Forward wheel events to the wallpaper

svn path=/trunk/KDE/kdebase/workspace/libs/plasma/; revision=857101

containment.cpp

@@ -991,6 +991,20 @@ void Containment::keyPressEvent(QKeyEvent *event)
 
 void Containment::wheelEvent(QGraphicsSceneWheelEvent *event)
 {
+    if (d->wallpaper) {
+        QGraphicsItem* item = scene()->itemAt(event->scenePos());
+        if (item == this) {
+            event->ignore();
+            d->wallpaper->mouseWheelEvent(event);
+
+            if (event->isAccepted()) {
+                return;
+            }
+
+            event->accept();
+        }
+    }
+
     if (containmentType() == DesktopContainment) {
         QGraphicsItem* item = scene()->itemAt(event->scenePos());
         if (item == this) {

wallpaper.cpp

@@ -217,6 +217,11 @@ void Wallpaper::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
     Q_UNUSED(event)
 }
 
+void Wallpaper::mouseWheelEvent(QGraphicsSceneWheelEvent *event)
+{
+    Q_UNUSED(event)
+}
+
 } // Plasma namespace
 
 #include "wallpaper.moc"

wallpaper.h

@@ -186,6 +186,14 @@ class PLASMA_EXPORT Wallpaper : public QObject
          */
         virtual void mouseReleaseEvent(QGraphicsSceneMouseEvent *event);
 
+        /**
+         * Mouse wheel event. To prevent further propagation of the event,
+         * the event must be accepted.
+         *
+         * @param event the wheel event object
+         */
+        virtual void mouseWheelEvent(QGraphicsSceneWheelEvent *event);
+
     Q_SIGNALS:
         /**
          * This signal indicates that wallpaper needs to be repainted.