From 333040706b4ca0853ea0d56d3ab4ca54b42a15dc Mon Sep 17 00:00:00 2001
From: Enrico Forestieri <forenr@lyx.org>
Date: Wed, 21 Mar 2007 23:13:32 +0000
Subject: [PATCH] Cache char right bearings

	* src/frontends/qt4/GuiFontMetrics.C
	(GuiFontMetrics::rbearing): Cache char rbearing.

	* src/frontends/qt4/GuiFontMetrics.h:
	Implement rbearing_cache_ as a QHash.


git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@17499 a592a061-630c-0410-9148-cb99ea01b6c8
---
 src/frontends/qt4/GuiFontMetrics.C | 10 +++++++---
 src/frontends/qt4/GuiFontMetrics.h |  3 +++
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/src/frontends/qt4/GuiFontMetrics.C b/src/frontends/qt4/GuiFontMetrics.C
index 9726bb0a31..0421b5a059 100644
--- a/src/frontends/qt4/GuiFontMetrics.C
+++ b/src/frontends/qt4/GuiFontMetrics.C
@@ -59,9 +59,13 @@ int GuiFontMetrics::lbearing(char_type c) const
 
 int GuiFontMetrics::rbearing(char_type c) const
 {
-	// Qt rbearing is from the right edge of the char's width().
-	QChar sc = ucs4_to_qchar(c);
-	return metrics_.width(sc) - metrics_.rightBearing(sc);
+	if (!rbearing_cache_.contains(c)) {
+		// Qt rbearing is from the right edge of the char's width().
+		QChar sc = ucs4_to_qchar(c);
+		int rb = metrics_.width(sc) - metrics_.rightBearing(sc);
+		rbearing_cache_.insert(c, rb);
+	}
+	return rbearing_cache_.value(c);
 }
 
 
diff --git a/src/frontends/qt4/GuiFontMetrics.h b/src/frontends/qt4/GuiFontMetrics.h
index 59a03c3a47..fc071f2684 100644
--- a/src/frontends/qt4/GuiFontMetrics.h
+++ b/src/frontends/qt4/GuiFontMetrics.h
@@ -75,6 +75,9 @@ private:
 	mutable QHash<char_type, AscendDescend> metrics_cache_;
 	/// fill in \c metrics_cache_ at specified value.
 	void fillMetricsCache(char_type) const;
+
+	/// Cache of char right bearings
+	mutable QHash<char_type, int> rbearing_cache_;
 };
 
 } // namespace frontend