Add Xorg composition support to kdm

KDM composition can be enabled in the control center
When enabled, it provides seamless composited logins to Trinity sessions
It also gets rid of the remaining artifacts in the themed kdm login screen


git-svn-id: svn://anonsvn.kde.org/home/kde/branches/trinity/kdebase@1246834 283d02a7-25f6-0310-bc7c-ecb5cbfe19da

1 files changed, 30 insertions, 10 deletions

diff --git a/kdm/kfrontend/themer/kdmthemer.cpp b/kdm/kfrontend/themer/kdmthemer.cpp
index d6b2e6e0e..39a1abe81 100644
--- a/kdm/kfrontend/themer/kdmthemer.cpp
+++ b/kdm/kfrontend/themer/kdmthemer.cpp
@@ -46,6 +46,8 @@
 
 #include <unistd.h>
 
+extern bool argb_visual_available;
+
 /*
  * KdmThemer. The main theming interface
  */
@@ -159,17 +161,35 @@ KdmThemer::widgetEvent( TQEvent *e )
 			TQRect paintRect = TQT_TQPAINTEVENT(e)->rect();
 			kdDebug() << timestamp() << " paint on: " << paintRect << endl;
 
-			if (!backBuffer)
-				backBuffer = new TQPixmap( widget()->size() );
-			if (backBuffer->size() != widget()->size())
-				backBuffer->resize( widget()->size() );
-
-			TQPainter p;
-			p.begin( backBuffer );
-			rootItem->paint( &p, paintRect );
-			p.end();
+			if ((_compositor.isEmpty()) || (!argb_visual_available)) {
+				// Software blend only (no compositing support)
+				if (!backBuffer)
+					backBuffer = new TQPixmap( widget()->size() );
+				if (backBuffer->size() != widget()->size())
+					backBuffer->resize( widget()->size() );
+	
+				TQPainter p;
+				p.begin( backBuffer );
+				rootItem->paint( &p, paintRect );
+				p.end();
+	
+				bitBlt( widget(), paintRect.topLeft(), backBuffer, paintRect );
+			}
+			else {
+				// We have compositing support!
+				TQRgb blend_color = tqRgba(0, 0, 0, 0);   // RGBA
+				float alpha = tqAlpha(blend_color) / 255.;
+				int pixel = tqAlpha(blend_color) << 24 |
+						int(tqRed(blend_color) * alpha) << 16 |
+						int(tqGreen(blend_color) * alpha) << 8  |
+						int(tqBlue(blend_color) * alpha);
+				TQPainter p1;
+				p1.begin( widget() );
+				p1.fillRect( paintRect, TQColor(blend_color, pixel) );
+				rootItem->paint( &p1, paintRect );
+				p1.end();
+			}
 
-			bitBlt( widget(), paintRect.topLeft(), backBuffer, paintRect );
 		}
 		break;
 	default: