Attachment 369368 Details for Bug 197658 – Patch

[patch] Patch

wcore-ft-space-width.diff (text/plain), 3.17 KB, created by Carlos Garcia Campos on 2019-05-08 02:37:31 PDT

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Creator: Carlos Garcia Campos

Created: 2019-05-08 02:37:31 PDT

Size: 3.17 KB

patch

obsolete

>diff --git a/Source/WebCore/ChangeLog b/Source/WebCore/ChangeLog
>index 26177d0480c..592b2ee339f 100644
>--- a/Source/WebCore/ChangeLog
>+++ b/Source/WebCore/ChangeLog
>@@ -1,3 +1,24 @@
>+2019-05-08  Carlos Garcia Campos  <cgarcia@igalia.com>
>+
>+        REGRESSION(r239915): [FreeType] White space skipped when rendering plain text with noto CJK font
>+        https://bugs.webkit.org/show_bug.cgi?id=197658
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        Since r239915 we no longer overwrite control characters with zero width space, they are handled later when
>+        filling the glyph pages. In Font::platformGlyphInit() there's an optimization to get the glyph of zero with
>+        space character that assumes that control characters are always overwritten. Since the glyph for character at 0
>+        index is always overwritten with zero width space, we can avoid loading the page for the actual zero width space
>+        character and use the first page instead. In the particular case of noto CJK font, character at 0 is mapped to
>+        the same glyph as space character, so space and zero width space end up being the same glyph. That breaks the
>+        space width calculation, that returns 0 when isZeroWidthSpaceGlyph() is true. That's why spaces are no
>+        longer rendered, ComplexTextController::adjustGlyphsAndAdvances() is setting the x advance for the space glyphs
>+        to 0.
>+
>+        * platform/graphics/Font.cpp:
>+        (WebCore::Font::platformGlyphInit): Use the actual zero width space page to get the glyph instead of 0 when
>+        using FreeType.
>+
> 2019-05-07  Antti Koivisto  <antti@apple.com>
> 
>         <body> with overflow:hidden CSS is scrollable on iOS
>diff --git a/Source/WebCore/platform/graphics/Font.cpp b/Source/WebCore/platform/graphics/Font.cpp
>index eb5a17bf180..cc94d6cdcff 100644
>--- a/Source/WebCore/platform/graphics/Font.cpp
>+++ b/Source/WebCore/platform/graphics/Font.cpp
>@@ -102,14 +102,20 @@ void Font::initCharWidths()
> 
> void Font::platformGlyphInit()
> {
>-    auto* glyphPageZero = glyphPage(0);
>+#if USE(FREETYPE)
>+    auto* glyphPageZeroWidthSpace = glyphPage(GlyphPage::pageNumberForCodePoint(zeroWidthSpace));
>+    UChar32 zeroWidthSpaceCharacter = zeroWidthSpace;
>+#else
>+    // Ask for the glyph for 0 to avoid paging in ZERO WIDTH SPACE. Control characters, including 0,
>+    // are mapped to the ZERO WIDTH SPACE glyph for non FreeType based ports.
>+    auto* glyphPageZeroWidthSpace = glyphPage(0);
>+    UChar32 zeroWidthSpaceCharacter = 0;
>+#endif
>     auto* glyphPageCharacterZero = glyphPage(GlyphPage::pageNumberForCodePoint('0'));
>     auto* glyphPageSpace = glyphPage(GlyphPage::pageNumberForCodePoint(space));
> 
>-    // Ask for the glyph for 0 to avoid paging in ZERO WIDTH SPACE. Control characters, including 0,
>-    // are mapped to the ZERO WIDTH SPACE glyph.
>-    if (glyphPageZero)
>-        m_zeroWidthSpaceGlyph = glyphPageZero->glyphDataForCharacter(0).glyph;
>+    if (glyphPageZeroWidthSpace)
>+        m_zeroWidthSpaceGlyph = glyphPageZeroWidthSpace->glyphDataForCharacter(zeroWidthSpaceCharacter).glyph;
> 
>     // Nasty hack to determine if we should round or ceil space widths.
>     // If the font is monospace or fake monospace we ceil to ensure that

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mcatanzaro: review+

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Attachments on bug 197658: 369368 | 369373