1/*
2 * Copyright (C) 2012 Google 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 are
6 * met:
7 *
8 *     * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *     * Redistributions in binary form must reproduce the above
11 * copyright notice, this list of conditions and the following disclaimer
12 * in the documentation and/or other materials provided with the
13 * distribution.
14 *     * Neither the name of Google Inc. nor the names of its
15 * contributors may be used to endorse or promote products derived from
16 * this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#ifndef HarfBuzzShaper_h
32#define HarfBuzzShaper_h
33
34#include "hb.h"
35#include "platform/geometry/FloatBoxExtent.h"
36#include "platform/geometry/FloatPoint.h"
37#include "platform/text/TextRun.h"
38#include "wtf/HashSet.h"
39#include "wtf/OwnPtr.h"
40#include "wtf/PassOwnPtr.h"
41#include "wtf/unicode/CharacterNames.h"
42#include "wtf/Vector.h"
43
44#include <unicode/uscript.h>
45
46namespace blink {
47
48class Font;
49class GlyphBuffer;
50class SimpleFontData;
51
52class HarfBuzzShaper FINAL {
53public:
54    enum ForTextEmphasisOrNot {
55        NotForTextEmphasis,
56        ForTextEmphasis
57    };
58
59    HarfBuzzShaper(const Font*, const TextRun&, ForTextEmphasisOrNot = NotForTextEmphasis, HashSet<const SimpleFontData*>* fallbackFonts = 0);
60
61    void setDrawRange(int from, int to);
62    bool shape(GlyphBuffer* = 0);
63    FloatPoint adjustStartPoint(const FloatPoint&);
64    float totalWidth() { return m_totalWidth; }
65    int offsetForPosition(float targetX);
66    FloatRect selectionRect(const FloatPoint&, int height, int from, int to);
67    FloatBoxExtent glyphBoundingBox() const { return m_glyphBoundingBox; }
68
69private:
70    class HarfBuzzRun {
71    public:
72        HarfBuzzRun(const HarfBuzzRun&);
73        ~HarfBuzzRun();
74
75        static PassOwnPtr<HarfBuzzRun> create(const SimpleFontData* fontData, unsigned startIndex, unsigned numCharacters, hb_direction_t direction, hb_script_t script)
76        {
77            return adoptPtr(new HarfBuzzRun(fontData, startIndex, numCharacters, direction, script));
78        }
79
80        void applyShapeResult(hb_buffer_t*);
81        void setGlyphAndPositions(unsigned index, uint16_t glyphId, float advance, float offsetX, float offsetY);
82        void setWidth(float width) { m_width = width; }
83
84        int characterIndexForXPosition(float targetX);
85        float xPositionForOffset(unsigned offset);
86
87        const SimpleFontData* fontData() { return m_fontData; }
88        unsigned startIndex() const { return m_startIndex; }
89        unsigned numCharacters() const { return m_numCharacters; }
90        unsigned numGlyphs() const { return m_numGlyphs; }
91        uint16_t* glyphs() { return &m_glyphs[0]; }
92        float* advances() { return &m_advances[0]; }
93        FloatPoint* offsets() { return &m_offsets[0]; }
94        bool hasGlyphToCharacterIndexes() const
95        {
96            return m_glyphToCharacterIndexes.size() > 0;
97        }
98        uint16_t* glyphToCharacterIndexes()
99        {
100            return &m_glyphToCharacterIndexes[0];
101        }
102        float width() { return m_width; }
103        hb_direction_t direction() { return m_direction; }
104        bool rtl() { return m_direction == HB_DIRECTION_RTL; }
105        hb_script_t script() { return m_script; }
106
107    private:
108        HarfBuzzRun(const SimpleFontData*, unsigned startIndex, unsigned numCharacters, hb_direction_t, hb_script_t);
109
110        const SimpleFontData* m_fontData;
111        unsigned m_startIndex;
112        size_t m_numCharacters;
113        unsigned m_numGlyphs;
114        hb_direction_t m_direction;
115        hb_script_t m_script;
116        Vector<uint16_t, 256> m_glyphs;
117        Vector<float, 256> m_advances;
118        Vector<uint16_t, 256> m_glyphToCharacterIndexes;
119        Vector<FloatPoint, 256> m_offsets;
120        float m_width;
121    };
122
123    int determineWordBreakSpacing();
124    // setPadding sets a number of pixels to be distributed across the TextRun.
125    // WebKit uses this to justify text.
126    void setPadding(int);
127
128    void setFontFeatures();
129
130    bool createHarfBuzzRuns();
131    bool shapeHarfBuzzRuns();
132    bool fillGlyphBuffer(GlyphBuffer*);
133    void fillGlyphBufferFromHarfBuzzRun(GlyphBuffer*, HarfBuzzRun*, FloatPoint& firstOffsetOfNextRun);
134    void fillGlyphBufferForTextEmphasis(GlyphBuffer*, HarfBuzzRun* currentRun);
135    void setGlyphPositionsForHarfBuzzRun(HarfBuzzRun*, hb_buffer_t*);
136    void addHarfBuzzRun(unsigned startCharacter, unsigned endCharacter, const SimpleFontData*, UScriptCode);
137
138    const Font* m_font;
139    OwnPtr<UChar[]> m_normalizedBuffer;
140    unsigned m_normalizedBufferLength;
141    const TextRun& m_run;
142
143    float m_wordSpacingAdjustment; // Delta adjustment (pixels) for each word break.
144    float m_padding; // Pixels to be distributed over the line at word breaks.
145    float m_padPerWordBreak; // Pixels to be added to each word break.
146    float m_padError; // m_padPerWordBreak might have a fractional component. Since we only add a whole number of padding pixels at each word break we accumulate error. This is the number of pixels that we are behind so far.
147    float m_letterSpacing; // Pixels to be added after each glyph.
148
149    Vector<hb_feature_t, 4> m_features;
150    Vector<OwnPtr<HarfBuzzRun>, 16> m_harfBuzzRuns;
151
152    FloatPoint m_startOffset;
153
154    int m_fromIndex;
155    int m_toIndex;
156
157    ForTextEmphasisOrNot m_forTextEmphasis;
158
159    float m_totalWidth;
160    FloatBoxExtent m_glyphBoundingBox;
161    HashSet<const SimpleFontData*>* m_fallbackFonts;
162
163    friend struct CachedShapingResults;
164};
165
166} // namespace blink
167
168#endif // HarfBuzzShaper_h
169