Frame 0 uses more than 256 color indexes

[redserpent7]

I am not sure how or why this is happening. I am loading an existing Gif, resizing it one frame at a time with Jimp and then saving the output gif in a file.

I am not sure at which point or why the palette changes since my source image is indeed a GIF.

This is my code:

GifUtil.read("org.gif").then(inputGif => {
    images = [];
    
	for (var frame = 0; frame<inputGif.frames.length; frame++){
		var j = new Jimp(inputGif.frames[frame].bitmap.width, inputGif.frames[frame].bitmap.height , 0);
        j.bitmap.data = inputGif.frames[frame].bitmap.data;
        j.resize(width, height);
       
        images[frame] = new GifFrame(j.bitmap);
    }

    inputGif.frames = images;
   

    return GifUtil.write("modified.gif", inputGif.frames, inputGif).then(outputGif => {
        console.log("modified");
    });
});

How do I prevent it from up-scaling the color palette? or how can I quantize the frame?

[jtlapp]

Please ping me again next week, unless you resolve this on your own. I'm in the middle of moving, don't have time to investigate. Sorry about that!

[jtlapp]

Oh, Jimp add colors when resizing. Call one of the quantize*() methods to reduce the number of colors again.

[redserpent7]

Oh I never saw the quantize methods. thanks.

[DeanVanGreunen]

@redserpent7 I have a similar issue here could you assist please?

[oluSammy]

@redserpent7 pls how did you used the quantize method

[DeanVanGreunen]

@oluSammy take a look at my code, taken from my live production server. it simply does the following

1. load gif file
2. extract frames from the gif
3. edit each gif frame
4. quantize the frame
5. append the frame to a new frame list
6. write frames to output file

// Helper functions
async function getGifFrames(file) {
  return new Promise((resolve) => {
    GifUtil.read(file).then((inputGif) => {
      resolve(inputGif.frames);
    });
  });
}


// Sample Code

let frames = []; // store new edited frames
let gif_frames = await getGifFrames("myImage.gif"); // get the frames from an existing GiF

gif_frames.forEach((frame) => {
 let newFrame = editFrame(frame); // edit frame here
 GifUtil.quantizeDekker(newFrame); // quantize the image
 frames.push(new GifFrame(new BitmapImage(image.bitmap))); // push frame to new frame list
});

// do something with the frame list like saving to disc
GifUtil.write("outputImage.gif", frames);