Bug 313905

Summary: Text Size Boosting, text-size-adjust, and CSS Zoom
Product: WebKit Reporter: John.W.Jones89
Component: TextAssignee: Nobody <webkit-unassigned>
Status: NEW    
Severity: Normal CC: fantasai.bugs, vitor.roriz
Priority: P2    
Version: Safari 26   
Hardware: iPhone / iPad   
OS: iOS 26   

John.W.Jones89
Reported 2026-05-02 11:53:39 PDT
I see there are some other issues reported with iOS and iPadOS around CSS Zoom and the automatically applied "text boosting" or counter-scaling, though I'm not sure they hit the mark for my issue with it, apologies if this is a duplicate. I contribute to an app that generates previews of pages that are made of containers of text. The preview area has a zoom slider, which is applied to the whole preview area to grow/shrink the pages. Unfortunately, the auto counter-scaling of font-sizing means that as the pages shrink the text inside them does not (at a certain point), and then overflow the pages. It's a pretty big blocker in terms of adapting the site to mobile. Though I've recently realized this isn't a problem on Android. The web app that I'm talking about: https://homebrewery.naturalcrit.com/share/N3AnOcvN6G8a A blog post I've written with some additional screenshots/context: https://longjohnjones.com/homebrewery/article/ios-css-zoom-and-text-scaling/ A CodePen for testing it out (though this likely just affirms the designed behavior-- and I think this is where my report differs from others (I think?). Where I feel that other reports are about bugs, I think what I'm raising an issue with the idea of mandatory text scaling? I'd love to be told I'm just holding `text-size-adjust` wrong and can easily override the size scaling at small sizes. https://codepen.io/editor/Gazook89/pen/019de916-0d86-73c0-94ab-f0bb0302c1dd Thanks for your time
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