Remove unnecessary resizes during orientation change

Orientation change causes unnecessary resize to top
level window on Symbian. This causes recreation of
EGL surfaces which is not wanted.

Task-number: QTBUG-19911
Reviewed-by: Sami Merila

3 files changed, 18 insertions, 1 deletions

diff --git a/src/gui/kernel/qapplication_s60.cpp b/src/gui/kernel/qapplication_s60.cpp
index 96b82da..98f00fb 100644
--- a/src/gui/kernel/qapplication_s60.cpp
+++ b/src/gui/kernel/qapplication_s60.cpp
@@ -1524,7 +1524,8 @@ void QSymbianControl::HandleResourceChange(int resourceType)
         // client area.
         if (S60->statusPane() && (S60->statusPane()->IsVisible() || m_lastStatusPaneVisibility)) {
             m_lastStatusPaneVisibility = S60->statusPane()->IsVisible();
-            handleClientAreaChange();
+            if (S60->handleStatusPaneResizeNotifications)
+                handleClientAreaChange();
         }
         if (IsFocused() && IsVisible()) {
             qwidget->d_func()->setWindowIcon_sys(true);
diff --git a/src/gui/kernel/qt_s60_p.h b/src/gui/kernel/qt_s60_p.h
index c4ddc26..fccb44d 100644
--- a/src/gui/kernel/qt_s60_p.h
+++ b/src/gui/kernel/qt_s60_p.h
@@ -154,6 +154,7 @@ public:
     int orientationSet : 1;
     int partial_keyboard : 1;
     int partialKeyboardOpen : 1;
+    int handleStatusPaneResizeNotifications : 1;
     QApplication::QS60MainApplicationFactory s60ApplicationFactory; // typedef'ed pointer type
     QPointer<QWidget> splitViewLastWidget;
 
@@ -343,6 +344,7 @@ inline QS60Data::QS60Data()
   orientationSet(0),
   partial_keyboard(0),
   partialKeyboardOpen(0),
+  handleStatusPaneResizeNotifications(1),
   s60ApplicationFactory(0)
 #ifdef Q_OS_SYMBIAN
   ,s60InstalledTrapHandler(0)
diff --git a/src/gui/s60framework/qs60mainappui.cpp b/src/gui/s60framework/qs60mainappui.cpp
index 4f08fe2..e2ec78c 100644
--- a/src/gui/s60framework/qs60mainappui.cpp
+++ b/src/gui/s60framework/qs60mainappui.cpp
@@ -315,7 +315,21 @@ TRect QS60MainAppUi::ApplicationRect() const
 */
 void QS60MainAppUi::HandleScreenDeviceChangedL()
 {
+    // This function triggers AppUi relayout which also generates
+    // HandleStatusPaneSizeChange(). We don't want to handle
+    // status pane resizes at this point because it causes
+    // Qt window resize and thus EGL surface resize in the middle of
+    // incomplete layout process causing unnecessary overhead.
+    // To prevent status pane resize handling while layout is still
+    // in progress, we guard relayouting with handleStatusPaneResizeNotifications
+    // flag. QSymbianControl checks this flag before doing Qt window
+    // resize due to status pane change.
+    // Eventually when layout is ready, Symbian framework calls
+    // HandleResourceChangeL(KEikDynamicLayoutVariantSwitch) which triggers
+    // resize to Qt window and to its EGL surface. 
+    S60->handleStatusPaneResizeNotifications = false;
     QS60MainAppUiBase::HandleScreenDeviceChangedL();
+    S60->handleStatusPaneResizeNotifications = true;
 }
 
 /*!