arrow.h

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#ifndef ARROW_H
#define ARROW_H

#include <QGraphicsLineItem>

#include "diagramitem.h"

QT_BEGIN_NAMESPACE
class QGraphicsPolygonItem;
class QGraphicsLineItem;
class QGraphicsScene;
class QRectF;
class QGraphicsSceneMouseEvent;
class QPainterPath;
QT_END_NAMESPACE

//! [0]
class Arrow : public QGraphicsLineItem
{
public:
    enum { Type = UserType + 4 };

    Arrow(DiagramItem *startItem, DiagramItem *endItem,
      QGraphicsItem *parent = 0);

    int type() const override { return Type; }
    QRectF boundingRect() const override;
    QPainterPath shape() const override;
    void setColor(const QColor &color) { myColor = color; }
    DiagramItem *startItem() const { return myStartItem; }
    DiagramItem *endItem() const { return myEndItem; }
    bool operator==(Arrow &arrow);

    void updatePosition();

protected:
    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget = 0) override;

private:
    DiagramItem *myStartItem;
    DiagramItem *myEndItem;
    QColor myColor;

    QPolygonF arrowHead;
};
//! [0]

#endif // ARROW_H