Allow scrolling hand dragging for non interactive scenes.

--HG--
branch : develop

src/app/valentina/mainwindowsnogui.cpp

@@ -1116,7 +1116,8 @@ QList<QGraphicsScene *> MainWindowsNoGUI::CreateScenes(const QList<QGraphicsItem
     QList<QGraphicsScene *> scenes;
     for (int i=0; i<papers.size(); ++i)
     {
-        QGraphicsScene *scene = new VMainGraphicsScene();
+        auto *scene = new VMainGraphicsScene();
+        scene->SetNonInteractive(true);
         scene->setBackgroundBrush(QBrush(QColor(Qt::gray), Qt::SolidPattern));
         scene->addItem(shadows.at(i));
         scene->addItem(papers.at(i));

src/libs/vwidgets/vmaingraphicsscene.cpp

@@ -113,6 +113,18 @@ void VMainGraphicsScene::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
     QGraphicsScene::mouseReleaseEvent(event);
 }
 
+//---------------------------------------------------------------------------------------------------------------------
+bool VMainGraphicsScene::IsNonInteractive() const
+{
+    return m_nonInteractive;
+}
+
+//---------------------------------------------------------------------------------------------------------------------
+void VMainGraphicsScene::SetNonInteractive(bool nonInteractive)
+{
+    m_nonInteractive = nonInteractive;
+}
+
 //---------------------------------------------------------------------------------------------------------------------
 void VMainGraphicsScene::InitOrigins()
 {

src/libs/vwidgets/vmaingraphicsscene.h

@@ -63,6 +63,10 @@ public:
     QRectF        VisibleItemsBoundingRect() const;
     void          InitOrigins();
     void          SetOriginsVisible(bool visible);
+
+    bool          IsNonInteractive() const;
+    void          SetNonInteractive(bool nonInteractive);
+
 public slots:
     void          ChoosedItem(quint32 id, const SceneObject &type);
     void          SelectedItem(bool selected, quint32 object, quint32 tool);
@@ -145,6 +149,7 @@ signals:
     void          LanguageChanged();
 
 private:
+    Q_DISABLE_COPY(VMainGraphicsScene)
     /** @brief horScrollBar value horizontal scroll bar. */
     qint32        horScrollBar;
 
@@ -155,6 +160,9 @@ private:
     QTransform    _transform;
     QPointF       scenePos;
     QVector<QGraphicsItem *> origins;
+
+    /** @brief m_nonInteractive all item on scene in non interactive. */
+    bool          m_nonInteractive{false};
 };
 
 //---------------------------------------------------------------------------------------------------------------------

src/libs/vwidgets/vmaingraphicsview.cpp

@@ -568,9 +568,10 @@ void VMainGraphicsView::mousePressEvent(QMouseEvent *event)
         }
         case Qt::MiddleButton:
         {
+            auto scene = qobject_cast<VMainGraphicsScene*>(this->scene());
             const QList<QGraphicsItem *> list = items(event->pos());
-            if (list.size() == 0)
+            if (list.isEmpty() || (scene && scene->IsNonInteractive()))
-            {// Only when the user clicks on the scene background
+            {// Only when the user clicks on the scene background or non interactive scene
                 m_ptStartPos = event->pos();
                 m_oldCursor = viewport()->cursor();
                 QGraphicsView::setDragMode(QGraphicsView::ScrollHandDrag);