Quantize colors from a RGB(A) buffer.

[srijan-paul]

(I'd be happy to contribute this feature if PRs are welcome).

Currently, we have to set the global/local color table manually.
However, when writing an RGBA buffer, it would be much easier if the library could quantize the colors into a 256-bit space.

GIFLIB, for example, has a GifQuantizeColors function that is very handy for creating frame-local color tables.

[dloebl]

Hi @srijan-paul. Great feature request! We are working on a cgif_rgb API in #37 that will support color quantization and dithering. It's still work-in-progress, but feel free to give it a try. You can find an example here: cgif_rgb_example.c. The current limitations are listed in the pull request.
We hope to be able to release this feature in the coming months.

[srijan-paul]

Amazing, thank you for working on this.
Is the quantization implementation currently usable? I'm using cgif for an app I'm working on.
For now, I think I'll manually quantize the RGBA buffer if rgb API isn't ready yet.

[dloebl]

@srijan-paul The RGB API isn't released so it's still unstable. It should still work though the file size of the resulting GIFs won't be ideal: As of now, it creates one local color palette per frame. In the future we are planning to support quantizing to a single global color palette as well.

[srijan-paul]

Got it.
I implemented my own quantizer for now, and am happy with the results.
Looking forward to more options :^)