242183 2022-06-30 06:01:45 -0700 Janky motion path animation in STP 148 / MacBook Pro with ProMotion 2026-04-17 07:47:50 -0700 1 1 1 Unclassified WebKit Animations Safari Technology Preview Mac (Apple Silicon) Unspecified RESOLVED CONFIGURATION CHANGED https://codepen.io/team/css-tricks/pen/zEpLpK InRadar P2 Normal --- 203847 1 kiet.ho nmouchtaris dino graouts kiet.ho simon.fraser webkit-bug-importer oldest_to_newest 1879339 0 kiet.ho 2022-06-30 06:01:45 -0700 Bug is reported here https://github.com/WebKit/WebKit/pull/806#issuecomment-1170759817. Animation is very janky on a MacBook Pro with M1 Max and ProMotion. The animation becomes even more janky when ProMotion is turned off and the refresh rate is set to 60hz fixed. Issue doesn't occur on WebKit 614.1.19 on a M1 MacBook Pro (no ProMotion, fixed 60hz refresh rate), so I believe this has something to do with the variable refresh rate. 1879374 1 webkit-bug-importer 2022-06-30 08:46:12 -0700 <rdar://problem/96221664> 1879421 2 simon.fraser 2022-06-30 10:31:43 -0700 Offset path animations aren't yet implemented in the compositor, so run on the main thread and should run at 60Hz (but still look smooth). I ran the test on a ProMotion MacBook Pro and it looked smooth. 1879426 3 kiet.ho 2022-06-30 10:38:24 -0700 I borrowed a MBP with ProMotion too and it looks pretty alright (not 120fps smooth but not as bad as the one in the Github issue) 1879456 4 ap 2022-06-30 11:33:53 -0700 *** Bug 242182 has been marked as a duplicate of this bug. *** 2201503 5 graouts 2026-04-17 07:47:50 -0700 We've added support for CSS Motion Path properties to run accelerated as part of the threaded animations features. You can verify this with the latest Safari Technology Preview which has both relevant flags enabled (Threaded Scroll-driven Animations and Threaded Time-based Animations).