Track the region where text is painted.

Source/core/platform/graphics/Font.h

Index: Source/core/platform/graphics/Font.h
diff --git a/Source/core/platform/graphics/Font.h b/Source/core/platform/graphics/Font.h
index f41d0a5edd260f4cb22190ce69e36ca48aaa675a..2382014c73309391c8304ee9bb03c94b98317cc9 100644
--- a/Source/core/platform/graphics/Font.h
+++ b/Source/core/platform/graphics/Font.h
@@ -97,8 +97,8 @@ public:
     void update(PassRefPtr<FontSelector>) const;
 
     enum CustomFontNotReadyAction { DoNotPaintIfFontNotReady, UseFallbackIfFontNotReady };
-    void drawText(GraphicsContext*, const TextRun&, const FloatPoint&, int from = 0, int to = -1, CustomFontNotReadyAction = DoNotPaintIfFontNotReady) const;
-    void drawEmphasisMarks(GraphicsContext*, const TextRun&, const AtomicString& mark, const FloatPoint&, int from = 0, int to = -1) const;
+    void drawText(GraphicsContext*, const TextRun&, const FloatPoint&, const FloatRect& textRect, int from = 0, int to = -1, CustomFontNotReadyAction = DoNotPaintIfFontNotReady) const;
+    void drawEmphasisMarks(GraphicsContext*, const TextRun&, const AtomicString& mark, const FloatPoint&, const FloatRect& textRect, int from = 0, int to = -1) const;
 
     float width(const TextRun&, HashSet<const SimpleFontData*>* fallbackFonts = 0, GlyphOverflow* = 0) const;
     float width(const TextRun&, int& charsConsumed, String& glyphName) const;
@@ -173,11 +173,11 @@ private:
 
     // Returns the initial in-stream advance.
     float getGlyphsAndAdvancesForSimpleText(const TextRun&, int from, int to, GlyphBuffer&, ForTextEmphasisOrNot = NotForTextEmphasis) const;
-    void drawSimpleText(GraphicsContext*, const TextRun&, const FloatPoint&, int from, int to) const;
-    void drawEmphasisMarksForSimpleText(GraphicsContext*, const TextRun&, const AtomicString& mark, const FloatPoint&, int from, int to) const;
-    void drawGlyphs(GraphicsContext*, const SimpleFontData*, const GlyphBuffer&, int from, int to, const FloatPoint&) const;
-    void drawGlyphBuffer(GraphicsContext*, const TextRun&, const GlyphBuffer&, const FloatPoint&) const;
-    void drawEmphasisMarks(GraphicsContext*, const TextRun&, const GlyphBuffer&, const AtomicString&, const FloatPoint&) const;
+    void drawSimpleText(GraphicsContext*, const TextRun&, const FloatPoint&, const FloatRect& textRect, int from, int to) const;
+    void drawEmphasisMarksForSimpleText(GraphicsContext*, const TextRun&, const AtomicString& mark, const FloatPoint&, const FloatRect& textRect, int from, int to) const;
+    void drawGlyphs(GraphicsContext*, const SimpleFontData*, const GlyphBuffer&, int from, int to, const FloatPoint&, const FloatRect& textRect) const;
+    void drawGlyphBuffer(GraphicsContext*, const TextRun&, const GlyphBuffer&, const FloatPoint&, const FloatRect& textRect) const;
+    void drawEmphasisMarks(GraphicsContext*, const TextRun&, const GlyphBuffer&, const AtomicString&, const FloatPoint&, const FloatRect& textRect) const;

[eseidel, 2013/04/18 21:04:38]

The rest of these arguments would benifit from clearer names.  Not that you need
to do that in this patch, just noting.

[alokp, 2013/04/18 22:22:37]

Will do in a separate patch.

     float floatWidthForSimpleText(const TextRun&, HashSet<const SimpleFontData*>* fallbackFonts = 0, GlyphOverflow* = 0) const;
     int offsetForPositionForSimpleText(const TextRun&, float position, bool includePartialGlyphs) const;
     FloatRect selectionRectForSimpleText(const TextRun&, const FloatPoint&, int h, int from, int to) const;
@@ -189,8 +189,8 @@ private:
 
     // Returns the initial in-stream advance.
     float getGlyphsAndAdvancesForComplexText(const TextRun&, int from, int to, GlyphBuffer&, ForTextEmphasisOrNot = NotForTextEmphasis) const;
-    void drawComplexText(GraphicsContext*, const TextRun&, const FloatPoint&, int from, int to) const;
-    void drawEmphasisMarksForComplexText(GraphicsContext*, const TextRun&, const AtomicString& mark, const FloatPoint&, int from, int to) const;
+    void drawComplexText(GraphicsContext*, const TextRun&, const FloatPoint&, const FloatRect& textRect, int from, int to) const;
+    void drawEmphasisMarksForComplexText(GraphicsContext*, const TextRun&, const AtomicString& mark, const FloatPoint&, const FloatRect& textRect, int from, int to) const;
     float floatWidthForComplexText(const TextRun&, HashSet<const SimpleFontData*>* fallbackFonts = 0, GlyphOverflow* = 0) const;
     int offsetForPositionForComplexText(const TextRun&, float position, bool includePartialGlyphs) const;
     FloatRect selectionRectForComplexText(const TextRun&, const FloatPoint&, int h, int from, int to) const;