Bug 272339

Summary: css zoom doesn't zoom font-size with -webkit-text-size-adjust: none
Product: WebKit Reporter: Michael Lehenabuer <mikelehen>
Component: Layout and RenderingAssignee: Nobody <webkit-unassigned>
Status: NEW    
Severity: Normal CC: bfulgham, karlcow, mikelehen, simon.fraser, webkit-bug-importer, zalan
Priority: P2 Keywords: InRadar
Version: Safari 17   
Hardware: iPhone / iPad   
OS: iOS 17   
URL: https://mikelehen.github.io/public-web/tmp/safari-zoom.html
See Also: https://bugs.webkit.org/show_bug.cgi?id=272351
Attachments:
Description Flags
HTML test case demonstrating bug
none
Screenshot of issue none

Michael Lehenabuer
Reported 2024-04-08 10:25:03 PDT
Created attachment 470816 [details] HTML test case demonstrating bug See attached test case. Live repro here: https://mikelehen.github.io/public-web/tmp/safari-zoom.html With -webkit-text-size-adjust: none; the CSS zoom setting seems to be disregarded when there's an explicit font-size within the zoomed element. Notes: 1. Works in Chrome and Desktop Safari, but not iOS Safari. 2. The font sizes I'm using should be big enough to avoid minimum font sizes, and the bug repros with zoom <1 or >1.
Attachments
HTML test case demonstrating bug (773 bytes, text/html)
2024-04-08 10:25 PDT, Michael Lehenabuer 		no flags
Details
Screenshot of issue (246.23 KB, image/png)
2024-04-08 10:25 PDT, Michael Lehenabuer 		no flags
Details
View All Add attachment proposed patch, testcase, etc.
Michael Lehenabuer
Comment 1 2024-04-08 10:25:31 PDT
Created attachment 470817 [details] Screenshot of issue
Simon Fraser (smfr)
Comment 2 2024-04-08 15:10:39 PDT
Funny story about `-webkit-text-size-adjust`: it was added independently for macOS and iOS. On macOS it means just this: don't scale the font size with zoom. On iOS it means something different: don't apply font boosting logic. So we're kinda stuck with it.
Radar WebKit Bug Importer
Comment 3 2024-04-15 10:31:30 PDT
<rdar://problem/126492290>
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