Enable dynamic [de|con]struction of window surfaces based on visibility

When a window becomes completely obscured either because it has been
hidden or another window is completely covering it, the backing store
should be deallocated to save memory and then re-allocated when the
window is later made visible again.

Reviewed-by: Iain <qt-info@nokia.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/src/gui/kernel/qwidget_s60.cpp b/src/gui/kernel/qwidget_s60.cpp
index 116dc35..ec80a18 100644
--- a/src/gui/kernel/qwidget_s60.cpp
+++ b/src/gui/kernel/qwidget_s60.cpp
@@ -195,12 +195,13 @@ void QWidgetPrivate::create_sys(WId window, bool initializeWindow, bool destroyO
             data.crect.moveTopLeft(QPoint(clientRect.iTl.iX, clientRect.iTl.iY));
         QSymbianControl *control= new QSymbianControl(q);
         control->ConstructL(true,desktop);
-        if (!desktop)
-        {
+        if (!desktop) {
             QTLWExtra *topExtra = topData();
             topExtra->rwindow = control->DrawableWindow();
             // Request mouse move events.
-            topExtra->rwindow->PointerFilter(EPointerFilterEnterExit | EPointerFilterMove | EPointerFilterDrag, 0);
+            topExtra->rwindow->PointerFilter(EPointerFilterEnterExit
+                | EPointerFilterMove | EPointerFilterDrag, 0);
+            topExtra->rwindow->EnableVisibilityChangeEvents();
         }
 
         id = (WId)control;