refract | guided AVIF/JPEG XL/WebP conversion utility

refract is a Rust library. refract has no bugs, it has no vulnerabilities, it has a Permissive License and it has low support. You can download it from GitHub.

Refract is a guided image conversion tool written in Rust for x86-64 Linux systems with GTK. It takes JPEG and PNG image sources and produces AVIF, JPEG XL, and WebP clones. The program is named after — and works like — eye doctor Refraction Tests. It generates candidate images at various qualities, asking at each step how it looks, and uses the feedback (you provide) to arrive at the smallest possible "acceptable" output. The beauty of this approach is that it moots the need for exhaustive testing. Refract's quality stepping works by selecting the mid-point between moving min/max boundaries. Each answer you provide adjusts the range, allowing the final, perfect result to be discovered in just 5-10 steps instead of 100+.