Improved titlebar buffering.

Are these commits going into the KDE2.1final, or do I need to do
something special?

svn path=/trunk/kdebase/kwin/; revision=81613

clients/kwmtheme/kwmthemeclient.cpp

@@ -290,9 +290,18 @@ KWMThemeClient::KWMThemeClient( Workspace *ws, WId w, QWidget *parent,
     setBackgroundMode(NoBackground);
 }
 
-void KWMThemeClient::drawTitle(QPainter &p)
+void KWMThemeClient::drawTitle(QPainter &dest)
 {
-    QRect r = titlebar->geometry();
+    QRect titleRect = titlebar->geometry();
+    QRect r(0, 0, titleRect.width(), titleRect.height());
+    QPixmap buffer;
+
+    if(buffer.width() == r.width())
+        return;
+
+    buffer.resize(r.size());
+    QPainter p;
+    p.begin(&buffer);
 
     if(titleSunken){
         qDrawShadeRect(&p, r, options->colorGroup(Options::Frame, isActive()),
@@ -324,8 +333,12 @@ void KWMThemeClient::drawTitle(QPainter &p)
     r.setLeft(r.left()+5);
     r.setRight(r.right()-5);
     p.drawText(r, titleAlign, caption());
+    p.end();
+
+    dest.drawPixmap(titleRect.x(), titleRect.y(), buffer);
 }
 
+
 void KWMThemeClient::resizeEvent( QResizeEvent* e)
 {
     Client::resizeEvent( e );

clients/kwmtheme/kwmthemeclient.h

@@ -40,6 +40,7 @@ protected:
 protected slots:
     void slotReset();
 private:
+    QPixmap buffer;
     KPixmap *aGradient, *iGradient;
     MyButton *maxBtn, *stickyBtn;
     QSpacerItem *titlebar;