Bug 227478

Summary: [css-scroll-snap] Triggering a layout during scroll causes jittery scrolling on Mac when dragging the scrollbar
Product: WebKit Reporter: Martin Robinson <mrobinson>
Component: ScrollingAssignee: Martin Robinson <mrobinson>
Status: RESOLVED FIXED    
Severity: Normal CC: simon.fraser, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: Safari Technology Preview   
Hardware: Unspecified   
OS: Unspecified   
See Also: https://bugs.webkit.org/show_bug.cgi?id=173887
https://bugs.webkit.org/show_bug.cgi?id=228572
Attachments:
Description Flags
Test case
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Patch
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Patch
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Description Martin Robinson 2021-06-29 01:47:36 PDT 
When a page trigger layout during scroll events and with scroll snap, dragging the scrollbar on a Mac causes a lot of jitter while scrolling. The issue is that during layout the code is trying to snap. Each new movement of the scroll bar unsnaps briefly and then the relayout snaps again.
Comment 1 Martin Robinson 2021-06-29 01:48:16 PDT 
Created attachment 432460 [details]
Test case
Comment 2 Martin Robinson 2021-07-01 04:36:08 PDT 
Created attachment 432678 [details]
Patch
Comment 3 Martin Robinson 2021-07-02 03:25:13 PDT 
Created attachment 432774 [details]
Patch
Comment 4 Martin Robinson 2021-07-05 01:32:15 PDT 
Created attachment 432874 [details]
Patch
Comment 5 EWS 2021-07-05 02:21:12 PDT 
Committed r279564 (239395@main): <https://commits.webkit.org/239395@main>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 432874 [details].
Comment 6 Radar WebKit Bug Importer 2021-07-05 02:22:18 PDT 
<rdar://problem/80168708>