diff options
Diffstat (limited to 'src/plugins/platforms/ios/qiosviewcontroller.mm')
| -rw-r--r-- | src/plugins/platforms/ios/qiosviewcontroller.mm | 20 |
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]]) |