I don't know if this is a bug in the mangen but it seems to require
explicitly setting the value name to display correctly.
Before:
```
--zi [default: 15]
Set the number of iterations to use for Zopfli compression.
```
After:
```
--zi=iterations [default: 15]
Set the number of iterations to use for Zopfli compression.
```
This does not affect MANUAL.txt or the built-in help.
#648 may have been a bit hasty - I realised afterward that there's a
simpler way to achieve the same thing, and include the Brute filter as
well.
This reverts #648 and instead just picks None up front if the line is
all zeros. This is guaranteed to be the chosen filter for MinSum,
Entropy, Bigrams and BigEnt. It's almost certainly true for Brute as
well but this is harder to prove. I've tested this across hundreds of
images and found no change in output.
Allow the creation of PNGs with uncompressed deflate streams via level 0
of libdeflate. If you want a glorified BMP with delta filters, this
change will make your dreams come true 🙂.
This PR extends the `--zopfli` argument with an optional iteration
count. In my case, I have a bunch of very small images (a few kB or
less), and I often like to use hundreds of iterations to squeeze off the
last several bytes. (I know that this crate isn't intended for
brute-force optimization, but I've found that some of its
transformations and filter strategies can be more creative than
`zopflipng`.) But this is also useful in the opposite direction, for
allowing Zopfli compression on large images where 15 iterations would be
prohibitive.
I have identified two potential improvements for how we perform static analysis
on our code in our CI pipeline:
- The `giraffate/clippy-action` we currently use has not been updated to Node
20, and GitHub has repeatedly indicated that they will phase out actions that
do not support the latest Node versions. Despite my efforts to help with the
update by submitting a pull request upstream, it has been ignored for months
despite its perceived ease of review, raising concerns about the ongoing
maintenance of the action. This situation suggests we should explore
alternative methods for integrating Clippy with GitHub's UI.
- As evidenced by PR 632, thoroughly testing Rust crates for every possible
feature combination is often overlooked due to the tedious nature of the task.
Our current CI setup only checks two feature combinations, which is far from
comprehensive.
To address the first improvement, these changes drop `clippy-action` entirely in
favor of utilizing GitHub's native CodeQL SARIF (Static Analysis Results
Interchange Format) file integration. Since Clippy cannot directly output lints
in SARIF, `clippy-sarif` is used to convert Clippy's JSON output to SARIF.
Additionally, `sarif-fmt` is added to turn SARIF into a human-friendly display
format in the workflow run logs.
For the second improvement, let's use `cargo hack` with the `--feature-powerset`
flag to run Clippy for every possible feature combination. This approach strikes
a good balance between CI runtime and thoroughness, as the number of feature
combinations grows superlinearly with the number of features: running `cargo
nextest` for every powerset element would lead to excessively long CI times.
Fixes#619.
Interlacing still defaults to 0 when `--nx` is not specified and can
still be explicitly set even if it is (e.g. `-i 0 --nx` will still
deinterlace).
This PR adds the modified zeng ("mzeng") palette sorting method, in
addition to the existing luma and battiato methods. Speed is very
similar to the battiato method with slightly better results on average.
Resulting sizes from two different image sets (all indexed or able to be
indexed):
| | master | PR |
|-|-|-|
| Set 1 | 29,647,156 | 29,555,697 |
| Set 2 | 23,732,133 | 23,570,862 |
Additionally, I've added a new "first colour" heuristic for both the
mzeng and battiato methods: We use the most popular colour overall, but
only if it covers at least 15% of the image. This provided 13k savings
on Set 2 vs the edge colour heuristic (which is still used in the luma
sort).
This PR adds a build script to generate a man page using clap_mangen, as
per this example:
https://github.com/sondr3/clap-man-example/blob/main/build.rs
I'm not sure what to actually do with the man file from here, I guess
it's up to the packaging process to do something with it?
See
https://github.com/shssoichiro/oxipng/issues/69#issuecomment-1963352536
Note I couldn't see a way to include the `DISPLAY` chunk names from the
constant as we did before. They're now just hardcoded into the help and
will require manually updating if the list changes.
Closes#526
---------
Co-authored-by: Alejandro González <me@alegon.dev>
The filters used during reduction evaluations are normally set to None &
Bigrams, regardless of any options. This PR makes a slight change so
that if only one filter is specified in the options, this filter will be
used for reduction evaluations too.
This resolves an odd situation affecting lower levels (when --fast is
enabled) where you may try to force the filter to a specific value but
it actually ends up different because a reduction evaluation was
smaller. It's particularly helpful if you're wanting it to be as fast as
possible by using `-o0 -f0` which will now exclusively use None instead
of trying the slower Bigrams as well.
As another use, you could try to brute force oxipng by iterating each
filter separately, though this may not actually achieve anything 😂
[edit] I also pulled the options out into a separate file, though this
wasn't relevant to the filter change.
This is a minor change that allows using both `--strip` and `--keep` at
the same time.
E.g. `--strip safe --keep eXIf` will strip chunks while preserving both
the ones that aren't "safe" to remove *and* eXIf. Essentially it's a
convenience to allow extending the default list used by `--strip safe`.
Specifying chunk names for both options is not permitted, e.g. `--strip
eXIf --keep eXIf` will error.
Use of `--strip all` with `--keep` is redundant, but is permitted.
A detailed read to the [Rust documentation for the `fs::Permissions`
struct](https://doc.rust-lang.org/stable/std/fs/struct.Permissions.html)
and a little digging into its implementation in the standard library
have shown that this code didn't work as expected in any platform, and
was a bit weird to begin with:
- It first read the permissions from the input file metadata.
- Then it fetched the output file metadata.
- After that, it changed the permissions for that output file metadata.
- It then performed a sanity check that the output file had the expected
permissions.
Barring the fact that the sanity check in step 4 is not needed, the
overall approach is wrong because setting the permissions in a file
metadata struct does not actually persist those changes anywere; it's
just an in-memory change only, so these operations were useless. The
Rust documentation explicitly mentions that the `set_readonly` method
"does not modify the files attributes" [sic], but it's easy to miss that
warning and not realize that it also applies to the methods offered by
the `PermissionsExt` trait. The code only appeared to work because in
most cases the default permissions for new files happen to match the
input file permissions, so the sanity check passed.
To fix this, use the `set_permissions` method on `File` to actually set
the output file permissions to be the same as the input file
permissions, which is both much simpler and robust.
These changes were tested in the context of issue #576, and fix#576.
This PR brings a big overhaul to oxipng's help, with new long form
descriptions of many options.
The full output (--help) is added as a text file MANUAL.txt. Critiques
welcome.
The short output (-h) is simplified and appears as follows:
```
Losslessly improve compression of PNG files
Usage: oxipng [OPTIONS] <files>...
Arguments:
<files>... File(s) to compress (use '-' for stdin)
Options:
-o, --opt <level> Optimization level (0-6, or max) [default: 2]
-r, --recursive Recurse input directories, optimizing all PNG files
--dir <directory> Write output file(s) to <directory>
--out <file> Write output file to <file>
--stdout Write output to stdout
-p, --preserve Preserve file permissions and timestamps if possible
-P, --pretend Do not write any files, only show compression results
-s Strip safely-removable chunks, same as '--strip safe'
--strip <mode> Strip metadata (safe, all, or comma-separated list)
CAUTION: 'all' will convert APNGs to standard PNGs
--keep <list> Strip all metadata except in the comma-separated list
-a, --alpha Perform additional alpha channel optimization
-i, --interlace <type> Set PNG interlacing type (0, 1, keep) [default: 0]
--scale16 Forcibly reduce 16-bit images to 8-bit (lossy)
-v, --verbose... Run in verbose mode (use twice to increase verbosity)
-q, --quiet Run in quiet mode
-f, --filters <list> Filters to try (0-9; see '--help' for details)
--fast Use fast filter evaluation
--zc <level> Deflate compression level (1-12)
--nb Do not change bit depth
--nc Do not change color type
--np Do not change color palette
--ng Do not change to or from grayscale
--nx Do not perform any transformations
--nz Do not recompress unless transformations occur
--fix Disable checksum validation
--force Write the output even if it is larger than the input
-Z, --zopfli Use the much slower but stronger Zopfli compressor
--timeout <secs> Maximum amount of time to spend on optimizations
-t, --threads <num> Set number of threads to use [default: num CPU cores]
-h, --help Print help (see more with '--help')
-V, --version Print version
Run `oxipng --help` to see full details of all options
```
---------
Co-authored-by: Alejandro González <me@alegon.dev>
This update brings several parameterization and usage flexibility
improvements on Zopfli, allowing users to choose to limit execution time
by a number of iterations without improvement, and exposing a more
advanced `ZlibEncoder` struct to tune compression block sizes and
DEFLATE block types. Some minor microoptimizations were also made.
For now, I don't expect this PR to substantially affect how OxiPNG
compresses images using its Zopfli mode, but the additional parameter
customization may come in handy for future work improving how Zopfli is
used in OxiPNG.
Tidy up the API by removing a couple of options we don't really need.
Backup was discussed in #542
Check was discussed in #439
@shssoichiro Just say if you prefer to keep either of these 🙂
