Home | History | Annotate | Download | only in mac 
      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 WebCore {
     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 finalRoundingWidth() const { return m_finalRoundingWidth; }
     69 
     70     float minGlyphBoundingBoxX() const { return m_minGlyphBoundingBoxX; }
     71     float maxGlyphBoundingBoxX() const { return m_maxGlyphBoundingBoxX; }
     72     float minGlyphBoundingBoxY() const { return m_minGlyphBoundingBoxY; }
     73     float maxGlyphBoundingBoxY() const { return m_maxGlyphBoundingBoxY; }
     74 
     75 private:
     76     class ComplexTextRun : public RefCounted<ComplexTextRun> {
     77     public:
     78         static PassRefPtr<ComplexTextRun> create(CTRunRef ctRun, const SimpleFontData* fontData, const UChar* characters, unsigned stringLocation, size_t stringLength, CFRange runRange)
     79         {
     80             return adoptRef(new ComplexTextRun(ctRun, fontData, characters, stringLocation, stringLength, runRange));
     81         }
     82 
     83         static PassRefPtr<ComplexTextRun> create(const SimpleFontData* fontData, const UChar* characters, unsigned stringLocation, size_t stringLength, bool ltr)
     84         {
     85             return adoptRef(new ComplexTextRun(fontData, characters, stringLocation, stringLength, ltr));
     86         }
     87 
     88         unsigned glyphCount() const { return m_glyphCount; }
     89         const SimpleFontData* fontData() const { return m_fontData; }
     90         const UChar* characters() const { return m_characters; }
     91         unsigned stringLocation() const { return m_stringLocation; }
     92         size_t stringLength() const { return m_stringLength; }
     93         ALWAYS_INLINE CFIndex indexAt(size_t i) const;
     94         CFIndex indexBegin() const { return m_indexBegin; }
     95         CFIndex indexEnd() const { return m_indexEnd; }
     96         CFIndex endOffsetAt(size_t i) const { ASSERT(!m_isMonotonic); return m_glyphEndOffsets[i]; }
     97         const CGGlyph* glyphs() const { return m_glyphs; }
     98         const CGSize* advances() const { return m_advances; }
     99         bool isLTR() const { return m_isLTR; }
    100         bool isMonotonic() const { return m_isMonotonic; }
    101         void setIsNonMonotonic();
    102 
    103     private:
    104         ComplexTextRun(CTRunRef, const SimpleFontData*, const UChar* characters, unsigned stringLocation, size_t stringLength, CFRange runRange);
    105         ComplexTextRun(const SimpleFontData*, const UChar* characters, unsigned stringLocation, size_t stringLength, bool ltr);
    106 
    107         unsigned m_glyphCount;
    108         const SimpleFontData* m_fontData;
    109         const UChar* m_characters;
    110         unsigned m_stringLocation;
    111         size_t m_stringLength;
    112         Vector<CFIndex, 64> m_coreTextIndicesVector;
    113         const CFIndex* m_coreTextIndices;
    114         CFIndex m_indexBegin;
    115         CFIndex m_indexEnd;
    116         Vector<CFIndex, 64> m_glyphEndOffsets;
    117         Vector<CGGlyph, 64> m_glyphsVector;
    118         const CGGlyph* m_glyphs;
    119         Vector<CGSize, 64> m_advancesVector;
    120         const CGSize* m_advances;
    121         bool m_isLTR;
    122         bool m_isMonotonic;
    123     };
    124 
    125     static unsigned stringBegin(const ComplexTextRun& run) { return run.stringLocation() + run.indexBegin(); }
    126     static unsigned stringEnd(const ComplexTextRun& run) { return run.stringLocation() + run.indexEnd(); }
    127 
    128     void collectComplexTextRuns();
    129 
    130     void collectComplexTextRunsForCharacters(const UChar*, unsigned length, unsigned stringLocation, const SimpleFontData*);
    131     void adjustGlyphsAndAdvances();
    132 
    133     unsigned findNextRunIndex(unsigned runIndex) const;
    134     unsigned indexOfCurrentRun(unsigned& leftmostGlyph);
    135     unsigned incrementCurrentRun(unsigned& leftmostGlyph);
    136 
    137     // The initial capacity of these vectors was selected as being the smallest power of two greater than
    138     // the average (3.5) plus one standard deviation (7.5) of nonzero sizes used on Arabic Wikipedia.
    139     Vector<unsigned, 16> m_runIndices;
    140     Vector<unsigned, 16> m_glyphCountFromStartToIndex;
    141 
    142     const Font& m_font;
    143     const TextRun& m_run;
    144     bool m_isLTROnly;
    145     bool m_mayUseNaturalWritingDirection;
    146     bool m_forTextEmphasis;
    147 
    148     Vector<String> m_stringsFor8BitRuns;
    149     Vector<UChar, 256> m_smallCapsBuffer;
    150 
    151     // Retain lines rather than their runs for better performance.
    152     Vector<RetainPtr<CTLineRef> > m_coreTextLines;
    153     Vector<RefPtr<ComplexTextRun>, 16> m_complexTextRuns;
    154     Vector<CGSize, 256> m_adjustedAdvances;
    155     Vector<CGGlyph, 256> m_adjustedGlyphs;
    156 
    157     unsigned m_currentCharacter;
    158     int m_end;
    159 
    160     CGFloat m_totalWidth;
    161 
    162     float m_runWidthSoFar;
    163     unsigned m_numGlyphsSoFar;
    164     size_t m_currentRun;
    165     unsigned m_glyphInCurrentRun;
    166     unsigned m_characterInCurrentGlyph;
    167     float m_finalRoundingWidth;
    168     float m_expansion;
    169     float m_expansionPerOpportunity;
    170     float m_leadingExpansion;
    171     bool m_afterExpansion;
    172 
    173     HashSet<const SimpleFontData*>* m_fallbackFonts;
    174 
    175     float m_minGlyphBoundingBoxX;
    176     float m_maxGlyphBoundingBoxX;
    177     float m_minGlyphBoundingBoxY;
    178     float m_maxGlyphBoundingBoxY;
    179 
    180     unsigned m_lastRoundingGlyph;
    181 };
    182 
    183 } // namespace WebCore
    184 
    185 #endif // ComplexTextController_h
    186