Perform SVG text chunk processing on-the-fly

Source/core/layout/svg/SVGTextChunkBuilder.h

 /*
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  *
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  * along with this library; see the file COPYING.LIB.  If not, write to
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 #ifndef SVGTextChunkBuilder_h
 #define SVGTextChunkBuilder_h
 
-#include "core/layout/svg/SVGTextChunk.h"
 #include "platform/transforms/AffineTransform.h"
 #include "wtf/HashMap.h"
 #include "wtf/Vector.h"
 
 namespace blink {
 
 class SVGInlineTextBox;
 struct SVGTextFragment;
 
 // SVGTextChunkBuilder performs the third layout phase for SVG text.
 //
 // Phase one built the layout information from the SVG DOM stored in the LayoutSVGInlineText objects (SVGTextLayoutAttributes).
 // Phase two performed the actual per-character layout, computing the final positions for each character, stored in the SVGInlineTextBox objects (SVGTextFragment).
 // Phase three performs all modifications that have to be applied to each individual text chunk (text-anchor & textLength).
 
 class SVGTextChunkBuilder {
     WTF_MAKE_NONCOPYABLE(SVGTextChunkBuilder);
 public:
     SVGTextChunkBuilder();
 
-    const Vector<SVGTextChunk>& textChunks() const { return m_textChunks; }
     void processTextChunks(const Vector<SVGInlineTextBox*>&);
     void finalizeTransformMatrices(const Vector<SVGInlineTextBox*>&) const;
 
-    void buildTextChunks(Vector<SVGInlineTextBox*>& lineLayoutBoxes);
-    void layoutTextChunks(Vector<SVGInlineTextBox*>& lineLayoutBoxes);
+protected:
+    virtual void handleTextChunk(const Vector<SVGInlineTextBox*>&, unsigned boxStart, unsigned boxEnd);

[f(malita), 2015/05/27 15:19:13]

The first thing both impls do is create a chunk based on these explicit args.
Would it make more sense to pass a chunk instead?

  handleTextChunk(const SVGTextChunk&)

then maybe clients could construct those on the fly:

  handleTextChunk(SVGTextChunk(lineLayoutBoxes, lastChunkStartPosition,
boxPosition));
     

[fs, 2015/05/27 15:28:07]

I should probably have mentioned this somewhere, but I plan to get rid of
SVGTextChunk [1], and then doing this way means slightly less back-and-forth...
(Next up is killing SVGTextChunk::m_boxes, which means we get
createTextChunk(boxes[boxStart]) instead in the handleTextChunk impls.)

[1] After all, it's just a slice of the full Vector<...> and some properties
that could as well be collected/checked/read when needed instead.

 
 private:
-    void addTextChunk(Vector<SVGInlineTextBox*>& lineLayoutBoxes, unsigned boxPosition, unsigned boxCount);
-    void processTextChunk(const SVGTextChunk&);
-
     void processTextLengthSpacingCorrection(bool isVerticalText, float textLengthShift, Vector<SVGTextFragment>&, unsigned& atCharacter);
     void processTextAnchorCorrection(bool isVerticalText, float textAnchorShift, Vector<SVGTextFragment>&);
 
+    HashMap<SVGInlineTextBox*, AffineTransform> m_textBoxTransformations;
+};
+
+class SVGTextPathChunkBuilder final : public SVGTextChunkBuilder {
+    WTF_MAKE_NONCOPYABLE(SVGTextPathChunkBuilder);
+public:
+    SVGTextPathChunkBuilder();
+
+    float totalLength() const { return m_totalLength; }
+    unsigned totalCharacters() const { return m_totalCharacters; }
+    float totalTextAnchorShift() const { return m_totalTextAnchorShift; }
+
 private:
-    Vector<SVGTextChunk> m_textChunks;
-    HashMap<SVGInlineTextBox*, AffineTransform> m_textBoxTransformations;
+    void handleTextChunk(const Vector<SVGInlineTextBox*>&, unsigned boxStart, unsigned boxEnd) override;
+
+    float m_totalLength;
+    unsigned m_totalCharacters;
+    float m_totalTextAnchorShift;
 };
 
 } // namespace blink
 
 #endif