RESOLVED DUPLICATE of bug 5805257956
REGRESSION (WebKit2): CSS animations on pages that use accelerated compositing pause briefly when clicking on title bar 
https://bugs.webkit.org/show_bug.cgi?id=57956
Summary REGRESSION (WebKit2): CSS animations on pages that use accelerated compositin...
Adam Roben (:aroben)
Reported 2011-04-06 09:15:06 PDT
To reproduce: 1. Go to http://neography.com/experiment/circles/solarsystem/ 2. Click and hold on the window's title bar The CSS animations pause for half a second, then continue. This does not happen in WebKit1.
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Add attachment proposed patch, testcase, etc.
Adam Roben (:aroben)
Comment 1 2011-04-06 09:15:36 PDT
<rdar://problem/9242727>
Adam Roben (:aroben)
Comment 2 2011-04-07 08:43:00 PDT
It looks like the entire main thread pauses when clicking and holding on the title bar. For example, DHTML animations stop, Safari's tabs' spinning progress indicators stop, etc. The only reason CSS animations don't pause in WebKit1 is that the animations are proceeding off the main thread. So really this bug boils down to "CSS animations happen on the main thread in WebKit2".
Adam Roben (:aroben)
Comment 3 2011-04-07 08:51:36 PDT
If you right-click instead of left-click, the animations will pause as long as you hold down the mouse button. See <http://us.generation-nt.com/answer/how-prevent-caption-bar-blocking-message-loop-help-13221142.html>.
Chris Marrin
Comment 4 2011-04-07 09:43:46 PDT
(In reply to comment #2) > It looks like the entire main thread pauses when clicking and holding on the title bar. For example, DHTML animations stop, Safari's tabs' spinning progress indicators stop, etc. The only reason CSS animations don't pause in WebKit1 is that the animations are proceeding off the main thread. > > So really this bug boils down to "CSS animations happen on the main thread in WebKit2". So then is this Not To Be Fixed, or duped?
Adam Roben (:aroben)
Comment 5 2011-04-07 09:46:56 PDT
I do think we want to fix it. We'll just have to fix it by moving CSS animations off the main thread. Note that this could be done even while we're still reading bits back off the GPU into system memory. It's just a simple matter of writing code. :-) I don't think we have a general "CSS animations should happen on a background thread in WebKit2" bug. Maybe this bug could serve as it, or maybe filing a new one (and duping this one to that) would be clearer.
Adam Roben (:aroben)
Comment 6 2011-04-07 09:54:22 PDT
*** This bug has been marked as a duplicate of bug 58052 ***
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