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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 "platform/fonts/GlyphBuffer.h"
29 #include "wtf/HashSet.h"
30 #include "wtf/PassRefPtr.h"
31 #include "wtf/RefCounted.h"
32 #include "wtf/RetainPtr.h"
33 #include "wtf/text/WTFString.h"
34 #include "wtf/unicode/Unicode.h"
35 #include "wtf/Vector.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 SimpleFontData;
46 class TextRun;
47 
48 enum GlyphIterationStyle { IncludePartialGlyphs, ByWholeGlyphs };
49 
50 // ComplexTextController is responsible for rendering and measuring glyphs for
51 // complex scripts on OS X.
52 class ComplexTextController {
53 public:
54     ComplexTextController(const Font*, const TextRun&, bool mayUseNaturalWritingDirection = false, HashSet<const SimpleFontData*>* fallbackFonts = 0, bool forTextEmphasis = false);
55 
56     // Advance and emit glyphs up to the specified character.
57     void advance(unsigned to, GlyphBuffer* = 0, GlyphIterationStyle = IncludePartialGlyphs, HashSet<const SimpleFontData*>* fallbackFonts = 0);
58 
59     // Compute the character offset for a given x coordinate.
60     int offsetForPosition(float x, bool includePartialGlyphs);
61 
62     // Returns the width of everything we've consumed so far.
runWidthSoFar()63     float runWidthSoFar() const { return m_runWidthSoFar; }
64 
totalWidth()65     float totalWidth() const { return m_totalWidth; }
66 
finalRoundingWidth()67     float finalRoundingWidth() const { return m_finalRoundingWidth; }
68 
minGlyphBoundingBoxX()69     float minGlyphBoundingBoxX() const { return m_minGlyphBoundingBoxX; }
maxGlyphBoundingBoxX()70     float maxGlyphBoundingBoxX() const { return m_maxGlyphBoundingBoxX; }
minGlyphBoundingBoxY()71     float minGlyphBoundingBoxY() const { return m_minGlyphBoundingBoxY; }
maxGlyphBoundingBoxY()72     float maxGlyphBoundingBoxY() const { return m_maxGlyphBoundingBoxY; }
73 
74 private:
75     class ComplexTextRun : public RefCounted<ComplexTextRun> {
76     public:
create(CTRunRef ctRun,const SimpleFontData * fontData,const UChar * characters,unsigned stringLocation,size_t stringLength,CFRange runRange)77         static PassRefPtr<ComplexTextRun> create(CTRunRef ctRun, const SimpleFontData* fontData, const UChar* characters, unsigned stringLocation, size_t stringLength, CFRange runRange)
78         {
79             return adoptRef(new ComplexTextRun(ctRun, fontData, characters, stringLocation, stringLength, runRange));
80         }
81 
create(const SimpleFontData * fontData,const UChar * characters,unsigned stringLocation,size_t stringLength,bool ltr)82         static PassRefPtr<ComplexTextRun> create(const SimpleFontData* fontData, const UChar* characters, unsigned stringLocation, size_t stringLength, bool ltr)
83         {
84             return adoptRef(new ComplexTextRun(fontData, characters, stringLocation, stringLength, ltr));
85         }
86 
glyphCount()87         unsigned glyphCount() const { return m_glyphCount; }
fontData()88         const SimpleFontData* fontData() const { return m_fontData; }
characters()89         const UChar* characters() const { return m_characters; }
stringLocation()90         unsigned stringLocation() const { return m_stringLocation; }
stringLength()91         size_t stringLength() const { return m_stringLength; }
92         ALWAYS_INLINE CFIndex indexAt(size_t i) const;
indexBegin()93         CFIndex indexBegin() const { return m_indexBegin; }
indexEnd()94         CFIndex indexEnd() const { return m_indexEnd; }
endOffsetAt(size_t i)95         CFIndex endOffsetAt(size_t i) const { ASSERT(!m_isMonotonic); return m_glyphEndOffsets[i]; }
glyphs()96         const CGGlyph* glyphs() const { return m_glyphs; }
advances()97         const CGSize* advances() const { return m_advances; }
isLTR()98         bool isLTR() const { return m_isLTR; }
isMonotonic()99         bool isMonotonic() const { return m_isMonotonic; }
100         void setIsNonMonotonic();
101 
102     private:
103         ComplexTextRun(CTRunRef, const SimpleFontData*, const UChar* characters, unsigned stringLocation, size_t stringLength, CFRange runRange);
104         ComplexTextRun(const SimpleFontData*, const UChar* characters, unsigned stringLocation, size_t stringLength, bool ltr);
105 
106         unsigned m_glyphCount;
107         const SimpleFontData* m_fontData;
108         const UChar* m_characters;
109         unsigned m_stringLocation;
110         size_t m_stringLength;
111         Vector<CFIndex, 64> m_coreTextIndicesVector;
112         const CFIndex* m_coreTextIndices;
113         CFIndex m_indexBegin;
114         CFIndex m_indexEnd;
115         Vector<CFIndex, 64> m_glyphEndOffsets;
116         Vector<CGGlyph, 64> m_glyphsVector;
117         const CGGlyph* m_glyphs;
118         Vector<CGSize, 64> m_advancesVector;
119         const CGSize* m_advances;
120         bool m_isLTR;
121         bool m_isMonotonic;
122     };
123 
stringBegin(const ComplexTextRun & run)124     static unsigned stringBegin(const ComplexTextRun& run) { return run.stringLocation() + run.indexBegin(); }
stringEnd(const ComplexTextRun & run)125     static unsigned stringEnd(const ComplexTextRun& run) { return run.stringLocation() + run.indexEnd(); }
126 
127     void collectComplexTextRuns();
128 
129     void collectComplexTextRunsForCharacters(const UChar*, unsigned length, unsigned stringLocation, const SimpleFontData*);
130     void adjustGlyphsAndAdvances();
131 
132     unsigned findNextRunIndex(unsigned runIndex) const;
133     unsigned indexOfCurrentRun(unsigned& leftmostGlyph);
134     unsigned incrementCurrentRun(unsigned& leftmostGlyph);
135 
136     // The initial capacity of these vectors was selected as being the smallest power of two greater than
137     // the average (3.5) plus one standard deviation (7.5) of nonzero sizes used on Arabic Wikipedia.
138     Vector<unsigned, 16> m_runIndices;
139     Vector<unsigned, 16> m_glyphCountFromStartToIndex;
140 
141     const Font& m_font;
142     const TextRun& m_run;
143     bool m_isLTROnly;
144     bool m_mayUseNaturalWritingDirection;
145     bool m_forTextEmphasis;
146 
147     Vector<String> m_stringsFor8BitRuns;
148     Vector<UChar, 256> m_smallCapsBuffer;
149 
150     // Retain lines rather than their runs for better performance.
151     Vector<RetainPtr<CTLineRef> > m_coreTextLines;
152     Vector<RefPtr<ComplexTextRun>, 16> m_complexTextRuns;
153     Vector<CGSize, 256> m_adjustedAdvances;
154     Vector<CGGlyph, 256> m_adjustedGlyphs;
155 
156     unsigned m_currentCharacter;
157     int m_end;
158 
159     CGFloat m_totalWidth;
160 
161     float m_runWidthSoFar;
162     unsigned m_numGlyphsSoFar;
163     size_t m_currentRun;
164     unsigned m_glyphInCurrentRun;
165     unsigned m_characterInCurrentGlyph;
166     float m_finalRoundingWidth;
167     float m_expansion;
168     float m_expansionPerOpportunity;
169     float m_leadingExpansion;
170     bool m_afterExpansion;
171 
172     HashSet<const SimpleFontData*>* m_fallbackFonts;
173 
174     float m_minGlyphBoundingBoxX;
175     float m_maxGlyphBoundingBoxX;
176     float m_minGlyphBoundingBoxY;
177     float m_maxGlyphBoundingBoxY;
178 
179     unsigned m_lastRoundingGlyph;
180 };
181 
182 } // namespace WebCore
183 
184 #endif // ComplexTextController_h
185