Fix incorrect dealing with offset sub-frames #18
Merged
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gifwrap fails to correctly decode
test/fixtures/rnaples-offsets-public.gif
included in its tests. I threw together a simple test that combines all frames into one image with Jimp.Erroneous results:
Expected results (after applying fix):
omggif's
decodeAndBlitFrameRGBA
blits the entire frame, not just the sub-region, so, in order to keep the GifCode API the same, we must contract the buffer, skipping all of the empty space.An alternative solution would be to simply set
info.[width/height] = reader.[width/height]; info.[x/y] = 0
, which would be slightly faster in here (but cause clients to be slower, as they have to blend the whole image).Better yet would be to fix omggif (or use a different library) to allow returning just the sub-section, however I looked into decodeAndblitFrameRGBA and it gets pretty complicated due to interlacing and stuff.
But, for a quick fix, this'll do.