Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: d221d71a6a560cb45bb3e9b23e526b6bcfa9e4b3
https://github.com/WebKit/WebKit/commit/d221d71a6a560cb45bb3e9b23e526b6bcfa9e4b3
Author: Brent Fulgham <[email protected]>
Date: 2026-05-09 (Sat, 09 May 2026)
Changed paths:
A
LayoutTests/fast/text-autosizing/ios/idempotentmode/text-size-adjust-with-css-zoom-expected.txt
A
LayoutTests/fast/text-autosizing/ios/idempotentmode/text-size-adjust-with-css-zoom.html
M Source/WebCore/style/StyleBuilderState.cpp
Log Message:
-----------
CSS Zoom interacts oddly with explicit font-size and font-variant on iPad
https://bugs.webkit.org/show_bug.cgi?id=293617
rdar://152173269
Reviewed by Sammy Gill.
Our efforts to provide a great user experience on iPad with desktop website
content had
an unintended consequence that resulted in strange adjustments to fonts during
zooming.
updateFontForTextSizeAdjust() was setting computedSize directly from
specifiedSize without
accounting for the element's zoom factor. When CSS zoom is inherited (same as
parent),
updateFontForZoomChange() does not fire afterward to re-apply it, leaving the
computed
font size without zoom. This caused incorrect font metrics for elements with
explicit
text-size-adjust inside zoomed containers, breaking font-variant, font-weight,
and
font-style rendering on iPadOS desktop mode.
This change fixes this by computing the zoom factor (usedZoom * textZoomFactor)
directly
in updateFontForTextSizeAdjust(), bypassing minimum font size clamping which
should not
constrain author-specified text-size-adjust values. We also add an early return
in
updateFontForZoomChange() when text-size-adjust has already computed the
correct zoomed
size, so it doesn't overwrite the result when zoom differs from the parent.
Test:
fast/text-autosizing/ios/idempotentmode/text-size-adjust-with-css-zoom.html
*
LayoutTests/fast/text-autosizing/ios/idempotentmode/text-size-adjust-with-css-zoom-expected.txt:
Added.
*
LayoutTests/fast/text-autosizing/ios/idempotentmode/text-size-adjust-with-css-zoom.html:
Added.
* Source/WebCore/style/StyleBuilderState.cpp:
(WebCore::Style::BuilderState::updateFontForTextSizeAdjust):
(WebCore::Style::BuilderState::updateFontForZoomChange):
Canonical link: https://commits.webkit.org/312944@main
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