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 WebCore {
27
28 const unsigned gDefaultUnitsPerEm = 1000;
29
30 class FontMetrics {
31 public:
FontMetrics()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
unitsPerEm()47 unsigned unitsPerEm() const { return m_unitsPerEm; }
setUnitsPerEm(unsigned 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
setAscent(float ascent)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
setDescent(float descent)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
floatLineGap()73 float floatLineGap() const { return m_lineGap; }
setLineGap(float lineGap)74 void setLineGap(float lineGap) { m_lineGap = lineGap; }
75
floatLineSpacing()76 float floatLineSpacing() const { return m_lineSpacing; }
setLineSpacing(float lineSpacing)77 void setLineSpacing(float lineSpacing) { m_lineSpacing = lineSpacing; }
78
xHeight()79 float xHeight() const { return m_xHeight; }
setXHeight(float xHeight)80 void setXHeight(float xHeight)
81 {
82 m_xHeight = xHeight;
83 m_hasXHeight = true;
84 }
85
hasXHeight()86 bool hasXHeight() const { return m_hasXHeight && m_xHeight > 0; }
setHasXHeight(bool hasXHeight)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
lineGap()109 int lineGap() const { return lroundf(m_lineGap); }
lineSpacing()110 int lineSpacing() const { return lroundf(m_lineSpacing); }
111
hasIdenticalAscentDescentAndLineGap(const FontMetrics & other)112 bool hasIdenticalAscentDescentAndLineGap(const FontMetrics& other) const
113 {
114 return ascent() == other.ascent() && descent() == other.descent() && lineGap() == other.lineGap();
115 }
116
zeroWidth()117 float zeroWidth() const { return m_zeroWidth; }
setZeroWidth(float zeroWidth)118 void setZeroWidth(float zeroWidth)
119 {
120 m_zeroWidth = zeroWidth;
121 m_hasZeroWidth = true;
122 }
123
hasZeroWidth()124 bool hasZeroWidth() const { return m_hasZeroWidth; }
setHasZeroWidth(bool hasZeroWidth)125 void setHasZeroWidth(bool hasZeroWidth) { m_hasZeroWidth = hasZeroWidth; }
126
underlineThickness()127 float underlineThickness() const { return m_underlinethickness; }
setUnderlineThickness(float underlineThickness)128 void setUnderlineThickness(float underlineThickness) { m_underlinethickness = underlineThickness; }
129
underlinePosition()130 float underlinePosition() const { return m_underlinePosition; }
setUnderlinePosition(float underlinePosition)131 void setUnderlinePosition(float underlinePosition) { m_underlinePosition = underlinePosition; }
132
133 private:
134 friend class SimpleFontData;
135
reset()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
scaleEmToUnits(float x,unsigned unitsPerEm)162 inline float scaleEmToUnits(float x, unsigned unitsPerEm)
163 {
164 return unitsPerEm ? x / unitsPerEm : x;
165 }
166
167 } // namespace WebCore
168
169 #endif // FontMetrics_h
170