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 base {
  16 namespace i18n {
  17 class BreakIterator;
  18 }
  19 }
  20
  21 namespace gfx {
  22
  23 namespace internal {
  24
  25 struct GFX_EXPORT TextRunHarfBuzz {
  26   TextRunHarfBuzz();
  27   ~TextRunHarfBuzz();
  28
  29   // Returns the index of the first glyph that corresponds to the character at
  30   // |pos|.
  31   size_t CharToGlyph(size_t pos) const;
  32
  33   // Returns the corresponding glyph range of the given character range.
  34   // |range| is in text-space (0 corresponds to |GetLayoutText()[0]|). Returned
  35   // value is in run-space (0 corresponds to the first glyph in the run).
  36   Range CharRangeToGlyphRange(const Range& range) const;
  37
  38   // Returns the number of missing glyphs in the shaped text run.
  39   size_t CountMissingGlyphs() const;
  40
  41   // Writes the character and glyph ranges of the cluster containing |pos|.
  42   void GetClusterAt(size_t pos, Range* chars, Range* glyphs) const;
  43
  44   // Returns the grapheme bounds at |text_index|. Handles multi-grapheme glyphs.
  45   Range GetGraphemeBounds(base::i18n::BreakIterator* grapheme_iterator,
  46                           size_t text_index);
  47
  48   // Returns whether the given shaped run contains any missing glyphs.
  49   bool HasMissingGlyphs() const;
  50
  51   float width;
  52   float preceding_run_widths;
  53   Range range;
  54   bool is_rtl;
  55   UBiDiLevel level;
  56   UScriptCode script;
  57
  58   scoped_ptr<uint16[]> glyphs;
  59   scoped_ptr<SkPoint[]> positions;
  60   std::vector<uint32> glyph_to_char;
  61   size_t glyph_count;
  62
  63   skia::RefPtr<SkTypeface> skia_face;
  64   FontRenderParams render_params;
  65   int font_size;
  66   int font_style;
  67   bool strike;
  68   bool diagonal_strike;
  69   bool underline;
  70
  71  private:
  72   DISALLOW_COPY_AND_ASSIGN(TextRunHarfBuzz);
  73 };
  74
  75 }  // namespace internal
  76
  77 class GFX_EXPORT RenderTextHarfBuzz : public RenderText {
  78  public:
  79   RenderTextHarfBuzz();
  80   virtual ~RenderTextHarfBuzz();
  81
  82   // Overridden from RenderText.
  83   virtual Size GetStringSize() OVERRIDE;
  84   virtual SizeF GetStringSizeF() OVERRIDE;
  85   virtual SelectionModel FindCursorPosition(const Point& point) OVERRIDE;
  86   virtual std::vector<FontSpan> GetFontSpansForTesting() OVERRIDE;
  87   virtual Range GetGlyphBounds(size_t index) OVERRIDE;
  88
  89  protected:
  90   // Overridden from RenderText.
  91   virtual int GetLayoutTextBaseline() OVERRIDE;
  92   virtual SelectionModel AdjacentCharSelectionModel(
  93       const SelectionModel& selection,
  94       VisualCursorDirection direction) OVERRIDE;
  95   virtual SelectionModel AdjacentWordSelectionModel(
  96       const SelectionModel& selection,
  97       VisualCursorDirection direction) OVERRIDE;
  98   virtual std::vector<Rect> GetSubstringBounds(const Range& range) OVERRIDE;
  99   virtual size_t TextIndexToLayoutIndex(size_t index) const OVERRIDE;
 100   virtual size_t LayoutIndexToTextIndex(size_t index) const OVERRIDE;
 101   virtual bool IsValidCursorIndex(size_t index) OVERRIDE;
 102   virtual void ResetLayout() OVERRIDE;
 103   virtual void EnsureLayout() OVERRIDE;
 104   virtual void DrawVisualText(Canvas* canvas) OVERRIDE;
 105
 106  private:
 107   friend class RenderTextTest;
 108   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_RunDirection);
 109   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_BreakRunsByUnicodeBlocks);
 110   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_SubglyphGraphemeCases);
 111   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_SubglyphGraphemePartition);
 112   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_NonExistentFont);
 113
 114   // Return the run index that contains the argument; or the length of the
 115   // |runs_| vector if argument exceeds the text length or width.
 116   size_t GetRunContainingCaret(const SelectionModel& caret) const;
 117   size_t GetRunContainingXCoord(int x, int* offset) const;
 118
 119   // Given a |run|, returns the SelectionModel that contains the logical first
 120   // or last caret position inside (not at a boundary of) the run.
 121   // The returned value represents a cursor/caret position without a selection.
 122   SelectionModel FirstSelectionModelInsideRun(
 123       const internal::TextRunHarfBuzz* run);
 124   SelectionModel LastSelectionModelInsideRun(
 125       const internal::TextRunHarfBuzz* run);
 126
 127   // Break the text into logical runs and populate the visual <-> logical maps.
 128   void ItemizeText();
 129
 130   // Shape the glyphs needed for the text |run|.
 131   void ShapeRun(internal::TextRunHarfBuzz* run);
 132   bool ShapeRunWithFont(internal::TextRunHarfBuzz* run,
 133                         const std::string& font);
 134
 135   // Text runs in logical order.
 136   ScopedVector<internal::TextRunHarfBuzz> runs_;
 137
 138   // Maps visual run indices to logical run indices and vice versa.
 139   std::vector<int32_t> visual_to_logical_;
 140   std::vector<int32_t> logical_to_visual_;
 141
 142   bool needs_layout_;
 143
 144   // ICU grapheme iterator for the layout text. Valid when |!needs_layout_|. Can
 145   // be NULL in case of an error.
 146   scoped_ptr<base::i18n::BreakIterator> grapheme_iterator_;
 147
 148   DISALLOW_COPY_AND_ASSIGN(RenderTextHarfBuzz);
 149 };
 150
 151 }  // namespace gfx
 152
 153 #endif  // UI_GFX_RENDER_TEXT_HARFBUZZ_H_