Show the composite overlay window only before the first painting pass

actually needs to flush the output to the screen. Avoids windows
temporarily disappearing during KDE startup or similar visual glitches.


svn path=/trunk/KDE/kdebase/workspace/; revision=806387

composite.cpp

@@ -372,14 +372,20 @@ void Workspace::setupOverlay( Window w )
     assert( Extensions::shapeInputAvailable());
     XShapeCombineRectangles( display(), overlay, ShapeInput, 0, 0, NULL, 0, ShapeSet, Unsorted );
     if( w != None )
-        {
         XShapeCombineRectangles( display(), w, ShapeInput, 0, 0, NULL, 0, ShapeSet, Unsorted );
-        XMapWindow( display(), w );
-        }
-    XMapRaised( display(), overlay );
     XSelectInput( display(), overlay, VisibilityChangeMask );
     }
 
+void Workspace::showOverlay()
+    {
+    assert( overlay != None );
+    if( overlay_shown )
+        return;
+    XMapSubwindows( display(), overlay );
+    XMapWindow( display(), overlay );
+    overlay_shown = true;
+    }
+
 void Workspace::destroyOverlay()
     {
     if( overlay == None )
@@ -388,6 +394,7 @@ void Workspace::destroyOverlay()
     XCompositeReleaseOverlayWindow( display(), overlay );
 #endif
     overlay = None;
+    overlay_shown = false;
     }
 
 //****************************************

scene_opengl.cpp

@@ -638,6 +638,8 @@ void SceneOpenGL::waitSync()
 // actually paint to the screen (double-buffer swap or copy from pixmap buffer)
 void SceneOpenGL::flushBuffer( int mask, QRegion damage )
     {
+    if( wspace->overlayWindow()) // show the window only after the first pass, since
+        wspace->showOverlay();   // that pass may take long
     if( db )
         {
         if( mask & PAINT_SCREEN_REGION )

scene_xrender.cpp

@@ -170,6 +170,8 @@ void SceneXrender::paint( QRegion damage, ToplevelList toplevels )
         }
     int mask = 0;
     paintScreen( &mask, &damage );
+    if( wspace->overlayWindow()) // show the window only after the first pass, since
+        wspace->showOverlay();   // that pass may take long
     if( mask & PAINT_SCREEN_REGION )
         {
         // Use the damage region as the clip region for the root window

workspace.cpp

@@ -137,6 +137,7 @@ Workspace::Workspace( bool restore )
     compositeRate( 0 ),
     overlay( None ),
     overlay_visible( true ),
+    overlay_shown( false ),
     transSlider( NULL ),
     transButton( NULL )
     {

workspace.h

@@ -318,6 +318,7 @@ class Workspace : public QObject, public KDecorationDefines
         bool createOverlay();
         // init overlay and the destination window in it
         void setupOverlay( Window window );
+        void showOverlay();
         // destroys XComposite overlay window
         void destroyOverlay();
         Window overlayWindow();
@@ -723,6 +724,7 @@ class Workspace : public QObject, public KDecorationDefines
         QRegion repaints_region;
         Window overlay; // XComposite overlay window
         bool overlay_visible;
+        bool overlay_shown; // for showOverlay()
         QSlider *transSlider;
         QPushButton *transButton;