1 /* 2 * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved. 3 * 4 * This library is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU Library General Public 6 * License as published by the Free Software Foundation; either 7 * version 2 of the License, or (at your option) any later version. 8 * 9 * This library is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 * Library General Public License for more details. 13 * 14 * You should have received a copy of the GNU Library General Public License 15 * along with this library; see the file COPYING.LIB. If not, write to 16 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, 17 * Boston, MA 02110-1301, USA. 18 */ 19 20 #ifndef FontMetrics_h 21 #define FontMetrics_h 22 23 #include "platform/fonts/FontBaseline.h" 24 #include "wtf/MathExtras.h" 25 26 namespace blink { 27 28 const unsigned gDefaultUnitsPerEm = 1000; 29 30 class FontMetrics { 31 public: 32 FontMetrics() 33 : m_unitsPerEm(gDefaultUnitsPerEm) 34 , m_ascent(0) 35 , m_descent(0) 36 , m_lineGap(0) 37 , m_lineSpacing(0) 38 , m_xHeight(0) 39 , m_zeroWidth(0) 40 , m_underlinethickness(0) 41 , m_underlinePosition(0) 42 , m_hasXHeight(false) 43 , m_hasZeroWidth(false) 44 { 45 } 46 47 unsigned unitsPerEm() const { return m_unitsPerEm; } 48 void setUnitsPerEm(unsigned unitsPerEm) { m_unitsPerEm = unitsPerEm; } 49 50 float floatAscent(FontBaseline baselineType = AlphabeticBaseline) const 51 { 52 if (baselineType == AlphabeticBaseline) 53 return m_ascent; 54 return floatHeight() / 2; 55 } 56 57 void setAscent(float ascent) { m_ascent = ascent; } 58 59 float floatDescent(FontBaseline baselineType = AlphabeticBaseline) const 60 { 61 if (baselineType == AlphabeticBaseline) 62 return m_descent; 63 return floatHeight() / 2; 64 } 65 66 void setDescent(float descent) { m_descent = descent; } 67 68 float floatHeight(FontBaseline baselineType = AlphabeticBaseline) const 69 { 70 return floatAscent(baselineType) + floatDescent(baselineType); 71 } 72 73 float floatLineGap() const { return m_lineGap; } 74 void setLineGap(float lineGap) { m_lineGap = lineGap; } 75 76 float floatLineSpacing() const { return m_lineSpacing; } 77 void setLineSpacing(float lineSpacing) { m_lineSpacing = lineSpacing; } 78 79 float xHeight() const { return m_xHeight; } 80 void setXHeight(float xHeight) 81 { 82 m_xHeight = xHeight; 83 m_hasXHeight = true; 84 } 85 86 bool hasXHeight() const { return m_hasXHeight && m_xHeight > 0; } 87 void setHasXHeight(bool hasXHeight) { m_hasXHeight = hasXHeight; } 88 89 // Integer variants of certain metrics, used for HTML rendering. 90 int ascent(FontBaseline baselineType = AlphabeticBaseline) const 91 { 92 if (baselineType == AlphabeticBaseline) 93 return lroundf(m_ascent); 94 return height() - height() / 2; 95 } 96 97 int descent(FontBaseline baselineType = AlphabeticBaseline) const 98 { 99 if (baselineType == AlphabeticBaseline) 100 return lroundf(m_descent); 101 return height() / 2; 102 } 103 104 int height(FontBaseline baselineType = AlphabeticBaseline) const 105 { 106 return ascent(baselineType) + descent(baselineType); 107 } 108 109 int lineGap() const { return lroundf(m_lineGap); } 110 int lineSpacing() const { return lroundf(m_lineSpacing); } 111 112 bool hasIdenticalAscentDescentAndLineGap(const FontMetrics& other) const 113 { 114 return ascent() == other.ascent() && descent() == other.descent() && lineGap() == other.lineGap(); 115 } 116 117 float zeroWidth() const { return m_zeroWidth; } 118 void setZeroWidth(float zeroWidth) 119 { 120 m_zeroWidth = zeroWidth; 121 m_hasZeroWidth = true; 122 } 123 124 bool hasZeroWidth() const { return m_hasZeroWidth; } 125 void setHasZeroWidth(bool hasZeroWidth) { m_hasZeroWidth = hasZeroWidth; } 126 127 float underlineThickness() const { return m_underlinethickness; } 128 void setUnderlineThickness(float underlineThickness) { m_underlinethickness = underlineThickness; } 129 130 float underlinePosition() const { return m_underlinePosition; } 131 void setUnderlinePosition(float underlinePosition) { m_underlinePosition = underlinePosition; } 132 133 private: 134 friend class SimpleFontData; 135 136 void reset() 137 { 138 m_unitsPerEm = gDefaultUnitsPerEm; 139 m_ascent = 0; 140 m_descent = 0; 141 m_lineGap = 0; 142 m_lineSpacing = 0; 143 m_xHeight = 0; 144 m_hasXHeight = false; 145 m_underlinethickness = 0; 146 m_underlinePosition = 0; 147 } 148 149 unsigned m_unitsPerEm; 150 float m_ascent; 151 float m_descent; 152 float m_lineGap; 153 float m_lineSpacing; 154 float m_xHeight; 155 float m_zeroWidth; 156 float m_underlinethickness; 157 float m_underlinePosition; 158 bool m_hasXHeight; 159 bool m_hasZeroWidth; 160 }; 161 162 inline float scaleEmToUnits(float x, unsigned unitsPerEm) 163 { 164 return unitsPerEm ? x / unitsPerEm : x; 165 } 166 167 } // namespace blink 168 169 #endif // FontMetrics_h 170
