Move window_pix into Toplevel, allowing the backing pixmap to be kept even after a window is unmapped.

This is needed for effects to make use of unavailable windows, such as when closing a window.

svn path=/branches/work/kwin_composite/; revision=622777

client.cpp

@@ -28,6 +28,7 @@ License. See the file "COPYING" for the exact licensing terms.
 #include "atoms.h"
 #include "notifications.h"
 #include "rules.h"
+#include "scene.h"
 
 #include <X11/extensions/shape.h>
 #include <QX11Info>
@@ -63,12 +64,10 @@ namespace KWinInternal
  is done in manage().
  */
 Client::Client( Workspace *ws )
-    :   QObject( NULL ),
+    :   Toplevel( ws ),
         client( None ),
         wrapper( None ),
-        frame( None ),
         decoration( NULL ),
-        wspace( ws ),
         bridge( new Bridge( this )),
         move_faked_activity( false ),
         move_resize_grab_window( None ),
@@ -82,7 +81,7 @@ Client::Client( Workspace *ws )
         process_killer( NULL ),
         user_time( CurrentTime ), // not known yet
         allowed_actions( 0 ),
-        postpone_geometry_updates( 0 ),
+        block_geometry_updates( 0 ),
         pending_geometry_update( false ),
         shade_geometry_change( false ),
         border_left( 0 ),
@@ -111,7 +110,6 @@ Client::Client( Workspace *ws )
     deleting = false;
     keep_above = false;
     keep_below = false;
-    is_shape = false;
     motif_noborder = false;
     motif_may_move = true;
     motif_may_resize = true;
@@ -124,6 +122,7 @@ Client::Client( Workspace *ws )
     modal = false;
     noborder = false;
     user_noborder = false;
+    not_obscured = false;
     urgency = false;
     ignore_focus_stealing = false;
     demands_attention = false;
@@ -142,7 +141,7 @@ Client::Client( Workspace *ws )
     
     cmap = None;
     
-    frame_geometry = QRect( 0, 0, 100, 100 ); // so that decorations don't start with size being (0,0)
+    geom = QRect( 0, 0, 100, 100 ); // so that decorations don't start with size being (0,0)
     client_size = QSize( 100, 100 );
 
     // SELI initialize xsizehints??
@@ -155,9 +154,10 @@ Client::~Client()
     {
     assert(!moveResizeMode);
     assert( client == None );
-    assert( frame == None && wrapper == None );
+    assert( wrapper == None );
+//    assert( frameId() == None );
     assert( decoration == NULL );
-    assert( postpone_geometry_updates == 0 );
+    assert( block_geometry_updates == 0 );
     assert( !check_active_modal );
     delete info;
     delete bridge;
@@ -176,15 +176,15 @@ void Client::releaseWindow( bool on_shutdown )
     {
     assert( !deleting );
     deleting = true;
+    finishCompositing();
     workspace()->discardUsedWindowRules( this, true ); // remove ForceTemporarily rules
     StackingUpdatesBlocker blocker( workspace());
     if (moveResizeMode)
        leaveMoveResize();
     finishWindowRules();
-    ++postpone_geometry_updates;
+    ++block_geometry_updates;
-    // grab X during the release to make removing of properties, setting to withdrawn state
+    if( isNormalState()) // is mapped?
-    // and repareting to root an atomic operation (http://lists.kde.org/?l=kde-devel&m=116448102901184&w=2)
+        workspace()->addDamage( geometry());
-    grabXServer();
     setMappingState( WithdrawnState );
     setModal( false ); // otherwise its mainwindow wouldn't get focus
     hidden = true; // so that it's not considered visible anymore (can't use hideClient(), it would set flags)
@@ -222,12 +222,10 @@ void Client::releaseWindow( bool on_shutdown )
     client = None;
     XDestroyWindow( display(), wrapper );
     wrapper = None;
-    XDestroyWindow( display(), frame );
+    XDestroyWindow( display(), frameId());
-    frame = None;
+//    frame = None;
-    --postpone_geometry_updates; // don't use GeometryUpdatesBlocker, it would now set the geometry
+    --block_geometry_updates; // don't use GeometryUpdatesBlocker, it would now set the geometry
-    checkNonExistentClients();
     deleteClient( this, Allowed );
-    ungrabXServer();
     }
 
 // like releaseWindow(), but this one is called when the window has been already destroyed
@@ -236,12 +234,15 @@ void Client::destroyClient()
     {
     assert( !deleting );
     deleting = true;
+    finishCompositing();
     workspace()->discardUsedWindowRules( this, true ); // remove ForceTemporarily rules
     StackingUpdatesBlocker blocker( workspace());
     if (moveResizeMode)
        leaveMoveResize();
     finishWindowRules();
-    ++postpone_geometry_updates;
+    ++block_geometry_updates;
+    if( isNormalState()) // is mapped?
+        workspace()->addDamage( geometry());
     setModal( false );
     hidden = true; // so that it's not considered visible anymore
     workspace()->clientHidden( this );
@@ -251,10 +252,9 @@ void Client::destroyClient()
     client = None; // invalidate
     XDestroyWindow( display(), wrapper );
     wrapper = None;
-    XDestroyWindow( display(), frame );
+    XDestroyWindow( display(), frameId());
-    frame = None;
+//    frame = None;
-    --postpone_geometry_updates; // don't use GeometryUpdatesBlocker, it would now set the geometry
+    --block_geometry_updates; // don't use GeometryUpdatesBlocker, it would now set the geometry
-    checkNonExistentClients();
     deleteClient( this, Allowed );
     }
 
@@ -264,12 +264,11 @@ void Client::updateDecoration( bool check_workspace_pos, bool force )
                     || ( decoration != NULL && !noBorder())))
         return;
     bool do_show = false;
-    postponeGeometryUpdates( true );
+    blockGeometryUpdates( true );
     if( force )
         destroyDecoration();
     if( !noBorder())
         {
-        setMask( QRegion()); // reset shape mask
         decoration = workspace()->createDecoration( bridge );
         // TODO check decoration's minimum size?
         decoration->init();
@@ -284,15 +283,20 @@ void Client::updateDecoration( bool check_workspace_pos, bool force )
         workarea_diff_x = save_workarea_diff_x;
         workarea_diff_y = save_workarea_diff_y;
         do_show = true;
+        if( compositing() )
+            discardWindowPixmap();
+        if( scene != NULL )
+            scene->windowGeometryShapeChanged( this );
         }
     else
         destroyDecoration();
     if( check_workspace_pos )
         checkWorkspacePosition();
-    postponeGeometryUpdates( false );
+    blockGeometryUpdates( false );
     if( do_show )
         decoration->widget()->show();
     updateFrameExtents();
+    addDamageFull();
     }
 
 void Client::destroyDecoration()
@@ -310,6 +314,11 @@ void Client::destroyDecoration()
         move( grav );
         workarea_diff_x = save_workarea_diff_x;
         workarea_diff_y = save_workarea_diff_y;
+        if( compositing() )
+            discardWindowPixmap();
+        if( scene != NULL )
+            scene->windowGeometryShapeChanged( this );
+        addDamageFull();
         }
     }
 
@@ -322,7 +331,7 @@ void Client::checkBorderSizes()
     if( new_left == border_left && new_right == border_right
         && new_top == border_top && new_bottom == border_bottom )
         return;
-    GeometryUpdatesPostponer blocker( this );
+    GeometryUpdatesBlocker blocker( this );
     move( calculateGravitation( true ));
     border_left = new_left;
     border_right = new_right;
@@ -339,7 +348,7 @@ void Client::checkBorderSizes()
 
 void Client::detectNoBorder()
     {
-    if( Shape::hasShape( window()))
+    if( shape())
         {
         noborder = true;
         return;
@@ -427,47 +436,24 @@ void Client::setUserNoBorder( bool set )
 
 void Client::updateShape()
     {
+    if ( shape() )
+        XShapeCombineShape(display(), frameId(), ShapeBounding,
+                           clientPos().x(), clientPos().y(),
+                           window(), ShapeBounding, ShapeSet);
+    else
+        XShapeCombineMask( display(), frameId(), ShapeBounding, 0, 0,
+                           None, ShapeSet);
+    if( compositing() )
+        discardWindowPixmap();
+    if( scene != NULL )
+        scene->windowGeometryShapeChanged( this );
+    addDamageFull();
     // workaround for #19644 - shaped windows shouldn't have decoration
     if( shape() && !noBorder()) 
         {
         noborder = true;
         updateDecoration( true );
         }
-    if( shape())
-        {
-        XShapeCombineShape(display(), frameId(), ShapeBounding,
-                           clientPos().x(), clientPos().y(),
-                           window(), ShapeBounding, ShapeSet);
-        }
-    // !shape() mask setting is done in setMask() when the decoration
-    // calls it or when the decoration is created/destroyed
-
-    if( Shape::version() >= 0x11 ) // 1.1, has input shape support
-        { // There appears to be no way to find out if a window has input
-          // shape set or not, so always propagate the input shape
-          // (it's the same like the bounding shape by default).
-          // Also, build the shape using a helper window, not directly
-          // in the frame window, because the sequence set-shape-to-frame,
-          // remove-shape-of-client, add-input-shape-of-client has the problem
-          // that after the second step there's a hole in the input shape
-          // until the real shape of the client is added and that can make
-          // the window lose focus (which is a problem with mouse focus policies)
-        static Window helper_window = None;
-        if( helper_window == None )
-            helper_window = XCreateSimpleWindow( display(), rootWindow(),
-                0, 0, 1, 1, 0, 0, 0 );
-        XResizeWindow( display(), helper_window, width(), height());
-        XShapeCombineShape( display(), helper_window, ShapeInput, 0, 0,
-                           frameId(), ShapeBounding, ShapeSet );
-        XShapeCombineShape( display(), helper_window, ShapeInput,
-                           clientPos().x(), clientPos().y(),
-                           window(), ShapeBounding, ShapeSubtract );
-        XShapeCombineShape( display(), helper_window, ShapeInput,
-                           clientPos().x(), clientPos().y(),
-                           window(), ShapeInput, ShapeUnion );
-        XShapeCombineShape( display(), frameId(), ShapeInput, 0, 0,
-                           helper_window, ShapeInput, ShapeSet );
-        }
     }
 
 void Client::setMask( const QRegion& reg, int mode )
@@ -496,7 +482,11 @@ void Client::setMask( const QRegion& reg, int mode )
             xrects, rects.count(), ShapeSet, mode );
         delete[] xrects;
         }
-    updateShape();
+    if( compositing() )
+        discardWindowPixmap();
+    if( scene != NULL )
+        scene->windowGeometryShapeChanged( this );
+    addDamageFull();
     }
 
 QRegion Client::mask() const
@@ -745,7 +735,7 @@ void Client::setShade( ShadeMode mode )
         }
 
     assert( decoration != NULL ); // noborder windows can't be shaded
-    GeometryUpdatesPostponer blocker( this );
+    GeometryUpdatesBlocker blocker( this );
     // decorations may turn off some borders when shaded
     decoration->borders( border_left, border_right, border_top, border_bottom );
 
@@ -792,9 +782,13 @@ void Client::setShade( ShadeMode mode )
         // tell xcompmgr shade's done
         _shade = 2;
         XChangeProperty(display(), frameId(), atoms->net_wm_window_shade, XA_CARDINAL, 32, PropModeReplace, (unsigned char *) &_shade, 1L);    
+        if( isNormalState()) // is mapped?
+            workspace()->addDamage( geometry());
         }
     else 
         {
+        if( isNormalState()) // is mapped?
+            workspace()->addDamage( geometry());
         int h = height();
         shade_geometry_change = true;
         QSize s( sizeForClientSize( clientSize()));
@@ -929,8 +923,8 @@ void Client::setMappingState(int s)
     XChangeProperty(display(), window(), atoms->wm_state, atoms->wm_state, 32,
         PropModeReplace, (unsigned char *)data, 2);
 
-    if( was_unmanaged ) // manage() did postpone_geometry_updates = 1, now it's ok to finally set the geometry
+    if( was_unmanaged ) // manage() did block_geometry_updates = 1, now it's ok to finally set the geometry
-        postponeGeometryUpdates( false );
+        blockGeometryUpdates( false );
     }
 
 /*!
@@ -941,12 +935,17 @@ void Client::rawShow()
     {
     if( decoration != NULL )
         decoration->widget()->show(); // not really necessary, but let it know the state
-    XMapWindow( display(), frame );
+    XMapWindow( display(), frameId());
     if( !isShade())
         {
         XMapWindow( display(), wrapper );
         XMapWindow( display(), client );
         }
+    // XComposite invalidates backing pixmaps on unmap (minimize, different
+    // virtual desktop, etc.).  We kept the last known good pixmap around
+    // for use in effects, but now we want to have access to the new pixmap
+    if( compositing() )
+        discardWindowPixmap();
     }
 
 /*!
@@ -956,6 +955,7 @@ void Client::rawShow()
 */
 void Client::rawHide()
     {
+    workspace()->addDamage( geometry());
 // Here it may look like a race condition, as some other client might try to unmap
 // the window between these two XSelectInput() calls. However, they're supposed to
 // use XWithdrawWindow(), which also sends a synthetic event to the root window,
@@ -963,7 +963,7 @@ void Client::rawHide()
 // will be missed is also very minimal, so I don't think it's needed to grab the server
 // here.
     XSelectInput( display(), wrapper, ClientWinMask ); // avoid getting UnmapNotify
-    XUnmapWindow( display(), frame );
+    XUnmapWindow( display(), frameId());
     XUnmapWindow( display(), wrapper );
     XUnmapWindow( display(), client );
     XSelectInput( display(), wrapper, ClientWinMask | SubstructureNotifyMask );
@@ -1308,7 +1308,7 @@ QString Client::readName() const
         return KWin::readNameProperty( window(), XA_WM_NAME );
     }
     
-KWIN_COMPARE_PREDICATE( FetchNameInternalPredicate, const Client*, (!cl->isSpecialWindow() || cl->isToolbar()) && cl != value && cl->caption() == value->caption());
+KWIN_COMPARE_PREDICATE( FetchNameInternalPredicate, Client, const Client*, (!cl->isSpecialWindow() || cl->isToolbar()) && cl != value && cl->caption() == value->caption());
 
 void Client::setCaption( const QString& _s, bool force )
     {
@@ -1625,58 +1625,6 @@ bool Client::wantsInput() const
     return rules()->checkAcceptFocus( input || Ptakefocus );
     }
 
-bool Client::isDesktop() const
-    {
-    return windowType() == NET::Desktop;
-    }
-
-bool Client::isDock() const
-    {
-    return windowType() == NET::Dock;
-    }
-
-bool Client::isTopMenu() const
-    {
-    return windowType() == NET::TopMenu;
-    }
-
-
-bool Client::isMenu() const
-    {
-    return windowType() == NET::Menu && !isTopMenu(); // because of backwards comp.
-    }
-
-bool Client::isToolbar() const
-    {
-    return windowType() == NET::Toolbar;
-    }
-
-bool Client::isSplash() const
-    {
-    return windowType() == NET::Splash;
-    }
-
-bool Client::isUtility() const
-    {
-    return windowType() == NET::Utility;
-    }
-
-bool Client::isDialog() const
-    {
-    return windowType() == NET::Dialog;
-    }
-
-bool Client::isNormalWindow() const
-    {
-    return windowType() == NET::Normal;
-    }
-
-bool Client::isSpecialWindow() const
-    {
-    return isDesktop() || isDock() || isSplash() || isTopMenu()
-        || isToolbar(); // TODO
-    }
-
 NET::WindowType Client::windowType( bool direct, int supported_types ) const
     {
     NET::WindowType wt = info->windowType( supported_types );
@@ -1708,6 +1656,12 @@ NET::WindowType Client::windowType( bool direct, int supported_types ) const
     return wt;
     }
 
+bool Client::isSpecialWindow() const
+    {
+    return isDesktop() || isDock() || isSplash() || isTopMenu()
+        || isToolbar(); // TODO
+    }
+
 /*!
   Sets an appropriate cursor shape for the logical mouse position \a m
 
@@ -1804,46 +1758,24 @@ void Client::cancelAutoRaise()
     autoRaiseTimer = 0;
     }
 
-#ifndef NDEBUG
+double Client::opacity() const
-kdbgstream& operator<<( kdbgstream& stream, const Client* cl )
     {
-    if( cl == NULL )
+    if( info->opacity() == 0xffffffff )
-        return stream << "\'NULL_CLIENT\'";
+        return 1.0;
-    return stream << "\'ID:" << cl->window() << ";WMCLASS:" << cl->resourceClass() << ":" << cl->resourceName() << ";Caption:" << cl->caption() << "\'";
+    return info->opacity() * 1.0 / 0xffffffff;
     }
-kdbgstream& operator<<( kdbgstream& stream, const ClientList& list )
+
+void Client::setOpacity( double opacity )
     {
-    stream << "LIST:(";
+    opacity = qBound( 0.0, opacity, 1.0 );
-    bool first = true;
+    info->setOpacity( static_cast< unsigned long >( opacity * 0xffffffff ));
-    for( ClientList::ConstIterator it = list.begin();
+    // we'll react on PropertyNotify
-         it != list.end();
-         ++it )
-        {
-        if( !first )
-            stream << ":";
-        first = false;
-        stream << *it;
-        }
-    stream << ")";
-    return stream;
     }
-kdbgstream& operator<<( kdbgstream& stream, const ConstClientList& list )
+
+void Client::debug( kdbgstream& stream ) const
     {
-    stream << "LIST:(";
+    stream << "\'ID:" << window() << ";WMCLASS:" << resourceClass() << ":" << resourceName() << ";Caption:" << caption() << "\'";
-    bool first = true;
-    for( ConstClientList::ConstIterator it = list.begin();
-         it != list.end();
-         ++it )
-        {
-        if( !first )
-            stream << ":";
-        first = false;
-        stream << *it;
-        }
-    stream << ")";
-    return stream;
     }
-#endif
 
 QPixmap * kwin_get_menu_pix_hack()
     {

composite.cpp

@@ -299,6 +299,14 @@ void Toplevel::finishCompositing()
     damage_region = QRegion();
     }
 
+void Toplevel::discardWindowPixmap()
+    {
+    if( window_pix == None )
+        return;
+    XFreePixmap( display(), window_pix );
+    window_pix = None;
+    }
+
 Pixmap Toplevel::createWindowPixmap() const
     {
     assert( compositing());

events.cpp

@@ -1615,6 +1615,8 @@ bool Unmanaged::windowEvent( XEvent* e )
                 {
                 detectShape( handle());
                 addDamageFull();
+                if( compositing() )
+                    discardWindowPixmap();
                 if( scene != NULL )
                     scene->windowGeometryShapeChanged( this );
                 }

scene_basic.cpp

@@ -47,10 +47,9 @@ void SceneBasic::paint( QRegion, ToplevelList windows )
         QRect r = (*it)->geometry().intersect( QRect( 0, 0, displayWidth(), displayHeight()));
         if( !r.isEmpty())
             {
-            Pixmap pix = (*it)->createWindowPixmap();
+            Pixmap pix = (*it)->windowPixmap();
             XCopyArea( display(), pix, composite_pixmap, gc,
                 qMax( 0, -(*it)->x()), qMax( 0, -(*it)->y()), r.width(), r.height(), r.x(), r.y());
-            XFreePixmap( display(), pix );
             }
         }
     XCopyArea( display(), composite_pixmap, rootWindow(), gc, 0, 0, displayWidth(), displayHeight(), 0, 0 );

scene_opengl.cpp

@@ -622,8 +622,7 @@ void SceneOpenGL::Window::bindTexture()
         return;
         }
     // Get the pixmap with the window contents
-    Pixmap window_pix = toplevel->createWindowPixmap();
+    Pixmap pix = toplevel->windowPixmap();
-    Pixmap pix = window_pix;
     // HACK
     // When a window uses ARGB visual and has a decoration, the decoration
     // does use ARGB visual. When converting such window to a texture
@@ -698,21 +697,24 @@ void SceneOpenGL::Window::bindTexture()
                 }
             XFreeGC( display(), gc );
             }
-        // the pixmap is no longer needed, the texture will be updated
+        // if using copy_buffer, the pixmap is no longer needed, the
-        // only when the window changes anyway, so no need to cache
+        // texture will be updated only when the window changes anyway,
-        // the pixmap
+        // so no need to cache the pixmap
-        XFreePixmap( display(), pix );
+        if( copy_buffer )
+            XFreePixmap( display(), pix );
         texture_y_inverted = true;
         toplevel->resetDamage( toplevel->rect());
         }
     else if( tfp_mode )
         { // tfp mode, simply bind the pixmap to texture
+        // TODO what should the lifetime of bound_pixmap be?
         if( texture == None )
             glGenTextures( 1, &texture );
         if( bound_pixmap != None && !strict_binding ) // release old if needed
             {
             glXReleaseTexImageEXT( display(), bound_glxpixmap, GLX_FRONT_LEFT_EXT );
             glXDestroyGLXPixmap( display(), bound_glxpixmap );
+            // TODO bound_pixmap shouldn't always be freed
             XFreePixmap( display(), bound_pixmap );
             }
         static const int attrs[] =
@@ -765,10 +767,11 @@ void SceneOpenGL::Window::bindTexture()
                 }
             }
         glXWaitGL();
-        // the pixmap is no longer needed, the texture will be updated
+        // if using copy_buffer, the pixmap is no longer needed, the
-        // only when the window changes anyway, so no need to cache
+        // texture will be updated only when the window changes anyway,
-        // the pixmap
+        // so no need to cache the pixmap
-        XFreePixmap( display(), pix );
+        if( copy_buffer )
+            XFreePixmap( display(), pix );
         if( db )
             glDrawBuffer( GL_BACK );
         glXMakeContextCurrent( display(), glxbuffer, glxbuffer, ctxbuffer );
@@ -776,8 +779,6 @@ void SceneOpenGL::Window::bindTexture()
         texture_y_inverted = false;
         toplevel->resetDamage( toplevel->rect());
         }
-    if( copy_buffer )
-        XFreePixmap( display(), window_pix );
     }
 
 
@@ -839,7 +840,12 @@ void SceneOpenGL::Window::discardTexture()
             if( !strict_binding )
                 glXReleaseTexImageEXT( display(), bound_glxpixmap, GLX_FRONT_LEFT_EXT );
             glXDestroyGLXPixmap( display(), bound_glxpixmap );
-            XFreePixmap( display(), bound_pixmap );
+            // TODO this is broken, and may need changing anyway depending on
+            // how tfp_mode deals with the new windowPixmap()
+            if( bound_pixmap != toplevel->windowPixmap( false ) )
+                // if using copy_buffer, bound_pixmap is independent of
+                // windowPixmap(), so free it now
+                XFreePixmap( display(), bound_pixmap );
             bound_pixmap = None;
             bound_glxpixmap = None;
             }

scene_xrender.cpp

@@ -305,8 +305,7 @@ Picture SceneXrender::Window::picture()
     if( _picture == None && format != NULL )
         {
         // Get the pixmap with the window contents.
-        Pixmap window_pix = toplevel->createWindowPixmap();
+        Pixmap pix = toplevel->windowPixmap();
-        Pixmap pix = window_pix;
         // HACK the same alpha clear hack like with opengl, see there
         Client* c = dynamic_cast< Client* >( toplevel );
         bool alpha_clear = c != NULL && c->hasAlpha() && !c->noBorder();
@@ -336,10 +335,9 @@ Picture SceneXrender::Window::picture()
             XFreeGC( display(), gc );
             }
         _picture = XRenderCreatePicture( display(), pix, format, 0, 0 );
-        XFreePixmap( display(), pix ); // the picture owns the pixmap
 #ifdef ALPHA_CLEAR_COPY
         if( alpha_clear )
-            XFreePixmap( display(), window_pix );
+            XFreePixmap( display(), pix );
 #endif
         toplevel->resetDamage( toplevel->rect());
         }

toplevel.cpp

@@ -17,6 +17,7 @@ Toplevel::Toplevel( Workspace* ws )
     : vis( None )
     , id( None )
     , wspace( ws )
+    , window_pix( None )
     , damage_handle( None )
     , is_shape( false )
     {
@@ -25,6 +26,7 @@ Toplevel::Toplevel( Workspace* ws )
 Toplevel::~Toplevel()
     {
     assert( damage_handle == None );
+    discardWindowPixmap();
     }
 
 #ifndef NDEBUG

toplevel.h

@@ -53,7 +53,7 @@ class Toplevel
         bool isSplash() const;
         bool isUtility() const;
 
-        Pixmap createWindowPixmap() const;
+        Pixmap windowPixmap( bool allow_create = true ); // for use with compositing
         Visual* visual() const;
         bool shape() const;
         virtual double opacity() const = 0;
@@ -70,6 +70,8 @@ class Toplevel
         void setHandle( Window id );
         void detectShape( Window id );
         void damageNotifyEvent( XDamageNotifyEvent* e );
+        Pixmap createWindowPixmap() const;
+        void discardWindowPixmap();
         QRect geom;
         Visual* vis;
         int bit_depth;
@@ -78,6 +80,7 @@ class Toplevel
     private:
         Window id;
         Workspace* wspace;
+        Pixmap window_pix;
         Damage damage_handle;
         QRegion damage_region;
         bool is_shape;
@@ -189,6 +192,13 @@ inline bool Toplevel::isNormalWindow() const
     return windowType() == NET::Normal;
     }
 
+inline Pixmap Toplevel::windowPixmap( bool allow_create )
+    {
+    if( window_pix == None && allow_create )
+        window_pix = createWindowPixmap();
+    return window_pix;
+    }
+
 inline QRegion Toplevel::damage() const
     {
     return damage_region;