chore(deps): bump the rust-dependencies group with 2 updates (#818)

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.cargo/config.toml

@@ -1,9 +1,2 @@
-# Remove this if targeting AArch64 from an AArch64 Linux box
+[alias]
-[target.'cfg(all(target_os = "linux", target_arch = "aarch64"))']
+xtask = "run --manifest-path xtask/Cargo.toml --"
-runner = 'qemu-aarch64'
-
-[target.aarch64-unknown-linux-gnu]
-linker = 'aarch64-linux-gnu-gcc'
-
-[target.aarch64-unknown-linux-musl]
-linker = 'aarch64-linux-musl-gcc'

.dockerignore

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

.github/dependabot.yml

@@ -1,6 +1,24 @@
 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: monthly
+      interval: "weekly"

.github/workflows/deploy.yml

@@ -3,7 +3,12 @@ name: deploy
 on:
   push:
     tags:
-      - 'v*.*.*'
+      - 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
@@ -20,6 +25,10 @@ jobs:
     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
@@ -33,18 +42,32 @@ jobs:
 
     steps:
       - name: Checkout source
-        uses: actions/checkout@v4
+        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=$(cargo metadata --format-version 1 --no-deps | jq -r '.packages[] | select(.name == "oxipng").version')"
+        run: >
-          >> "$GITHUB_OUTPUT"
+          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@v3
+        uses: dawidd6/action-download-artifact@v21
         with:
           workflow: oxipng.yml
-          commit: ${{ env.GITHUB_SHA }}
+          commit: ${{ github.sha }}
           name: Oxipng binary (${{ matrix.target }})
           path: target
 
@@ -71,12 +94,12 @@ jobs:
               # so make the binary world-executable to meet user
               # expectations set by preceding releases.
               # Related issue:
-              # https://github.com/shssoichiro/oxipng/issues/575
+              # https://github.com/oxipng/oxipng/issues/575
               chmod ugo+x "$ARCHIVE_NAME"/oxipng
               tar -vczf "${ARCHIVE_NAME}.tar.gz" "$ARCHIVE_NAME"/*;;
           esac
 
-      - name: Install QEMU and AArch64 cross compiler
+      - name: Install AArch64 libc components
         if: matrix.target == 'aarch64-unknown-linux-gnu'
         run: |
           sudo apt-get -yq update
@@ -85,20 +108,27 @@ jobs:
           # properly
           sudo apt-get -yq install libc6-arm64-cross libgcc-s1-arm64-cross
 
-      - name: Build deb archives
+      - 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"
-          mv target/debug/assets "target/${{ matrix.target }}/release"
-          cargo install --locked cargo-deb
           cargo deb --target "${{ 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@v2
+        uses: softprops/action-gh-release@v3
         with:
           name: v${{ steps.oxipngMeta.outputs.version }}
           body_path: RELEASE_NOTES.txt

.github/workflows/docker.yml

@@ -0,0 +1,60 @@
+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

@@ -8,6 +8,11 @@ on:
       - 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
@@ -33,94 +38,83 @@ jobs:
 
         include:
           - target: x86_64-unknown-linux-gnu
-            os: ubuntu-22.04
+            os: ubuntu-24.04
             target-apt-arch: amd64
           - target: x86_64-unknown-linux-musl
-            os: ubuntu-22.04
+            os: ubuntu-24.04
             target-apt-arch: amd64
           - target: aarch64-unknown-linux-gnu
-            os: ubuntu-22.04
+            os: ubuntu-24.04-arm
             target-apt-arch: arm64
           - target: aarch64-unknown-linux-musl
-            os: ubuntu-22.04
+            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-12
+            os: macos-15
           - target: aarch64-apple-darwin
-            os: macos-14 # ARM64 runner
+            os: macos-15
 
     env:
       CARGO_BUILD_TARGET: ${{ matrix.target }}
-      RUSTFLAGS: -Zlocation-detail=none
 
     steps:
       - name: Checkout source
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           persist-credentials: false
 
-      - name: Set up Ubuntu multiarch
-        if: startsWith(matrix.os, 'ubuntu') && matrix.target-apt-arch != 'amd64'
-        run: |
-          readonly DISTRO_CODENAME=jammy
-          sudo dpkg --add-architecture "${{ matrix.target-apt-arch }}"
-          sudo sed -i "s/^deb http/deb [arch=$(dpkg-architecture -q DEB_HOST_ARCH)] http/" /etc/apt/sources.list
-          sudo sed -i "s/^deb mirror/deb [arch=$(dpkg-architecture -q DEB_HOST_ARCH)] mirror/" /etc/apt/sources.list
-          for suite in '' '-updates' '-backports' '-security'; do
-            echo "deb [arch=${{ matrix.target-apt-arch }}] http://ports.ubuntu.com/ $DISTRO_CODENAME$suite main universe multiverse" | \
-            sudo tee -a /etc/apt/sources.list >/dev/null
-          done
-
       - 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 QEMU and AArch64 cross compiler
-        if: startsWith(matrix.target, 'aarch64-unknown-linux')
-        run: |
-          sudo apt-get -yq update
-          # libc6 must be present to run executables dynamically linked
-          # against glibc for the target architecture
-          sudo apt-get -yq install qemu-user gcc-aarch64-linux-gnu libc6:arm64
-
-      - name: Cache Cargo artifacts
-        uses: Swatinem/rust-cache@v2
-
       - name: Install Rust toolchain
-        uses: dtolnay/rust-toolchain@v1
+        uses: actions-rust-lang/setup-rust-toolchain@v1
         with:
           toolchain: nightly
-          targets: ${{ env.CARGO_BUILD_TARGET }}
+          target: ${{ env.CARGO_BUILD_TARGET }}
-          components: clippy, rustfmt
+          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 (no default features)
+      - name: Run Clippy for all feature combinations
         if: matrix.target == 'x86_64-unknown-linux-gnu'
-        uses: giraffate/clippy-action@v1
+        run: >
-        with:
+          set -o pipefail;
-          clippy_flags: --no-deps --all-targets --no-default-features -- -D warnings
+          cargo hack clippy --no-deps --all-targets --feature-powerset \
-          reporter: github-check
+            --exclude-features sanity-checks,system-libdeflate \
-          fail_on_error: true
+            --message-format=json -- -D warnings \
-
+          | clippy-sarif
-      - name: Run Clippy (all features)
+          | tee clippy-results.sarif
-        if: matrix.target == 'x86_64-unknown-linux-gnu'
+          | sarif-fmt
-        uses: giraffate/clippy-action@v1
-        with:
-          clippy_flags: --no-deps --all-targets --all-features -- -D warnings
-          reporter: github-check
-          fail_on_error: true
 
       - name: Run tests
         run: |
@@ -135,16 +129,26 @@ jobs:
         run: cargo doc --release --no-deps
 
       - name: Build CLI binary
-        run: cargo build --release
+        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@v4
+        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
 
@@ -156,15 +160,16 @@ jobs:
 
     steps:
       - name: Checkout source
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           persist-credentials: false
 
-      - name: Cache Cargo artifacts
-        uses: Swatinem/rust-cache@v2
-
       - name: Install MSRV Rust toolchain
-        uses: dtolnay/rust-toolchain@1.74.0
+        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

.gitignore

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

CHANGELOG.md

@@ -1,3 +1,65 @@
+## 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.
@@ -137,51 +199,51 @@
 ### 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/shssoichiro/oxipng/pull/202))
+- [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/shssoichiro/oxipng/pull/211/files#diff-b4aea3e418ccdb71239b96952d9cddb6L217), [#212](https://github.com/shssoichiro/oxipng/pull/212/files#diff-b4aea3e418ccdb71239b96952d9cddb6L134))
+- [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/shssoichiro/oxipng/pull/210/files))
+- [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/shssoichiro/oxipng/pull/203))
+- [Feature] Add libdeflater as an option ([#203](https://github.com/oxipng/oxipng/pull/203))
-- [Feature] Use standard `log` library ([#218](https://github.com/shssoichiro/oxipng/pull/218))
+- [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/shssoichiro/oxipng/pull/224))
+- [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/shssoichiro/oxipng/pull/224))
+  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/shssoichiro/oxipng/pull/199))
+- [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/shssoichiro/oxipng/pull/181))
+- Allow disabling all alpha optimizations ([#181](https://github.com/oxipng/oxipng/pull/181))
-- Fix interlacing issues on tiny images ([#182](https://github.com/shssoichiro/oxipng/pull/182))
+- Fix interlacing issues on tiny images ([#182](https://github.com/oxipng/oxipng/pull/182))
-- Reduce memory usage in filtering ([#191](https://github.com/shssoichiro/oxipng/pull/191))
+- Reduce memory usage in filtering ([#191](https://github.com/oxipng/oxipng/pull/191))
-- Implement palette sorting to improve compression ([#193](https://github.com/shssoichiro/oxipng/pull/193))
+- Implement palette sorting to improve compression ([#193](https://github.com/oxipng/oxipng/pull/193))
-- Disable alpha optimizations by default ([#187](https://github.com/shssoichiro/oxipng/pull/187))
+- Disable alpha optimizations by default ([#187](https://github.com/oxipng/oxipng/pull/187))
-- Add support for WASM ([#194](https://github.com/shssoichiro/oxipng/pull/194))
+- 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/shssoichiro/oxipng/pull/171))
+- Fix grayscale bit-depth reduction ([#171](https://github.com/oxipng/oxipng/pull/171))
-- Fix typos and incorrect log message ([#172](https://github.com/shssoichiro/oxipng/pull/172))
+- Fix typos and incorrect log message ([#172](https://github.com/oxipng/oxipng/pull/172))
-- Make metadata order deterministic ([#174](https://github.com/shssoichiro/oxipng/pull/174))
+- Make metadata order deterministic ([#174](https://github.com/oxipng/oxipng/pull/174))
-- Fix 32-bit builds ([#176](https://github.com/shssoichiro/oxipng/pull/176))
+- Fix 32-bit builds ([#176](https://github.com/oxipng/oxipng/pull/176))
-- Enable LTO in release builds ([#177](https://github.com/shssoichiro/oxipng/pull/177))
+- Enable LTO in release builds ([#177](https://github.com/oxipng/oxipng/pull/177))
-- Use deterministic compression strategy ([#179](https://github.com/shssoichiro/oxipng/pull/179))
+- 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/shssoichiro/oxipng/pull/175))
+- 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/shssoichiro/oxipng/pull/180))
+- 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/shssoichiro/oxipng/pull/167)) ([#168](https://github.com/shssoichiro/oxipng/pull/168))
+- 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/shssoichiro/oxipng/pull/154)) ([#158](https://github.com/shssoichiro/oxipng/pull/158)) ([#160](https://github.com/shssoichiro/oxipng/pull/160)) ([#161](https://github.com/shssoichiro/oxipng/pull/161)) ([#162](https://github.com/shssoichiro/oxipng/pull/162)) ([#163](https://github.com/shssoichiro/oxipng/pull/163))
+- 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
@@ -190,24 +252,24 @@
 
 ### Version 2.1.8
 
-- Fix non-standard sBIT headers in other code locations ([#153](https://github.com/shssoichiro/oxipng/issues/153))
+- 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/shssoichiro/oxipng/pull/150))
+- 80x faster palette reduction ([#150](https://github.com/oxipng/oxipng/pull/150))
-- Optimize RGB to palette conversion ([#148](https://github.com/shssoichiro/oxipng/pull/148))
+- Optimize RGB to palette conversion ([#148](https://github.com/oxipng/oxipng/pull/148))
-- Various microoptimizations ([#146](https://github.com/shssoichiro/oxipng/pull/146))
+- Various microoptimizations ([#146](https://github.com/oxipng/oxipng/pull/146))
-- Introduce third-party safe wrapper around cloudflare-zlib ([#149](https://github.com/shssoichiro/oxipng/pull/149))
+- 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/shssoichiro/oxipng/pull/143))
+- Identify and drop useless sRGB profiles ([#143](https://github.com/oxipng/oxipng/pull/143))
-- Alpha heuristic improvements ([#144](https://github.com/shssoichiro/oxipng/pull/144))
+- 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
 
@@ -220,22 +282,22 @@
 
 ### 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] 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
 
 ### 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
 
@@ -272,12 +334,12 @@
 
 ### 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
 
 ### 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.
   - [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.
@@ -304,30 +366,30 @@
 
 ### 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
-- 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
-- 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 `image` to 0.17
 - [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
-- 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
 
@@ -343,14 +405,14 @@
   trials for optimizing the alpha channel, using the previously mentioned fast heuristic.
   This option will make optimization of images with transparency somewhat slower,
   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
 - 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
 
@@ -368,18 +430,18 @@
 
 ### 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 `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
 
 ### Version 0.14.4
@@ -413,14 +475,14 @@
 
 ### 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
 - [SMEVER_MAJOR] Bump minimum required rustc version to 1.12.0
 
 ### Version 0.12.0
 
 - 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.
 
 ### Version 0.11.0
@@ -445,7 +507,7 @@
 
 ### 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
 
@@ -461,7 +523,7 @@
 - Minor compression improvement on interlaced images
 - Performance optimizations
 - [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
 
@@ -472,47 +534,47 @@
 
 ### 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
-- 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
-- [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
 - Fix issue where interlaced images incorrectly applied filters on the first line of a pass
 
 ### Version 0.3.0
 
 - 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
 
 ### Version 0.2.2
 
 - 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
-- 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`
-- 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
-- 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_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
 

Cargo.lock

@@ -1,78 +1,74 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-version = 3
+version = 4
 
 [[package]]
-name = "adler"
+name = "adler2"
-version = "1.0.2"
+version = "2.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f26201604c87b1e01bd3d98f8d5d9a8fcbb815e8cedb41ffccbeb4bf593a35fe"
+checksum = "320119579fcad9c21884f5c4861d16174d0e06250625266f50fe6898340abefa"
 
 [[package]]
 name = "anstream"
-version = "0.6.13"
+version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d96bd03f33fe50a863e394ee9718a706f988b9079b20c3784fb726e7678b62fb"
+checksum = "824a212faf96e9acacdbd09febd34438f8f711fb84e09a8916013cd7815ca28d"
 dependencies = [
  "anstyle",
  "anstyle-parse",
  "anstyle-query",
  "anstyle-wincon",
  "colorchoice",
+ "is_terminal_polyfill",
  "utf8parse",
 ]
 
 [[package]]
 name = "anstyle"
-version = "1.0.6"
+version = "1.0.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8901269c6307e8d93993578286ac0edf7f195079ffff5ebdeea6a59ffb7e36bc"
+checksum = "940b3a0ca603d1eade50a4846a2afffd5ef57a9feac2c0e2ec2e14f9ead76000"
 
 [[package]]
 name = "anstyle-parse"
-version = "0.2.3"
+version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c75ac65da39e5fe5ab759307499ddad880d724eed2f6ce5b5e8a26f4f387928c"
+checksum = "52ce7f38b242319f7cabaa6813055467063ecdc9d355bbb4ce0c68908cd8130e"
 dependencies = [
  "utf8parse",
 ]
 
 [[package]]
 name = "anstyle-query"
-version = "1.0.2"
+version = "1.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e28923312444cdd728e4738b3f9c9cac739500909bb3d3c94b43551b16517648"
+checksum = "40c48f72fd53cd289104fc64099abca73db4166ad86ea0b4341abe65af83dadc"
 dependencies = [
- "windows-sys 0.52.0",
+ "windows-sys",
 ]
 
 [[package]]
 name = "anstyle-wincon"
-version = "3.0.2"
+version = "3.0.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1cd54b81ec8d6180e24654d0b371ad22fc3dd083b6ff8ba325b72e00c87660a7"
+checksum = "291e6a250ff86cd4a820112fb8898808a366d8f9f58ce16d1f538353ad55747d"
 dependencies = [
  "anstyle",
- "windows-sys 0.52.0",
+ "once_cell_polyfill",
+ "windows-sys",
 ]
 
 [[package]]
 name = "autocfg"
-version = "1.2.0"
+version = "1.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f1fdabc7756949593fe60f30ec81974b613357de856987752631dea1e3394c80"
+checksum = "c08606f8c3cbf4ce6ec8e28fb0014a2c086708fe954eaa885384a6165172e7e8"
 
 [[package]]
 name = "bitflags"
-version = "1.3.2"
+version = "2.11.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
+checksum = "c4512299f36f043ab09a583e57bceb5a5aab7a73db1805848e8fef3c9e8c78b3"
-
-[[package]]
-name = "bitflags"
-version = "2.5.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cf4b9d6a944f767f8e5e0db018570623c85f3d925ac718db4e06d0187adb21c1"
 
 [[package]]
 name = "bitvec"
@@ -87,43 +83,53 @@ dependencies = [
 ]
 
 [[package]]
-name = "bytemuck"
+name = "bumpalo"
-version = "1.15.0"
+version = "3.20.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5d6d68c57235a3a081186990eca2867354726650f42f7516ca50c28d6281fd15"
+checksum = "5d20789868f4b01b2f2caec9f5c4e0213b41e3e5702a50157d699ae31ced2fcb"
 
 [[package]]
-name = "byteorder"
+name = "bytemuck"
-version = "1.5.0"
+version = "1.25.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1fd0f2584146f6f2ef48085050886acf353beff7305ebd1ae69500e27c67f64b"
+checksum = "c8efb64bd706a16a1bdde310ae86b351e4d21550d98d056f22f8a7f7a2183fec"
+
+[[package]]
+name = "byteorder-lite"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8f1fe948ff07f4bd06c30984e69f5b4899c516a3ef74f34df92a2df2ab535495"
 
 [[package]]
 name = "cc"
-version = "1.0.92"
+version = "1.2.60"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2678b2e3449475e95b0aa6f9b506a28e61b3dc8996592b983695e8ebb58a8b41"
+checksum = "43c5703da9466b66a946814e1adf53ea2c90f10063b86290cc9eb67ce3478a20"
+dependencies = [
+ "find-msvc-tools",
+ "shlex",
+]
 
 [[package]]
 name = "cfg-if"
-version = "1.0.0"
+version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
 
 [[package]]
 name = "clap"
-version = "4.5.4"
+version = "4.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "90bc066a67923782aa8515dbaea16946c5bcc5addbd668bb80af688e53e548a0"
+checksum = "1ddb117e43bbf7dacf0a4190fef4d345b9bad68dfc649cb349e7d17d28428e51"
 dependencies = [
  "clap_builder",
 ]
 
 [[package]]
 name = "clap_builder"
-version = "4.5.2"
+version = "4.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ae129e2e766ae0ec03484e609954119f123cc1fe650337e155d03b022f24f7b4"
+checksum = "714a53001bf66416adb0e2ef5ac857140e7dc3a0c48fb28b2f10762fc4b5069f"
 dependencies = [
  "anstream",
  "anstyle",
@@ -134,49 +140,30 @@ dependencies = [
 
 [[package]]
 name = "clap_lex"
-version = "0.7.0"
+version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "98cc8fbded0c607b7ba9dd60cd98df59af97e84d24e49c8557331cfc26d301ce"
+checksum = "c8d4a3bb8b1e0c1050499d1815f5ab16d04f0959b233085fb31653fbfc9d98f9"
-
-[[package]]
-name = "clap_mangen"
-version = "0.2.20"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e1dd95b5ebb5c1c54581dd6346f3ed6a79a3eef95dd372fc2ac13d535535300e"
-dependencies = [
- "clap",
- "roff",
-]
 
 [[package]]
 name = "colorchoice"
-version = "1.0.0"
+version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "acbf1af155f9b9ef647e42cdc158db4b64a1b61f743629225fde6f3e0be2a7c7"
+checksum = "1d07550c9036bf2ae0c684c4297d503f838287c83c53686d05370d0e139ae570"
 
 [[package]]
 name = "crc32fast"
-version = "1.4.0"
+version = "1.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b3855a8a784b474f333699ef2bbca9db2c4a1f6d9088a90a2d25b1eb53111eaa"
+checksum = "9481c1c90cbf2ac953f07c8d4a58aa3945c425b7185c9154d67a65e4230da511"
 dependencies = [
  "cfg-if",
 ]
 
-[[package]]
-name = "crossbeam-channel"
-version = "0.5.12"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ab3db02a9c5b5121e1e42fbdb1aeb65f5e02624cc58c43f2884c6ccac0b82f95"
-dependencies = [
- "crossbeam-utils",
-]
-
 [[package]]
 name = "crossbeam-deque"
-version = "0.8.5"
+version = "0.8.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "613f8cc01fe9cf1a3eb3d7f488fd2fa8388403e97039e2f73692932e291a770d"
+checksum = "9dd111b7b7f7d55b72c0a6ae361660ee5853c9af73f70c3c2ef6858b950e2e51"
 dependencies = [
  "crossbeam-epoch",
  "crossbeam-utils",
@@ -193,30 +180,30 @@ dependencies = [
 
 [[package]]
 name = "crossbeam-utils"
-version = "0.8.19"
+version = "0.8.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "248e3bacc7dc6baa3b21e405ee045c3047101a49145e7e9eca583ab4c2ca5345"
+checksum = "d0a5c400df2834b80a4c3327b3aad3a4c4cd4de0629063962b03235697506a28"
 
 [[package]]
 name = "either"
-version = "1.10.0"
+version = "1.15.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "11157ac094ffbdde99aa67b23417ebdd801842852b500e395a45a9c0aac03e4a"
+checksum = "48c757948c5ede0e46177b7add2e67155f70e33c07fea8284df6576da70b3719"
 
 [[package]]
 name = "env_filter"
-version = "0.1.0"
+version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a009aa4810eb158359dda09d0c87378e4bbb89b5a801f016885a4707ba24f7ea"
+checksum = "32e90c2accc4b07a8456ea0debdc2e7587bdd890680d71173a15d4ae604f6eef"
 dependencies = [
  "log",
 ]
 
 [[package]]
 name = "env_logger"
-version = "0.11.3"
+version = "0.11.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "38b35839ba51819680ba087cd351788c9a3c476841207e0b8cee0b04722343b9"
+checksum = "0621c04f2196ac3f488dd583365b9c09be011a4ab8b9f37248ffcc8f6198b56a"
 dependencies = [
  "anstream",
  "anstyle",
@@ -226,46 +213,40 @@ dependencies = [
 
 [[package]]
 name = "equivalent"
-version = "1.0.1"
+version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5443807d6dff69373d433ab9ef5378ad8df50ca6298caf15de6e52e24aaf54d5"
+checksum = "877a4ace8713b0bcf2a4e7eec82529c029f1d0619886d18145fea96c3ffe5c0f"
 
 [[package]]
 name = "errno"
-version = "0.3.8"
+version = "0.3.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a258e46cdc063eb8519c00b9fc845fc47bcfca4130e2f08e88665ceda8474245"
+checksum = "39cab71617ae0d63f51a36d69f866391735b51691dbda63cf6f96d042b63efeb"
 dependencies = [
  "libc",
- "windows-sys 0.52.0",
+ "windows-sys",
 ]
 
 [[package]]
 name = "fdeflate"
-version = "0.3.4"
+version = "0.3.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4f9bfee30e4dedf0ab8b422f03af778d9612b63f502710fc500a334ebe2de645"
+checksum = "1e6853b52649d4ac5c0bd02320cddc5ba956bdb407c4b75a2c6b75bf51500f8c"
 dependencies = [
  "simd-adler32",
 ]
 
 [[package]]
-name = "filetime"
+name = "find-msvc-tools"
-version = "0.2.23"
+version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1ee447700ac8aa0b2f2bd7bc4462ad686ba06baa6727ac149a2d6277f0d240fd"
+checksum = "5baebc0774151f905a1a2cc41989300b1e6fbb29aff0ceffa1064fdd3088d582"
-dependencies = [
- "cfg-if",
- "libc",
- "redox_syscall",
- "windows-sys 0.52.0",
-]
 
 [[package]]
 name = "flate2"
-version = "1.0.28"
+version = "1.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "46303f565772937ffe1d394a4fac6f411c6013172fadde9dcdb1e147a086940e"
+checksum = "843fba2746e448b37e26a819579957415c8cef339bf08564fe8b7ddbd959573c"
 dependencies = [
  "crc32fast",
  "miniz_oxide",
@@ -279,33 +260,34 @@ checksum = "e6d5a32815ae3f33302d95fdcb2ce17862f8c65363dcfd29360480ba1001fc9c"
 
 [[package]]
 name = "glob"
-version = "0.3.1"
+version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d2fabcfbdc87f4758337ca535fb41a6d701b65693ce38287d856d1674551ec9b"
+checksum = "0cc23270f6e1808e30a928bdc84dea0b9b4136a8bc82338574f23baf47bbd280"
 
 [[package]]
 name = "hashbrown"
-version = "0.14.3"
+version = "0.17.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "290f1a1d9242c78d09ce40a5e87e7554ee637af1351968159f4952f028f75604"
+checksum = "4f467dd6dccf739c208452f8014c75c18bb8301b050ad1cfb27153803edb0f51"
 
 [[package]]
 name = "image"
-version = "0.25.1"
+version = "0.25.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fd54d660e773627692c524beaad361aca785a4f9f5730ce91f42aabe5bce3d11"
+checksum = "e6506c6c10786659413faa717ceebcb8f70731c0a60cbae39795fdf114519c1a"
 dependencies = [
  "bytemuck",
- "byteorder",
+ "byteorder-lite",
+ "moxcms",
  "num-traits",
  "png",
 ]
 
 [[package]]
 name = "indexmap"
-version = "2.2.6"
+version = "2.14.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "168fb715dda47215e360912c096649d23d58bf392ac62f73919e831745e40f26"
+checksum = "d466e9454f08e4a911e14806c24e16fba1b4c121d1ea474396f396069cf949d9"
 dependencies = [
  "equivalent",
  "hashbrown",
@@ -313,95 +295,164 @@ dependencies = [
 ]
 
 [[package]]
-name = "libc"
+name = "is_terminal_polyfill"
-version = "0.2.153"
+version = "1.70.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9c198f91728a82281a64e1f4f9eeb25d82cb32a5de251c6bd1b5154d63a8e7bd"
+checksum = "a6cb138bb79a146c1bd460005623e142ef0181e3d0219cb493e02f7d08a35695"
+
+[[package]]
+name = "itoa"
+version = "1.0.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8f42a60cbdf9a97f5d2305f08a87dc4e09308d1276d28c869c684d7777685682"
+
+[[package]]
+name = "libc"
+version = "0.2.185"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "52ff2c0fe9bc6cb6b14a0592c2ff4fa9ceb83eea9db979b0487cd054946a2b8f"
 
 [[package]]
 name = "libdeflate-sys"
-version = "1.20.0"
+version = "1.25.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "669ea17f9257bcb48c09c7ee4bef3957777504acffac557263e20c11001977bc"
+checksum = "72753e0008ea87963d2f0770042d0df7abe51fafbb8dcaf618ac440f2f1fec0a"
 dependencies = [
  "cc",
+ "pkg-config",
 ]
 
 [[package]]
 name = "libdeflater"
-version = "1.20.0"
+version = "1.25.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8dfd6424f7010ee0a3416f1d796d0450e3ad3ac237a237644f728277c4ded016"
+checksum = "d1ee41cf6fb1bb6030dfb59ffb7bc01ab26aade44142084c87f0fc7a1658fe71"
 dependencies = [
  "libdeflate-sys",
 ]
 
 [[package]]
 name = "linux-raw-sys"
-version = "0.4.13"
+version = "0.12.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "01cda141df6706de531b6c46c3a33ecca755538219bd484262fa09410c13539c"
+checksum = "32a66949e030da00e8c7d4434b251670a91556f4144941d37452769c25d58a53"
 
 [[package]]
 name = "log"
-version = "0.4.21"
+version = "0.4.30"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "90ed8c1e510134f979dbc4f070f87d4313098b704861a105fe34231c70a3901c"
+checksum = "616ec5685824bcc94416c6d4a7a446eea774a31efd7062c8480ba6fd06d7a6e5"
+
+[[package]]
+name = "memchr"
+version = "2.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f8ca58f447f06ed17d5fc4043ce1b10dd205e060fb3ce5b979b8ed8e59ff3f79"
 
 [[package]]
 name = "miniz_oxide"
-version = "0.7.2"
+version = "0.8.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9d811f3e15f28568be3407c8e7fdb6514c1cda3cb30683f15b6a1a1dc4ea14a7"
+checksum = "1fa76a2c86f704bdb222d66965fb3d63269ce38518b83cb0575fca855ebb6316"
 dependencies = [
- "adler",
+ "adler2",
  "simd-adler32",
 ]
 
 [[package]]
-name = "num-traits"
+name = "moxcms"
-version = "0.2.18"
+version = "0.7.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "da0df0e5185db44f69b44f26786fe401b6c293d1907744beaa7fa62b2e5a517a"
+checksum = "ac9557c559cd6fc9867e122e20d2cbefc9ca29d80d027a8e39310920ed2f0a97"
+dependencies = [
+ "num-traits",
+ "pxfm",
+]
+
+[[package]]
+name = "num-traits"
+version = "0.2.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "071dfc062690e90b734c0b2273ce72ad0ffa95f0c74596bc250dcfd960262841"
 dependencies = [
  "autocfg",
 ]
 
+[[package]]
+name = "once_cell_polyfill"
+version = "1.70.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "384b8ab6d37215f3c5301a95a4accb5d64aa607f1fcb26a11b5303878451b4fe"
+
 [[package]]
 name = "oxipng"
-version = "9.1.1"
+version = "10.1.1"
 dependencies = [
  "bitvec",
  "clap",
- "clap_mangen",
- "crossbeam-channel",
  "env_logger",
- "filetime",
  "glob",
  "image",
  "indexmap",
  "libdeflater",
  "log",
+ "parse-size",
  "rayon",
  "rgb",
  "rustc-hash",
- "rustc_version",
+ "serde_json",
  "zopfli",
 ]
 
 [[package]]
-name = "png"
+name = "parse-size"
-version = "0.17.13"
+version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "06e4b0d3d1312775e782c86c91a111aa1f910cbb65e1337f9975b5f9a554b5e1"
+checksum = "487f2ccd1e17ce8c1bfab3a65c89525af41cfad4c8659021a1e9a2aacd73b89b"
+
+[[package]]
+name = "pkg-config"
+version = "0.3.33"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "19f132c84eca552bf34cab8ec81f1c1dcc229b811638f9d283dceabe58c5569e"
+
+[[package]]
+name = "png"
+version = "0.18.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "60769b8b31b2a9f263dae2776c37b1b28ae246943cf719eb6946a1db05128a61"
 dependencies = [
- "bitflags 1.3.2",
+ "bitflags",
  "crc32fast",
  "fdeflate",
  "flate2",
  "miniz_oxide",
 ]
 
+[[package]]
+name = "proc-macro2"
+version = "1.0.106"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8fd00f0bb2e90d81d1044c2b32617f68fcb9fa3bb7640c23e9c748e53fb30934"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "pxfm"
+version = "0.1.29"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e0c5ccf5294c6ccd63a74f1565028353830a9c2f5eb0c682c355c471726a6e3f"
+
+[[package]]
+name = "quote"
+version = "1.0.45"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "41f2619966050689382d2b44f664f4bc593e129785a36d6ee376ddf37259b924"
+dependencies = [
+ "proc-macro2",
+]
+
 [[package]]
 name = "radium"
 version = "0.7.0"
@@ -410,9 +461,9 @@ checksum = "dc33ff2d4973d518d823d61aa239014831e521c75da58e3df4840d3f47749d09"
 
 [[package]]
 name = "rayon"
-version = "1.10.0"
+version = "1.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b418a60154510ca1a002a752ca9714984e21e4241e804d32555251faf8b78ffa"
+checksum = "fb39b166781f92d482534ef4b4b1b2568f42613b53e5b6c160e24cfbfa30926d"
 dependencies = [
  "either",
  "rayon-core",
@@ -420,77 +471,95 @@ dependencies = [
 
 [[package]]
 name = "rayon-core"
-version = "1.12.1"
+version = "1.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1465873a3dfdaa8ae7cb14b4383657caab0b3e8a0aa9ae8e04b044854c8dfce2"
+checksum = "22e18b0f0062d30d4230b2e85ff77fdfe4326feb054b9783a3460d8435c8ab91"
 dependencies = [
  "crossbeam-deque",
  "crossbeam-utils",
 ]
 
-[[package]]
-name = "redox_syscall"
-version = "0.4.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4722d768eff46b75989dd134e5c353f0d6296e5aaa3132e776cbdb56be7731aa"
-dependencies = [
- "bitflags 1.3.2",
-]
-
 [[package]]
 name = "rgb"
-version = "0.8.37"
+version = "0.8.53"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "05aaa8004b64fd573fc9d002f4e632d51ad4f026c2b5ba95fcb6c2f32c2c47d8"
+checksum = "47b34b781b31e5d73e9fbc8689c70551fd1ade9a19e3e28cfec8580a79290cc4"
 dependencies = [
  "bytemuck",
 ]
 
-[[package]]
-name = "roff"
-version = "0.2.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b833d8d034ea094b1ea68aa6d5c740e0d04bad9d16568d08ba6f76823a114316"
-
 [[package]]
 name = "rustc-hash"
-version = "1.1.0"
+version = "2.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "08d43f7aa6b08d49f382cde6a7982047c3426db949b1424bc4b7ec9ae12c6ce2"
+checksum = "94300abf3f1ae2e2b8ffb7b58043de3d399c73fa6f4b73826402a5c457614dbe"
-
-[[package]]
-name = "rustc_version"
-version = "0.4.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bfa0f585226d2e68097d4f95d113b15b83a82e819ab25717ec0590d9584ef366"
-dependencies = [
- "semver",
-]
 
 [[package]]
 name = "rustix"
-version = "0.38.32"
+version = "1.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "65e04861e65f21776e67888bfbea442b3642beaa0138fdb1dd7a84a52dffdb89"
+checksum = "b6fe4565b9518b83ef4f91bb47ce29620ca828bd32cb7e408f0062e9930ba190"
 dependencies = [
- "bitflags 2.5.0",
+ "bitflags",
  "errno",
  "libc",
  "linux-raw-sys",
- "windows-sys 0.52.0",
+ "windows-sys",
 ]
 
 [[package]]
-name = "semver"
+name = "serde"
-version = "1.0.22"
+version = "1.0.228"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "92d43fe69e652f3df9bdc2b85b2854a0825b86e4fb76bc44d945137d053639ca"
+checksum = "9a8e94ea7f378bd32cbbd37198a4a91436180c5bb472411e48b5ec2e2124ae9e"
+dependencies = [
+ "serde_core",
+]
+
+[[package]]
+name = "serde_core"
+version = "1.0.228"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "41d385c7d4ca58e59fc732af25c3983b67ac852c1a25000afe1175de458b67ad"
+dependencies = [
+ "serde_derive",
+]
+
+[[package]]
+name = "serde_derive"
+version = "1.0.228"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d540f220d3187173da220f885ab66608367b6574e925011a9353e4badda91d79"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "serde_json"
+version = "1.0.150"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e8014e44b4736ed0538adeecded0fce2a272f22dc9578a7eb6b2d9993c74cfb9"
+dependencies = [
+ "itoa",
+ "memchr",
+ "serde",
+ "serde_core",
+ "zmij",
+]
+
+[[package]]
+name = "shlex"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0fda2ff0d084019ba4d7c6f371c95d8fd75ce3524c3cb8fb653a3023f6323e64"
 
 [[package]]
 name = "simd-adler32"
-version = "0.3.7"
+version = "0.3.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d66dc143e6b11c1eddc06d5c423cfc97062865baf299914ab64caa38182078fe"
+checksum = "703d5c7ef118737c72f1af64ad2f6f8c5e1921f818cdcb97b8fe6fc69bf66214"
 
 [[package]]
 name = "strsim"
@@ -498,6 +567,17 @@ version = "0.11.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7da8b5736845d9f2fcb837ea5d9e2628564b3b043a70948a3f0b778838c5fb4f"
 
+[[package]]
+name = "syn"
+version = "2.0.117"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e665b8803e7b1d2a727f4023456bbbbe74da67099c585258af0ad9c5013b9b99"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
 [[package]]
 name = "tap"
 version = "1.0.1"
@@ -506,165 +586,41 @@ checksum = "55937e1799185b12863d447f42597ed69d9928686b8d88a1df17376a097d8369"
 
 [[package]]
 name = "terminal_size"
-version = "0.3.0"
+version = "0.4.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "21bebf2b7c9e0a515f6e0f8c51dc0f8e4696391e6f1ff30379559f8365fb0df7"
+checksum = "230a1b821ccbd75b185820a1f1ff7b14d21da1e442e22c0863ea5f08771a8874"
 dependencies = [
  "rustix",
- "windows-sys 0.48.0",
+ "windows-sys",
 ]
 
 [[package]]
-name = "typed-arena"
+name = "unicode-ident"
-version = "2.0.2"
+version = "1.0.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6af6ae20167a9ece4bcb41af5b80f8a1f1df981f6391189ce00fd257af04126a"
+checksum = "e6e4313cd5fcd3dad5cafa179702e2b244f760991f45397d14d4ebf38247da75"
 
 [[package]]
 name = "utf8parse"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "06abde3611657adf66d383f00b093d7faecc7fa57071cce2578660c9f1010821"
+
+[[package]]
+name = "windows-link"
 version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "711b9620af191e0cdc7468a8d14e709c3dcdb115b36f838e601583af800a370a"
+checksum = "f0805222e57f7521d6a62e36fa9163bc891acd422f971defe97d64e70d0a4fe5"
 
 [[package]]
 name = "windows-sys"
-version = "0.48.0"
+version = "0.61.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "677d2418bec65e3338edb076e806bc1ec15693c5d0104683f2efe857f61056a9"
+checksum = "ae137229bcbd6cdf0f7b80a31df61766145077ddf49416a728b02cb3921ff3fc"
 dependencies = [
- "windows-targets 0.48.5",
+ "windows-link",
 ]
 
-[[package]]
-name = "windows-sys"
-version = "0.52.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "282be5f36a8ce781fad8c8ae18fa3f9beff57ec1b52cb3de0789201425d9a33d"
-dependencies = [
- "windows-targets 0.52.5",
-]
-
-[[package]]
-name = "windows-targets"
-version = "0.48.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9a2fa6e2155d7247be68c096456083145c183cbbbc2764150dda45a87197940c"
-dependencies = [
- "windows_aarch64_gnullvm 0.48.5",
- "windows_aarch64_msvc 0.48.5",
- "windows_i686_gnu 0.48.5",
- "windows_i686_msvc 0.48.5",
- "windows_x86_64_gnu 0.48.5",
- "windows_x86_64_gnullvm 0.48.5",
- "windows_x86_64_msvc 0.48.5",
-]
-
-[[package]]
-name = "windows-targets"
-version = "0.52.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6f0713a46559409d202e70e28227288446bf7841d3211583a4b53e3f6d96e7eb"
-dependencies = [
- "windows_aarch64_gnullvm 0.52.5",
- "windows_aarch64_msvc 0.52.5",
- "windows_i686_gnu 0.52.5",
- "windows_i686_gnullvm",
- "windows_i686_msvc 0.52.5",
- "windows_x86_64_gnu 0.52.5",
- "windows_x86_64_gnullvm 0.52.5",
- "windows_x86_64_msvc 0.52.5",
-]
-
-[[package]]
-name = "windows_aarch64_gnullvm"
-version = "0.48.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2b38e32f0abccf9987a4e3079dfb67dcd799fb61361e53e2882c3cbaf0d905d8"
-
-[[package]]
-name = "windows_aarch64_gnullvm"
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-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7088eed71e8b8dda258ecc8bac5fb1153c5cffaf2578fc8ff5d61e23578d3263"
-
-[[package]]
-name = "windows_aarch64_msvc"
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-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dc35310971f3b2dbbf3f0690a219f40e2d9afcf64f9ab7cc1be722937c26b4bc"
-
-[[package]]
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-checksum = "9985fd1504e250c615ca5f281c3f7a6da76213ebd5ccc9561496568a2752afb6"
-
-[[package]]
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-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a75915e7def60c94dcef72200b9a8e58e5091744960da64ec734a6c6e9b3743e"
-
-[[package]]
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-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "88ba073cf16d5372720ec942a8ccbf61626074c6d4dd2e745299726ce8b89670"
-
-[[package]]
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-checksum = "87f4261229030a858f36b459e748ae97545d6f1ec60e5e0d6a3d32e0dc232ee9"
-
-[[package]]
-name = "windows_i686_msvc"
-version = "0.48.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8f55c233f70c4b27f66c523580f78f1004e8b5a8b659e05a4eb49d4166cca406"
-
-[[package]]
-name = "windows_i686_msvc"
-version = "0.52.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "db3c2bf3d13d5b658be73463284eaf12830ac9a26a90c717b7f771dfe97487bf"
-
-[[package]]
-name = "windows_x86_64_gnu"
-version = "0.48.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "53d40abd2583d23e4718fddf1ebec84dbff8381c07cae67ff7768bbf19c6718e"
-
-[[package]]
-name = "windows_x86_64_gnu"
-version = "0.52.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4e4246f76bdeff09eb48875a0fd3e2af6aada79d409d33011886d3e1581517d9"
-
-[[package]]
-name = "windows_x86_64_gnullvm"
-version = "0.48.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0b7b52767868a23d5bab768e390dc5f5c55825b6d30b86c844ff2dc7414044cc"
-
-[[package]]
-name = "windows_x86_64_gnullvm"
-version = "0.52.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "852298e482cd67c356ddd9570386e2862b5673c85bd5f88df9ab6802b334c596"
-
-[[package]]
-name = "windows_x86_64_msvc"
-version = "0.48.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ed94fce61571a4006852b7389a063ab983c02eb1bb37b47f8272ce92d06d9538"
-
-[[package]]
-name = "windows_x86_64_msvc"
-version = "0.52.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bec47e5bfd1bff0eeaf6d8b485cc1074891a197ab4225d504cb7a1ab88b02bf0"
-
 [[package]]
 name = "wyz"
 version = "0.5.1"
@@ -675,13 +631,19 @@ dependencies = [
 ]
 
 [[package]]
-name = "zopfli"
+name = "zmij"
-version = "0.8.0"
+version = "1.0.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5c1f48f3508a3a3f2faee01629564400bc12260f6214a056d06a3aaaa6ef0736"
+checksum = "b8848ee67ecc8aedbaf3e4122217aff892639231befc6a1b58d29fff4c2cabaa"
+
+[[package]]
+name = "zopfli"
+version = "0.8.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f05cd8797d63865425ff89b5c4a48804f35ba0ce8d125800027ad6017d2b5249"
 dependencies = [
+ "bumpalo",
  "crc32fast",
  "log",
  "simd-adler32",
- "typed-arena",
 ]

Cargo.toml

@@ -2,8 +2,9 @@
 authors = ["Joshua Holmer <jholmer.in@gmail.com>"]
 categories = ["command-line-utilities", "compression"]
 description = "A lossless PNG compression optimizer"
+keywords = ["png", "image-compression", "optimization", "multi-threading", "lossless"]
 documentation = "https://docs.rs/oxipng"
-edition = "2021"
+edition = "2024"
 exclude = [
   ".editorconfig",
   ".gitattributes",
@@ -13,16 +14,17 @@ exclude = [
   "Dockerfile",
   "scripts/*",
   "tests/*",
+  "xtask/*",
 ]
-homepage = "https://github.com/shssoichiro/oxipng"
+homepage = "https://github.com/oxipng/oxipng"
 license = "MIT"
 name = "oxipng"
-repository = "https://github.com/shssoichiro/oxipng"
+repository = "https://github.com/oxipng/oxipng"
-version = "9.1.1"
+version = "10.1.1"
-rust-version = "1.74.0"
+rust-version = "1.85.1"
 
 [badges]
-travis-ci = { repository = "shssoichiro/oxipng", branch = "master" }
+travis-ci = { repository = "oxipng/oxipng", branch = "master" }
 maintenance = { status = "actively-developed" }
 
 [[bin]]
@@ -36,58 +38,33 @@ name = "zopfli"
 required-features = ["zopfli"]
 
 [dependencies]
-zopfli = { version = "0.8.0", optional = true, default-features = false, features = ["std", "zlib"] }
-rgb = "0.8.37"
-indexmap = "2.2.6"
-libdeflater = "1.20.0"
-log = "0.4.21"
 bitvec = "1.0.1"
-rustc-hash = "1.1.0"
+clap = { version = "4.6.0", optional = true, features = ["wrap_help"] }
+env_logger = { version = "0.11.10", optional = true, default-features = false, features = ["auto-color"] }
+image = { version = "0.25.9", optional = true, default-features = false, features = ["png"] }
+indexmap = "2.14.0"
+libdeflater = "1.25.2"
+log = "0.4.30"
+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"] }
 
-[dependencies.env_logger]
+[target.'cfg(windows)'.dependencies]
-optional = true
+glob = { version = "0.3.3", optional = true }
-default-features = false
-features = ["auto-color"]
-version = "0.11.3"
 
-[dependencies.crossbeam-channel]
+[dev-dependencies]
-optional = true
+serde_json = "1.0.150"
-version = "0.5.12"
-
-[dependencies.filetime]
-optional = true
-version = "0.2.23"
-
-[dependencies.rayon]
-optional = true
-version = "1.10.0"
-
-[dependencies.clap]
-optional = true
-version = "4.5.4"
-features = ["wrap_help"]
-
-[target.'cfg(windows)'.dependencies.glob]
-optional = true
-version = "0.3.1"
-
-[dependencies.image]
-optional = true
-default-features = false
-features = ["png"]
-version = "0.25.1"
-
-[build-dependencies]
-clap = "4.5.4"
-clap_mangen = "0.2.20"
-rustc_version = "0.4.0"
 
 [features]
-binary = ["clap", "glob", "env_logger"]
+binary = ["dep:clap", "dep:glob", "dep:env_logger", "dep:parse-size"]
-default = ["binary", "filetime", "parallel", "zopfli"]
+default = ["binary", "parallel", "zopfli"]
-parallel = ["rayon", "indexmap/rayon", "crossbeam-channel"]
+parallel = ["dep:rayon", "indexmap/rayon"]
 freestanding = ["libdeflater/freestanding"]
-sanity-checks = ["image"]
+sanity-checks = ["dep:image"]
+zopfli = ["dep:zopfli"]
+system-libdeflate = ["libdeflater/dynamic"]
 
 [lib]
 name = "oxipng"
@@ -104,7 +81,41 @@ panic = "abort"
 [package.metadata.deb]
 assets = [
     ["target/release/oxipng", "usr/bin/", "755"],
-    ["target/release/assets/oxipng.1", "usr/share/man/man1/", "644"],
+    ["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

@@ -1,20 +1,46 @@
-FROM rust:alpine as base
+# syntax=docker/dockerfile:1
+# check=error=true
+FROM --platform=$BUILDPLATFORM tonistiigi/xx AS xx
 
-COPY . /src
+FROM --platform=$BUILDPLATFORM rust:1.85.1-alpine AS base
 
-RUN rustup update 1.74 && rustup default 1.74
+RUN apk update && \
-
+    apk add \
-RUN apk update \
-    && apk add \
         gcc \
-        g++
+        g++ \
+        clang
 
-RUN cd /src && cargo build --release
+COPY --from=xx / /
 
-FROM alpine as tool
+ARG TARGETPLATFORM
+RUN xx-info env
 
-COPY --from=base /src/target/release/oxipng /usr/local/bin
+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

@@ -1,4 +1,4 @@
-oxipng 9.1.1
+oxipng 10.1.0
 Losslessly improve compression of PNG files
 
 Usage: oxipng [OPTIONS] <files>...
@@ -13,14 +13,14 @@ Options:
           compression. Lower levels are faster, higher levels provide better compression, though
           with increasingly diminishing returns.
           
-              0   => --zc 5 --fast               (1 trial, determined heuristically)
+              0   => --zc 5  --fast              (filter chosen heuristically)
-              1   => --zc 10 --fast              (1 trial, determined heuristically)
+              1   => --zc 10 --fast              (filter chosen heuristically)
-              2   => --zc 11 -f 0,1,6,7 --fast   (4 fast trials, 1 main trial)
+              2   => --zc 11 -f 0,1,6,7 --fast
-              3   => --zc 11 -f 0,7,8,9          (4 trials)
+              3   => --zc 11 -f 0,7,8,9         --brute-level 1 --brute-lines 3
-              4   => --zc 12 -f 0,7,8,9          (4 trials)
+              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  (8 trials)
+              5   => --zc 12 -f 0,1,2,5,6,7,8,9 --brute-level 4 --brute-lines 4
-              6   => --zc 12 -f 0-9              (10 trials)
+              6   => --zc 12 -f 0-9             --brute-level 5 --brute-lines 8
-              max =>                             (stable alias for the max level)
+              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.
@@ -45,7 +45,7 @@ Options:
   -p, --preserve
           Preserve file permissions and timestamps if possible
 
-  -P, --pretend
+  -d, --dry-run
           Do not write any files, only show compression results
 
   -s
@@ -61,10 +61,14 @@ Options:
           
           CAUTION: 'all' will convert APNGs to standard PNGs.
           
-          Note that 'bKGD', 'sBIT' and 'hIST' will be forcibly stripped if the color type or bit
+          Please note that regardless of any options set, some chunks will necessarily be stripped
-          depth is changed, regardless of any options set.
+          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 metadata.
+          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
@@ -79,17 +83,17 @@ Options:
           but take care as while this is “visually lossless”, it is technically a lossy
           transformation and may be unsuitable for some applications.
 
-  -i, --interlace <type>
+  -i, --interlace <mode>
-          Set the PNG interlacing type, where <type> is one of:
+          Set the PNG interlacing mode, where <mode> is one of:
           
-              0     =>  Remove interlacing from all images that are processed
+              off   =>  Remove interlacing from all images that are processed
-              1     =>  Apply Adam7 interlacing on all images that are processed
+              on    =>  Apply Adam7 interlacing on all images that are processed
-              keep  =>  Keep the existing interlacing type of each image
+              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: 0]
+          [default: off]
 
       --scale16
           Forcibly reduce images with 16 bits per channel to 8 bits per channel. This is a lossy
@@ -101,10 +105,13 @@ Options:
           losslessly.
 
   -v, --verbose...
-          Run in verbose mode (use twice to increase verbosity)
+          Show per-file info (use multiple times for more detail)
 
   -q, --quiet
-          Run in quiet mode
+          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
@@ -119,9 +126,9 @@ Options:
           
           Heuristic strategies (try to find the best delta filter for each line)
               5  =>  MinSum    Minimum sum of absolute differences
-              6  =>  Entropy   Highest Shannon entropy
+              6  =>  Entropy   Smallest Shannon entropy
               7  =>  Bigrams   Lowest count of distinct bigrams
-              8  =>  BigEnt    Highest Shannon entropy of bigrams
+              8  =>  BigEnt    Smallest Shannon entropy of bigrams
               9  =>  Brute     Smallest compressed size (slow)
           
           The default value depends on the optimization level preset.
@@ -132,7 +139,7 @@ Options:
           CPU cores.
 
       --zc <level>
-          Deflate compression level (1-12) for main compression trials. The levels here are defined
+          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.
@@ -159,15 +166,33 @@ Options:
 
       --fix
           Do not perform checksum validation of PNG chunks. This may allow some files with errors to
-          be processed successfully.
+          be processed successfully. The output will always have correct checksums.
 
       --force
           Write the output even if it is larger than the input
 
-  -Z, --zopfli
+  -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
@@ -175,8 +200,25 @@ Options:
           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 number of threads to use [default: num CPU cores]
+          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')

README.md

@@ -1,41 +1,46 @@
 # Oxipng
 
-[![Build Status](https://github.com/shssoichiro/oxipng/workflows/oxipng/badge.svg)](https://github.com/shssoichiro/oxipng/actions?query=branch%3Amaster)
+[![Build Status](https://github.com/oxipng/oxipng/workflows/oxipng/badge.svg)](https://github.com/oxipng/oxipng/actions?query=branch%3Amaster)
 [![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)
+[![License](https://img.shields.io/crates/l/oxipng.svg)](https://github.com/oxipng/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
-interface or as a library in other Rust programs.
+interface or as a library in other Rust programs. It is fast and highly effective.
 
 ## Installing
 
-Oxipng for Windows can be downloaded from the [Releases](https://github.com/shssoichiro/oxipng/releases) link on the GitHub page.
+Oxipng for Windows can be downloaded via the
+[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
+For MacOS or Linux, it is recommended to install from your distro's package repository, provided
-repository, if possible. Oxipng is known to be packaged for the environments listed below.
+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:
+Alternatively, Oxipng can be installed from Cargo, via the following command:
 
 ```
 cargo install oxipng
 ```
 
-Oxipng can be built from source using the latest stable or nightly Rust.
+Oxipng can also be built from source using the latest stable or nightly Rust.
-This is primarily useful for developing on oxipng.
+This is primarily useful for developing on Oxipng.
 
 ```
-git clone https://github.com/shssoichiro/oxipng.git
+git clone https://github.com/oxipng/oxipng.git
 cd oxipng
 cargo build --release
 cp target/release/oxipng /usr/local/bin
 ```
 
-The current minimum supported Rust version is **1.74.0**.
+The current minimum supported Rust version is **1.85.1**.
 
 Oxipng follows Semantic Versioning.
 
@@ -51,7 +56,7 @@ The most commonly used options are as follows:
 
 - Optimization: `-o 0` through `-o 6` (or `-o max`), lower is faster, higher is better compression.
   The default (`-o 2`) is quite fast and provides good compression. Higher levels can be notably
-  better but generally have increasingly diminishing returns.
+  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
@@ -66,7 +71,19 @@ More advanced options can be found by running `oxipng --help`, or viewed [here](
 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`.
-Note that all options are case-sensitive.
+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]
 
@@ -75,83 +92,59 @@ preamble to an already existing one:
 
 ```yaml
 repos:
-  - repo: https://github.com/shssoichiro/oxipng
+  - repo: https://github.com/oxipng/oxipng
-    rev: v9.0.0
+    rev: v10.0.0
     hooks:
       - id: oxipng
         args: ["-o", "4", "--strip", "safe", "--alpha"]
 ```
 [pre-commit]: https://pre-commit.com/
 
-## Git integration via [Trunk]
+## Docker
 
-[Trunk] is an extendable superlinter which can be used to run `oxipng` to automatically optimize `png`s when committing them into a git repo, or to gate any `png`s being added to a git repo on whether they are optimized. The [trunk] oxipng integration is [here](https://github.com/trunk-io/plugins/tree/main/linters/oxipng).
+A Docker image is availlable at [`ghcr.io/oxipng/oxipng`](https://github.com/oxipng/oxipng/pkgs/container/oxipng) for `linux/amd64` and `linux/arm64`.
 
-To enable oxipng via [trunk]:
+You can use it the following way:
 
 ```bash
-# to get the latest version:
+docker run --rm -v $(pwd):/work ghcr.io/oxipng/oxipng -o 4 /work/file.png
-trunk check enable oxipng
-
-# to get a specific version:
-trunk check enable oxipng@9.0.0
 ```
 
-or modify `.trunk/trunk.yaml` in your repo to contain:
+Some older images are also available at [`ghcr.io/shssoichiro/oxipng`](https://github.com/users/shssoichiro/packages/container/package/oxipng).
-
-```
-lint:
-  enabled:
-    - oxipng@9.0.0
-```
-
-Then just run:
-
-```bash
-# to optimize a png:
-trunk fmt <file>
-
-# to check if a png is already optimized:
-trunk check <file>
-```
-
-You can setup [trunk] to [manage your git hooks](https://docs.trunk.io/docs/actions-git-hooks) and automatically optimize any `png`s you commit to git, _when_ you `git commit`. To enable this, run:
-
-```bash
-trunk actions enable trunk-fmt-pre-commit
-```
-
-[trunk]: https://docs.trunk.io
 
 ## 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,
+other Rust projects. To do so, simply add Oxipng as a dependency in your Cargo.toml. You should then
-then `extern crate oxipng` in your project. You should then have access to all of the library
+have access to all of the library functions [documented here](https://docs.rs/oxipng). The simplest
-functions [documented here](https://docs.rs/oxipng). The simplest
+method of usage involves creating an [Options
-method of usage involves creating an
+struct](https://docs.rs/oxipng/latest/oxipng/struct.Options.html) and passing it, along with an
-[Options struct](https://docs.rs/oxipng/latest/oxipng/struct.Options.html) and
+input filename, into the [optimize function](https://docs.rs/oxipng/latest/oxipng/fn.optimize.html).
-passing it, along with an input filename, into the
-[optimize function](https://docs.rs/oxipng/latest/oxipng/fn.optimize.html).
 
-It is recommended to disable the "binary" feature when including oxipng as a library. Currently, there is
+It is recommended to disable the "binary" feature when including Oxipng as a library. Currently, there is
 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 = "9.0", features = ["parallel", "zopfli", "filetime"], default-features = false }`
+`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 as a complete rewrite of the OptiPNG project,
+Oxipng began in 2015 as a rewrite of the OptiPNG project. The core goal was to implement
-which was assumed to be dead as no commit had been made to it since March 2014.
+multithreading, which would have been very difficult to do within the existing C codebase of OptiPNG.
-(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).
 
-Note that, while similar, Oxipng is not a drop-in replacement for OptiPNG.
+However, Oxipng has evolved considerably since then. While some of the options remain similar to
-If you are migrating from OptiPNG, please check the [help](MANUAL.txt) before using.
+OptiPNG, the architecture and capabilities are now quite different. It is not a drop-in
+replacement - if you are migrating from OptiPNG, please check the [help](MANUAL.txt) before use.
 
 ## Contributing
 
@@ -161,78 +154,11 @@ 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 9.0.0 (commit `c16519b38b0519988db625913be919d4f0e42f5d`, compiled
-on `rustc 1.74.0-nightly (7b4d9e155 2023-09-28)`) against OptiPNG version 0.7.7,
-as packaged by Debian unstable, on a Linux 6.5.0-2-amd64 kernel, Intel Core
-i7-12700 CPU (8 performance cores, 4 efficiency cores, 20 threads), DDR5-5200
-RAM in dual channel configuration.
-
-```
-
-Benchmark 1: ./target/release/oxipng -P ./tests/files/rgb_16_should_be_grayscale_8.png
-  Time (mean ± σ):      59.6 ms ±   7.7 ms    [User: 77.4 ms, System: 3.6 ms]
-  Range (min … max):    53.3 ms …  89.9 ms    32 runs
-
-Benchmark 2: optipng -simulate ./tests/files/rgb_16_should_be_grayscale_8.png
-  Time (mean ± σ):     132.4 ms ±   0.8 ms    [User: 132.5 ms, System: 0.6 ms]
-  Range (min … max):   131.8 ms … 134.4 ms    22 runs
-
-Summary
-  ./target/release/oxipng -P ./tests/files/rgb_16_should_be_grayscale_8.png ran
-    2.22 ± 0.29 times 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):      88.7 ms ±   4.3 ms    [User: 270.3 ms, System: 11.0 ms]
-  Range (min … max):    86.8 ms … 109.4 ms    26 runs
-
-Benchmark 2: optipng -o 4 -simulate ./tests/files/rgb_16_should_be_grayscale_8.png
-  Time (mean ± σ):     444.9 ms ±   0.3 ms    [User: 444.8 ms, System: 0.7 ms]
-  Range (min … max):   444.4 ms … 445.6 ms    10 runs
-
-Summary
-  ./target/release/oxipng -o4 -P ./tests/files/rgb_16_should_be_grayscale_8.png ran
-    5.01 ± 0.25 times faster than optipng -o 4 -simulate ./tests/files/rgb_16_should_be_grayscale_8.png
-
-```
-
-<details>
-<summary>Older benchmark</summary>
-
-Tested oxipng 5.0.0 (compiled on rustc 1.55.0-nightly (7a16cfcff 2021-07-11)) against OptiPNG version 0.7.7 on AMD Ryzen 7 4800H with Radeon Graphics with 16 logical cores
-
-```
-
-Benchmark #1: ./target/release/oxipng -P ./tests/files/rgb_16_should_be_grayscale_8.png
-  Time (mean ± σ):     128.8 ms ±  14.2 ms    [User: 296.0 ms, System: 14.3 ms]
-  Range (min … max):    98.8 ms … 152.3 ms    21 runs
-
-Benchmark #2: optipng -simulate ./tests/files/rgb_16_should_be_grayscale_8.png
-  Time (mean ± σ):     254.2 ms ±  16.0 ms    [User: 252.8 ms, System: 1.2 ms]
-  Range (min … max):   208.4 ms … 263.8 ms    14 runs
-
-Summary
-  './target/release/oxipng -P ./tests/files/rgb_16_should_be_grayscale_8.png' ran
-    1.97 ± 0.25 times 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):     141.4 ms ±  14.9 ms    [User: 611.7 ms, System: 21.1 ms]
-  Range (min … max):   100.2 ms … 160.4 ms    23 runs
-
-Benchmark #2: optipng -o 4 -simulate ./tests/files/rgb_16_should_be_grayscale_8.png
-  Time (mean ± σ):     730.0 ms ±  25.9 ms    [User: 728.0 ms, System: 1.2 ms]
-  Range (min … max):   713.3 ms … 768.2 ms    10 runs
-
-Summary
-  './target/release/oxipng -o4 -P ./tests/files/rgb_16_should_be_grayscale_8.png' ran
-    5.16 ± 0.58 times faster than 'optipng -o 4 -simulate ./tests/files/rgb_16_should_be_grayscale_8.png'
-
-```
-</details>

SECURITY.md

@@ -0,0 +1,13 @@
+# 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.

benches/deflate.rs

@@ -13,10 +13,7 @@ fn deflate_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();
 
-    b.iter(|| {
+    b.iter(|| deflate(png.raw.data.as_ref(), 12, None));
-        let min = AtomicMin::new(None);
-        deflate(png.raw.data.as_ref(), 12, &min)
-    });
 }
 
 #[bench]
@@ -24,10 +21,7 @@ fn deflate_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();
 
-    b.iter(|| {
+    b.iter(|| deflate(png.raw.data.as_ref(), 12, None));
-        let min = AtomicMin::new(None);
-        deflate(png.raw.data.as_ref(), 12, &min)
-    });
 }
 
 #[bench]
@@ -37,10 +31,7 @@ fn deflate_4_bits(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| {
+    b.iter(|| deflate(png.raw.data.as_ref(), 12, None));
-        let min = AtomicMin::new(None);
-        deflate(png.raw.data.as_ref(), 12, &min)
-    });
 }
 
 #[bench]
@@ -50,10 +41,7 @@ fn deflate_2_bits(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| {
+    b.iter(|| deflate(png.raw.data.as_ref(), 12, None));
-        let min = AtomicMin::new(None);
-        deflate(png.raw.data.as_ref(), 12, &min)
-    });
 }
 
 #[bench]
@@ -63,10 +51,7 @@ fn deflate_1_bits(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| {
+    b.iter(|| deflate(png.raw.data.as_ref(), 12, None));
-        let min = AtomicMin::new(None);
-        deflate(png.raw.data.as_ref(), 12, &min)
-    });
 }
 
 #[bench]

benches/filters.rs

@@ -13,9 +13,7 @@ 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();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::NONE, false));
-        png.raw.filter_image(RowFilter::None, false);
-    });
 }
 
 #[bench]
@@ -23,9 +21,7 @@ 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();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::NONE, false));
-        png.raw.filter_image(RowFilter::None, false);
-    });
 }
 
 #[bench]
@@ -35,9 +31,7 @@ fn filters_4_bits_filter_0(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::NONE, false));
-        png.raw.filter_image(RowFilter::None, false);
-    });
 }
 
 #[bench]
@@ -47,9 +41,7 @@ fn filters_2_bits_filter_0(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::NONE, false));
-        png.raw.filter_image(RowFilter::None, false);
-    });
 }
 
 #[bench]
@@ -59,9 +51,7 @@ fn filters_1_bits_filter_0(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::NONE, false));
-        png.raw.filter_image(RowFilter::None, false);
-    });
 }
 
 #[bench]
@@ -69,9 +59,7 @@ 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();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::SUB, false));
-        png.raw.filter_image(RowFilter::Sub, false);
-    });
 }
 
 #[bench]
@@ -79,9 +67,7 @@ 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();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::SUB, false));
-        png.raw.filter_image(RowFilter::Sub, false);
-    });
 }
 
 #[bench]
@@ -91,9 +77,7 @@ fn filters_4_bits_filter_1(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::SUB, false));
-        png.raw.filter_image(RowFilter::Sub, false);
-    });
 }
 
 #[bench]
@@ -103,9 +87,7 @@ fn filters_2_bits_filter_1(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::SUB, false));
-        png.raw.filter_image(RowFilter::Sub, false);
-    });
 }
 
 #[bench]
@@ -115,9 +97,7 @@ fn filters_1_bits_filter_1(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::SUB, false));
-        png.raw.filter_image(RowFilter::Sub, false);
-    });
 }
 
 #[bench]
@@ -125,9 +105,7 @@ 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();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::UP, false));
-        png.raw.filter_image(RowFilter::Up, false);
-    });
 }
 
 #[bench]
@@ -135,9 +113,7 @@ 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();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::UP, false));
-        png.raw.filter_image(RowFilter::Up, false);
-    });
 }
 
 #[bench]
@@ -147,9 +123,7 @@ fn filters_4_bits_filter_2(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::UP, false));
-        png.raw.filter_image(RowFilter::Up, false);
-    });
 }
 
 #[bench]
@@ -159,9 +133,7 @@ fn filters_2_bits_filter_2(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::UP, false));
-        png.raw.filter_image(RowFilter::Up, false);
-    });
 }
 
 #[bench]
@@ -171,9 +143,7 @@ fn filters_1_bits_filter_2(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::UP, false));
-        png.raw.filter_image(RowFilter::Up, false);
-    });
 }
 
 #[bench]
@@ -181,9 +151,7 @@ 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();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::AVERAGE, false));
-        png.raw.filter_image(RowFilter::Average, false);
-    });
 }
 
 #[bench]
@@ -191,9 +159,7 @@ 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();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::AVERAGE, false));
-        png.raw.filter_image(RowFilter::Average, false);
-    });
 }
 
 #[bench]
@@ -203,9 +169,7 @@ fn filters_4_bits_filter_3(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::AVERAGE, false));
-        png.raw.filter_image(RowFilter::Average, false);
-    });
 }
 
 #[bench]
@@ -215,9 +179,7 @@ fn filters_2_bits_filter_3(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::AVERAGE, false));
-        png.raw.filter_image(RowFilter::Average, false);
-    });
 }
 
 #[bench]
@@ -227,9 +189,7 @@ fn filters_1_bits_filter_3(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::AVERAGE, false));
-        png.raw.filter_image(RowFilter::Average, false);
-    });
 }
 
 #[bench]
@@ -237,9 +197,7 @@ 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();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::PAETH, false));
-        png.raw.filter_image(RowFilter::Paeth, false);
-    });
 }
 
 #[bench]
@@ -247,9 +205,7 @@ 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();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::PAETH, false));
-        png.raw.filter_image(RowFilter::Paeth, false);
-    });
 }
 
 #[bench]
@@ -259,9 +215,7 @@ fn filters_4_bits_filter_4(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::PAETH, false));
-        png.raw.filter_image(RowFilter::Paeth, false);
-    });
 }
 
 #[bench]
@@ -271,9 +225,7 @@ fn filters_2_bits_filter_4(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::PAETH, false));
-        png.raw.filter_image(RowFilter::Paeth, false);
-    });
 }
 
 #[bench]
@@ -283,9 +235,7 @@ fn filters_1_bits_filter_4(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::PAETH, false));
-        png.raw.filter_image(RowFilter::Paeth, false);
-    });
 }
 
 #[bench]
@@ -293,9 +243,7 @@ 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();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::MinSum, false));
-        png.raw.filter_image(RowFilter::MinSum, false);
-    });
 }
 
 #[bench]
@@ -303,9 +251,7 @@ 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();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::MinSum, false));
-        png.raw.filter_image(RowFilter::MinSum, false);
-    });
 }
 
 #[bench]
@@ -315,9 +261,7 @@ fn filters_4_bits_filter_5(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::MinSum, false));
-        png.raw.filter_image(RowFilter::MinSum, false);
-    });
 }
 
 #[bench]
@@ -327,9 +271,7 @@ fn filters_2_bits_filter_5(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::MinSum, false));
-        png.raw.filter_image(RowFilter::MinSum, false);
-    });
 }
 
 #[bench]
@@ -339,7 +281,5 @@ fn filters_1_bits_filter_5(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::MinSum, false));
-        png.raw.filter_image(RowFilter::MinSum, false);
-    });
 }

benches/interlacing.rs

@@ -13,7 +13,7 @@ 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();
 
-    b.iter(|| png.raw.change_interlacing(Interlacing::Adam7));
+    b.iter(|| png.raw.change_interlacing(true));
 }
 
 #[bench]
@@ -21,7 +21,7 @@ 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();
 
-    b.iter(|| png.raw.change_interlacing(Interlacing::Adam7));
+    b.iter(|| png.raw.change_interlacing(true));
 }
 
 #[bench]
@@ -31,7 +31,7 @@ fn interlacing_4_bits(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(Interlacing::Adam7));
+    b.iter(|| png.raw.change_interlacing(true));
 }
 
 #[bench]
@@ -41,7 +41,7 @@ fn interlacing_2_bits(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(Interlacing::Adam7));
+    b.iter(|| png.raw.change_interlacing(true));
 }
 
 #[bench]
@@ -51,7 +51,7 @@ fn interlacing_1_bits(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(Interlacing::Adam7));
+    b.iter(|| png.raw.change_interlacing(true));
 }
 
 #[bench]
@@ -61,7 +61,7 @@ fn deinterlacing_16_bits(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(Interlacing::None));
+    b.iter(|| png.raw.change_interlacing(false));
 }
 
 #[bench]
@@ -71,7 +71,7 @@ fn deinterlacing_8_bits(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(Interlacing::None));
+    b.iter(|| png.raw.change_interlacing(false));
 }
 
 #[bench]
@@ -81,7 +81,7 @@ fn deinterlacing_4_bits(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(Interlacing::None));
+    b.iter(|| png.raw.change_interlacing(false));
 }
 
 #[bench]
@@ -91,7 +91,7 @@ fn deinterlacing_2_bits(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(Interlacing::None));
+    b.iter(|| png.raw.change_interlacing(false));
 }
 
 #[bench]
@@ -101,5 +101,5 @@ fn deinterlacing_1_bits(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(Interlacing::None));
+    b.iter(|| png.raw.change_interlacing(false));
 }

benches/reductions.rs

@@ -54,36 +54,6 @@ fn reductions_8_to_1_bits(b: &mut Bencher) {
     b.iter(|| bit_depth::reduced_bit_depth_8_or_less(&png.raw));
 }
 
-#[bench]
-fn reductions_4_to_2_bits(b: &mut Bencher) {
-    let input = test::black_box(PathBuf::from(
-        "tests/files/palette_4_should_be_palette_2.png",
-    ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
-
-    b.iter(|| bit_depth::reduced_bit_depth_8_or_less(&png.raw));
-}
-
-#[bench]
-fn reductions_4_to_1_bits(b: &mut Bencher) {
-    let input = test::black_box(PathBuf::from(
-        "tests/files/palette_4_should_be_palette_1.png",
-    ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
-
-    b.iter(|| bit_depth::reduced_bit_depth_8_or_less(&png.raw));
-}
-
-#[bench]
-fn reductions_2_to_1_bits(b: &mut Bencher) {
-    let input = test::black_box(PathBuf::from(
-        "tests/files/palette_2_should_be_palette_1.png",
-    ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
-
-    b.iter(|| bit_depth::reduced_bit_depth_8_or_less(&png.raw));
-}
-
 #[bench]
 fn reductions_grayscale_8_to_4_bits(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
@@ -114,42 +84,12 @@ fn reductions_grayscale_8_to_1_bits(b: &mut Bencher) {
     b.iter(|| bit_depth::reduced_bit_depth_8_or_less(&png.raw));
 }
 
-#[bench]
-fn reductions_grayscale_4_to_2_bits(b: &mut Bencher) {
-    let input = test::black_box(PathBuf::from(
-        "tests/files/grayscale_4_should_be_grayscale_2.png",
-    ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
-
-    b.iter(|| bit_depth::reduced_bit_depth_8_or_less(&png.raw));
-}
-
-#[bench]
-fn reductions_grayscale_4_to_1_bits(b: &mut Bencher) {
-    let input = test::black_box(PathBuf::from(
-        "tests/files/grayscale_4_should_be_grayscale_1.png",
-    ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
-
-    b.iter(|| bit_depth::reduced_bit_depth_8_or_less(&png.raw));
-}
-
-#[bench]
-fn reductions_grayscale_2_to_1_bits(b: &mut Bencher) {
-    let input = test::black_box(PathBuf::from(
-        "tests/files/grayscale_2_should_be_grayscale_1.png",
-    ));
-    let png = PngData::new(&input, &Options::default()).unwrap();
-
-    b.iter(|| bit_depth::reduced_bit_depth_8_or_less(&png.raw));
-}
-
 #[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();
 
-    b.iter(|| alpha::reduced_alpha_channel(&png.raw, false));
+    b.iter(|| alpha::reduced_alpha_channel(&png.raw, true));
 }
 
 #[bench]
@@ -157,7 +97,15 @@ 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();
 
-    b.iter(|| alpha::reduced_alpha_channel(&png.raw, false));
+    b.iter(|| alpha::reduced_alpha_channel(&png.raw, true));
+}
+
+#[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]
@@ -180,32 +128,6 @@ fn reductions_rgba_to_grayscale_alpha_8(b: &mut Bencher) {
     b.iter(|| color::reduced_rgb_to_grayscale(&png.raw));
 }
 
-#[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, &Options::default()).unwrap();
-
-    b.iter(|| {
-        color::reduced_rgb_to_grayscale(&png.raw)
-            .and_then(|r| alpha::reduced_alpha_channel(&r, false))
-    });
-}
-
-#[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, &Options::default()).unwrap();
-
-    b.iter(|| {
-        color::reduced_rgb_to_grayscale(&png.raw)
-            .and_then(|r| alpha::reduced_alpha_channel(&r, false))
-    });
-}
-
 #[bench]
 fn reductions_rgb_to_grayscale_16(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from(
@@ -240,6 +162,36 @@ fn reductions_rgb_to_palette_8(b: &mut Bencher) {
     b.iter(|| color::reduced_to_indexed(&png.raw, true));
 }
 
+#[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(
@@ -257,7 +209,7 @@ fn reductions_palette_8_to_grayscale_8(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| color::indexed_to_channels(&png.raw, true));
+    b.iter(|| color::indexed_to_channels(&png.raw, true, false));
 }
 
 #[bench]

benches/strategies.rs

@@ -13,9 +13,7 @@ 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(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::MinSum, false));
-        png.raw.filter_image(RowFilter::MinSum, false);
-    });
 }
 
 #[bench]
@@ -23,9 +21,7 @@ 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(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::Entropy, false));
-        png.raw.filter_image(RowFilter::Entropy, false);
-    });
 }
 
 #[bench]
@@ -33,9 +29,7 @@ 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(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::Bigrams, false));
-        png.raw.filter_image(RowFilter::Bigrams, false);
-    });
 }
 
 #[bench]
@@ -43,9 +37,7 @@ 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(|| {
+    b.iter(|| png.raw.filter_image(FilterStrategy::BigEnt, false));
-        png.raw.filter_image(RowFilter::BigEnt, false);
-    });
 }
 
 #[bench]
@@ -54,6 +46,12 @@ fn filters_brute(b: &mut Bencher) {
     let png = PngData::new(&input, &Options::default()).unwrap();
 
     b.iter(|| {
-        png.raw.filter_image(RowFilter::Brute, false);
+        png.raw.filter_image(
+            FilterStrategy::Brute {
+                num_lines: 4,
+                level: 1,
+            },
+            false,
+        )
     });
 }

benches/zopfli.rs

@@ -3,21 +3,18 @@
 extern crate oxipng;
 extern crate test;
 
-use std::{num::NonZeroU8, path::PathBuf};
+use std::path::PathBuf;
 
 use oxipng::{internal_tests::*, *};
 use test::Bencher;
 
-// SAFETY: trivially safe. Stopgap solution until const unwrap is stabilized.
-const DEFAULT_ZOPFLI_ITERATIONS: NonZeroU8 = unsafe { NonZeroU8::new_unchecked(15) };
-
 #[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();
 
     b.iter(|| {
-        zopfli_deflate(png.raw.data.as_ref(), DEFAULT_ZOPFLI_ITERATIONS).ok();
+        zopfli_deflate(png.raw.data.as_ref(), ZopfliOptions::default()).ok();
     });
 }
 
@@ -27,7 +24,7 @@ fn zopfli_8_bits_strategy_0(b: &mut Bencher) {
     let png = PngData::new(&input, &Options::default()).unwrap();
 
     b.iter(|| {
-        zopfli_deflate(png.raw.data.as_ref(), DEFAULT_ZOPFLI_ITERATIONS).ok();
+        zopfli_deflate(png.raw.data.as_ref(), ZopfliOptions::default()).ok();
     });
 }
 
@@ -39,7 +36,7 @@ fn zopfli_4_bits_strategy_0(b: &mut Bencher) {
     let png = PngData::new(&input, &Options::default()).unwrap();
 
     b.iter(|| {
-        zopfli_deflate(png.raw.data.as_ref(), DEFAULT_ZOPFLI_ITERATIONS).ok();
+        zopfli_deflate(png.raw.data.as_ref(), ZopfliOptions::default()).ok();
     });
 }
 
@@ -51,7 +48,7 @@ fn zopfli_2_bits_strategy_0(b: &mut Bencher) {
     let png = PngData::new(&input, &Options::default()).unwrap();
 
     b.iter(|| {
-        zopfli_deflate(png.raw.data.as_ref(), DEFAULT_ZOPFLI_ITERATIONS).ok();
+        zopfli_deflate(png.raw.data.as_ref(), ZopfliOptions::default()).ok();
     });
 }
 
@@ -63,6 +60,6 @@ fn zopfli_1_bits_strategy_0(b: &mut Bencher) {
     let png = PngData::new(&input, &Options::default()).unwrap();
 
     b.iter(|| {
-        zopfli_deflate(png.raw.data.as_ref(), DEFAULT_ZOPFLI_ITERATIONS).ok();
+        zopfli_deflate(png.raw.data.as_ref(), ZopfliOptions::default()).ok();
     });
 }

build.rs

@@ -1,40 +0,0 @@
-use std::{
-    env,
-    fs::File,
-    io::{BufWriter, Error},
-    path::Path,
-};
-
-use clap_mangen::Man;
-
-include!("src/cli.rs");
-
-fn build_manpages(outdir: &Path) -> Result<(), Error> {
-    let app = build_command();
-
-    let file = Path::new(&outdir).join("oxipng.1");
-    let mut file = BufWriter::new(File::create(file)?);
-
-    Man::new(app).render(&mut file)?;
-
-    Ok(())
-}
-
-fn main() -> Result<(), Error> {
-    println!("cargo:rerun-if-changed=src/cli.rs");
-    println!("cargo:rerun-if-changed=src/display_chunks.rs");
-
-    // Create `target/<debug|release>/assets/` folder.
-    let outdir = match env::var_os("OUT_DIR") {
-        None => return Ok(()),
-        Some(outdir) => outdir,
-    };
-    let out_path = PathBuf::from(outdir);
-    let mut path = out_path.ancestors().nth(3).unwrap().to_owned();
-    path.push("assets");
-    std::fs::create_dir_all(&path).unwrap();
-
-    build_manpages(&path)?;
-
-    Ok(())
-}

scripts/manual.sh

@@ -1,5 +1,6 @@
-#!/bin/bash
+#!/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

src/apng.rs

@@ -0,0 +1,72 @@
+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

@@ -6,6 +6,7 @@ pub struct AtomicMin {
 }
 
 impl AtomicMin {
+    #[must_use]
     pub fn new(init: Option<usize>) -> Self {
         Self {
             val: AtomicUsize::new(init.unwrap_or(usize::MAX)),
@@ -14,16 +15,7 @@ impl AtomicMin {
 
     pub fn get(&self) -> Option<usize> {
         let val = self.val.load(SeqCst);
-        if val == usize::MAX {
+        if val == usize::MAX { None } else { Some(val) }
-            None
-        } else {
-            Some(val)
-        }
-    }
-
-    /// Unset value is usize_max
-    pub fn as_atomic_usize(&self) -> &AtomicUsize {
-        &self.val
     }
 
     /// Try a new value, returning true if it is the new minimum

src/cli.rs

@@ -1,9 +1,18 @@
-use std::path::PathBuf;
+use std::{num::NonZeroU64, path::PathBuf};
 
-use clap::{value_parser, Arg, ArgAction, Command};
+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,
@@ -14,6 +23,7 @@ pub fn build_command() -> Command {
         .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)")
@@ -31,14 +41,14 @@ Set the optimization level preset. The default level 2 is quite fast and provide
 compression. Lower levels are faster, higher levels provide better compression, though \
 with increasingly diminishing returns.
 
-    0   => --zc 5 --fast               (1 trial, determined heuristically)
+    0   => --zc 5  --fast              (filter chosen heuristically)
-    1   => --zc 10 --fast              (1 trial, determined heuristically)
+    1   => --zc 10 --fast              (filter chosen heuristically)
-    2   => --zc 11 -f 0,1,6,7 --fast   (4 fast trials, 1 main trial)
+    2   => --zc 11 -f 0,1,6,7 --fast
-    3   => --zc 11 -f 0,7,8,9          (4 trials)
+    3   => --zc 11 -f 0,7,8,9         --brute-level 1 --brute-lines 3
-    4   => --zc 12 -f 0,7,8,9          (4 trials)
+    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  (8 trials)
+    5   => --zc 12 -f 0,1,2,5,6,7,8,9 --brute-level 4 --brute-lines 4
-    6   => --zc 12 -f 0-9              (10 trials)
+    6   => --zc 12 -f 0-9             --brute-level 5 --brute-lines 8
-    max =>                             (stable alias for the max level)
+    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.")
@@ -49,14 +59,6 @@ preset, regardless of the order you write the arguments.")
                 .value_parser(["0", "1", "2", "3", "4", "5", "6", "max"])
                 .hide_possible_values(true),
         )
-        .arg(
-            Arg::new("backup")
-                .help("Back up modified files")
-                .short('b')
-                .long("backup")
-                .hide(true)
-                .action(ArgAction::SetTrue),
-        )
         .arg(
             Arg::new("recursive")
                 .help("Recurse input directories, optimizing all PNG files")
@@ -105,10 +107,10 @@ Note that this will not preserve the directory structure of the input files when
                 .action(ArgAction::SetTrue),
         )
         .arg(
-            Arg::new("pretend")
+            Arg::new("dry-run")
                 .help("Do not write any files, only show compression results")
-                .short('P')
+                .short('d')
-                .long("pretend")
+                .long("dry-run")
                 .action(ArgAction::SetTrue),
         )
         .arg(
@@ -131,10 +133,14 @@ Strip metadata chunks, where <mode> is one of:
 
 CAUTION: 'all' will convert APNGs to standard PNGs.
 
-Note that 'bKGD', 'sBIT' and 'hIST' will be forcibly stripped if the color type or bit \
+Please note that regardless of any options set, some chunks will necessarily be stripped \
-depth is changed, regardless of any options set.
+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 metadata.",
+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))
@@ -172,21 +178,22 @@ transformation and may be unsuitable for some applications.")
         )
         .arg(
             Arg::new("interlace")
-                .help("Set PNG interlacing type (0, 1, keep)")
+                .help("Set PNG interlacing (off, on, keep)")
                 .long_help("\
-Set the PNG interlacing type, where <type> is one of:
+Set the PNG interlacing mode, where <mode> is one of:
 
-    0     =>  Remove interlacing from all images that are processed
+    off   =>  Remove interlacing from all images that are processed
-    1     =>  Apply Adam7 interlacing on all images that are processed
+    on    =>  Apply Adam7 interlacing on all images that are processed
-    keep  =>  Keep the existing interlacing type of each image
+    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("type")
+                .value_name("mode")
-                .default_value("0")
+                .value_parser(["off", "on", "keep", "0", "1"])
-                .value_parser(["0", "1", "keep"])
+                .default_value("off")
+                .default_value_if("no-reductions", ArgPredicate::IsPresent, "keep")
                 .hide_possible_values(true),
         )
         .arg(
@@ -205,7 +212,7 @@ losslessly.")
         )
         .arg(
             Arg::new("verbose")
-                .help("Run in verbose mode (use twice to increase verbosity)")
+                .help("Show per-file info (use multiple times for more detail)")
                 .short('v')
                 .long("verbose")
                 .action(ArgAction::Count)
@@ -213,12 +220,20 @@ losslessly.")
         )
         .arg(
             Arg::new("quiet")
-                .help("Run in quiet mode")
+                .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)")
@@ -235,9 +250,9 @@ PNG delta filters (apply the same filter to every line)
 
 Heuristic strategies (try to find the best delta filter for each line)
     5  =>  MinSum    Minimum sum of absolute differences
-    6  =>  Entropy   Highest Shannon entropy
+    6  =>  Entropy   Smallest Shannon entropy
     7  =>  Bigrams   Lowest count of distinct bigrams
-    8  =>  BigEnt    Highest Shannon entropy of bigrams
+    8  =>  BigEnt    Smallest Shannon entropy of bigrams
     9  =>  Brute     Smallest compressed size (slow)
 
 The default value depends on the optimization level preset.")
@@ -257,15 +272,15 @@ CPU cores.")
         )
         .arg(
             Arg::new("compression")
-                .help("Deflate compression level (1-12)")
+                .help("Deflate compression level (0-12)")
                 .long_help("\
-Deflate compression level (1-12) for main compression trials. The levels here are defined \
+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(1..=12)
+                .value_parser(0..=12)
                 .conflicts_with("zopfli"),
         )
         .arg(
@@ -283,6 +298,8 @@ The default value depends on the optimization level preset.")
         .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),
         )
@@ -315,7 +332,7 @@ compressed chunks (such as iCCP) will also be disabled. Note that the combinatio
                 .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.")
+be processed successfully. The output will always have correct checksums.")
                 .long("fix")
                 .action(ArgAction::SetTrue),
         )
@@ -331,10 +348,54 @@ be processed successfully.")
                 .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('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")
@@ -344,16 +405,46 @@ timeout before each transformation or compression trial, and will stop trying to
 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.")
-                .value_name("secs")
                 .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("Set number of threads to use [default: num CPU cores]")
+                .help("Number of threads to use [default: num logical CPUs]")
-                .long("threads")
+                .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

@@ -32,13 +32,11 @@ impl Display for ColorType {
     #[inline]
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
-            ColorType::Grayscale { .. } => Display::fmt("Grayscale", f),
+            Self::Grayscale { .. } => write!(f, "Grayscale"),
-            ColorType::RGB { .. } => Display::fmt("RGB", f),
+            Self::RGB { .. } => write!(f, "RGB"),
-            ColorType::Indexed { palette } => {
+            Self::Indexed { palette } => write!(f, "Indexed ({} colors)", palette.len()),
-                Display::fmt(&format!("Indexed ({} colors)", palette.len()), f)
+            Self::GrayscaleAlpha => write!(f, "Grayscale + Alpha"),
-            }
+            Self::RGBA => write!(f, "RGB + Alpha"),
-            ColorType::GrayscaleAlpha => Display::fmt("Grayscale + Alpha", f),
-            ColorType::RGBA => Display::fmt("RGB + Alpha", f),
         }
     }
 }
@@ -46,49 +44,47 @@ impl Display for ColorType {
 impl ColorType {
     /// Get the code used by the PNG specification to denote this color type
     #[inline]
-    pub fn png_header_code(&self) -> u8 {
+    #[must_use]
+    pub const fn png_header_code(&self) -> u8 {
         match self {
-            ColorType::Grayscale { .. } => 0,
+            Self::Grayscale { .. } => 0,
-            ColorType::RGB { .. } => 2,
+            Self::RGB { .. } => 2,
-            ColorType::Indexed { .. } => 3,
+            Self::Indexed { .. } => 3,
-            ColorType::GrayscaleAlpha => 4,
+            Self::GrayscaleAlpha => 4,
-            ColorType::RGBA => 6,
+            Self::RGBA => 6,
         }
     }
 
     #[inline]
-    pub(crate) fn channels_per_pixel(&self) -> u8 {
+    pub(crate) const fn channels_per_pixel(&self) -> u8 {
         match self {
-            ColorType::Grayscale { .. } | ColorType::Indexed { .. } => 1,
+            Self::Grayscale { .. } | Self::Indexed { .. } => 1,
-            ColorType::GrayscaleAlpha => 2,
+            Self::GrayscaleAlpha => 2,
-            ColorType::RGB { .. } => 3,
+            Self::RGB { .. } => 3,
-            ColorType::RGBA => 4,
+            Self::RGBA => 4,
         }
     }
 
     #[inline]
-    pub(crate) fn is_rgb(&self) -> bool {
+    pub(crate) const fn is_rgb(&self) -> bool {
-        matches!(self, ColorType::RGB { .. } | ColorType::RGBA)
+        matches!(self, Self::RGB { .. } | Self::RGBA)
     }
 
     #[inline]
-    pub(crate) fn is_gray(&self) -> bool {
+    pub(crate) const fn is_gray(&self) -> bool {
-        matches!(
+        matches!(self, Self::Grayscale { .. } | Self::GrayscaleAlpha)
-            self,
-            ColorType::Grayscale { .. } | ColorType::GrayscaleAlpha
-        )
     }
 
     #[inline]
-    pub(crate) fn has_alpha(&self) -> bool {
+    pub(crate) const fn has_alpha(&self) -> bool {
-        matches!(self, ColorType::GrayscaleAlpha | ColorType::RGBA)
+        matches!(self, Self::GrayscaleAlpha | Self::RGBA)
     }
 
     #[inline]
-    pub(crate) fn has_trns(&self) -> bool {
+    pub(crate) const fn has_trns(&self) -> bool {
         match self {
-            ColorType::Grayscale { transparent_shade } => transparent_shade.is_some(),
+            Self::Grayscale { transparent_shade } => transparent_shade.is_some(),
-            ColorType::RGB { transparent_color } => transparent_color.is_some(),
+            Self::RGB { transparent_color } => transparent_color.is_some(),
             _ => false,
         }
     }
@@ -120,7 +116,7 @@ impl TryFrom<u8> for BitDepth {
             4 => Ok(Self::Four),
             8 => Ok(Self::Eight),
             16 => Ok(Self::Sixteen),
-            _ => Err(PngError::new("Unexpected bit depth")),
+            _ => Err(PngError::InvalidData),
         }
     }
 }

src/deflate/deflater.rs

@@ -1,12 +1,10 @@
 use libdeflater::*;
 
-use crate::{atomicmin::AtomicMin, PngError, PngResult};
+use crate::{PngError, PngResult};
 
-pub fn deflate(data: &[u8], level: u8, max_size: &AtomicMin) -> PngResult<Vec<u8>> {
+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
+    let capacity = max_size.unwrap_or_else(|| compressor.zlib_compress_bound(data.len()));
-        .get()
-        .unwrap_or_else(|| compressor.zlib_compress_bound(data.len()));
     let mut dest = vec![0; capacity];
     let len = compressor
         .zlib_compress(data, &mut dest)
@@ -24,12 +22,13 @@ pub fn inflate(data: &[u8], out_size: usize) -> PngResult<Vec<u8>> {
         .zlib_decompress(data, &mut dest)
         .map_err(|err| match err {
             DecompressionError::BadData => PngError::InvalidData,
-            DecompressionError::InsufficientSpace => PngError::new("inflated data too long"),
+            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);

src/deflate/mod.rs

@@ -1,42 +1,38 @@
 mod deflater;
-#[cfg(feature = "zopfli")]
-use std::num::NonZeroU8;
 use std::{fmt, fmt::Display};
 
 pub use deflater::{crc32, deflate, inflate};
 
-use crate::{AtomicMin, PngError, PngResult};
+use crate::{PngError, PngResult};
+
 #[cfg(feature = "zopfli")]
 mod zopfli_oxipng;
 #[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)]
-/// DEFLATE algorithms supported by oxipng
+pub enum Deflater {
-pub enum Deflaters {
     /// Use libdeflater.
     Libdeflater {
-        /// Which compression level to use on the file (1-12)
+        /// Which compression level to use on the file (0-12)
         compression: u8,
     },
     #[cfg(feature = "zopfli")]
     /// Use the better but slower Zopfli implementation
-    Zopfli {
+    Zopfli(ZopfliOptions),
-        /// The number of compression iterations to do. 15 iterations are fine
-        /// for small files, but bigger files will need to be compressed with
-        /// less iterations, or else they will be too slow.
-        iterations: NonZeroU8,
-    },
 }
 
-impl Deflaters {
+impl Deflater {
-    pub(crate) fn deflate(self, data: &[u8], max_size: &AtomicMin) -> PngResult<Vec<u8>> {
+    pub(crate) fn deflate(self, data: &[u8], max_size: Option<usize>) -> PngResult<Vec<u8>> {
         let compressed = match self {
             Self::Libdeflater { compression } => deflate(data, compression, max_size)?,
             #[cfg(feature = "zopfli")]
-            Self::Zopfli { iterations } => zopfli_deflate(data, iterations)?,
+            Self::Zopfli(options) => zopfli_deflate(data, options)?,
         };
-        if let Some(max) = max_size.get() {
+        if let Some(max) = max_size {
             if compressed.len() > max {
                 return Err(PngError::DeflatedDataTooLong(max));
             }
@@ -45,13 +41,13 @@ impl Deflaters {
     }
 }
 
-impl Display for Deflaters {
+impl Display for Deflater {
     #[inline]
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
-            Self::Libdeflater { compression } => Display::fmt(compression, f),
+            Self::Libdeflater { compression } => write!(f, "zc = {compression}"),
             #[cfg(feature = "zopfli")]
-            Self::Zopfli { .. } => Display::fmt("zopfli", f),
+            Self::Zopfli(options) => write!(f, "zopfli, zi = {}", options.iteration_count),
         }
     }
 }

src/deflate/zopfli_oxipng.rs

@@ -1,17 +1,13 @@
-use std::num::NonZeroU8;
-
 use crate::{PngError, PngResult};
 
-pub fn deflate(data: &[u8], iterations: NonZeroU8) -> PngResult<Vec<u8>> {
+pub fn deflate(data: &[u8], options: zopfli::Options) -> PngResult<Vec<u8>> {
     let mut output = Vec::with_capacity(data.len());
-    let options = zopfli::Options {
+    // Since Rust v1.74, passing &[u8] directly into zopfli causes a regression in compressed size
-        iteration_count: iterations.into(),
+    // for some files. Wrapping the slice in another Read implementer such as Box fixes it for now.
-        ..Default::default()
+    match zopfli::compress(options, zopfli::Format::Zlib, Box::new(data), &mut output) {
-    };
+        Ok(()) => (),
-    match zopfli::compress(options, zopfli::Format::Zlib, data, &mut output) {
-        Ok(_) => (),
         Err(_) => return Err(PngError::new("Failed to compress in zopfli")),
-    };
+    }
     output.shrink_to_fit();
     Ok(output)
 }

src/error.rs

@@ -2,18 +2,22 @@ use std::{error::Error, fmt};
 
 use crate::colors::{BitDepth, ColorType};
 
-#[derive(Debug, Clone)]
+#[derive(Debug)]
 #[non_exhaustive]
 pub enum PngError {
-    DeflatedDataTooLong(usize),
+    APNGOutOfOrder,
-    TimedOut,
+    C2PAMetadataPreventsChanges,
-    NotPNG,
-    APNGNotSupported,
-    InvalidData,
-    TruncatedData,
     ChunkMissing(&'static str),
-    InvalidDepthForType(BitDepth, ColorType),
+    CRCMismatch([u8; 4]),
+    DeflatedDataTooLong(usize),
     IncorrectDataLength(usize, usize),
+    InflatedDataTooLong(usize),
+    InvalidData,
+    InvalidDepthForType(BitDepth, ColorType),
+    NotPNG,
+    ReadFailed(String, std::io::Error),
+    TruncatedData,
+    WriteFailed(String, std::io::Error),
     Other(Box<str>),
 }
 
@@ -24,31 +28,42 @@ impl fmt::Display for PngError {
     #[cold]
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
-            PngError::DeflatedDataTooLong(_) => f.write_str("deflated data too long"),
+            Self::APNGOutOfOrder => f.write_str("APNG chunks are out of order"),
-            PngError::TimedOut => f.write_str("timed out"),
+            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 => {
-                f.write_str("Missing data in the file; the file is truncated")
-            }
-            PngError::APNGNotSupported => f.write_str("APNG files are not (yet) supported"),
-            PngError::ChunkMissing(s) => write!(f, "Chunk {} missing or empty", s),
-            PngError::InvalidDepthForType(d, ref c) => {
-                write!(f, "Invalid bit depth {} for color type {}", d, c)
-            }
-            PngError::IncorrectDataLength(l1, l2) => write!(
-                f,
-                "Data length {} does not match the expected length {}",
-                l1, l2
             ),
-            PngError::Other(ref s) => f.write_str(s),
+            Self::ChunkMissing(s) => write!(f, "Chunk {s} missing or empty"),
+            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"),
+            Self::ReadFailed(ref s, ref e) => write!(f, "Failed to read from {s}: {e}"),
+            Self::TruncatedData => f.write_str("Missing data in the file; the file is truncated"),
+            Self::WriteFailed(ref s, ref e) => write!(f, "Failed to write to {s}: {e}"),
+            Self::Other(ref s) => f.write_str(s),
         }
     }
 }
 
 impl PngError {
     #[cold]
-    pub fn new(description: &str) -> PngError {
+    #[must_use]
-        PngError::Other(description.into())
+    pub fn new(description: &str) -> Self {
+        Self::Other(description.into())
     }
 }

src/evaluate.rs

@@ -4,37 +4,44 @@
 #[cfg(not(feature = "parallel"))]
 use std::cell::RefCell;
 use std::sync::{
-    atomic::{AtomicUsize, Ordering::*},
     Arc,
+    atomic::{AtomicUsize, Ordering::*},
 };
 
-#[cfg(feature = "parallel")]
+use deflate::Deflater;
-use crossbeam_channel::{unbounded, Receiver, Sender};
 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::{atomicmin::AtomicMin, deflate, filters::RowFilter, png::PngImage, Deadline, PngError};
+use crate::{
+    Deadline, PngError, atomicmin::AtomicMin, deflate, filters::FilterStrategy, png::PngImage,
+};
 
-pub struct Candidate {
+pub(crate) struct Candidate {
     pub image: Arc<PngImage>,
-    pub idat_data: Vec<u8>,
+    pub idat_data: Option<Vec<u8>>,
-    pub filtered: Vec<u8>,
+    pub estimated_output_size: usize,
-    pub filter: RowFilter,
+    /// The input filter, which is retained for printing and for APNG frames.
-    // first wins tie-breaker
+    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 {
+    fn cmp_key(&self) -> impl Ord + use<> {
         (
-            self.idat_data.len() + self.image.key_chunks_size(),
+            self.estimated_output_size,
             self.image.data.len(),
-            self.image.ihdr.bit_depth,
+            self.filter.clone(),
-            self.filter,
+            // Prefer the later image added (e.g. baseline, which is always added last)
-            self.nth,
+            usize::MAX - self.nth,
         )
     }
 }
@@ -42,9 +49,10 @@ impl Candidate {
 /// Collect image versions and pick one that compresses best
 pub(crate) struct Evaluator {
     deadline: Arc<Deadline>,
-    filters: IndexSet<RowFilter>,
+    filters: IndexSet<FilterStrategy>,
-    compression: u8,
+    deflater: Deflater,
     optimize_alpha: bool,
+    final_round: bool,
     nth: AtomicUsize,
     executed: Arc<AtomicUsize>,
     best_candidate_size: Arc<AtomicMin>,
@@ -59,17 +67,19 @@ pub(crate) struct Evaluator {
 impl Evaluator {
     pub fn new(
         deadline: Arc<Deadline>,
-        filters: IndexSet<RowFilter>,
+        filters: IndexSet<FilterStrategy>,
-        compression: u8,
+        deflater: Deflater,
         optimize_alpha: bool,
+        final_round: bool,
     ) -> Self {
         #[cfg(feature = "parallel")]
-        let eval_channel = unbounded();
+        let eval_channel = channel();
         Self {
             deadline,
             filters,
-            compression,
+            deflater,
             optimize_alpha,
+            final_round,
             nth: AtomicUsize::new(0),
             executed: Arc::new(AtomicUsize::new(0)),
             best_candidate_size: Arc::new(AtomicMin::new(None)),
@@ -108,7 +118,7 @@ impl Evaluator {
 
     /// Check if the image is smaller than others
     pub fn try_image(&self, image: Arc<PngImage>) {
-        let description = format!("{}", image.ihdr.color_type);
+        let description = image.ihdr.color_type.to_string();
         self.try_image_with_description(image, &description);
     }
 
@@ -118,8 +128,9 @@ impl Evaluator {
         // These clones are only cheap refcounts
         let deadline = self.deadline.clone();
         let filters = self.filters.clone();
-        let compression = self.compression;
+        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();
@@ -135,29 +146,37 @@ impl Evaluator {
             // 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| {
+            filters_iter.for_each(|filter| {
                 if deadline.passed() {
                     return;
                 }
-                let filtered = image.filter_image(filter, optimize_alpha);
+                let (filtered, filter_used) = image.filter_image(filter.clone(), optimize_alpha);
-                let idat_data = deflate::deflate(&filtered, compression, &best_candidate_size);
+                let idat_data = deflater.deflate(&filtered, best_candidate_size.get());
                 if let Ok(idat_data) = idat_data {
-                    let size = idat_data.len() + image.key_chunks_size();
+                    let estimated_output_size = image.estimated_output_size(&idat_data);
-                    best_candidate_size.set_min(size);
                     trace!(
                         "Eval: {}-bit {:23} {:8}   {} bytes",
-                        image.ihdr.bit_depth,
+                        image.ihdr.bit_depth, description, filter, estimated_output_size
-                        description,
-                        filter,
-                        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,
+                        idat_data: if final_round { Some(idat_data) } else { None },
-                        filtered,
+                        estimated_output_size,
-                        filter,
+                        filter: filter.clone(),
+                        filter_used,
                         nth,
                     };
+                    best_candidate_size.set_min(estimated_output_size);
 
                     #[cfg(feature = "parallel")]
                     {
@@ -174,10 +193,7 @@ impl Evaluator {
                 } else if let Err(PngError::DeflatedDataTooLong(size)) = idat_data {
                     trace!(
                         "Eval: {}-bit {:23} {:8}  >{} bytes",
-                        image.ihdr.bit_depth,
+                        image.ihdr.bit_depth, description, filter, size
-                        description,
-                        filter,
-                        size
                     );
                 }
             });

src/filters.rs

@@ -1,29 +1,67 @@
 use std::{fmt, fmt::Display, mem::transmute};
 
-use crate::error::PngError;
+/// Filtering strategy for use in [`Options`][crate::Options]
+#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone, Hash)]
+pub enum FilterStrategy {
+    /// 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),
+        }
+    }
+}
+
+/// PNG delta filters
 #[repr(u8)]
 #[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Hash)]
 pub enum RowFilter {
-    // Standard filter types
     None,
     Sub,
     Up,
     Average,
     Paeth,
-    // Heuristic strategies
-    MinSum,
-    Entropy,
-    Bigrams,
-    BigEnt,
-    Brute,
 }
 
 impl TryFrom<u8> for RowFilter {
     type Error = ();
 
     fn try_from(value: u8) -> Result<Self, Self::Error> {
-        if value > Self::LAST {
+        if value > 4 {
             return Err(());
         }
         unsafe { transmute(value as i8) }
@@ -39,11 +77,6 @@ impl Display for RowFilter {
                 Self::Up => "Up",
                 Self::Average => "Average",
                 Self::Paeth => "Paeth",
-                Self::MinSum => "MinSum",
-                Self::Entropy => "Entropy",
-                Self::Bigrams => "Bigrams",
-                Self::BigEnt => "BigEnt",
-                Self::Brute => "Brute",
             },
             f,
         )
@@ -51,9 +84,7 @@ impl Display for RowFilter {
 }
 
 impl RowFilter {
-    pub const LAST: u8 = Self::Brute as u8;
+    pub(crate) const ALL: [Self; 5] = [Self::None, Self::Sub, Self::Up, Self::Average, Self::Paeth];
-    pub(crate) const STANDARD: [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(
@@ -96,25 +127,20 @@ impl RowFilter {
             }
             Self::Average => {
                 for (i, byte) in data.iter().enumerate() {
-                    buf.push(match i.checked_sub(bpp) {
+                    buf.push(byte.wrapping_sub(i.checked_sub(bpp).map_or_else(
-                        Some(x) => byte.wrapping_sub(
+                        || prev_line[i] >> 1,
-                            ((u16::from(data[x]) + u16::from(prev_line[i])) >> 1) as u8,
+                        |x| ((u16::from(data[x]) + u16::from(prev_line[i])) >> 1) as u8,
-                        ),
+                    )));
-                        None => byte.wrapping_sub(prev_line[i] >> 1),
-                    });
                 }
             }
             Self::Paeth => {
                 for (i, byte) in data.iter().enumerate() {
-                    buf.push(match i.checked_sub(bpp) {
+                    buf.push(byte.wrapping_sub(i.checked_sub(bpp).map_or_else(
-                        Some(x) => {
+                        || prev_line[i],
-                            byte.wrapping_sub(paeth_predictor(data[x], prev_line[i], prev_line[x]))
+                        |x| paeth_predictor(data[x], prev_line[i], prev_line[x]),
-                        }
+                    )));
-                        None => byte.wrapping_sub(prev_line[i]),
-                    });
                 }
             }
-            _ => unreachable!(),
         }
     }
 
@@ -125,8 +151,8 @@ impl RowFilter {
             return;
         }
 
-        let mut pixels: Vec<_> = data.chunks_mut(bpp).collect();
+        let mut pixels: Vec<_> = data.chunks_exact_mut(bpp).collect();
-        let prev_pixels: Vec<_> = prev_line.chunks(bpp).collect();
+        let prev_pixels: Vec<_> = prev_line.chunks_exact(bpp).collect();
         for i in 0..pixels.len() {
             if pixels[i].iter().skip(color_bytes).all(|b| *b == 0) {
                 // If the first pixel in the row is transparent, find the next non-transparent pixel and pretend
@@ -138,10 +164,28 @@ impl RowFilter {
                         .unwrap_or(i),
                     _ => 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 => {
-                        for j in 0..color_bytes {
+                        // The code below is roughly equivalent to pixels[i][0..color_bytes].copy_from_slice(&pixels[prev][0..color_bytes]),
-                            pixels[i][j] = pixels[prev][j];
+                        // 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 => {
@@ -170,7 +214,6 @@ impl RowFilter {
                             };
                         }
                     }
-                    _ => unreachable!(),
                 }
             }
         }
@@ -182,7 +225,7 @@ impl RowFilter {
         data: &[u8],
         prev_line: &[u8],
         buf: &mut Vec<u8>,
-    ) -> Result<(), PngError> {
+    ) {
         buf.clear();
         buf.reserve(data.len());
         assert!(data.len() >= bpp);
@@ -194,10 +237,7 @@ impl RowFilter {
             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(match prev_byte {
+                    buf.push(prev_byte.map_or(cur, |b| cur.wrapping_add(b)));
-                        Some(b) => cur.wrapping_add(b),
-                        None => cur,
-                    });
                 }
             }
             Self::Up => {
@@ -210,10 +250,10 @@ impl RowFilter {
             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(match prev_byte {
+                    buf.push(cur.wrapping_add(prev_byte.map_or_else(
-                        Some(b) => cur.wrapping_add(((u16::from(b) + u16::from(last)) >> 1) as u8),
+                        || last >> 1,
-                        None => cur.wrapping_add(last >> 1),
+                        |b| ((u16::from(b) + u16::from(last)) >> 1) as u8,
-                    });
+                    )));
                 }
             }
             Self::Paeth => {
@@ -231,9 +271,7 @@ impl RowFilter {
                     );
                 }
             }
-            _ => return Err(PngError::InvalidData),
         }
-        Ok(())
     }
 }
 

src/headers.rs

@@ -1,14 +1,13 @@
 use indexmap::IndexSet;
-use log::warn;
+use log::{debug, trace, warn};
 use rgb::{RGB16, RGBA8};
 
 use crate::{
+    Deflater, Options, PngResult,
     colors::{BitDepth, ColorType},
     deflate::{crc32, inflate},
     display_chunks::DISPLAY_CHUNKS,
     error::PngError,
-    interlace::Interlacing,
-    AtomicMin, Deflaters, PngResult,
 };
 
 #[derive(Debug, Clone)]
@@ -22,32 +21,30 @@ pub struct IhdrData {
     pub color_type: ColorType,
     /// The bit depth of the image
     pub bit_depth: BitDepth,
-    /// The interlacing mode of the image
+    /// Whether the image is interlaced
-    pub interlaced: Interlacing,
+    pub interlaced: bool,
 }
 
 impl IhdrData {
     /// Bits per pixel
     #[must_use]
     #[inline]
-    pub fn bpp(&self) -> usize {
+    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 fn raw_data_size(&self) -> usize {
+    pub const fn raw_data_size(&self) -> usize {
         let w = self.width as usize;
         let h = self.height as usize;
         let bpp = self.bpp();
 
-        fn bitmap_size(bpp: usize, w: usize, h: usize) -> usize {
+        const fn bitmap_size(bpp: usize, w: usize, h: usize) -> usize {
-            ((w * bpp + 7) / 8) * h
+            (w * bpp).div_ceil(8) * h
         }
 
-        if self.interlaced == Interlacing::None {
+        if self.interlaced {
-            bitmap_size(bpp, w, h) + h
-        } else {
             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);
@@ -61,6 +58,8 @@ impl IhdrData {
                 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
         }
     }
 }
@@ -71,10 +70,12 @@ pub struct Chunk {
     pub data: Vec<u8>,
 }
 
+/// [`Options`][crate::Options] to use when stripping chunks (metadata)
 #[derive(Debug, PartialEq, Eq, Clone)]
-/// Options to use when stripping chunks
 pub enum StripChunks {
     /// None
+    ///
+    /// ...except caBX chunk if it contains a C2PA.org signature.
     None,
     /// Remove specific chunks
     Strip(IndexSet<[u8; 4]>),
@@ -89,11 +90,11 @@ pub enum StripChunks {
 impl StripChunks {
     pub(crate) fn keep(&self, name: &[u8; 4]) -> bool {
         match &self {
-            StripChunks::None => true,
+            Self::None => true,
-            StripChunks::Keep(names) => names.contains(name),
+            Self::Keep(names) => names.contains(name),
-            StripChunks::Strip(names) => !names.contains(name),
+            Self::Strip(names) => !names.contains(name),
-            StripChunks::Safe => DISPLAY_CHUNKS.contains(name),
+            Self::Safe => DISPLAY_CHUNKS.contains(name),
-            StripChunks::All => false,
+            Self::All => false,
         }
     }
 }
@@ -111,6 +112,36 @@ pub struct RawChunk<'a> {
     pub data: &'a [u8],
 }
 
+impl RawChunk<'_> {
+    // 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,
@@ -121,37 +152,27 @@ pub fn parse_next_chunk<'a>(
             .get(*byte_offset..*byte_offset + 4)
             .ok_or(PngError::TruncatedData)?,
     );
+    if byte_data.len() < *byte_offset + 12 + length as usize {
+        return Err(PngError::TruncatedData);
+    }
     *byte_offset += 4;
 
     let chunk_start = *byte_offset;
-    let chunk_name = byte_data
+    let chunk_name = &byte_data[chunk_start..chunk_start + 4];
-        .get(chunk_start..chunk_start + 4)
-        .ok_or(PngError::TruncatedData)?;
     if chunk_name == b"IEND" {
         // End of data
         return Ok(None);
     }
     *byte_offset += 4;
 
-    let data = byte_data
+    let data = &byte_data[*byte_offset..*byte_offset + length as usize];
-        .get(*byte_offset..*byte_offset + length as usize)
-        .ok_or(PngError::TruncatedData)?;
     *byte_offset += length as usize;
-    let crc = read_be_u32(
+    let crc = read_be_u32(&byte_data[*byte_offset..*byte_offset + 4]);
-        byte_data
-            .get(*byte_offset..*byte_offset + 4)
-            .ok_or(PngError::TruncatedData)?,
-    );
     *byte_offset += 4;
 
-    let chunk_bytes = byte_data
+    let chunk_bytes = &byte_data[chunk_start..chunk_start + 4 + length as usize];
-        .get(chunk_start..chunk_start + 4 + length as usize)
-        .ok_or(PngError::TruncatedData)?;
     if !fix_errors && crc32(chunk_bytes) != crc {
-        return Err(PngError::new(&format!(
+        return Err(PngError::CRCMismatch(chunk_name.try_into().unwrap()));
-            "CRC Mismatch in {} chunk; May be recoverable by using --fix",
-            String::from_utf8_lossy(chunk_name)
-        )));
     }
 
     let name: [u8; 4] = chunk_name.try_into().unwrap();
@@ -170,13 +191,13 @@ pub fn parse_ihdr_chunk(
             0 => ColorType::Grayscale {
                 transparent_shade: trns_data
                     .filter(|t| t.len() >= 2)
-                    .map(|t| u16::from_be_bytes([t[0], t[1]])),
+                    .map(|t| read_be_u16(&t[0..2])),
             },
             2 => ColorType::RGB {
                 transparent_color: trns_data.filter(|t| t.len() >= 6).map(|t| RGB16 {
-                    r: u16::from_be_bytes([t[0], t[1]]),
+                    r: read_be_u16(&t[0..2]),
-                    g: u16::from_be_bytes([t[2], t[3]]),
+                    g: read_be_u16(&t[2..4]),
-                    b: u16::from_be_bytes([t[4], t[5]]),
+                    b: read_be_u16(&t[4..6]),
                 }),
             },
             3 => ColorType::Indexed {
@@ -184,12 +205,16 @@ pub fn parse_ihdr_chunk(
             },
             4 => ColorType::GrayscaleAlpha,
             6 => ColorType::RGBA,
-            _ => return Err(PngError::new("Unexpected color type in header")),
+            _ => return Err(PngError::InvalidData),
         },
         bit_depth: byte_data[8].try_into()?,
         width: read_be_u32(&byte_data[0..4]),
         height: read_be_u32(&byte_data[4..8]),
-        interlaced: interlaced.try_into()?,
+        interlaced: match interlaced {
+            0 => false,
+            1 => true,
+            _ => return Err(PngError::InvalidData),
+        },
     })
 }
 
@@ -198,9 +223,9 @@ 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_else(|| PngError::new("no palette in indexed image"))?;
+    let palette_data = palette_data.ok_or(PngError::ChunkMissing("PLTE"))?;
     let mut palette: Vec<_> = palette_data
-        .chunks(3)
+        .chunks_exact(3)
         .map(|color| RGBA8::new(color[0], color[1], color[2], 255))
         .collect();
 
@@ -213,12 +238,17 @@ fn palette_to_rgba(
 }
 
 #[inline]
-fn read_be_u32(bytes: &[u8]) -> u32 {
+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) -> Option<Vec<u8>> {
+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 {
@@ -233,21 +263,24 @@ pub fn extract_icc(iccp: &Chunk) -> Option<Vec<u8>> {
     if compression_method != 0 {
         return None; // The profile is supposed to be compressed (method 0)
     }
-    // The decompressed size is unknown so we have to guess the required buffer size
+    // Libdeflate works with a fixed size buffer. Since the decompressed size is unknown we have to
-    let max_size = compressed_data.len() * 2 + 1000;
+    // guess the required buffer size. We allow a fairly generous 10x factor with a minimum of 1000.
-    match inflate(compressed_data, max_size) {
+    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);
+            warn!("Failed to decompress icc: {e}");
             None
         }
     }
 }
 
-/// Construct an iCCP chunk by compressing the ICC profile
+/// Make an iCCP chunk by compressing the ICC profile
-pub fn construct_iccp(icc: &[u8], deflater: Deflaters) -> PngResult<Chunk> {
+pub fn make_iccp(icc: &[u8], deflater: Deflater, max_size: Option<usize>) -> PngResult<Chunk> {
-    let mut compressed = deflater.deflate(icc, &AtomicMin::new(None))?;
+    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
@@ -284,3 +317,109 @@ pub fn srgb_rendering_intent(icc_data: &[u8]) -> Option<u8> {
         _ => 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

@@ -1,39 +1,6 @@
-use std::{fmt, fmt::Display};
-
 use bitvec::prelude::*;
 
-use crate::{headers::IhdrData, png::PngImage, PngError};
+use crate::{headers::IhdrData, png::PngImage};
-
-#[repr(u8)]
-#[derive(Debug, PartialEq, Eq, Clone, Copy)]
-pub enum Interlacing {
-    None,
-    Adam7,
-}
-
-impl TryFrom<u8> for Interlacing {
-    type Error = PngError;
-
-    fn try_from(value: u8) -> Result<Self, Self::Error> {
-        match value {
-            0 => Ok(Self::None),
-            1 => Ok(Self::Adam7),
-            _ => Err(PngError::new("Unexpected interlacing in header")),
-        }
-    }
-}
-
-impl Display for Interlacing {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        Display::fmt(
-            match self {
-                Self::None => "non-interlaced",
-                Self::Adam7 => "interlaced",
-            },
-            f,
-        )
-    }
-}
 
 #[must_use]
 pub fn interlace_image(png: &PngImage) -> PngImage {
@@ -86,7 +53,7 @@ pub fn interlace_image(png: &PngImage) -> PngImage {
         data: output,
         ihdr: IhdrData {
             color_type: png.ihdr.color_type.clone(),
-            interlaced: Interlacing::Adam7,
+            interlaced: true,
             ..png.ihdr
         },
     }
@@ -100,7 +67,7 @@ pub fn deinterlace_image(png: &PngImage) -> PngImage {
         },
         ihdr: IhdrData {
             color_type: png.ihdr.color_type.clone(),
-            interlaced: Interlacing::None,
+            interlaced: false,
             ..png.ihdr
         },
     }
@@ -118,10 +85,8 @@ fn deinterlace_bits(png: &PngImage) -> Vec<u8> {
     let mut current_y: usize = pass_constants.y_shift as usize;
     for line in png.scan_lines(false) {
         let bit_vec = line.data.view_bits::<Msb0>();
-        let bits_in_line = ((png.ihdr.width - u32::from(pass_constants.x_shift)
+        let bits_in_line = (png.ihdr.width - u32::from(pass_constants.x_shift))
-            + u32::from(pass_constants.x_step)
+            .div_ceil(u32::from(pass_constants.x_step)) as usize
-            - 1)
-            / u32::from(pass_constants.x_step)) as usize
             * bits_per_pixel;
         for (i, bit) in bit_vec.iter().by_vals().enumerate() {
             // Avoid moving padded 0's into new image
@@ -184,7 +149,7 @@ fn deinterlace_bytes(png: &PngImage) -> Vec<u8> {
     lines.concat()
 }
 
-fn increment_pass(current_pass: &mut u8, ihdr: &IhdrData) -> bool {
+const fn increment_pass(current_pass: &mut u8, ihdr: &IhdrData) -> bool {
     if *current_pass == 7 {
         return false;
     }

src/lib.rs

@@ -1,23 +1,4 @@
-#![warn(trivial_casts, trivial_numeric_casts, unused_import_braces)]
+#![cfg_attr(not(feature = "zopfli"), allow(unreachable_patterns))]
-#![deny(missing_debug_implementations, missing_copy_implementations)]
-#![warn(clippy::expl_impl_clone_on_copy)]
-#![warn(clippy::float_cmp_const)]
-#![warn(clippy::linkedlist)]
-#![warn(clippy::map_flatten)]
-#![warn(clippy::match_same_arms)]
-#![warn(clippy::mem_forget)]
-#![warn(clippy::mut_mut)]
-#![warn(clippy::mutex_integer)]
-#![warn(clippy::needless_continue)]
-#![warn(clippy::path_buf_push_overwrite)]
-#![warn(clippy::range_plus_one)]
-#![allow(clippy::cognitive_complexity)]
-#![allow(clippy::upper_case_acronyms)]
-#![cfg_attr(
-    not(feature = "zopfli"),
-    allow(irrefutable_let_patterns),
-    allow(unreachable_patterns)
-)]
 
 #[cfg(feature = "parallel")]
 extern crate rayon;
@@ -26,39 +7,39 @@ extern crate rayon;
 mod rayon;
 
 use std::{
-    borrow::Cow,
+    fs::File,
-    fs::{File, Metadata},
+    io::{BufWriter, Read, Write, stdin, stdout},
-    io::{stdin, stdout, BufWriter, Read, Write},
+    path::PathBuf,
-    path::Path,
     sync::{
-        atomic::{AtomicBool, Ordering},
         Arc,
+        atomic::{AtomicBool, Ordering},
     },
     time::{Duration, Instant},
 };
 
-pub use indexmap::{indexset, IndexSet};
+pub use indexmap::{IndexSet, indexset};
 use log::{debug, info, trace, warn};
 use rayon::prelude::*;
 pub use rgb::{RGB16, RGBA8};
 
+#[cfg(feature = "zopfli")]
+pub use crate::deflate::ZopfliOptions;
+pub use crate::{
+    colors::{BitDepth, ColorType},
+    deflate::Deflater,
+    error::PngError,
+    filters::{FilterStrategy, RowFilter},
+    headers::StripChunks,
+    options::{InFile, Options, OutFile},
+};
 use crate::{
-    atomicmin::AtomicMin,
+    evaluate::{Candidate, Evaluator},
-    evaluate::Evaluator,
     headers::*,
     png::{PngData, PngImage},
     reduction::*,
 };
-pub use crate::{
-    colors::{BitDepth, ColorType},
-    deflate::Deflaters,
-    error::PngError,
-    filters::RowFilter,
-    headers::StripChunks,
-    interlace::Interlacing,
-    options::{InFile, Options, OutFile},
-};
 
+mod apng;
 mod atomicmin;
 mod colors;
 mod deflate;
@@ -79,10 +60,11 @@ mod sanity_checks;
 pub mod internal_tests {
     #[cfg(feature = "sanity-checks")]
     pub use crate::sanity_checks::*;
-    pub use crate::{atomicmin::*, deflate::*, png::*, reduction::*};
+    pub use crate::{deflate::*, png::*, reduction::*};
 }
 
 pub type PngResult<T> = Result<T, PngError>;
+pub type OptimizationResult = PngResult<(usize, usize)>;
 
 #[derive(Debug)]
 /// A raw image definition which can be used to create an optimized png
@@ -105,7 +87,7 @@ impl RawImage {
         color_type: ColorType,
         bit_depth: BitDepth,
         data: Vec<u8>,
-    ) -> Result<Self, PngError> {
+    ) -> PngResult<Self> {
         // Validate bit depth
         let valid_depth = match color_type {
             ColorType::Grayscale { .. } => true,
@@ -118,7 +100,7 @@ impl RawImage {
 
         // Validate data length
         let bpp = bit_depth as usize * color_type.channels_per_pixel() as usize;
-        let row_bytes = (bpp * width as usize + 7) / 8;
+        let row_bytes = (bpp * width as usize).div_ceil(8);
         let expected_len = row_bytes * height as usize;
         if data.len() != expected_len {
             return Err(PngError::IncorrectDataLength(data.len(), expected_len));
@@ -131,7 +113,7 @@ impl RawImage {
                     height,
                     color_type,
                     bit_depth,
-                    interlaced: Interlacing::None,
+                    interlaced: false,
                 },
                 data,
             }),
@@ -147,71 +129,56 @@ impl RawImage {
     /// Add an ICC profile for the image
     pub fn add_icc_profile(&mut self, data: &[u8]) {
         // Compress with fastest compression level - will be recompressed during optimization
-        let deflater = Deflaters::Libdeflater { compression: 1 };
+        let deflater = Deflater::Libdeflater { compression: 1 };
-        if let Ok(iccp) = construct_iccp(data, deflater) {
+        if let Ok(iccp) = make_iccp(data, deflater, None) {
             self.aux_chunks.push(iccp);
         }
     }
 
     /// Create an optimized png from the raw image data using the options provided
     pub fn create_optimized_png(&self, opts: &Options) -> PngResult<Vec<u8>> {
-        let deadline = Arc::new(Deadline::new(opts.timeout));
+        let mut opts = opts.to_owned();
-        let mut png = optimize_raw(self.png.clone(), opts, deadline.clone(), None)
+        let mut aux_chunks: Vec<_> = self
-            .ok_or_else(|| PngError::new("Failed to optimize input data"))?;
-
-        // Process aux chunks
-        png.aux_chunks = self
             .aux_chunks
             .iter()
             .filter(|c| opts.strip.keep(&c.name))
             .cloned()
             .collect();
-        postprocess_chunks(&mut png, opts, deadline, &self.png.ihdr);
+        preprocess_chunks(&mut aux_chunks, &mut opts);
+
+        let deadline = Arc::new(Deadline::new(opts.timeout));
+        let Some(result) = optimize_raw(self.png.clone(), &opts, deadline, None) else {
+            return Err(PngError::new("Failed to optimize input data"));
+        };
+
+        let mut png = PngData {
+            raw: result.image,
+            idat_data: result.idat_data.unwrap(),
+            aux_chunks,
+            frames: Vec::new(),
+        };
+        postprocess_chunks(&mut png.aux_chunks, &png.raw.ihdr, &self.png.ihdr);
 
         Ok(png.output())
     }
 }
 
 /// Perform optimization on the input file using the options provided
-pub fn optimize(input: &InFile, output: &OutFile, opts: &Options) -> PngResult<()> {
+///
+/// Returns the original and optimized file sizes
+pub fn optimize(input: &InFile, output: &OutFile, opts: &Options) -> OptimizationResult {
     // Read in the file and try to decode as PNG.
-    info!("Processing: {}", input);
+    info!("Processing: {input}");
 
     let deadline = Arc::new(Deadline::new(opts.timeout));
 
-    // grab metadata before even opening input file to preserve atime
-    let opt_metadata_preserved;
     let in_data = match *input {
-        InFile::Path(ref input_path) => {
+        InFile::Path(ref input_path) => PngData::read_file(input_path)?,
-            if matches!(
-                output,
-                OutFile::Path {
-                    preserve_attrs: true,
-                    ..
-                }
-            ) {
-                opt_metadata_preserved = input_path
-                    .metadata()
-                    .map_err(|err| {
-                        // Fail if metadata cannot be preserved
-                        PngError::new(&format!(
-                            "Unable to read metadata from input file {:?}: {}",
-                            input_path, err
-                        ))
-                    })
-                    .map(Some)?;
-                trace!("preserving metadata: {:?}", opt_metadata_preserved);
-            } else {
-                opt_metadata_preserved = None;
-            }
-            PngData::read_file(input_path)?
-        }
         InFile::StdIn => {
-            opt_metadata_preserved = None;
             let mut data = Vec::new();
             stdin()
                 .read_to_end(&mut data)
-                .map_err(|e| PngError::new(&format!("Error reading stdin: {}", e)))?;
+                .map_err(|e| PngError::ReadFailed("stdin".into(), e))?;
             data
         }
     };
@@ -223,14 +190,14 @@ pub fn optimize(input: &InFile, output: &OutFile, opts: &Options) -> PngResult<(
 
     let in_length = in_data.len();
 
-    if is_fully_optimized(in_data.len(), optimized_output.len(), opts) {
+    if is_fully_optimized(in_length, optimized_output.len(), opts) {
         match (output, input) {
-            // if p is None, it also means same as the input path
+            // If output path is None, it also means same as the input path
-            (OutFile::Path { path, .. }, InFile::Path(ref input_path))
+            (OutFile::Path { path, .. }, InFile::Path(input_path))
-                if path.as_ref().map_or(true, |p| p == input_path) =>
+                if path.as_ref().is_none_or(|p| p == input_path) =>
             {
-                info!("{}: Could not optimize further, no change written", input);
+                info!("Could not optimize further, no change written: {input}");
-                return Ok(());
+                return Ok((in_length, in_length));
             }
             _ => {
                 optimized_output = in_data;
@@ -254,51 +221,65 @@ pub fn optimize(input: &InFile, output: &OutFile, opts: &Options) -> PngResult<(
 
     match (output, input) {
         (OutFile::None, _) => {
-            info!("{}: Running in pretend mode, no output", savings);
+            info!("{savings}: Dry run, no output");
         }
         (&OutFile::StdOut, _) | (&OutFile::Path { path: None, .. }, &InFile::StdIn) => {
             let mut buffer = BufWriter::new(stdout());
             buffer
                 .write_all(&optimized_output)
-                .map_err(|e| PngError::new(&format!("Unable to write to stdout: {}", e)))?;
+                .map_err(|e| PngError::WriteFailed("stdout".into(), e))?;
+            info!("{savings}: stdout");
         }
-        (OutFile::Path { path, .. }, _) => {
+        (
+            OutFile::Path {
+                path,
+                preserve_attrs,
+            },
+            _,
+        ) => {
+            let input_metadata = if *preserve_attrs {
+                input.path().and_then(|in_path| {
+                    let meta = in_path.metadata();
+                    if let Err(e) = &meta {
+                        warn!("Unable to read metadata from {in_path:?}: {e}");
+                    }
+                    meta.ok()
+                })
+            } else {
+                None
+            };
+
             let output_path = path
                 .as_ref()
-                .map(|p| p.as_path())
+                .map_or_else(|| input.path().unwrap(), PathBuf::as_path);
-                .unwrap_or_else(|| input.path().unwrap());
+            let out_file = File::create(output_path)
-            let out_file = File::create(output_path).map_err(|err| {
+                .map_err(|err| PngError::WriteFailed(output_path.display().to_string(), err))?;
-                PngError::new(&format!(
-                    "Unable to write to file {}: {}",
-                    output_path.display(),
-                    err
-                ))
-            })?;
-            if let Some(metadata_input) = &opt_metadata_preserved {
-                copy_permissions(metadata_input, &out_file)?;
-            }
 
-            let mut buffer = BufWriter::new(out_file);
+            let mut buffer = BufWriter::new(&out_file);
             buffer
                 .write_all(&optimized_output)
                 // flush BufWriter so IO errors don't get swallowed silently on close() by drop!
                 .and_then(|()| buffer.flush())
-                .map_err(|e| {
+                .map_err(|e| PngError::WriteFailed(output_path.display().to_string(), e))?;
-                    PngError::new(&format!(
-                        "Unable to write to {}: {}",
-                        output_path.display(),
-                        e
-                    ))
-                })?;
             // force drop and thereby closing of file handle before modifying any timestamp
             std::mem::drop(buffer);
-            if let Some(metadata_input) = &opt_metadata_preserved {
+
-                copy_times(metadata_input, output_path)?;
+            if let Some(metadata_input) = &input_metadata {
+                let set_time = metadata_input
+                    .modified()
+                    .and_then(|m| out_file.set_modified(m));
+                if let Err(e) = set_time {
+                    warn!("Unable to set modification time on {output_path:?}: {e}");
+                }
+                let set_perm = out_file.set_permissions(metadata_input.permissions());
+                if let Err(e) = set_perm {
+                    warn!("Unable to set permissions on {output_path:?}: {e}");
+                }
             }
             info!("{}: {}", savings, output_path.display());
         }
     }
-    Ok(())
+    Ok((in_length, optimized_output.len()))
 }
 
 /// Perform optimization on the input file using the options provided, where the file is already
@@ -323,8 +304,6 @@ pub fn optimize_from_memory(data: &[u8], opts: &Options) -> PngResult<Vec<u8>> {
     }
 }
 
-type TrialResult = (RowFilter, Vec<u8>);
-
 /// Perform optimization on the input PNG object using the options provided
 fn optimize_png(
     png: &mut PngData,
@@ -341,34 +320,24 @@ fn optimize_png(
         raw.ihdr.width, raw.ihdr.height
     );
     report_format("    ", &raw);
-    debug!("    IDAT size = {} bytes", idat_original_size);
+    debug!("    IDAT size = {idat_original_size} bytes");
-    debug!("    File size = {} bytes", file_original_size);
+    debug!("    File size = {file_original_size} bytes");
+
+    let mut opts = opts.to_owned();
+    preprocess_chunks(&mut png.aux_chunks, &mut opts);
 
-    // Check for APNG by presence of acTL chunk
-    let opts = if png.aux_chunks.iter().any(|c| &c.name == b"acTL") {
-        warn!("APNG detected, disabling all reductions");
-        let mut opts = opts.to_owned();
-        opts.interlace = None;
-        opts.bit_depth_reduction = false;
-        opts.color_type_reduction = false;
-        opts.palette_reduction = false;
-        opts.grayscale_reduction = false;
-        Cow::Owned(opts)
-    } else {
-        Cow::Borrowed(opts)
-    };
     let max_size = if opts.force {
         None
     } else {
-        Some(png.estimated_output_size())
+        Some(png.raw.estimated_output_size(&png.idat_data))
     };
-    if let Some(new_png) = optimize_raw(raw.clone(), &opts, deadline.clone(), max_size) {
+    if let Some(result) = optimize_raw(raw.clone(), &opts, deadline.clone(), max_size) {
-        png.raw = new_png.raw;
+        png.raw = result.image;
-        png.idat_data = new_png.idat_data;
+        png.idat_data = result.idat_data.unwrap();
+        recompress_frames(png, &opts, deadline, result.filter)?;
+        postprocess_chunks(&mut png.aux_chunks, &png.raw.ihdr, &raw.ihdr);
     }
 
-    postprocess_chunks(png, &opts, deadline, &raw.ihdr);
-
     let output = png.output();
 
     if idat_original_size >= png.idat_data.len() {
@@ -400,6 +369,12 @@ fn optimize_png(
         );
     }
 
+    if opts.interlace == Some(true) && !png.raw.ihdr.interlaced {
+        warn!(
+            "Interlacing was not enabled as it would result in a larger file. To override this, use `--force`."
+        );
+    }
+
     #[cfg(feature = "sanity-checks")]
     assert!(sanity_checks::validate_output(&output, original_data));
 
@@ -412,186 +387,155 @@ fn optimize_raw(
     opts: &Options,
     deadline: Arc<Deadline>,
     max_size: Option<usize>,
-) -> Option<PngData> {
+) -> Option<Candidate> {
-    // Libdeflate has four algorithms: 1-4 = 'greedy', 5-7 = 'lazy', 8-9 = 'lazy2', 10-12 = 'near-optimal'
+    // Libdeflate has four algorithms: 0 = 'uncompressed', 1-4 = 'greedy', 5-7 = 'lazy', 8-9 = 'lazy2', 10-12 = 'near-optimal'
     // 5 is the minimumm required for a decent evaluation result
     // 7 is not noticeably slower than 5 and improves evaluation of filters in 'fast' mode (o2 and lower)
     // 8 is a little slower but not noticeably when used only for reductions (o3 and higher)
     // 9 is not appreciably better than 8
     // 10 and higher are quite slow - good for filters but only good for reductions if matching the main zc level
-    let eval_compression = match opts.deflate {
+    let compression = match opts.deflater {
-        Deflaters::Libdeflater { compression } => {
+        Deflater::Libdeflater { compression } => {
             if opts.fast_evaluation { 7 } else { 8 }.min(compression)
         }
         _ => 8,
     };
+    let eval_deflater = Deflater::Libdeflater { compression };
     // If only one filter is selected, use this for evaluations
-    let eval_filters = if opts.filter.len() == 1 {
+    let eval_filters = if opts.filters.len() == 1 {
-        opts.filter.clone()
+        opts.filters.clone()
     } else {
         // None and Bigrams work well together, especially for alpha reductions
-        indexset! {RowFilter::None, RowFilter::Bigrams}
+        indexset! {FilterStrategy::NONE, FilterStrategy::Bigrams}
     };
     // This will collect all versions of images and pick one that compresses best
     let eval = Evaluator::new(
         deadline.clone(),
         eval_filters.clone(),
-        eval_compression,
+        eval_deflater,
         false,
+        opts.deflater == eval_deflater,
     );
-    let mut png = perform_reductions(image.clone(), opts, &deadline, &eval);
+    let mut new_image = perform_reductions(image.clone(), opts, &deadline, &eval);
-    let mut eval_result = eval.get_best_candidate();
+    let eval_result = eval.get_best_candidate();
     if let Some(ref result) = eval_result {
-        png = result.image.clone();
+        new_image = result.image.clone();
     }
-    let reduction_occurred = png.ihdr.color_type != image.ihdr.color_type
+    let reduction_occurred = new_image.ihdr.color_type != image.ihdr.color_type
-        || png.ihdr.bit_depth != image.ihdr.bit_depth
+        || new_image.ihdr.bit_depth != image.ihdr.bit_depth
-        || png.ihdr.interlaced != image.ihdr.interlaced;
+        || new_image.ihdr.interlaced != image.ihdr.interlaced;
 
     if reduction_occurred {
-        report_format("Transformed image to ", &png);
+        report_format("Transformed image to ", &new_image);
     }
 
-    if opts.idat_recoding || reduction_occurred {
+    let (result, deflater) = if opts.idat_recoding || reduction_occurred {
-        let mut filters = opts.filter.clone();
+        let result = perform_trials(
-        let fast_eval = opts.fast_evaluation && (filters.len() > 1 || eval_result.is_some());
+            new_image,
-        let best: Option<TrialResult> = if fast_eval {
+            opts,
-            // Perform a fast evaluation of selected filters followed by a single main compression trial
+            deadline,
-
+            max_size,
-            if eval_result.is_some() {
+            eval_result,
-                // Some filters have already been evaluated, we don't need to try them again
+            eval_filters,
-                filters = filters.difference(&eval_filters).cloned().collect();
+            eval_deflater,
-            }
+        );
-
+        (result?, opts.deflater)
-            if !filters.is_empty() {
+    } else {
-                trace!("Evaluating: {} filters", filters.len());
-                let eval = Evaluator::new(deadline, filters, eval_compression, opts.optimize_alpha);
-                if let Some(ref result) = eval_result {
-                    eval.set_best_size(result.idat_data.len());
-                }
-                eval.try_image(png.clone());
-                if let Some(result) = eval.get_best_candidate() {
-                    eval_result = Some(result);
-                }
-            }
-            // We should have a result here - fail if not (e.g. deadline passed)
-            let result = eval_result?;
-
-            match opts.deflate {
-                Deflaters::Libdeflater { compression } if compression <= eval_compression => {
-                    // No further compression required
-                    Some((result.filter, result.idat_data))
-                }
-                _ => {
-                    debug!("Trying: {}", result.filter);
-                    let best_size = AtomicMin::new(max_size);
-                    perform_trial(&result.filtered, opts, result.filter, &best_size)
-                }
-            }
-        } else {
-            // Perform full compression trials of selected filters and determine the best
-
-            if filters.is_empty() {
-                // Pick a filter automatically
-                if png.ihdr.bit_depth as u8 >= 8 {
-                    // Bigrams is the best all-rounder when there's at least one byte per pixel
-                    filters.insert(RowFilter::Bigrams);
-                } else {
-                    // Otherwise delta filters generally don't work well, so just stick with None
-                    filters.insert(RowFilter::None);
-                }
-            }
-
-            debug!("Trying: {} filters", filters.len());
-
-            let best_size = AtomicMin::new(max_size);
-            let results_iter = filters.into_par_iter().with_max_len(1);
-            let best = results_iter.filter_map(|filter| {
-                if deadline.passed() {
-                    return None;
-                }
-                let filtered = &png.filter_image(filter, opts.optimize_alpha);
-                perform_trial(filtered, opts, filter, &best_size)
-            });
-            best.reduce_with(|i, j| {
-                if i.1.len() < j.1.len() || (i.1.len() == j.1.len() && i.0 < j.0) {
-                    i
-                } else {
-                    j
-                }
-            })
-        };
-
-        if let Some((filter, idat_data)) = best {
-            let image = PngData {
-                raw: png,
-                idat_data,
-                aux_chunks: Vec::new(),
-            };
-            if image.estimated_output_size() < max_size.unwrap_or(usize::MAX) {
-                debug!("Found better combination:");
-                debug!(
-                    "    zc = {}  f = {:8}  {} bytes",
-                    opts.deflate,
-                    filter,
-                    image.idat_data.len()
-                );
-                return Some(image);
-            }
-        }
-    } else if let Some(result) = eval_result {
         // If idat_recoding is off and reductions were attempted but ended up choosing the baseline,
         // we should still check if the evaluator compressed the baseline smaller than the original.
-        let image = PngData {
+        (eval_result?, eval_deflater)
-            raw: result.image,
+    };
-            idat_data: result.idat_data,
-            aux_chunks: Vec::new(),
-        };
-        if image.estimated_output_size() < max_size.unwrap_or(usize::MAX) {
-            debug!("Found better combination:");
-            debug!(
-                "    zc = {}  f = {:8}  {} bytes",
-                eval_compression,
-                result.filter,
-                image.idat_data.len()
-            );
-            return Some(image);
-        }
-    }
 
+    if result.idat_data.is_some()
+        && max_size.is_none_or(|max_size| result.estimated_output_size < max_size)
+    {
+        debug!("Found better result:");
+        debug!("    {}, f = {}", deflater, result.filter);
+        return Some(result);
+    }
     None
 }
 
-/// Execute a compression trial
+/// Perform compression trials
-fn perform_trial(
+fn perform_trials(
-    filtered: &[u8],
+    image: Arc<PngImage>,
     opts: &Options,
-    filter: RowFilter,
+    deadline: Arc<Deadline>,
-    best_size: &AtomicMin,
+    max_size: Option<usize>,
-) -> Option<TrialResult> {
+    mut eval_result: Option<Candidate>,
-    match opts.deflate.deflate(filtered, best_size) {
+    eval_filters: IndexSet<FilterStrategy>,
-        Ok(new_idat) => {
+    eval_deflater: Deflater,
-            let bytes = new_idat.len();
+) -> Option<Candidate> {
-            best_size.set_min(bytes);
+    let mut filters = opts.filters.clone();
-            trace!(
+    let fast_eval = opts.fast_evaluation && (filters.len() > 1 || eval_result.is_some());
-                "    zc = {}  f = {:8}  {} bytes",
+    if fast_eval {
-                opts.deflate,
+        // Perform a fast evaluation of selected filters followed by a single main compression trial
-                filter,
+
-                bytes
+        if eval_result.is_some() {
-            );
+            // Some filters have already been evaluated, we don't need to try them again
-            Some((filter, new_idat))
+            filters = filters.difference(&eval_filters).cloned().collect();
         }
-        Err(PngError::DeflatedDataTooLong(bytes)) => {
+
-            trace!(
+        if !filters.is_empty() {
-                "    zc = {}  f = {:8} >{} bytes",
+            trace!("Evaluating {} filters", filters.len());
-                opts.deflate,
+            let eval = Evaluator::new(
-                filter,
+                deadline,
-                bytes,
+                filters,
+                eval_deflater,
+                opts.optimize_alpha,
+                opts.deflater == eval_deflater,
             );
-            None
+            if let Some(result) = &eval_result {
+                eval.set_best_size(result.estimated_output_size);
+            }
+            eval.try_image(image.clone());
+            if let Some(result) = eval.get_best_candidate() {
+                eval_result = Some(result);
+            }
         }
-        Err(_) => None,
+
+        // We should have a result here - fail if not (e.g. deadline passed)
+        let mut result = eval_result?;
+
+        if result.idat_data.is_none() {
+            // Compress with the main deflater
+            debug!("Trying filter {} with {}", result.filter, opts.deflater);
+            let (data, _) = image.filter_image(result.filter_used.clone(), opts.optimize_alpha);
+            match opts.deflater.deflate(&data, max_size) {
+                Ok(idat_data) => {
+                    result.estimated_output_size = result.image.estimated_output_size(&idat_data);
+                    result.idat_data = Some(idat_data);
+                    trace!("{} bytes", result.estimated_output_size);
+                }
+                Err(PngError::DeflatedDataTooLong(bytes)) => {
+                    trace!(">{bytes} bytes");
+                }
+                Err(_) => (),
+            }
+        }
+        return Some(result);
     }
+
+    // Perform full compression trials of selected filters and determine the best
+
+    if filters.is_empty() {
+        // Pick a filter automatically
+        if image.ihdr.bit_depth as u8 >= 8 {
+            // Bigrams is the best all-rounder when there's at least one byte per pixel
+            filters.insert(FilterStrategy::Bigrams);
+        } else {
+            // Otherwise delta filters generally don't work well, so just stick with None
+            filters.insert(FilterStrategy::NONE);
+        }
+    }
+
+    debug!("Trying {} filters with {}", filters.len(), opts.deflater);
+    let eval = Evaluator::new(deadline, filters, opts.deflater, opts.optimize_alpha, true);
+    if let Some(max_size) = max_size {
+        eval.set_best_size(max_size);
+    }
+    eval.try_image(image);
+    eval.get_best_candidate()
 }
 
 #[derive(Debug)]
@@ -609,6 +553,7 @@ pub struct Deadline {
 }
 
 impl Deadline {
+    #[must_use]
     pub fn new(timeout: Option<Duration>) -> Self {
         Self {
             imp: timeout.map(|timeout| DeadlineImp {
@@ -645,141 +590,57 @@ impl Deadline {
 
 /// Display the format of the image data
 fn report_format(prefix: &str, png: &PngImage) {
+    let interlaced = if png.ihdr.interlaced {
+        "interlaced"
+    } else {
+        "non-interlaced"
+    };
     debug!(
         "{}{}-bit {}, {}",
-        prefix, png.ihdr.bit_depth, png.ihdr.color_type, png.ihdr.interlaced
+        prefix, png.ihdr.bit_depth, png.ihdr.color_type, interlaced
     );
 }
 
-/// Perform cleanup of certain chunks from the `PngData` object, after optimization has been completed
+/// Recompress the additional frames of an APNG
-fn postprocess_chunks(
+fn recompress_frames(
     png: &mut PngData,
     opts: &Options,
     deadline: Arc<Deadline>,
-    orig_ihdr: &IhdrData,
+    filter: FilterStrategy,
-) {
+) -> PngResult<()> {
-    if let Some(iccp_idx) = png.aux_chunks.iter().position(|c| &c.name == b"iCCP") {
+    if !opts.idat_recoding || png.frames.is_empty() {
-        // See if we can replace an iCCP chunk with an sRGB chunk
+        return Ok(());
-        let may_replace_iccp = opts.strip != StripChunks::None && opts.strip.keep(b"sRGB");
-        if may_replace_iccp && png.aux_chunks.iter().any(|c| &c.name == b"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");
-            png.aux_chunks.remove(iccp_idx);
-        } else if let Some(icc) = extract_icc(&png.aux_chunks[iccp_idx]) {
-            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");
-                png.aux_chunks[iccp_idx] = Chunk {
-                    name: *b"sRGB",
-                    data: vec![intent],
-                };
-            } else if opts.idat_recoding {
-                // Try recompressing the profile
-                if let Ok(iccp) = construct_iccp(&icc, opts.deflate) {
-                    let cur_len = png.aux_chunks[iccp_idx].data.len();
-                    let new_len = iccp.data.len();
-                    if new_len < cur_len {
-                        debug!(
-                            "Recompressed iCCP chunk: {} ({} bytes decrease)",
-                            new_len,
-                            cur_len - new_len
-                        );
-                        png.aux_chunks[iccp_idx] = iccp;
-                    }
-                }
-            }
-        }
     }
-
+    // Ensure we don't try to recompress frames with a predefined filter
-    // If the depth/color type has changed, some chunks may be invalid and should be dropped
+    debug_assert!(!matches!(filter, FilterStrategy::Predefined { .. }));
-    // While these could potentially be converted, they have no known use case today and are
+    png.frames
-    // generally more trouble than they're worth
+        .par_iter_mut()
-    let ihdr = &png.raw.ihdr;
+        .with_max_len(1)
-    if orig_ihdr.bit_depth != ihdr.bit_depth || orig_ihdr.color_type != ihdr.color_type {
+        .enumerate()
-        png.aux_chunks.retain(|c| {
+        .try_for_each(|(i, frame)| {
-            let invalid = &c.name == b"bKGD" || &c.name == b"sBIT" || &c.name == b"hIST";
+            if deadline.passed() {
-            if invalid {
+                return Ok(());
-                warn!(
+            }
-                    "Removing {} chunk as it no longer matches the image data",
+            let mut ihdr = png.raw.ihdr.clone();
-                    std::str::from_utf8(&c.name).unwrap()
+            ihdr.width = frame.width;
+            ihdr.height = frame.height;
+            let image = PngImage::new(ihdr, &frame.data)?;
+            let (filtered, _) = image.filter_image(filter.clone(), opts.optimize_alpha);
+            let max_size = Some(frame.data.len() - 1);
+            if let Ok(data) = opts.deflater.deflate(&filtered, max_size) {
+                debug!(
+                    "Recompressed fdAT #{:<2}: {} ({} bytes decrease)",
+                    i,
+                    data.len(),
+                    frame.data.len() - data.len()
                 );
+                frame.data = data;
             }
-            !invalid
+            Ok(())
-        });
-    }
-
-    // Find fdAT chunks and attempt to recompress them
-    // Note if there are multiple fdATs per frame then decompression will fail and nothing will change
-    let mut fdat: Vec<_> = png
-        .aux_chunks
-        .iter_mut()
-        .filter(|c| &c.name == b"fdAT")
-        .collect();
-    if opts.idat_recoding && !fdat.is_empty() {
-        let buffer_size = orig_ihdr.raw_data_size();
-        fdat.par_iter_mut()
-            .with_max_len(1)
-            .enumerate()
-            .for_each(|(i, c)| {
-                if deadline.passed() || c.data.len() <= 4 {
-                    return;
-                }
-                if let Ok(mut data) = deflate::inflate(&c.data[4..], buffer_size).and_then(|data| {
-                    let max_size = AtomicMin::new(Some(c.data.len() - 5));
-                    opts.deflate.deflate(&data, &max_size)
-                }) {
-                    debug!(
-                        "Recompressed fdAT #{:<2}: {} ({} bytes decrease)",
-                        i,
-                        c.data.len(),
-                        c.data.len() - 4 - data.len()
-                    );
-                    c.data.truncate(4);
-                    c.data.append(&mut data);
-                }
-            })
-    }
-}
-
-/// Check if an image was already optimized prior to oxipng's operations
-fn is_fully_optimized(original_size: usize, optimized_size: usize, opts: &Options) -> bool {
-    original_size <= optimized_size && !opts.force
-}
-
-fn copy_permissions(metadata_input: &Metadata, out_file: &File) -> PngResult<()> {
-    out_file
-        .set_permissions(metadata_input.permissions())
-        .map_err(|err_io| {
-            PngError::new(&format!(
-                "unable to set permissions for output file: {}",
-                err_io
-            ))
         })
 }
 
-#[cfg(not(feature = "filetime"))]
+/// Check if an image was already optimized prior to oxipng's operations
-fn copy_times(_: &Metadata, _: &Path) -> PngResult<()> {
+const fn is_fully_optimized(original_size: usize, optimized_size: usize, opts: &Options) -> bool {
-    Ok(())
+    original_size <= optimized_size && !opts.force
-}
-
-#[cfg(feature = "filetime")]
-fn copy_times(input_path_meta: &Metadata, out_path: &Path) -> PngResult<()> {
-    let atime = filetime::FileTime::from_last_access_time(input_path_meta);
-    let mtime = filetime::FileTime::from_last_modification_time(input_path_meta);
-    trace!(
-        "attempting to set file times: atime: {:?}, mtime: {:?}",
-        atime,
-        mtime
-    );
-    filetime::set_file_times(out_path, atime, mtime).map_err(|err_io| {
-        PngError::new(&format!(
-            "unable to set file times on {:?}: {}",
-            out_path, err_io
-        ))
-    })
 }

src/main.rs

@@ -1,99 +1,172 @@
-#![warn(trivial_casts, trivial_numeric_casts, unused_import_braces)]
-#![deny(missing_debug_implementations, missing_copy_implementations)]
-#![warn(clippy::expl_impl_clone_on_copy)]
-#![warn(clippy::float_cmp_const)]
-#![warn(clippy::linkedlist)]
-#![warn(clippy::map_flatten)]
-#![warn(clippy::match_same_arms)]
-#![warn(clippy::mem_forget)]
-#![warn(clippy::mut_mut)]
-#![warn(clippy::mutex_integer)]
-#![warn(clippy::needless_continue)]
-#![warn(clippy::path_buf_push_overwrite)]
-#![warn(clippy::range_plus_one)]
-#![allow(clippy::cognitive_complexity)]
-
 #[cfg(not(feature = "parallel"))]
 mod rayon;
 
 #[cfg(feature = "zopfli")]
-use std::num::NonZeroU8;
+use std::num::NonZeroU64;
-use std::{ffi::OsString, fs::DirBuilder, io::Write, path::PathBuf, process::exit, time::Duration};
+use std::{
+    ffi::{OsStr, OsString},
+    fs::DirBuilder,
+    io::{IsTerminal, Write, stdout},
+    path::PathBuf,
+    process::ExitCode,
+    sync::atomic::{AtomicUsize, Ordering::AcqRel},
+    time::Duration,
+};
 
 use clap::ArgMatches;
 mod cli;
 use indexmap::IndexSet;
-use log::{error, warn, Level, LevelFilter};
+use log::{Level, LevelFilter, error, warn};
-use oxipng::{Deflaters, InFile, Options, OutFile, RowFilter, StripChunks};
+#[cfg(feature = "zopfli")]
+use oxipng::ZopfliOptions;
+use oxipng::{
+    Deflater, FilterStrategy, InFile, OptimizationResult, Options, OutFile, PngError, StripChunks,
+};
 use rayon::prelude::*;
 
 use crate::cli::DISPLAY_CHUNKS;
 
-fn main() {
+fn main() -> ExitCode {
     let matches = cli::build_command()
         // Set the value parser for filters which isn't appropriate to do in the build_command function
         .mut_arg("filters", |arg| {
             arg.value_parser(|x: &str| {
-                parse_numeric_range_opts(x, 0, RowFilter::LAST)
+                parse_numeric_range_opts(x, 0, 9).map_err(|_| "Invalid option for filters")
-                    .map_err(|_| "Invalid option for filters")
             })
         })
         .after_help("Run `oxipng --help` to see full details of all options")
         .after_long_help("")
         .get_matches_from(std::env::args());
 
-    if matches.get_flag("backup") {
+    let (mut out_file, out_dir, opts) = match parse_opts_into_struct(&matches) {
-        eprintln!("The --backup flag is no longer supported. Please use --out or --dir to preserve your existing files.");
-        exit(1)
-    }
-
-    let (out_file, out_dir, opts) = match parse_opts_into_struct(&matches) {
         Ok(x) => x,
         Err(x) => {
-            error!("{}", x);
+            error!("{x}");
-            exit(1)
+            return ExitCode::FAILURE;
         }
     };
 
-    let files = collect_files(
+    // Determine input and output
-        #[cfg(windows)]
+    let file_args = matches.get_many::<PathBuf>("files").unwrap().cloned();
-        matches
+    #[cfg(windows)]
-            .get_many::<PathBuf>("files")
+    let inputs: Vec<_> = file_args.flat_map(apply_glob_pattern).collect();
-            .unwrap()
+    #[cfg(not(windows))]
-            .cloned()
+    let inputs: Vec<_> = file_args.collect();
-            .flat_map(apply_glob_pattern)
+    let using_stdin = inputs.len() == 1 && inputs[0].to_str() == Some("-");
-            .collect(),
+    if using_stdin && out_dir.is_some() {
-        #[cfg(not(windows))]
+        error!("Cannot use --dir when reading from stdin.");
-        matches
+        return ExitCode::FAILURE;
-            .get_many::<PathBuf>("files")
+    }
-            .unwrap()
+    if using_stdin && matches!(out_file, OutFile::Path { path: None, .. }) {
-            .cloned()
+        out_file = OutFile::StdOut;
-            .collect(),
+    }
-        &out_dir,
+    let using_stdout = matches!(out_file, OutFile::StdOut);
-        &out_file,
+    let json = matches.get_flag("json");
-        matches.get_flag("recursive"),
+    if using_stdout && json {
-        true,
+        error!("Cannot use --json when writing to stdout.");
-    );
+        return ExitCode::FAILURE;
+    }
 
-    let success = files.into_par_iter().filter(|(input, output)| {
+    let files = if using_stdin {
-        match oxipng::optimize(input, output, &opts) {
+        vec![(InFile::StdIn, out_file)]
-            // For optimizing single files, this will return the correct exit code always.
+    } else {
-            // For recursive optimization, the correct choice is a bit subjective.
+        collect_files(
-            // We're choosing to return a 0 exit code if ANY file in the set
+            inputs,
-            // runs correctly.
+            &out_dir,
-            // The reason for this is that recursion may pick up files that are not
+            &out_file,
-            // PNG files, and return an error for them.
+            matches.get_flag("recursive"),
-            // We don't really want to return an error code for those files.
+            true,
-            Ok(_) => true,
+        )
-            Err(e) => {
+    };
-                error!("{}: {}", input, e);
+
-                false
+    let is_verbose = matches.get_count("verbose") > 0;
-            }
+    let print_summary = !matches.get_flag("quiet") && !using_stdout;
+    let print_progress = print_summary && !is_verbose && stdout().is_terminal();
+    let total_files = files.len();
+    let num_processed = AtomicUsize::new(0);
+    if print_progress {
+        print!("Files processed: 0/{}...", total_files);
+        stdout().flush().ok();
+    }
+    let process = |(input, output): &(InFile, OutFile)| {
+        let result = process_file(input, output, &opts);
+        if print_progress && matches!(result, OptimizationResult::Ok(_)) {
+            let value = num_processed.fetch_add(1, AcqRel) + 1;
+            print!("\rFiles processed: {}/{}...", value, total_files);
+            stdout().flush().ok();
         }
-    });
+        result
+    };
+    let results: Vec<OptimizationResult> = if matches.get_flag("parallel-files") {
+        files.par_iter().map(process).collect()
+    } else {
+        files.iter().map(process).collect()
+    };
 
-    if success.count() == 0 {
+    // Collect stats
-        exit(1);
+    let mut num_succeeded = 0;
+    let mut num_not_optimized = 0;
+    let mut num_failed = 0;
+    let mut total_in: i64 = 0;
+    let mut total_out: i64 = 0;
+    for result in &results {
+        match result {
+            Ok((insize, outsize)) => {
+                num_succeeded += 1;
+                total_in += *insize as i64;
+                total_out += *outsize as i64;
+                if !opts.force && insize == outsize {
+                    num_not_optimized += 1;
+                }
+            }
+            Err(PngError::C2PAMetadataPreventsChanges | PngError::InflatedDataTooLong(_)) => {}
+            Err(_) => num_failed += 1,
+        }
+    }
+
+    // Print results
+    if json {
+        json_output(&files, &results);
+    } else if print_summary {
+        let in_bytes = format_bytes(total_in, true);
+        let out_bytes = format_bytes(total_out, true);
+        let saved = total_in - total_out;
+        let saved_bytes = format_bytes(saved, false);
+        let percent = if total_in > 0 {
+            saved as f64 / total_in as f64 * 100_f64
+        } else {
+            0_f64
+        };
+        if is_verbose {
+            println!("--------------------");
+        }
+        println!("\rFiles processed: {num_succeeded}/{total_files}   ");
+        println!("Input size: {}", in_bytes);
+        println!("Output size: {}", out_bytes);
+        println!("Total saved: {} ({:.2}%)", saved_bytes, percent);
+        if num_not_optimized == 1 {
+            println!("({num_not_optimized} file could not be optimized further)");
+        } else if num_not_optimized > 0 {
+            println!("({num_not_optimized} files could not be optimized further)");
+        }
+        if matches.get_flag("dry-run") {
+            println!("Dry run, no changes saved");
+        }
+    }
+
+    // For optimizing single files, this will return the correct exit code always.
+    // For recursive optimization, the correct choice is a bit subjective.
+    // We're choosing to return a 0 exit code if ANY file in the set
+    // runs correctly.
+    // The reason for this is that recursion may pick up files that are not
+    // PNG files, and return an error for them.
+    // We don't really want to return an error code for those files.
+    if num_succeeded > 0 {
+        ExitCode::SUCCESS
+    } else if num_failed > 0 {
+        ExitCode::FAILURE
+    } else {
+        ExitCode::from(3)
     }
 }
 
@@ -105,10 +178,8 @@ fn collect_files(
     top_level: bool, //explicitly specify files
 ) -> Vec<(InFile, OutFile)> {
     let mut in_out_pairs = Vec::new();
-    let allow_stdin = top_level && files.len() == 1;
     for input in files {
-        let using_stdin = allow_stdin && input.to_str().map_or(false, |p| p == "-");
+        if input.is_dir() {
-        if !using_stdin && input.is_dir() {
             if recursive {
                 match input.read_dir() {
                     Ok(dir) => {
@@ -124,7 +195,16 @@ fn collect_files(
                 warn!("{} is a directory, skipping", input.display());
             }
             continue;
-        };
+        }
+
+        // Skip non png files if not given on top level
+        if !top_level && {
+            let extension = input.extension().map(OsStr::to_ascii_lowercase);
+            extension != Some(OsString::from("png")) && extension != Some(OsString::from("apng"))
+        } {
+            continue;
+        }
+
         let out_file =
             if let (Some(out_dir), &OutFile::Path { preserve_attrs, .. }) = (out_dir, out_file) {
                 let path = Some(out_dir.join(input.file_name().unwrap()));
@@ -135,19 +215,7 @@ fn collect_files(
             } else {
                 (*out_file).clone()
             };
-        let in_file = if using_stdin {
+        let in_file = InFile::Path(input);
-            InFile::StdIn
-        } else {
-            // Skip non png files if not given on top level
-            if !top_level && {
-                let extension = input.extension().map(|f| f.to_ascii_lowercase());
-                extension != Some(OsString::from("png"))
-                    && extension != Some(OsString::from("apng"))
-            } {
-                continue;
-            }
-            InFile::Path(input)
-        };
         in_out_pairs.push((in_file, out_file));
     }
     in_out_pairs
@@ -157,7 +225,8 @@ fn collect_files(
 fn apply_glob_pattern(path: PathBuf) -> Vec<PathBuf> {
     let matches = path
         .to_str()
-        .and_then(|pattern| glob::glob(pattern).ok())
+        // Use MatchOptions::default() to disable case-sensitivity
+        .and_then(|pattern| glob::glob_with(pattern, glob::MatchOptions::default()).ok())
         .map(|paths| paths.flatten().collect::<Vec<_>>());
 
     match matches {
@@ -171,8 +240,9 @@ fn parse_opts_into_struct(
 ) -> Result<(OutFile, Option<PathBuf>, Options), String> {
     let log_level = match matches.get_count("verbose") {
         _ if matches.get_flag("quiet") => LevelFilter::Off,
-        0 => LevelFilter::Info,
+        0 => LevelFilter::Warn,
-        1 => LevelFilter::Debug,
+        1 => LevelFilter::Info,
+        2 => LevelFilter::Debug,
         _ => LevelFilter::Trace,
     };
     env_logger::builder()
@@ -181,7 +251,8 @@ fn parse_opts_into_struct(
             match record.level() {
                 Level::Error | Level::Warn => {
                     let style = buf.default_level_style(record.level());
-                    writeln!(buf, "{style}{}{style:#}", record.args())
+                    // Prepend carriage return to clear progress line
+                    writeln!(buf, "\r{style}{}{style:#}", record.args())
                 }
                 // Leave info, debug and trace unstyled
                 _ => writeln!(buf, "{}", record.args()),
@@ -195,11 +266,39 @@ fn parse_opts_into_struct(
         Some(level) => Options::from_preset(level.parse::<u8>().unwrap()),
     };
 
-    if let Some(x) = matches.get_one::<IndexSet<u8>>("filters") {
+    // Get custom brute settings and rebuild the filter set to apply them
-        opts.filter.clear();
+    let mut brute_lines = matches.get_one::<usize>("brute-lines").copied();
-        for &f in x {
+    let mut brute_level = matches.get_one::<i64>("brute-level").map(|x| *x as u8);
-            opts.filter.insert(f.try_into().unwrap());
+    let mut new_filters = IndexSet::new();
+    for mut f in opts.filters.drain(..) {
+        if let FilterStrategy::Brute { num_lines, level } = &mut f {
+            *num_lines = brute_lines.unwrap_or(*num_lines);
+            *level = brute_level.unwrap_or(*level);
+            // If custom settings were not given, we still need to retain the default values
+            // from the preset so we can re-apply them if the filters are overridden below
+            brute_lines = Some(*num_lines);
+            brute_level = Some(*level);
         }
+        new_filters.insert(f);
+    }
+    opts.filters = new_filters;
+
+    if let Some(x) = matches.get_one::<IndexSet<u8>>("filters") {
+        opts.filters = x
+            .iter()
+            .map(|&f| match f {
+                0..=4 => FilterStrategy::Basic(f.try_into().unwrap()),
+                5 => FilterStrategy::MinSum,
+                6 => FilterStrategy::Entropy,
+                7 => FilterStrategy::Bigrams,
+                8 => FilterStrategy::BigEnt,
+                9 => FilterStrategy::Brute {
+                    num_lines: brute_lines.unwrap_or(3),
+                    level: brute_level.unwrap_or(1),
+                },
+                _ => unreachable!(),
+            })
+            .collect();
     }
 
     if let Some(&num) = matches.get_one::<u64>("timeout") {
@@ -209,9 +308,9 @@ fn parse_opts_into_struct(
     let out_dir = if let Some(path) = matches.get_one::<PathBuf>("output_dir") {
         if !path.exists() {
             match DirBuilder::new().recursive(true).create(path) {
-                Ok(_) => (),
+                Ok(()) => (),
-                Err(x) => return Err(format!("Could not create output directory {}", x)),
+                Err(x) => return Err(format!("Could not create output directory {x}")),
-            };
+            }
         } else if !path.is_dir() {
             return Err(format!(
                 "{} is an existing file (not a directory), cannot create directory",
@@ -223,7 +322,7 @@ fn parse_opts_into_struct(
         None
     };
 
-    let out_file = if matches.get_flag("pretend") {
+    let out_file = if matches.get_flag("dry-run") {
         OutFile::None
     } else if matches.get_flag("stdout") {
         OutFile::StdOut
@@ -247,6 +346,8 @@ fn parse_opts_into_struct(
 
     opts.fix_errors = matches.get_flag("fix");
 
+    opts.max_decompressed_size = matches.get_one::<u64>("max-size").map(|&x| x as usize);
+
     opts.bit_depth_reduction = !matches.get_flag("no-bit-reduction");
 
     opts.color_type_reduction = !matches.get_flag("no-color-reduction");
@@ -266,10 +367,10 @@ fn parse_opts_into_struct(
     opts.idat_recoding = !matches.get_flag("no-recoding");
 
     if let Some(x) = matches.get_one::<String>("interlace") {
-        opts.interlace = if x == "keep" {
+        opts.interlace = match x.as_str() {
-            None
+            "off" | "0" => Some(false),
-        } else {
+            "on" | "1" => Some(true),
-            x.parse::<u8>().unwrap().try_into().ok()
+            _ => None, // keep
         };
     }
 
@@ -286,9 +387,9 @@ fn parse_opts_into_struct(
             })
             .collect::<Result<IndexSet<_>, _>>()?;
         if keep_display {
-            names.extend(DISPLAY_CHUNKS.iter().cloned());
+            names.extend(DISPLAY_CHUNKS.iter().copied());
         }
-        opts.strip = StripChunks::Keep(names)
+        opts.strip = StripChunks::Keep(names);
     }
 
     if let Some(strip) = matches.get_one::<String>("strip") {
@@ -310,7 +411,7 @@ fn parse_opts_into_struct(
                     }
                     let name = parse_chunk_name(x)?;
                     if FORBIDDEN_CHUNKS.contains(&name) {
-                        return Err(format!("{} chunk is not allowed to be stripped", x));
+                        return Err(format!("{x} chunk is not allowed to be stripped"));
                     }
                     Ok(name)
                 })
@@ -323,15 +424,32 @@ fn parse_opts_into_struct(
         opts.strip = StripChunks::Safe;
     }
 
+    #[cfg(feature = "zopfli")]
     if matches.get_flag("zopfli") {
-        #[cfg(feature = "zopfli")]
+        let iteration_count = *matches.get_one::<NonZeroU64>("iterations").unwrap();
-        if let Some(iterations) = NonZeroU8::new(15) {
+        let iterations_without_improvement = *matches
-            opts.deflate = Deflaters::Zopfli { iterations };
+            .get_one::<NonZeroU64>("iterations-without-improvement")
-        }
+            .unwrap_or(&NonZeroU64::MAX);
-    } else if let Deflaters::Libdeflater { compression } = &mut opts.deflate {
+
-        if let Some(x) = matches.get_one::<i64>("compression") {
+        if iterations_without_improvement > iteration_count
-            *compression = *x as u8;
+            && iterations_without_improvement != NonZeroU64::MAX
+        {
+            warn!(
+                "--ziwi ({}) is higher than --zi ({}) and will never be reached.",
+                iterations_without_improvement, iteration_count
+            );
         }
+
+        opts.deflater = Deflater::Zopfli(ZopfliOptions {
+            iteration_count,
+            iterations_without_improvement,
+            ..Default::default()
+        });
+    }
+    if let (Deflater::Libdeflater { compression }, Some(x)) =
+        (&mut opts.deflater, matches.get_one::<i64>("compression"))
+    {
+        *compression = *x as u8;
     }
 
     #[cfg(feature = "parallel")]
@@ -349,7 +467,7 @@ fn parse_chunk_name(name: &str) -> Result<[u8; 4], String> {
     name.trim()
         .as_bytes()
         .try_into()
-        .map_err(|_| format!("Invalid chunk name {}", name))
+        .map_err(|_| format!("Invalid chunk name {name}"))
 }
 
 fn parse_numeric_range_opts(
@@ -404,3 +522,133 @@ fn parse_numeric_range_opts(
 
     Err(ERROR_MESSAGE.to_owned())
 }
+
+fn process_file(input: &InFile, output: &OutFile, opts: &Options) -> OptimizationResult {
+    if let (Some(max_size), InFile::Path(path)) = (opts.max_decompressed_size, input) {
+        if path.metadata().is_ok_and(|m| m.len() > max_size as u64) {
+            warn!("{input}: Skipped: File exceeds the maximum size ({max_size} bytes)");
+            return Err(PngError::InflatedDataTooLong(max_size));
+        }
+    }
+
+    let result = oxipng::optimize(input, output, opts);
+    match &result {
+        Ok(_) => {}
+        Err(e @ PngError::C2PAMetadataPreventsChanges | e @ PngError::InflatedDataTooLong(_)) => {
+            warn!("{input}: Skipped: {e}");
+        }
+        Err(e) => {
+            error!("{input}: {e}");
+        }
+    }
+    result
+}
+
+/// Write optimization results as json.
+/// ```
+/// {
+///   "results": [
+///     {
+///       "input": string,
+///       "status": "success",
+///       "output": string|null,
+///       "insize": number,
+///       "outsize": number
+///     },
+///     {
+///       "input": string,
+///       "status": "error",
+///       "error": string
+///     }
+///   ]
+/// }
+/// ```
+fn json_output(files: &[(InFile, OutFile)], results: &[OptimizationResult]) {
+    print!(r#"{{"results":["#);
+    let mut first = true;
+    results
+        .iter()
+        .zip(files)
+        .for_each(|(result, (input, output))| {
+            if !first {
+                print!(",");
+            }
+            print!(r#"{{"input":"{}","#, json_escape(&input.to_string()));
+            match result {
+                Ok((insize, outsize)) => {
+                    let outpath = match output {
+                        OutFile::None => "null".to_owned(),
+                        OutFile::Path { path: None, .. } => {
+                            format!(r#""{}""#, json_escape(&input.to_string()))
+                        }
+                        OutFile::Path { path: Some(p), .. } => {
+                            format!(r#""{}""#, json_escape(&p.display().to_string()))
+                        }
+                        OutFile::StdOut => unreachable!(),
+                    };
+                    print!(
+                        r#""status":"success","output":{},"insize":{},"outsize":{}}}"#,
+                        outpath, insize, outsize
+                    );
+                }
+                Err(e) => {
+                    print!(
+                        r#""status":"error","error":"{}"}}"#,
+                        json_escape(&e.to_string())
+                    );
+                }
+            }
+            first = false;
+        });
+    print!("]}}");
+}
+
+fn json_escape(string: &str) -> String {
+    string
+        .replace("\\", "\\\\")
+        .replace("\"", "\\\"")
+        .replace("\n", "\\n")
+        .replace("\t", "\\t")
+        .replace("\r", "\\r")
+        .replace("\x08", "\\b")
+        .replace("\x0c", "\\f")
+}
+
+/// Format byte counts as IEC units to 3 significant figures.
+fn format_bytes(count: i64, include_raw: bool) -> String {
+    const K: i64 = 1 << 10;
+    const M: i64 = 1 << 20;
+    const G: i64 = 1 << 30;
+    fn format_3sf(value: f64) -> String {
+        match value.abs() {
+            ..9.995 => format!("{:.2}", value),
+            9.995..99.95 => format!("{:.1}", value),
+            _ => format!("{:.0}", value),
+        }
+    }
+    let formatted = match count.abs() {
+        ..K => format!("{} bytes", count),
+        K..M => format!("{} KiB", format_3sf(count as f64 / K as f64)),
+        M..G => format!("{} MiB", format_3sf(count as f64 / M as f64)),
+        _ => format!("{} GiB", format_3sf(count as f64 / G as f64)),
+    };
+    if include_raw && count.abs() >= K {
+        format!("{} ({} bytes)", formatted, count)
+    } else {
+        formatted
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::format_bytes;
+
+    #[test]
+    fn test_format_bytes() {
+        assert_eq!(format_bytes(1023, false), "1023 bytes");
+        assert_eq!(format_bytes(800_000, false), "781 KiB");
+        assert_eq!(format_bytes(12_500_000, false), "11.9 MiB");
+        assert_eq!(format_bytes(2_000_000_000, false), "1.86 GiB");
+        assert_eq!(format_bytes(-1024, false), "-1.00 KiB");
+    }
+}

src/options.rs

@@ -4,11 +4,13 @@ use std::{
     time::Duration,
 };
 
-use indexmap::{indexset, IndexSet};
+use indexmap::{IndexSet, indexset};
 use log::warn;
 
-use crate::{deflate::Deflaters, filters::RowFilter, headers::StripChunks, interlace::Interlacing};
+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.
@@ -29,16 +31,18 @@ impl OutFile {
     /// Construct a new `OutFile` with the given path.
     ///
     /// This is a convenience method for `OutFile::Path { path: Some(path), preserve_attrs: false }`.
-    pub fn from_path(path: PathBuf) -> Self {
+    #[must_use]
-        OutFile::Path {
+    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 {
-            OutFile::Path {
+            Self::Path {
                 path: Some(ref p), ..
             } => Some(p.as_path()),
             _ => None,
@@ -46,7 +50,8 @@ impl OutFile {
     }
 }
 
-/// Where to read images from
+/// 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),
@@ -54,10 +59,11 @@ pub enum InFile {
 }
 
 impl InFile {
+    #[must_use]
     pub fn path(&self) -> Option<&Path> {
         match *self {
-            InFile::Path(ref p) => Some(p.as_path()),
+            Self::Path(ref p) => Some(p.as_path()),
-            InFile::StdIn => None,
+            Self::StdIn => None,
         }
     }
 }
@@ -65,15 +71,15 @@ impl InFile {
 impl fmt::Display for InFile {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
-            InFile::Path(ref p) => write!(f, "{}", p.display()),
+            Self::Path(ref p) => write!(f, "{}", p.display()),
-            InFile::StdIn => f.write_str("stdin"),
+            Self::StdIn => f.write_str("stdin"),
         }
     }
 }
 
 impl<T: Into<PathBuf>> From<T> for InFile {
     fn from(s: T) -> Self {
-        InFile::Path(s.into())
+        Self::Path(s.into())
     }
 }
 
@@ -88,19 +94,20 @@ pub struct Options {
     ///
     /// Default: `false`
     pub force: bool,
-    /// Which RowFilters to try on the file
+    /// Which `FilterStrategy` to try on the file
     ///
     /// Default: `None,Sub,Entropy,Bigrams`
-    pub filter: IndexSet<RowFilter>,
+    pub filters: IndexSet<FilterStrategy>,
-    /// Whether to change the interlacing type of the file.
+    /// Whether to change the interlacing of the file.
     ///
-    /// `None` will not change the current interlacing type.
+    /// - `None` will not change the current interlacing.
+    /// - `Some(x)` will turn interlacing on or off.
     ///
-    /// `Some(x)` will change the file to interlacing mode `x`.
+    /// Default: `Some(false)`
-    ///
+    pub interlace: Option<bool>,
-    /// Default: `Some(Interlacing::None)`
-    pub interlace: Option<Interlacing>,
     /// Whether to allow transparent pixels to be altered to improve compression.
+    ///
+    /// Default: `false`
     pub optimize_alpha: bool,
     /// Whether to attempt bit depth reduction
     ///
@@ -133,23 +140,31 @@ pub struct Options {
     ///
     /// Default: `None`
     pub strip: StripChunks,
-    /// Which DEFLATE algorithm to use
+    /// Which DEFLATE (zlib) algorithm to use
+    #[cfg_attr(feature = "zopfli", doc = "(e.g. Zopfli)")]
     ///
     /// Default: `Libdeflater`
-    pub deflate: Deflaters,
+    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 {
-    pub fn from_preset(level: u8) -> Options {
+    #[must_use]
-        let opts = Options::default();
+    pub fn from_preset(level: u8) -> Self {
+        let opts = Self::default();
         match level {
             0 => opts.apply_preset_0(),
             1 => opts.apply_preset_1(),
@@ -165,77 +180,112 @@ impl Options {
         }
     }
 
-    pub fn max_compression() -> Options {
+    #[must_use]
-        Options::from_preset(6)
+    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.filter.clear();
+        self.filters.clear();
-        if let Deflaters::Libdeflater { compression } = &mut self.deflate {
+        self.deflater = Deflater::Libdeflater { compression: 5 };
-            *compression = 5;
-        }
         self
     }
 
     fn apply_preset_1(mut self) -> Self {
-        self.filter.clear();
+        self.filters.clear();
-        if let Deflaters::Libdeflater { compression } = &mut self.deflate {
+        self.deflater = Deflater::Libdeflater { compression: 10 };
-            *compression = 10;
-        }
         self
     }
 
-    fn apply_preset_2(self) -> Self {
+    const fn apply_preset_2(self) -> Self {
         self
     }
 
     fn apply_preset_3(mut self) -> Self {
         self.fast_evaluation = false;
-        self.filter = indexset! {
+        self.filters = indexset! {
-            RowFilter::None,
+            FilterStrategy::NONE,
-            RowFilter::Bigrams,
+            FilterStrategy::Bigrams,
-            RowFilter::BigEnt,
+            FilterStrategy::BigEnt,
-            RowFilter::Brute
+            FilterStrategy::Brute {
+                num_lines: 3,
+                level: 1,
+            },
         };
         self
     }
 
     fn apply_preset_4(mut self) -> Self {
-        if let Deflaters::Libdeflater { compression } = &mut self.deflate {
+        self.fast_evaluation = false;
-            *compression = 12;
+        self.filters = indexset! {
-        }
+            FilterStrategy::NONE,
-        self.apply_preset_3()
+            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.filter.insert(RowFilter::Up);
+        self.filters = indexset! {
-        self.filter.insert(RowFilter::MinSum);
+            FilterStrategy::NONE,
-        self.filter.insert(RowFilter::BigEnt);
+            FilterStrategy::SUB,
-        self.filter.insert(RowFilter::Brute);
+            FilterStrategy::UP,
-        if let Deflaters::Libdeflater { compression } = &mut self.deflate {
+            FilterStrategy::MinSum,
-            *compression = 12;
+            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.filter.insert(RowFilter::Average);
+        self.fast_evaluation = false;
-        self.filter.insert(RowFilter::Paeth);
+        self.filters = indexset! {
-        self.apply_preset_5()
+            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() -> Options {
+    fn default() -> Self {
         // Default settings based on -o 2 from the CLI interface
-        Options {
+        Self {
             fix_errors: false,
             force: false,
-            filter: indexset! {RowFilter::None, RowFilter::Sub, RowFilter::Entropy, RowFilter::Bigrams},
+            filters: indexset! {
-            interlace: Some(Interlacing::None),
+                FilterStrategy::NONE,
+                FilterStrategy::SUB,
+                FilterStrategy::Entropy,
+                FilterStrategy::Bigrams
+            },
+            interlace: Some(false),
             optimize_alpha: false,
             bit_depth_reduction: true,
             color_type_reduction: true,
@@ -244,9 +294,10 @@ impl Default for Options {
             idat_recoding: true,
             scale_16: false,
             strip: StripChunks::None,
-            deflate: Deflaters::Libdeflater { compression: 11 },
+            deflater: Deflater::Libdeflater { compression: 11 },
             fast_evaluation: true,
             timeout: None,
+            max_decompressed_size: None,
         }
     }
 }

src/png/mod.rs

@@ -1,35 +1,24 @@
-use std::{
+use std::{fs, path::Path, sync::Arc};
-    fs::File,
-    io::{BufReader, Read, Write},
-    path::Path,
-    sync::Arc,
-};
 
-use bitvec::bitarr;
 use libdeflater::{CompressionLvl, Compressor};
 use log::warn;
-use rgb::ComponentSlice;
 use rustc_hash::FxHashMap;
 
 use crate::{
+    Options, PngResult,
+    apng::*,
     colors::{BitDepth, ColorType},
     deflate,
     error::PngError,
     filters::*,
     headers::*,
-    interlace::{deinterlace_image, interlace_image, Interlacing},
+    interlace::{deinterlace_image, interlace_image},
-    Options,
 };
 
 pub(crate) mod scan_lines;
 
 use self::scan_lines::ScanLines;
 
-/// Compression level to use for the Brute filter strategy
-const BRUTE_LEVEL: i32 = 1; // 1 is fastest, 2-4 are not useful, 5 is slower but more effective
-/// Number of lines to compress with the Brute filter strategy
-const BRUTE_LINES: usize = 4; // Values over 8 are generally not useful
-
 #[derive(Debug, Clone)]
 pub struct PngImage {
     /// The headers stored in the IHDR chunk
@@ -47,44 +36,25 @@ pub struct PngData {
     pub idat_data: Vec<u8>,
     /// All non-critical chunks from the PNG are stored here
     pub aux_chunks: Vec<Chunk>,
+    /// APNG frames
+    pub frames: Vec<Frame>,
 }
 
 impl PngData {
     /// Create a new `PngData` struct by opening a file
     #[inline]
-    pub fn new(filepath: &Path, opts: &Options) -> Result<Self, PngError> {
+    pub fn new(filepath: &Path, opts: &Options) -> PngResult<Self> {
         let byte_data = Self::read_file(filepath)?;
 
         Self::from_slice(&byte_data, opts)
     }
 
-    pub fn read_file(filepath: &Path) -> Result<Vec<u8>, PngError> {
+    pub fn read_file(filepath: &Path) -> PngResult<Vec<u8>> {
-        let file = match File::open(filepath) {
+        fs::read(filepath).map_err(|e| PngError::ReadFailed(filepath.display().to_string(), e))
-            Ok(f) => f,
-            Err(_) => return Err(PngError::new("Failed to open file for reading")),
-        };
-        let file_len = file.metadata().map(|m| m.len() as usize).unwrap_or(0);
-        let mut reader = BufReader::new(file);
-        // Check file for PNG header
-        let mut header = [0; 8];
-        if reader.read_exact(&mut header).is_err() {
-            return Err(PngError::new("Not a PNG file: too small"));
-        }
-        if !file_header_is_valid(&header) {
-            return Err(PngError::new("Invalid PNG header detected"));
-        }
-        // Read raw png data into memory
-        let mut byte_data: Vec<u8> = Vec::with_capacity(file_len);
-        byte_data.extend_from_slice(&header);
-        match reader.read_to_end(&mut byte_data) {
-            Ok(_) => (),
-            Err(_) => return Err(PngError::new("Failed to read from file")),
-        }
-        Ok(byte_data)
     }
 
     /// Create a new `PngData` struct by reading a slice
-    pub fn from_slice(byte_data: &[u8], opts: &Options) -> Result<Self, PngError> {
+    pub fn from_slice(byte_data: &[u8], opts: &Options) -> PngResult<Self> {
         let mut byte_offset: usize = 0;
         // Test that png header is valid
         let header = byte_data.get(0..8).ok_or(PngError::TruncatedData)?;
@@ -97,6 +67,8 @@ impl PngData {
         let mut idat_data: Vec<u8> = Vec::new();
         let mut key_chunks: FxHashMap<[u8; 4], Vec<u8>> = FxHashMap::default();
         let mut aux_chunks: Vec<Chunk> = Vec::new();
+        let mut frames: Vec<Frame> = Vec::new();
+        let mut sequence_number = 0;
         while let Some(chunk) = parse_next_chunk(byte_data, &mut byte_offset, opts.fix_errors)? {
             match &chunk.name {
                 b"IDAT" => {
@@ -105,25 +77,53 @@ impl PngData {
                         aux_chunks.push(Chunk {
                             name: chunk.name,
                             data: Vec::new(),
-                        })
+                        });
                     }
                     idat_data.extend_from_slice(chunk.data);
                 }
                 b"IHDR" | b"PLTE" | b"tRNS" => {
                     key_chunks.insert(chunk.name, chunk.data.to_owned());
                 }
-                _ => {
+                _ if opts.strip.keep(&chunk.name) => {
-                    if opts.strip.keep(&chunk.name) {
+                    if chunk.is_c2pa() {
-                        aux_chunks.push(Chunk {
+                        // StripChunks::None is the default value, so to keep optimizing by default,
-                            name: chunk.name,
+                        // interpret it as stripping the C2PA metadata.
-                            data: chunk.data.to_owned(),
+                        // The C2PA metadata is invalidated if the file changes, so it shouldn't be kept.
-                        })
+                        if opts.strip == StripChunks::None {
-                    } else if chunk.name == *b"acTL" {
+                            continue;
-                        warn!(
+                        }
-                            "Stripping animation data from APNG - image will become standard PNG"
+                        return Err(PngError::C2PAMetadataPreventsChanges);
-                        );
                     }
+                    if chunk.name == *b"fcTL" || chunk.name == *b"fdAT" {
+                        // Validate the sequence number
+                        if read_be_u32(&chunk.data[0..4]) != sequence_number {
+                            return Err(PngError::APNGOutOfOrder);
+                        }
+                        sequence_number += 1;
+                        if chunk.name == *b"fcTL" && !idat_data.is_empty() {
+                            // Only create a Frame if it's after the IDAT (else store it as an aux chunk)
+                            frames.push(Frame::from_fctl_data(chunk.data)?);
+                            continue;
+                        } else if chunk.name == *b"fdAT" {
+                            // Append the data to the last frame
+                            frames
+                                .last_mut()
+                                .ok_or(PngError::APNGOutOfOrder)?
+                                .data
+                                .extend_from_slice(&chunk.data[4..]);
+                            continue;
+                        }
+                    }
+                    // Regular ancillary chunk
+                    aux_chunks.push(Chunk {
+                        name: chunk.name,
+                        data: chunk.data.to_owned(),
+                    });
                 }
+                b"acTL" => {
+                    warn!("Stripping animation data from APNG - image will become standard PNG");
+                }
+                _ => (),
             }
         }
 
@@ -131,64 +131,57 @@ impl PngData {
         if idat_data.is_empty() {
             return Err(PngError::ChunkMissing("IDAT"));
         }
-        let ihdr_chunk = match key_chunks.remove(b"IHDR") {
+        let Some(ihdr_chunk) = key_chunks.remove(b"IHDR") else {
-            Some(ihdr) => ihdr,
+            return Err(PngError::ChunkMissing("IHDR"));
-            None => return Err(PngError::ChunkMissing("IHDR")),
         };
         let ihdr = parse_ihdr_chunk(
             &ihdr_chunk,
             key_chunks.remove(b"PLTE"),
             key_chunks.remove(b"tRNS"),
         )?;
-        let raw_data = deflate::inflate(idat_data.as_ref(), ihdr.raw_data_size())?;
+        if let Some(max) = opts.max_decompressed_size {
-
+            if ihdr.raw_data_size() > max {
-        // Reject files with incorrect width/height or truncated data
+                return Err(PngError::InflatedDataTooLong(max));
-        if raw_data.len() != ihdr.raw_data_size() {
+            }
-            return Err(PngError::TruncatedData);
         }
 
-        let mut raw = PngImage {
+        let raw = PngImage::new(ihdr, &idat_data)?;
-            ihdr,
+
-            data: raw_data,
-        };
-        raw.data = raw.unfilter_image()?;
         // Return the PngData
         Ok(Self {
             idat_data,
             raw: Arc::new(raw),
             aux_chunks,
+            frames,
         })
     }
 
-    /// Return an estimate of the output size which can help with evaluation of very small data
-    pub fn estimated_output_size(&self) -> usize {
-        self.idat_data.len() + self.raw.key_chunks_size()
-    }
-
     /// Format the `PngData` struct into a valid PNG bytestream
+    #[must_use]
     pub fn output(&self) -> Vec<u8> {
         // PNG header
         let mut output = vec![0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A];
         // IHDR
         let mut ihdr_data = Vec::with_capacity(13);
-        ihdr_data.write_all(&self.raw.ihdr.width.to_be_bytes()).ok();
+        ihdr_data.extend_from_slice(&self.raw.ihdr.width.to_be_bytes());
-        ihdr_data
+        ihdr_data.extend_from_slice(&self.raw.ihdr.height.to_be_bytes());
-            .write_all(&self.raw.ihdr.height.to_be_bytes())
+        ihdr_data.extend_from_slice(&[self.raw.ihdr.bit_depth as u8]);
-            .ok();
+        ihdr_data.extend_from_slice(&[
-        ihdr_data.write_all(&[self.raw.ihdr.bit_depth as u8]).ok();
+            self.raw.ihdr.color_type.png_header_code(),
-        ihdr_data
+            0, // Compression -- deflate
-            .write_all(&[self.raw.ihdr.color_type.png_header_code()])
+            0, // Filter method -- 5-way adaptive filtering
-            .ok();
+            self.raw.ihdr.interlaced as u8,
-        ihdr_data.write_all(&[0]).ok(); // Compression -- deflate
+        ]);
-        ihdr_data.write_all(&[0]).ok(); // Filter method -- 5-way adaptive filtering
-        ihdr_data.write_all(&[self.raw.ihdr.interlaced as u8]).ok();
         write_png_block(b"IHDR", &ihdr_data, &mut output);
         // Ancillary chunks - split into those that come before IDAT and those that come after
         let mut aux_split = self.aux_chunks.split(|c| &c.name == b"IDAT");
         let aux_pre = aux_split.next().unwrap();
+        // Many chunks need to be before PLTE, so write all except those that explicitly need to be after
+        // Note: the PNG spec does not say that fcTL needs to be after PLTE, but some decoders expect
+        //       that (see issue #625)
         for chunk in aux_pre
             .iter()
-            .filter(|c| !(&c.name == b"bKGD" || &c.name == b"hIST" || &c.name == b"tRNS"))
+            .filter(|c| !matches!(&c.name, b"bKGD" | b"hIST" | b"tRNS" | b"fcTL"))
         {
             write_png_block(&chunk.name, &chunk.data, &mut output);
         }
@@ -197,7 +190,7 @@ impl PngData {
             ColorType::Indexed { palette } => {
                 let mut palette_data = Vec::with_capacity(palette.len() * 3);
                 for px in palette {
-                    palette_data.extend_from_slice(px.rgb().as_slice());
+                    palette_data.extend_from_slice(px.rgb().as_ref());
                 }
                 write_png_block(b"PLTE", &palette_data, &mut output);
                 if let Some(last_trns) = palette.iter().rposition(|px| px.a != 255) {
@@ -215,20 +208,30 @@ impl PngData {
                 transparent_color: Some(trns),
             } => {
                 // Transparency pixel - 6 byte RGB16
-                let trns_data: Vec<_> = trns.iter().flat_map(|c| c.to_be_bytes()).collect();
+                let trns_data: Vec<_> = trns.iter().flat_map(u16::to_be_bytes).collect();
                 write_png_block(b"tRNS", &trns_data, &mut output);
             }
             _ => {}
         }
         // Special ancillary chunks that need to come after PLTE but before IDAT
+        let mut sequence_number = 0;
         for chunk in aux_pre
             .iter()
-            .filter(|c| &c.name == b"bKGD" || &c.name == b"hIST" || &c.name == b"tRNS")
+            .filter(|c| matches!(&c.name, b"bKGD" | b"hIST" | b"tRNS" | b"fcTL"))
         {
             write_png_block(&chunk.name, &chunk.data, &mut output);
+            if &chunk.name == b"fcTL" {
+                sequence_number += 1;
+            }
         }
         // IDAT data
         write_png_block(b"IDAT", &self.idat_data, &mut output);
+        // APNG frames
+        for frame in self.frames.iter() {
+            write_png_block(b"fcTL", &frame.fctl_data(sequence_number), &mut output);
+            write_png_block(b"fdAT", &frame.fdat_data(sequence_number + 1), &mut output);
+            sequence_number += 2;
+        }
         // Ancillary chunks that come after IDAT
         for aux_post in aux_split {
             for chunk in aux_post {
@@ -243,18 +246,33 @@ impl PngData {
 }
 
 impl PngImage {
-    /// Convert the image to the specified interlacing type
+    pub fn new(ihdr: IhdrData, compressed_data: &[u8]) -> PngResult<Self> {
-    /// Returns true if the interlacing was changed, false otherwise
+        let raw_data = deflate::inflate(compressed_data, ihdr.raw_data_size())?;
-    /// The `interlace` parameter specifies the *new* interlacing mode
+
+        // Reject files with incorrect width/height or truncated data
+        if raw_data.len() != ihdr.raw_data_size() {
+            return Err(PngError::TruncatedData);
+        }
+
+        let mut image = Self {
+            ihdr,
+            data: raw_data,
+        };
+        image.data = image.unfilter_image()?;
+        Ok(image)
+    }
+
+    /// Enable or disable interlacing
+    /// Returns the new image if the interlacing was changed, None otherwise
     /// Assumes that the data has already been de-filtered
     #[inline]
     #[must_use]
-    pub fn change_interlacing(&self, interlace: Interlacing) -> Option<PngImage> {
+    pub fn change_interlacing(&self, interlace: bool) -> Option<Self> {
         if interlace == self.ihdr.interlaced {
             return None;
         }
 
-        Some(if interlace == Interlacing::Adam7 {
+        Some(if interlace {
             // Convert progressive to interlaced data
             interlace_image(self)
         } else {
@@ -265,13 +283,15 @@ impl PngImage {
 
     /// Return the number of channels in the image, based on color type
     #[inline]
-    pub fn channels_per_pixel(&self) -> usize {
+    #[must_use]
+    pub const fn channels_per_pixel(&self) -> usize {
         self.ihdr.color_type.channels_per_pixel() as usize
     }
 
     /// Return the number of bytes per channel in the image
     #[inline]
-    pub fn bytes_per_channel(&self) -> usize {
+    #[must_use]
+    pub const fn bytes_per_channel(&self) -> usize {
         match self.ihdr.bit_depth {
             BitDepth::Sixteen => 2,
             // Depths lower than 8 will round up to 1 byte
@@ -280,15 +300,15 @@ impl PngImage {
     }
 
     /// Calculate the size of the PLTE and tRNS chunks
+    #[must_use]
     pub fn key_chunks_size(&self) -> usize {
         match &self.ihdr.color_type {
             ColorType::Indexed { palette } => {
                 let plte = 12 + palette.len() * 3;
-                if let Some(trns) = palette.iter().rposition(|p| p.a != 255) {
+                palette
-                    plte + 12 + trns + 1
+                    .iter()
-                } else {
+                    .rposition(|p| p.a != 255)
-                    plte
+                    .map_or(plte, |trns| plte + 12 + trns + 1)
-                }
             }
             ColorType::Grayscale { transparent_shade } if transparent_shade.is_some() => 12 + 2,
             ColorType::RGB { transparent_color } if transparent_color.is_some() => 12 + 6,
@@ -296,14 +316,21 @@ impl PngImage {
         }
     }
 
+    /// Return an estimate of the output size which can help with evaluation of very small data
+    #[must_use]
+    pub fn estimated_output_size(&self, idat_data: &[u8]) -> usize {
+        idat_data.len() + self.key_chunks_size()
+    }
+
     /// Return an iterator over the scanlines of the image
     #[inline]
+    #[must_use]
     pub fn scan_lines(&self, has_filter: bool) -> ScanLines<'_> {
         ScanLines::new(self, has_filter)
     }
 
     /// Reverse all filters applied on the image, returning an unfiltered IDAT bytestream
-    fn unfilter_image(&self) -> Result<Vec<u8>, PngError> {
+    fn unfilter_image(&self) -> PngResult<Vec<u8>> {
         let mut unfiltered = Vec::with_capacity(self.data.len());
         let bpp = self.bytes_per_channel() * self.channels_per_pixel();
         let mut last_line: Vec<u8> = Vec::new();
@@ -315,8 +342,8 @@ impl PngImage {
                 last_pass = line.pass;
             }
             last_line.resize(line.data.len(), 0);
-            let filter = RowFilter::try_from(line.filter).map_err(|_| PngError::InvalidData)?;
+            let filter = RowFilter::try_from(line.filter).map_err(|()| PngError::InvalidData)?;
-            filter.unfilter_line(bpp, line.data, &last_line, &mut unfiltered_buf)?;
+            filter.unfilter_line(bpp, line.data, &last_line, &mut unfiltered_buf);
             unfiltered.extend_from_slice(&unfiltered_buf);
             std::mem::swap(&mut last_line, &mut unfiltered_buf);
             unfiltered_buf.clear();
@@ -325,7 +352,12 @@ impl PngImage {
     }
 
     /// Apply the specified filter type to all rows in the image
-    pub fn filter_image(&self, filter: RowFilter, optimize_alpha: bool) -> Vec<u8> {
+    #[must_use]
+    pub fn filter_image(
+        &self,
+        strategy: FilterStrategy,
+        optimize_alpha: bool,
+    ) -> (Vec<u8>, FilterStrategy) {
         let mut filtered = Vec::with_capacity(self.data.len());
         let bpp = self.bytes_per_channel() * self.channels_per_pixel();
         // If alpha optimization is enabled, determine how many bytes of alpha there are per pixel
@@ -338,35 +370,58 @@ impl PngImage {
         let mut prev_line = Vec::new();
         let mut prev_pass: Option<u8> = None;
         let mut f_buf = Vec::new();
-        for line in self.scan_lines(false) {
+        // For heuristic strategies, keep track of the actual filter used for each line
+        let mut filters_used = Vec::new();
+        // Pre-allocate buffers for the Bigrams strategy to avoid per-line allocations
+        let (mut bigram_seen, mut bigram_touched) = if matches!(strategy, FilterStrategy::Bigrams) {
+            (vec![false; 0x10000], Vec::<u16>::new())
+        } else {
+            (Vec::new(), Vec::new())
+        };
+        for (i, line) in self.scan_lines(false).enumerate() {
             if prev_pass != line.pass || line.data.len() != prev_line.len() {
                 prev_line = vec![0; line.data.len()];
             }
             // Alpha optimisation may alter the line data, so we need a mutable copy of it
             let mut line_data = line.data.to_vec();
 
-            if filter <= RowFilter::Paeth {
+            if let FilterStrategy::Basic(mut filter) = strategy {
                 // Standard filters
-                let filter = if prev_pass == line.pass || filter <= RowFilter::Sub {
+                if prev_pass != line.pass && filter > RowFilter::Sub {
-                    filter
+                    filter = RowFilter::None;
-                } else {
+                }
-                    RowFilter::None
+                filter.filter_line(bpp, &mut line_data, &prev_line, &mut f_buf, alpha_bytes);
-                };
+                filtered.extend_from_slice(&f_buf);
+                prev_line = line_data;
+            } else if let FilterStrategy::Predefined(lines) = &strategy {
+                // Predefined filter for each line
+                let filter = lines.get(i).unwrap_or(&RowFilter::None);
                 filter.filter_line(bpp, &mut line_data, &prev_line, &mut f_buf, alpha_bytes);
                 filtered.extend_from_slice(&f_buf);
                 prev_line = line_data;
             } else {
                 // Heuristic filter selection strategies
+
+                let mut best_filter = RowFilter::None;
+                if line_data.iter().all(|&x| x == 0) {
+                    // Assume None if the line is all zeros
+                    filtered.push(best_filter as u8);
+                    filtered.extend_from_slice(&line_data);
+                    prev_line = line_data;
+                    filters_used.push(best_filter);
+                    continue;
+                }
+
                 let mut best_line = Vec::new();
                 let mut best_line_raw = Vec::new();
                 // Avoid vertical filtering on first line of each interlacing pass
                 let try_filters = if prev_pass == line.pass {
-                    RowFilter::STANDARD.iter()
+                    RowFilter::ALL.iter()
                 } else {
                     RowFilter::SINGLE_LINE.iter()
                 };
-                match filter {
+                match strategy {
-                    RowFilter::MinSum => {
+                    FilterStrategy::MinSum => {
                         // MSAD algorithm mentioned in libpng reference docs
                         // http://www.libpng.org/pub/png/book/chapter09.html
                         let mut best_size = usize::MAX;
@@ -380,17 +435,18 @@ impl PngImage {
                                 best_size = size;
                                 std::mem::swap(&mut best_line, &mut f_buf);
                                 best_line_raw.clone_from(&line_data);
+                                best_filter = *f;
                             }
                         }
                     }
-                    RowFilter::Entropy => {
+                    FilterStrategy::Entropy => {
                         // Shannon entropy algorithm, from LodePNG
                         // https://github.com/lvandeve/lodepng
                         let mut best_size = i32::MIN;
                         for f in try_filters {
                             f.filter_line(bpp, &mut line_data, &prev_line, &mut f_buf, alpha_bytes);
                             let mut counts = vec![0; 0x100];
-                            for &i in f_buf.iter() {
+                            for &i in &f_buf {
                                 counts[i as usize] += 1;
                             }
                             let size = counts.into_iter().fold(0, |acc, x| {
@@ -403,29 +459,42 @@ impl PngImage {
                                 best_size = size;
                                 std::mem::swap(&mut best_line, &mut f_buf);
                                 best_line_raw.clone_from(&line_data);
+                                best_filter = *f;
                             }
                         }
                     }
-                    RowFilter::Bigrams => {
+                    FilterStrategy::Bigrams => {
                         // Count distinct bigrams, from pngwolf
                         // https://bjoern.hoehrmann.de/pngwolf/
                         let mut best_size = usize::MAX;
                         for f in try_filters {
                             f.filter_line(bpp, &mut line_data, &prev_line, &mut f_buf, alpha_bytes);
-                            let mut set = bitarr![0; 0x10000];
+                            let mut count = 0;
                             for pair in f_buf.windows(2) {
-                                let bigram = (pair[0] as usize) << 8 | pair[1] as usize;
+                                let bigram = ((pair[0] as usize) << 8) | pair[1] as usize;
-                                set.set(bigram, true);
+                                if !bigram_seen[bigram] {
+                                    count += 1;
+                                    if count >= best_size {
+                                        break;
+                                    }
+                                    bigram_seen[bigram] = true;
+                                    bigram_touched.push(bigram as u16);
+                                }
                             }
-                            let size = set.count_ones();
+                            if count < best_size {
-                            if size < best_size {
+                                best_size = count;
-                                best_size = size;
                                 std::mem::swap(&mut best_line, &mut f_buf);
                                 best_line_raw.clone_from(&line_data);
+                                best_filter = *f;
                             }
+                            // Clear only the entries that were touched
+                            for &idx in &bigram_touched {
+                                bigram_seen[idx as usize] = false;
+                            }
+                            bigram_touched.clear();
                         }
                     }
-                    RowFilter::BigEnt => {
+                    FilterStrategy::BigEnt => {
                         // Bigram entropy, combined from Entropy and Bigrams filters
                         let mut best_size = i32::MIN;
                         // FxHasher is the fastest rust hasher currently available for this purpose
@@ -434,7 +503,7 @@ impl PngImage {
                             f.filter_line(bpp, &mut line_data, &prev_line, &mut f_buf, alpha_bytes);
                             counts.clear();
                             for pair in f_buf.windows(2) {
-                                let bigram = (pair[0] as u16) << 8 | pair[1] as u16;
+                                let bigram = (u16::from(pair[0]) << 8) | u16::from(pair[1]);
                                 counts.entry(bigram).and_modify(|e| *e += 1).or_insert(1);
                             }
                             let size = counts.values().fold(0, |acc, &x| acc + ilog2i(x)) as i32;
@@ -442,31 +511,33 @@ impl PngImage {
                                 best_size = size;
                                 std::mem::swap(&mut best_line, &mut f_buf);
                                 best_line_raw.clone_from(&line_data);
+                                best_filter = *f;
                             }
                         }
                     }
-                    RowFilter::Brute => {
+                    FilterStrategy::Brute { num_lines, level } => {
                         // Brute force by compressing each filter attempt
                         // Similar to that of LodePNG but includes some previous lines for context
                         let mut best_size = usize::MAX;
                         let line_start = filtered.len();
                         filtered.resize(filtered.len() + line.data.len() + 1, 0);
                         let mut compressor =
-                            Compressor::new(CompressionLvl::new(BRUTE_LEVEL).unwrap());
+                            Compressor::new(CompressionLvl::new(level.into()).unwrap());
-                        let limit = filtered.len().min((line.data.len() + 1) * BRUTE_LINES);
+                        let limit = filtered.len().min((line.data.len() + 1) * num_lines);
-                        let capacity = compressor.zlib_compress_bound(limit);
+                        let capacity = compressor.deflate_compress_bound(limit);
                         let mut dest = vec![0; capacity];
 
                         for f in try_filters {
                             f.filter_line(bpp, &mut line_data, &prev_line, &mut f_buf, alpha_bytes);
                             filtered[line_start..].copy_from_slice(&f_buf);
                             let size = compressor
-                                .zlib_compress(&filtered[filtered.len() - limit..], &mut dest)
+                                .deflate_compress(&filtered[filtered.len() - limit..], &mut dest)
                                 .unwrap_or(usize::MAX);
                             if size < best_size {
                                 best_size = size;
                                 std::mem::swap(&mut best_line, &mut f_buf);
                                 best_line_raw.clone_from(&line_data);
+                                best_filter = *f;
                             }
                         }
                         filtered.resize(line_start, 0);
@@ -475,11 +546,17 @@ impl PngImage {
                 }
                 filtered.extend_from_slice(&best_line);
                 prev_line = best_line_raw;
+                filters_used.push(best_filter);
             }
 
             prev_pass = line.pass;
         }
-        filtered
+
+        if filters_used.is_empty() {
+            (filtered, strategy)
+        } else {
+            (filtered, FilterStrategy::Predefined(filters_used))
+        }
     }
 }
 
@@ -495,7 +572,7 @@ fn write_png_block(key: &[u8], chunk: &[u8], output: &mut Vec<u8>) {
 }
 
 // Integer approximation for i * log2(i) - much faster than float calculations
-fn ilog2i(i: u32) -> u32 {
+const fn ilog2i(i: u32) -> u32 {
     let log = 32 - i.leading_zeros() - 1;
     i * log + ((i - (1 << log)) << 1)
 }

src/png/scan_lines.rs

@@ -1,4 +1,4 @@
-use crate::{interlace::Interlacing, png::PngImage};
+use crate::png::PngImage;
 
 /// An iterator over the scan lines of a PNG image
 #[derive(Debug, Clone)]
@@ -11,6 +11,7 @@ pub struct ScanLines<'a> {
 }
 
 impl<'a> ScanLines<'a> {
+    #[must_use]
     pub fn new(png: &'a PngImage, has_filter: bool) -> Self {
         Self {
             iter: ScanLineRanges::new(png, has_filter),
@@ -22,6 +23,7 @@ impl<'a> ScanLines<'a> {
 
 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()?;
@@ -67,7 +69,7 @@ impl ScanLineRanges {
             width: png.ihdr.width,
             height: png.ihdr.height,
             left: png.data.len(),
-            pass: if png.ihdr.interlaced == Interlacing::Adam7 {
+            pass: if png.ihdr.interlaced {
                 Some((1, 0))
             } else {
                 None
@@ -79,6 +81,7 @@ impl ScanLineRanges {
 
 impl Iterator for ScanLineRanges {
     type Item = (usize, Option<u8>, usize);
+
     fn next(&mut self) -> Option<Self::Item> {
         if self.left == 0 {
             return None;
@@ -135,7 +138,7 @@ impl Iterator for ScanLineRanges {
                     pixels_per_line += 1;
                 }
                 _ => (),
-            };
+            }
             let current_pass = Some(pass.0);
             if pass.1 + y_steps >= self.height {
                 pass.0 += 1;
@@ -154,7 +157,7 @@ impl Iterator for ScanLineRanges {
             (self.width, None)
         };
         let bits_per_line = pixels_per_line as usize * self.bits_per_pixel;
-        let mut len = (bits_per_line + 7) / 8;
+        let mut len = bits_per_line.div_ceil(8);
         if self.has_filter {
             len += 1;
         }

src/rayon.rs

@@ -1,3 +1,5 @@
+#![allow(dead_code)]
+
 pub mod prelude {
     pub use super::*;
 }
@@ -70,12 +72,10 @@ where
 
 impl<I: Iterator> ParallelIterator for I {}
 
-#[allow(dead_code)]
 pub fn join<A, B>(a: impl FnOnce() -> A, b: impl FnOnce() -> B) -> (A, B) {
     (a(), b())
 }
 
-#[allow(dead_code)]
 pub fn spawn<A>(a: impl FnOnce() -> A) -> A {
     a()
 }

src/reduction/alpha.rs

@@ -7,6 +7,7 @@ use crate::{
 };
 
 /// 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;
@@ -16,7 +17,7 @@ pub fn cleaned_alpha_channel(png: &PngImage) -> Option<PngImage> {
     let colored_bytes = bpp - byte_depth;
 
     let mut reduced = Vec::with_capacity(png.data.len());
-    for pixel in png.data.chunks(bpp) {
+    for pixel in png.data.chunks_exact(bpp) {
         if pixel.iter().skip(colored_bytes).all(|b| *b == 0) {
             reduced.resize(reduced.len() + bpp, 0);
         } else {
@@ -45,7 +46,7 @@ pub fn reduced_alpha_channel(png: &PngImage, optimize_alpha: bool) -> Option<Png
     let mut has_transparency = false;
     let mut used_colors = vec![false; 256];
 
-    for pixel in png.data.chunks(bpp) {
+    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;
@@ -74,19 +75,19 @@ pub fn reduced_alpha_channel(png: &PngImage, optimize_alpha: bool) -> Option<Png
     };
 
     let mut raw_data = Vec::with_capacity(png.data.len());
-    for pixel in png.data.chunks(bpp) {
+    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 transparent = transparency_pixel.map(|trns| match png.ihdr.bit_depth {
-        BitDepth::Sixteen => (trns as u16) << 8 | trns as u16,
+        BitDepth::Sixteen => (u16::from(trns) << 8) | u16::from(trns),
-        _ => trns as u16,
+        _ => u16::from(trns),
     });
     let target_color_type = match png.ihdr.color_type {
         ColorType::GrayscaleAlpha => ColorType::Grayscale {

src/reduction/bit_depth.rs

@@ -16,13 +16,13 @@ pub fn reduced_bit_depth_16_to_8(png: &PngImage, force_scale: bool) -> Option<Pn
     }
 
     // Reduce from 16 to 8 bits per channel per pixel
-    if png.data.chunks(2).any(|pair| pair[0] != pair[1]) {
+    if png.data.chunks_exact(2).any(|pair| pair[0] != pair[1]) {
         // Can't reduce
         return None;
     }
 
     Some(PngImage {
-        data: png.data.iter().step_by(2).cloned().collect(),
+        data: png.data.chunks_exact(2).map(|pair| pair[0]).collect(),
         ihdr: IhdrData {
             color_type: png.ihdr.color_type.clone(),
             bit_depth: BitDepth::Eight,
@@ -41,15 +41,15 @@ pub fn scaled_bit_depth_16_to_8(png: &PngImage) -> Option<PngImage> {
     // Reduce from 16 to 8 bits per channel per pixel by scaling when necessary
     let data = png
         .data
-        .chunks(2)
+        .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 = u16::from_be_bytes([pair[0], pair[1]]) as f64;
+            let val = f32::from(u16::from_be_bytes([pair[0], pair[1]]));
-            (val * 255.0 / 65535.0).round() as u8
+            (val * (255.0 / 65535.0)).round() as u8
         })
         .collect();
 
@@ -70,17 +70,17 @@ pub fn reduced_bit_depth_8_or_less(png: &PngImage) -> Option<PngImage> {
         return None;
     }
 
-    let mut minimum_bits = 1;
+    let minimum_bits = if let ColorType::Indexed { palette } = &png.ihdr.color_type {
-
-    if let ColorType::Indexed { palette } = &png.ihdr.color_type {
         // We can easily determine minimum depth by the palette size
-        minimum_bits = match palette.len() {
+        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;
@@ -110,7 +110,9 @@ pub fn reduced_bit_depth_8_or_less(png: &PngImage) -> Option<PngImage> {
                 break;
             }
         }
-    }
+
+        minimum_bits
+    };
 
     let mut reduced = Vec::with_capacity(png.data.len());
     let mask = (1 << minimum_bits) - 1;
@@ -138,7 +140,7 @@ pub fn reduced_bit_depth_8_or_less(png: &PngImage) -> Option<PngImage> {
         let mut check = reduced_trans;
         let mut bits = minimum_bits;
         while bits < 8 {
-            check = check << bits | check;
+            check = (check << bits) | check;
             bits <<= 1;
         }
         // If the transparency doesn't fit the new bit depth it is therefore unused - set it to None
@@ -188,7 +190,7 @@ pub fn expanded_bit_depth_to_8(png: &PngImage) -> Option<PngImage> {
                     // Expand gray by repeating the bits
                     let mut bits = bit_depth;
                     while bits < 8 {
-                        val = val << bits | val;
+                        val = (val << bits) | val;
                         bits <<= 1;
                     }
                 }
@@ -207,7 +209,7 @@ pub fn expanded_bit_depth_to_8(png: &PngImage) -> Option<PngImage> {
     {
         let mut bits = bit_depth;
         while bits < 8 {
-            trans = trans << bits | trans;
+            trans = (trans << bits) | trans;
             bits <<= 1;
         }
         ColorType::Grayscale {

src/reduction/color.rs

@@ -1,7 +1,7 @@
 use std::hash::{BuildHasherDefault, Hash};
 
 use indexmap::IndexSet;
-use rgb::{alt::Gray, ComponentMap, ComponentSlice, FromSlice, RGB, RGBA};
+use rgb::{ComponentMap, FromSlice, RGB, RGBA, alt::Gray};
 use rustc_hash::FxHasher;
 
 use crate::{
@@ -49,39 +49,39 @@ pub fn reduced_to_indexed(png: &PngImage, allow_grayscale: bool) -> Option<PngIm
     let mut raw_data = Vec::with_capacity(png.data.len() / png.channels_per_pixel());
     let palette: Vec<_> = match png.ihdr.color_type {
         ColorType::Grayscale { transparent_shade } => {
-            let pmap = build_palette(png.data.as_gray().iter().cloned(), &mut raw_data)?;
+            let pmap = build_palette(png.data.as_gray().iter().copied(), &mut raw_data)?;
             // Convert the Gray16 transparency to Gray8
             let transparency_pixel = transparent_shade.map(|t| Gray::from(t as u8));
             pmap.into_iter()
                 .map(|px| {
-                    RGB::from(px).alpha(if Some(px) != transparency_pixel {
+                    RGB::from(px).with_alpha(if Some(px) == transparency_pixel {
-                        255
-                    } else {
                         0
+                    } else {
+                        255
                     })
                 })
                 .collect()
         }
         ColorType::RGB { transparent_color } => {
-            let pmap = build_palette(png.data.as_rgb().iter().cloned(), &mut raw_data)?;
+            let pmap = build_palette(png.data.as_rgb().iter().copied(), &mut raw_data)?;
             // Convert the RGB16 transparency to RGB8
             let transparency_pixel = transparent_color.map(|t| t.map(|c| c as u8));
             pmap.into_iter()
                 .map(|px| {
-                    px.alpha(if Some(px) != transparency_pixel {
+                    px.with_alpha(if Some(px) == transparency_pixel {
-                        255
-                    } else {
                         0
+                    } else {
+                        255
                     })
                 })
                 .collect()
         }
         ColorType::GrayscaleAlpha => {
-            let pmap = build_palette(png.data.as_gray_alpha().iter().cloned(), &mut raw_data)?;
+            let pmap = build_palette(png.data.as_gray_alpha().iter().copied(), &mut raw_data)?;
             pmap.into_iter().map(RGBA::from).collect()
         }
         ColorType::RGBA => {
-            let pmap = build_palette(png.data.as_rgba().iter().cloned(), &mut raw_data)?;
+            let pmap = build_palette(png.data.as_rgba().iter().copied(), &mut raw_data)?;
             pmap.into_iter().collect()
         }
         _ => return None,
@@ -106,7 +106,7 @@ pub fn reduced_rgb_to_grayscale(png: &PngImage) -> Option<PngImage> {
     let byte_depth = png.bytes_per_channel();
     let bpp = png.channels_per_pixel() * byte_depth;
     let last_color = 2 * byte_depth;
-    for pixel in png.data.chunks(bpp) {
+    for pixel in png.data.chunks_exact(bpp) {
         if byte_depth == 1 {
             if pixel[0] != pixel[1] || pixel[1] != pixel[2] {
                 return None;
@@ -138,15 +138,30 @@ pub fn reduced_rgb_to_grayscale(png: &PngImage) -> Option<PngImage> {
 
 /// Attempt to convert indexed to a different color type, returning the resulting image if successful
 #[must_use]
-pub fn indexed_to_channels(png: &PngImage, allow_grayscale: bool) -> Option<PngImage> {
+pub fn indexed_to_channels(
+    png: &PngImage,
+    allow_grayscale: bool,
+    optimize_alpha: bool,
+) -> Option<PngImage> {
     if png.ihdr.bit_depth != BitDepth::Eight {
         return None;
     }
-    let palette = match &png.ihdr.color_type {
+    let mut palette = match &png.ihdr.color_type {
-        ColorType::Indexed { palette } => palette,
+        ColorType::Indexed { palette } => palette.clone(),
         _ => return None,
     };
 
+    // Ensure fully transparent colors are black, which can help with grayscale conversion
+    if optimize_alpha {
+        for color in &mut palette {
+            if color.a == 0 {
+                color.r = 0;
+                color.g = 0;
+                color.b = 0;
+            }
+        }
+    }
+
     // Determine which channels are required
     let is_gray = if allow_grayscale {
         palette.iter().all(|c| c.r == c.g && c.g == c.b)
@@ -178,7 +193,7 @@ pub fn indexed_to_channels(png: &PngImage, allow_grayscale: bool) -> Option<PngI
     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_slice()[ch_start..=ch_end]);
+        data.extend_from_slice(&color.as_ref()[ch_start..=ch_end]);
     }
 
     Some(PngImage {

src/reduction/mod.rs

@@ -1,6 +1,6 @@
 use std::sync::Arc;
 
-use crate::{evaluate::Evaluator, png::PngImage, ColorType, Deadline, Deflaters, Options};
+use crate::{ColorType, Deadline, Deflater, Options, evaluate::Evaluator, png::PngImage};
 
 pub mod alpha;
 use crate::alpha::*;
@@ -21,8 +21,8 @@ pub(crate) fn perform_reductions(
 
     // 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.deflate {
+    let cheap = match opts.deflater {
-        Deflaters::Libdeflater { compression } => compression < 12 && opts.fast_evaluation,
+        Deflater::Libdeflater { compression } => compression < 12 && opts.fast_evaluation,
         _ => false,
     };
 
@@ -106,7 +106,9 @@ pub(crate) fn perform_reductions(
     // 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) {
+        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;
@@ -116,7 +118,7 @@ pub(crate) fn perform_reductions(
     // 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 && !deadline.passed() {
+    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));
@@ -181,7 +183,7 @@ pub(crate) fn perform_reductions(
         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().map_or(true, |r| r.data != indexed.data) {
+                if reduced.as_ref().is_none_or(|r| r.data != indexed.data) {
                     eval.try_image(Arc::new(indexed));
                     evaluation_added = true;
                 }

src/reduction/palette.rs

@@ -4,8 +4,7 @@ use rgb::RGBA8;
 use crate::{
     colors::{BitDepth, ColorType},
     headers::IhdrData,
-    png::{scan_lines::ScanLine, PngImage},
+    png::{PngImage, scan_lines::ScanLine},
-    Interlacing,
 };
 
 /// Attempt to reduce the number of colors in the palette, returning the reduced image if successful
@@ -87,7 +86,7 @@ pub fn sorted_palette(png: &PngImage) -> Option<PngImage> {
     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 = enumerated.remove(keep_first);
+    let first = keep_first.map(|f| enumerated.remove(f));
 
     // Sort the palette
     enumerated.sort_by(|a, b| {
@@ -104,7 +103,9 @@ pub fn sorted_palette(png: &PngImage) -> Option<PngImage> {
         };
         color_val(a.1).cmp(&color_val(b.1))
     });
-    enumerated.insert(0, first);
+    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();
@@ -132,7 +133,7 @@ pub fn sorted_palette(png: &PngImage) -> Option<PngImage> {
 #[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 != Interlacing::None {
+    if png.ihdr.bit_depth != BitDepth::Eight || png.ihdr.interlaced {
         return None;
     }
     let palette = match &png.ihdr.color_type {
@@ -154,7 +155,7 @@ pub fn sorted_palette_mzeng(png: &PngImage) -> Option<PngImage> {
 #[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 != Interlacing::None {
+    if png.ihdr.bit_depth != BitDepth::Eight || png.ihdr.interlaced {
         return None;
     }
     let palette = match &png.ihdr.color_type {
@@ -204,27 +205,31 @@ fn apply_palette_reorder(png: &PngImage, remapping: &[usize]) -> Option<PngImage
 }
 
 // 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) -> usize {
+fn most_popular_edge_color(num_colors: usize, png: &PngImage) -> Option<usize> {
-    let mut counts = [0u32; 256];
+    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;
         }
     }
-    counts
+    let max = counts
         .iter()
-        .copied()
         .take(num_colors)
         .enumerate()
         .max_by_key(|&(_, v)| v)
-        .unwrap_or_default()
+        .unwrap();
-        .0
+    // 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 = [0u32; 256];
+    let mut counts = [0_u32; 256];
     for &val in &png.data {
         counts[val as usize] += 1;
     }
@@ -256,7 +261,7 @@ fn apply_most_popular_color(png: &PngImage, remapping: &mut [usize]) {
 
 // Calculate co-occurences matrix
 fn co_occurrence_matrix(num_colors: usize, png: &PngImage) -> Vec<Vec<u32>> {
-    let mut matrix = vec![vec![0u32; num_colors]; num_colors];
+    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) {
@@ -278,7 +283,7 @@ fn co_occurrence_matrix(num_colors: usize, png: &PngImage) -> Vec<Vec<u32>> {
                 matrix[val][prev_val] += 1;
             }
         }
-        prev = Some(line)
+        prev = Some(line);
     }
     matrix
 }

src/sanity_checks.rs

@@ -1,6 +1,10 @@
+use std::io::Cursor;
+
 use image::{codecs::png::PngDecoder, *};
 use log::{error, warn};
-use std::io::Cursor;
+
+#[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 {
@@ -40,7 +44,7 @@ fn load_png_image_from_memory(png_data: &[u8]) -> Result<Vec<RgbaImage>, image::
         decoder
             .apng()?
             .into_frames()
-            .map(|f| f.map(|f| f.into_buffer()))
+            .map(|f| f.map(image::Frame::into_buffer))
             .collect()
     } else {
         DynamicImage::from_decoder(decoder).map(|i| vec![i.into_rgba8()])

tests/alpha.rs

@@ -0,0 +1,346 @@
+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,
+    );
+}