[webkit-changes] [WebKit/WebKit] 8b1d31: Add optimization for monospace font's content meas...

[Yusuke Suzuki]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 8b1d31668fbca9ba382333b287d5ed2c97f3212d
      https://github.com/WebKit/WebKit/commit/8b1d31668fbca9ba382333b287d5ed2c97f3212d
  Author: Yusuke Suzuki <ysuzuki at apple.com>
  Date:   2023-12-04 (Mon, 04 Dec 2023)

  Changed paths:
    M Source/WTF/wtf/unicode/CharacterNames.h
    M Source/WebCore/Headers.cmake
    M Source/WebCore/WebCore.xcodeproj/project.pbxproj
    M Source/WebCore/layout/formattingContexts/inline/text/TextUtil.cpp
    M Source/WebCore/platform/graphics/Font.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/FontCascadeFonts.h
    M Source/WebCore/platform/graphics/WidthIterator.cpp
    M Source/WebCore/platform/graphics/WidthIterator.h
    M Source/WebCore/platform/graphics/coretext/FontCoreText.cpp
    M Tools/TestWebKitAPI/CMakeLists.txt
    M Tools/TestWebKitAPI/TestWebKitAPI.xcodeproj/project.pbxproj
    A Tools/TestWebKitAPI/Tests/WebCore/MonospaceFontTests.cpp

  Log Message:
  -----------
  Add optimization for monospace font's content measuring
https://bugs.webkit.org/show_bug.cgi?id=265787
rdar://119124314

Reviewed by Alan Baradlay.

This patch adds an optimization path for monospace fonts when measuring text width.
One of the problem is that a lot of monospace fonts are lying and we cannot simply believe that
this is actually monospace. Thus, our current approach is,

1. When they are monospace fonts from the system, we know that they are actually monospace (by ensuring
   it in our tests). Thus, we can safely assume that their characters are monospace. Only exception is
   "Courier New", which has many strange characters. For now, we disable this optimization for "Courier New".
2. We list up more format category unicode characters in characterCanUseSimplifiedTextMeasuring to avoid using
   monospace fast path for these characters. They are kind of control characters and we do not expect that they
   will appear in texts which should be rendered in a fast path.

* Source/WTF/wtf/unicode/CharacterNames.h:
* Source/WebCore/WebCore.xcodeproj/project.pbxproj:
* Source/WebCore/layout/formattingContexts/inline/text/TextUtil.cpp:
(WebCore::Layout::fixedPitchWidth):
(WebCore::Layout::TextUtil::width):
* Source/WebCore/platform/graphics/Font.h:
(WebCore::Font::canTakeFixedPitchFastContentMeasuring const):
* Source/WebCore/platform/graphics/FontCascade.cpp:
(WebCore::FontCascade::letterSpacing const): Deleted.
(WebCore::FontCascade::wordSpacing const): Deleted.
* Source/WebCore/platform/graphics/FontCascade.h:
(WebCore::FontCascade::canTakeFixedPitchFastContentMeasuring const):
(WebCore::FontCascade::letterSpacing const):
(WebCore::FontCascade::wordSpacing const):
* Source/WebCore/platform/graphics/FontCascadeFonts.cpp:
(WebCore::FontCascadeFonts::determineCanTakeFixedPitchFastContentMeasuring):
* Source/WebCore/platform/graphics/FontCascadeFonts.h:
(WebCore::FontCascadeFonts::isFixedPitch):
(WebCore::FontCascadeFonts::canTakeFixedPitchFastContentMeasuring):
* Source/WebCore/platform/graphics/WidthIterator.cpp:
(WebCore::WidthIterator::characterCanUseSimplifiedTextMeasuring):
* Source/WebCore/platform/graphics/WidthIterator.h:
* Source/WebCore/platform/graphics/coretext/FontCoreText.cpp:
(WebCore::extractBoolean):
(WebCore::Font::determinePitch):
* Tools/TestWebKitAPI/CMakeLists.txt:
* Tools/TestWebKitAPI/TestWebKitAPI.xcodeproj/project.pbxproj:
* Tools/TestWebKitAPI/Tests/WebCore/MonospaceFontTests.cpp: Added.
(TestWebKitAPI::TEST):

Canonical link: https://commits.webkit.org/271524@main