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 <wtf/MathExtras.h>
24 
25 namespace WebCore {
26 
27 const unsigned gDefaultUnitsPerEm = 1000;
28 
29 class FontMetrics {
30 public:
FontMetrics()31     FontMetrics()
32         : m_unitsPerEm(gDefaultUnitsPerEm)
33         , m_ascent(0)
34         , m_descent(0)
35         , m_lineGap(0)
36         , m_lineSpacing(0)
37         , m_xHeight(0)
38     {
39     }
40 
unitsPerEm()41     unsigned unitsPerEm() const { return m_unitsPerEm; }
setUnitsPerEm(unsigned unitsPerEm)42     void setUnitsPerEm(unsigned unitsPerEm) { m_unitsPerEm = unitsPerEm; }
43 
44     float floatAscent(FontBaseline baselineType = AlphabeticBaseline) const
45     {
46         if (baselineType == AlphabeticBaseline)
47             return m_ascent;
48         return floatHeight() / 2;
49     }
50 
setAscent(float ascent)51     void setAscent(float ascent) { m_ascent = ascent; }
52 
53     float floatDescent(FontBaseline baselineType = AlphabeticBaseline) const
54     {
55         if (baselineType == AlphabeticBaseline)
56             return m_descent;
57         return floatHeight() / 2;
58     }
59 
setDescent(float descent)60     void setDescent(float descent) { m_descent = descent; }
61 
62     float floatHeight(FontBaseline baselineType = AlphabeticBaseline) const
63     {
64         return floatAscent(baselineType) + floatDescent(baselineType);
65     }
66 
floatLineGap()67     float floatLineGap() const { return m_lineGap; }
setLineGap(float lineGap)68     void setLineGap(float lineGap) { m_lineGap = lineGap; }
69 
floatLineSpacing()70     float floatLineSpacing() const { return m_lineSpacing; }
setLineSpacing(float lineSpacing)71     void setLineSpacing(float lineSpacing) { m_lineSpacing = lineSpacing; }
72 
xHeight()73     float xHeight() const { return m_xHeight; }
setXHeight(float xHeight)74     void setXHeight(float xHeight) { m_xHeight = xHeight; }
75 
76     // Integer variants of certain metrics, used for HTML rendering.
77     int ascent(FontBaseline baselineType = AlphabeticBaseline) const
78     {
79         if (baselineType == AlphabeticBaseline)
80             return lroundf(m_ascent);
81         return height() - height() / 2;
82     }
83 
84     int descent(FontBaseline baselineType = AlphabeticBaseline) const
85     {
86         if (baselineType == AlphabeticBaseline)
87             return lroundf(m_descent);
88         return height() / 2;
89     }
90 
91     int height(FontBaseline baselineType = AlphabeticBaseline) const
92     {
93         return ascent(baselineType) + descent(baselineType);
94     }
95 
lineGap()96     int lineGap() const { return lroundf(m_lineGap); }
lineSpacing()97     int lineSpacing() const { return lroundf(m_lineSpacing); }
98 
hasIdenticalAscentDescentAndLineGap(const FontMetrics & other)99     bool hasIdenticalAscentDescentAndLineGap(const FontMetrics& other) const
100     {
101         return ascent() == other.ascent() && descent() == other.descent() && lineGap() == other.lineGap();
102     }
103 
104 private:
105     friend class SimpleFontData;
106 
reset()107     void reset()
108     {
109         m_unitsPerEm = gDefaultUnitsPerEm;
110         m_ascent = 0;
111         m_descent = 0;
112         m_lineGap = 0;
113         m_lineSpacing = 0;
114         m_xHeight = 0;
115     }
116 
117     unsigned m_unitsPerEm;
118     float m_ascent;
119     float m_descent;
120     float m_lineGap;
121     float m_lineSpacing;
122     float m_xHeight;
123 };
124 
125 } // namespace WebCore
126 
127 #endif // FontMetrics_h
128