Makes sure that debug-only layout test failures are not to the ZERO WIDTH SPACE mapping to SPACE glyph complaints (http://b/1317563), fixes a layout test (fast/text/zero-width-characters.html), and provides an updated patch for WebKit.org bug 20237 (https://bugs.webkit.org/show_bug.cgi?id=20237).

This change brings handling of the ZWS and CJK character widths down to the level of SimpleFontData by creating special (sub-classed) SimpleFontData objects that are used in GlyphData. These instances are created when the glyph cache is being filled (GlyphPage::fill). More better things are possible, but at the moment I thought it might be good to just get the basics right.

Also, a couple of the layout tests are brought back to pre-font-metric-hacks removal versions.


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@1557 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 38 insertions, 5 deletions

diff --git a/webkit/pending/SimpleFontData.h b/webkit/pending/SimpleFontData.h
index c1a84aa..1ebdeaa 100644
--- a/webkit/pending/SimpleFontData.h
+++ b/webkit/pending/SimpleFontData.h
@@ -44,6 +44,8 @@ class FontPlatformData;
 class SharedBuffer;
 class SVGFontData;
 class WidthMap;
+class ZeroWidthFontData;
+class CJKWidthFontData;
 
 enum Pitch { UnknownPitch, FixedPitch, VariablePitch };
 
@@ -52,6 +54,10 @@ public:
     SimpleFontData(const FontPlatformData&, bool customFont = false, bool loading = false, SVGFontData* data = 0);
     virtual ~SimpleFontData();
 
+protected:
+    // sub-class constructor
+    SimpleFontData();
+
 public:
     const FontPlatformData& platformData() const { return m_font; }
     SimpleFontData* smallCapsFontData(const FontDescription& fontDescription) const;
@@ -67,7 +73,7 @@ public:
     float xHeight() const { return m_xHeight; }
     unsigned unitsPerEm() const { return m_unitsPerEm; }
 
-    float widthForGlyph(UChar32, Glyph) const;
+    virtual float widthForGlyph(Glyph) const;
     float platformWidthForGlyph(Glyph) const;
 
     virtual const SimpleFontData* fontDataForCharacter(UChar32) const;
@@ -117,12 +123,14 @@ public:
     wxFont getWxFont() const { return m_font.font(); }
 #endif
 
+    const SimpleFontData* zeroWidthFontData() const;
+    const SimpleFontData* cjkWidthFontData() const;
+
 private:
     void platformInit();
     void platformDestroy();
     
     void commonInit();
-    bool IsCJKCodePoint(UChar32) const;
 
 public:
     int m_ascent;
@@ -155,9 +163,6 @@ public:
 
     mutable SimpleFontData* m_smallCapsFontData;
 
-    // Optimization for CJK glyphs
-    mutable float m_cjkGlyphWidth;
-
 #if PLATFORM(CG)
     float m_syntheticBoldOffset;
 #endif
@@ -176,6 +181,34 @@ public:
     mutable SCRIPT_CACHE m_scriptCache;
     mutable SCRIPT_FONTPROPERTIES* m_scriptFontProperties;
 #endif
+
+private:
+    OwnPtr<ZeroWidthFontData> m_zeroWidthFontData;
+    OwnPtr<CJKWidthFontData> m_cjkWidthFontData;
+};
+
+// SimpleFontData sub-classes:
+
+// Has a single zero-width glyph, used for ZWS and 
+// UCHAR_DEFAULT_IGNORABLE_CODE_POINT characters
+class ZeroWidthFontData : public SimpleFontData {
+public:
+    void init(SimpleFontData*);
+    virtual float widthForGlyph(Glyph) const { return 0.0f; }
+};
+
+// Monospaced, single glyph and width, used for CJK characters
+// The assumption made here can break for some high-quality CJK fonts with
+// proportional CJK glyphs.
+class CJKWidthFontData : public ZeroWidthFontData {
+public:
+    CJKWidthFontData();
+
+    virtual float widthForGlyph(Glyph) const;
+
+private:
+    // Optimization for CJK glyphs
+    mutable float m_cjkGlyphWidth;
 };
 
 } // namespace WebCore