4 * This file is part of LyX, the document processor.
5 * Licence details can be found in the file COPYING.
9 * \author Abdelrazak Younes
11 * Full author contact details are available in file CREDITS.
14 #ifndef FONT_METRICS_H
15 #define FONT_METRICS_H
17 #include "support/docstring.h"
20 * A class holding helper functions for determining
21 * the screen dimensions of fonts.
23 * The geometry is the standard typographical geometry,
26 * --------------+------------------<maxAscent
28 * <-------> (right bearing)
32 * origin>____ | oo oo | oo oo
34 * --------------+---ooooo--|--oooo-<baseline
37 * descent>______| oooo |
39 * --------------+----------+-------<maxDescent
49 virtual ~FontMetrics() {}
51 /// return the maximum ascent of the font
52 virtual int maxAscent() const = 0;
53 /// return the maximum descent of the font
54 virtual int maxDescent() const = 0;
55 /// return the ascent of the char in the font
56 virtual int ascent(lyx::char_type c) const = 0;
57 /// return the descent of the char in the font
58 virtual int descent(lyx::char_type c) const = 0;
59 /// return the left bearing of the char in the font
60 virtual int lbearing(lyx::char_type c) const = 0;
61 /// return the right bearing of the char in the font
62 virtual int rbearing(lyx::char_type c) const = 0;
63 /// return the width of the string in the font
64 virtual int width(lyx::char_type const * s, size_t n) const = 0;
66 virtual int signedWidth(lyx::docstring const & s) const = 0;
68 * fill in width,ascent,descent with the values for the
69 * given string in the font.
71 virtual void rectText(lyx::docstring const & str,
74 int & descent) const = 0;
76 * fill in width,ascent,descent with the values for the
77 * given string in the font for a button.
79 virtual void buttonText(lyx::docstring const & str,
82 int & descent) const = 0;
84 /// return the maximum descent of the font
85 inline int maxHeight() const {
86 return maxAscent() + maxDescent();
89 /// return the descent of the char in the font
90 inline int height(lyx::char_type c) const
92 return ascent(c) + descent(c);
95 /// return the inner width of the char in the font
96 inline int center(lyx::char_type c) const {
97 return (rbearing(c) - lbearing(c)) / 2;
100 /// return the width of the char in the font
101 inline int width(lyx::char_type c) const
103 lyx::char_type tmp[2] = { c, L'\0'};
104 return width(tmp, 1);
107 /// return the width of the string in the font
108 inline int width(lyx::docstring const & s) const
110 return s.empty() ? 0 : width(s.data(), s.length());
114 } // namespace frontend
117 #endif // FONT_METRICS_H