QQuickWidget: handle hide and show events properly

Task-number: QTBUG-37062
Change-Id: I3763385168eaa0ccd009ada563f56ea0251029a5
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>

3 files changed, 34 insertions, 4 deletions

diff --git a/src/quick/items/qquickrendercontrol.cpp b/src/quick/items/qquickrendercontrol.cpp
index faee1358ae..16ed6f0e10 100644
--- a/src/quick/items/qquickrendercontrol.cpp
+++ b/src/quick/items/qquickrendercontrol.cpp
@@ -162,6 +162,26 @@ bool QQuickRenderControl::sync()
 }
 
 /*!
+  Stop rendering and release resources. This function is typically
+  called when the window is hidden. Requires a current context.
+ */
+void QQuickRenderControl::stop()
+{
+    Q_D(QQuickRenderControl);
+    if (!d->window)
+        return;
+
+    QQuickWindowPrivate *cd = QQuickWindowPrivate::get(d->window);
+    cd->fireAboutToStop();
+    cd->cleanupNodesOnShutdown();
+
+    if (!cd->persistentSceneGraph) {
+        d->rc->invalidate();
+        QCoreApplication::sendPostedEvents(0, QEvent::DeferredDelete);
+    }
+}
+
+/*!
   Render the scenegraph using the current context.
  */
 void QQuickRenderControl::render()
diff --git a/src/quick/items/qquickrendercontrol_p.h b/src/quick/items/qquickrendercontrol_p.h
index 7255a9ae0b..98dc946303 100644
--- a/src/quick/items/qquickrendercontrol_p.h
+++ b/src/quick/items/qquickrendercontrol_p.h
@@ -71,6 +71,7 @@ public:
     void polishItems();
     void render();
     bool sync();
+    void stop();
 
     QImage grab();
 
diff --git a/src/quickwidgets/qquickwidget.cpp b/src/quickwidgets/qquickwidget.cpp
index d530e0c18f..147762c66f 100644
--- a/src/quickwidgets/qquickwidget.cpp
+++ b/src/quickwidgets/qquickwidget.cpp
@@ -769,18 +769,27 @@ void QQuickWidget::mouseDoubleClickEvent(QMouseEvent *e)
     d->offscreenWindow->mouseDoubleClickEvent(&mappedEvent);
 }
 
-void QQuickWidget::showEvent(QShowEvent *e)
+void QQuickWidget::showEvent(QShowEvent *)
 {
     Q_D(QQuickWidget);
     QQuickWindowPrivate::get(d->offscreenWindow)->forceRendering = true;
-    d->offscreenWindow->showEvent(e);
+
+    d->updatePending = false;
+    triggerUpdate();
 }
 
-void QQuickWidget::hideEvent(QHideEvent *e)
+void QQuickWidget::hideEvent(QHideEvent *)
 {
     Q_D(QQuickWidget);
     QQuickWindowPrivate::get(d->offscreenWindow)->forceRendering = false;
-    d->offscreenWindow->hideEvent(e);
+
+    QOpenGLContext *context = d->offscreenWindow->openglContext();
+    if (!context) {
+        qWarning("QQuickWidget::hideEvent with no context");
+        return;
+    }
+    context->makeCurrent(d->offscreenWindow);
+    d->renderControl->stop();
 }
 
 /*! \reimp */