[webkit-reviews] review requested: [Bug 19663] Image animation timers do not account for paint lag : [Attachment 21886] patch v4

[bugzilla-daemon at webkit.org]

Peter Kasting <zerodpx at gmail.com> has asked  for review:
Bug 19663: Image animation timers do not account for paint lag
https://bugs.webkit.org/show_bug.cgi?id=19663

Attachment 21886: patch v4
https://bugs.webkit.org/attachment.cgi?id=21886&action=edit

------- Additional Comments from Peter Kasting <zerodpx at gmail.com>
Yep, I noticed the missing ChangeLog about an hour ago, oops.

Here's a new version that fixes the ++nextFrame issue (nice catch!), and resets
the timings if the frame is more than five minutes behind.

There is one other consideration with this patch, which is what images should
do which take longer to initially load than they do to actually loop.  The
current behavior, which matches the old behavior, is that the image only "tries
to keep up" once it's fully loaded; before then, the early return in
startAnimation() makes us ignore the frame load times.

I could change this to make the reference point for animation start be the very
first draw of the image.  The effect would be that pages which want to sync
images and other resources would get "better" behavior, but users would see a
strange effect where the image would load, and then jump partway into its next
animation cycle.  I think this is probably too weird and the current behavior
is better, but comments welcome.