Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: d0717a48c4d0070c07336fad891fa31164bf9d54
https://github.com/WebKit/WebKit/commit/d0717a48c4d0070c07336fad891fa31164bf9d54
Author: Alan Baradlay <[email protected]>
Date: 2026-07-23 (Thu, 23 Jul 2026)
Changed paths:
M Source/WebCore/rendering/RenderListMarker.cpp
Log Message:
-----------
[CSS] Inside list marker glyph can be painted a pixel off from equivalent
inline text
https://bugs.webkit.org/show_bug.cgi?id=319623
rdar://182447949
Reviewed by Antti Koivisto.
A list-style-position: inside marker paints its glyph in
RenderListMarker::paint()
using markerRect.y(), which comes from the renderer's location(). Line layout
sets
that location by truncating the marker's float inline-layout position to the
LayoutUnit (1/64px) grid (LayoutIntegration::LineLayout assigns it via
toLayoutPoint()). Inline text, by contrast, paints from the InlineDisplay::Box
at
full float precision. When the sub-1/64px fraction dropped by the truncation is
enough to tip the device-pixel rounding of the baseline, the marker glyph lands
one
device pixel away from the same glyph rendered as inline text.
This was latent until the iOS font-metrics convergence (bug 319190) shifted the
ascent so the text baseline falls exactly on a device-pixel boundary, making the
lost fraction decide the rounding.
Take the marker's block-axis paint position straight from its line box instead
of
the truncated location(), so the glyph baseline keeps the same float precision
as
inline text and device-pixel rounds identically. Limited to horizontal writing
modes; vertical writing modes have a separate marker line-box mispositioning
tracked by bug 319618.
* Source/WebCore/rendering/RenderListMarker.cpp:
(WebCore::RenderListMarker::paint):
Canonical link: https://commits.webkit.org/317789@main
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