Bug 290389

Summary: Scrolling text with a scale transform is pixellated
Product: WebKit Reporter: Les Pozdena <les>
Component: Layout and RenderingAssignee: Nobody <webkit-unassigned>
Status: NEW    
Severity: Critical CC: bfulgham, karlcow, simon.fraser, webkit-bug-importer, zalan
Priority: P2 Keywords: BrowserCompat, InRadar
Version: Safari 18   
Hardware: Mac (Apple Silicon)   
OS: macOS 15   
See Also: https://bugs.webkit.org/show_bug.cgi?id=27684
Attachments:
Description Flags
Video of me reproducing the bug and showing how the styles affect it none

Les Pozdena
Reported 2025-03-25 09:03:14 PDT
Created attachment 474705 [details] Video of me reproducing the bug and showing how the styles affect it If you have an element with scrolling text and a style like this: overflow: auto; transform: translateX(20px) scale(3); It will appear pixellated. If you remove the overflow style or you don't scale it, it will appear smoothly rendered. You can see a repro case here: https://3dsx8p.csb.app/ This only affects Safari/WebKit. Firefox and Chrome never have this issue. See attached video as well. This is critical for the web app I'm working on; there is currently no viable workaround for us, so we are recommending, for now, that users do not use our web app with Safari. Once this is fixed, we can recommend it again.
Attachments
Video of me reproducing the bug and showing how the styles affect it (52.43 MB, video/mp4)
2025-03-25 09:03 PDT, Les Pozdena 		no flags
Details
View All Add attachment proposed patch, testcase, etc.
Simon Fraser (smfr)
Comment 1 2025-03-25 18:10:05 PDT
Is your web app a shipping product? Could you say what it is so that we can judge impact? Thanks.
Les Pozdena
Comment 2 2025-03-25 19:27:01 PDT
It's the coming web app version of Notability (our existing iPad app). We haven't shipped quite yet, but I can say here that we're entering public beta soon.
Radar WebKit Bug Importer
Comment 3 2025-04-01 09:06:53 PDT
<rdar://problem/148341827>
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