Set the transformed geometry in WindowMotionManager when a window is dropped to a desktop in grid. This way the window does not jump to a random position on mouse release.

svn path=/trunk/KDE/kdebase/workspace/; revision=1104672

effects/desktopgrid/desktopgrid.cpp

@@ -638,10 +638,16 @@ void DesktopGridEffect::windowInputMouseEvent( Window, QEvent* e )
                     {
                     if( windowMove->isOnAllDesktops() )
                         {
+                        const int targetDesktop = posToDesktop( cursorPos() );
                         for( int i=0; i<effects->numberOfDesktops(); ++i )
                             {
                             WindowMotionManager& manager = m_managers[ (i)*(effects->numScreens()) + windowMove->screen() ];
                             manager.manage( windowMove );
+                            if( i+1 == targetDesktop )
+                                {
+                                // for the desktop the window is dropped on, we use the current geometry
+                                manager.setTransformedGeometry( windowMove, moveGeometryToDesktop( targetDesktop ) );
+                                }
                             m_proxy->calculateWindowTransformations( manager.managedWindows(), windowMove->screen(), manager );
                             }
                         }
@@ -649,6 +655,7 @@ void DesktopGridEffect::windowInputMouseEvent( Window, QEvent* e )
                         {
                         WindowMotionManager& manager = m_managers[ (windowMove->desktop()-1)*(effects->numScreens()) + windowMove->screen() ];
                         manager.manage( windowMove );
+                        manager.setTransformedGeometry( windowMove, moveGeometryToDesktop( windowMove->desktop() ) );
                         m_proxy->calculateWindowTransformations( manager.managedWindows(), windowMove->screen(), manager );
                         }
                     effects->addRepaintFull();
@@ -1234,6 +1241,35 @@ bool DesktopGridEffect::isUsingPresentWindows() const
     return (m_proxy != NULL);
     }
 
+// transforms the geometry of the moved window to a geometry on the desktop
+// internal method only used when a window is dropped onto a desktop
+QRectF DesktopGridEffect::moveGeometryToDesktop( int desktop ) const
+    {
+    QPointF point = unscalePos( m_windowMoveGeometry.topLeft() + cursorPos() - m_windowMoveStartPoint );
+    const double scaleFactor = scale[ windowMove->screen() ];
+    if( posToDesktop( m_windowMoveGeometry.topLeft() + cursorPos() - m_windowMoveStartPoint ) != desktop )
+        {
+        // topLeft is not on the desktop - check other corners
+        // if all corners are not on the desktop the window is bigger than the desktop - no matter what it will look strange
+        if( posToDesktop( m_windowMoveGeometry.topRight() + cursorPos() - m_windowMoveStartPoint ) == desktop )
+            {
+            point = unscalePos( m_windowMoveGeometry.topRight() + cursorPos() - m_windowMoveStartPoint ) -
+                QPointF( m_windowMoveGeometry.width(), 0) / scaleFactor;
+            }
+        else if( posToDesktop( m_windowMoveGeometry.bottomLeft() + cursorPos() - m_windowMoveStartPoint ) == desktop )
+            {
+            point = unscalePos( m_windowMoveGeometry.bottomLeft() + cursorPos() - m_windowMoveStartPoint ) -
+                QPointF(0, m_windowMoveGeometry.height() ) / scaleFactor;
+            }
+        else if( posToDesktop( m_windowMoveGeometry.bottomRight() + cursorPos() - m_windowMoveStartPoint ) == desktop )
+            {
+            point = unscalePos( m_windowMoveGeometry.bottomRight() + cursorPos() - m_windowMoveStartPoint ) -
+                QPointF(m_windowMoveGeometry.width(), m_windowMoveGeometry.height() ) / scaleFactor;
+            }
+        }
+    return QRectF( point, m_windowMoveGeometry.size() / scaleFactor );
+    }
+
 } // namespace
 
 #include "desktopgrid.moc"

effects/desktopgrid/desktopgrid.h

@@ -75,6 +75,7 @@ class DesktopGridEffect
         void finish();
         bool isMotionManagerMovingWindows();
         bool isUsingPresentWindows() const;
+        QRectF moveGeometryToDesktop( int desktop ) const;
         
         QList<ElectricBorder> borderActivate;
         int zoomDuration;

lib/kwineffects.cpp

@@ -1316,6 +1316,13 @@ QRectF WindowMotionManager::transformedGeometry( EffectWindow *w ) const
     return geometry;
     }
 
+void WindowMotionManager::setTransformedGeometry( EffectWindow *w, const QRectF &geometry )
+    {
+    m_managedWindows[ w ].translation.setValue( geometry.topLeft() );
+    m_managedWindows[ w ].scale.setValue( QPointF( geometry.width()/qreal(w->width()),
+                                                   geometry.height()/qreal(w->height())));
+    }
+
 QRectF WindowMotionManager::targetGeometry( EffectWindow *w ) const
     {
     QRectF geometry( w->geometry() );

lib/kwineffects.h

@@ -1596,6 +1596,12 @@ class KWIN_EXPORT WindowMotionManager
          * window.
          */
         QRectF transformedGeometry( EffectWindow *w ) const;
+        /**
+         * Sets the current transformed geometry of a registered window to the given geometry.
+         * @see transformedGeometry
+         * @since 4.5
+         */
+        void setTransformedGeometry( EffectWindow *w, const QRectF &geometry );
         /**
          * Retrieve the current target geometry of a registered
          * window.