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      1 /*
      2  * Copyright (C) 2007, 2008, 2009, 2011 Apple Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
     14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     15  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     16  * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
     17  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     18  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     19  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
     20  * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     21  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     22  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     23  */
     24 
     25 #ifndef ComplexTextController_h
     26 #define ComplexTextController_h
     27 
     28 #include "wtf/HashSet.h"
     29 #include "wtf/PassRefPtr.h"
     30 #include "wtf/RefCounted.h"
     31 #include "wtf/RetainPtr.h"
     32 #include "wtf/text/WTFString.h"
     33 #include "wtf/unicode/Unicode.h"
     34 #include "wtf/Vector.h"
     35 #include <ApplicationServices/ApplicationServices.h>
     36 
     37 typedef unsigned short CGGlyph;
     38 
     39 typedef const struct __CTRun * CTRunRef;
     40 typedef const struct __CTLine * CTLineRef;
     41 
     42 namespace blink {
     43 
     44 class Font;
     45 class GlyphBuffer;
     46 class SimpleFontData;
     47 class TextRun;
     48 
     49 enum GlyphIterationStyle { IncludePartialGlyphs, ByWholeGlyphs };
     50 
     51 // ComplexTextController is responsible for rendering and measuring glyphs for
     52 // complex scripts on OS X.
     53 class ComplexTextController {
     54 public:
     55     ComplexTextController(const Font*, const TextRun&, bool mayUseNaturalWritingDirection = false, HashSet<const SimpleFontData*>* fallbackFonts = 0, bool forTextEmphasis = false);
     56 
     57     // Advance and emit glyphs up to the specified character.
     58     void advance(unsigned to, GlyphBuffer* = 0, GlyphIterationStyle = IncludePartialGlyphs, HashSet<const SimpleFontData*>* fallbackFonts = 0);
     59 
     60     // Compute the character offset for a given x coordinate.
     61     int offsetForPosition(float x, bool includePartialGlyphs);
     62 
     63     // Returns the width of everything we've consumed so far.
     64     float runWidthSoFar() const { return m_runWidthSoFar; }
     65 
     66     float totalWidth() const { return m_totalWidth; }
     67 
     68     float minGlyphBoundingBoxX() const { return m_minGlyphBoundingBoxX; }
     69     float maxGlyphBoundingBoxX() const { return m_maxGlyphBoundingBoxX; }
     70     float minGlyphBoundingBoxY() const { return m_minGlyphBoundingBoxY; }
     71     float maxGlyphBoundingBoxY() const { return m_maxGlyphBoundingBoxY; }
     72 
     73 private:
     74     class ComplexTextRun : public RefCounted<ComplexTextRun> {
     75     public:
     76         static PassRefPtr<ComplexTextRun> create(CTRunRef ctRun, const SimpleFontData* fontData, const UChar* characters, unsigned stringLocation, size_t stringLength, CFRange runRange)
     77         {
     78             return adoptRef(new ComplexTextRun(ctRun, fontData, characters, stringLocation, stringLength, runRange));
     79         }
     80 
     81         static PassRefPtr<ComplexTextRun> create(const SimpleFontData* fontData, const UChar* characters, unsigned stringLocation, size_t stringLength, bool ltr)
     82         {
     83             return adoptRef(new ComplexTextRun(fontData, characters, stringLocation, stringLength, ltr));
     84         }
     85 
     86         unsigned glyphCount() const { return m_glyphCount; }
     87         const SimpleFontData* fontData() const { return m_fontData; }
     88         const UChar* characters() const { return m_characters; }
     89         unsigned stringLocation() const { return m_stringLocation; }
     90         size_t stringLength() const { return m_stringLength; }
     91         ALWAYS_INLINE CFIndex indexAt(size_t i) const;
     92         CFIndex indexBegin() const { return m_indexBegin; }
     93         CFIndex indexEnd() const { return m_indexEnd; }
     94         CFIndex endOffsetAt(size_t i) const { ASSERT(!m_isMonotonic); return m_glyphEndOffsets[i]; }
     95         const CGGlyph* glyphs() const { return m_glyphs; }
     96         const CGSize* advances() const { return m_advances; }
     97         bool isLTR() const { return m_isLTR; }
     98         bool isMonotonic() const { return m_isMonotonic; }
     99         void setIsNonMonotonic();
    100 
    101     private:
    102         ComplexTextRun(CTRunRef, const SimpleFontData*, const UChar* characters, unsigned stringLocation, size_t stringLength, CFRange runRange);
    103         ComplexTextRun(const SimpleFontData*, const UChar* characters, unsigned stringLocation, size_t stringLength, bool ltr);
    104 
    105         unsigned m_glyphCount;
    106         const SimpleFontData* m_fontData;
    107         const UChar* m_characters;
    108         unsigned m_stringLocation;
    109         size_t m_stringLength;
    110         Vector<CFIndex, 64> m_coreTextIndicesVector;
    111         const CFIndex* m_coreTextIndices;
    112         CFIndex m_indexBegin;
    113         CFIndex m_indexEnd;
    114         Vector<CFIndex, 64> m_glyphEndOffsets;
    115         Vector<CGGlyph, 64> m_glyphsVector;
    116         const CGGlyph* m_glyphs;
    117         Vector<CGSize, 64> m_advancesVector;
    118         const CGSize* m_advances;
    119         bool m_isLTR;
    120         bool m_isMonotonic;
    121     };
    122 
    123     static unsigned stringBegin(const ComplexTextRun& run) { return run.stringLocation() + run.indexBegin(); }
    124     static unsigned stringEnd(const ComplexTextRun& run) { return run.stringLocation() + run.indexEnd(); }
    125 
    126     void collectComplexTextRuns();
    127 
    128     void collectComplexTextRunsForCharacters(const UChar*, unsigned length, unsigned stringLocation, const SimpleFontData*);
    129     void adjustGlyphsAndAdvances();
    130 
    131     unsigned findNextRunIndex(unsigned runIndex) const;
    132     unsigned indexOfCurrentRun(unsigned& leftmostGlyph);
    133     unsigned incrementCurrentRun(unsigned& leftmostGlyph);
    134 
    135     // The initial capacity of these vectors was selected as being the smallest power of two greater than
    136     // the average (3.5) plus one standard deviation (7.5) of nonzero sizes used on Arabic Wikipedia.
    137     Vector<unsigned, 16> m_runIndices;
    138     Vector<unsigned, 16> m_glyphCountFromStartToIndex;
    139 
    140     const Font& m_font;
    141     const TextRun& m_run;
    142     bool m_isLTROnly;
    143     bool m_mayUseNaturalWritingDirection;
    144     bool m_forTextEmphasis;
    145 
    146     Vector<String> m_stringsFor8BitRuns;
    147     Vector<UChar, 256> m_smallCapsBuffer;
    148 
    149     // Retain lines rather than their runs for better performance.
    150     Vector<RetainPtr<CTLineRef> > m_coreTextLines;
    151     Vector<RefPtr<ComplexTextRun>, 16> m_complexTextRuns;
    152     Vector<CGSize, 256> m_adjustedAdvances;
    153     Vector<CGGlyph, 256> m_adjustedGlyphs;
    154 
    155     unsigned m_currentCharacter;
    156     int m_end;
    157 
    158     CGFloat m_totalWidth;
    159 
    160     float m_runWidthSoFar;
    161     unsigned m_numGlyphsSoFar;
    162     size_t m_currentRun;
    163     unsigned m_glyphInCurrentRun;
    164     unsigned m_characterInCurrentGlyph;
    165     float m_expansion;
    166     float m_expansionPerOpportunity;
    167     float m_leadingExpansion;
    168     bool m_afterExpansion;
    169 
    170     HashSet<const SimpleFontData*>* m_fallbackFonts;
    171 
    172     float m_minGlyphBoundingBoxX;
    173     float m_maxGlyphBoundingBoxX;
    174     float m_minGlyphBoundingBoxY;
    175     float m_maxGlyphBoundingBoxY;
    176 };
    177 
    178 } // namespace blink
    179 
    180 #endif // ComplexTextController_h
    181