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 "core/platform/graphics/FloatPoint.h"
35#include "core/platform/graphics/GlyphBuffer.h"
36#include "core/platform/graphics/TextRun.h"
37#include "hb.h"
38#include "wtf/HashSet.h"
39#include "wtf/OwnArrayPtr.h"
40#include "wtf/OwnPtr.h"
41#include "wtf/PassOwnPtr.h"
42#include "wtf/unicode/CharacterNames.h"
43#include "wtf/Vector.h"
44
45namespace WebCore {
46
47class Font;
48class SimpleFontData;
49
50class HarfBuzzShaper {
51public:
52    enum NormalizeMode {
53        DoNotNormalizeMirrorChars,
54        NormalizeMirrorChars
55    };
56
57    HarfBuzzShaper(const Font*, const TextRun&);
58    virtual ~HarfBuzzShaper();
59
60    void setDrawRange(int from, int to);
61    bool shape(GlyphBuffer* = 0);
62    FloatPoint adjustStartPoint(const FloatPoint&);
63    float totalWidth() { return m_totalWidth; }
64    int offsetForPosition(float targetX);
65    FloatRect selectionRect(const FloatPoint&, int height, int from, int to);
66
67private:
68    class HarfBuzzRun {
69    public:
70        static PassOwnPtr<HarfBuzzRun> create(const SimpleFontData* fontData, unsigned startIndex, unsigned numCharacters, TextDirection direction, hb_script_t script)
71        {
72            return adoptPtr(new HarfBuzzRun(fontData, startIndex, numCharacters, direction, script));
73        }
74
75        void applyShapeResult(hb_buffer_t*);
76        void setGlyphAndPositions(unsigned index, uint16_t glyphId, float advance, float offsetX, float offsetY);
77        void setWidth(float width) { m_width = width; }
78
79        int characterIndexForXPosition(float targetX);
80        float xPositionForOffset(unsigned offset);
81
82        const SimpleFontData* fontData() { return m_fontData; }
83        unsigned startIndex() const { return m_startIndex; }
84        unsigned numCharacters() const { return m_numCharacters; }
85        unsigned numGlyphs() const { return m_numGlyphs; }
86        uint16_t* glyphs() { return &m_glyphs[0]; }
87        float* advances() { return &m_advances[0]; }
88        FloatPoint* offsets() { return &m_offsets[0]; }
89        uint16_t* glyphToCharacterIndexes() { return &m_glyphToCharacterIndexes[0]; }
90        float width() { return m_width; }
91        bool rtl() { return m_direction == RTL; }
92        hb_script_t script() { return m_script; }
93
94    private:
95        HarfBuzzRun(const SimpleFontData*, unsigned startIndex, unsigned numCharacters, TextDirection, hb_script_t);
96
97        const SimpleFontData* m_fontData;
98        unsigned m_startIndex;
99        size_t m_numCharacters;
100        unsigned m_numGlyphs;
101        TextDirection m_direction;
102        hb_script_t m_script;
103        Vector<uint16_t, 256> m_glyphs;
104        Vector<float, 256> m_advances;
105        Vector<uint16_t, 256> m_glyphToCharacterIndexes;
106        Vector<FloatPoint, 256> m_offsets;
107        float m_width;
108    };
109
110    void setNormalizedBuffer(NormalizeMode = DoNotNormalizeMirrorChars);
111
112    bool isWordEnd(unsigned);
113    int determineWordBreakSpacing();
114    // setPadding sets a number of pixels to be distributed across the TextRun.
115    // WebKit uses this to justify text.
116    void setPadding(int);
117
118    // In complex text word-spacing affects each line-break, space (U+0020) and non-breaking space (U+00A0).
119    static bool isCodepointSpace(UChar c) { return c == ' ' || c == noBreakSpace || c == '\n'; }
120
121    void setFontFeatures();
122
123    bool collectHarfBuzzRuns();
124    bool shapeHarfBuzzRuns(bool shouldSetDirection);
125    bool fillGlyphBuffer(GlyphBuffer*);
126    void fillGlyphBufferFromHarfBuzzRun(GlyphBuffer*, HarfBuzzRun*, FloatPoint& firstOffsetOfNextRun);
127    void setGlyphPositionsForHarfBuzzRun(HarfBuzzRun*, hb_buffer_t*);
128
129    GlyphBufferAdvance createGlyphBufferAdvance(float, float);
130
131    const Font* m_font;
132    OwnArrayPtr<UChar> m_normalizedBuffer;
133    unsigned m_normalizedBufferLength;
134    const TextRun& m_run;
135
136    int m_wordSpacingAdjustment; // Delta adjustment (pixels) for each word break.
137    float m_padding; // Pixels to be distributed over the line at word breaks.
138    float m_padPerWordBreak; // Pixels to be added to each word break.
139    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.
140    int m_letterSpacing; // Pixels to be added after each glyph.
141
142    Vector<hb_feature_t, 4> m_features;
143    Vector<OwnPtr<HarfBuzzRun>, 16> m_harfBuzzRuns;
144
145    FloatPoint m_startOffset;
146
147    int m_fromIndex;
148    int m_toIndex;
149
150    float m_totalWidth;
151};
152
153} // namespace WebCore
154
155#endif // HarfBuzzShaper_h
156