graphicsview.h Example File

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 #pragma once
 #include <QGraphicsView>

 class GraphicsView : public QGraphicsView
 {
     Q_OBJECT

 public:
     GraphicsView(QGraphicsScene *scene = 0, QWidget *parent = 0);

     bool viewportEvent(QEvent *event);

 private:
     qreal totalScaleFactor;
 };