using a QRubberBand on top of a QGraphicsItem

Question

I am trying to make it so that if a user clicks on a QGraphicsItem it will make a QRubberBand for just that item.

I have the following in my class:

void ImagePixmapItem::mousePressEvent(QGraphicsSceneMouseEvent *event){
    if(currentKey == Qt::Key_Control){
        qDebug("This is a control click");

        origin = event->screenPos();
        if (!selected.isNull())
            selected = new QRubberBand(QRubberBand::Rectangle, event->widget());
        selected->setGeometry(QRect(origin, QSize()));
        selected->show();

    }
}

This is giving me an error on the setGeometry call, but no additional information. This was essentially code I got from QRubberBand, except that I had to use event.screePos() and I had to set the constructor of QRubberBand to event.widget() instead of "this" because, I think, QGraphicsItem does not inherit from QWidget?

Is there a better way of doing this?

Thanks

Answer 1

I made this example, I hope to help

My custom item.

#ifndef ITEM_H
#define ITEM_H
#include <QtCore>
#include <QtGui>
class Item : public QGraphicsRectItem
{
public:
    Item()
    {
        setRect(0,0,100,100);
    }

    void mousePressEvent(QGraphicsSceneMouseEvent * event)
    {
        origin = event->screenPos();
        if (!rubberBand)
            rubberBand = new QRubberBand(QRubberBand::Rectangle,0);
        rubberBand->setGeometry(QRect(origin, QSize()));
        rubberBand->show();
    }

    void mouseMoveEvent(QGraphicsSceneMouseEvent * event )
    {
        QRectF inside = QGraphicsRectItem::boundingRect();
        QPointF mapPoint = mapFromScene(event->pos());
        if(inside.contains(mapPoint))
            rubberBand->setGeometry(QRect(origin, event->screenPos()).normalized());
    }

    void mouseReleaseEvent(QGraphicsSceneMouseEvent * event )
    {
        rubberBand->hide();

    }
private:
    QRubberBand * rubberBand;
    QPoint origin;

};

#endif // ITEM_H

and show the view

#include <QtGui>
#include "item.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QGraphicsView w;
    QGraphicsScene s;
    Item * item = new Item();
    w.setScene(&s);
    s.addItem(item);

    w.show();
    return a.exec();
}