Bug 300287

Summary: REGRESSION(300183@main): Pixel cracks on borders when zooming out/in with trackpad
Product: WebKit Reporter: Karl Dubost <karlcow>
Component: Layout and RenderingAssignee: Nobody <webkit-unassigned>
Status: NEW    
Severity: Normal CC: bfulgham, sabouhallawa, simon.fraser, webkit-bug-importer, zalan
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
See Also: https://bugs.webkit.org/show_bug.cgi?id=267566
https://bugs.webkit.org/show_bug.cgi?id=301125
Attachments:
Description Flags
testcase
none
screenrecording of the issue none

Karl Dubost
Reported 2025-10-06 20:13:25 PDT
Created attachment 476992 [details] testcase 1. with STP Release 229 (WebKit 21623.1.9.1) on a macbook Pro on Tahoe 2. open the testcase 3. zoom in and out with the trackpad Results: Time to time a white line appears on one of the box borders.
Attachments
testcase (586 bytes, text/html)
2025-10-06 20:13 PDT, Karl Dubost 		no flags
Details
screenrecording of the issue (2.39 MB, video/quicktime)
2025-10-06 20:16 PDT, Karl Dubost 		no flags
Details
View All Add attachment proposed patch, testcase, etc.
Karl Dubost
Comment 1 2025-10-06 20:16:37 PDT
Created attachment 476993 [details] screenrecording of the issue We can see the thin line on all borders at the end of the screen recording.
Karl Dubost
Comment 2 2025-10-06 20:18:42 PDT
This was initially reported by https://mastodon.social/@metaning/115310925432268117
Radar WebKit Bug Importer
Comment 3 2025-10-13 20:14:11 PDT
<rdar://problem/162572663>
Said Abou-Hallawa
Comment 4 2025-10-14 08:39:15 PDT
This is a regression of 300183@main, see bug 267566. If the experimental feature "GraphicsContext Blur Filter Rendering" is turned off, the bug does not happen.
Simon Fraser (smfr)
Comment 5 2025-10-14 09:27:10 PDT
The test doesn't have any filters though, only box-shadow.
Simon Fraser (smfr)
Comment 6 2025-10-20 13:58:58 PDT
I can reproduce pixel cracks after disabling graphics context blur filter.
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