[webkit-changes] [245393] trunk/Source/WebCore

Thu, 16 May 2019 02:32:55 -0700

Title: [245393] trunk/Source/WebCore
Revision
245393
Author
[email protected]
Date
2019-05-16 02:31:16 -0700 (Thu, 16 May 2019)

Log Message

[FreeType] Some character sequences with a variation selector are not rendered
https://bugs.webkit.org/show_bug.cgi?id=197838

Reviewed by Michael Catanzaro.

We get the invalid glyph instead. See http://mts.io/2015/04/21/unicode-symbol-render-text-emoji/. In the table at
the end the Emoji and Text columns are not correctly rendered. It happens also when copying an emoji from
GtkEmojiChooser and pasting in WebKit text field, because GTK appends U+FE0F to all emojis to force the emoji
style. We need to take into account the variation selector when checking if a font can render a combining
sequence, using FT_Face_GetCharVariantIndex to get the right glyph in case of variation character present.

* platform/graphics/Font.cpp:
(WebCore::Font::platformSupportsCodePoint const): Add optional variation parameter.
(WebCore::Font::canRenderCombiningCharacterSequence const): Take into account variation selector characters
* platform/graphics/Font.h:
* platform/graphics/cairo/FontCairoHarfbuzzNG.cpp:
(WebCore::FontCascade::fontForCombiningCharacterSequence const): Check variation selectors 0xFE0E and 0xFE0F to
decide whether to use the emoji or text style.
* platform/graphics/cocoa/FontCocoa.mm:
(WebCore::Font::platformSupportsCodePoint const): Return false when a variation character is passed so that
characters are checked individually.
* platform/graphics/freetype/SimpleFontDataFreeType.cpp:
(WebCore::Font::platformSupportsCodePoint const): Use FT_Face_GetCharVariantIndex when a variation character is
passed.
* platform/graphics/harfbuzz/ComplexTextControllerHarfBuzz.cpp:
(WebCore::harfBuzzFontFunctions): Do not return true when FT_Face_GetCharVariantIndex returns 0.

Modified Paths

Diff

Modified: trunk/Source/WebCore/ChangeLog (245392 => 245393)


--- trunk/Source/WebCore/ChangeLog	2019-05-16 09:22:22 UTC (rev 245392)
+++ trunk/Source/WebCore/ChangeLog	2019-05-16 09:31:16 UTC (rev 245393)
@@ -1,3 +1,32 @@
+2019-05-16  Carlos Garcia Campos  <[email protected]>
+
+        [FreeType] Some character sequences with a variation selector are not rendered
+        https://bugs.webkit.org/show_bug.cgi?id=197838
+
+        Reviewed by Michael Catanzaro.
+
+        We get the invalid glyph instead. See http://mts.io/2015/04/21/unicode-symbol-render-text-emoji/. In the table at
+        the end the Emoji and Text columns are not correctly rendered. It happens also when copying an emoji from
+        GtkEmojiChooser and pasting in WebKit text field, because GTK appends U+FE0F to all emojis to force the emoji
+        style. We need to take into account the variation selector when checking if a font can render a combining
+        sequence, using FT_Face_GetCharVariantIndex to get the right glyph in case of variation character present.
+
+        * platform/graphics/Font.cpp:
+        (WebCore::Font::platformSupportsCodePoint const): Add optional variation parameter.
+        (WebCore::Font::canRenderCombiningCharacterSequence const): Take into account variation selector characters
+        * platform/graphics/Font.h:
+        * platform/graphics/cairo/FontCairoHarfbuzzNG.cpp:
+        (WebCore::FontCascade::fontForCombiningCharacterSequence const): Check variation selectors 0xFE0E and 0xFE0F to
+        decide whether to use the emoji or text style.
+        * platform/graphics/cocoa/FontCocoa.mm:
+        (WebCore::Font::platformSupportsCodePoint const): Return false when a variation character is passed so that
+        characters are checked individually.
+        * platform/graphics/freetype/SimpleFontDataFreeType.cpp:
+        (WebCore::Font::platformSupportsCodePoint const): Use FT_Face_GetCharVariantIndex when a variation character is
+        passed.
+        * platform/graphics/harfbuzz/ComplexTextControllerHarfBuzz.cpp:
+        (WebCore::harfBuzzFontFunctions): Do not return true when FT_Face_GetCharVariantIndex returns 0.
+
 2019-05-16  Greg Hughes  <[email protected]>
 
         Updated screenHasInvertedColors to use AppKit when available

Modified: trunk/Source/WebCore/platform/graphics/Font.cpp (245392 => 245393)


--- trunk/Source/WebCore/platform/graphics/Font.cpp	2019-05-16 09:22:22 UTC (rev 245392)
+++ trunk/Source/WebCore/platform/graphics/Font.cpp	2019-05-16 09:31:16 UTC (rev 245393)
@@ -33,6 +33,7 @@
 #if PLATFORM(COCOA)
 #include <pal/spi/cocoa/CoreTextSPI.h>
 #endif
+#include "CharacterProperties.h"
 #include "FontCache.h"
 #include "FontCascade.h"
 #include "OpenTypeMathData.h"
@@ -641,9 +642,9 @@
     }
 }
 
-bool Font::platformSupportsCodePoint(UChar32 character) const
+bool Font::platformSupportsCodePoint(UChar32 character, Optional<UChar32> variation) const
 {
-    return glyphForCharacter(character);
+    return variation ? false : glyphForCharacter(character);
 }
 #endif
 
@@ -671,7 +672,23 @@
 {
     ASSERT(isMainThread());
 
-    for (UChar32 codePoint : StringView(characters, length).codePoints()) {
+    auto codePoints = StringView(characters, length).codePoints();
+    auto it = codePoints.begin();
+    auto end = codePoints.end();
+    while (it != end) {
+        auto codePoint = *it;
+        ++it;
+
+        if (it != end && isVariationSelector(*it)) {
+            if (!platformSupportsCodePoint(codePoint, *it)) {
+                // Try the characters individually.
+                if (!supportsCodePoint(codePoint) || !supportsCodePoint(*it))
+                    return false;
+            }
+            ++it;
+            continue;
+        }
+
         if (!supportsCodePoint(codePoint))
             return false;
     }

Modified: trunk/Source/WebCore/platform/graphics/Font.h (245392 => 245393)


--- trunk/Source/WebCore/platform/graphics/Font.h	2019-05-16 09:22:22 UTC (rev 245392)
+++ trunk/Source/WebCore/platform/graphics/Font.h	2019-05-16 09:31:16 UTC (rev 245393)
@@ -175,7 +175,7 @@
     GlyphData glyphDataForCharacter(UChar32) const;
     Glyph glyphForCharacter(UChar32) const;
     bool supportsCodePoint(UChar32) const;
-    bool platformSupportsCodePoint(UChar32) const;
+    bool platformSupportsCodePoint(UChar32, Optional<UChar32> variation = WTF::nullopt) const;
 
     RefPtr<Font> systemFallbackFontForCharacter(UChar32, const FontDescription&, IsForPlatformFont) const;

Modified: trunk/Source/WebCore/platform/graphics/cairo/FontCairoHarfbuzzNG.cpp (245392 => 245393)


--- trunk/Source/WebCore/platform/graphics/cairo/FontCairoHarfbuzzNG.cpp	2019-05-16 09:22:22 UTC (rev 245392)
+++ trunk/Source/WebCore/platform/graphics/cairo/FontCairoHarfbuzzNG.cpp	2019-05-16 09:31:16 UTC (rev 245393)
@@ -115,11 +115,18 @@
         return nullptr;
 
     bool isEmoji = characterSequenceIsEmoji(iterator, character, clusterLength);
+    bool preferColoredFont = isEmoji;
+    // U+FE0E forces text style.
+    // U+FE0F forces emoji style.
+    if (characters[length - 1] == 0xFE0E)
+        preferColoredFont = false;
+    else if (characters[length - 1] == 0xFE0F)
+        preferColoredFont = true;
 
     const Font* baseFont = glyphDataForCharacter(character, false, NormalVariant).font;
     if (baseFont
         && (clusterLength == length || baseFont->canRenderCombiningCharacterSequence(characters, length))
-        && (!isEmoji || baseFont->platformData().isColorBitmapFont()))
+        && (!preferColoredFont || baseFont->platformData().isColorBitmapFont()))
         return baseFont;
 
     for (unsigned i = 0; !fallbackRangesAt(i).isNull(); ++i) {
@@ -127,13 +134,17 @@
         if (!fallbackFont || fallbackFont == baseFont)
             continue;
 
-        if (fallbackFont->canRenderCombiningCharacterSequence(characters, length) && (!isEmoji || fallbackFont->platformData().isColorBitmapFont()))
+        if (fallbackFont->canRenderCombiningCharacterSequence(characters, length) && (!preferColoredFont || fallbackFont->platformData().isColorBitmapFont()))
             return fallbackFont;
     }
 
-    if (auto systemFallback = FontCache::singleton().systemFallbackForCharacters(m_fontDescription, baseFont, IsForPlatformFont::No, isEmoji ? FontCache::PreferColoredFont::Yes : FontCache::PreferColoredFont::No, characters, length)) {
-        if (systemFallback->canRenderCombiningCharacterSequence(characters, length) && (!isEmoji || systemFallback->platformData().isColorBitmapFont()))
+    if (auto systemFallback = FontCache::singleton().systemFallbackForCharacters(m_fontDescription, baseFont, IsForPlatformFont::No, preferColoredFont ? FontCache::PreferColoredFont::Yes : FontCache::PreferColoredFont::No, characters, length)) {
+        if (systemFallback->canRenderCombiningCharacterSequence(characters, length) && (!preferColoredFont || systemFallback->platformData().isColorBitmapFont()))
             return systemFallback.get();
+
+        // In case of emoji, if fallback font is colored try again without the variation selector character.
+        if (isEmoji && characters[length - 1] == 0xFE0F && systemFallback->platformData().isColorBitmapFont() && systemFallback->canRenderCombiningCharacterSequence(characters, length - 1))
+            return systemFallback.get();
     }
 
     return baseFont;

Modified: trunk/Source/WebCore/platform/graphics/cocoa/FontCocoa.mm (245392 => 245393)


--- trunk/Source/WebCore/platform/graphics/cocoa/FontCocoa.mm	2019-05-16 09:22:22 UTC (rev 245392)
+++ trunk/Source/WebCore/platform/graphics/cocoa/FontCocoa.mm	2019-05-16 09:31:16 UTC (rev 245393)
@@ -613,8 +613,11 @@
     return adoptCF(CGPathCreateMutableCopy(result.get()));
 }
 
-bool Font::platformSupportsCodePoint(UChar32 character) const
+bool Font::platformSupportsCodePoint(UChar32 character, Optional<UChar32> variation) const
 {
+    if (variation)
+        return false;
+
     UniChar codeUnits[2];
     CGGlyph glyphs[2];
     CFIndex count = 0;

Modified: trunk/Source/WebCore/platform/graphics/freetype/SimpleFontDataFreeType.cpp (245392 => 245393)


--- trunk/Source/WebCore/platform/graphics/freetype/SimpleFontDataFreeType.cpp	2019-05-16 09:22:22 UTC (rev 245392)
+++ trunk/Source/WebCore/platform/graphics/freetype/SimpleFontDataFreeType.cpp	2019-05-16 09:31:16 UTC (rev 245393)
@@ -201,11 +201,11 @@
     }
 }
 
-bool Font::platformSupportsCodePoint(UChar32 character) const
+bool Font::platformSupportsCodePoint(UChar32 character, Optional<UChar32> variation) const
 {
     CairoFtFaceLocker cairoFtFaceLocker(m_platformData.scaledFont());
     if (FT_Face face = cairoFtFaceLocker.ftFace())
-        return !!FcFreeTypeCharIndex(face, character);
+        return variation ? !!FT_Face_GetCharVariantIndex(face, character, variation.value()) : !!FcFreeTypeCharIndex(face, character);
 
     return false;
 }

Modified: trunk/Source/WebCore/platform/graphics/harfbuzz/ComplexTextControllerHarfBuzz.cpp (245392 => 245393)


--- trunk/Source/WebCore/platform/graphics/harfbuzz/ComplexTextControllerHarfBuzz.cpp	2019-05-16 09:22:22 UTC (rev 245392)
+++ trunk/Source/WebCore/platform/graphics/harfbuzz/ComplexTextControllerHarfBuzz.cpp	2019-05-16 09:31:16 UTC (rev 245393)
@@ -78,7 +78,7 @@
             CairoFtFaceLocker cairoFtFaceLocker(scaledFont);
             if (FT_Face ftFace = cairoFtFaceLocker.ftFace()) {
                 *glyph = FT_Face_GetCharVariantIndex(ftFace, unicode, variation);
-                return true;
+                return !!*glyph;
             }
             return false;
             }, nullptr, nullptr);

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