Merge remote-tracking branch 'origin/5.9' into 5.10

 Conflicts:
	.qmake.conf
	mkspecs/win32-g++/qmake.conf
	src/corelib/global/qglobal_p.h
	src/corelib/global/qoperatingsystemversion_p.h
	src/corelib/io/qfilesystemengine_win.cpp
	src/network/bearer/qbearerengine.cpp
	src/platformsupport/input/libinput/qlibinputpointer.cpp
	src/sql/doc/snippets/code/doc_src_sql-driver.cpp
	src/widgets/kernel/qwidget_p.h
	src/widgets/kernel/qwidgetwindow.cpp
	src/widgets/styles/qfusionstyle.cpp
	tests/auto/corelib/io/qfileinfo/tst_qfileinfo.cpp

Change-Id: I80e2722f481b12fff5d967c28f89208c0e9a1dd8

1 files changed, 20 insertions, 0 deletions

diff --git a/src/plugins/platforms/ios/qiosviewcontroller.mm b/src/plugins/platforms/ios/qiosviewcontroller.mm
index a7f1254064..a7663b9e94 100644
--- a/src/plugins/platforms/ios/qiosviewcontroller.mm
+++ b/src/plugins/platforms/ios/qiosviewcontroller.mm
@@ -156,6 +156,26 @@
 
 - (void)layoutSubviews
 {
+    if (QGuiApplication::applicationState() == Qt::ApplicationSuspended) {
+        // Despite the OpenGL ES Programming Guide telling us to avoid all
+        // use of OpenGL while in the background, iOS will perform its view
+        // snapshotting for the app switcher after the application has been
+        // backgrounded; once for each orientation. Presumably the expectation
+        // is that no rendering needs to be done to provide an alternate
+        // orientation snapshot, just relayouting of views. But in our case,
+        // or any non-stretchable content case such as a OpenGL based game,
+        // this is not true. Instead of continuing layout, which will send
+        // potentially expensive geometry changes (with isExposed false,
+        // since we're in the background), we short-circuit the snapshotting
+        // here. iOS will still use the latest rendered frame to create the
+        // application switcher thumbnail, but it will be based on the last
+        // active orientation of the application.
+        QIOSScreen *screen = self.qtViewController->m_screen;
+        qCDebug(lcQpaWindow) << "ignoring layout of subviews while suspended,"
+            << "likely system snapshot of" << screen->screen()->primaryOrientation();
+        return;
+    }
+
     for (int i = int(self.subviews.count) - 1; i >= 0; --i) {
         UIView *view = static_cast<UIView *>([self.subviews objectAtIndex:i]);
         if (![view isKindOfClass:[QUIView class]])