mygraphicsview.h

#include <QGraphicsView>
#include <QGraphicsScene>
#include <QGraphicsPixmapItem>
#include <QWheelEvent>
#include <QKeyEvent>

class MyGraphicsView : public QGraphicsView
{
    Q_OBJECT
public:
    MyGraphicsView(QWidget* parent = nullptr);
protected Q_SLOTS:
  void wheelEvent(QWheelEvent *event);
  void mousePressEvent(QMouseEvent *event);
  void mouseMoveEvent(QMouseEvent *event);
private:
  qreal m_originX, m_originY;
};