Fix kdm startup when compositor is not enabled

git-svn-id: svn://anonsvn.kde.org/home/kde/branches/trinity/kdebase@1246838 283d02a7-25f6-0310-bc7c-ecb5cbfe19da

kdm/config.def

@@ -1990,7 +1990,7 @@ Key: Compositor
 Type: string
 Default: ""
 User: greeter
-Instance: #*/""
+Instance: */"kompmgr"
 Comment:
  Compositor binary name, if compositing is desired. "" means no compositing support.
 Description:

kdm/kfrontend/kgapp.cpp

@@ -211,7 +211,7 @@ kg_main( const char *argv0 )
 	XSetErrorHandler( (XErrorHandler)0 );
 
 	GreeterApp *app;
-	if( argb_visual_available ) {
+	if ( (argb_visual_available == true) && (!_compositor.isEmpty()) ) {
 		app = new GreeterApp(dpyi);
 	}
 	else {

kdm/kfrontend/themer/kdmpixmap.cpp

@@ -246,9 +246,14 @@ KdmPixmap::drawContents( TQPainter *p, const TQRect &r )
 				scaledImage = pClass->pixmap.convertToImage();
 			} else {
 				kdDebug() << timestamp() << " convertFromImage smoothscale\n";
+				if (pClass->pixmap.isNull()) {
+					scaledImage = TQImage();
+				}
+				else {
 					TQImage tempImage = pClass->pixmap.convertToImage();
 					kdDebug() << timestamp() << " convertToImage done\n";
 					scaledImage = tempImage.smoothScale( area.width(), area.height() );
+				}
 				kdDebug() << timestamp() << " done\n";
 			}
 		} else {
@@ -256,7 +261,7 @@ KdmPixmap::drawContents( TQPainter *p, const TQRect &r )
                   {
 			scaledImage = pClass->pixmap.convertToImage();
                         // enforce rgba values for the latter
-                        scaledImage = scaledImage.convertDepth( 32 );
+                        if (!scaledImage.isNull()) scaledImage = scaledImage.convertDepth( 32 );
                   }
 		  else
 		    pClass->readyPixmap = pClass->pixmap;
@@ -265,7 +270,7 @@ KdmPixmap::drawContents( TQPainter *p, const TQRect &r )
 		if (haveTint || haveAlpha) {
 			// blend image(pix) with the given tint
 
-			scaledImage = scaledImage.convertDepth( 32 );
+			if (!scaledImage.isNull()) scaledImage = scaledImage.convertDepth( 32 );
 			int w = scaledImage.width();
 			int h = scaledImage.height();
 			float tint_red = float( pClass->tint.red() ) / 255;
@@ -293,7 +298,7 @@ KdmPixmap::drawContents( TQPainter *p, const TQRect &r )
 			// Apply the alpha in the same manner as above, exept we are now
 			// using the hardware blending engine for all painting
 			scaledImage = pClass->readyPixmap;
-			scaledImage = scaledImage.convertDepth( 32 );
+			if (!scaledImage.isNull()) scaledImage = scaledImage.convertDepth( 32 );
 			int w = scaledImage.width();
 			int h = scaledImage.height();