Bug 258346

Summary: Using keyframe animation with box-shadow causes slowdown due to constant layout calls.
Product: WebKit Reporter: Paul Connolly <paulconnolly>
Component: Layout and RenderingAssignee: Nobody <webkit-unassigned>
Status: NEW ---    
Severity: Normal CC: bfulgham, dino, graouts, simon.fraser, webkit-bug-importer, zalan
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: All   
OS: All   
Attachments:
Description Flags
Test Case showing the animation issue with box-shadow none

Description Paul Connolly 2023-06-21 02:56:20 PDT 
Created attachment 466774 [details]
Test Case showing the animation issue with box-shadow

When using an animation that animates the box-shadow CSS property, performance on Webkit 265348@main, Safari on macOS, iOS etc. is affected due to constant "Styles Invalidated" calls, and Layout / Paint calls.
Test case attached.
Comment 1 Simon Fraser (smfr) 2023-06-21 12:00:37 PDT 
Box shadow affects visual overflow, so we have to do some kind of layout to recompute this.
Comment 2 Radar WebKit Bug Importer 2023-06-21 12:00:58 PDT 
<rdar://problem/111116324>