Cache width, ascent, and descent font metrics as their calculation may be

really expensive on some platforms.

	* src/frontends/qt2/qfont_loader.[Ch]
	(QLFontInfo::width): rename WidthCache as MetricsCache.
	(QLFontInfo::ascent,QLFontInfo::descent): new, return (possibly cached)
	ascent/descent values.

	* src/frontends/qt2/qfont_loader.h:
	implement cache for ascent/descent values in the QLFontInfo class.

	* src/frontends/qt2/qfont_metrics.C
	(ascent, descent): use the corresponding methods in QLFontInfo class.
	Remove support for obsolete Qt/Win 3.2.1nc.


git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/branches/BRANCH_1_4_X@16224 a592a061-630c-0410-9148-cb99ea01b6c8

src/frontends/qt2/ChangeLog

@@ -1,3 +1,14 @@
+2006-12-09  Enrico Forestieri  <forenr@tlc.unipr.it>
+
+	* qfont_loader.[Ch] (width): rename WidthCache as MetricsCache.
+	(ascent, descent): New, return (possibly cached) ascent/descent values.
+
+	* qfont_loader.h: Implement cache for ascent/descent values in the
+	QLFontInfo class.
+
+	* qfont_metrics.C (ascent, descent): use the corresponding methods
+	in QLFontInfo class. Remove support for obsolete Qt/Win 3.2.1nc.
+
 2006-10-27  Jean-Marc Lasgouttes  <lasgouttes@lyx.org>
 
 	* QtView.C (hasFocus): return a correct value now (and fix bug 1720).
@@ -6,6 +17,7 @@
 
 	* QDelimiterDialog.[Ch] (fix_name, QDelimiterDialog, insertClicked,
 	size_selected): Allow for fixed size delimiters.
+
 	* ui/QDelimiterDialogBase.ui: Added a combobox for selecting
 	delimiter size.
 

src/frontends/qt2/qfont_loader.C

@@ -364,7 +364,7 @@ int QLFontInfo::width(Uchar val)
 // Starting with version 3.1.0, Qt/X11 does its own caching of
 // character width, so it is not necessary to provide ours.
 #if defined (USE_LYX_FONTCACHE)
-	QLFontInfo::WidthCache::const_iterator cit = widthcache.find(val);
+	QLFontInfo::MetricsCache::const_iterator cit = widthcache.find(val);
 	if (cit != widthcache.end())
 		return cit->second;
 
@@ -377,6 +377,44 @@ int QLFontInfo::width(Uchar val)
 }
 
 
+int QLFontInfo::ascent(char c)
+{
+#if defined(USE_LYX_FONTCACHE)
+	Uchar const val = static_cast<Uchar>(c);
+	QLFontInfo::MetricsCache::const_iterator cit = ascentcache.find(val);
+	if (cit != ascentcache.end())
+		return cit->second;
+
+	QRect const & r = metrics.boundingRect(c);
+	int const w = -r.top();
+	ascentcache[val] = w;
+	return w;
+#else
+	QRect const & r = metrics.boundingRect(c);
+	return -r.top();
+#endif
+}
+
+
+int QLFontInfo::descent(char c)
+{
+#if defined(USE_LYX_FONTCACHE)
+	Uchar const val = static_cast<Uchar>(c);
+	QLFontInfo::MetricsCache::const_iterator cit = descentcache.find(val);
+	if (cit != descentcache.end())
+		return cit->second;
+
+	QRect const & r = metrics.boundingRect(c);
+	int const w = r.bottom() + 1;
+	descentcache[val] = w;
+	return w;
+#else
+	QRect const & r = metrics.boundingRect(c);
+	return r.bottom() + 1;
+#endif
+}
+
+
 bool FontLoader::available(LyXFont const & f)
 {
 	if (!lyx_gui::use_gui)

src/frontends/qt2/qfont_loader.h

@@ -18,7 +18,7 @@
 #include <qfont.h>
 #include <qfontmetrics.h>
 
-#if QT_VERSION < 0x030100 || defined(Q_WS_MACX)
+#ifndef I_AM_AFRAID_OF_FONTCACHE
 #define USE_LYX_FONTCACHE
 #endif
 
@@ -36,6 +36,10 @@ public:
 
 	/// Return pixel width for the given unicode char
 	int width(Uchar val);
+	/// Return the pixel ascent for the given unicode char
+	int ascent(char val);
+	/// Return the pixel descent for the given unicode char
+	int descent(char val);
 
 	/// The font instance
 	QFont font;
@@ -43,9 +47,13 @@ public:
 	QFontMetrics metrics;
 
 #if defined(USE_LYX_FONTCACHE)
-	typedef std::map<Uchar, int> WidthCache;
+	typedef std::map<Uchar, int> MetricsCache;
 	/// Cache of char widths
-	WidthCache widthcache;
+	MetricsCache widthcache;
+	/// Cache of char ascents
+	MetricsCache ascentcache;
+	/// Cache of char descents
+	MetricsCache descentcache;
 #endif
 };
 

src/frontends/qt2/qfont_metrics.C

@@ -46,15 +46,7 @@ int ascent(char c, LyXFont const & f)
 {
 	if (!lyx_gui::use_gui)
 		return 1;
-	QRect const & r = fontloader.metrics(f).boundingRect(c);
-	// Qt/Win 3.2.1nc (at least) corrects the GetGlyphOutlineA|W y
-	// value by the height: (x, -y-height, width, height).
-	// Other versions return: (x, -y, width, height)
-#if defined(Q_WS_WIN) && (QT_VERSION == 0x030201)
-	return -r.top() - r.height();
-#else
-	return -r.top();
-#endif
+	return fontloader.fontinfo(f).ascent(c);
 }
 
 
@@ -62,15 +54,7 @@ int descent(char c, LyXFont const & f)
 {
 	if (!lyx_gui::use_gui)
 		return 1;
-	QRect const & r = fontloader.metrics(f).boundingRect(c);
-	// Qt/Win 3.2.1nc (at least) corrects the GetGlyphOutlineA|W y
-	// value by the height: (x, -y-height, width, height).
-	// Other versions return: (x, -y, width, height)
-#if defined(Q_WS_WIN) && (QT_VERSION == 0x030201)
-	return r.bottom() + r.height() + 1;
-#else
-	return r.bottom() + 1;
-#endif
+	return fontloader.fontinfo(f).descent(c);
 }
 
 

status.14x

@@ -122,6 +122,8 @@ What's new
 
 - Don't reset cell selection when opening tabular dialog (bug 2715).
 
+- Fix slowness with lots of math on Windows (bug 2900).
+
 * Build/installation:
 
 - Allow autoconf 2.60 for building.