218016 2020-10-21 05:45:03 -0700 Accelerated animations should use the same start time as software animations 2020-10-21 05:50:44 -0700 1 1 1 Unclassified WebKit Animations WebKit Nightly Build Unspecified Unspecified NEW https://bugs.webkit.org/show_bug.cgi?id=217851 InRadar P2 Normal --- 1 graouts webkit-unassigned dino simon.fraser webkit-bug-importer oldest_to_newest 1700149 0 graouts 2020-10-21 05:45:03 -0700 Right now accelerated animations share a start time for a given transaction, and software animations share a start time for a given rendering update, but there's no guarantee that those shared start times are the same for accelerated and software animations started as a result of the same rendering update. 1700151 1 webkit-bug-importer 2020-10-21 05:45:28 -0700 <rdar://problem/70526060> 1700153 2 graouts 2020-10-21 05:48:00 -0700 One way to fix this would be to use the time used by accelerated animations as obtained through GraphicsLayerCA::platformCALayerAnimationStarted() and feed that back to the software animations. 1700155 3 graouts 2020-10-21 05:50:44 -0700 We should also consider not using the animation begin time to bake the time offset in, and instead use nested animations with groups to use the timeOffset property of the CA animation. This way we won't need to hard set a beginTime for animations with an offset in GraphicsLayerCA::updateAnimations().