This stems from a behavior difference between Skia and Chrome.
In Skia, we want to write transparent pixels as often as possible.
(It's faster than checking if we should skip each pixel.)
In Chrome, they avoid writing transparent pixels unless
absolutely necessary.
We were cautious about changing behavior when this first landed,
but this is easier to think about in a smaller change (right now).
(1) We can always write transparent pixels when we are writing
an independent frame.
(2) There is no need for the progressiveDisplay() check. We
only ever use progressive display methods on the first
frame - and the first frame is always independent.
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4379
Change-Id: I82048a08e2003aac216f483c7db8df997b687149
Reviewed-on: https://skia-review.googlesource.com/4379
Commit-Queue: Matt Sarett <msarett@google.com>
Reviewed-by: Leon Scroggins <scroggo@google.com>
Add a new accessor to retrieve the repetition count.
Remove constants (and corresponding copyright) in SkCodecAnimation.
These may make sense for the calling code, but are not needed here.
kRepetitionCountInfinite corresponds to Blink's kAnimationLoopInfinite.
Move cLoopCountNotSeen to private. It is used to determine whether we
still need to parse. Add a new enum to the parse query - only parse
enough to determine the repetition count.
Unlike Chromium, SkGifCodec does not account for deleting the reader
(which SkGifCodec does not do) or failed decodes.
Add a test.
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2447863002
Review-Url: https://codereview.chromium.org/2447863002
565 cannot take the !writeTransparentPixels path, so disable it for
cases where we might have to take that path.
This only affects frames beyond the first. If the first frame has
a transparent pixel, it will be marked as non-opaque, so we cannot
decode to 565 anyway.
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2441833002
Review-Url: https://codereview.chromium.org/2441833002
