Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: 55b5406cac968f0d51f107807530ee74708f40ea
https://github.com/WebKit/WebKit/commit/55b5406cac968f0d51f107807530ee74708f40ea
Author: Alan Baradlay <[email protected]>
Date: 2026-05-04 (Mon, 04 May 2026)
Changed paths:
M LayoutTests/fast/replaced/table-percent-height.html
A
LayoutTests/imported/w3c/web-platform-tests/css/css-ui/widget-percentage-height-001-expected.html
A
LayoutTests/imported/w3c/web-platform-tests/css/css-ui/widget-percentage-height-001-ref.html
A
LayoutTests/imported/w3c/web-platform-tests/css/css-ui/widget-percentage-height-001.html
M LayoutTests/platform/mac/fast/replaced/table-percent-height-expected.txt
M Source/WebCore/rendering/RenderBlock.cpp
M Source/WebCore/rendering/RenderBlock.h
M Source/WebCore/rendering/RenderBox.cpp
M Source/WebCore/rendering/RenderTheme.h
M Source/WebCore/rendering/ios/RenderThemeIOS.h
M Source/WebCore/rendering/ios/RenderThemeIOS.mm
Log Message:
-----------
Percent height border-box content should get correct height in percent height
cells
https://bugs.webkit.org/show_bug.cgi?id=299410
Reviewed by Antti Koivisto.
When a form control like a checkbox or radio button has height: 100% and its
containing block has auto height, the percentage cannot resolve against
anything.
Per CSS Sizing 3, an unresolvable percentage "behaves as auto." Per CSS UI 4,
widgets (form controls with native appearance) are "laid out like replaced
elements," so auto height means their intrinsic size - not zero.
RenderReplaced already handles this correctly: it never returns nullopt for
percentage heights and falls back to intrinsicLogicalHeight() for auto. But
checkboxes and radios in WebKit are RenderBlock (not RenderReplaced), so they go
through RenderBox::computePercentageLogicalHeight, which returns nullopt when
the
percentage cannot resolve. The caller then falls back to the content height,
which is zero for these empty blocks.
The fix has two parts:
1. Override intrinsicSize() on RenderBlock to return the theme's control size
for
elements with appearance.
2. In the PreferredSize overload of computePercentageLogicalHeight, fall back to
intrinsicLogicalHeight() when the percentage cannot resolve. This gives
RenderBlock-based form controls the same fallback behavior that
RenderReplaced
already has.
Tests:
imported/w3c/web-platform-tests/css/css-ui/widget-percentage-height-001-ref.html
imported/w3c/web-platform-tests/css/css-ui/widget-percentage-height-001.html
* LayoutTests/fast/replaced/table-percent-height.html:
*
LayoutTests/imported/w3c/web-platform-tests/css/css-ui/widget-percentage-height-001-expected.html:
Added.
*
LayoutTests/imported/w3c/web-platform-tests/css/css-ui/widget-percentage-height-001-ref.html:
Added.
*
LayoutTests/imported/w3c/web-platform-tests/css/css-ui/widget-percentage-height-001.html:
Added.
* LayoutTests/platform/mac/fast/replaced/table-percent-height-expected.txt:
* Source/WebCore/rendering/RenderBlock.cpp:
(WebCore::RenderBlock::intrinsicSize const):
* Source/WebCore/rendering/RenderBlock.h:
* Source/WebCore/rendering/RenderBox.cpp:
(WebCore::RenderBox::computePercentageLogicalHeight const):
* Source/WebCore/rendering/RenderTheme.h:
* Source/WebCore/rendering/ios/RenderThemeIOS.h:
* Source/WebCore/rendering/ios/RenderThemeIOS.mm:
(WebCore::RenderThemeIOS::controlSize const):
The iOS theme had no controlSize override for checkbox and radio. controlSize
returns the intrinsic control dimensions, which RenderBlock::intrinsicSize()
uses to provide replaced-element-like sizing for form controls.
controlSize now returns max of font size and 16px for checkbox and radio. The
16px matches the iOS UA stylesheet which sets width/height to 16px for these
controls.
Canonical link: https://commits.webkit.org/312526@main
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