More or less implement RenderTextHarfBuzz

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 gfx {
+
+namespace internal {
+
+struct 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 whether the given shaped run contains any missing glyphs.
+  bool HasMissingGlyphs() 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;
+
+  int width;
+  int preceding_run_widths;
+  Range range;
+  UBiDiDirection direction;
+  UBiDiLevel level;
+  UScriptCode script;
+
+  scoped_ptr<uint16[]> glyphs;
+  scoped_ptr<SkPoint[]> positions;
+  scoped_ptr<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:
+  DISALLOW_COPY_AND_ASSIGN(TextRunHarfBuzz);
+};
+
+}  // namespace internal
+
+class RenderTextHarfBuzz : public RenderText {
+ public:
+  RenderTextHarfBuzz();
+  virtual ~RenderTextHarfBuzz();
+
+  // Overridden from RenderText.
+  virtual Size GetStringSize() OVERRIDE;
+  virtual SelectionModel FindCursorPosition(const Point& point) OVERRIDE;
+  virtual std::vector<FontSpan> GetFontSpansForTesting() OVERRIDE;
+
+ protected:
+  // Overridden from RenderText.
+  virtual int GetLayoutTextBaseline() OVERRIDE;
+  virtual SelectionModel AdjacentCharSelectionModel(
+      const SelectionModel& selection,
+      VisualCursorDirection direction) OVERRIDE;
+  virtual SelectionModel AdjacentWordSelectionModel(
+      const SelectionModel& selection,
+      VisualCursorDirection direction) OVERRIDE;
+  virtual Range GetGlyphBounds(size_t index) OVERRIDE;
+  virtual std::vector<Rect> GetSubstringBounds(const Range& range) OVERRIDE;
+  virtual size_t TextIndexToLayoutIndex(size_t index) const OVERRIDE;
+  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:
+  // 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(
+      const internal::TextRunHarfBuzz* run);
+  SelectionModel LastSelectionModelInsideRun(
+      const internal::TextRunHarfBuzz* run);
+
+  // Break the text into logical runs and populate the visual <-> logical maps.
+  void ItemizeText();
+
+  // Shape the glyphs needed for the text |run|.
+  void ShapeRun(internal::TextRunHarfBuzz* run);
+
+  // 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_;
+
+  DISALLOW_COPY_AND_ASSIGN(RenderTextHarfBuzz);
+};
+
+}  // namespace gfx
+
+#endif  // UI_GFX_RENDER_TEXT_HARFBUZZ_H_