Small optimization when hiding windows.

When a window is hidden, it will call releaseBuffer() on the backing
store which in turn will resize the window surface to a null rect. In
this case, there is no need to update the QImage with the data pointer
since it will be updated on the subsequent beginPaint() when the image
is resized to a valid size again. This also avoids doing unnecessary
locking on the FBSERV heap which still involves a context switch on
older versions of Symbian.

1 files changed, 4 insertions, 3 deletions

diff --git a/src/gui/painting/qwindowsurface_s60.cpp b/src/gui/painting/qwindowsurface_s60.cpp
index 85190c2..2618ce2 100644
--- a/src/gui/painting/qwindowsurface_s60.cpp
+++ b/src/gui/painting/qwindowsurface_s60.cpp
@@ -144,12 +144,13 @@ void QS60WindowSurface::setGeometry(const QRect& rect)
     if (rect == geometry())
         return;
 
+    QWindowSurface::setGeometry(rect);
+
     TRect nativeRect(qt_QRect2TRect(rect));
     User::LeaveIfError(d_ptr->bitmap->Resize(nativeRect.Size()));
 
-    updatePaintDeviceOnBitmap();
-
-    QWindowSurface::setGeometry(rect);
+    if (!rect.isNull())
+        updatePaintDeviceOnBitmap();
 }
 
 void QS60WindowSurface::lockBitmapHeap()