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 class Range;
  24 class RangeF;
  25
  26 namespace internal {
  27
  28 // Applies std::round to the start and end values of the given RangeF.
  29 GFX_EXPORT Range RoundRangeF(const RangeF& range_f);
  30
  31 struct GFX_EXPORT TextRunHarfBuzz {
  32   TextRunHarfBuzz();
  33   ~TextRunHarfBuzz();
  34
  35   // Returns the index of the first glyph that corresponds to the character at
  36   // |pos|.
  37   size_t CharToGlyph(size_t pos) const;
  38
  39   // Returns the corresponding glyph range of the given character range.
  40   // |range| is in text-space (0 corresponds to |GetDisplayText()[0]|). Returned
  41   // value is in run-space (0 corresponds to the first glyph in the run).
  42   Range CharRangeToGlyphRange(const Range& range) const;
  43
  44   // Returns the number of missing glyphs in the shaped text run.
  45   size_t CountMissingGlyphs() const;
  46
  47   // Writes the character and glyph ranges of the cluster containing |pos|.
  48   void GetClusterAt(size_t pos, Range* chars, Range* glyphs) const;
  49
  50   // Returns the grapheme bounds at |text_index|. Handles multi-grapheme glyphs.
  51   RangeF GetGraphemeBounds(base::i18n::BreakIterator* grapheme_iterator,
  52                            size_t text_index);
  53
  54   // Returns whether the given shaped run contains any missing glyphs.
  55   bool HasMissingGlyphs() const;
  56
  57   float width;
  58   float preceding_run_widths;
  59   Range range;
  60   bool is_rtl;
  61   UBiDiLevel level;
  62   UScriptCode script;
  63
  64   scoped_ptr<uint16[]> glyphs;
  65   scoped_ptr<SkPoint[]> positions;
  66   std::vector<uint32> glyph_to_char;
  67   size_t glyph_count;
  68
  69   std::string family;
  70   skia::RefPtr<SkTypeface> skia_face;
  71   FontRenderParams render_params;
  72   int font_size;
  73   int baseline_offset;
  74   int baseline_type;
  75   int font_style;
  76   bool strike;
  77   bool diagonal_strike;
  78   bool underline;
  79
  80  private:
  81   DISALLOW_COPY_AND_ASSIGN(TextRunHarfBuzz);
  82 };
  83
  84 // Manages the list of TextRunHarfBuzz and its logical <-> visual index mapping.
  85 class TextRunList {
  86  public:
  87   TextRunList();
  88   ~TextRunList();
  89
  90   size_t size() const { return runs_.size(); }
  91
  92   // Converts the index between logical and visual index.
  93   size_t visual_to_logical(size_t index) const {
  94     return visual_to_logical_[index];
  95   }
  96   size_t logical_to_visual(size_t index) const {
  97     return logical_to_visual_[index];
  98   }
  99
 100   const ScopedVector<TextRunHarfBuzz>& runs() const { return runs_; }
 101
 102   // Adds the new |run| to the run list.
 103   void add(TextRunHarfBuzz* run) { runs_.push_back(run); }
 104
 105   // Reset the run list.
 106   void Reset();
 107
 108   // Initialize the index mapping.
 109   void InitIndexMap();
 110
 111   // Precomputes the offsets for all runs.
 112   void ComputePrecedingRunWidths();
 113
 114   // Get the total width of runs, as if they were shown on one line.
 115   // Do not use this when multiline is enabled.
 116   float width() const { return width_; }
 117
 118  private:
 119   // Text runs in logical order.
 120   ScopedVector<TextRunHarfBuzz> runs_;
 121
 122   // Maps visual run indices to logical run indices and vice versa.
 123   std::vector<int32_t> visual_to_logical_;
 124   std::vector<int32_t> logical_to_visual_;
 125
 126   float width_;
 127
 128   DISALLOW_COPY_AND_ASSIGN(TextRunList);
 129 };
 130
 131 }  // namespace internal
 132
 133 class GFX_EXPORT RenderTextHarfBuzz : public RenderText {
 134  public:
 135   RenderTextHarfBuzz();
 136   ~RenderTextHarfBuzz() override;
 137
 138   // RenderText:
 139   scoped_ptr<RenderText> CreateInstanceOfSameType() const override;
 140   bool MultilineSupported() const override;
 141   const base::string16& GetDisplayText() override;
 142   Size GetStringSize() override;
 143   SizeF GetStringSizeF() override;
 144   SelectionModel FindCursorPosition(const Point& point) override;
 145   std::vector<FontSpan> GetFontSpansForTesting() override;
 146   Range GetGlyphBounds(size_t index) override;
 147
 148  protected:
 149   // RenderText:
 150   int GetDisplayTextBaseline() override;
 151   SelectionModel AdjacentCharSelectionModel(
 152       const SelectionModel& selection,
 153       VisualCursorDirection direction) override;
 154   SelectionModel AdjacentWordSelectionModel(
 155       const SelectionModel& selection,
 156       VisualCursorDirection direction) override;
 157   std::vector<Rect> GetSubstringBounds(const Range& range) override;
 158   size_t TextIndexToDisplayIndex(size_t index) override;
 159   size_t DisplayIndexToTextIndex(size_t index) override;
 160   bool IsValidCursorIndex(size_t index) override;
 161   void OnLayoutTextAttributeChanged(bool text_changed) override;
 162   void OnDisplayTextAttributeChanged() override;
 163   void EnsureLayout() override;
 164   void DrawVisualText(Canvas* canvas) override;
 165
 166  private:
 167   friend class RenderTextTest;
 168   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, Multiline_HorizontalAlignment);
 169   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, Multiline_NormalWidth);
 170   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, Multiline_WordWrapBehavior);
 171   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_RunDirection);
 172   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_HorizontalPositions);
 173   FRIEND_TEST_ALL_PREFIXES(RenderTextTest,
 174                            HarfBuzz_TextPositionWithFractionalSize);
 175   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_BreakRunsByUnicodeBlocks);
 176   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_BreakRunsByEmoji);
 177   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_SubglyphGraphemeCases);
 178   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_SubglyphGraphemePartition);
 179   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_NonExistentFont);
 180   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_UniscribeFallback);
 181   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_UnicodeFallback);
 182
 183   // Specify the width of a glyph for test. The width of glyphs is very
 184   // platform-dependent and environment-dependent. Otherwise multiline test
 185   // will become really flaky.
 186   void set_glyph_width_for_test(float test_width) {
 187     glyph_width_for_test_ = test_width;
 188   }
 189
 190   // The actual implementation of the text drawing.
 191   void DrawVisualTextInternal(internal::SkiaTextRenderer* renderer);
 192
 193   // Return the run index that contains the argument; or the length of the
 194   // |runs_| vector if argument exceeds the text length or width.
 195   size_t GetRunContainingCaret(const SelectionModel& caret);
 196   size_t GetRunContainingXCoord(float x, float* offset) const;
 197
 198   // Given a |run|, returns the SelectionModel that contains the logical first
 199   // or last caret position inside (not at a boundary of) the run.
 200   // The returned value represents a cursor/caret position without a selection.
 201   SelectionModel FirstSelectionModelInsideRun(
 202       const internal::TextRunHarfBuzz* run);
 203   SelectionModel LastSelectionModelInsideRun(
 204       const internal::TextRunHarfBuzz* run);
 205
 206   // Break the text into logical runs and populate the visual <-> logical maps
 207   // into |run_list_out|.
 208   void ItemizeTextToRuns(const base::string16& string,
 209                          internal::TextRunList* run_list_out);
 210
 211   // Helper method for ShapeRun() that calls ShapeRunWithFont() with |text|,
 212   // |run|, |family|, and |render_params|, returning true if the family provides
 213   // all the glyphs needed for |run|, and false otherwise. Additionally updates
 214   // |best_family|, |best_render_params|, and |best_missing_glyphs| if |family|
 215   // has fewer than |best_missing_glyphs| missing glyphs.
 216   bool CompareFamily(const base::string16& text,
 217                      const std::string& family,
 218                      const gfx::FontRenderParams& render_params,
 219                      internal::TextRunHarfBuzz* run,
 220                      std::string* best_family,
 221                      gfx::FontRenderParams* best_render_params,
 222                      size_t* best_missing_glyphs);
 223
 224   // Shape the glyphs of all runs in |run_list| using |text|.
 225   void ShapeRunList(const base::string16& text,
 226                     internal::TextRunList* run_list);
 227
 228   // Shape the glyphs needed for the |run| within the |text|.
 229   void ShapeRun(const base::string16& text,
 230                 internal::TextRunHarfBuzz* run);
 231   bool ShapeRunWithFont(const base::string16& text,
 232                         const std::string& font_family,
 233                         const FontRenderParams& params,
 234                         internal::TextRunHarfBuzz* run);
 235
 236   // Makes sure that text runs for layout text are shaped.
 237   void EnsureLayoutRunList();
 238
 239   // ICU grapheme iterator for the layout text. Can be NULL in case of an error.
 240   base::i18n::BreakIterator* GetGraphemeIterator();
 241
 242   // Returns the current run list, |display_run_list_| if the text is
 243   // elided, or |layout_run_list_| otherwise.
 244   internal::TextRunList* GetRunList();
 245   const internal::TextRunList* GetRunList() const;
 246
 247   // Text run list for |layout_text_| and |display_text_|.
 248   // |display_run_list_| is created only when the text is elided.
 249   internal::TextRunList layout_run_list_;
 250   scoped_ptr<internal::TextRunList> display_run_list_;
 251
 252   bool update_layout_run_list_ : 1;
 253   bool update_display_run_list_ : 1;
 254   bool update_grapheme_iterator_ : 1;
 255   bool update_display_text_ : 1;
 256
 257   // ICU grapheme iterator for the layout text. Use GetGraphemeIterator()
 258   // to access the iterator.
 259   scoped_ptr<base::i18n::BreakIterator> grapheme_iterator_;
 260
 261   // The total size of the layouted text.
 262   SizeF total_size_;
 263
 264   // Fixed width of glyphs. This should only be set in test environments.
 265   float glyph_width_for_test_;
 266
 267   DISALLOW_COPY_AND_ASSIGN(RenderTextHarfBuzz);
 268 };
 269
 270 }  // namespace gfx
 271
 272 #endif  // UI_GFX_RENDER_TEXT_HARFBUZZ_H_