Enable Codec_GifInterlacedTruncated test for Wuffs
A recent update to the Wuffs version that Skia uses means that the test
now passes.
While the old third_party/gif implementation and the Wuffs
implementation now both replicate interlaced rows (what the old
implementation calls a "Haeberli hack"), and the
Codec_GifInterlacedTruncated test passes either way, the exact
replication algorithm is different. In general, pixel-by-pixel output
may be different for the same (truncated) input.
For example, the old implementation only processed input on block
boundaries. If the truncation happened within a block, the old
implementation produces no output for that partial block but the Wuffs
implementation does.
Also, the old implementation used the interlaced row as the *center* of
the extrapolation (the 'broad brush'); Wuffs uses it as the *top* of the
extrapolation. There are subjective arguments (e.g. 'Venetian blinds',
'fat bottom rows') for either behavior. In any case, it isn't covered by
the GIF spec.
Bug: skia:8235
Bug: skia:8766
Change-Id: Ia8d8b1007006697498e47ec6bba7be7d81be10c4
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/243596
Commit-Queue: Leon Scroggins <scroggo@google.com>
Reviewed-by: Leon Scroggins <scroggo@google.com>
1 file changed