From 0e55f109c58cdb96c3ab52c40736e79e98c5f61e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lubo=C5=A1=20Lu=C5=88=C3=A1k?= <l.lunak@kde.org>
Date: Thu, 18 Oct 2007 17:58:08 +0000
Subject: [PATCH] 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 |  4 +++-
 events.cpp    | 10 +++++++++-
 workspace.cpp |  1 +
 workspace.h   |  1 +
 4 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/composite.cpp b/composite.cpp
index 6be611eecc..c63decd292 100644
--- a/composite.cpp
+++ b/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()
diff --git a/events.cpp b/events.cpp
index 922387010f..d6bb856677 100644
--- a/events.cpp
+++ b/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() )
diff --git a/workspace.cpp b/workspace.cpp
index a383bd15b7..9bcdd767f1 100644
--- a/workspace.cpp
+++ b/workspace.cpp
@@ -128,6 +128,7 @@ Workspace::Workspace( bool restore )
     cm_selection( NULL ),
     compositeRate( 0 ),
     overlay( None ),
+    overlay_visible( true ),
     transSlider( NULL ),
     transButton( NULL )
     {
diff --git a/workspace.h b/workspace.h
index e7733ee370..c038be6b3f 100644
--- a/workspace.h
+++ b/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;