3 files changed, 35 insertions, 12 deletions

diff --git a/src/quickwidgets/qquickwidget.cpp b/src/quickwidgets/qquickwidget.cpp
index a848774ae9..5755271fe1 100644
--- a/src/quickwidgets/qquickwidget.cpp
+++ b/src/quickwidgets/qquickwidget.cpp
@@ -39,8 +39,9 @@
 #include "private/qquickitemchangelistener_p.h"
 #include "private/qquickrendercontrol_p.h"
 
+#include <private/qqmldebugconnector_p.h>
 #include <private/qquickprofiler_p.h>
-#include <private/qqmlinspectorservice_p.h>
+#include <private/qqmldebugserviceinterfaces_p.h>
 #include <private/qqmlmemoryprofiler_p.h>
 
 #include <QtQml/qqmlengine.h>
@@ -95,8 +96,9 @@ void QQuickWidgetPrivate::init(QQmlEngine* e)
     if (!engine.data()->incubationController())
         engine.data()->setIncubationController(offscreenWindow->incubationController());
 
-    if (QQmlDebugService::isDebuggingEnabled())
-        QQmlInspectorService::instance()->addView(q);
+    QQmlInspectorService *service = QQmlDebugConnector::service<QQmlInspectorService>();
+    if (service)
+        service->addView(q);
 
 #ifndef QT_NO_DRAGANDDROP
     q->setAcceptDrops(true);
@@ -142,13 +144,15 @@ QQuickWidgetPrivate::QQuickWidgetPrivate()
     , eventPending(false)
     , updatePending(false)
     , fakeHidden(false)
+    , requestedSamples(0)
 {
 }
 
 QQuickWidgetPrivate::~QQuickWidgetPrivate()
 {
-    if (QQmlDebugService::isDebuggingEnabled())
-        QQmlInspectorService::instance()->removeView(q_func());
+    QQmlInspectorService *service = QQmlDebugConnector::service<QQmlInspectorService>();
+    if (service)
+        service->removeView(q_func());
 
     invalidateRenderControl();
 
@@ -538,6 +542,9 @@ QQuickWidget::Status QQuickWidget::status() const
     if (!d->component)
         return QQuickWidget::Null;
 
+    if (d->component->status() == QQmlComponent::Ready && !d->root)
+        return QQuickWidget::Error;
+
     return QQuickWidget::Status(d->component->status());
 }
 
@@ -559,6 +566,10 @@ QList<QQmlError> QQuickWidget::errors() const
         QQmlError error;
         error.setDescription(QLatin1String("QQuickWidget: invalid qml engine."));
         errs << error;
+    } else if (d->component->status() == QQmlComponent::Ready && !d->root) {
+        QQmlError error;
+        error.setDescription(QLatin1String("QQuickWidget: invalid root object."));
+        errs << error;
     }
 
     return errs;
@@ -764,7 +775,7 @@ void QQuickWidget::createFramebufferObject()
 
     context->makeCurrent(d->offscreenSurface);
 
-    int samples = d->offscreenWindow->requestedFormat().samples();
+    int samples = d->requestedSamples;
     if (!QOpenGLExtensions(context).hasOpenGLExtension(QOpenGLExtensions::FramebufferMultisample))
         samples = 0;
 
@@ -878,14 +889,15 @@ void QQuickWidgetPrivate::setRootObject(QObject *obj)
     if (QQuickItem *sgItem = qobject_cast<QQuickItem *>(obj)) {
         root = sgItem;
         sgItem->setParentItem(offscreenWindow->contentItem());
+    } else if (qobject_cast<QWindow *>(obj)) {
+        qWarning() << "QQuickWidget does not support using windows as a root item." << endl
+                   << endl
+                   << "If you wish to create your root window from QML, consider using QQmlApplicationEngine instead." << endl;
     } else {
         qWarning() << "QQuickWidget only supports loading of root objects that derive from QQuickItem." << endl
                    << endl
-                   << "If your example is using QML 2, (such as qmlscene) and the .qml file you" << endl
-                   << "loaded has 'import QtQuick 1.0' or 'import Qt 4.7', this error will occur." << endl
-                   << endl
-                   << "To load files with 'import QtQuick 1.0' or 'import Qt 4.7', use the" << endl
-                   << "QDeclarativeView class in the Qt Quick 1 module." << endl;
+                   << "Ensure your QML code is written for QtQuick 2, and uses a root that is or" << endl
+                   << "inherits from QtQuick's Item (not a Timer, QtObject, etc)." << endl;
         delete obj;
         root = 0;
     }
@@ -1239,6 +1251,14 @@ void QQuickWidget::setFormat(const QSurfaceFormat &format)
     newFormat.setDepthBufferSize(qMax(newFormat.depthBufferSize(), currentFormat.depthBufferSize()));
     newFormat.setStencilBufferSize(qMax(newFormat.stencilBufferSize(), currentFormat.stencilBufferSize()));
     newFormat.setAlphaBufferSize(qMax(newFormat.alphaBufferSize(), currentFormat.alphaBufferSize()));
+
+    // Do not include the sample count. Requesting a multisampled context is not necessary
+    // since we render into an FBO, never to an actual surface. What's more, attempting to
+    // create a pbuffer with a multisampled config crashes certain implementations. Just
+    // avoid the entire hassle, the result is the same.
+    d->requestedSamples = newFormat.samples();
+    newFormat.setSamples(0);
+
     d->offscreenWindow->setFormat(newFormat);
 }
 
diff --git a/src/quickwidgets/qquickwidget.h b/src/quickwidgets/qquickwidget.h
index a8bf03edfb..5bb6b49a49 100644
--- a/src/quickwidgets/qquickwidget.h
+++ b/src/quickwidgets/qquickwidget.h
@@ -56,7 +56,6 @@ class Q_QUICKWIDGETS_EXPORT QQuickWidget : public QWidget
     Q_PROPERTY(ResizeMode resizeMode READ resizeMode WRITE setResizeMode)
     Q_PROPERTY(Status status READ status NOTIFY statusChanged)
     Q_PROPERTY(QUrl source READ source WRITE setSource DESIGNABLE true)
-    Q_ENUMS(ResizeMode Status)
 
 public:
     explicit QQuickWidget(QWidget *parent = 0);
@@ -72,10 +71,12 @@ public:
     QQuickItem *rootObject() const;
 
     enum ResizeMode { SizeViewToRootObject, SizeRootObjectToView };
+    Q_ENUM(ResizeMode)
     ResizeMode resizeMode() const;
     void setResizeMode(ResizeMode);
 
     enum Status { Null, Ready, Loading, Error };
+    Q_ENUM(Status)
     Status status() const;
 
     QList<QQmlError> errors() const;
diff --git a/src/quickwidgets/qquickwidget_p.h b/src/quickwidgets/qquickwidget_p.h
index e8d1f714f3..fa8bb3beb7 100644
--- a/src/quickwidgets/qquickwidget_p.h
+++ b/src/quickwidgets/qquickwidget_p.h
@@ -115,6 +115,8 @@ public:
     bool eventPending;
     bool updatePending;
     bool fakeHidden;
+
+    int requestedSamples;
 };
 
 QT_END_NAMESPACE