iOS: implement requestWindowOrientation

The application is normally supposed to rotate the content on its
own, but can call requestWindowOrientation to ask the window
manager to do it instead. This way of integrating orientation with
the OS is fragile, because:
1. In some cases, you cannot stop the OS from rotating at all
    (tablets).
2. It would be more safe to inform the window manager up-front
    which orientations it could rotate into, rather that relying
    on a function you call call to force this later on.
3. When the QML application starts, its a bit late to inform
    the platform plugin that it supports e.g landscape. If the
    OS is in landscape already, the plugin must still assume that
    the app operates in portrait (doing rotating on its own) until
    requestWindowOrientation is called. This might cause the app
    to first start up in portrait, just to rotate into landscape.

On iOS, it seems like we can handle the first two cases. The third
need some more investigation. We should anyway investigate if we
need some adjustment to the Qt API.

Change-Id: I50638b78d469ab70820a787de86a2f1981470786
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@digia.com>

src/plugins/platforms/ios/qiosviewcontroller.h

@@ -40,7 +40,13 @@
 ****************************************************************************/
 
 #import <UIKit/UIKit.h>
+#import <QtCore/qnamespace.h>
 
-@interface QIOSViewController : UIViewController
+@interface QIOSViewController : UIViewController {
+@public
+    bool m_shouldAutorotate;
+}
+
+-(bool)rotateToDeviceOrientation;
 @end
 

src/plugins/platforms/ios/qiosviewcontroller.mm

@@ -43,12 +43,32 @@
 
 @implementation QIOSViewController
 
-- (BOOL)shouldAutorotate
+-(id)init
 {
-    return NO;
+    self = [super init];
+    if (self) {
+        m_shouldAutorotate = NO;
+    }
+    return self;
 }
 
-- (NSUInteger)supportedInterfaceOrientations
+-(bool)rotateToDeviceOrientation
+{
+    if ([UIViewController respondsToSelector:@selector(attemptRotationToDeviceOrientation)]) {
+        m_shouldAutorotate = YES;
+        [UIViewController attemptRotationToDeviceOrientation];
+        m_shouldAutorotate = NO;
+        return true;
+    }
+    return false;
+}
+
+-(BOOL)shouldAutorotate
+{
+    return m_shouldAutorotate;
+}
+
+-(NSUInteger)supportedInterfaceOrientations
 {
     // We need to tell iOS that we support all orientations in order to set
     // status bar orientation when application content orientation changes.

src/plugins/platforms/ios/qioswindow.h

@@ -87,6 +87,7 @@ public:
 
     void setWindowState(Qt::WindowState state);
     void handleContentOrientationChange(Qt::ScreenOrientation orientation);
+    Qt::ScreenOrientation requestWindowOrientation(Qt::ScreenOrientation orientation);
 
     GLuint framebufferObject(const QIOSContext &context) const;
 

src/plugins/platforms/ios/qioswindow.mm

@@ -44,6 +44,7 @@
 #include "qiosscreen.h"
 #include "qiosapplicationdelegate.h"
 #include "qiosorientationlistener.h"
+#include "qiosviewcontroller.h"
 
 #import <QuartzCore/CAEAGLLayer.h>
 
@@ -257,6 +258,22 @@ void QIOSWindow::handleContentOrientationChange(Qt::ScreenOrientation orientatio
     [[UIApplication sharedApplication] setStatusBarOrientation:uiOrientation animated:NO];
 }
 
+Qt::ScreenOrientation QIOSWindow::requestWindowOrientation(Qt::ScreenOrientation orientation)
+{
+    if (!m_view.window)
+        return Qt::PortraitOrientation;
+    UIViewController *viewController = m_view.window.rootViewController;
+    if (!viewController || [viewController isKindOfClass:[QIOSViewController class]] == false) {
+        return convertToQtOrientation(viewController.interfaceOrientation);
+    } else {
+        QIOSViewController *qiosViewController = static_cast<QIOSViewController *>(viewController);
+        if ([qiosViewController rotateToDeviceOrientation])
+            return orientation;
+        else
+            return convertToQtOrientation(viewController.interfaceOrientation);
+    }
+}
+
 GLuint QIOSWindow::framebufferObject(const QIOSContext &context) const
 {
     static GLuint framebuffer = 0;