ui/gfx/render_text_harfbuzz.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef UI_GFX_RENDER_TEXT_HARFBUZZ_H_
   6 #define UI_GFX_RENDER_TEXT_HARFBUZZ_H_
   7
   8 #include "base/memory/scoped_ptr.h"
   9 #include "base/memory/scoped_vector.h"
  10 #include "third_party/harfbuzz-ng/src/hb.h"
  11 #include "third_party/icu/source/common/unicode/ubidi.h"
  12 #include "third_party/icu/source/common/unicode/uscript.h"
  13 #include "ui/gfx/render_text.h"
  14
  15 namespace gfx {
  16
  17 namespace internal {
  18
  19 struct GFX_EXPORT TextRunHarfBuzz {
  20   TextRunHarfBuzz();
  21   ~TextRunHarfBuzz();
  22
  23   // Returns the index of the first glyph that corresponds to the character at
  24   // |pos|.
  25   size_t CharToGlyph(size_t pos) const;
  26
  27   // Returns the corresponding glyph range of the given character range.
  28   // |range| is in text-space (0 corresponds to |GetLayoutText()[0]|). Returned
  29   // value is in run-space (0 corresponds to the first glyph in the run).
  30   Range CharRangeToGlyphRange(const Range& range) const;
  31
  32   // Returns the number of missing glyphs in the shaped text run.
  33   size_t CountMissingGlyphs() const;
  34
  35   // Returns the X coordinate of the leading or |trailing| edge of the glyph
  36   // starting at |text_index|, relative to the left of the text (not the view).
  37   int GetGlyphXBoundary(size_t text_index, bool trailing) const;
  38
  39   int width;
  40   int preceding_run_widths;
  41   Range range;
  42   bool is_rtl;
  43   UBiDiLevel level;
  44   UScriptCode script;
  45
  46   scoped_ptr<uint16[]> glyphs;
  47   scoped_ptr<SkPoint[]> positions;
  48   scoped_ptr<uint32[]> glyph_to_char;
  49   size_t glyph_count;
  50
  51   skia::RefPtr<SkTypeface> skia_face;
  52   int font_size;
  53   int font_style;
  54   bool strike;
  55   bool diagonal_strike;
  56   bool underline;
  57
  58  private:
  59   DISALLOW_COPY_AND_ASSIGN(TextRunHarfBuzz);
  60 };
  61
  62 }  // namespace internal
  63
  64 class GFX_EXPORT RenderTextHarfBuzz : public RenderText {
  65  public:
  66   RenderTextHarfBuzz();
  67   virtual ~RenderTextHarfBuzz();
  68
  69   // Overridden from RenderText.
  70   virtual Size GetStringSize() OVERRIDE;
  71   virtual SelectionModel FindCursorPosition(const Point& point) OVERRIDE;
  72   virtual std::vector<FontSpan> GetFontSpansForTesting() OVERRIDE;
  73
  74  protected:
  75   // Overridden from RenderText.
  76   virtual int GetLayoutTextBaseline() OVERRIDE;
  77   virtual SelectionModel AdjacentCharSelectionModel(
  78       const SelectionModel& selection,
  79       VisualCursorDirection direction) OVERRIDE;
  80   virtual SelectionModel AdjacentWordSelectionModel(
  81       const SelectionModel& selection,
  82       VisualCursorDirection direction) OVERRIDE;
  83   virtual Range GetGlyphBounds(size_t index) OVERRIDE;
  84   virtual std::vector<Rect> GetSubstringBounds(const Range& range) OVERRIDE;
  85   virtual size_t TextIndexToLayoutIndex(size_t index) const OVERRIDE;
  86   virtual size_t LayoutIndexToTextIndex(size_t index) const OVERRIDE;
  87   virtual bool IsValidCursorIndex(size_t index) OVERRIDE;
  88   virtual void ResetLayout() OVERRIDE;
  89   virtual void EnsureLayout() OVERRIDE;
  90   virtual void DrawVisualText(Canvas* canvas) OVERRIDE;
  91
  92  private:
  93   friend class RenderTextTest;
  94   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_RunDirection);
  95   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_BreakRunsByUnicodeBlocks);
  96
  97   // Return the run index that contains the argument; or the length of the
  98   // |runs_| vector if argument exceeds the text length or width.
  99   size_t GetRunContainingCaret(const SelectionModel& caret) const;
 100   size_t GetRunContainingXCoord(int x, int* offset) const;
 101
 102   // Given a |run|, returns the SelectionModel that contains the logical first
 103   // or last caret position inside (not at a boundary of) the run.
 104   // The returned value represents a cursor/caret position without a selection.
 105   SelectionModel FirstSelectionModelInsideRun(
 106       const internal::TextRunHarfBuzz* run);
 107   SelectionModel LastSelectionModelInsideRun(
 108       const internal::TextRunHarfBuzz* run);
 109
 110   // Break the text into logical runs and populate the visual <-> logical maps.
 111   void ItemizeText();
 112
 113   // Shape the glyphs needed for the text |run|.
 114   void ShapeRun(internal::TextRunHarfBuzz* run);
 115   void ShapeRunWithFont(internal::TextRunHarfBuzz* run,
 116                         const std::string& font);
 117
 118   // Text runs in logical order.
 119   ScopedVector<internal::TextRunHarfBuzz> runs_;
 120
 121   // Maps visual run indices to logical run indices and vice versa.
 122   std::vector<int32_t> visual_to_logical_;
 123   std::vector<int32_t> logical_to_visual_;
 124
 125   bool needs_layout_;
 126
 127   DISALLOW_COPY_AND_ASSIGN(RenderTextHarfBuzz);
 128 };
 129
 130 }  // namespace gfx
 131
 132 #endif  // UI_GFX_RENDER_TEXT_HARFBUZZ_H_