enable Font cache only for MacOSX and inline width() for other platform.

[lyx.git] / src / frontends / font_metrics.h

diff --git a/src/frontends/font_metrics.h b/src/frontends/font_metrics.h
index 71efcaebbc52f9c632065cac70dc5436ca64c103..9c6becdab9085e3a6b76aa861c404cf7e370119b 100644 (file)
--- a/src/frontends/font_metrics.h
+++ b/src/frontends/font_metrics.h
@@ -1,3 +1,103 @@
-//// temporary
+// -*- C++ -*-
+/**
+ * \file font_metrics.h
+ * This file is part of LyX, the document processor.
+ * Licence details can be found in the file COPYING.
+ *
+ * \author unknown
+ * \author John Levon
+ *
+ * Full author contact details are available in file CREDITS.
+ */
 
-#include "xforms/xfont_metrics.h"
+#ifndef FONT_METRICS_H
+#define FONT_METRICS_H
+
+#include "support/docstring.h"
+
+
+class LyXFont;
+
+/**
+ * A namespace 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
+ *
+ */
+namespace font_metrics {
+       /// return the maximum ascent of the font
+       int maxAscent(LyXFont const & f);
+       /// return the maximum descent of the font
+       int maxDescent(LyXFont const & f);
+       /// return the maximum descent of the font
+       inline int maxHeight(LyXFont const & f) {
+               return maxAscent(f) + maxDescent(f);
+       }
+       /// return the ascent of the char in the font
+       int ascent(lyx::char_type c, LyXFont const & f);
+       /// return the descent of the char in the font
+       int descent(lyx::char_type c, LyXFont const & f);
+       /// return the descent of the char in the font
+       inline int height(lyx::char_type c, LyXFont const & f)
+       {
+               return ascent(c, f) + descent(c, f);
+       }
+       /// return the left bearing of the char in the font
+       int lbearing(lyx::char_type c, LyXFont const & f);
+       /// return the right bearing of the char in the font
+       int rbearing(lyx::char_type c, LyXFont const & f);
+       /// return the inner width of the char in the font
+       inline int center(lyx::char_type c, LyXFont const & f) {
+               return (rbearing(c, f) - lbearing(c, f)) / 2;
+       }
+       /// return the width of the string in the font
+       int width(lyx::char_type const * s, size_t n, LyXFont const & f);
+       /// return the width of the char in the font
+       inline int width(lyx::char_type c, LyXFont const & f)
+       {
+               lyx::char_type tmp[2] = { c, L'\0'};
+               return width(tmp, 1, f);
+       }
+       /// return the width of the string in the font
+       inline int width(lyx::docstring const & s, LyXFont const & f)
+       {
+           return s.empty() ? 0 : width(s.data(), s.length(), f);
+       }
+       /// FIXME ??
+       int signedWidth(lyx::docstring const & s, LyXFont const & f);
+       /**
+        * fill in width,ascent,descent with the values for the
+        * given string in the font.
+        */
+       void rectText(lyx::docstring const & str, LyXFont const & font,
+               int & width,
+               int & ascent,
+               int & descent);
+       /**
+        * fill in width,ascent,descent with the values for the
+        * given string in the font for a button.
+        */
+       void buttonText(lyx::docstring const & str, LyXFont const & font,
+               int & width,
+               int & ascent,
+               int & descent);
+}
+
+#endif // FONT_METRICS_H