Bug 230270

Summary: Improper masking during animation on method.ac
Product: WebKit Reporter: Jon Lee <jonlee>
Component: AnimationsAssignee: Nobody <webkit-unassigned>
Status: NEW ---    
Severity: Normal CC: dino, graouts, graouts, simon.fraser, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
Description Flags
Reduction none

Description Jon Lee 2021-09-14 11:37:50 PDT
Load https://method.ac/
In the upper right corner is a switch to toggle light and dark mode.

Click on it.

While animating to light mode the bands that make up the background don't get masked by the shape of the switch.
Comment 1 Antoine Quint 2021-09-17 07:04:30 PDT
Not a recent regression, this was already broken in Safari 14.1.2.
Comment 2 Antoine Quint 2021-09-17 07:17:11 PDT
This uses border-radius to achieve the clipping of the toggle, not a mask or a clip.
Comment 3 Antoine Quint 2021-09-17 07:20:43 PDT
Created attachment 438472 [details]

First stab at reducing this and slowing things down to see what's going on. Will reduce further later.
Comment 4 Simon Fraser (smfr) 2021-09-17 08:09:58 PDT
I think this is about changing the compositing layer tree and failing to reconfigure the clip path/mask.
Comment 5 Radar WebKit Bug Importer 2021-09-21 11:38:22 PDT