Don't do any compositing when nothing is visible anyway (e.g. when switched

away from the X session).


svn path=/trunk/KDE/kdebase/workspace/; revision=726713

composite.cpp

@@ -271,7 +271,8 @@ void Workspace::performCompositing()
     if( lastCompositePaint.elapsed() < 1 )
         return;
     checkCursorPos();
-    if( repaints_region.isEmpty() && !windowRepaintsPending()) // no damage
+    if(( repaints_region.isEmpty() && !windowRepaintsPending()) // no damage
+        || !overlay_visible ) // nothing is visible anyway
         {
         scene->idle();
         return;
@@ -365,6 +366,7 @@ void Workspace::setupOverlay( Window w )
         XMapWindow( display(), w );
         }
     XMapRaised( display(), overlay );
+    XSelectInput( display(), overlay, VisibilityChangeMask );
     }
 
 void Workspace::destroyOverlay()

events.cpp

@@ -455,8 +455,16 @@ bool Workspace::workspaceEvent( XEvent * e )
                 return true;
             break;
         case Expose:
-            if( e->xexpose.window == rootWindow() && compositing())  // root window needs repainting
+            if( compositing()
+                && ( e->xexpose.window == rootWindow()  // root window needs repainting
+                    || overlay != None && e->xexpose.window == overlay )) // overlay needs repainting
+                {
                 addRepaint( e->xexpose.x, e->xexpose.y, e->xexpose.width, e->xexpose.height );
+                }
+            break;
+        case VisibilityNotify:
+            if( compositing() && overlay != None && e->xvisibility.window == overlay )
+                overlay_visible = ( e->xvisibility.state != VisibilityFullyObscured );
             break;
         default:
             if( e->type == Extensions::randrNotifyEvent() && Extensions::randrAvailable() )

workspace.cpp

@@ -128,6 +128,7 @@ Workspace::Workspace( bool restore )
     cm_selection( NULL ),
     compositeRate( 0 ),
     overlay( None ),
+    overlay_visible( true ),
     transSlider( NULL ),
     transButton( NULL )
     {

workspace.h

@@ -715,6 +715,7 @@ class Workspace : public QObject, public KDecorationDefines
         int compositeRate;
         QRegion repaints_region;
         Window overlay; // XComposite overlay window
+        bool overlay_visible;
         QSlider *transSlider;
         QPushButton *transButton;