Gif image copyCrop not working properly

[longpp1994]

version: 4.1.3

void cropAndSaveImage({
  required int x,
  required int y,
  required int width,
  required int height,
  required String savePath,
  required String imagePath,
}) {
  final image = decodeImage(File(imagePath).readAsBytesSync());

  final cropImg = copyCrop(
    image!,
    x: x,
    y: y,
    width: width,
    height: height,
  );

  final file = File(savePath);
  file.createSync(recursive: true);
  file.writeAsBytesSync(encodeGif(cropImg));
}

origin gif

output gif

It happens on some gif images，maybe it has something to do with the palette?

[brendan-duncan]

Does it happen without the copyCrop?
GIF is a horrible format, I wish it had died in the 90s like it was supposed to. Likely it's a per-frame palette issue. I had dome some work around that, but it looks like this is another edge case. I'll take a look whenever I can get a chance.

[longpp1994]

I made a test， It looks like copyCrop is not the cause of that
btw i agree with your point on GIF XD

void decodeThenEncodeGif({
  required String imagePath,
  required String savePath,
}) {
  final image = decodeImage(File(imagePath).readAsBytesSync());
  final file = File(savePath);
  file.createSync(recursive: true);
  file.writeAsBytesSync(encodeGif(image!));
}

output: