Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: 9df8edf812b7c4330d6f9c1578ef33e57f37457c
https://github.com/WebKit/WebKit/commit/9df8edf812b7c4330d6f9c1578ef33e57f37457c
Author: Myles C. Maxfield <mmaxfi...@apple.com>
Date: 2023-08-27 (Sun, 27 Aug 2023)
Changed paths:
M Source/WebCore/platform/graphics/Font.cpp
M Source/WebCore/platform/graphics/Font.h
M Source/WebCore/platform/graphics/FontCache.h
M Source/WebCore/platform/graphics/FontCascade.cpp
M Source/WebCore/platform/graphics/FontCascade.h
M Source/WebCore/platform/graphics/FontCascadeFonts.cpp
M Source/WebCore/platform/graphics/SystemFallbackFontCache.cpp
M Source/WebCore/platform/graphics/SystemFallbackFontCache.h
M Source/WebCore/platform/graphics/cairo/FontCairoHarfbuzzNG.cpp
M Source/WebCore/platform/graphics/cocoa/FontCacheCoreText.cpp
M Source/WebCore/platform/graphics/coretext/FontCascadeCoreText.cpp
M Source/WebCore/platform/graphics/freetype/FontCacheFreeType.cpp
M Source/WebCore/platform/graphics/freetype/FontSetCache.cpp
M Source/WebCore/platform/graphics/freetype/FontSetCache.h
M Source/WebCore/platform/graphics/win/FontCacheWin.cpp
Log Message:
-----------
[Fonts] systemFallbackForCharacters() only works on individual characters,
not clusters
https://bugs.webkit.org/show_bug.cgi?id=260758
rdar://114481597
Reviewed by Cameron McCormack.
When you pick a font, you have to pick a font for a whole cluster; different
codepoints
in a cluster can't fall back to different fonts. If you've exhausted the whole
font-family
list and you fall off the end, you need to ask the system for a font that can
render
the cluster. The Core Text platform facilities have support for this: they
accept a
character pointer and a length. However, the only problem is that our own
system fallback
code operated on an individual UChar32, rather than on a whole cluster.
This is a classic case of impedence mismatch: At the beginning of the
procedure, you have
clusters, and at the end of the procedure (when we hit Core Text), we operate
on clusters
too. This patch simply hooks up cluster support (via StringViews) throughout
the interior
of the procedure.
Right now, this patch has no behavior change, because the only codepath that
uses this
functionality is our fast text codepath, which currently only operates on a
single
character at a time (another way to think of this: every cluster has exactly
one code
point inside it). If we want to stop using the complex text codepath, this will
be relaxed
in the future, to allow the fast text codepath to operate on whole clusters.
When that day
comes, we'll need to be able to feed the clusters to
systemFallbackForCharacters(), like
this patch allows for. (So, right now, this patch doesn't add any tests,
because there is
no behavior change.)
* Source/WebCore/platform/graphics/Font.cpp:
(WebCore::Font::systemFallbackFontForCharacter const):
* Source/WebCore/platform/graphics/Font.h:
* Source/WebCore/platform/graphics/FontCache.h:
* Source/WebCore/platform/graphics/FontCascadeFonts.cpp:
(WebCore::FontCascadeFonts::glyphDataForSystemFallback):
* Source/WebCore/platform/graphics/SystemFallbackFontCache.cpp:
(WebCore::SystemFallbackFontCache::systemFallbackFontForCharacter):
* Source/WebCore/platform/graphics/SystemFallbackFontCache.h:
(WebCore::add):
(WebCore::SystemFallbackFontCache::CharacterFallbackMapKeyHashTraits::constructDeletedValue):
(WebCore::SystemFallbackFontCache::CharacterFallbackMapKeyHashTraits::isDeletedValue):
* Source/WebCore/platform/graphics/cocoa/FontCacheCoreText.cpp:
(WebCore::lookupFallbackFont):
(WebCore::FontCache::systemFallbackForCharacters):
(WebCore::createFontForCharacters): Deleted.
* Source/WebCore/platform/graphics/coretext/FontCascadeCoreText.cpp:
Canonical link: https://commits.webkit.org/267335@main
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