Use a separate InputOnly window covering whole screen because it

reportedly improves move/resize performance on some systems
for some reason which I fail to see, but oh well.
(http://lists.kde.org/?t=107302193400001&r=1&w=2)

svn path=/trunk/kdebase/kwin/; revision=293755

client.cpp

@@ -74,6 +74,7 @@ Client::Client( Workspace *ws )
         wspace( ws ),
         bridge( new Bridge( this )),
         move_faked_activity( false ),
+        move_resize_grab_window( None ),
         transient_for( NULL ),
         transient_for_id( None ),
         original_transient_for_id( None ),

client.h

@@ -239,6 +239,7 @@ class Client : public QObject, public KDecorationDefines
 
         void keyPressEvent( uint key_code ); // FRAME ??
         void updateMouseGrab();
+        Window moveResizeGrabWindow() const;
 
         const QPoint calculateGravitation( bool invert, int gravity = 0 ) const; // FRAME public?
 
@@ -389,6 +390,7 @@ private slots:
         bool buttonDown;
         bool moveResizeMode;
         bool move_faked_activity;
+        Window move_resize_grab_window;
         bool unrestrictedMoveResize;
         bool isMove() const 
             {
@@ -822,6 +824,11 @@ inline bool Client::hasUserTimeSupport() const
     return info->userTime() != -1U;
     }
 
+inline Window Client::moveResizeGrabWindow() const
+    {
+    return move_resize_grab_window;
+    }
+
 #ifdef NDEBUG
 kndbgstream& operator<<( kndbgstream& stream, const Client* );
 kndbgstream& operator<<( kndbgstream& stream, const ClientList& );

events.cpp

@@ -255,6 +255,12 @@ bool Workspace::workspaceEvent( XEvent * e )
                     return true;
                 }
         }
+    if( movingClient != NULL && movingClient->moveResizeGrabWindow() == e->xany.window
+        && ( e->type == MotionNotify || e->type == ButtonPress || e->type == ButtonRelease ))
+        {
+        if( movingClient->windowEvent( e ))
+            return true;
+        }
 
     switch (e->type) 
         {
@@ -1218,9 +1224,10 @@ bool Client::buttonReleaseEvent( Window w, int /*button*/, int state, int x, int
         XAllowEvents(qt_xdisplay(), SyncPointer, CurrentTime ); //qt_x_time);
         return true;
         }
-    if( w != frameId() && w != decorationId())
+    if( w != moveResizeGrabWindow())
         return true;
-
+    x = this->x(); // translate from grab window to local coords
+    y = this->y();
     if ( (state & ( Button1Mask & Button2Mask & Button3Mask )) == 0 )
         {
         buttonDown = FALSE;
@@ -1273,7 +1280,7 @@ static bool waitingMotionEvent()
 // return value matters only when filtering events before decoration gets them
 bool Client::motionNotifyEvent( Window w, int /*state*/, int x, int y, int x_root, int y_root )
     {
-    if( w != frameId() && w != decorationId())
+    if( w != frameId() && w != decorationId() && w != moveResizeGrabWindow())
         return true; // care only about the whole frame
     if ( !buttonDown ) 
         {
@@ -1283,7 +1290,11 @@ bool Client::motionNotifyEvent( Window w, int /*state*/, int x, int y, int x_roo
         mode = newmode;
         return false;
         }
-
+    if( w == moveResizeGrabWindow())
+        {
+        x = this->x(); // translate from grab window to local coords
+        y = this->y();
+        }
     if( !waitingMotionEvent())
         handleMoveResize( x, y, x_root, y_root );
     return true;

geometry.cpp

@@ -1706,14 +1706,26 @@ bool Client::startMoveResize()
     bool has_grab = false;
     if( mode == PositionCenter )
         setCursor( sizeAllCursor ); // change from arrow cursor if moving
-    if( XGrabPointer( qt_xdisplay(), frameId(), False,
+    // This reportedly improves smoothness of the moveresize operation,
+    // something with Enter/LeaveNotify events, looks like XFree performance problem or something *shrug*
+    // (http://lists.kde.org/?t=107302193400001&r=1&w=2)
+    XSetWindowAttributes attrs;
+    QRect r = workspace()->clientArea( FullArea, this );
+    move_resize_grab_window = XCreateWindow( qt_xdisplay(), workspace()->rootWin(), r.x(), r.y(),
+        r.width(), r.height(), 0, CopyFromParent, InputOnly, CopyFromParent, 0, &attrs );
+    XMapRaised( qt_xdisplay(), move_resize_grab_window );
+    if( XGrabPointer( qt_xdisplay(), move_resize_grab_window, False,
         ButtonPressMask | ButtonReleaseMask | PointerMotionMask | EnterWindowMask | LeaveWindowMask,
         GrabModeAsync, GrabModeAsync, None, cursor.handle(), qt_x_time ) == Success )
         has_grab = true;
     if( XGrabKeyboard( qt_xdisplay(), frameId(), False, GrabModeAsync, GrabModeAsync, qt_x_time ) == Success )
         has_grab = true;
     if( !has_grab ) // at least one grab is necessary in order to be able to finish move/resize
+        {
+        XDestroyWindow( qt_xdisplay(), move_resize_grab_window );
+        move_resize_grab_window = None;
         return false;
+        }
     if ( maximizeMode() != MaximizeRestore )
         resetMaximize();
     moveResizeMode = true;
@@ -1762,6 +1774,8 @@ void Client::leaveMoveResize()
         ungrabXServer();
     XUngrabKeyboard( qt_xdisplay(), qt_x_time );
     XUngrabPointer( qt_xdisplay(), qt_x_time );
+    XDestroyWindow( qt_xdisplay(), move_resize_grab_window );
+    move_resize_grab_window = None;
     workspace()->setClientIsMoving(0);
     if( move_faked_activity )
         workspace()->unfakeActivity( this );