::Okay => {
+                if let Some(max) = max_size.get() {
+                    if output.len() > max {
+                        return Err(PngError::DeflatedDataTooLong(output.len()));
+                    }
+                }
+                // We need more space, so extend the vector.
+                if output.len().saturating_sub(out_pos) < 30 {
+                    let current_len = output.len();
+                    output.reserve(current_len);
+
+                    // # Unsafe
+                    // We trust compress to not read the uninitialized bytes.
+                    unsafe {
+                        let cap = output.capacity();
+                        output.set_len(cap);
+                    }
+                }
+            }
+            // Not supposed to happen unless there is a bug.
+            _ => panic!("Bug! Unexpectedly failed to compress!"),
+        }
+    }
+
+    Ok(output)
+}

src/deflate/mod.rs

@@ -1,53 +1,123 @@
-mod deflater;
+use atomicmin::AtomicMin;
-use std::{fmt, fmt::Display};
+use error::PngError;
+use miniz_oxide;
+use std::cmp::max;
+use zopfli;
+use PngResult;
 
-pub use deflater::{crc32, deflate, inflate};
+#[doc(hidden)]
+pub mod miniz_stream;
 
-use crate::{PngError, PngResult};
+/// Decompress a data stream using the DEFLATE algorithm
-
+pub fn inflate(data: &[u8]) -> PngResult<Vec<u8>> {
-#[cfg(feature = "zopfli")]
+    miniz_oxide::inflate::decompress_to_vec_zlib(data)
-mod zopfli_oxipng;
+        .map_err(|e| PngError::new(&format!("Error on decompress: {:?}", e)))
-#[cfg(feature = "zopfli")]
-pub use zopfli::Options as ZopfliOptions;
-#[cfg(feature = "zopfli")]
-pub use zopfli_oxipng::deflate as zopfli_deflate;
-
-/// DEFLATE algorithms supported by oxipng (for use in [`Options`][crate::Options])
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
-pub enum Deflater {
-    /// Use libdeflater.
-    Libdeflater {
-        /// Which compression level to use on the file (0-12)
-        compression: u8,
-    },
-    #[cfg(feature = "zopfli")]
-    /// Use the better but slower Zopfli implementation
-    Zopfli(ZopfliOptions),
 }
 
-impl Deflater {
+/// Compress a data stream using the DEFLATE algorithm
-    pub(crate) fn deflate(self, data: &[u8], max_size: Option<usize>) -> PngResult<Vec<u8>> {
+#[cfg(any(target_arch = "x86_64", target_arch = "aarch64"))]
-        let compressed = match self {
+pub fn deflate(data: &[u8], zc: u8, zs: u8, zw: u8, max_size: &AtomicMin) -> PngResult<Vec<u8>> {
-            Self::Libdeflater { compression } => deflate(data, compression, max_size)?,
+    if is_cfzlib_supported() {
-            #[cfg(feature = "zopfli")]
+        return cfzlib_deflate(data, zc, zs, zw, max_size);
-            Self::Zopfli(options) => zopfli_deflate(data, options)?,
+    }
-        };
+
-        if let Some(max) = max_size {
+    miniz_stream::compress_to_vec_oxipng(data, zc, zw.into(), zs.into(), max_size)
-            if compressed.len() > max {
+}
-                return Err(PngError::DeflatedDataTooLong(max));
+
+/// Compress a data stream using the DEFLATE algorithm
+#[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
+pub fn deflate(data: &[u8], zc: u8, zs: u8, zw: u8, max_size: &AtomicMin) -> PngResult<Vec<u8>> {
+    miniz_stream::compress_to_vec_oxipng(data, zc, zw.into(), zs.into(), max_size)
+}
+
+#[cfg(target_arch = "x86_64")]
+fn is_cfzlib_supported() -> bool {
+    if is_x86_feature_detected!("sse4.2") && is_x86_feature_detected!("pclmulqdq") {
+        return true;
+    }
+    false
+}
+
+#[cfg(target_arch = "aarch64")]
+fn is_cfzlib_supported() -> bool {
+    if is_arm_feature_detected!("neon") && is_arm_feature_detected!("crc") {
+        return true;
+    }
+    false
+}
+
+#[cfg(any(target_arch = "x86_64", target_arch = "aarch64"))]
+pub fn cfzlib_deflate(
+    data: &[u8],
+    level: u8,
+    strategy: u8,
+    window_bits: u8,
+    max_size: &AtomicMin,
+) -> PngResult<Vec<u8>> {
+    use cloudflare_zlib_sys::*;
+    use std::mem;
+
+    assert!(data.len() < u32::max_value() as usize);
+    unsafe {
+        let mut stream = mem::zeroed();
+        if Z_OK != deflateInit2(
+            &mut stream,
+            level.into(),
+            Z_DEFLATED,
+            window_bits.into(),
+            MAX_MEM_LEVEL,
+            strategy.into(),
+        ) {
+            return Err(PngError::new("deflateInit2"));
+        }
+
+        let upper_bound = deflateBound(&mut stream, data.len() as uLong) as usize;
+        let max_size = max_size.get().unwrap_or(upper_bound).min(upper_bound);
+        // it's important to have the capacity pre-allocated,
+        // as unsafe set_len is called later
+        let mut out = Vec::with_capacity(max_size);
+
+        stream.next_in = data.as_ptr() as *mut _;
+        stream.total_in = data.len() as uLong;
+        stream.avail_in = data.len() as uInt;
+        stream.next_out = out.as_mut_ptr();
+        stream.avail_out = out.capacity() as uInt;
+        match deflate(&mut stream, Z_FINISH) {
+            Z_STREAM_END => {}
+            Z_OK | Z_BUF_ERROR => {
+                deflateEnd(&mut stream);
+                return Err(PngError::DeflatedDataTooLong(stream.total_out as usize));
+            }
+            _ => {
+                deflateEnd(&mut stream);
+                return Err(PngError::new("deflate"));
             }
         }
-        Ok(compressed)
+        if Z_OK != deflateEnd(&mut stream) {
+            return Err(PngError::new("deflateEnd"));
+        }
+        debug_assert!(stream.total_out as usize <= out.capacity());
+        out.set_len(stream.total_out as usize);
+        Ok(out)
     }
 }
 
-impl Display for Deflater {
+pub fn zopfli_deflate(data: &[u8]) -> PngResult<Vec<u8>> {
-    #[inline]
+    let mut output = Vec::with_capacity(max(1024, data.len() / 20));
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+    let options = zopfli::Options::default();
-        match self {
+    match zopfli::compress(&options, &zopfli::Format::Zlib, data, &mut output) {
-            Self::Libdeflater { compression } => write!(f, "zc = {compression}"),
+        Ok(_) => (),
-            #[cfg(feature = "zopfli")]
+        Err(_) => return Err(PngError::new("Failed to compress in zopfli")),
-            Self::Zopfli(options) => write!(f, "zopfli, zi = {}", options.iteration_count),
+    };
-        }
+    output.shrink_to_fit();
-    }
+    Ok(output)
+}
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+/// DEFLATE algorithms supported by oxipng
+pub enum Deflaters {
+    /// Use the Zlib/Miniz DEFLATE implementation
+    Zlib,
+    /// Use the better but slower Zopfli implementation
+    Zopfli,
 }

src/deflate/zopfli_oxipng.rs

@@ -1,13 +0,0 @@
-use crate::{PngError, PngResult};
-
-pub fn deflate(data: &[u8], options: zopfli::Options) -> PngResult<Vec<u8>> {
-    let mut output = Vec::with_capacity(data.len());
-    // Since Rust v1.74, passing &[u8] directly into zopfli causes a regression in compressed size
-    // for some files. Wrapping the slice in another Read implementer such as Box fixes it for now.
-    match zopfli::compress(options, zopfli::Format::Zlib, Box::new(data), &mut output) {
-        Ok(()) => (),
-        Err(_) => return Err(PngError::new("Failed to compress in zopfli")),
-    }
-    output.shrink_to_fit();
-    Ok(output)
-}

src/display_chunks.rs

@@ -1,4 +0,0 @@
-/// List of chunks that affect image display and will be kept when using the `Safe` chunk strip option
-pub const DISPLAY_CHUNKS: [[u8; 4]; 7] = [
-    *b"cICP", *b"iCCP", *b"sRGB", *b"pHYs", *b"acTL", *b"fcTL", *b"fdAT",
-];

src/error.rs

@@ -1,69 +1,49 @@
-use std::{error::Error, fmt};
+use std::error::Error;
+use std::fmt;
 
-use crate::colors::{BitDepth, ColorType};
+// TODO: Use `#[non_exhaustive]` once stabilized
-
+// https://github.com/rust-lang/rust/issues/44109
-#[derive(Debug)]
+#[derive(Debug, Clone)]
-#[non_exhaustive]
 pub enum PngError {
-    APNGOutOfOrder,
-    C2PAMetadataPreventsChanges,
-    ChunkMissing(&'static str),
-    CRCMismatch([u8; 4]),
     DeflatedDataTooLong(usize),
-    IncorrectDataLength(usize, usize),
-    InflatedDataTooLong(usize),
-    InvalidData,
-    InvalidDepthForType(BitDepth, ColorType),
     NotPNG,
-    ReadFailed(String, std::io::Error),
+    APNGNotSupported,
+    InvalidData,
     TruncatedData,
-    WriteFailed(String, std::io::Error),
+    ChunkMissing(&'static str),
     Other(Box<str>),
+    #[doc(hidden)]
+    _Nonexhaustive,
 }
 
-impl Error for PngError {}
+impl Error for PngError {
+    // deprecated
+    fn description(&self) -> &str {
+        ""
+    }
+}
 
 impl fmt::Display for PngError {
     #[inline]
-    #[cold]
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
-            Self::APNGOutOfOrder => f.write_str("APNG chunks are out of order"),
+            PngError::DeflatedDataTooLong(_) => f.write_str("deflated data too long"),
-            Self::C2PAMetadataPreventsChanges => f.write_str(
+            PngError::NotPNG => f.write_str("Invalid header detected; Not a PNG file"),
-                "The image contains C2PA manifest that would be invalidated by any file changes",
+            PngError::InvalidData => f.write_str("Invalid data found; unable to read PNG file"),
-            ),
+            PngError::TruncatedData => {
-            Self::ChunkMissing(s) => write!(f, "Chunk {s} missing or empty"),
+                f.write_str("Missing data in the file; the file is truncated")
-            Self::CRCMismatch(ref c) => write!(
-                f,
-                "CRC mismatch in {} chunk; May be recoverable by using --fix",
-                String::from_utf8_lossy(c)
-            ),
-            Self::DeflatedDataTooLong(_) => f.write_str("Deflated data too long"),
-            Self::IncorrectDataLength(l1, l2) => write!(
-                f,
-                "Data length {l1} does not match the expected length {l2}"
-            ),
-            Self::InflatedDataTooLong(max) => write!(
-                f,
-                "Inflated data would exceed the maximum size ({max} bytes)"
-            ),
-            Self::InvalidData => f.write_str("Invalid data found; unable to read PNG file"),
-            Self::InvalidDepthForType(d, ref c) => {
-                write!(f, "Invalid bit depth {d} for color type {c}")
             }
-            Self::NotPNG => f.write_str("Invalid header detected; Not a PNG file"),
+            PngError::APNGNotSupported => f.write_str("APNG files are not (yet) supported"),
-            Self::ReadFailed(ref s, ref e) => write!(f, "Failed to read from {s}: {e}"),
+            PngError::ChunkMissing(s) => write!(f, "Chunk {} missing or empty", s),
-            Self::TruncatedData => f.write_str("Missing data in the file; the file is truncated"),
+            PngError::Other(ref s) => f.write_str(s),
-            Self::WriteFailed(ref s, ref e) => write!(f, "Failed to write to {s}: {e}"),
+            PngError::_Nonexhaustive => unreachable!(),
-            Self::Other(ref s) => f.write_str(s),
         }
     }
 }
 
 impl PngError {
-    #[cold]
+    #[inline]
-    #[must_use]
+    pub fn new(description: &str) -> PngError {
-    pub fn new(description: &str) -> Self {
+        PngError::Other(description.into())
-        Self::Other(description.into())
     }
 }

src/evaluate.rs

@@ -1,202 +0,0 @@
-//! Check if a reduction makes file smaller, and keep best reductions.
-//! Works asynchronously when possible
-
-#[cfg(not(feature = "parallel"))]
-use std::cell::RefCell;
-use std::sync::{
-    Arc,
-    atomic::{AtomicUsize, Ordering::*},
-};
-
-use deflate::Deflater;
-use indexmap::IndexSet;
-use log::trace;
-use rayon::prelude::*;
-#[cfg(feature = "parallel")]
-use std::sync::mpsc::{Receiver, Sender, channel};
-
-#[cfg(not(feature = "parallel"))]
-use crate::rayon;
-use crate::{
-    Deadline, PngError, atomicmin::AtomicMin, deflate, filters::FilterStrategy, png::PngImage,
-};
-
-pub(crate) struct Candidate {
-    pub image: Arc<PngImage>,
-    pub idat_data: Option<Vec<u8>>,
-    pub estimated_output_size: usize,
-    /// The input filter, which is retained for printing and for APNG frames.
-    pub filter: FilterStrategy,
-    /// The filter returned by the filter function, which may be Predefined.
-    /// Use this for the next round to avoid recomputing the filter.
-    pub filter_used: FilterStrategy,
-    /// For determining tie-breaker
-    nth: usize,
-}
-
-impl Candidate {
-    fn cmp_key(&self) -> impl Ord + use<> {
-        (
-            self.estimated_output_size,
-            self.image.data.len(),
-            self.filter.clone(),
-            // Prefer the later image added (e.g. baseline, which is always added last)
-            usize::MAX - self.nth,
-        )
-    }
-}
-
-/// Collect image versions and pick one that compresses best
-pub(crate) struct Evaluator {
-    deadline: Arc<Deadline>,
-    filters: IndexSet<FilterStrategy>,
-    deflater: Deflater,
-    optimize_alpha: bool,
-    final_round: bool,
-    nth: AtomicUsize,
-    executed: Arc<AtomicUsize>,
-    best_candidate_size: Arc<AtomicMin>,
-    /// images are sent to the caller thread for evaluation
-    #[cfg(feature = "parallel")]
-    eval_channel: (Sender<Candidate>, Receiver<Candidate>),
-    // in non-parallel mode, images are evaluated synchronously
-    #[cfg(not(feature = "parallel"))]
-    eval_best_candidate: RefCell<Option<Candidate>>,
-}
-
-impl Evaluator {
-    pub fn new(
-        deadline: Arc<Deadline>,
-        filters: IndexSet<FilterStrategy>,
-        deflater: Deflater,
-        optimize_alpha: bool,
-        final_round: bool,
-    ) -> Self {
-        #[cfg(feature = "parallel")]
-        let eval_channel = channel();
-        Self {
-            deadline,
-            filters,
-            deflater,
-            optimize_alpha,
-            final_round,
-            nth: AtomicUsize::new(0),
-            executed: Arc::new(AtomicUsize::new(0)),
-            best_candidate_size: Arc::new(AtomicMin::new(None)),
-            #[cfg(feature = "parallel")]
-            eval_channel,
-            #[cfg(not(feature = "parallel"))]
-            eval_best_candidate: RefCell::new(None),
-        }
-    }
-
-    /// Wait for all evaluations to finish and return smallest reduction
-    /// Or `None` if the queue is empty.
-    #[cfg(feature = "parallel")]
-    pub fn get_best_candidate(self) -> Option<Candidate> {
-        let (eval_send, eval_recv) = self.eval_channel;
-        // Disconnect the sender, breaking the loop in the thread
-        drop(eval_send);
-        let nth = self.nth.load(SeqCst);
-        // Yield to ensure all evaluations are executed
-        // This can prevent deadlocks when run within an existing rayon thread pool
-        while self.executed.load(Relaxed) < nth {
-            rayon::yield_local();
-        }
-        eval_recv.into_iter().min_by_key(Candidate::cmp_key)
-    }
-
-    #[cfg(not(feature = "parallel"))]
-    pub fn get_best_candidate(self) -> Option<Candidate> {
-        self.eval_best_candidate.into_inner()
-    }
-
-    /// Set best size, if known in advance
-    pub fn set_best_size(&self, size: usize) {
-        self.best_candidate_size.set_min(size);
-    }
-
-    /// Check if the image is smaller than others
-    pub fn try_image(&self, image: Arc<PngImage>) {
-        let description = image.ihdr.color_type.to_string();
-        self.try_image_with_description(image, &description);
-    }
-
-    /// Check if the image is smaller than others, with a description for verbose mode
-    pub fn try_image_with_description(&self, image: Arc<PngImage>, description: &str) {
-        let nth = self.nth.fetch_add(1, SeqCst);
-        // These clones are only cheap refcounts
-        let deadline = self.deadline.clone();
-        let filters = self.filters.clone();
-        let deflater = self.deflater;
-        let optimize_alpha = self.optimize_alpha;
-        let final_round = self.final_round;
-        let executed = self.executed.clone();
-        let best_candidate_size = self.best_candidate_size.clone();
-        let description = description.to_string();
-        // sends it off asynchronously for compression,
-        // but results will be collected via the message queue
-        #[cfg(feature = "parallel")]
-        let eval_send = self.eval_channel.0.clone();
-        rayon::spawn(move || {
-            executed.fetch_add(1, Relaxed);
-            let filters_iter = filters.par_iter().with_max_len(1);
-
-            // Updating of best result inside the parallel loop would require locks,
-            // which are dangerous to do in side Rayon's loop.
-            // Instead, only update (atomic) best size in real time,
-            // and the best result later without need for locks.
-            filters_iter.for_each(|filter| {
-                if deadline.passed() {
-                    return;
-                }
-                let (filtered, filter_used) = image.filter_image(filter.clone(), optimize_alpha);
-                let idat_data = deflater.deflate(&filtered, best_candidate_size.get());
-                if let Ok(idat_data) = idat_data {
-                    let estimated_output_size = image.estimated_output_size(&idat_data);
-                    trace!(
-                        "Eval: {}-bit {:23} {:8}   {} bytes",
-                        image.ihdr.bit_depth, description, filter, estimated_output_size
-                    );
-
-                    // Skip if it exceeds best known size. (This is important to ensure
-                    // the evaluator returns no result when all candidates are too large.)
-                    if let Some(max) = best_candidate_size.get() {
-                        if estimated_output_size > max {
-                            return;
-                        }
-                    }
-
-                    // We only need to retain the IDAT data in the final round
-                    let new = Candidate {
-                        image: image.clone(),
-                        idat_data: if final_round { Some(idat_data) } else { None },
-                        estimated_output_size,
-                        filter: filter.clone(),
-                        filter_used,
-                        nth,
-                    };
-                    best_candidate_size.set_min(estimated_output_size);
-
-                    #[cfg(feature = "parallel")]
-                    {
-                        eval_send.send(new).expect("send");
-                    }
-
-                    #[cfg(not(feature = "parallel"))]
-                    {
-                        match &mut *self.eval_best_candidate.borrow_mut() {
-                            Some(prev) if prev.cmp_key() < new.cmp_key() => {}
-                            best => *best = Some(new),
-                        }
-                    }
-                } else if let Err(PngError::DeflatedDataTooLong(size)) = idat_data {
-                    trace!(
-                        "Eval: {}-bit {:23} {:8}  >{} bytes",
-                        image.ihdr.bit_depth, description, filter, size
-                    );
-                }
-            });
-        });
-    }
-}

src/filters.rs

@@ -1,278 +1,148 @@
-use std::{fmt, fmt::Display, mem::transmute};
+pub fn filter_line(filter: u8, bpp: usize, data: &[u8], last_line: &[u8]) -> Vec<u8> {
-
+    let mut filtered = Vec::with_capacity(data.len());
-/// Filtering strategy for use in [`Options`][crate::Options]
+    match filter {
-#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone, Hash)]
+        0 => {
-pub enum FilterStrategy {
+            filtered.extend_from_slice(data);
-    /// Same filter for all rows
-    Basic(RowFilter),
-    /// Minimum sum of absolute differences
-    MinSum,
-    /// Shannon entropy
-    Entropy,
-    /// Count of distinct bigrams
-    Bigrams,
-    /// Shannon entropy of bigrams
-    BigEnt,
-    /// Deflate compression
-    Brute {
-        /// The number of lines to compress at once
-        num_lines: usize,
-        /// The compression level to use (1-12)
-        level: u8,
-    },
-    /// Predefined filter for each row
-    Predefined(Vec<RowFilter>),
-}
-
-impl FilterStrategy {
-    pub const NONE: Self = Self::Basic(RowFilter::None);
-    pub const SUB: Self = Self::Basic(RowFilter::Sub);
-    pub const UP: Self = Self::Basic(RowFilter::Up);
-    pub const AVERAGE: Self = Self::Basic(RowFilter::Average);
-    pub const PAETH: Self = Self::Basic(RowFilter::Paeth);
-}
-
-impl Display for FilterStrategy {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            Self::Basic(filter) => filter.fmt(f),
-            Self::MinSum => "MinSum".fmt(f),
-            Self::Entropy => "Entropy".fmt(f),
-            Self::Bigrams => "Bigrams".fmt(f),
-            Self::BigEnt => "BigEnt".fmt(f),
-            Self::Brute { .. } => "Brute".fmt(f),
-            Self::Predefined(_) => "Predefined".fmt(f),
         }
-    }
+        1 => {
-}
+            filtered.extend_from_slice(&data[0..bpp]);
-
+            filtered.extend(
-/// PNG delta filters
+                data.iter()
-#[repr(u8)]
+                    .skip(bpp)
-#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Hash)]
+                    .zip(data.iter())
-pub enum RowFilter {
+                    .map(|(cur, last)| cur.wrapping_sub(*last)),
-    None,
+            );
-    Sub,
-    Up,
-    Average,
-    Paeth,
-}
-
-impl TryFrom<u8> for RowFilter {
-    type Error = ();
-
-    fn try_from(value: u8) -> Result<Self, Self::Error> {
-        if value > 4 {
-            return Err(());
         }
-        unsafe { transmute(value as i8) }
+        2 => {
-    }
+            if last_line.is_empty() {
-}
+                filtered.extend_from_slice(data);
-
+            } else {
-impl Display for RowFilter {
+                filtered.extend(
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        Display::fmt(
-            match self {
-                Self::None => "None",
-                Self::Sub => "Sub",
-                Self::Up => "Up",
-                Self::Average => "Average",
-                Self::Paeth => "Paeth",
-            },
-            f,
-        )
-    }
-}
-
-impl RowFilter {
-    pub(crate) const ALL: [Self; 5] = [Self::None, Self::Sub, Self::Up, Self::Average, Self::Paeth];
-    pub(crate) const SINGLE_LINE: [Self; 2] = [Self::None, Self::Sub];
-
-    pub(crate) fn filter_line(
-        self,
-        bpp: usize,
-        data: &mut [u8],
-        prev_line: &[u8],
-        buf: &mut Vec<u8>,
-        alpha_bytes: usize,
-    ) {
-        assert!(data.len() >= bpp);
-        assert_eq!(data.len(), prev_line.len());
-
-        if alpha_bytes != 0 {
-            self.optimize_alpha(bpp, data, prev_line, bpp - alpha_bytes);
-        }
-
-        buf.clear();
-        buf.reserve(data.len() + 1);
-        buf.push(self as u8);
-        match self {
-            Self::None => {
-                buf.extend_from_slice(data);
-            }
-            Self::Sub => {
-                buf.extend_from_slice(&data[0..bpp]);
-                buf.extend(
                     data.iter()
-                        .skip(bpp)
+                        .zip(last_line.iter())
-                        .zip(data.iter())
                         .map(|(cur, last)| cur.wrapping_sub(*last)),
                 );
-            }
+            };
-            Self::Up => {
-                buf.extend(
-                    data.iter()
-                        .zip(prev_line.iter())
-                        .map(|(cur, last)| cur.wrapping_sub(*last)),
-                );
-            }
-            Self::Average => {
-                for (i, byte) in data.iter().enumerate() {
-                    buf.push(byte.wrapping_sub(i.checked_sub(bpp).map_or_else(
-                        || prev_line[i] >> 1,
-                        |x| ((u16::from(data[x]) + u16::from(prev_line[i])) >> 1) as u8,
-                    )));
-                }
-            }
-            Self::Paeth => {
-                for (i, byte) in data.iter().enumerate() {
-                    buf.push(byte.wrapping_sub(i.checked_sub(bpp).map_or_else(
-                        || prev_line[i],
-                        |x| paeth_predictor(data[x], prev_line[i], prev_line[x]),
-                    )));
-                }
-            }
         }
+        3 => for (i, byte) in data.iter().enumerate() {
+            if last_line.is_empty() {
+                filtered.push(match i.checked_sub(bpp) {
+                    Some(x) => byte.wrapping_sub(data[x] >> 1),
+                    None => *byte,
+                });
+            } else {
+                filtered.push(match i.checked_sub(bpp) {
+                    Some(x) => byte
+                        .wrapping_sub(((u16::from(data[x]) + u16::from(last_line[i])) >> 1) as u8),
+                    None => byte.wrapping_sub(last_line[i] >> 1),
+                });
+            };
+        },
+        4 => for (i, byte) in data.iter().enumerate() {
+            if last_line.is_empty() {
+                filtered.push(match i.checked_sub(bpp) {
+                    Some(x) => byte.wrapping_sub(data[x]),
+                    None => *byte,
+                });
+            } else {
+                filtered.push(match i.checked_sub(bpp) {
+                    Some(x) => {
+                        byte.wrapping_sub(paeth_predictor(data[x], last_line[i], last_line[x]))
+                    }
+                    None => byte.wrapping_sub(last_line[i]),
+                });
+            };
+        },
+        _ => unreachable!(),
     }
+    filtered
+}
 
-    // Optimize fully transparent pixels of a scanline such that they will be zeroed when filtered
+pub fn unfilter_line(filter: u8, bpp: usize, data: &[u8], last_line: &[u8]) -> Vec<u8> {
-    fn optimize_alpha(self, bpp: usize, data: &mut [u8], prev_line: &[u8], color_bytes: usize) {
+    let mut unfiltered = Vec::with_capacity(data.len());
-        if self == Self::None {
+    match filter {
-            // Assume transparent pixels already set to 0
+        0 => {
-            return;
+            unfiltered.extend_from_slice(data);
         }
-
+        1 => for (i, byte) in data.iter().enumerate() {
-        let mut pixels: Vec<_> = data.chunks_exact_mut(bpp).collect();
+            match i.checked_sub(bpp) {
-        let prev_pixels: Vec<_> = prev_line.chunks_exact(bpp).collect();
+                Some(x) => {
-        for i in 0..pixels.len() {
+                    let b = unfiltered[x];
-            if pixels[i].iter().skip(color_bytes).all(|b| *b == 0) {
+                    unfiltered.push(byte.wrapping_add(b));
-                // If the first pixel in the row is transparent, find the next non-transparent pixel and pretend
+                }
-                // it is the previous one. This can help improve effectiveness of the Sub and Paeth filters.
+                None => {
-                let prev = match i {
+                    unfiltered.push(*byte);
-                    0 => pixels
+                }
-                        .iter()
+            };
-                        .position(|px| px.iter().skip(color_bytes).any(|b| *b != 0))
+        },
-                        .unwrap_or(i),
+        2 => {
-                    _ => i - 1,
+            if last_line.is_empty() {
+                unfiltered.extend_from_slice(data);
+            } else {
+                unfiltered.extend(
+                    data.iter()
+                        .zip(last_line.iter())
+                        .map(|(cur, last)| cur.wrapping_add(*last)),
+                );
+            };
+        }
+        3 => {
+            for (i, byte) in data.iter().enumerate() {
+                if last_line.is_empty() {
+                    match i.checked_sub(bpp) {
+                        Some(x) => {
+                            let b = unfiltered[x];
+                            unfiltered.push(byte.wrapping_add(b >> 1));
+                        }
+                        None => {
+                            unfiltered.push(*byte);
+                        }
+                    };
+                } else {
+                    match i.checked_sub(bpp) {
+                        Some(x) => {
+                            let b = unfiltered[x];
+                            unfiltered.push(byte.wrapping_add(
+                                ((u16::from(b) + u16::from(last_line[i])) >> 1) as u8,
+                            ));
+                        }
+                        None => {
+                            unfiltered.push(byte.wrapping_add(last_line[i] >> 1));
+                        }
+                    };
                 };
-
-                // These assertions help eliminate a few bounds checks in the slice accesses below
-                assert!(prev < pixels.len());
-                assert!(i < prev_pixels.len());
-
-                match self {
-                    Self::None => unreachable!(),
-                    Self::Sub => {
-                        // The code below is roughly equivalent to pixels[i][0..color_bytes].copy_from_slice(&pixels[prev][0..color_bytes]),
-                        // if such a thing was possible to do without violating Rust aliasing rules. See:
-                        // https://users.rust-lang.org/t/problem-borrowing-two-elements-of-vec-mutably/21446/2
-
-                        if prev < i {
-                            let (pixels_head, pixels_tail) = pixels.split_at_mut(prev + 1);
-                            pixels_tail[i - prev - 1][0..color_bytes]
-                                .copy_from_slice(&pixels_head[prev][0..color_bytes]);
-                        } else if prev > i {
-                            let (pixels_head, pixels_tail) = pixels.split_at_mut(i + 1);
-                            pixels_head[i][0..color_bytes]
-                                .copy_from_slice(&pixels_tail[prev - i - 1][0..color_bytes]);
-                        } else {
-                            // If prev == i, we'd be copying the pixels onto themselves, which is useless
-                        }
-                    }
-                    Self::Up => {
-                        pixels[i][0..color_bytes].copy_from_slice(&prev_pixels[i][0..color_bytes]);
-                    }
-                    Self::Average => {
-                        for j in 0..color_bytes {
-                            pixels[i][j] = match i {
-                                0 => prev_pixels[i][j] >> 1,
-                                _ => {
-                                    ((u16::from(pixels[i - 1][j]) + u16::from(prev_pixels[i][j]))
-                                        >> 1) as u8
-                                }
-                            };
-                        }
-                    }
-                    Self::Paeth => {
-                        for j in 0..color_bytes {
-                            pixels[i][j] = match i {
-                                0 => pixels[prev][j].min(prev_pixels[i][j]),
-                                _ => paeth_predictor(
-                                    pixels[i - 1][j],
-                                    prev_pixels[i][j],
-                                    prev_pixels[i - 1][j],
-                                ),
-                            };
-                        }
-                    }
-                }
-            }
-        }
-    }
-
-    pub(crate) fn unfilter_line(
-        self,
-        bpp: usize,
-        data: &[u8],
-        prev_line: &[u8],
-        buf: &mut Vec<u8>,
-    ) {
-        buf.clear();
-        buf.reserve(data.len());
-        assert!(data.len() >= bpp);
-        assert_eq!(data.len(), prev_line.len());
-        match self {
-            Self::None => {
-                buf.extend_from_slice(data);
-            }
-            Self::Sub => {
-                for (i, &cur) in data.iter().enumerate() {
-                    let prev_byte = i.checked_sub(bpp).and_then(|x| buf.get(x).copied());
-                    buf.push(prev_byte.map_or(cur, |b| cur.wrapping_add(b)));
-                }
-            }
-            Self::Up => {
-                buf.extend(
-                    data.iter()
-                        .zip(prev_line)
-                        .map(|(&cur, &last)| cur.wrapping_add(last)),
-                );
-            }
-            Self::Average => {
-                for (i, (&cur, &last)) in data.iter().zip(prev_line).enumerate() {
-                    let prev_byte = i.checked_sub(bpp).and_then(|x| buf.get(x).copied());
-                    buf.push(cur.wrapping_add(prev_byte.map_or_else(
-                        || last >> 1,
-                        |b| ((u16::from(b) + u16::from(last)) >> 1) as u8,
-                    )));
-                }
-            }
-            Self::Paeth => {
-                for (i, (&cur, &up)) in data.iter().zip(prev_line).enumerate() {
-                    buf.push(
-                        match i
-                            .checked_sub(bpp)
-                            .map(|x| (buf.get(x).copied(), prev_line.get(x).copied()))
-                        {
-                            Some((Some(left), Some(left_up))) => {
-                                cur.wrapping_add(paeth_predictor(left, up, left_up))
-                            }
-                            _ => cur.wrapping_add(up),
-                        },
-                    );
-                }
             }
         }
+        4 => for (i, byte) in data.iter().enumerate() {
+            if last_line.is_empty() {
+                match i.checked_sub(bpp) {
+                    Some(x) => {
+                        let b = unfiltered[x];
+                        unfiltered.push(byte.wrapping_add(b));
+                    }
+                    None => {
+                        unfiltered.push(*byte);
+                    }
+                };
+            } else {
+                match i.checked_sub(bpp) {
+                    Some(x) => {
+                        let b = unfiltered[x];
+                        unfiltered.push(byte.wrapping_add(paeth_predictor(
+                            b,
+                            last_line[i],
+                            last_line[x],
+                        )));
+                    }
+                    None => {
+                        unfiltered.push(byte.wrapping_add(last_line[i]));
+                    }
+                };
+            };
+        },
+        _ => unreachable!(),
     }
+    unfiltered
 }
 
 fn paeth_predictor(a: u8, b: u8, c: u8) -> u8 {

src/headers.rs

@@ -1,16 +1,12 @@
-use indexmap::IndexSet;
+use byteorder::{BigEndian, ReadBytesExt};
-use log::{debug, trace, warn};
+use colors::{BitDepth, ColorType};
-use rgb::{RGB16, RGBA8};
+use crc::crc32;
+use error::PngError;
+use std::collections::HashSet;
+use std::io::Cursor;
+use PngResult;
 
-use crate::{
+#[derive(Debug, Clone, Copy)]
-    Deflater, Options, PngResult,
-    colors::{BitDepth, ColorType},
-    deflate::{crc32, inflate},
-    display_chunks::DISPLAY_CHUNKS,
-    error::PngError,
-};
-
-#[derive(Debug, Clone)]
 /// Headers from the IHDR chunk of the image
 pub struct IhdrData {
     /// The width of the image in pixels
@@ -21,81 +17,38 @@ pub struct IhdrData {
     pub color_type: ColorType,
     /// The bit depth of the image
     pub bit_depth: BitDepth,
-    /// Whether the image is interlaced
+    /// The compression method used for this image (0 for DEFLATE)
-    pub interlaced: bool,
+    pub compression: u8,
+    /// The filter mode used for this image (currently only 0 is valid)
+    pub filter: u8,
+    /// The interlacing mode of the image (0 = None, 1 = Adam7)
+    pub interlaced: u8,
 }
 
-impl IhdrData {
+#[derive(Debug, PartialEq, Clone)]
-    /// Bits per pixel
+/// Options to use for performing operations on headers (such as stripping)
-    #[must_use]
+pub enum Headers {
-    #[inline]
-    pub const fn bpp(&self) -> usize {
-        self.bit_depth as usize * self.color_type.channels_per_pixel() as usize
-    }
-
-    /// Byte length of IDAT that is correct for this IHDR
-    #[must_use]
-    pub const fn raw_data_size(&self) -> usize {
-        let w = self.width as usize;
-        let h = self.height as usize;
-        let bpp = self.bpp();
-
-        const fn bitmap_size(bpp: usize, w: usize, h: usize) -> usize {
-            (w * bpp).div_ceil(8) * h
-        }
-
-        if self.interlaced {
-            let mut size = bitmap_size(bpp, (w + 7) >> 3, (h + 7) >> 3) + ((h + 7) >> 3);
-            if w > 4 {
-                size += bitmap_size(bpp, (w + 3) >> 3, (h + 7) >> 3) + ((h + 7) >> 3);
-            }
-            size += bitmap_size(bpp, (w + 3) >> 2, (h + 3) >> 3) + ((h + 3) >> 3);
-            if w > 2 {
-                size += bitmap_size(bpp, (w + 1) >> 2, (h + 3) >> 2) + ((h + 3) >> 2);
-            }
-            size += bitmap_size(bpp, (w + 1) >> 1, (h + 1) >> 2) + ((h + 1) >> 2);
-            if w > 1 {
-                size += bitmap_size(bpp, w >> 1, (h + 1) >> 1) + ((h + 1) >> 1);
-            }
-            size + bitmap_size(bpp, w, h >> 1) + (h >> 1)
-        } else {
-            bitmap_size(bpp, w, h) + h
-        }
-    }
-}
-
-#[derive(Debug, Clone)]
-pub struct Chunk {
-    pub name: [u8; 4],
-    pub data: Vec<u8>,
-}
-
-/// [`Options`][crate::Options] to use when stripping chunks (metadata)
-#[derive(Debug, PartialEq, Eq, Clone)]
-pub enum StripChunks {
     /// None
-    ///
-    /// ...except caBX chunk if it contains a C2PA.org signature.
     None,
     /// Remove specific chunks
-    Strip(IndexSet<[u8; 4]>),
+    Strip(Vec<String>),
-    /// Remove all chunks that won't affect image display
+    /// Headers that won't affect rendering (all but cHRM, gAMA, iCCP, sBIT, sRGB, bKGD, hIST, pHYs, sPLT)
     Safe,
     /// Remove all non-critical chunks except these
-    Keep(IndexSet<[u8; 4]>),
+    Keep(HashSet<String>),
-    /// All non-critical chunks
+    /// All non-critical headers
     All,
 }
 
-impl StripChunks {
+#[derive(Debug, Clone)]
-    pub(crate) fn keep(&self, name: &[u8; 4]) -> bool {
+pub struct Header {
-        match &self {
+    pub key: String,
-            Self::None => true,
+    pub data: Vec<u8>,
-            Self::Keep(names) => names.contains(name),
+}
-            Self::Strip(names) => !names.contains(name),
+
-            Self::Safe => DISPLAY_CHUNKS.contains(name),
+impl Header {
-            Self::All => false,
+    pub fn new(key: String, data: Vec<u8>) -> Self {
-        }
+        Header { key, data }
     }
 }
 
@@ -107,319 +60,84 @@ pub fn file_header_is_valid(bytes: &[u8]) -> bool {
 }
 
 #[derive(Debug, Clone, Copy)]
-pub struct RawChunk<'a> {
+pub struct RawHeader<'a> {
     pub name: [u8; 4],
     pub data: &'a [u8],
 }
 
-impl RawChunk<'_> {
+pub fn parse_next_header<'a>(
-    // Is it a chunk for C2PA/CAI JUMBF metadata
-    pub(crate) fn is_c2pa(&self) -> bool {
-        if self.name == *b"caBX" {
-            if let Some((b"jumb", data)) = parse_jumbf_box(self.data) {
-                if let Some((b"jumd", data)) = parse_jumbf_box(data) {
-                    if data.get(..4) == Some(b"c2pa") {
-                        return true;
-                    }
-                }
-            }
-        }
-        false
-    }
-}
-
-fn parse_jumbf_box(data: &[u8]) -> Option<(&[u8], &[u8])> {
-    if data.len() < 8 {
-        return None;
-    }
-    let (len, rest) = data.split_at(4);
-    let len = read_be_u32(len) as usize;
-    if len < 8 || len > data.len() {
-        return None;
-    }
-    let (box_name, data) = rest.split_at(4);
-    let data = data.get(..len - 8)?;
-    Some((box_name, data))
-}
-
-pub fn parse_next_chunk<'a>(
     byte_data: &'a [u8],
     byte_offset: &mut usize,
     fix_errors: bool,
-) -> PngResult<Option<RawChunk<'a>>> {
+) -> PngResult<Option<RawHeader<'a>>> {
-    let length = read_be_u32(
+    let mut rdr = Cursor::new(
         byte_data
             .get(*byte_offset..*byte_offset + 4)
             .ok_or(PngError::TruncatedData)?,
     );
-    if byte_data.len() < *byte_offset + 12 + length as usize {
+    let length = rdr.read_u32::<BigEndian>().unwrap();
-        return Err(PngError::TruncatedData);
-    }
     *byte_offset += 4;
 
-    let chunk_start = *byte_offset;
+    let header_start = *byte_offset;
-    let chunk_name = &byte_data[chunk_start..chunk_start + 4];
+    let chunk_name = byte_data
+        .get(header_start..header_start + 4)
+        .ok_or(PngError::TruncatedData)?;
     if chunk_name == b"IEND" {
         // End of data
         return Ok(None);
     }
     *byte_offset += 4;
 
-    let data = &byte_data[*byte_offset..*byte_offset + length as usize];
+    let data = byte_data
+        .get(*byte_offset..*byte_offset + length as usize)
+        .ok_or(PngError::TruncatedData)?;
     *byte_offset += length as usize;
-    let crc = read_be_u32(&byte_data[*byte_offset..*byte_offset + 4]);
+    let mut rdr = Cursor::new(
+        byte_data
+            .get(*byte_offset..*byte_offset + 4)
+            .ok_or(PngError::TruncatedData)?,
+    );
+    let crc = rdr.read_u32::<BigEndian>().unwrap();
     *byte_offset += 4;
 
-    let chunk_bytes = &byte_data[chunk_start..chunk_start + 4 + length as usize];
+    let header_bytes = byte_data
-    if !fix_errors && crc32(chunk_bytes) != crc {
+        .get(header_start..header_start + 4 + length as usize)
-        return Err(PngError::CRCMismatch(chunk_name.try_into().unwrap()));
+        .ok_or(PngError::TruncatedData)?;
+    if !fix_errors && crc32::checksum_ieee(header_bytes) != crc {
+        return Err(PngError::new(&format!(
+            "CRC Mismatch in {} header; May be recoverable by using --fix",
+            String::from_utf8_lossy(chunk_name)
+        )));
     }
 
-    let name: [u8; 4] = chunk_name.try_into().unwrap();
+    let mut name = [0u8; 4];
-    Ok(Some(RawChunk { name, data }))
+    name.copy_from_slice(chunk_name);
+    Ok(Some(RawHeader { name, data }))
 }
 
-pub fn parse_ihdr_chunk(
+pub fn parse_ihdr_header(byte_data: &[u8]) -> PngResult<IhdrData> {
-    byte_data: &[u8],
+    let mut rdr = Cursor::new(&byte_data[0..8]);
-    palette_data: Option<Vec<u8>>,
-    trns_data: Option<Vec<u8>>,
-) -> PngResult<IhdrData> {
-    // This eliminates bounds checks for the rest of the function
-    let interlaced = byte_data.get(12).copied().ok_or(PngError::TruncatedData)?;
     Ok(IhdrData {
         color_type: match byte_data[9] {
-            0 => ColorType::Grayscale {
+            0 => ColorType::Grayscale,
-                transparent_shade: trns_data
+            2 => ColorType::RGB,
-                    .filter(|t| t.len() >= 2)
+            3 => ColorType::Indexed,
-                    .map(|t| read_be_u16(&t[0..2])),
-            },
-            2 => ColorType::RGB {
-                transparent_color: trns_data.filter(|t| t.len() >= 6).map(|t| RGB16 {
-                    r: read_be_u16(&t[0..2]),
-                    g: read_be_u16(&t[2..4]),
-                    b: read_be_u16(&t[4..6]),
-                }),
-            },
-            3 => ColorType::Indexed {
-                palette: palette_to_rgba(palette_data, trns_data).unwrap_or_default(),
-            },
             4 => ColorType::GrayscaleAlpha,
             6 => ColorType::RGBA,
-            _ => return Err(PngError::InvalidData),
+            _ => return Err(PngError::new("Unexpected color type in header")),
         },
-        bit_depth: byte_data[8].try_into()?,
+        bit_depth: match byte_data[8] {
-        width: read_be_u32(&byte_data[0..4]),
+            1 => BitDepth::One,
-        height: read_be_u32(&byte_data[4..8]),
+            2 => BitDepth::Two,
-        interlaced: match interlaced {
+            4 => BitDepth::Four,
-            0 => false,
+            8 => BitDepth::Eight,
-            1 => true,
+            16 => BitDepth::Sixteen,
-            _ => return Err(PngError::InvalidData),
+            _ => return Err(PngError::new("Unexpected bit depth in header")),
         },
+        width: rdr.read_u32::<BigEndian>().unwrap(),
+        height: rdr.read_u32::<BigEndian>().unwrap(),
+        compression: byte_data[10],
+        filter: byte_data[11],
+        interlaced: byte_data[12],
     })
 }
-
-/// Construct an RGBA palette from the raw palette and transparency data
-fn palette_to_rgba(
-    palette_data: Option<Vec<u8>>,
-    trns_data: Option<Vec<u8>>,
-) -> Result<Vec<RGBA8>, PngError> {
-    let palette_data = palette_data.ok_or(PngError::ChunkMissing("PLTE"))?;
-    let mut palette: Vec<_> = palette_data
-        .chunks_exact(3)
-        .map(|color| RGBA8::new(color[0], color[1], color[2], 255))
-        .collect();
-
-    if let Some(trns_data) = trns_data {
-        for (color, trns) in palette.iter_mut().zip(trns_data) {
-            color.a = trns;
-        }
-    }
-    Ok(palette)
-}
-
-#[inline]
-pub fn read_be_u16(bytes: &[u8]) -> u16 {
-    u16::from_be_bytes(bytes.try_into().unwrap())
-}
-
-#[inline]
-pub fn read_be_u32(bytes: &[u8]) -> u32 {
-    u32::from_be_bytes(bytes.try_into().unwrap())
-}
-
-/// Extract and decompress the ICC profile from an iCCP chunk
-pub fn extract_icc(iccp: &Chunk, max_size: Option<usize>) -> Option<Vec<u8>> {
-    // Skip (useless) profile name
-    let mut data = iccp.data.as_slice();
-    loop {
-        let (&n, rest) = data.split_first()?;
-        data = rest;
-        if n == 0 {
-            break;
-        }
-    }
-
-    let (&compression_method, compressed_data) = data.split_first()?;
-    if compression_method != 0 {
-        return None; // The profile is supposed to be compressed (method 0)
-    }
-    // Libdeflate works with a fixed size buffer. Since the decompressed size is unknown we have to
-    // guess the required buffer size. We allow a fairly generous 10x factor with a minimum of 1000.
-    let mut out_size = (compressed_data.len() * 10).max(1000);
-    // For sanity, impose a default limit of 1MB.
-    out_size = out_size.min(max_size.unwrap_or(1_000_000));
-    match inflate(compressed_data, out_size) {
-        Ok(icc) => Some(icc),
-        Err(e) => {
-            // Log the error so we can know if the buffer size needs to be adjusted
-            warn!("Failed to decompress icc: {e}");
-            None
-        }
-    }
-}
-
-/// Make an iCCP chunk by compressing the ICC profile
-pub fn make_iccp(icc: &[u8], deflater: Deflater, max_size: Option<usize>) -> PngResult<Chunk> {
-    let mut compressed = deflater.deflate(icc, max_size)?;
-    let mut data = Vec::with_capacity(compressed.len() + 5);
-    data.extend(b"icc"); // Profile name - generally unused, can be anything
-    data.extend([0, 0]); // Null separator, zlib compression method
-    data.append(&mut compressed);
-    Ok(Chunk {
-        name: *b"iCCP",
-        data,
-    })
-}
-
-/// If the profile is sRGB, extracts the rendering intent value from it
-pub fn srgb_rendering_intent(icc_data: &[u8]) -> Option<u8> {
-    let rendering_intent = *icc_data.get(67)?;
-
-    // The known profiles are the same as in libpng's `png_sRGB_checks`.
-    // The Profile ID header of ICC has a fixed layout,
-    // and is supposed to contain MD5 of profile data at this offset
-    match icc_data.get(84..100)? {
-        b"\x29\xf8\x3d\xde\xaf\xf2\x55\xae\x78\x42\xfa\xe4\xca\x83\x39\x0d"
-        | b"\xc9\x5b\xd6\x37\xe9\x5d\x8a\x3b\x0d\xf3\x8f\x99\xc1\x32\x03\x89"
-        | b"\xfc\x66\x33\x78\x37\xe2\x88\x6b\xfd\x72\xe9\x83\x82\x28\xf1\xb8"
-        | b"\x34\x56\x2a\xbf\x99\x4c\xcd\x06\x6d\x2c\x57\x21\xd0\xd6\x8c\x5d" => {
-            Some(rendering_intent)
-        }
-        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" => {
-            // Known-bad profiles are identified by their CRC
-            match (crc32(icc_data), icc_data.len()) {
-                (0x5d51_29ce, 3024) | (0x182e_a552, 3144) | (0xf29e_526d, 3144) => {
-                    Some(rendering_intent)
-                }
-                _ => None,
-            }
-        }
-        _ => None,
-    }
-}
-
-/// Process aux chunks and potentially adjust options before optimizing
-pub fn preprocess_chunks(aux_chunks: &mut Vec<Chunk>, opts: &mut Options) {
-    let has_srgb = aux_chunks.iter().any(|c| &c.name == b"sRGB");
-    // Grayscale conversion should not be performed if the image is not in the sRGB colorspace
-    // An sRGB profile would need to be stripped on conversion, so disallow if stripping is disabled
-    let mut allow_grayscale = !has_srgb || opts.strip != StripChunks::None;
-
-    if let Some(iccp_idx) = aux_chunks.iter().position(|c| &c.name == b"iCCP") {
-        allow_grayscale = false;
-        // See if we can replace an iCCP chunk with an sRGB chunk
-        let may_replace_iccp = opts.strip != StripChunks::None && opts.strip.keep(b"sRGB");
-        if may_replace_iccp && has_srgb {
-            // Files aren't supposed to have both chunks, so we chose to honor sRGB
-            trace!("Removing iCCP chunk due to conflict with sRGB chunk");
-            aux_chunks.remove(iccp_idx);
-            allow_grayscale = true;
-        } else if let Some(icc) = extract_icc(&aux_chunks[iccp_idx], opts.max_decompressed_size) {
-            let intent = if may_replace_iccp {
-                srgb_rendering_intent(&icc)
-            } else {
-                None
-            };
-            // sRGB-like profile can be replaced with an sRGB chunk with the same rendering intent
-            if let Some(intent) = intent {
-                trace!("Replacing iCCP chunk with equivalent sRGB chunk");
-                aux_chunks[iccp_idx] = Chunk {
-                    name: *b"sRGB",
-                    data: vec![intent],
-                };
-                allow_grayscale = true;
-            } else if opts.idat_recoding {
-                // Try recompressing the profile
-                let cur_len = aux_chunks[iccp_idx].data.len();
-                if let Ok(iccp) = make_iccp(&icc, opts.deflater, Some(cur_len - 1)) {
-                    debug!(
-                        "Recompressed iCCP chunk: {} ({} bytes decrease)",
-                        iccp.data.len(),
-                        cur_len - iccp.data.len()
-                    );
-                    aux_chunks[iccp_idx] = iccp;
-                }
-            }
-        }
-    }
-
-    if !allow_grayscale && opts.grayscale_reduction {
-        debug!("Disabling grayscale reduction due to presence of sRGB or iCCP chunk");
-        opts.grayscale_reduction = false;
-    }
-
-    // Check for APNG by presence of acTL chunk
-    if aux_chunks.iter().any(|c| &c.name == b"acTL") {
-        warn!("APNG detected, disabling all reductions");
-        opts.interlace = None;
-        opts.bit_depth_reduction = false;
-        opts.color_type_reduction = false;
-        opts.palette_reduction = false;
-        opts.grayscale_reduction = false;
-    }
-}
-
-/// Perform cleanup of certain aux chunks after optimization has been completed
-pub fn postprocess_chunks(aux_chunks: &mut Vec<Chunk>, ihdr: &IhdrData, orig_ihdr: &IhdrData) {
-    // If the depth/color type has changed, some chunks may be invalid and should be dropped
-    // While these could potentially be converted, they have no known use case today and are
-    // generally more trouble than they're worth
-    if orig_ihdr.bit_depth != ihdr.bit_depth || orig_ihdr.color_type != ihdr.color_type {
-        aux_chunks.retain(|c| {
-            let invalid = &c.name == b"bKGD" || &c.name == b"sBIT" || &c.name == b"hIST";
-            if invalid {
-                warn!(
-                    "Removing {} chunk as it no longer matches the image data",
-                    std::str::from_utf8(&c.name).unwrap()
-                );
-            }
-            !invalid
-        });
-    }
-
-    // Remove any sRGB or iCCP chunks if the image was converted to or from grayscale
-    if orig_ihdr.color_type.is_gray() != ihdr.color_type.is_gray() {
-        aux_chunks.retain(|c| {
-            let invalid = &c.name == b"sRGB" || &c.name == b"iCCP";
-            if invalid {
-                trace!(
-                    "Removing {} chunk as it no longer matches the color type",
-                    std::str::from_utf8(&c.name).unwrap()
-                );
-            }
-            !invalid
-        });
-    }
-
-    // Remove iDOT which will necessarily be invalid after successful optimization
-    aux_chunks.retain(|c| {
-        let invalid = &c.name == b"iDOT";
-        if invalid {
-            trace!(
-                "Removing {} chunk as it no longer matches the IDAT",
-                std::str::from_utf8(&c.name).unwrap()
-            );
-        }
-        !invalid
-    });
-}

src/interlace.rs

@@ -1,20 +1,51 @@
-use bitvec::prelude::*;
+use bit_vec::BitVec;
+use png::PngData;
 
-use crate::{headers::IhdrData, png::PngImage};
+pub fn interlace_image(png: &mut PngData) {
-
+    let mut passes: Vec<BitVec> = vec![BitVec::new(); 7];
-#[must_use]
+    let bits_per_pixel = png.ihdr_data.bit_depth.as_u8() * png.channels_per_pixel();
-pub fn interlace_image(png: &PngImage) -> PngImage {
+    for (index, line) in png.scan_lines().enumerate() {
-    let mut passes: Vec<BitVec<u8, Msb0>> = vec![BitVec::new(); 7];
+        match index % 8 {
-    let bits_per_pixel = png.ihdr.bpp();
+            // Add filter bytes to passes that will be in the output image
-    for (index, line) in png.scan_lines(false).enumerate() {
+            0 => {
-        let bit_vec = line.data.view_bits::<Msb0>();
+                passes[0].extend(BitVec::from_elem(8, false));
-        for (i, bit) in bit_vec.iter().by_vals().enumerate() {
+                if png.ihdr_data.width >= 5 {
+                    passes[1].extend(BitVec::from_elem(8, false));
+                }
+                if png.ihdr_data.width >= 3 {
+                    passes[3].extend(BitVec::from_elem(8, false));
+                }
+                if png.ihdr_data.width >= 2 {
+                    passes[5].extend(BitVec::from_elem(8, false));
+                }
+            }
+            4 => {
+                passes[2].extend(BitVec::from_elem(8, false));
+                if png.ihdr_data.width >= 3 {
+                    passes[3].extend(BitVec::from_elem(8, false));
+                }
+                if png.ihdr_data.width >= 2 {
+                    passes[5].extend(BitVec::from_elem(8, false));
+                }
+            }
+            2 | 6 => {
+                passes[4].extend(BitVec::from_elem(8, false));
+                if png.ihdr_data.width >= 2 {
+                    passes[5].extend(BitVec::from_elem(8, false));
+                }
+            }
+            _ => {
+                passes[6].extend(BitVec::from_elem(8, false));
+            }
+        }
+        let bit_vec = BitVec::from_bytes(&line.data);
+        for (i, bit) in bit_vec.iter().enumerate() {
             // Avoid moving padded 0's into new image
-            if i >= (png.ihdr.width as usize * bits_per_pixel) {
+            if i >= (png.ihdr_data.width * u32::from(bits_per_pixel)) as usize {
                 break;
             }
             // Copy pixels into interlaced passes
-            let pix_modulo = (i / bits_per_pixel) % 8;
+            let pix_modulo = (i / bits_per_pixel as usize) % 8;
             match index % 8 {
                 0 => match pix_modulo {
                     0 => passes[0].push(bit),
@@ -43,136 +74,64 @@ pub fn interlace_image(png: &PngImage) -> PngImage {
             }
         }
     }
-
+    let mut output = Vec::new();
-    let mut output = Vec::with_capacity(png.data.len());
     for pass in &passes {
-        output.extend_from_slice(pass.as_raw_slice());
+        output.extend(pass.to_bytes());
-    }
-
-    PngImage {
-        data: output,
-        ihdr: IhdrData {
-            color_type: png.ihdr.color_type.clone(),
-            interlaced: true,
-            ..png.ihdr
-        },
     }
+    png.raw_data = output;
 }
 
-pub fn deinterlace_image(png: &PngImage) -> PngImage {
+pub fn deinterlace_image(png: &mut PngData) {
-    PngImage {
+    let bits_per_pixel = png.ihdr_data.bit_depth.as_u8() * png.channels_per_pixel();
-        data: match png.ihdr.bpp() {
+    let bits_per_line = 8 + bits_per_pixel as usize * png.ihdr_data.width as usize;
-            8.. => deinterlace_bytes(png),
+    // Initialize each output line with a starting filter byte of 0
-            _ => deinterlace_bits(png),
+    // as well as some blank data
-        },
+    let mut lines: Vec<BitVec> =
-        ihdr: IhdrData {
+        vec![BitVec::from_elem(bits_per_line, false); png.ihdr_data.height as usize];
-            color_type: png.ihdr.color_type.clone(),
-            interlaced: false,
-            ..png.ihdr
-        },
-    }
-}
-
-/// Deinterlace by bits, for images with less than 8bpp
-fn deinterlace_bits(png: &PngImage) -> Vec<u8> {
-    let bits_per_pixel = png.ihdr.bpp();
-    let bits_per_line = bits_per_pixel * png.ihdr.width as usize;
-    // Initialize each output line with blank data
-    let mut lines: Vec<BitVec<u8, Msb0>> =
-        vec![bitvec![u8, Msb0; 0; bits_per_line]; png.ihdr.height as usize];
     let mut current_pass = 1;
     let mut pass_constants = interlaced_constants(current_pass);
     let mut current_y: usize = pass_constants.y_shift as usize;
-    for line in png.scan_lines(false) {
+    for line in png.scan_lines() {
-        let bit_vec = line.data.view_bits::<Msb0>();
+        let bit_vec = BitVec::from_bytes(&line.data);
-        let bits_in_line = (png.ihdr.width - u32::from(pass_constants.x_shift))
+        let bits_in_line = ((png.ihdr_data.width - u32::from(pass_constants.x_shift)) as f32
-            .div_ceil(u32::from(pass_constants.x_step)) as usize
+            / f32::from(pass_constants.x_step)).ceil() as usize
-            * bits_per_pixel;
+            * bits_per_pixel as usize;
-        for (i, bit) in bit_vec.iter().by_vals().enumerate() {
+        for (i, bit) in bit_vec.iter().enumerate() {
             // Avoid moving padded 0's into new image
             if i >= bits_in_line {
                 break;
             }
             let current_x: usize = pass_constants.x_shift as usize
-                + (i / bits_per_pixel) * pass_constants.x_step as usize;
+                + (i / bits_per_pixel as usize) * pass_constants.x_step as usize;
-            // Copy this bit into the output line
+            // Copy this bit into the output line, offset by 8 because of filter byte
-            let index = (i % bits_per_pixel) + current_x * bits_per_pixel;
+            let index = 8 + (i % bits_per_pixel as usize) + current_x * bits_per_pixel as usize;
             lines[current_y].set(index, bit);
         }
         // Calculate the next line and move to next pass if necessary
         current_y += pass_constants.y_step as usize;
-        if current_y >= png.ihdr.height as usize {
+        if current_y >= png.ihdr_data.height as usize {
-            if !increment_pass(&mut current_pass, &png.ihdr) {
+            if current_pass == 7 {
                 break;
             }
+            current_pass += 1;
+            if current_pass == 2 && png.ihdr_data.width <= 4 {
+                current_pass += 1;
+            }
+            if current_pass == 3 && png.ihdr_data.height <= 4 {
+                current_pass += 1;
+            }
             pass_constants = interlaced_constants(current_pass);
             current_y = pass_constants.y_shift as usize;
         }
     }
-    let mut output = Vec::with_capacity(png.data.len());
+    let mut output = Vec::new();
     for line in &mut lines {
         while line.len() % 8 != 0 {
             line.push(false);
         }
-        output.extend_from_slice(line.as_raw_slice());
+        output.extend(line.to_bytes());
     }
-    output
+    png.raw_data = output;
-}
-
-/// Deinterlace by bytes, for images with at least 8bpp
-fn deinterlace_bytes(png: &PngImage) -> Vec<u8> {
-    let bytes_per_pixel = png.ihdr.bpp() / 8;
-    let bytes_per_line = bytes_per_pixel * png.ihdr.width as usize;
-    // Initialize each output line with some blank data
-    let mut lines: Vec<Vec<u8>> = vec![vec![0; bytes_per_line]; png.ihdr.height as usize];
-    let mut current_pass = 1;
-    let mut pass_constants = interlaced_constants(current_pass);
-    let mut current_y: usize = pass_constants.y_shift as usize;
-    for line in png.scan_lines(false) {
-        for (i, byte) in line.data.iter().enumerate() {
-            let current_x: usize = pass_constants.x_shift as usize
-                + (i / bytes_per_pixel) * pass_constants.x_step as usize;
-            // Copy this byte into the output line
-            let index = (i % bytes_per_pixel) + current_x * bytes_per_pixel;
-            lines[current_y][index] = *byte;
-        }
-        // Calculate the next line and move to next pass if necessary
-        current_y += pass_constants.y_step as usize;
-        if current_y >= png.ihdr.height as usize {
-            if !increment_pass(&mut current_pass, &png.ihdr) {
-                break;
-            }
-            pass_constants = interlaced_constants(current_pass);
-            current_y = pass_constants.y_shift as usize;
-        }
-    }
-    lines.concat()
-}
-
-const fn increment_pass(current_pass: &mut u8, ihdr: &IhdrData) -> bool {
-    if *current_pass == 7 {
-        return false;
-    }
-    *current_pass += 1;
-    if *current_pass == 2 && ihdr.width <= 4 {
-        *current_pass += 1;
-    }
-    if *current_pass == 3 && ihdr.height <= 4 {
-        *current_pass += 1;
-    }
-    if *current_pass == 4 && ihdr.width <= 2 {
-        *current_pass += 1;
-    }
-    if *current_pass == 5 && ihdr.height <= 2 {
-        *current_pass += 1;
-    }
-    if *current_pass == 6 && ihdr.width == 1 {
-        *current_pass += 1;
-    }
-    if *current_pass == 7 && ihdr.height == 1 {
-        return false;
-    }
-    true
 }
 
 #[derive(Clone, Copy)]

src/options.rs

@@ -1,303 +0,0 @@
-use std::{
-    fmt,
-    path::{Path, PathBuf},
-    time::Duration,
-};
-
-use indexmap::{IndexSet, indexset};
-use log::warn;
-
-use crate::{deflate::Deflater, filters::FilterStrategy, headers::StripChunks};
-
-/// Write destination for [`optimize`][crate::optimize].
-/// You can use [`optimize_from_memory`](crate::optimize_from_memory) to avoid external I/O.
-#[derive(Clone, Debug)]
-pub enum OutFile {
-    /// Don't actually write any output, just calculate the best results.
-    None,
-    /// Write output to a file.
-    ///
-    /// * `path`: Path to write the output file. `None` means same as input.
-    /// * `preserve_attrs`: Ensure the output file has the same permissions & timestamps as the input file.
-    Path {
-        path: Option<PathBuf>,
-        preserve_attrs: bool,
-    },
-    /// Write to standard output.
-    StdOut,
-}
-
-impl OutFile {
-    /// Construct a new `OutFile` with the given path.
-    ///
-    /// This is a convenience method for `OutFile::Path { path: Some(path), preserve_attrs: false }`.
-    #[must_use]
-    pub const fn from_path(path: PathBuf) -> Self {
-        Self::Path {
-            path: Some(path),
-            preserve_attrs: false,
-        }
-    }
-
-    #[must_use]
-    pub fn path(&self) -> Option<&Path> {
-        match *self {
-            Self::Path {
-                path: Some(ref p), ..
-            } => Some(p.as_path()),
-            _ => None,
-        }
-    }
-}
-
-/// Where to read images from in [`optimize`][crate::optimize].
-/// You can use [`optimize_from_memory`](crate::optimize_from_memory) to avoid external I/O.
-#[derive(Clone, Debug)]
-pub enum InFile {
-    Path(PathBuf),
-    StdIn,
-}
-
-impl InFile {
-    #[must_use]
-    pub fn path(&self) -> Option<&Path> {
-        match *self {
-            Self::Path(ref p) => Some(p.as_path()),
-            Self::StdIn => None,
-        }
-    }
-}
-
-impl fmt::Display for InFile {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match *self {
-            Self::Path(ref p) => write!(f, "{}", p.display()),
-            Self::StdIn => f.write_str("stdin"),
-        }
-    }
-}
-
-impl<T: Into<PathBuf>> From<T> for InFile {
-    fn from(s: T) -> Self {
-        Self::Path(s.into())
-    }
-}
-
-#[derive(Clone, Debug)]
-/// Options controlling the output of the `optimize` function
-pub struct Options {
-    /// Attempt to fix errors when decoding the input file rather than returning an `Err`.
-    ///
-    /// Default: `false`
-    pub fix_errors: bool,
-    /// Write to output even if there was no improvement in compression.
-    ///
-    /// Default: `false`
-    pub force: bool,
-    /// Which `FilterStrategy` to try on the file
-    ///
-    /// Default: `None,Sub,Entropy,Bigrams`
-    pub filters: IndexSet<FilterStrategy>,
-    /// Whether to change the interlacing of the file.
-    ///
-    /// - `None` will not change the current interlacing.
-    /// - `Some(x)` will turn interlacing on or off.
-    ///
-    /// Default: `Some(false)`
-    pub interlace: Option<bool>,
-    /// Whether to allow transparent pixels to be altered to improve compression.
-    ///
-    /// Default: `false`
-    pub optimize_alpha: bool,
-    /// Whether to attempt bit depth reduction
-    ///
-    /// Default: `true`
-    pub bit_depth_reduction: bool,
-    /// Whether to attempt color type reduction
-    ///
-    /// Default: `true`
-    pub color_type_reduction: bool,
-    /// Whether to attempt palette reduction
-    ///
-    /// Default: `true`
-    pub palette_reduction: bool,
-    /// Whether to attempt grayscale reduction
-    ///
-    /// Default: `true`
-    pub grayscale_reduction: bool,
-    /// Whether to perform recoding of IDAT and other compressed chunks
-    ///
-    /// If any type of reduction is performed, IDAT recoding will be performed
-    /// regardless of this setting
-    ///
-    /// Default: `true`
-    pub idat_recoding: bool,
-    /// Whether to forcibly reduce 16-bit to 8-bit by scaling
-    ///
-    /// Default: `false`
-    pub scale_16: bool,
-    /// Which chunks to strip from the PNG file, if any
-    ///
-    /// Default: `None`
-    pub strip: StripChunks,
-    /// Which DEFLATE (zlib) algorithm to use
-    #[cfg_attr(feature = "zopfli", doc = "(e.g. Zopfli)")]
-    ///
-    /// Default: `Libdeflater`
-    pub deflater: Deflater,
-    /// Whether to use fast evaluation to pick the best filter
-    ///
-    /// Default: `true`
-    pub fast_evaluation: bool,
-    /// Maximum amount of time to spend on optimizations.
-    /// Further potential optimizations are skipped if the timeout is exceeded.
-    ///
-    /// Default: `None`
-    pub timeout: Option<Duration>,
-    /// Maximum decompressed size of the input IDAT.
-    /// If decompression would exceed this size, it will be rejected.
-    ///
-    /// Default: `None`
-    pub max_decompressed_size: Option<usize>,
-}
-
-impl Options {
-    #[must_use]
-    pub fn from_preset(level: u8) -> Self {
-        let opts = Self::default();
-        match level {
-            0 => opts.apply_preset_0(),
-            1 => opts.apply_preset_1(),
-            2 => opts.apply_preset_2(),
-            3 => opts.apply_preset_3(),
-            4 => opts.apply_preset_4(),
-            5 => opts.apply_preset_5(),
-            6 => opts.apply_preset_6(),
-            _ => {
-                warn!("Level 7 and above don't exist yet and are identical to level 6");
-                opts.apply_preset_6()
-            }
-        }
-    }
-
-    #[must_use]
-    pub fn max_compression() -> Self {
-        Self::from_preset(6)
-    }
-
-    // The following methods make assumptions that they are operating
-    // on an `Options` struct generated by the `default` method.
-    fn apply_preset_0(mut self) -> Self {
-        self.filters.clear();
-        self.deflater = Deflater::Libdeflater { compression: 5 };
-        self
-    }
-
-    fn apply_preset_1(mut self) -> Self {
-        self.filters.clear();
-        self.deflater = Deflater::Libdeflater { compression: 10 };
-        self
-    }
-
-    const fn apply_preset_2(self) -> Self {
-        self
-    }
-
-    fn apply_preset_3(mut self) -> Self {
-        self.fast_evaluation = false;
-        self.filters = indexset! {
-            FilterStrategy::NONE,
-            FilterStrategy::Bigrams,
-            FilterStrategy::BigEnt,
-            FilterStrategy::Brute {
-                num_lines: 3,
-                level: 1,
-            },
-        };
-        self
-    }
-
-    fn apply_preset_4(mut self) -> Self {
-        self.fast_evaluation = false;
-        self.filters = indexset! {
-            FilterStrategy::NONE,
-            FilterStrategy::Bigrams,
-            FilterStrategy::BigEnt,
-            FilterStrategy::Brute {
-                num_lines: 4,
-                level: 1,
-            },
-        };
-        self.deflater = Deflater::Libdeflater { compression: 12 };
-        self
-    }
-
-    fn apply_preset_5(mut self) -> Self {
-        self.fast_evaluation = false;
-        self.filters = indexset! {
-            FilterStrategy::NONE,
-            FilterStrategy::SUB,
-            FilterStrategy::UP,
-            FilterStrategy::MinSum,
-            FilterStrategy::Entropy,
-            FilterStrategy::Bigrams,
-            FilterStrategy::BigEnt,
-            FilterStrategy::Brute {
-                num_lines: 4,
-                level: 4,
-            },
-        };
-        self.deflater = Deflater::Libdeflater { compression: 12 };
-        self
-    }
-
-    fn apply_preset_6(mut self) -> Self {
-        self.fast_evaluation = false;
-        self.filters = indexset! {
-            FilterStrategy::NONE,
-            FilterStrategy::SUB,
-            FilterStrategy::UP,
-            FilterStrategy::AVERAGE,
-            FilterStrategy::PAETH,
-            FilterStrategy::MinSum,
-            FilterStrategy::Entropy,
-            FilterStrategy::Bigrams,
-            FilterStrategy::BigEnt,
-            FilterStrategy::Brute {
-                num_lines: 8,
-                level: 5,
-            },
-        };
-        self.deflater = Deflater::Libdeflater { compression: 12 };
-        self
-    }
-}
-
-impl Default for Options {
-    fn default() -> Self {
-        // Default settings based on -o 2 from the CLI interface
-        Self {
-            fix_errors: false,
-            force: false,
-            filters: indexset! {
-                FilterStrategy::NONE,
-                FilterStrategy::SUB,
-                FilterStrategy::Entropy,
-                FilterStrategy::Bigrams
-            },
-            interlace: Some(false),
-            optimize_alpha: false,
-            bit_depth_reduction: true,
-            color_type_reduction: true,
-            palette_reduction: true,
-            grayscale_reduction: true,
-            idat_recoding: true,
-            scale_16: false,
-            strip: StripChunks::None,
-            deflater: Deflater::Libdeflater { compression: 11 },
-            fast_evaluation: true,
-            timeout: None,
-            max_decompressed_size: None,
-        }
-    }
-}

src/png/apng.rs

@@ -0,0 +1,81 @@
+use byteorder::{BigEndian, ReadBytesExt};
+use std::io::Cursor;
+
+#[derive(Debug, Clone, Copy)]
+#[repr(u8)]
+pub enum DisposalType {
+    None = 0,
+    Background = 1,
+    Previous = 2,
+}
+
+impl From<u8> for DisposalType {
+    fn from(val: u8) -> Self {
+        match val {
+            0 => DisposalType::None,
+            1 => DisposalType::Background,
+            2 => DisposalType::Previous,
+            _ => panic!("Unrecognized disposal type"),
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy)]
+#[repr(u8)]
+pub enum BlendType {
+    Source = 0,
+    Over = 1,
+}
+
+impl From<u8> for BlendType {
+    fn from(val: u8) -> Self {
+        match val {
+            0 => BlendType::Source,
+            1 => BlendType::Over,
+            _ => panic!("Unrecognized blend type"),
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct ApngFrame {
+    pub sequence_number: u32,
+    pub width: u32,
+    pub height: u32,
+    pub x_offset: u32,
+    pub y_offset: u32,
+    pub delay_num: u16,
+    pub delay_den: u16,
+    pub dispose_op: DisposalType,
+    pub blend_op: BlendType,
+    /// The compressed, filtered data from the fdAT chunks
+    pub frame_data: Vec<u8>,
+    /// The uncompressed, optionally filtered data from the fdAT chunks
+    pub raw_data: Vec<u8>,
+}
+
+impl<'a> From<&'a [u8]> for ApngFrame {
+    /// Converts a fcTL header to an `ApngFrame`. Will panic if `data` is less than 26 bytes.
+    fn from(data: &[u8]) -> Self {
+        let mut cursor = Cursor::new(data);
+        ApngFrame {
+            sequence_number: cursor.read_u32::<BigEndian>().unwrap(),
+            width: cursor.read_u32::<BigEndian>().unwrap(),
+            height: cursor.read_u32::<BigEndian>().unwrap(),
+            x_offset: cursor.read_u32::<BigEndian>().unwrap(),
+            y_offset: cursor.read_u32::<BigEndian>().unwrap(),
+            delay_num: cursor.read_u16::<BigEndian>().unwrap(),
+            delay_den: cursor.read_u16::<BigEndian>().unwrap(),
+            dispose_op: cursor.read_u8().unwrap().into(),
+            blend_op: cursor.read_u8().unwrap().into(),
+            frame_data: Vec::new(),
+            raw_data: Vec::new(),
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy)]
+pub struct ApngHeaders {
+    pub frames: u32,
+    pub plays: u32,
+}

src/png/scan_lines.rs

@@ -1,168 +1,131 @@
-use crate::png::PngImage;
+use super::PngData;
 
-/// An iterator over the scan lines of a PNG image
 #[derive(Debug, Clone)]
+/// An iterator over the scan lines of a PNG image
 pub struct ScanLines<'a> {
-    iter: ScanLineRanges,
     /// A reference to the PNG image being iterated upon
-    raw_data: &'a [u8],
+    pub png: &'a PngData,
-    /// Whether the raw data contains filter bytes
+    pub start: usize,
-    has_filter: bool,
+    pub end: usize,
-}
+    /// Current pass number, and 0-indexed row within the pass
-
+    pub pass: Option<(u8, u32)>,
-impl<'a> ScanLines<'a> {
-    #[must_use]
-    pub fn new(png: &'a PngImage, has_filter: bool) -> Self {
-        Self {
-            iter: ScanLineRanges::new(png, has_filter),
-            raw_data: &png.data,
-            has_filter,
-        }
-    }
 }
 
 impl<'a> Iterator for ScanLines<'a> {
     type Item = ScanLine<'a>;
-
-    #[inline]
     fn next(&mut self) -> Option<Self::Item> {
-        let (len, pass, num_pixels) = self.iter.next()?;
+        if self.end == self.png.raw_data.len() {
-        debug_assert!(self.raw_data.len() >= len);
+            None
-        debug_assert!(!self.has_filter || len > 1);
+        } else if self.png.ihdr_data.interlaced == 1 {
-        // The data length should always be correct here but this check assures
-        // the compiler that it doesn't need to account for a potential panic
-        if self.raw_data.len() < len {
-            return None;
-        }
-        let (data, rest) = self.raw_data.split_at(len);
-        self.raw_data = rest;
-        let (&filter, data) = if self.has_filter {
-            data.split_first().unwrap()
-        } else {
-            (&0, data)
-        };
-        Some(ScanLine {
-            filter,
-            data,
-            pass,
-            num_pixels,
-        })
-    }
-}
-
-#[derive(Debug, Clone)]
-/// An iterator over the scan line locations of a PNG image
-struct ScanLineRanges {
-    /// Current pass number, and 0-indexed row within the pass
-    pass: Option<(u8, u32)>,
-    bits_per_pixel: usize,
-    width: u32,
-    height: u32,
-    left: usize,
-    has_filter: bool,
-}
-
-impl ScanLineRanges {
-    pub fn new(png: &PngImage, has_filter: bool) -> Self {
-        Self {
-            bits_per_pixel: png.ihdr.bpp(),
-            width: png.ihdr.width,
-            height: png.ihdr.height,
-            left: png.data.len(),
-            pass: if png.ihdr.interlaced {
-                Some((1, 0))
-            } else {
-                None
-            },
-            has_filter,
-        }
-    }
-}
-
-impl Iterator for ScanLineRanges {
-    type Item = (usize, Option<u8>, usize);
-
-    fn next(&mut self) -> Option<Self::Item> {
-        if self.left == 0 {
-            return None;
-        }
-        let (pixels_per_line, current_pass) = if let Some(ref mut pass) = self.pass {
             // Scanlines for interlaced PNG files
+            if self.pass.is_none() {
+                self.pass = Some((1, 0));
+            }
             // Handle edge cases for images smaller than 5 pixels in either direction
-            // No extra case needed for skipping pass 7 as this is already handled by the
+            if self.png.ihdr_data.width < 5 && self.pass.unwrap().0 == 2 {
-            // self.left == 0 check above
+                if let Some(pass) = self.pass.as_mut() {
-            if self.width < 5 && pass.0 == 2 {
+                    pass.0 = 3;
-                pass.0 = 3;
+                    pass.1 = 4;
-                pass.1 = 4;
+                }
             }
             // Intentionally keep these separate so that they can be applied one after another
-            if self.height < 5 && pass.0 == 3 {
+            if self.png.ihdr_data.height < 5 && self.pass.unwrap().0 == 3 {
-                pass.0 = 4;
+                if let Some(pass) = self.pass.as_mut() {
-                pass.1 = 0;
+                    pass.0 = 4;
+                    pass.1 = 0;
+                }
             }
-            if self.width < 3 && pass.0 == 4 {
+            let bits_per_pixel = u32::from(self.png.ihdr_data.bit_depth.as_u8())
-                pass.0 = 5;
+                * u32::from(self.png.channels_per_pixel());
-                pass.1 = 2;
+            let y_steps;
-            }
+            let pixels_factor;
-            if self.height < 3 && pass.0 == 5 {
+            match self.pass {
-                pass.0 = 6;
+                Some((1, _)) | Some((2, _)) => {
-                pass.1 = 0;
+                    pixels_factor = 8;
-            }
+                    y_steps = 8;
-            if self.width == 1 && pass.0 == 6 {
+                }
-                pass.0 = 7;
+                Some((3, _)) => {
-                pass.1 = 1;
+                    pixels_factor = 4;
-            }
+                    y_steps = 8;
-            let (pixels_factor, y_steps) = match pass.0 {
+                }
-                1 | 2 => (8, 8),
+                Some((4, _)) => {
-                3 => (4, 8),
+                    pixels_factor = 4;
-                4 => (4, 4),
+                    y_steps = 4;
-                5 => (2, 4),
+                }
-                6 => (2, 2),
+                Some((5, _)) => {
-                7 => (1, 2),
+                    pixels_factor = 2;
+                    y_steps = 4;
+                }
+                Some((6, _)) => {
+                    pixels_factor = 2;
+                    y_steps = 2;
+                }
+                Some((7, _)) => {
+                    pixels_factor = 1;
+                    y_steps = 2;
+                }
                 _ => unreachable!(),
-            };
+            }
-            let mut pixels_per_line = self.width / pixels_factor;
+            let mut pixels_per_line = self.png.ihdr_data.width / pixels_factor as u32;
             // Determine whether to add pixels if there is a final, incomplete 8x8 block
-            let gap = self.width % pixels_factor;
+            let gap = self.png.ihdr_data.width % pixels_factor;
-            match pass.0 {
+            if gap > 0 {
-                1 | 3 | 5 if gap > 0 => {
+                match self.pass.unwrap().0 {
-                    pixels_per_line += 1;
+                    1 | 3 | 5 => {
-                }
+                        pixels_per_line += 1;
-                2 if gap >= 5 => {
+                    }
-                    pixels_per_line += 1;
+                    2 if gap >= 5 => {
-                }
+                        pixels_per_line += 1;
-                4 if gap >= 3 => {
+                    }
-                    pixels_per_line += 1;
+                    4 if gap >= 3 => {
-                }
+                        pixels_per_line += 1;
-                6 if gap >= 2 => {
+                    }
-                    pixels_per_line += 1;
+                    6 if gap >= 2 => {
-                }
+                        pixels_per_line += 1;
-                _ => (),
+                    }
-            }
+                    _ => (),
-            let current_pass = Some(pass.0);
-            if pass.1 + y_steps >= self.height {
-                pass.0 += 1;
-                pass.1 = match pass.0 {
-                    3 => 4,
-                    5 => 2,
-                    7 => 1,
-                    _ => 0,
                 };
-            } else {
-                pass.1 += y_steps;
             }
-            (pixels_per_line, current_pass)
+            let current_pass = if let Some(pass) = self.pass {
+                Some(pass.0)
+            } else {
+                None
+            };
+            let bytes_per_line = ((pixels_per_line * bits_per_pixel + 7) / 8) as usize;
+            self.start = self.end;
+            self.end = self.start + bytes_per_line + 1;
+            if let Some(pass) = self.pass.as_mut() {
+                if pass.1 + y_steps >= self.png.ihdr_data.height {
+                    pass.0 += 1;
+                    pass.1 = match pass.0 {
+                        3 => 4,
+                        5 => 2,
+                        7 => 1,
+                        _ => 0,
+                    };
+                } else {
+                    pass.1 += y_steps;
+                }
+            }
+            Some(ScanLine {
+                filter: self.png.raw_data[self.start],
+                data: &self.png.raw_data[(self.start + 1)..self.end],
+                pass: current_pass,
+            })
         } else {
             // Standard, non-interlaced PNG scanlines
-            (self.width, None)
+            let bits_per_line = self.png.ihdr_data.width as usize
-        };
+                * self.png.ihdr_data.bit_depth.as_u8() as usize
-        let bits_per_line = pixels_per_line as usize * self.bits_per_pixel;
+                * self.png.channels_per_pixel() as usize;
-        let mut len = bits_per_line.div_ceil(8);
+            let bytes_per_line = (bits_per_line + 7) / 8 as usize;
-        if self.has_filter {
+            self.start = self.end;
-            len += 1;
+            self.end = self.start + bytes_per_line + 1;
+            Some(ScanLine {
+                filter: self.png.raw_data[self.start],
+                data: &self.png.raw_data[(self.start + 1)..self.end],
+                pass: None,
+            })
         }
-        self.left = self.left.checked_sub(len)?;
-        Some((len, current_pass, pixels_per_line as usize))
     }
 }
 
@@ -175,6 +138,4 @@ pub struct ScanLine<'a> {
     pub data: &'a [u8],
     /// The current pass if the image is interlaced
     pub pass: Option<u8>,
-    /// The number of pixels in the current scan line
-    pub num_pixels: usize,
 }

src/rayon.rs

@@ -1,81 +0,0 @@
-#![allow(dead_code)]
-
-pub mod prelude {
-    pub use super::*;
-}
-
-pub trait ParallelIterator: Iterator + Sized {
-    fn with_max_len(self, _l: usize) -> Self {
-        self
-    }
-    fn reduce_with<OP>(mut self, op: OP) -> Option<Self::Item>
-    where
-        OP: Fn(Self::Item, Self::Item) -> Self::Item + Sync,
-    {
-        self.next().map(|a| self.fold(a, op))
-    }
-}
-
-pub trait IntoParallelIterator {
-    type Iter: Iterator<Item = Self::Item>;
-    type Item: Send;
-    fn into_par_iter(self) -> Self::Iter;
-}
-
-pub trait IntoParallelRefIterator<'data> {
-    type Iter: Iterator<Item = Self::Item>;
-    type Item: Send + 'data;
-    fn par_iter(&'data self) -> Self::Iter;
-}
-
-pub trait IntoParallelRefMutIterator<'data> {
-    type Iter: ParallelIterator<Item = Self::Item>;
-    type Item: Send + 'data;
-    fn par_iter_mut(&'data mut self) -> Self::Iter;
-}
-
-impl<I: IntoIterator> IntoParallelIterator for I
-where
-    I::Item: Send,
-{
-    type Iter = I::IntoIter;
-    type Item = I::Item;
-
-    fn into_par_iter(self) -> Self::Iter {
-        self.into_iter()
-    }
-}
-
-impl<'data, I: 'data + ?Sized> IntoParallelRefIterator<'data> for I
-where
-    &'data I: IntoParallelIterator,
-{
-    type Iter = <&'data I as IntoParallelIterator>::Iter;
-    type Item = <&'data I as IntoParallelIterator>::Item;
-
-    fn par_iter(&'data self) -> Self::Iter {
-        self.into_par_iter()
-    }
-}
-
-impl<'data, I: 'data + ?Sized> IntoParallelRefMutIterator<'data> for I
-where
-    &'data mut I: IntoParallelIterator,
-{
-    type Iter = <&'data mut I as IntoParallelIterator>::Iter;
-    type Item = <&'data mut I as IntoParallelIterator>::Item;
-
-    fn par_iter_mut(&'data mut self) -> Self::Iter {
-        self.into_par_iter()
-    }
-}
-
-impl<I: Iterator> ParallelIterator for I {}
-
-pub fn join<A, B>(a: impl FnOnce() -> A, b: impl FnOnce() -> B) -> (A, B) {
-    (a(), b())
-}
-
-pub fn spawn<A>(a: impl FnOnce() -> A) -> A {
-    a()
-}

src/reduction/alpha.rs

@@ -1,108 +1,37 @@
-use rgb::RGB16;
+use png::PngData;
 
-use crate::{
+pub fn reduce_alpha_channel(png: &mut PngData, channels: u8) -> Option<Vec<u8>> {
-    colors::{BitDepth, ColorType},
+    let byte_depth = png.ihdr_data.bit_depth.as_u8() >> 3;
-    headers::IhdrData,
+    let bpp = channels * byte_depth;
-    png::PngImage,
+    let bpp_mask = bpp - 1;
-};
+    assert_eq!(0, bpp & bpp_mask);
-
-/// Clean the alpha channel by setting the color of all fully transparent pixels to black
-#[must_use]
-pub fn cleaned_alpha_channel(png: &PngImage) -> Option<PngImage> {
-    if !png.ihdr.color_type.has_alpha() {
-        return None;
-    }
-    let byte_depth = png.bytes_per_channel();
-    let bpp = png.channels_per_pixel() * byte_depth;
     let colored_bytes = bpp - byte_depth;
-
+    for line in png.scan_lines() {
-    let mut reduced = Vec::with_capacity(png.data.len());
+        for (i, &byte) in line.data.iter().enumerate() {
-    for pixel in png.data.chunks_exact(bpp) {
+            if i as u8 & bpp_mask >= colored_bytes && byte != 255 {
-        if pixel.iter().skip(colored_bytes).all(|b| *b == 0) {
+                return None;
-            reduced.resize(reduced.len() + bpp, 0);
-        } else {
-            reduced.extend_from_slice(pixel);
-        }
-    }
-
-    Some(PngImage {
-        data: reduced,
-        ihdr: png.ihdr.clone(),
-    })
-}
-
-#[must_use]
-pub fn reduced_alpha_channel(png: &PngImage, optimize_alpha: bool) -> Option<PngImage> {
-    if !png.ihdr.color_type.has_alpha() {
-        return None;
-    }
-    let byte_depth = png.bytes_per_channel();
-    let bpp = png.channels_per_pixel() * byte_depth;
-    let colored_bytes = bpp - byte_depth;
-
-    // If alpha optimisation is enabled, see if the image contains only fully opaque and fully transparent pixels.
-    // In case this occurs, we want to try and find an unused color we can use for the tRNS chunk.
-    // Rather than an exhaustive search, we will just keep track of 256 shades of gray, which should cover many cases.
-    let mut has_transparency = false;
-    let mut used_colors = vec![false; 256];
-
-    for pixel in png.data.chunks_exact(bpp) {
-        if optimize_alpha && pixel.iter().skip(colored_bytes).all(|b| *b == 0) {
-            // Fully transparent, we may be able to reduce with tRNS
-            has_transparency = true;
-        } else if pixel.iter().skip(colored_bytes).any(|b| *b != 255) {
-            // Partially transparent, the image is not reducible
-            return None;
-        } else if optimize_alpha && pixel.iter().take(colored_bytes).all(|b| *b == pixel[0]) {
-            // Opaque shade of gray, we can't use this color for tRNS
-            used_colors[pixel[0] as usize] = true;
-        }
-    }
-
-    let transparency_pixel = if has_transparency {
-        // For grayscale, start by checking 4 specific values in the hope that we may reduce depth
-        let unused = match png.ihdr.color_type {
-            ColorType::GrayscaleAlpha => [0x00, 0xFF, 0x55, 0xAA]
-                .into_iter()
-                .find(|&v| !used_colors[v as usize]),
-            _ => None,
-        }
-        .or_else(|| used_colors.iter().position(|&u| !u).map(|v| v as u8));
-        // If no unused color was found we will have to fail here
-        Some(unused?)
-    } else {
-        None
-    };
-
-    let mut raw_data = Vec::with_capacity(png.data.len());
-    for pixel in png.data.chunks_exact(bpp) {
-        match transparency_pixel {
-            Some(trns) if pixel.iter().skip(colored_bytes).all(|b| *b == 0) => {
-                raw_data.resize(raw_data.len() + colored_bytes, trns);
             }
-            _ => raw_data.extend_from_slice(&pixel[0..colored_bytes]),
         }
     }
 
-    // Construct the color type with appropriate transparency data
+    let mut reduced = Vec::with_capacity(png.raw_data.len());
-    let transparent = transparency_pixel.map(|trns| match png.ihdr.bit_depth {
+    for line in png.scan_lines() {
-        BitDepth::Sixteen => (u16::from(trns) << 8) | u16::from(trns),
+        reduced.push(line.filter);
-        _ => u16::from(trns),
+        for (i, &byte) in line.data.iter().enumerate() {
-    });
+            if i as u8 & bpp_mask >= colored_bytes {
-    let target_color_type = match png.ihdr.color_type {
+                continue;
-        ColorType::GrayscaleAlpha => ColorType::Grayscale {
+            } else {
-            transparent_shade: transparent,
+                reduced.push(byte);
-        },
+            }
-        _ => ColorType::RGB {
+        }
-            transparent_color: transparent.map(|t| RGB16::new(t, t, t)),
+    }
-        },
-    };
 
-    Some(PngImage {
+    // sBIT contains information about alpha channel's original depth,
-        data: raw_data,
+    // and alpha has just been removed
-        ihdr: IhdrData {
+    if let Some(sbit_header) = png.aux_headers.get_mut(b"sBIT") {
-            color_type: target_color_type,
+        assert_eq!(sbit_header.len(), channels as usize);
-            ..png.ihdr
+        sbit_header.pop();
-        },
+    }
-    })
+
+    Some(reduced)
 }

src/reduction/bit_depth.rs

@@ -1,230 +1,84 @@
-use crate::{
+use bit_vec::BitVec;
-    colors::{BitDepth, ColorType},
+use colors::{BitDepth, ColorType};
-    headers::IhdrData,
+use png::PngData;
-    png::PngImage,
-};
 
-/// Attempt to reduce a 16-bit image to 8-bit, returning the reduced image if successful
+const ONE_BIT_PERMUTATIONS: [u8; 2] = [0b0000_0000, 0b1111_1111];
-#[must_use]
+const TWO_BIT_PERMUTATIONS: [u8; 5] = [
-pub fn reduced_bit_depth_16_to_8(png: &PngImage, force_scale: bool) -> Option<PngImage> {
+    0b0000_0000,
-    if png.ihdr.bit_depth != BitDepth::Sixteen {
+    0b0000_1111,
-        return None;
+    0b0011_1100,
-    }
+    0b1111_0000,
+    0b1111_1111,
+];
+const FOUR_BIT_PERMUTATIONS: [u8; 11] = [
+    0b0000_0000,
+    0b0000_0011,
+    0b0000_1100,
+    0b0011_0000,
+    0b1100_0000,
+    0b0000_1111,
+    0b0011_1100,
+    0b1111_0000,
+    0b0011_1111,
+    0b1111_1100,
+    0b1111_1111,
+];
 
-    if force_scale {
+pub fn reduce_bit_depth_8_or_less(png: &mut PngData) -> bool {
-        return scaled_bit_depth_16_to_8(png);
+    let mut reduced = BitVec::with_capacity(png.raw_data.len() * 8);
-    }
+    let bit_depth: usize = png.ihdr_data.bit_depth.as_u8() as usize;
-
+    let mut allowed_bits = 1;
-    // Reduce from 16 to 8 bits per channel per pixel
+    for line in png.scan_lines() {
-    if png.data.chunks_exact(2).any(|pair| pair[0] != pair[1]) {
+        let bit_vec = BitVec::from_bytes(&line.data);
-        // Can't reduce
+        if png.ihdr_data.color_type == ColorType::Indexed {
-        return None;
+            for (i, bit) in bit_vec.iter().enumerate() {
-    }
+                let bit_index = bit_depth - (i % bit_depth);
-
+                if bit && bit_index > allowed_bits {
-    Some(PngImage {
+                    allowed_bits = bit_index.next_power_of_two();
-        data: png.data.chunks_exact(2).map(|pair| pair[0]).collect(),
+                    if allowed_bits == bit_depth {
-        ihdr: IhdrData {
+                        // Not reducable
-            color_type: png.ihdr.color_type.clone(),
+                        return false;
-            bit_depth: BitDepth::Eight,
-            ..png.ihdr
-        },
-    })
-}
-
-/// Forcibly reduce a 16-bit image to 8-bit by scaling, returning the reduced image if successful
-#[must_use]
-pub fn scaled_bit_depth_16_to_8(png: &PngImage) -> Option<PngImage> {
-    if png.ihdr.bit_depth != BitDepth::Sixteen {
-        return None;
-    }
-
-    // Reduce from 16 to 8 bits per channel per pixel by scaling when necessary
-    let data = png
-        .data
-        .chunks_exact(2)
-        .map(|pair| {
-            if pair[0] == pair[1] {
-                return pair[0];
-            }
-            // See: http://www.libpng.org/pub/png/spec/1.2/PNG-Decoders.html#D.Sample-depth-rescaling
-            // This allows values such as 0x00FF to be rounded to 0x01 rather than truncated to 0x00
-            let val = f32::from(u16::from_be_bytes([pair[0], pair[1]]));
-            (val * (255.0 / 65535.0)).round() as u8
-        })
-        .collect();
-
-    Some(PngImage {
-        data,
-        ihdr: IhdrData {
-            color_type: png.ihdr.color_type.clone(),
-            bit_depth: BitDepth::Eight,
-            ..png.ihdr
-        },
-    })
-}
-
-/// Attempt to reduce an 8-bit image to a lower bit depth, returning the reduced image if successful
-#[must_use]
-pub fn reduced_bit_depth_8_or_less(png: &PngImage) -> Option<PngImage> {
-    if png.ihdr.bit_depth != BitDepth::Eight || png.channels_per_pixel() != 1 {
-        return None;
-    }
-
-    let minimum_bits = if let ColorType::Indexed { palette } = &png.ihdr.color_type {
-        // We can easily determine minimum depth by the palette size
-        match palette.len() {
-            0..=2 => 1,
-            3..=4 => 2,
-            5..=16 => 4,
-            _ => return None,
-        }
-    } else {
-        let mut minimum_bits = 1;
-
-        // Finding minimum depth for grayscale is much more complicated
-        let mut mask = 1;
-        let mut divisions = 1..8;
-        for &b in &png.data {
-            if b == 0 || b == 255 {
-                continue;
-            }
-            'try_depth: loop {
-                // Align the first pixel division with the mask
-                let mut byte = b.rotate_left(minimum_bits as u32);
-                // Each potential division of this pixel must be identical to successfully reduce
-                let compare = byte & mask;
-                for _ in divisions.clone() {
-                    // Align the next division with the mask
-                    byte = byte.rotate_left(minimum_bits as u32);
-                    if byte & mask != compare {
-                        // This depth is not possible, try the next one up
-                        minimum_bits <<= 1;
-                        if minimum_bits == 8 {
-                            return None;
-                        }
-                        mask = (1 << minimum_bits) - 1;
-                        divisions = 1..(8 / minimum_bits);
-                        continue 'try_depth;
                     }
                 }
-                break;
             }
-        }
+        } else {
-
+            for byte in bit_vec.to_bytes() {
-        minimum_bits
+                while allowed_bits < bit_depth {
-    };
+                    let permutations: &[u8] = if allowed_bits == 1 {
-
+                        &ONE_BIT_PERMUTATIONS
-    let mut reduced = Vec::with_capacity(png.data.len());
+                    } else if allowed_bits == 2 {
-    let mask = (1 << minimum_bits) - 1;
+                        &TWO_BIT_PERMUTATIONS
-    for line in png.scan_lines(false) {
+                    } else if allowed_bits == 4 {
-        // Loop over the data in chunks that will produce 1 byte of output
+                        &FOUR_BIT_PERMUTATIONS
-        for chunk in line.data.chunks(8 / minimum_bits) {
+                    } else {
-            let mut new_byte = 0;
+                        return false;
-            let mut shift = 8;
+                    };
-            for byte in chunk {
+                    if permutations.iter().any(|perm| *perm == byte) {
-                shift -= minimum_bits;
+                        break;
-                // Take the low bits of the pixel and shift them into the output byte
+                    } else {
-                new_byte |= (byte & mask) << shift;
+                        allowed_bits <<= 1;
-            }
-            reduced.push(new_byte);
-        }
-    }
-
-    // If the image is grayscale we also need to reduce the transparency pixel
-    let color_type = if let ColorType::Grayscale {
-        transparent_shade: Some(trans),
-    } = png.ihdr.color_type
-    {
-        let reduced_trans = (trans & 0xFF) >> (8 - minimum_bits);
-        // Verify the reduction is valid by restoring back to original bit depth
-        let mut check = reduced_trans;
-        let mut bits = minimum_bits;
-        while bits < 8 {
-            check = (check << bits) | check;
-            bits <<= 1;
-        }
-        // If the transparency doesn't fit the new bit depth it is therefore unused - set it to None
-        ColorType::Grayscale {
-            transparent_shade: if trans == check {
-                Some(reduced_trans)
-            } else {
-                None
-            },
-        }
-    } else {
-        png.ihdr.color_type.clone()
-    };
-
-    Some(PngImage {
-        data: reduced,
-        ihdr: IhdrData {
-            color_type,
-            bit_depth: (minimum_bits as u8).try_into().unwrap(),
-            ..png.ihdr
-        },
-    })
-}
-
-/// Expand a 1/2/4-bit image to 8-bit, returning the expanded image if successful
-#[must_use]
-pub fn expanded_bit_depth_to_8(png: &PngImage) -> Option<PngImage> {
-    let bit_depth = png.ihdr.bit_depth as u32;
-    if bit_depth >= 8 {
-        return None;
-    }
-    // Calculate the current number of pixels per byte
-    let ppb = 8 / bit_depth;
-    let is_gray = matches!(png.ihdr.color_type, ColorType::Grayscale { .. });
-
-    let mut reduced = Vec::with_capacity((png.ihdr.width * png.ihdr.height) as usize);
-    let mut length = 0;
-    let mask = (1 << bit_depth) - 1;
-    for line in png.scan_lines(false) {
-        for &(mut byte) in line.data {
-            // Loop over each pixel in the byte
-            for _ in 0..ppb {
-                // Align the current pixel with the mask
-                byte = byte.rotate_left(bit_depth);
-                let mut val = byte & mask;
-                if is_gray {
-                    // Expand gray by repeating the bits
-                    let mut bits = bit_depth;
-                    while bits < 8 {
-                        val = (val << bits) | val;
-                        bits <<= 1;
                     }
                 }
-                reduced.push(val);
             }
         }
-        // Trim any overflow
-        length += line.num_pixels;
-        reduced.truncate(length);
     }
 
-    // If the image is grayscale we also need to expand the transparency pixel
+    for line in png.scan_lines() {
-    let color_type = if let ColorType::Grayscale {
+        reduced.extend(BitVec::from_bytes(&[line.filter]));
-        transparent_shade: Some(mut trans),
+        let bit_vec = BitVec::from_bytes(&line.data);
-    } = png.ihdr.color_type
+        for (i, bit) in bit_vec.iter().enumerate() {
-    {
+            let bit_index = bit_depth - (i % bit_depth);
-        let mut bits = bit_depth;
+            if bit_index <= allowed_bits {
-        while bits < 8 {
+                reduced.push(bit);
-            trans = (trans << bits) | trans;
+            }
-            bits <<= 1;
         }
-        ColorType::Grayscale {
+        // Pad end of line to get 8 bits per byte
-            transparent_shade: Some(trans),
+        while reduced.len() % 8 != 0 {
+            reduced.push(false);
         }
-    } else {
+    }
-        png.ihdr.color_type.clone()
-    };
 
-    Some(PngImage {
+    png.raw_data = reduced.to_bytes();
-        data: reduced,
+    png.ihdr_data.bit_depth = BitDepth::from_u8(allowed_bits as u8);
-        ihdr: IhdrData {
+    true
-            color_type,
-            bit_depth: BitDepth::Eight,
-            ..png.ihdr
-        },
-    })
 }

src/reduction/color.rs

@@ -1,206 +1,306 @@
-use std::hash::{BuildHasherDefault, Hash};
+use colors::{BitDepth, ColorType};
+use itertools::Itertools;
+use png::PngData;
 
-use indexmap::IndexSet;
+use super::alpha::reduce_alpha_channel;
-use rgb::{ComponentMap, FromSlice, RGB, RGBA, alt::Gray};
-use rustc_hash::FxHasher;
 
-use crate::{
+pub fn reduce_rgba_to_rgb(png: &mut PngData) -> bool {
-    colors::{BitDepth, ColorType},
+    if let Some(reduced) = reduce_alpha_channel(png, 4) {
-    headers::IhdrData,
+        png.raw_data = reduced;
-    png::PngImage,
+        png.ihdr_data.color_type = ColorType::RGB;
-};
+        true
-
+    } else {
-type FxIndexSet<V> = IndexSet<V, BuildHasherDefault<FxHasher>>;
+        false
-
+    }
-/// Maximum size difference between indexed and channels to consider a candidate for evaluation
+}
-pub const INDEXED_MAX_DIFF: usize = 20000;
+
-
+pub fn reduce_rgba_to_grayscale_alpha(png: &mut PngData) -> bool {
-fn build_palette<T>(
+    let mut reduced = Vec::with_capacity(png.raw_data.len());
-    iter: impl IntoIterator<Item = T>,
+    let byte_depth = png.ihdr_data.bit_depth.as_u8() >> 3;
-    reduced: &mut Vec<u8>,
+    let bpp = 4 * byte_depth;
-) -> Option<FxIndexSet<T>>
+    let bpp_mask = bpp - 1;
-where
+    assert_eq!(0, bpp & bpp_mask);
-    T: Eq + Hash,
+    let colored_bytes = bpp - byte_depth;
-{
+    for line in png.scan_lines() {
-    let mut palette = FxIndexSet::default();
+        reduced.push(line.filter);
-    palette.reserve(257);
+        let mut low_bytes = Vec::with_capacity(4);
-    for pixel in iter {
+        let mut high_bytes = Vec::with_capacity(4);
-        let (idx, _) = palette.insert_full(pixel);
+        let mut trans_bytes = Vec::with_capacity(byte_depth as usize);
-        if idx == 256 {
+        for (i, byte) in line.data.iter().enumerate() {
-            return None;
+            if i as u8 & bpp_mask < colored_bytes {
-        }
+                if byte_depth == 1 || i % 2 == 1 {
-        reduced.push(idx as u8);
+                    low_bytes.push(*byte);
-    }
+                } else {
-    Some(palette)
+                    high_bytes.push(*byte);
-}
+                }
-
+            } else {
-#[must_use]
+                trans_bytes.push(*byte);
-pub fn reduced_to_indexed(png: &PngImage, allow_grayscale: bool) -> Option<PngImage> {
+            }
-    if png.ihdr.bit_depth != BitDepth::Eight {
+
-        return None;
+            if (i as u8 & bpp_mask) == bpp - 1 {
-    }
+                if low_bytes.iter().unique().count() > 1 {
-    if matches!(png.ihdr.color_type, ColorType::Indexed { .. }) {
+                    return false;
-        return None;
+                }
-    }
+                if byte_depth == 2 {
-    if !allow_grayscale && png.ihdr.color_type.is_gray() {
+                    if high_bytes.iter().unique().count() > 1 {
-        return None;
+                        return false;
-    }
+                    }
-
+                    reduced.push(high_bytes[0]);
-    let mut raw_data = Vec::with_capacity(png.data.len() / png.channels_per_pixel());
+                    high_bytes.clear();
-    let palette: Vec<_> = match png.ihdr.color_type {
+                }
-        ColorType::Grayscale { transparent_shade } => {
+                reduced.push(low_bytes[0]);
-            let pmap = build_palette(png.data.as_gray().iter().copied(), &mut raw_data)?;
+                low_bytes.clear();
-            // Convert the Gray16 transparency to Gray8
+                reduced.extend_from_slice(&trans_bytes);
-            let transparency_pixel = transparent_shade.map(|t| Gray::from(t as u8));
+                trans_bytes.clear();
-            pmap.into_iter()
+            }
-                .map(|px| {
+        }
-                    RGB::from(px).with_alpha(if Some(px) == transparency_pixel {
+    }
-                        0
+
-                    } else {
+    if let Some(sbit_header) = png.aux_headers.get_mut(b"sBIT") {
-                        255
+        assert_eq!(sbit_header.len(), 4);
-                    })
+        sbit_header.remove(1);
-                })
+        sbit_header.remove(1);
-                .collect()
+    }
-        }
+    if let Some(bkgd_header) = png.aux_headers.get_mut(b"bKGD") {
-        ColorType::RGB { transparent_color } => {
+        assert_eq!(bkgd_header.len(), 6);
-            let pmap = build_palette(png.data.as_rgb().iter().copied(), &mut raw_data)?;
+        bkgd_header.truncate(2);
-            // Convert the RGB16 transparency to RGB8
+    }
-            let transparency_pixel = transparent_color.map(|t| t.map(|c| c as u8));
+
-            pmap.into_iter()
+    png.raw_data = reduced;
-                .map(|px| {
+    png.ihdr_data.color_type = ColorType::GrayscaleAlpha;
-                    px.with_alpha(if Some(px) == transparency_pixel {
+    true
-                        0
+}
-                    } else {
+
-                        255
+pub fn reduce_rgba_to_palette(png: &mut PngData) -> bool {
-                    })
+    if png.ihdr_data.bit_depth != BitDepth::Eight {
-                })
+        return false;
-                .collect()
+    }
-        }
+    let mut reduced = Vec::with_capacity(png.raw_data.len());
-        ColorType::GrayscaleAlpha => {
+    let mut palette = Vec::with_capacity(256);
-            let pmap = build_palette(png.data.as_gray_alpha().iter().copied(), &mut raw_data)?;
+    let bpp: usize = (4 * png.ihdr_data.bit_depth.as_u8() as usize) >> 3;
-            pmap.into_iter().map(RGBA::from).collect()
+    for line in png.scan_lines() {
-        }
+        reduced.push(line.filter);
-        ColorType::RGBA => {
+        let mut cur_pixel = Vec::with_capacity(bpp);
-            let pmap = build_palette(png.data.as_rgba().iter().copied(), &mut raw_data)?;
+        for (i, byte) in line.data.iter().enumerate() {
-            pmap.into_iter().collect()
+            cur_pixel.push(*byte);
-        }
+            if i % bpp == bpp - 1 {
-        _ => return None,
+                if let Some(idx) = palette.iter().position(|x| x == &cur_pixel) {
-    };
+                    reduced.push(idx as u8);
-
+                } else {
-    Some(PngImage {
+                    let len = palette.len();
-        data: raw_data,
+                    if len == 256 {
-        ihdr: IhdrData {
+                        return false;
-            color_type: ColorType::Indexed { palette },
+                    }
-            ..png.ihdr
+                    palette.push(cur_pixel);
-        },
+                    reduced.push(len as u8);
-    })
+                }
-}
+                cur_pixel = Vec::with_capacity(bpp);
-
+            }
-#[must_use]
+        }
-pub fn reduced_rgb_to_grayscale(png: &PngImage) -> Option<PngImage> {
+    }
-    if !png.ihdr.color_type.is_rgb() {
+
-        return None;
+    let mut color_palette = Vec::with_capacity(
-    }
+        palette.len() * 3 + if png.aux_headers.contains_key(b"bKGD") {
-
+            6
-    let mut reduced = Vec::with_capacity(png.data.len());
+        } else {
-    let byte_depth = png.bytes_per_channel();
+            0
-    let bpp = png.channels_per_pixel() * byte_depth;
+        },
-    let last_color = 2 * byte_depth;
+    );
-    for pixel in png.data.chunks_exact(bpp) {
+    let mut trans_palette = Vec::with_capacity(palette.len());
-        if byte_depth == 1 {
+    for color in &palette {
-            if pixel[0] != pixel[1] || pixel[1] != pixel[2] {
+        for (i, byte) in color.iter().enumerate() {
-                return None;
+            if i < 3 {
-            }
+                color_palette.push(*byte);
-        } else if pixel[0..2] != pixel[2..4] || pixel[2..4] != pixel[4..6] {
+            } else {
-            return None;
+                trans_palette.push(*byte);
-        }
+            }
-        reduced.extend_from_slice(&pixel[last_color..]);
+        }
-    }
+    }
-
+
-    let color_type = match png.ihdr.color_type {
+    let headers_size = color_palette.len() + trans_palette.len() + 8;
-        ColorType::RGB { transparent_color } => ColorType::Grayscale {
+    if reduced.len() + headers_size > png.raw_data.len() * 4 {
-            // Copy the transparent component if it is also gray
+        // Reduction would result in a larger image
-            transparent_shade: transparent_color
+        return false;
-                .filter(|t| t.r == t.g && t.g == t.b)
+    }
-                .map(|t| t.r),
+
-        },
+    if let Some(bkgd_header) = png.aux_headers.get_mut(b"bKGD") {
-        _ => ColorType::GrayscaleAlpha,
+        assert_eq!(bkgd_header.len(), 6);
-    };
+        let header_pixels = bkgd_header
-
+            .iter()
-    Some(PngImage {
+            .skip(1)
-        data: reduced,
+            .step(2)
-        ihdr: IhdrData {
+            .cloned()
-            color_type,
+            .collect::<Vec<u8>>();
-            ..png.ihdr
+        if let Some(entry) = color_palette
-        },
+            .chunks(3)
-    })
+            .position(|x| x == header_pixels.as_slice())
-}
+        {
-
+            *bkgd_header = vec![entry as u8];
-/// Attempt to convert indexed to a different color type, returning the resulting image if successful
+        } else if color_palette.len() / 3 == 256 {
-#[must_use]
+            return false;
-pub fn indexed_to_channels(
+        } else {
-    png: &PngImage,
+            let entry = color_palette.len() / 3;
-    allow_grayscale: bool,
+            color_palette.extend_from_slice(&header_pixels);
-    optimize_alpha: bool,
+            *bkgd_header = vec![entry as u8];
-) -> Option<PngImage> {
+        }
-    if png.ihdr.bit_depth != BitDepth::Eight {
+    }
-        return None;
+    if let Some(sbit_header) = png.aux_headers.get_mut(b"sBIT") {
-    }
+        assert_eq!(sbit_header.len(), 4);
-    let mut palette = match &png.ihdr.color_type {
+        sbit_header.pop();
-        ColorType::Indexed { palette } => palette.clone(),
+    }
-        _ => return None,
+
-    };
+    png.raw_data = reduced;
-
+    png.palette = Some(color_palette);
-    // Ensure fully transparent colors are black, which can help with grayscale conversion
+    if trans_palette.iter().any(|x| *x != 255) {
-    if optimize_alpha {
+        while let Some(255) = trans_palette.last().cloned() {
-        for color in &mut palette {
+            trans_palette.pop();
-            if color.a == 0 {
+        }
-                color.r = 0;
+        png.transparency_palette = Some(trans_palette);
-                color.g = 0;
+    } else {
-                color.b = 0;
+        png.transparency_palette = None;
-            }
+    }
-        }
+    png.ihdr_data.color_type = ColorType::Indexed;
-    }
+    true
-
+}
-    // Determine which channels are required
+
-    let is_gray = if allow_grayscale {
+pub fn reduce_rgb_to_palette(png: &mut PngData) -> bool {
-        palette.iter().all(|c| c.r == c.g && c.g == c.b)
+    if png.ihdr_data.bit_depth != BitDepth::Eight {
+        return false;
+    }
+    let mut reduced = Vec::with_capacity(png.raw_data.len());
+    let mut palette = Vec::with_capacity(256);
+    if let Some(ref trns) = png.transparency_pixel {
+        assert_eq!(trns.len(), 6);
+        if trns[0] != trns[1] || trns[2] != trns[3] || trns[4] != trns[5] {
+            return false;
+        }
+        palette.push(vec![trns[0], trns[2], trns[4]]);
+    }
+    let bpp: usize = (3 * png.ihdr_data.bit_depth.as_u8() as usize) >> 3;
+    for line in png.scan_lines() {
+        reduced.push(line.filter);
+        let mut cur_pixel = Vec::with_capacity(bpp);
+        for (i, byte) in line.data.iter().enumerate() {
+            cur_pixel.push(*byte);
+            if i % bpp == bpp - 1 {
+                if let Some(idx) = palette.iter().position(|x| x == &cur_pixel) {
+                    reduced.push(idx as u8);
+                } else {
+                    let len = palette.len();
+                    if len == 256 {
+                        return false;
+                    }
+                    palette.push(cur_pixel);
+                    reduced.push(len as u8);
+                }
+                cur_pixel = Vec::with_capacity(bpp);
+            }
+        }
+    }
+
+    let mut color_palette = Vec::with_capacity(palette.len() * 3);
+    for color in &palette {
+        color_palette.extend_from_slice(color);
+    }
+
+    let headers_size = color_palette.len() + 4;
+    if reduced.len() + headers_size > png.raw_data.len() * 3 {
+        // Reduction would result in a larger image
+        return false;
+    }
+
+    if let Some(bkgd_header) = png.aux_headers.get_mut(b"bKGD") {
+        assert_eq!(bkgd_header.len(), 6);
+        let header_pixels = bkgd_header
+            .iter()
+            .skip(1)
+            .step(2)
+            .cloned()
+            .collect::<Vec<u8>>();
+        if let Some(entry) = color_palette
+            .chunks(3)
+            .position(|x| x == header_pixels.as_slice())
+        {
+            *bkgd_header = vec![entry as u8];
+        } else if color_palette.len() == 255 {
+            return false;
+        } else {
+            let entry = color_palette.len() / 3;
+            color_palette.extend_from_slice(&header_pixels);
+            *bkgd_header = vec![entry as u8];
+        }
+    }
+
+    png.raw_data = reduced;
+    png.palette = Some(color_palette);
+    png.ihdr_data.color_type = ColorType::Indexed;
+    if png.transparency_pixel.is_some() {
+        png.transparency_pixel = None;
+        png.transparency_palette = Some(vec![0]);
+    };
+    true
+}
+
+pub fn reduce_rgb_to_grayscale(png: &mut PngData) -> bool {
+    let mut reduced = Vec::with_capacity(png.raw_data.len());
+    let byte_depth: u8 = png.ihdr_data.bit_depth.as_u8() >> 3;
+    let bpp: usize = 3 * byte_depth as usize;
+    let mut cur_pixel = Vec::with_capacity(bpp);
+    for line in png.scan_lines() {
+        reduced.push(line.filter);
+        for (i, byte) in line.data.iter().enumerate() {
+            cur_pixel.push(*byte);
+            if i % bpp == bpp - 1 {
+                if bpp == 3 {
+                    if cur_pixel.iter().unique().count() > 1 {
+                        return false;
+                    }
+                    reduced.push(cur_pixel[0]);
+                } else {
+                    let pixel_bytes = cur_pixel
+                        .iter()
+                        .step(2)
+                        .cloned()
+                        .zip(cur_pixel.iter().skip(1).step(2).cloned())
+                        .unique()
+                        .collect::<Vec<(u8, u8)>>();
+                    if pixel_bytes.len() > 1 {
+                        return false;
+                    }
+                    reduced.push(pixel_bytes[0].0);
+                    reduced.push(pixel_bytes[0].1);
+                }
+                cur_pixel.clear();
+            }
+        }
+    }
+    if let Some(ref mut trns) = png.transparency_pixel {
+        assert_eq!(trns.len(), 6);
+        if trns[0..2] != trns[2..4] || trns[2..4] != trns[4..6] {
+            return false;
+        }
+        *trns = trns[0..2].to_owned();
+    }
+    if let Some(sbit_header) = png.aux_headers.get_mut(b"sBIT") {
+        assert_eq!(sbit_header.len(), 3);
+        sbit_header.truncate(1);
+    }
+    if let Some(bkgd_header) = png.aux_headers.get_mut(b"bKGD") {
+        assert_eq!(bkgd_header.len(), 6);
+        bkgd_header.truncate(2);
+    }
+
+    png.raw_data = reduced;
+    png.ihdr_data.color_type = ColorType::Grayscale;
+    true
+}
+
+pub fn reduce_grayscale_alpha_to_grayscale(png: &mut PngData) -> bool {
+    if let Some(reduced) = reduce_alpha_channel(png, 2) {
+        png.raw_data = reduced;
+        png.ihdr_data.color_type = ColorType::Grayscale;
+        true
     } else {
         false
-    };
-    let has_alpha = palette.iter().any(|c| c.a != 255);
-    let color_type = match (is_gray, has_alpha) {
-        (false, true) => ColorType::RGBA,
-        (false, false) => ColorType::RGB {
-            transparent_color: None,
-        },
-        (true, true) => ColorType::GrayscaleAlpha,
-        (true, false) => ColorType::Grayscale {
-            transparent_shade: None,
-        },
-    };
-
-    // Don't proceed if output would be too much larger
-    let out_size = color_type.channels_per_pixel() as usize * png.data.len();
-    if out_size - png.data.len() > INDEXED_MAX_DIFF {
-        return None;
     }
-
-    // Construct the new data
-    let black = RGBA::new(0, 0, 0, 255);
-    let ch_start = if is_gray { 2 } else { 0 };
-    let ch_end = if has_alpha { 3 } else { 2 };
-    let mut data = Vec::with_capacity(out_size);
-    for b in &png.data {
-        let color = palette.get(*b as usize).unwrap_or(&black);
-        data.extend_from_slice(&color.as_ref()[ch_start..=ch_end]);
-    }
-
-    Some(PngImage {
-        ihdr: IhdrData {
-            color_type,
-            ..png.ihdr
-        },
-        data,
-    })
 }

src/reduction/mod.rs

@@ -1,203 +1,3 @@
-use std::sync::Arc;
+mod alpha;
-
-use crate::{ColorType, Deadline, Deflater, Options, evaluate::Evaluator, png::PngImage};
-
-pub mod alpha;
-use crate::alpha::*;
 pub mod bit_depth;
-use crate::bit_depth::*;
 pub mod color;
-use crate::color::*;
-pub mod palette;
-use crate::palette::*;
-
-pub(crate) fn perform_reductions(
-    mut png: Arc<PngImage>,
-    opts: &Options,
-    deadline: &Deadline,
-    eval: &Evaluator,
-) -> Arc<PngImage> {
-    let mut evaluation_added = false;
-
-    // At low compression levels, skip some transformations which are less likely to be effective
-    // This currently affects optimization presets 0-2
-    let cheap = match opts.deflater {
-        Deflater::Libdeflater { compression } => compression < 12 && opts.fast_evaluation,
-        _ => false,
-    };
-
-    // Interlacing must be processed first in order to evaluate the rest correctly
-    if let Some(interlacing) = opts.interlace {
-        if let Some(reduced) = png.change_interlacing(interlacing) {
-            png = Arc::new(reduced);
-        }
-    }
-
-    // If alpha optimization is enabled, clean the alpha channel before continuing
-    // This can allow some color type reductions which may not have been possible otherwise
-    if opts.optimize_alpha && !deadline.passed() {
-        if let Some(reduced) = cleaned_alpha_channel(&png) {
-            png = Arc::new(reduced);
-        }
-    }
-
-    // Attempt to reduce 16-bit to 8-bit
-    // This is just removal of bytes and does not need to be evaluated
-    if opts.bit_depth_reduction && !deadline.passed() {
-        if let Some(reduced) = reduced_bit_depth_16_to_8(&png, opts.scale_16) {
-            png = Arc::new(reduced);
-        }
-    }
-
-    // Attempt to reduce RGB to grayscale
-    // This is just removal of bytes and does not need to be evaluated
-    if opts.color_type_reduction && opts.grayscale_reduction && !deadline.passed() {
-        if let Some(reduced) = reduced_rgb_to_grayscale(&png) {
-            png = Arc::new(reduced);
-        }
-    }
-
-    // Attempt to expand the bit depth to 8
-    // This does need to be evaluated but will be done so later when it gets reduced again
-    if opts.bit_depth_reduction && !deadline.passed() {
-        if let Some(reduced) = expanded_bit_depth_to_8(&png) {
-            png = Arc::new(reduced);
-        }
-    }
-
-    // Now retain the current png for the evaluator baseline
-    // It will only be entered into the evaluator if there are also others to evaluate
-    let mut baseline = png.clone();
-
-    // Attempt to reduce and sort the palette
-    if opts.palette_reduction && !deadline.passed() {
-        if let Some(reduced) = reduced_palette(&png, opts.optimize_alpha) {
-            png = Arc::new(reduced);
-            // If the palette was reduced but the data is unchanged then this should become the baseline
-            if png.data == baseline.data {
-                baseline = png.clone();
-            }
-        }
-        if let Some(reduced) = sorted_palette(&png) {
-            png = Arc::new(reduced);
-        }
-        // If either action changed the data then enter this into the evaluator
-        if !Arc::ptr_eq(&png, &baseline) {
-            eval.try_image_with_description(png.clone(), "Indexed (luma sort)");
-            evaluation_added = true;
-        }
-    }
-
-    // Attempt alpha removal
-    if opts.color_type_reduction && !deadline.passed() {
-        if let Some(reduced) = reduced_alpha_channel(&png, opts.optimize_alpha) {
-            png = Arc::new(reduced);
-            // For small differences, if a tRNS chunk is required then enter this into the evaluator
-            // Otherwise it is mostly just removal of bytes and should become the baseline
-            if png.ihdr.color_type.has_trns() && baseline.data.len() - png.data.len() <= 1000 {
-                eval.try_image(png.clone());
-                evaluation_added = true;
-            } else {
-                baseline = png.clone();
-            }
-        }
-    }
-
-    // Attempt to convert from indexed to channels
-    // This may give a better result due to dropping the PLTE chunk
-    if !cheap && opts.color_type_reduction && !deadline.passed() {
-        if let Some(reduced) =
-            indexed_to_channels(&png, opts.grayscale_reduction, opts.optimize_alpha)
-        {
-            // This result should not be passed on to subsequent reductions
-            eval.try_image(Arc::new(reduced));
-            evaluation_added = true;
-        }
-    }
-
-    // Attempt to reduce to indexed
-    // Keep the existing `png` var in case it is grayscale - we can test both for depth reduction later
-    let mut indexed = None;
-    if opts.color_type_reduction && opts.palette_reduction && !deadline.passed() {
-        if let Some(reduced) = reduced_to_indexed(&png, opts.grayscale_reduction) {
-            // Make sure the palette gets sorted (but don't bother evaluating both results)
-            let new = Arc::new(sorted_palette(&reduced).unwrap_or(reduced));
-            // For relatively small differences, enter this into the evaluator
-            // Otherwise we're confident enough for it to become the baseline
-            if png.data.len() - new.data.len() <= INDEXED_MAX_DIFF {
-                eval.try_image_with_description(new.clone(), "Indexed (luma sort)");
-                evaluation_added = true;
-            } else {
-                baseline = new.clone();
-            }
-            indexed = Some(new);
-        }
-    }
-
-    // Attempt additional palette sorting techniques
-    if !cheap && opts.palette_reduction {
-        // Collect a list of palettes so we can avoid evaluating the same one twice
-        let mut palettes = Vec::new();
-        if let ColorType::Indexed { palette } = &baseline.ihdr.color_type {
-            palettes.push(palette.clone());
-        }
-        // Make sure we use the `indexed` var as input if it exists
-        // This one doesn't need to be kept in the palette list as the sorters will fail if there's no change
-        let input = indexed.as_ref().unwrap_or(&png);
-
-        // Attempt to sort the palette using the battiato method
-        if !deadline.passed() {
-            if let Some(reduced) = sorted_palette_battiato(input) {
-                if let ColorType::Indexed { palette } = &reduced.ihdr.color_type {
-                    if !palettes.contains(palette) {
-                        palettes.push(palette.clone());
-                        eval.try_image_with_description(
-                            Arc::new(reduced),
-                            "Indexed (battiato sort)",
-                        );
-                        evaluation_added = true;
-                    }
-                }
-            }
-        }
-
-        // Attempt to sort the palette using the mzeng method
-        if !deadline.passed() {
-            if let Some(reduced) = sorted_palette_mzeng(input) {
-                if let ColorType::Indexed { palette } = &reduced.ihdr.color_type {
-                    if !palettes.contains(palette) {
-                        palettes.push(palette.clone());
-                        eval.try_image_with_description(Arc::new(reduced), "Indexed (mzeng sort)");
-                        evaluation_added = true;
-                    }
-                }
-            }
-        }
-    }
-
-    // Attempt to reduce to a lower bit depth
-    if opts.bit_depth_reduction && !deadline.passed() {
-        // First try the `png` var
-        let reduced = reduced_bit_depth_8_or_less(&png);
-        // Then try the `indexed` var, unless we're doing cheap evaluations and already have a reduction
-        if (!cheap || reduced.is_none()) && !deadline.passed() {
-            if let Some(indexed) = indexed.and_then(|png| reduced_bit_depth_8_or_less(&png)) {
-                // Only evaluate this if it's different from the first result (which must be grayscale if it exists)
-                if reduced.as_ref().is_none_or(|r| r.data != indexed.data) {
-                    eval.try_image(Arc::new(indexed));
-                    evaluation_added = true;
-                }
-            }
-        }
-        // Enter the first result into the evaluator
-        if let Some(reduced) = reduced {
-            eval.try_image(Arc::new(reduced));
-            evaluation_added = true;
-        }
-    }
-
-    if evaluation_added {
-        eval.try_image(baseline.clone());
-    }
-    baseline
-}

src/reduction/palette.rs

@@ -1,439 +0,0 @@
-use indexmap::IndexSet;
-use rgb::RGBA8;
-
-use crate::{
-    colors::{BitDepth, ColorType},
-    headers::IhdrData,
-    png::{PngImage, scan_lines::ScanLine},
-};
-
-/// Attempt to reduce the number of colors in the palette, returning the reduced image if successful
-#[must_use]
-pub fn reduced_palette(png: &PngImage, optimize_alpha: bool) -> Option<PngImage> {
-    if png.ihdr.bit_depth != BitDepth::Eight {
-        return None;
-    }
-    let ColorType::Indexed { palette } = &png.ihdr.color_type else {
-        return None;
-    };
-
-    let mut used = [false; 256];
-    for &byte in &png.data {
-        used[byte as usize] = true;
-    }
-
-    let black = RGBA8::new(0, 0, 0, 255);
-    let mut condensed = IndexSet::with_capacity(palette.len());
-    let mut byte_map = [0; 256];
-    let mut did_change = false;
-    for (i, used) in used.iter().enumerate() {
-        if !used {
-            continue;
-        }
-        // There are invalid files that use pixel indices beyond palette size
-        let color = *palette.get(i).unwrap_or(&black);
-        byte_map[i] = add_color_to_set(color, &mut condensed, optimize_alpha);
-        if byte_map[i] as usize != i {
-            did_change = true;
-        }
-    }
-
-    let data = if did_change {
-        // Reassign data bytes to new indices
-        png.data.iter().map(|b| byte_map[*b as usize]).collect()
-    } else if condensed.len() != palette.len() {
-        // Data is unchanged but palette is different size
-        // Note the new palette could potentially be larger if the original had a missing entry
-        png.data.clone()
-    } else {
-        // Nothing has changed
-        return None;
-    };
-
-    let palette: Vec<_> = condensed.into_iter().collect();
-
-    Some(PngImage {
-        ihdr: IhdrData {
-            color_type: ColorType::Indexed { palette },
-            ..png.ihdr
-        },
-        data,
-    })
-}
-
-fn add_color_to_set(mut color: RGBA8, set: &mut IndexSet<RGBA8>, optimize_alpha: bool) -> u8 {
-    // If there are multiple fully transparent entries, reduce them into one
-    if optimize_alpha && color.a == 0 {
-        color.r = 0;
-        color.g = 0;
-        color.b = 0;
-    }
-    let (idx, _) = set.insert_full(color);
-    idx as u8
-}
-
-/// Attempt to sort the colors in the palette by luma, returning the sorted image if successful
-#[must_use]
-pub fn sorted_palette(png: &PngImage) -> Option<PngImage> {
-    if png.ihdr.bit_depth != BitDepth::Eight {
-        return None;
-    }
-    let palette = match &png.ihdr.color_type {
-        ColorType::Indexed { palette } if palette.len() > 1 => palette,
-        _ => return None,
-    };
-
-    let mut enumerated: Vec<_> = palette.iter().enumerate().collect();
-    // Put the most popular edge color first, which can help slightly if the filter bytes are 0
-    let keep_first = most_popular_edge_color(palette.len(), png);
-    let first = keep_first.map(|f| enumerated.remove(f));
-
-    // Sort the palette
-    enumerated.sort_by(|a, b| {
-        // Sort by ascending alpha and descending luma
-        let color_val = |color: &RGBA8| {
-            let a = i32::from(color.a);
-            // Put 7 high bits of alpha first, then luma, then low bit of alpha
-            // This provides notable improvement in images with a lot of alpha
-            ((a & 0xFE) << 18) + (a & 0x01)
-            // These are coefficients for standard sRGB to luma conversion
-            - i32::from(color.r) * 299
-            - i32::from(color.g) * 587
-            - i32::from(color.b) * 114
-        };
-        color_val(a.1).cmp(&color_val(b.1))
-    });
-    if let Some(first) = first {
-        enumerated.insert(0, first);
-    }
-
-    // Extract the new palette and determine if anything changed
-    let (remapping, palette): (Vec<_>, Vec<RGBA8>) = enumerated.into_iter().unzip();
-    if remapping.iter().enumerate().all(|(a, b)| a == *b) {
-        return None;
-    }
-
-    // Construct the new mapping and convert the data
-    let mut byte_map = [0; 256];
-    for (i, &v) in remapping.iter().enumerate() {
-        byte_map[v] = i as u8;
-    }
-    let data = png.data.iter().map(|&b| byte_map[b as usize]).collect();
-
-    Some(PngImage {
-        ihdr: IhdrData {
-            color_type: ColorType::Indexed { palette },
-            ..png.ihdr
-        },
-        data,
-    })
-}
-
-/// Sort the colors in the palette using the mzeng technique, returning the sorted image if successful
-#[must_use]
-pub fn sorted_palette_mzeng(png: &PngImage) -> Option<PngImage> {
-    // Interlacing not currently supported
-    if png.ihdr.bit_depth != BitDepth::Eight || png.ihdr.interlaced {
-        return None;
-    }
-    let palette = match &png.ihdr.color_type {
-        // Images with only two colors will remain unchanged from previous luma sort
-        ColorType::Indexed { palette } if palette.len() > 2 => palette,
-        _ => return None,
-    };
-
-    let matrix = co_occurrence_matrix(palette.len(), png);
-    let edges = weighted_edges(&matrix);
-    let mut remapping = mzeng_reindex(palette.len(), edges, &matrix);
-
-    apply_most_popular_color(png, &mut remapping);
-
-    apply_palette_reorder(png, &remapping)
-}
-
-/// Sort the colors in the palette using the battiato technique, returning the sorted image if successful
-#[must_use]
-pub fn sorted_palette_battiato(png: &PngImage) -> Option<PngImage> {
-    // Interlacing not currently supported
-    if png.ihdr.bit_depth != BitDepth::Eight || png.ihdr.interlaced {
-        return None;
-    }
-    let palette = match &png.ihdr.color_type {
-        // Images with only two colors will remain unchanged from previous luma sort
-        ColorType::Indexed { palette } if palette.len() > 2 => palette,
-        _ => return None,
-    };
-
-    let matrix = co_occurrence_matrix(palette.len(), png);
-    let edges = weighted_edges(&matrix);
-    let mut remapping = battiato_reindex(palette.len(), edges);
-
-    apply_most_popular_color(png, &mut remapping);
-
-    apply_palette_reorder(png, &remapping)
-}
-
-// Apply the palette reordering to the image data
-fn apply_palette_reorder(png: &PngImage, remapping: &[usize]) -> Option<PngImage> {
-    let ColorType::Indexed { palette } = &png.ihdr.color_type else {
-        return None;
-    };
-
-    // Check if anything changed
-    if remapping.iter().enumerate().all(|(a, b)| a == *b) {
-        return None;
-    }
-
-    // Construct the palette and byte maps and convert the data
-    let mut new_palette = Vec::new();
-    let mut byte_map = [0; 256];
-    for (i, &v) in remapping.iter().enumerate() {
-        new_palette.push(palette[v]);
-        byte_map[v] = i as u8;
-    }
-    let data = png.data.iter().map(|&b| byte_map[b as usize]).collect();
-
-    Some(PngImage {
-        ihdr: IhdrData {
-            color_type: ColorType::Indexed {
-                palette: new_palette,
-            },
-            ..png.ihdr
-        },
-        data,
-    })
-}
-
-// Find the most popular color on the image edges (the pixels neighboring the filter bytes)
-fn most_popular_edge_color(num_colors: usize, png: &PngImage) -> Option<usize> {
-    let mut counts = [0_u32; 256];
-    for line in png.scan_lines(false) {
-        if let &[first, .., last] = line.data {
-            counts[first as usize] += 1;
-            counts[last as usize] += 1;
-        }
-    }
-    let max = counts
-        .iter()
-        .take(num_colors)
-        .enumerate()
-        .max_by_key(|&(_, v)| v)
-        .unwrap();
-    // Ensure there's a clear winner - return None if multiple colors are tied
-    let max_equal = counts.iter().filter(|&v| v == max.1).count();
-    if max_equal > 1 {
-        return None;
-    }
-    Some(max.0)
-}
-
-// Find the most popular color in the image, along with its count
-fn most_popular_color(num_colors: usize, png: &PngImage) -> (usize, u32) {
-    let mut counts = [0_u32; 256];
-    for &val in &png.data {
-        counts[val as usize] += 1;
-    }
-    counts
-        .iter()
-        .copied()
-        .take(num_colors)
-        .enumerate()
-        .max_by_key(|&(_, v)| v)
-        .unwrap_or_default()
-}
-
-// Put the most popular color first
-fn apply_most_popular_color(png: &PngImage, remapping: &mut [usize]) {
-    let most_popular = most_popular_color(remapping.len(), png);
-    // If the most popular color is less than 15% of the image, don't use it
-    if most_popular.1 < png.data.len() as u32 * 3 / 20 {
-        return;
-    }
-    let first_idx = remapping.iter().position(|&i| i == most_popular.0).unwrap();
-    // If the index is past halfway, reverse the order so as to minimize the change
-    if first_idx >= remapping.len() / 2 {
-        remapping.reverse();
-        remapping.rotate_right(first_idx + 1);
-    } else {
-        remapping.rotate_left(first_idx);
-    }
-}
-
-// Calculate co-occurences matrix
-fn co_occurrence_matrix(num_colors: usize, png: &PngImage) -> Vec<Vec<u32>> {
-    let mut matrix = vec![vec![0_u32; num_colors]; num_colors];
-    let mut prev: Option<ScanLine> = None;
-    let mut prev_val = None;
-    for line in png.scan_lines(false) {
-        for i in 0..line.data.len() {
-            let val = line.data[i] as usize;
-            if val > num_colors {
-                continue;
-            }
-            if let Some(prev_val) = prev_val.replace(val) {
-                matrix[prev_val][val] += 1;
-                matrix[val][prev_val] += 1;
-            }
-            if let Some(prev) = &prev {
-                let prev_val = prev.data[i] as usize;
-                if prev_val > num_colors {
-                    continue;
-                }
-                matrix[prev_val][val] += 1;
-                matrix[val][prev_val] += 1;
-            }
-        }
-        prev = Some(line);
-    }
-    matrix
-}
-
-// Calculate edge list sorted by weight
-fn weighted_edges(matrix: &[Vec<u32>]) -> Vec<(usize, usize)> {
-    let mut edges = Vec::new();
-    for (i, m_row) in matrix.iter().enumerate() {
-        for (j, val) in m_row.iter().enumerate().take(i) {
-            edges.push(((j, i), val));
-        }
-    }
-    edges.sort_by(|(_, w1), (_, w2)| w2.cmp(w1));
-    edges.into_iter().map(|(e, _)| e).collect()
-}
-
-// Apply a greedy index assignment using the modified version of Zeng's techinque from
-// "A note on Zeng's technique for color reindexing of palette-based images" by Pinho et al
-// https://ieeexplore.ieee.org/document/1261987
-// Based on the C implementation in libwebp
-fn mzeng_reindex(num_colors: usize, edges: Vec<(usize, usize)>, matrix: &[Vec<u32>]) -> Vec<usize> {
-    // Initialize the mapping list with the two best indices.
-    let mut remapping = vec![edges[0].0, edges[0].1];
-
-    // Initialize the sums with the first two remappings and find the best one
-    let mut sums = Vec::new();
-    let mut best_sum_pos = 0;
-    let mut best_sum = (0, 0);
-    for (i, m_row) in matrix.iter().enumerate() {
-        if i == remapping[0] || i == remapping[1] {
-            continue;
-        }
-        let sum = (i, m_row[remapping[0]] + m_row[remapping[1]]);
-        if sum.1 > best_sum.1 {
-            best_sum_pos = sums.len();
-            best_sum = sum;
-        }
-        sums.push(sum);
-    }
-
-    while !sums.is_empty() {
-        let best_index = best_sum.0;
-        // Compute delta to know if we need to prepend or append the best index.
-        let mut delta: isize = 0;
-        let n = (num_colors - sums.len()) as isize;
-        for (i, &index) in remapping.iter().enumerate() {
-            delta += (n - 1 - 2 * i as isize) * matrix[best_index][index] as isize;
-        }
-        if delta > 0 {
-            remapping.insert(0, best_index);
-        } else {
-            remapping.push(best_index);
-        }
-        // Remove best_sum from sums.
-        sums.swap_remove(best_sum_pos);
-        if !sums.is_empty() {
-            // Update all the sums and find the best one.
-            best_sum_pos = 0;
-            best_sum = (0, 0);
-            for (i, sum) in sums.iter_mut().enumerate() {
-                sum.1 += matrix[best_index][sum.0];
-                if sum.1 > best_sum.1 {
-                    best_sum_pos = i;
-                    best_sum = *sum;
-                }
-            }
-        }
-    }
-
-    // Return the completed remapping
-    remapping
-}
-
-// Calculate an approximate solution of the Traveling Salesman Problem using the algorithm
-// from "An efficient Re-indexing algorithm for color-mapped images" by Battiato et al
-// https://ieeexplore.ieee.org/document/1344033
-fn battiato_reindex(num_colors: usize, edges: Vec<(usize, usize)>) -> Vec<usize> {
-    let mut chains = Vec::new();
-    // Keep track of the state of each vertex (.0) and it's chain number (.1)
-    // 0 = an unvisited vertex (White)
-    // 1 = an endpoint of a chain (Red)
-    // 2 = part of the middle of a chain (Black)
-    let mut vx = vec![(0, 0); num_colors];
-
-    // Iterate the edges and assemble them into a chain
-    for (i, j) in edges {
-        let vi = vx[i];
-        let vj = vx[j];
-        if vi.0 == 0 && vj.0 == 0 {
-            // Two unvisited vertices - create a new chain
-            vx[i].0 = 1;
-            vx[i].1 = chains.len();
-            vx[j].0 = 1;
-            vx[j].1 = chains.len();
-            chains.push(vec![i, j]);
-        } else if vi.0 == 0 && vj.0 == 1 {
-            // An unvisited vertex connects with an endpoint of an existing chain
-            vx[i].0 = 1;
-            vx[i].1 = vj.1;
-            vx[j].0 = 2;
-            let chain = &mut chains[vj.1];
-            if chain[0] == j {
-                chain.insert(0, i);
-            } else {
-                chain.push(i);
-            }
-        } else if vi.0 == 1 && vj.0 == 0 {
-            // An unvisited vertex connects with an endpoint of an existing chain
-            vx[j].0 = 1;
-            vx[j].1 = vi.1;
-            vx[i].0 = 2;
-            let chain = &mut chains[vi.1];
-            if chain[0] == i {
-                chain.insert(0, j);
-            } else {
-                chain.push(j);
-            }
-        } else if vi.0 == 1 && vj.0 == 1 && vi.1 != vj.1 {
-            // Two endpoints of different chains are connected together
-            vx[i].0 = 2;
-            vx[j].0 = 2;
-            let (a, b) = if vi.1 < vj.1 { (i, j) } else { (j, i) };
-            let ca = vx[a].1;
-            let cb = vx[b].1;
-            let chainb = std::mem::take(&mut chains[cb]);
-            for &v in &chainb {
-                vx[v].1 = ca;
-            }
-            let chaina = &mut chains[ca];
-            if chaina[0] == a && chainb[0] == b {
-                for v in chainb {
-                    chaina.insert(0, v);
-                }
-            } else if chaina[0] == a {
-                chaina.splice(0..0, chainb);
-            } else if chainb[0] == b {
-                chaina.extend(chainb);
-            } else {
-                let pos = chaina.len();
-                for v in chainb {
-                    chaina.insert(pos, v);
-                }
-            }
-        }
-
-        if chains[0].len() == num_colors {
-            break;
-        }
-    }
-
-    // Return the completed chain
-    chains.swap_remove(0)
-}

src/sanity_checks.rs

@@ -1,65 +0,0 @@
-use std::io::Cursor;
-
-use image::{codecs::png::PngDecoder, *};
-use log::{error, warn};
-
-#[cfg(not(feature = "parallel"))]
-use crate::rayon;
-
-/// Validate that the output png data still matches the original image
-pub fn validate_output(output: &[u8], original_data: &[u8]) -> bool {
-    let (old_frames, new_frames) = rayon::join(
-        || load_png_image_from_memory(original_data),
-        || load_png_image_from_memory(output),
-    );
-
-    match (new_frames, old_frames) {
-        (Err(new_err), _) => {
-            error!("Failed to read output image for validation: {}", new_err);
-            false
-        }
-        (_, Err(old_err)) => {
-            // The original image might be invalid if, for example, there is a CRC error,
-            // and we set fix_errors to true. In that case, all we can do is check that the
-            // new image is decodable.
-            warn!("Failed to read input image for validation: {}", old_err);
-            true
-        }
-        (Ok(new_frames), Ok(old_frames)) if new_frames.len() != old_frames.len() => false,
-        (Ok(new_frames), Ok(old_frames)) => {
-            for (a, b) in old_frames.iter().zip(new_frames) {
-                if !images_equal(a, &b) {
-                    return false;
-                }
-            }
-            true
-        }
-    }
-}
-
-/// Loads a PNG image from memory to frames of [RgbaImage]
-fn load_png_image_from_memory(png_data: &[u8]) -> Result<Vec<RgbaImage>, image::ImageError> {
-    let decoder = PngDecoder::new(Cursor::new(png_data))?;
-    if decoder.is_apng()? {
-        decoder
-            .apng()?
-            .into_frames()
-            .map(|f| f.map(image::Frame::into_buffer))
-            .collect()
-    } else {
-        DynamicImage::from_decoder(decoder).map(|i| vec![i.into_rgba8()])
-    }
-}
-
-/// Compares images pixel by pixel for equivalent content
-fn images_equal(old_png: &RgbaImage, new_png: &RgbaImage) -> bool {
-    let a = old_png.pixels().filter(|x| {
-        let p = x.channels();
-        !(p.len() == 4 && p[3] == 0)
-    });
-    let b = new_png.pixels().filter(|x| {
-        let p = x.channels();
-        !(p.len() == 4 && p[3] == 0)
-    });
-    a.eq(b)
-}

tests/alpha.rs

@@ -1,346 +0,0 @@
-use std::{
-    fs::remove_file,
-    path::{Path, PathBuf},
-};
-
-use oxipng::{internal_tests::*, *};
-
-const GRAYSCALE_ALPHA: u8 = 4;
-const RGBA: u8 = 6;
-
-fn get_opts(input: &Path) -> (OutFile, oxipng::Options) {
-    let options = oxipng::Options {
-        force: true,
-        optimize_alpha: true,
-        ..Default::default()
-    };
-    (OutFile::from_path(input.with_extension("out.png")), options)
-}
-
-fn test_it_converts(
-    input: &str,
-    filter: FilterStrategy,
-    color_type_in: u8,
-    bit_depth_in: BitDepth,
-    color_type_out: u8,
-    bit_depth_out: BitDepth,
-) {
-    let input = PathBuf::from(input);
-
-    let (output, mut opts) = get_opts(&input);
-    let png = PngData::new(&input, &opts).unwrap();
-    opts.filters = indexset! {filter};
-    assert_eq!(png.raw.ihdr.color_type.png_header_code(), color_type_in);
-    assert_eq!(png.raw.ihdr.bit_depth, bit_depth_in);
-
-    match oxipng::optimize(&InFile::Path(input), &output, &opts) {
-        Ok(_) => (),
-        Err(x) => panic!("{}", x),
-    }
-    let output = output.path().unwrap();
-    assert!(output.exists());
-
-    let png = match PngData::new(output, &opts) {
-        Ok(x) => x,
-        Err(x) => {
-            remove_file(output).ok();
-            panic!("{}", x)
-        }
-    };
-
-    assert_eq!(png.raw.ihdr.color_type.png_header_code(), color_type_out);
-    assert_eq!(png.raw.ihdr.bit_depth, bit_depth_out);
-    if let ColorType::Indexed { palette } = &png.raw.ihdr.color_type {
-        assert!(palette.len() <= 1 << (png.raw.ihdr.bit_depth as u8));
-    }
-
-    remove_file(output).ok();
-}
-
-#[test]
-fn alpha_filter_0_for_rgba_16() {
-    test_it_converts(
-        "tests/files/filter_0_for_rgba_16.png",
-        FilterStrategy::NONE,
-        RGBA,
-        BitDepth::Sixteen,
-        RGBA,
-        BitDepth::Sixteen,
-    );
-}
-
-#[test]
-fn alpha_filter_1_for_rgba_16() {
-    test_it_converts(
-        "tests/files/filter_1_for_rgba_16.png",
-        FilterStrategy::SUB,
-        RGBA,
-        BitDepth::Sixteen,
-        RGBA,
-        BitDepth::Sixteen,
-    );
-}
-
-#[test]
-fn alpha_filter_2_for_rgba_16() {
-    test_it_converts(
-        "tests/files/filter_2_for_rgba_16.png",
-        FilterStrategy::UP,
-        RGBA,
-        BitDepth::Sixteen,
-        RGBA,
-        BitDepth::Sixteen,
-    );
-}
-
-#[test]
-fn alpha_filter_3_for_rgba_16() {
-    test_it_converts(
-        "tests/files/filter_3_for_rgba_16.png",
-        FilterStrategy::AVERAGE,
-        RGBA,
-        BitDepth::Sixteen,
-        RGBA,
-        BitDepth::Sixteen,
-    );
-}
-
-#[test]
-fn alpha_filter_4_for_rgba_16() {
-    test_it_converts(
-        "tests/files/filter_4_for_rgba_16.png",
-        FilterStrategy::PAETH,
-        RGBA,
-        BitDepth::Sixteen,
-        RGBA,
-        BitDepth::Sixteen,
-    );
-}
-
-#[test]
-fn alpha_filter_5_for_rgba_16() {
-    test_it_converts(
-        "tests/files/filter_5_for_rgba_16.png",
-        FilterStrategy::MinSum,
-        RGBA,
-        BitDepth::Sixteen,
-        RGBA,
-        BitDepth::Sixteen,
-    );
-}
-
-#[test]
-fn alpha_filter_0_for_rgba_8() {
-    test_it_converts(
-        "tests/files/filter_0_for_rgba_8.png",
-        FilterStrategy::NONE,
-        RGBA,
-        BitDepth::Eight,
-        RGBA,
-        BitDepth::Eight,
-    );
-}
-
-#[test]
-fn alpha_filter_1_for_rgba_8() {
-    test_it_converts(
-        "tests/files/filter_1_for_rgba_8.png",
-        FilterStrategy::SUB,
-        RGBA,
-        BitDepth::Eight,
-        RGBA,
-        BitDepth::Eight,
-    );
-}
-
-#[test]
-fn alpha_filter_2_for_rgba_8() {
-    test_it_converts(
-        "tests/files/filter_2_for_rgba_8.png",
-        FilterStrategy::UP,
-        RGBA,
-        BitDepth::Eight,
-        RGBA,
-        BitDepth::Eight,
-    );
-}
-
-#[test]
-fn alpha_filter_3_for_rgba_8() {
-    test_it_converts(
-        "tests/files/filter_3_for_rgba_8.png",
-        FilterStrategy::AVERAGE,
-        RGBA,
-        BitDepth::Eight,
-        RGBA,
-        BitDepth::Eight,
-    );
-}
-
-#[test]
-fn alpha_filter_4_for_rgba_8() {
-    test_it_converts(
-        "tests/files/filter_4_for_rgba_8.png",
-        FilterStrategy::PAETH,
-        RGBA,
-        BitDepth::Eight,
-        RGBA,
-        BitDepth::Eight,
-    );
-}
-
-#[test]
-fn alpha_filter_5_for_rgba_8() {
-    test_it_converts(
-        "tests/files/filter_5_for_rgba_8.png",
-        FilterStrategy::MinSum,
-        RGBA,
-        BitDepth::Eight,
-        RGBA,
-        BitDepth::Eight,
-    );
-}
-
-#[test]
-fn alpha_filter_0_for_grayscale_alpha_16() {
-    test_it_converts(
-        "tests/files/filter_0_for_grayscale_alpha_16.png",
-        FilterStrategy::NONE,
-        GRAYSCALE_ALPHA,
-        BitDepth::Sixteen,
-        GRAYSCALE_ALPHA,
-        BitDepth::Sixteen,
-    );
-}
-
-#[test]
-fn alpha_filter_1_for_grayscale_alpha_16() {
-    test_it_converts(
-        "tests/files/filter_1_for_grayscale_alpha_16.png",
-        FilterStrategy::SUB,
-        GRAYSCALE_ALPHA,
-        BitDepth::Sixteen,
-        GRAYSCALE_ALPHA,
-        BitDepth::Sixteen,
-    );
-}
-
-#[test]
-fn alpha_filter_2_for_grayscale_alpha_16() {
-    test_it_converts(
-        "tests/files/filter_2_for_grayscale_alpha_16.png",
-        FilterStrategy::UP,
-        GRAYSCALE_ALPHA,
-        BitDepth::Sixteen,
-        GRAYSCALE_ALPHA,
-        BitDepth::Sixteen,
-    );
-}
-
-#[test]
-fn alpha_filter_3_for_grayscale_alpha_16() {
-    test_it_converts(
-        "tests/files/filter_3_for_grayscale_alpha_16.png",
-        FilterStrategy::AVERAGE,
-        GRAYSCALE_ALPHA,
-        BitDepth::Sixteen,
-        GRAYSCALE_ALPHA,
-        BitDepth::Sixteen,
-    );
-}
-
-#[test]
-fn alpha_filter_4_for_grayscale_alpha_16() {
-    test_it_converts(
-        "tests/files/filter_4_for_grayscale_alpha_16.png",
-        FilterStrategy::PAETH,
-        GRAYSCALE_ALPHA,
-        BitDepth::Sixteen,
-        GRAYSCALE_ALPHA,
-        BitDepth::Sixteen,
-    );
-}
-
-#[test]
-fn alpha_filter_5_for_grayscale_alpha_16() {
-    test_it_converts(
-        "tests/files/filter_5_for_grayscale_alpha_16.png",
-        FilterStrategy::MinSum,
-        GRAYSCALE_ALPHA,
-        BitDepth::Sixteen,
-        GRAYSCALE_ALPHA,
-        BitDepth::Sixteen,
-    );
-}
-
-#[test]
-fn alpha_filter_0_for_grayscale_alpha_8() {
-    test_it_converts(
-        "tests/files/filter_0_for_grayscale_alpha_8.png",
-        FilterStrategy::NONE,
-        GRAYSCALE_ALPHA,
-        BitDepth::Eight,
-        GRAYSCALE_ALPHA,
-        BitDepth::Eight,
-    );
-}
-
-#[test]
-fn alpha_filter_1_for_grayscale_alpha_8() {
-    test_it_converts(
-        "tests/files/filter_1_for_grayscale_alpha_8.png",
-        FilterStrategy::SUB,
-        GRAYSCALE_ALPHA,
-        BitDepth::Eight,
-        GRAYSCALE_ALPHA,
-        BitDepth::Eight,
-    );
-}
-
-#[test]
-fn alpha_filter_2_for_grayscale_alpha_8() {
-    test_it_converts(
-        "tests/files/filter_2_for_grayscale_alpha_8.png",
-        FilterStrategy::UP,
-        GRAYSCALE_ALPHA,
-        BitDepth::Eight,
-        GRAYSCALE_ALPHA,
-        BitDepth::Eight,
-    );
-}
-
-#[test]
-fn alpha_filter_3_for_grayscale_alpha_8() {
-    test_it_converts(
-        "tests/files/filter_3_for_grayscale_alpha_8.png",
-        FilterStrategy::AVERAGE,
-        GRAYSCALE_ALPHA,
-        BitDepth::Eight,
-        GRAYSCALE_ALPHA,
-        BitDepth::Eight,
-    );
-}
-
-#[test]
-fn alpha_filter_4_for_grayscale_alpha_8() {
-    test_it_converts(
-        "tests/files/filter_4_for_grayscale_alpha_8.png",
-        FilterStrategy::PAETH,
-        GRAYSCALE_ALPHA,
-        BitDepth::Eight,
-        GRAYSCALE_ALPHA,
-        BitDepth::Eight,
-    );
-}
-
-#[test]
-fn alpha_filter_5_for_grayscale_alpha_8() {
-    test_it_converts(
-        "tests/files/filter_5_for_grayscale_alpha_8.png",
-        FilterStrategy::MinSum,
-        GRAYSCALE_ALPHA,
-        BitDepth::Eight,
-        GRAYSCALE_ALPHA,
-        BitDepth::Eight,
-    );
-}