Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: 720fc1082286802ee65af48d21b4a5dbac84ef5b
https://github.com/WebKit/WebKit/commit/720fc1082286802ee65af48d21b4a5dbac84ef5b
Author: Ahmad Saleem <[email protected]>
Date: 2026-06-12 (Fri, 12 Jun 2026)
Changed paths:
A
LayoutTests/imported/w3c/web-platform-tests/css/css-fonts/synthetic-bold-zero-advance-glyph-expected.txt
A
LayoutTests/imported/w3c/web-platform-tests/css/css-fonts/synthetic-bold-zero-advance-glyph.html
M Source/WebCore/platform/graphics/ComplexTextController.cpp
M Source/WebCore/platform/graphics/WidthIterator.cpp
Log Message:
-----------
Synthetic bold adds advance width to zero-advance glyphs
https://bugs.webkit.org/show_bug.cgi?id=316951
rdar://179418570
Reviewed by Darin Adler and Brent Fulgham.
This patch aligns WebKit with Gecko / Firefox and Blink / Chromium.
Synthetic bold padded every glyph's advance by syntheticBoldOffset()
(fontSize / 36), including glyphs whose real advance is 0 (combining
marks, zero-width spaces, empty/zero-width fonts). A run of such glyphs
measured N * fontSize / 36 wide instead of 0, e.g. a bold heading in a
zero-advance font reserved a visible gap not present in other engines.
A zero-advance glyph draws in place and must not advance the pen.
Letter-spacing already guards this with `if (advance.width())`; apply the
same guard to synthetic bold in both text paths. The simplified-measuring
path asserts no synthetic bold, so it needs no change.
Test: css/css-fonts/synthetic-bold-zero-advance-glyph.html
*
LayoutTests/imported/w3c/web-platform-tests/css/css-fonts/synthetic-bold-zero-advance-glyph-expected.txt:
Added.
*
LayoutTests/imported/w3c/web-platform-tests/css/css-fonts/synthetic-bold-zero-advance-glyph.html:
Added.
(WebCore::ComplexTextController::enclosingGlyphBoundsForTextRun):
* Source/WebCore/platform/graphics/WidthIterator.cpp:
(WebCore::WidthIterator::applyCSSVisibilityRules):
Canonical link: https://commits.webkit.org/315157@main
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