Transparent animated gif re-encoding and re-quantization

[lilith]

For my use case in Imageflow, I want to support round-tripping transparent (background+delta) animated gifs (while doing operations like resizing/etc on them in 32-bit BGRA mode and then re-quantizing). I see a dispose_only method that mentions this case, but no examples. I'm currently migrating my custom fork of dispose/gif to use your crates, and was wondering if you have any examples of this kind of task.

[kornelski]

See gifski for example usage.

https://github.com/ImageOptim/gifski/blob/b3946398cea3999c77be50880bdc5692d53bd178/src/lib.rs#L810-L823

After dispose_only() the image is the exact canvas that the next frame will be painted on, so it can be used to find minimum difference between the canvas and the next full frame. This can be more precise than tracking of "dirty" rectangles.