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1 /*
2  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
3  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
4  *           (C) 2000 Dirk Mueller (mueller@kde.org)
5  * Copyright (C) 2003, 2006, 2007 Apple Computer, Inc.
6  * Copyright (C) 2008 Holger Hans Peter Freyther
7  *
8  * This library is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Library General Public
10  * License as published by the Free Software Foundation; either
11  * version 2 of the License, or (at your option) any later version.
12  *
13  * This library is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16  * Library General Public License for more details.
17  *
18  * You should have received a copy of the GNU Library General Public License
19  * along with this library; see the file COPYING.LIB.  If not, write to
20  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
21  * Boston, MA 02110-1301, USA.
22  *
23  */
24 
25 #ifndef Font_h
26 #define Font_h
27 
28 #include "CharacterNames.h"
29 #include "TextRun.h"
30 #include "FontDescription.h"
31 #include "SimpleFontData.h"
32 #include "TypesettingFeatures.h"
33 #include <wtf/HashMap.h>
34 #include <wtf/HashSet.h>
35 #include <wtf/MathExtras.h>
36 
37 #if PLATFORM(QT)
38 #include <QFont>
39 #endif
40 
41 namespace WebCore {
42 
43 class FloatPoint;
44 class FloatRect;
45 class FontData;
46 class FontFallbackList;
47 class FontPlatformData;
48 class FontSelector;
49 class GlyphBuffer;
50 class GlyphPageTreeNode;
51 class GraphicsContext;
52 class IntPoint;
53 class SVGFontElement;
54 
55 struct GlyphData;
56 
57 const unsigned defaultUnitsPerEm = 1000;
58 
59 class Font {
60 public:
61     Font();
62     Font(const FontDescription&, short letterSpacing, short wordSpacing);
63     // This constructor is only used if the platform wants to start with a native font.
64     Font(const FontPlatformData&, bool isPrinting);
65     ~Font();
66 
67     Font(const Font&);
68     Font& operator=(const Font&);
69 
70     bool operator==(const Font& other) const;
71     bool operator!=(const Font& other) const {
72         return !(*this == other);
73     }
74 
fontDescription()75     const FontDescription& fontDescription() const { return m_fontDescription; }
76 
pixelSize()77     int pixelSize() const { return fontDescription().computedPixelSize(); }
size()78     float size() const { return fontDescription().computedSize(); }
79 
80     void update(PassRefPtr<FontSelector>) const;
81 
82     void drawText(GraphicsContext*, const TextRun&, const FloatPoint&, int from = 0, int to = -1) const;
83 
84     int width(const TextRun& run, HashSet<const SimpleFontData*>* fallbackFonts = 0) const { return lroundf(floatWidth(run, fallbackFonts)); }
85     float floatWidth(const TextRun&, HashSet<const SimpleFontData*>* fallbackFonts = 0) const;
86     float floatWidth(const TextRun& run, int extraCharsAvailable, int& charsConsumed, String& glyphName) const;
87 
88     int offsetForPosition(const TextRun&, int position, bool includePartialGlyphs) const;
89     FloatRect selectionRectForText(const TextRun&, const IntPoint&, int h, int from = 0, int to = -1) const;
90 
isSmallCaps()91     bool isSmallCaps() const { return m_fontDescription.smallCaps(); }
92 
wordSpacing()93     short wordSpacing() const { return m_wordSpacing; }
letterSpacing()94     short letterSpacing() const { return m_letterSpacing; }
setWordSpacing(short s)95     void setWordSpacing(short s) { m_wordSpacing = s; }
setLetterSpacing(short s)96     void setLetterSpacing(short s) { m_letterSpacing = s; }
97     bool isFixedPitch() const;
isPrinterFont()98     bool isPrinterFont() const { return m_fontDescription.usePrinterFont(); }
99 
renderingMode()100     FontRenderingMode renderingMode() const { return m_fontDescription.renderingMode(); }
101 
typesettingFeatures()102     TypesettingFeatures typesettingFeatures() const
103     {
104         TextRenderingMode textRenderingMode = m_fontDescription.textRenderingMode();
105         return textRenderingMode == OptimizeLegibility || textRenderingMode == GeometricPrecision ? Kerning | Ligatures : 0;
106     }
107 
firstFamily()108     FontFamily& firstFamily() { return m_fontDescription.firstFamily(); }
family()109     const FontFamily& family() const { return m_fontDescription.family(); }
110 
italic()111     bool italic() const { return m_fontDescription.italic(); }
weight()112     FontWeight weight() const { return m_fontDescription.weight(); }
113 
isPlatformFont()114     bool isPlatformFont() const { return m_isPlatformFont; }
115 
116     // Metrics that we query the FontFallbackList for.
ascent()117     int ascent() const { return primaryFont()->ascent(); }
descent()118     int descent() const { return primaryFont()->descent(); }
height()119     int height() const { return ascent() + descent(); }
lineSpacing()120     int lineSpacing() const { return primaryFont()->lineSpacing(); }
lineGap()121     int lineGap() const { return primaryFont()->lineGap(); }
xHeight()122     float xHeight() const { return primaryFont()->xHeight(); }
unitsPerEm()123     unsigned unitsPerEm() const { return primaryFont()->unitsPerEm(); }
spaceWidth()124     int spaceWidth() const { return (int)ceilf(primaryFont()->adjustedSpaceWidth() + m_letterSpacing); }
tabWidth()125     int tabWidth() const { return 8 * spaceWidth(); }
126 
127     const SimpleFontData* primaryFont() const;
128     const FontData* fontDataAt(unsigned) const;
129     GlyphData glyphDataForCharacter(UChar32, bool mirror, bool forceSmallCaps = false) const;
130     // Used for complex text, and does not utilize the glyph map cache.
131     const FontData* fontDataForCharacters(const UChar*, int length) const;
132 
133 #if PLATFORM(QT)
134     QFont font() const;
135 #endif
136 
137     static void setShouldUseSmoothing(bool);
138     static bool shouldUseSmoothing();
139 
140 private:
141 #if ENABLE(SVG_FONTS)
142     void drawTextUsingSVGFont(GraphicsContext*, const TextRun&, const FloatPoint&, int from, int to) const;
143     float floatWidthUsingSVGFont(const TextRun&) const;
144     float floatWidthUsingSVGFont(const TextRun&, int extraCharsAvailable, int& charsConsumed, String& glyphName) const;
145     FloatRect selectionRectForTextUsingSVGFont(const TextRun&, const IntPoint&, int h, int from, int to) const;
146     int offsetForPositionForTextUsingSVGFont(const TextRun&, int position, bool includePartialGlyphs) const;
147 #endif
148 
149 #if USE(FONT_FAST_PATH)
150     bool canUseGlyphCache(const TextRun&) const;
151     void drawSimpleText(GraphicsContext*, const TextRun&, const FloatPoint&, int from, int to) const;
152     void drawGlyphs(GraphicsContext*, const SimpleFontData*, const GlyphBuffer&, int from, int to, const FloatPoint&) const;
153     void drawGlyphBuffer(GraphicsContext*, const GlyphBuffer&, const TextRun&, const FloatPoint&) const;
154     float floatWidthForSimpleText(const TextRun&, GlyphBuffer*, HashSet<const SimpleFontData*>* fallbackFonts = 0) const;
155     int offsetForPositionForSimpleText(const TextRun&, int position, bool includePartialGlyphs) const;
156     FloatRect selectionRectForSimpleText(const TextRun&, const IntPoint&, int h, int from, int to) const;
157 
158     static bool canReturnFallbackFontsForComplexText();
159 #endif
160 
161     void drawComplexText(GraphicsContext*, const TextRun&, const FloatPoint&, int from, int to) const;
162     float floatWidthForComplexText(const TextRun&, HashSet<const SimpleFontData*>* fallbackFonts = 0) const;
163     int offsetForPositionForComplexText(const TextRun&, int position, bool includePartialGlyphs) const;
164     FloatRect selectionRectForComplexText(const TextRun&, const IntPoint&, int h, int from, int to) const;
165 
166     friend struct WidthIterator;
167 
168 public:
169     // Useful for debugging the different font rendering code paths.
170 #if USE(FONT_FAST_PATH)
171     enum CodePath { Auto, Simple, Complex };
172     static void setCodePath(CodePath);
173     static CodePath codePath();
174     static CodePath s_codePath;
175 
176     static const uint8_t gRoundingHackCharacterTable[256];
isRoundingHackCharacter(UChar32 c)177     static bool isRoundingHackCharacter(UChar32 c)
178     {
179         return (((c & ~0xFF) == 0 && gRoundingHackCharacterTable[c]));
180     }
181 #endif
182 
183     FontSelector* fontSelector() const;
treatAsSpace(UChar c)184     static bool treatAsSpace(UChar c) { return c == ' ' || c == '\t' || c == '\n' || c == 0x00A0; }
treatAsZeroWidthSpace(UChar c)185     static bool treatAsZeroWidthSpace(UChar c) { return c < 0x20 || (c >= 0x7F && c < 0xA0) || c == 0x200e || c == 0x200f || (c >= 0x202a && c <= 0x202e) || c == 0xFFFC; }
186 
normalizeSpaces(UChar character)187     static inline UChar normalizeSpaces(UChar character)
188     {
189         if (treatAsSpace(character))
190             return space;
191 
192         if (treatAsZeroWidthSpace(character))
193             return zeroWidthSpace;
194 
195         return character;
196     }
197 
198     static String normalizeSpaces(const String&);
199 
200 #if ENABLE(SVG_FONTS)
201     bool isSVGFont() const;
202     SVGFontElement* svgFont() const;
203 #endif
204 
205 private:
206     FontDescription m_fontDescription;
207     mutable RefPtr<FontFallbackList> m_fontList;
208     short m_letterSpacing;
209     short m_wordSpacing;
210     bool m_isPlatformFont;
211 };
212 
213 }
214 
215 #endif
216