gif-renderer

This is a GIF file decoder written in Rust, compatible to both 87a and 89a GIF versions.

This tool should work as expected on Linux, Windows and macOS. Other platforms might be supported. The most platform-sensitive code is on the rendering side: This tool relies on the glutin crate for OpenGL context creation and the gl crate for openGL bindings.

Please note that it needs nightly Rust to be built, as it make use of the vec_into_raw_parts feature.

How to use it?

After building it (the most straightforward way being to use Cargo here), you can use the resulting binary to display a GIF image by adding its path as argument:

gif-renderer images/some-gif-file.gif

Is it finished? Can I use this?

Yes!

The huge majority of valid GIF files will be fully-rendered instantly. Rarely encountered features like interlacing or the "restore to previous" disposal method should be well managed.

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The only feature which has not been implemented is the "Plain Text Extension". When encountered, this extension is just ignored. This is because this feature is very (VERY) rarely used and is pretty hard to implement from scratch. As I encountered no GIF besides Plain Text Extension demos, with that feature, and that not even web browsers seem to handle it well, I figured it was the sensible thing to do to ignore it.

What's left to do?

This tool works well and is pretty fast, but there is still some room for improvement:

• The Plain Text Extension could be completely handled.

• For now we render each frame once it has been completely decoded. Another mode could be to be able to progressively display each pixels as they are being decoded. This would very rarely be better than the current situation (I would even guess worst in most cases) though, and might only be useful when either file access or LZW decoding is remarkably slow.

• Some errors could be ignored (e.g. ignoring when too much color data is found instead of exiting) and logged.