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 struct GFX_EXPORT TextRunHarfBuzz {
  29   TextRunHarfBuzz();
  30   ~TextRunHarfBuzz();
  31
  32   // Returns the index of the first glyph that corresponds to the character at
  33   // |pos|.
  34   size_t CharToGlyph(size_t pos) const;
  35
  36   // Returns the corresponding glyph range of the given character range.
  37   // |range| is in text-space (0 corresponds to |GetDisplayText()[0]|). Returned
  38   // value is in run-space (0 corresponds to the first glyph in the run).
  39   Range CharRangeToGlyphRange(const Range& range) const;
  40
  41   // Returns the number of missing glyphs in the shaped text run.
  42   size_t CountMissingGlyphs() const;
  43
  44   // Writes the character and glyph ranges of the cluster containing |pos|.
  45   void GetClusterAt(size_t pos, Range* chars, Range* glyphs) const;
  46
  47   // Returns the grapheme bounds at |text_index|. Handles multi-grapheme glyphs.
  48   RangeF GetGraphemeBounds(base::i18n::BreakIterator* grapheme_iterator,
  49                            size_t text_index);
  50
  51   // Returns whether the given shaped run contains any missing glyphs.
  52   bool HasMissingGlyphs() const;
  53
  54   // Returns the glyph width for the given character range. |char_range| is in
  55   // text-space (0 corresponds to |GetDisplayText()[0]|).
  56   SkScalar GetGlyphWidthForCharRange(const Range& char_range) const;
  57
  58   float width;
  59   float preceding_run_widths;
  60   Range range;
  61   bool is_rtl;
  62   UBiDiLevel level;
  63   UScriptCode script;
  64
  65   scoped_ptr<uint16[]> glyphs;
  66   scoped_ptr<SkPoint[]> positions;
  67   std::vector<uint32> glyph_to_char;
  68   size_t glyph_count;
  69
  70   std::string family;
  71   skia::RefPtr<SkTypeface> skia_face;
  72   FontRenderParams render_params;
  73   int font_size;
  74   int baseline_offset;
  75   int baseline_type;
  76   int font_style;
  77   bool strike;
  78   bool diagonal_strike;
  79   bool underline;
  80
  81  private:
  82   DISALLOW_COPY_AND_ASSIGN(TextRunHarfBuzz);
  83 };
  84
  85 // Manages the list of TextRunHarfBuzz and its logical <-> visual index mapping.
  86 class TextRunList {
  87  public:
  88   TextRunList();
  89   ~TextRunList();
  90
  91   size_t size() const { return runs_.size(); }
  92
  93   // Converts the index between logical and visual index.
  94   size_t visual_to_logical(size_t index) const {
  95     return visual_to_logical_[index];
  96   }
  97   size_t logical_to_visual(size_t index) const {
  98     return logical_to_visual_[index];
  99   }
 100
 101   const ScopedVector<TextRunHarfBuzz>& runs() const { return runs_; }
 102
 103   // Adds the new |run| to the run list.
 104   void add(TextRunHarfBuzz* run) { runs_.push_back(run); }
 105
 106   // Reset the run list.
 107   void Reset();
 108
 109   // Initialize the index mapping.
 110   void InitIndexMap();
 111
 112   // Precomputes the offsets for all runs.
 113   void ComputePrecedingRunWidths();
 114
 115   // Get the total width of runs, as if they were shown on one line.
 116   // Do not use this when multiline is enabled.
 117   float width() const { return width_; }
 118
 119   // Get the run index applicable to |position| (at or preceeding |position|).
 120   size_t GetRunIndexAt(size_t position) const;
 121
 122  private:
 123   // Text runs in logical order.
 124   ScopedVector<TextRunHarfBuzz> runs_;
 125
 126   // Maps visual run indices to logical run indices and vice versa.
 127   std::vector<int32_t> visual_to_logical_;
 128   std::vector<int32_t> logical_to_visual_;
 129
 130   float width_;
 131
 132   DISALLOW_COPY_AND_ASSIGN(TextRunList);
 133 };
 134
 135 }  // namespace internal
 136
 137 class GFX_EXPORT RenderTextHarfBuzz : public RenderText {
 138  public:
 139   RenderTextHarfBuzz();
 140   ~RenderTextHarfBuzz() override;
 141
 142   // RenderText:
 143   scoped_ptr<RenderText> CreateInstanceOfSameType() const override;
 144   bool MultilineSupported() const override;
 145   const base::string16& GetDisplayText() override;
 146   Size GetStringSize() override;
 147   SizeF GetStringSizeF() override;
 148   SelectionModel FindCursorPosition(const Point& point) override;
 149   std::vector<FontSpan> GetFontSpansForTesting() override;
 150   Range GetGlyphBounds(size_t index) override;
 151
 152  protected:
 153   // RenderText:
 154   int GetDisplayTextBaseline() override;
 155   SelectionModel AdjacentCharSelectionModel(
 156       const SelectionModel& selection,
 157       VisualCursorDirection direction) override;
 158   SelectionModel AdjacentWordSelectionModel(
 159       const SelectionModel& selection,
 160       VisualCursorDirection direction) override;
 161   std::vector<Rect> GetSubstringBounds(const Range& range) override;
 162   size_t TextIndexToDisplayIndex(size_t index) override;
 163   size_t DisplayIndexToTextIndex(size_t index) override;
 164   bool IsValidCursorIndex(size_t index) override;
 165   void OnLayoutTextAttributeChanged(bool text_changed) override;
 166   void OnDisplayTextAttributeChanged() override;
 167   void EnsureLayout() override;
 168   void DrawVisualText(Canvas* canvas) override;
 169
 170  private:
 171   friend class RenderTextTest;
 172   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, Multiline_HorizontalAlignment);
 173   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, Multiline_NormalWidth);
 174   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, Multiline_WordWrapBehavior);
 175   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_RunDirection);
 176   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_HorizontalPositions);
 177   FRIEND_TEST_ALL_PREFIXES(RenderTextTest,
 178                            HarfBuzz_TextPositionWithFractionalSize);
 179   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_BreakRunsByUnicodeBlocks);
 180   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_BreakRunsByEmoji);
 181   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_SubglyphGraphemeCases);
 182   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_SubglyphGraphemePartition);
 183   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_NonExistentFont);
 184   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_UniscribeFallback);
 185   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_UnicodeFallback);
 186   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, Multiline_LineBreakerBehavior);
 187   FRIEND_TEST_ALL_PREFIXES(RenderTextTest,
 188                            Multiline_SurrogatePairsOrCombiningChars);
 189   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, Multiline_ZeroWidthChars);
 190
 191   // Specify the width of a glyph for test. The width of glyphs is very
 192   // platform-dependent and environment-dependent. Otherwise multiline test
 193   // will become really flaky.
 194   void set_glyph_width_for_test(float test_width) {
 195     glyph_width_for_test_ = test_width;
 196   }
 197
 198   // The actual implementation of the text drawing.
 199   void DrawVisualTextInternal(internal::SkiaTextRenderer* renderer);
 200
 201   // Return the run index that contains the argument; or the length of the
 202   // |runs_| vector if argument exceeds the text length or width.
 203   size_t GetRunContainingCaret(const SelectionModel& caret);
 204   size_t GetRunContainingXCoord(float x, float* offset) const;
 205
 206   // Given a |run|, returns the SelectionModel that contains the logical first
 207   // or last caret position inside (not at a boundary of) the run.
 208   // The returned value represents a cursor/caret position without a selection.
 209   SelectionModel FirstSelectionModelInsideRun(
 210       const internal::TextRunHarfBuzz* run);
 211   SelectionModel LastSelectionModelInsideRun(
 212       const internal::TextRunHarfBuzz* run);
 213
 214   // Break the text into logical runs and populate the visual <-> logical maps
 215   // into |run_list_out|.
 216   void ItemizeTextToRuns(const base::string16& string,
 217                          internal::TextRunList* run_list_out);
 218
 219   // Helper method for ShapeRun() that calls ShapeRunWithFont() with |text|,
 220   // |run|, |family|, and |render_params|, returning true if the family provides
 221   // all the glyphs needed for |run|, and false otherwise. Additionally updates
 222   // |best_family|, |best_render_params|, and |best_missing_glyphs| if |family|
 223   // has fewer than |best_missing_glyphs| missing glyphs.
 224   bool CompareFamily(const base::string16& text,
 225                      const std::string& family,
 226                      const gfx::FontRenderParams& render_params,
 227                      internal::TextRunHarfBuzz* run,
 228                      std::string* best_family,
 229                      gfx::FontRenderParams* best_render_params,
 230                      size_t* best_missing_glyphs);
 231
 232   // Shape the glyphs of all runs in |run_list| using |text|.
 233   void ShapeRunList(const base::string16& text,
 234                     internal::TextRunList* run_list);
 235
 236   // Shape the glyphs needed for the |run| within the |text|.
 237   void ShapeRun(const base::string16& text,
 238                 internal::TextRunHarfBuzz* run);
 239   bool ShapeRunWithFont(const base::string16& text,
 240                         const std::string& font_family,
 241                         const FontRenderParams& params,
 242                         internal::TextRunHarfBuzz* run);
 243
 244   // Makes sure that text runs for layout text are shaped.
 245   void EnsureLayoutRunList();
 246
 247   // ICU grapheme iterator for the layout text. Can be NULL in case of an error.
 248   base::i18n::BreakIterator* GetGraphemeIterator();
 249
 250   // Returns the current run list, |display_run_list_| if the text is
 251   // elided, or |layout_run_list_| otherwise.
 252   internal::TextRunList* GetRunList();
 253   const internal::TextRunList* GetRunList() const;
 254
 255   // Text run list for |layout_text_| and |display_text_|.
 256   // |display_run_list_| is created only when the text is elided.
 257   internal::TextRunList layout_run_list_;
 258   scoped_ptr<internal::TextRunList> display_run_list_;
 259
 260   bool update_layout_run_list_ : 1;
 261   bool update_display_run_list_ : 1;
 262   bool update_grapheme_iterator_ : 1;
 263   bool update_display_text_ : 1;
 264
 265   // ICU grapheme iterator for the layout text. Use GetGraphemeIterator()
 266   // to access the iterator.
 267   scoped_ptr<base::i18n::BreakIterator> grapheme_iterator_;
 268
 269   // The total size of the layouted text.
 270   SizeF total_size_;
 271
 272   // Fixed width of glyphs. This should only be set in test environments.
 273   float glyph_width_for_test_;
 274
 275   DISALLOW_COPY_AND_ASSIGN(RenderTextHarfBuzz);
 276 };
 277
 278 }  // namespace gfx
 279
 280 #endif  // UI_GFX_RENDER_TEXT_HARFBUZZ_H_