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   std::string family;
  64   skia::RefPtr<SkTypeface> skia_face;
  65   FontRenderParams render_params;
  66   int font_size;
  67   int font_style;
  68   bool strike;
  69   bool diagonal_strike;
  70   bool underline;
  71
  72  private:
  73   DISALLOW_COPY_AND_ASSIGN(TextRunHarfBuzz);
  74 };
  75
  76 }  // namespace internal
  77
  78 class GFX_EXPORT RenderTextHarfBuzz : public RenderText {
  79  public:
  80   RenderTextHarfBuzz();
  81   ~RenderTextHarfBuzz() override;
  82
  83   // Overridden from RenderText.
  84   Size GetStringSize() override;
  85   SizeF GetStringSizeF() override;
  86   SelectionModel FindCursorPosition(const Point& point) override;
  87   std::vector<FontSpan> GetFontSpansForTesting() override;
  88   Range GetGlyphBounds(size_t index) override;
  89
  90  protected:
  91   // Overridden from RenderText.
  92   int GetLayoutTextBaseline() override;
  93   SelectionModel AdjacentCharSelectionModel(
  94       const SelectionModel& selection,
  95       VisualCursorDirection direction) override;
  96   SelectionModel AdjacentWordSelectionModel(
  97       const SelectionModel& selection,
  98       VisualCursorDirection direction) override;
  99   std::vector<Rect> GetSubstringBounds(const Range& range) override;
 100   size_t TextIndexToLayoutIndex(size_t index) const override;
 101   size_t LayoutIndexToTextIndex(size_t index) const override;
 102   bool IsValidCursorIndex(size_t index) override;
 103   void ResetLayout() override;
 104   void EnsureLayout() override;
 105   void DrawVisualText(Canvas* canvas) override;
 106
 107  private:
 108   friend class RenderTextTest;
 109   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_RunDirection);
 110   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_BreakRunsByUnicodeBlocks);
 111   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_SubglyphGraphemeCases);
 112   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_SubglyphGraphemePartition);
 113   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_NonExistentFont);
 114   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_UniscribeFallback);
 115
 116   // Return the run index that contains the argument; or the length of the
 117   // |runs_| vector if argument exceeds the text length or width.
 118   size_t GetRunContainingCaret(const SelectionModel& caret) const;
 119   size_t GetRunContainingXCoord(int x, int* offset) const;
 120
 121   // Given a |run|, returns the SelectionModel that contains the logical first
 122   // or last caret position inside (not at a boundary of) the run.
 123   // The returned value represents a cursor/caret position without a selection.
 124   SelectionModel FirstSelectionModelInsideRun(
 125       const internal::TextRunHarfBuzz* run);
 126   SelectionModel LastSelectionModelInsideRun(
 127       const internal::TextRunHarfBuzz* run);
 128
 129   // Break the text into logical runs and populate the visual <-> logical maps.
 130   void ItemizeText();
 131
 132   // Helper method for ShapeRun() that calls ShapeRunWithFont() with |run|,
 133   // |family|, and |render_params|, returning true if the family provides all
 134   // needed glyphs and false otherwise. Additionally updates |best_family|,
 135   // |best_render_params|, and |best_missing_glyphs| if |family| has fewer than
 136   // |best_missing_glyphs| missing glyphs.
 137   bool CompareFamily(internal::TextRunHarfBuzz* run,
 138                      const std::string& family,
 139                      const gfx::FontRenderParams& render_params,
 140                      std::string* best_family,
 141                      gfx::FontRenderParams* best_render_params,
 142                      size_t* best_missing_glyphs);
 143
 144   // Shape the glyphs needed for the text |run|.
 145   void ShapeRun(internal::TextRunHarfBuzz* run);
 146   bool ShapeRunWithFont(internal::TextRunHarfBuzz* run,
 147                         const std::string& font_family,
 148                         const FontRenderParams& params);
 149
 150   // Text runs in logical order.
 151   ScopedVector<internal::TextRunHarfBuzz> runs_;
 152
 153   // Maps visual run indices to logical run indices and vice versa.
 154   std::vector<int32_t> visual_to_logical_;
 155   std::vector<int32_t> logical_to_visual_;
 156
 157   bool needs_layout_;
 158
 159   // ICU grapheme iterator for the layout text. Valid when |!needs_layout_|. Can
 160   // be NULL in case of an error.
 161   scoped_ptr<base::i18n::BreakIterator> grapheme_iterator_;
 162
 163   DISALLOW_COPY_AND_ASSIGN(RenderTextHarfBuzz);
 164 };
 165
 166 }  // namespace gfx
 167
 168 #endif  // UI_GFX_RENDER_TEXT_HARFBUZZ_H_