Bundled with PrusaSlicer: commit 6c0831f91ffde5dfe2ceef32cbaff91d62b0e0ee Original README follows:

QOI - The “Quite OK Image Format” for fast, lossless image compression

Single-file MIT licensed library for C/C++

See qoi.h for the documentation and format specification.

More info at https://qoiformat.org

Why?

Compared to stb_image and stb_image_write QOI offers 20x-50x faster encoding, 3x-4x faster decoding and 20% better compression. It's also stupidly simple and fits in about 300 lines of C.

Example Usage

• qoiconv.c converts between png <> qoi
• qoibench.c a simple wrapper to benchmark stbi, libpng and qoi

Limitations

The QOI file format allows for huge images with up to 18 exa-pixels. A streaming en-/decoder can handle these with minimal RAM requirements, assuming there is enough storage space.

This particular implementation of QOI however is limited to images with a maximum size of 400 million pixels. It will safely refuse to en-/decode anything larger than that. This is not a streaming en-/decoder. It loads the whole image file into RAM before doing any work and is not extensively optimized for performance (but it's still very fast).

If this is a limitation for your use case, please look into any of the other implementations listed below.

Tools

• https://github.com/floooh/qoiview - native QOI viewer
• https://github.com/pfusik/qoi-ci/releases/tag/qoi-ci-1.1.0 - QOI Plugin installer for GIMP, Imagine, Paint.NET and XnView MP
• https://github.com/iOrange/QoiFileTypeNet/releases/tag/v0.2 - QOI Plugin for Paint.NET
• https://github.com/iOrange/QOIThumbnailProvider - Add thumbnails for QOI images in Windows Explorer
• https://github.com/Tom94/tev - another native QOI viewer (allows pixel peeping and comparison with other image formats)
• https://apps.apple.com/br/app/qoiconverterx/id1602159820 QOI <=> PNG converter available on the Mac App Store
• https://github.com/kaetemi/qoi-max - QOI Bitmap I/O Plugin for 3ds Max
• https://raylibtech.itch.io/rtexviewer - texture viewer, supports QOI

Implementations & Bindings of QOI

• https://github.com/pfusik/qoi-ci (Ć, transpiled to C, C++, C#, Java, JavaScript, Python and Swift)
• https://github.com/kodonnell/qoi (Python)
• https://github.com/Cr4xy/lua-qoi (Lua)
• https://github.com/superzazu/SDL_QOI (C, SDL2 bindings)
• https://github.com/saharNooby/qoi-java (Java)
• https://github.com/MasterQ32/zig-qoi (Zig)
• https://github.com/rbino/qoix (Elixir)
• https://github.com/NUlliiON/QoiSharp (C#)
• https://github.com/aldanor/qoi-rust (Rust)
• https://github.com/zakarumych/rapid-qoi (Rust)
• https://github.com/takeyourhatoff/qoi (Go)
• https://github.com/DosWorld/pasqoi (Pascal)
• https://github.com/elihwyma/Swift-QOI (Swift)
• https://github.com/xfmoulet/qoi (Go)
• https://erratique.ch/software/qoic (OCaml)
• https://github.com/arian/go-qoi (Go)
• https://github.com/kchapelier/qoijs (JavaScript)
• https://github.com/KristofferC/QOI.jl (Julia)
• https://github.com/shadowMitia/libqoi/ (C++)
• https://github.com/MKCG/php-qoi (PHP)
• https://github.com/LightHouseSoftware/qoiformats (D)
• https://github.com/mhoward540/qoi-nim (Nim)

QOI Support in Other Software

• SerenityOS supports decoding QOI system wide through a custom cpp implementation in LibGfx
• Raylib supports decoding and encoding QOI textures through its rtextures module
• Rebol3 supports decoding and encoding QOI using a native codec
• c-ray supports QOI natively
• SAIL image decoding library, supports decoding and encoding QOI images
• Orx 2D game engine, supports QOI natively

Packages

AUR - system-wide qoi.h, qoiconv and qoibench install as split packages.

Implementations not yet conforming to the final specification

These implementations are based on the pre-release version of QOI. Resulting files are not compatible with the current version.

• https://github.com/ChevyRay/qoi_rs (Rust)
• https://github.com/panzi/jsqoi (TypeScript)
• https://github.com/0xd34df00d/hsqoi (Haskell)