Track the region where text is painted.

Source/core/platform/graphics/harfbuzz/FontHarfBuzz.cpp

 /*
  * Copyright (c) 2007, 2008, 2010 Google Inc. All rights reserved.
  * 
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  * 
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 43 matching lines @@
     return false;
 }
 
 bool Font::canExpandAroundIdeographsInComplexText()
 {
     return false;
 }
 
 void Font::drawGlyphs(GraphicsContext* gc, const SimpleFontData* font,
                       const GlyphBuffer& glyphBuffer,  int from, int numGlyphs,
-                      const FloatPoint& point) const {
+                      const FloatPoint& point, const FloatRect& textRect) const {
     SkASSERT(sizeof(GlyphBufferGlyph) == sizeof(uint16_t)); // compile-time assert
 
     const GlyphBufferGlyph* glyphs = glyphBuffer.glyphs(from);
     SkScalar x = SkFloatToScalar(point.x());
     SkScalar y = SkFloatToScalar(point.y());
 
     // FIXME: text rendering speed:
     // Android has code in their WebCore fork to special case when the
     // GlyphBuffer has no advances other than the defaults. In that case the
     // text drawing can proceed faster. However, it's unclear when those
@@ skipping 27 matching lines @@
         font->platformData().setupPaint(&paint);
         gc->platformContext()->adjustTextRenderMode(&paint);
         paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
 
         if (isVertical) {
             SkPath path;
             for (int i = 0; i < numGlyphs; ++i) {
                 path.reset();
                 path.moveTo(vPosBegin[i]);
                 path.lineTo(vPosEnd[i]);
-                platformContext->drawTextOnPath(glyphs + i, 2, path, 0, paint);
+                platformContext->drawTextOnPath(glyphs + i, 2, path, textRect, 0, paint);
             }
         } else
-            platformContext->drawPosText(glyphs, numGlyphs << 1, pos, paint);
+            platformContext->drawPosText(glyphs, numGlyphs << 1, pos, textRect, paint);
     }
 
     if ((textMode & TextModeStroke)
         && gc->platformContext()->getStrokeStyle() != NoStroke
         && gc->platformContext()->getStrokeThickness() > 0) {
 
         SkPaint paint;
         gc->platformContext()->setupPaintForStroking(&paint, 0, 0);
         font->platformData().setupPaint(&paint);
         gc->platformContext()->adjustTextRenderMode(&paint);
         paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
 
         if (textMode & TextModeFill) {
             // If we also filled, we don't want to draw shadows twice.
             // See comment in FontChromiumWin.cpp::paintSkiaText() for more details.
             // Since we use the looper for shadows, we remove it (if any) now.
             paint.setLooper(0);
         }
 
         if (isVertical) {
             SkPath path;
             for (int i = 0; i < numGlyphs; ++i) {
                 path.reset();
                 path.moveTo(vPosBegin[i]);
                 path.lineTo(vPosEnd[i]);
-                platformContext->drawTextOnPath(glyphs + i, 2, path, 0, paint);
+                platformContext->drawTextOnPath(glyphs + i, 2, path, textRect, 0, paint);
             }
         } else
-            platformContext->drawPosText(glyphs, numGlyphs << 1, pos, paint);
+            platformContext->drawPosText(glyphs, numGlyphs << 1, pos, textRect, paint);
     }
 }
 
 static void setupForTextPainting(SkPaint* paint, SkColor color)
 {
     paint->setTextEncoding(SkPaint::kGlyphID_TextEncoding);
     paint->setColor(color);
 }
 
 void Font::drawComplexText(GraphicsContext* gc, const TextRun& run,
-                           const FloatPoint& point, int from, int to) const
+                           const FloatPoint& point, const FloatRect& textRect,
+                           int from, int to) const
 {
     if (!run.length())
         return;
 
     TextDrawingModeFlags textMode = gc->platformContext()->getTextDrawingMode();
     bool fill = textMode & TextModeFill;
     bool stroke = (textMode & TextModeStroke)
                && gc->platformContext()->getStrokeStyle() != NoStroke
                && gc->platformContext()->getStrokeThickness() > 0;
 
     if (!fill && !stroke)
         return;
 
     SkPaint strokePaint, fillPaint;
     if (fill) {
         gc->platformContext()->setupPaintForFilling(&fillPaint);
         setupForTextPainting(&fillPaint, gc->fillColor().rgb());
     }
     if (stroke) {
         gc->platformContext()->setupPaintForStroking(&strokePaint, 0, 0);
         setupForTextPainting(&strokePaint, gc->strokeColor().rgb());
     }
 
     GlyphBuffer glyphBuffer;
     HarfBuzzShaper shaper(this, run);
     shaper.setDrawRange(from, to);
     if (!shaper.shape(&glyphBuffer))
         return;
     FloatPoint adjustedPoint = shaper.adjustStartPoint(point);
-    drawGlyphBuffer(gc, run, glyphBuffer, adjustedPoint);
+    drawGlyphBuffer(gc, run, glyphBuffer, adjustedPoint, textRect);
 }
 
-void Font::drawEmphasisMarksForComplexText(GraphicsContext* /* context */, const TextRun& /* run */, const AtomicString& /* mark */, const FloatPoint& /* point */, int /* from */, int /* to */) const
+void Font::drawEmphasisMarksForComplexText(GraphicsContext* /* context */, const TextRun& /* run */, const AtomicString& /* mark */, const FloatPoint& /* point */, const FloatRect& /* textRect */, int /* from */, int /* to */) const
 {
     notImplemented();
 }
 
 float Font::floatWidthForComplexText(const TextRun& run, HashSet<const SimpleFontData*>* /* fallbackFonts */, GlyphOverflow* /* glyphOverflow */) const
 {
     HarfBuzzShaper shaper(this, run);
     if (!shaper.shape())
         return 0;
     return shaper.totalWidth();
@@ skipping 14 matching lines @@
                                             const FloatPoint& point, int height,
                                             int from, int to) const
 {
     HarfBuzzShaper shaper(this, run);
     if (!shaper.shape())
         return FloatRect();
     return shaper.selectionRect(point, height, from, to);
 }
 
 } // namespace WebCore