RenderTextHarfBuzz: Allow mid-glyph cursors in multi-grapheme clusters

ui/gfx/render_text_harfbuzz.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_GFX_RENDER_TEXT_HARFBUZZ_H_
 #define UI_GFX_RENDER_TEXT_HARFBUZZ_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
 #include "third_party/harfbuzz-ng/src/hb.h"
 #include "third_party/icu/source/common/unicode/ubidi.h"
 #include "third_party/icu/source/common/unicode/uscript.h"
 #include "ui/gfx/render_text.h"
 
+namespace base {
+namespace i18n {
+class BreakIterator;
+}
+}
+
 namespace gfx {
 
 namespace internal {
 
 struct GFX_EXPORT TextRunHarfBuzz {
   TextRunHarfBuzz();
   ~TextRunHarfBuzz();
 
   // Returns the index of the first glyph that corresponds to the character at
   // |pos|.
   size_t CharToGlyph(size_t pos) const;
 
   // Returns the corresponding glyph range of the given character range.
   // |range| is in text-space (0 corresponds to |GetLayoutText()[0]|). Returned
   // value is in run-space (0 corresponds to the first glyph in the run).
   Range CharRangeToGlyphRange(const Range& range) const;
 
   // Returns the number of missing glyphs in the shaped text run.
   size_t CountMissingGlyphs() const;
 
-  // Returns the X coordinate of the leading or |trailing| edge of the glyph
-  // starting at |text_index|, relative to the left of the text (not the view).
-  int GetGlyphXBoundary(size_t text_index, bool trailing) const;
+  // Writes the character and glyph ranges of the cluster containing |pos|.
+  void GetClusterAt(size_t pos, Range* chars, Range* glyphs) const;
+
+  // Returns the grapheme bounds at |text_index|. Handles multi-grapheme glyphs.
+  Range GetGraphemeBounds(base::i18n::BreakIterator* grapheme_iterator,
+                          size_t text_index);
+
+  // Returns whether the given shaped run contains any missing glyphs.
+  bool HasMissingGlyphs() const;
 
   int width;
   int preceding_run_widths;
   Range range;
   bool is_rtl;
   UBiDiLevel level;
   UScriptCode script;
 
   scoped_ptr<uint16[]> glyphs;
   scoped_ptr<SkPoint[]> positions;
-  scoped_ptr<uint32[]> glyph_to_char;
+  std::vector<uint32> glyph_to_char;
   size_t glyph_count;
 
   skia::RefPtr<SkTypeface> skia_face;
   int font_size;
   int font_style;
   bool strike;
   bool diagonal_strike;
   bool underline;
 
  private:
@@ skipping 27 matching lines @@
   virtual size_t LayoutIndexToTextIndex(size_t index) const OVERRIDE;
   virtual bool IsValidCursorIndex(size_t index) OVERRIDE;
   virtual void ResetLayout() OVERRIDE;
   virtual void EnsureLayout() OVERRIDE;
   virtual void DrawVisualText(Canvas* canvas) OVERRIDE;
 
  private:
   friend class RenderTextTest;
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_RunDirection);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_BreakRunsByUnicodeBlocks);
+  FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_SubglyphGraphemeCases);
+  FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_SubglyphGraphemePartition);
 
   // Return the run index that contains the argument; or the length of the
   // |runs_| vector if argument exceeds the text length or width.
   size_t GetRunContainingCaret(const SelectionModel& caret) const;
   size_t GetRunContainingXCoord(int x, int* offset) const;
 
   // Given a |run|, returns the SelectionModel that contains the logical first
   // or last caret position inside (not at a boundary of) the run.
   // The returned value represents a cursor/caret position without a selection.
   SelectionModel FirstSelectionModelInsideRun(
@@ skipping 11 matching lines @@
 
   // Text runs in logical order.
   ScopedVector<internal::TextRunHarfBuzz> runs_;
 
   // Maps visual run indices to logical run indices and vice versa.
   std::vector<int32_t> visual_to_logical_;
   std::vector<int32_t> logical_to_visual_;
 
   bool needs_layout_;
 
+  // ICU grapheme iterator for the layout text. Valid when |!needs_layout_|. Can
+  // be NULL in case of an error.
+  scoped_ptr<base::i18n::BreakIterator> grapheme_iterator_;
+
   DISALLOW_COPY_AND_ASSIGN(RenderTextHarfBuzz);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_RENDER_TEXT_HARFBUZZ_H_