lyx_mirror/src/frontends/FontMetrics.h
André Pönitz fc6ce7cd08 rename LyXFont to Font except in tex2lyx
git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@18095 a592a061-630c-0410-9148-cb99ea01b6c8
2007-04-29 18:17:15 +00:00

127 lines
3.5 KiB
C++

// -*- C++ -*-
/**
* \file FontMetrics.h
* This file is part of LyX, the document processor.
* Licence details can be found in the file COPYING.
*
* \author unknown
* \author John Levon
* \author Abdelrazak Younes
*
* Full author contact details are available in file CREDITS.
*/
#ifndef FONT_METRICS_H
#define FONT_METRICS_H
#include "support/docstring.h"
/**
* A class holding helper functions for determining
* the screen dimensions of fonts.
*
* The geometry is the standard typographical geometry,
* as follows :
*
* --------------+------------------<maxAscent
* | |
* <-------> (right bearing)
* <-> (left bearing)
* char ascent>___ |
* ^ oooo | oooo
* origin>____ | oo oo | oo oo
* \| oo oo | oo oo
* --------------+---ooooo--|--oooo-<baseline
* | oo |
* char | oo oo |
* descent>______| oooo |
* <- width ->
* --------------+----------+-------<maxDescent
*
* Caution: All char_type and docstring arguments of any method of this class
* are no UCS4 chars or strings if the font is a symbol font. They simply
* denote the code points of the font instead. You have to keep this in mind
* when you implement the methods in a frontend. You must not pass these
* parameters to a unicode conversion function in particular.
*/
namespace lyx {
class Dimension;
namespace frontend {
class FontMetrics
{
public:
virtual ~FontMetrics() {}
/// return the maximum ascent of the font
virtual int maxAscent() const = 0;
/// return the maximum descent of the font
virtual int maxDescent() const = 0;
/// return default dimension of the font.
/// \warning \c width is set to zero.
virtual Dimension const defaultDimension() const = 0;
/// return the width of the char in the font
virtual int width(char_type c) const = 0;
/// return the ascent of the char in the font
virtual int ascent(char_type c) const = 0;
/// return the descent of the char in the font
virtual int descent(char_type c) const = 0;
/// return the left bearing of the char in the font
virtual int lbearing(char_type c) const = 0;
/// return the right bearing of the char in the font
virtual int rbearing(char_type c) const = 0;
/// return the width of the string in the font
virtual int width(docstring const & s) const = 0;
/// FIXME ??
virtual int signedWidth(docstring const & s) const = 0;
/// return char dimension for the font.
virtual Dimension const dimension(char_type c) const = 0;
/**
* fill in width,ascent,descent with the values for the
* given string in the font.
*/
virtual void rectText(docstring const & str,
int & width,
int & ascent,
int & descent) const = 0;
/**
* fill in width,ascent,descent with the values for the
* given string in the font for a button.
*/
virtual void buttonText(docstring const & str,
int & width,
int & ascent,
int & descent) const = 0;
/// return the maximum descent of the font
inline int maxHeight() const {
return maxAscent() + maxDescent();
}
/// return the descent of the char in the font
inline int height(char_type c) const
{
return ascent(c) + descent(c);
}
/// return the inner width of the char in the font
inline int center(char_type c) const {
return (rbearing(c) - lbearing(c)) / 2;
}
};
} // namespace frontend
class Font;
/// Implementation is in Application.cpp
frontend::FontMetrics const & theFontMetrics(Font const & f);
} // namespace lyx
#endif // FONT_METRICS_H