Overlapping frames in animated GIF and PNG

[doublex]

This image:

Testcase (frame is interleaved - tested with PIL7 and PIL8):

import PIL.Image
imageObject = PIL.Image.open("/tmp/98246874-2e18a800-1f73-11eb-8583-f2c1f7d293f0.gif")
imageObject.seek(5)
imageObject.seek(6)
imageObject.seek(7)
imageObject.show() 

[doublex]

Expected result:

PIL frame:

[doublex]

Also APNG images won't load properly:

[radarhere]

For the record, the animated PNG you have just attached shows this when the code from your first post is run.

[doublex]

Yes, there are bugs decoding AnimGIFs and APNGs (GIF is nastier).
imagemagick decodes the frame to:

[stevemcgf]

I only see the issue with APNG files not with GIF.

[stevemcgf]

Animated PNG

Incorrect render of 2nd frame

Fixed render of 2nd frame (using code in pull request)

[doublex]

@stevemcgf

AnimGIF renders wrong (at least for me using pillow 8.0.1).
Steps to reproduce:

wget https://user-images.githubusercontent.com/274624/98246874-2e18a800-1f73-11eb-8583-f2c1f7d293f0.gif

import PIL.Image
image = PIL.Image.open("/tmp/98246874-2e18a800-1f73-11eb-8583-f2c1f7d293f0.gif")
for frame in PIL.ImageSequence.Iterator(image):
    last_frame = frame
last_frame.show()

[radarhere]

The GIF part of this should be resolved by #5125

[radarhere]

I've created PR #5126 to resolve the APNG part of this, as an alternative to #5071

[radarhere]

The GIF part of this should be fixed in Pillow 8.1.0, due to be released on January 2.

[doublex]

Thanks for the effort!

[radarhere]

The APNG part of this should now also be fixed in Pillow 8.1.0

[doublex]

@radarhere
Thanks again for your efforts!