Animated GIF bugs

[tom]

Hi Devil team,

I found error when calling ilConvertImage(IL_RGBA, IL_UNSIGNED_BYTE) for animated gif files. It seems that this problem occurs since version 1.7.3 (1.7.2 works). Test source:

int main(int argc, char* argv[])
{
    ILuint imageId;
    ILboolean success;
   
    if(argc < 2)
    {
        printf("no file\n");
        return -1;
    }

    ilInit();
    ilGenImages(1, &imageId);
    ilBindImage(imageId);
    success = ilLoadImage(argv[1]);
    if(!success)
    {
        printf("error while openning file\n");
        return -1;
    }
   
    success = ilConvertImage(IL_RGBA, IL_UNSIGNED_BYTE);
    if(!success)
    {
        printf("error while converting image\n");
        return -1;
    }
...

Otherwise, saving all images of the animation in separate png files (using ilActiveImage and ilSave(IL_PNG, ...)) works well but resulting files are bad. I found this problem only for optimized GIF files (if they use transparency to avoid duplication of similar part of the image).

When i've enough time, i will try to find more details (or fix) to help you debugging this problem.

Thanks,

Tom

[Denton Woods]

Do you have an example GIF that this fails on?

[tom]

you can try with this one :

http://upload.wikimedia.org/wikipedia/commons/d/d3/Newtons_cradle_animation_book_2.gif

[Denton Woods]

Okay, I think I found the source of the problem.  One was in ilConvertImage when it converts the palette.  Another was in the GIF-loading code where the x and y offsets were not being properly applied for a frame.  The version in CVS is able to load the Newton's cradle image just fine now.

[tom]

Good ! i will try it, thanks !