third_party/WebKit/Source/platform/fonts/Font.h

   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, 2010, 2011 Apple Inc. All rights reserved.
   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 "platform/LayoutUnit.h"
  29 #include "platform/PlatformExport.h"
  30 #include "platform/fonts/FontDescription.h"
  31 #include "platform/fonts/FontFallbackList.h"
  32 #include "platform/fonts/SimpleFontData.h"
  33 #include "platform/fonts/TextBlob.h"
  34 #include "platform/text/TabSize.h"
  35 #include "platform/text/TextDirection.h"
  36 #include "platform/text/TextPath.h"
  37 #include "wtf/HashMap.h"
  38 #include "wtf/HashSet.h"
  39 #include "wtf/MathExtras.h"
  40 #include "wtf/text/CharacterNames.h"
  41
  42 class SkCanvas;
  43 class SkPaint;
  44 class SkTextBlob;
  45 struct SkPoint;
  46
  47 namespace blink {
  48
  49 class FloatPoint;
  50 class FloatRect;
  51 class FontData;
  52 class FontMetrics;
  53 class FontSelector;
  54 class GlyphBuffer;
  55 class TextRun;
  56 struct TextRunPaintInfo;
  57
  58 struct GlyphData;
  59
  60 class PLATFORM_EXPORT Font {
  61 public:
  62     Font();
  63     Font(const FontDescription&);
  64     ~Font();
  65
  66     Font(const Font&);
  67     Font& operator=(const Font&);
  68
  69     bool operator==(const Font& other) const;
  70     bool operator!=(const Font& other) const { return !(*this == other); }
  71
  72     const FontDescription& fontDescription() const { return m_fontDescription; }
  73
  74     void update(PassRefPtrWillBeRawPtr<FontSelector>) const;
  75
  76     enum CustomFontNotReadyAction { DoNotPaintIfFontNotReady, UseFallbackIfFontNotReady };
  77     void drawText(SkCanvas*, const TextRunPaintInfo&, const FloatPoint&, float deviceScaleFactor, const SkPaint&) const;
  78     void drawBidiText(SkCanvas*, const TextRunPaintInfo&, const FloatPoint&, CustomFontNotReadyAction, float deviceScaleFactor, const SkPaint&) const;
  79     void drawEmphasisMarks(SkCanvas*, const TextRunPaintInfo&, const AtomicString& mark, const FloatPoint&, float deviceScaleFactor, const SkPaint&) const;
  80
  81     // Glyph bounds will be the minimum rect containing all glyph strokes, in coordinates using
  82     // (<text run x position>, <baseline position>) as the origin.
  83     float width(const TextRun&, HashSet<const SimpleFontData*>* fallbackFonts = nullptr, FloatRect* glyphBounds = nullptr) const;
  84
  85     int offsetForPosition(const TextRun&, float position, bool includePartialGlyphs) const;
  86     FloatRect selectionRectForText(const TextRun&, const FloatPoint&, int h, int from = 0, int to = -1, bool accountForGlyphBounds = false) const;
  87
  88     // Metrics that we query the FontFallbackList for.
  89     const FontMetrics& fontMetrics() const { return primaryFont()->fontMetrics(); }
  90     float spaceWidth() const { return primaryFont()->spaceWidth() + fontDescription().letterSpacing(); }
  91     float tabWidth(const SimpleFontData&, const TabSize&, float position) const;
  92     float tabWidth(const TabSize& tabSize, float position) const { return tabWidth(*primaryFont(), tabSize, position); }
  93
  94     int emphasisMarkAscent(const AtomicString&) const;
  95     int emphasisMarkDescent(const AtomicString&) const;
  96     int emphasisMarkHeight(const AtomicString&) const;
  97
  98     const SimpleFontData* primaryFont() const;
  99     const FontData* fontDataAt(unsigned) const;
 100
 101     GlyphData glyphDataForCharacter(UChar32&, bool mirror, bool normalizeSpace = false, FontDataVariant = AutoVariant) const;
 102     CodePath codePath(const TextRunPaintInfo&) const;
 103
 104     // Whether the font supports shaping word by word instead of shaping the
 105     // full run in one go. Allows better caching for fonts where space cannot
 106     // participate in kerning and/or ligatures.
 107     bool canShapeWordByWord() const;
 108
 109     void setCanShapeWordByWordForTesting(bool b)
 110     {
 111         m_canShapeWordByWord = b;
 112         m_shapeWordByWordComputed = true;
 113     }
 114
 115 private:
 116     enum ForTextEmphasisOrNot { NotForTextEmphasis, ForTextEmphasis };
 117
 118     // Returns the total advance.
 119     float buildGlyphBuffer(const TextRunPaintInfo&, GlyphBuffer&, const GlyphData* emphasisData = nullptr) const;
 120     PassTextBlobPtr buildTextBlob(const GlyphBuffer&) const;
 121     void paintGlyphs(SkCanvas*, const SkPaint&, const SimpleFontData*, const Glyph glyphs[], unsigned numGlyphs,
 122         const SkPoint pos[], const FloatRect& textRect, float deviceScaleFactor) const;
 123     void paintGlyphsHorizontal(SkCanvas*, const SkPaint&, const SimpleFontData*, const Glyph glyphs[], unsigned numGlyphs,
 124         const SkScalar xpos[], SkScalar constY, const FloatRect& textRect, float deviceScaleFactor) const;
 125     void drawGlyphs(SkCanvas*, const SkPaint&, const SimpleFontData*, const GlyphBuffer&, unsigned from, unsigned numGlyphs,
 126         const FloatPoint&, const FloatRect& textRect, float deviceScaleFactor) const;
 127     void drawTextBlob(SkCanvas*, const SkPaint&, const SkTextBlob*, const SkPoint& origin) const;
 128     void drawGlyphBuffer(SkCanvas*, const SkPaint&, const TextRunPaintInfo&, const GlyphBuffer&, const FloatPoint&, float deviceScaleFactor) const;
 129     float floatWidthForSimpleText(const TextRun&, HashSet<const SimpleFontData*>* fallbackFonts = 0, FloatRect* glyphBounds = 0) const;
 130     int offsetForPositionForSimpleText(const TextRun&, float position, bool includePartialGlyphs) const;
 131     FloatRect selectionRectForSimpleText(const TextRun&, const FloatPoint&, int h, int from, int to, bool accountForGlyphBounds) const;
 132
 133     bool getEmphasisMarkGlyphData(const AtomicString&, GlyphData&) const;
 134
 135     float floatWidthForComplexText(const TextRun&, HashSet<const SimpleFontData*>* fallbackFonts, FloatRect* glyphBounds) const;
 136     int offsetForPositionForComplexText(const TextRun&, float position, bool includePartialGlyphs) const;
 137     FloatRect selectionRectForComplexText(const TextRun&, const FloatPoint&, int h, int from, int to) const;
 138
 139     bool computeCanShapeWordByWord() const;
 140
 141     friend struct SimpleShaper;
 142
 143 public:
 144     FontSelector* fontSelector() const;
 145
 146     void willUseFontData(UChar32) const;
 147
 148     bool loadingCustomFonts() const;
 149     bool isFallbackValid() const;
 150
 151 private:
 152     bool shouldSkipDrawing() const
 153     {
 154         return m_fontFallbackList && m_fontFallbackList->shouldSkipDrawing();
 155     }
 156
 157     FontDescription m_fontDescription;
 158     mutable RefPtr<FontFallbackList> m_fontFallbackList;
 159     mutable unsigned m_canShapeWordByWord : 1;
 160     mutable unsigned m_shapeWordByWordComputed : 1;
 161 };
 162
 163 inline Font::~Font()
 164 {
 165 }
 166
 167 inline const SimpleFontData* Font::primaryFont() const
 168 {
 169     ASSERT(m_fontFallbackList);
 170     return m_fontFallbackList->primarySimpleFontData(m_fontDescription);
 171 }
 172
 173 inline const FontData* Font::fontDataAt(unsigned index) const
 174 {
 175     ASSERT(m_fontFallbackList);
 176     return m_fontFallbackList->fontDataAt(m_fontDescription, index);
 177 }
 178
 179 inline FontSelector* Font::fontSelector() const
 180 {
 181     return m_fontFallbackList ? m_fontFallbackList->fontSelector() : 0;
 182 }
 183
 184 inline float Font::tabWidth(const SimpleFontData& fontData, const TabSize& tabSize, float position) const
 185 {
 186     float baseTabWidth = tabSize.getPixelSize(fontData.spaceWidth());
 187     if (!baseTabWidth)
 188         return fontDescription().letterSpacing();
 189     float distanceToTabStop = baseTabWidth - fmodf(position, baseTabWidth);
 190
 191     // The smallest allowable tab space is letterSpacing() (but must be at least one layout unit).
 192     // if the distance to the next tab stop is less than that, advance an additional tab stop.
 193     if (distanceToTabStop < std::max(fontDescription().letterSpacing(), LayoutUnit::epsilon()))
 194         distanceToTabStop += baseTabWidth;
 195
 196     return distanceToTabStop;
 197 }
 198
 199 } // namespace blink
 200
 201 #endif