optipng を Homebrew でインストール

プロジェクトリンク

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• optipng

プロジェクトの歴史

Cosmin Truta introduced OptiPNG on 2001-12-10 as a PNG IDAT recompression tool that repeatedly tried zlib compression and strategy levels together with PNG delta filters. Version 0.3, announced on 2003-02-24, was the first public release and added documentation, many user options, lossless image-type reduction, zlib memory-level iteration, and lower-memory IDAT handling.

The early 0.x series steadily expanded from pure PNG recompression into a practical asset-pipeline utility. Version 0.5 added support for external input formats BMP, GIF, and PNM in 2006; version 0.5.3 added basic TIFF import; version 0.6 added compressed BMP support, APNG safety behavior, and recovery for incomplete IDAT data.

Later releases were shaped as much by security and dependency maintenance as by compression features. The history records repeated libpng and zlib upgrades, parser fixes for GIF, TIFF, and BMP handling, build-system modernization, and, in 2025, the jump from 0.7.9 to 7.9.1 with CMake support and an AsciiDoc manual.

採用の歴史

OptiPNG became one of the standard lossless PNG optimizers distributed by operating-system package managers. The input metadata lists packages across Alpine, Homebrew, Chocolatey, Debian, Fedora, MacPorts, Nix, Arch, Scoop, Ubuntu, winget, and openSUSE, reflecting its role as a common build and release dependency rather than a single-platform image utility.

使われ方

Developers and designers use `optipng` to shrink PNG assets for websites, applications, documentation, and release bundles while preserving image content. The tool matters in automated pipelines because it is a deterministic CLI: pass files in, choose an optimization level or output location, and receive optimized PNGs suitable for version-controlled assets or packaging.

The underlying PNG optimization problem is subtle: PNG size depends on color type reductions, palette reductions, row filters, zlib strategy, and Huffman-buffer behavior. OptiPNG's package value is that it automates repeated trials over that search space, giving build systems a boring command instead of bespoke compression experiments.

パッケージ好きにとっての重要性

OptiPNG is a classic package-nerd utility: small, C-based, dependency-sensitive, and useful precisely because package ecosystems can put it everywhere. Its revision history is a miniature tour of real-world file-format tooling, where security fixes in image parsers and updates to bundled compression libraries are as important as byte savings.

タイムライン

• 2001-12-10: OptiPNG is introduced.
• 2003-02-24: Version 0.3 is announced as the first public release.
• 2006-01-14: Version 0.5 adds BMP, GIF, and PNM input support.
• 2008-06-15: Version 0.6 adds compressed BMP support, APNG handling safeguards, and incomplete-IDAT recovery.
• 2017-12-27: Version 0.7.7 fixes GIF and TIFF decoder vulnerabilities and updates libpng and zlib.
• 2025-05-20: Version 7.9.1 updates libpng, enables SIMD-optimized libpng builds on selected platforms, adds CMake, and rewrites the manual.

Related projects

• OptiPNG sits beside other PNG optimizers such as pngcrush and depends conceptually on the PNG format, Deflate, zlib, and libpng. Its own PNG-Tech article explains the filter, reduction, and zlib-strategy space that these tools explore.

ソース

• https://formulae.brew.sh/formula/optipng
• https://optipng.sourceforge.net/
• https://optipng.sourceforge.net/history.txt
• https://optipng.sourceforge.net/optipng-7.9.1.man1.html
• https://optipng.sourceforge.net/pngtech/optipng.html