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QGraphicsScene::itemAt() not working properly

Time:03-24

I am trying to find out the QGraphicsItem under the mouse (when mouse hover over the item). For that I am using itemAt() method but itemAt() is not returning QGraphicsItem.
I tried this way:

bool myViewer::eventFilter(QObject *watched, QEvent *event)
{
    bool fEvent = false;
    switch(event->type())
    {
        case QEvent::MouseButtonPress:
        {....}
        case QEvent::MouseButtonRelease:
        {...}
        case QEvent::Enter:
        {
           QMouseEvent * mouseEvent = static_cast<QMouseEvent *>(event);
           qDebug()<<"Event points = "<< mouseEvent->pos(); // showing points properly
           QPointF po = _view->mapToScene(mouseEvent->pos());       
           
           QGraphicsRectItem* rItem = qgraphicsitem_cast<QGraphicsRectItem*>(_scene->itemAt(po,QTransform()));
           if(rItem)
           {
              // some logic
           }
        }
          return true;

       default:
           break;
    }
    return fEvent;

         

I tried with QGraphicsView::itemAt() also. But still it did not work.
Note: In both way following lines works fine.

 QMouseEvent * mouseEvent = static_cast<QMouseEvent *>(event);
 qDebug()<<"Event points = "<< mouseEvent->pos();     
 

Where am I wrong?

CodePudding user response:

May be you can try handling QEvent::GraphicsSceneMousePress

And then get the position as said below (pseudo code. Not tetsted.)

//Get the scene event object.
QGraphicsSceneMouseEvent* sceneEvent = dynamic_cast<QGraphicsSceneMouseEvent*>(qevent);

//From the scene event object get the scene position.
QPointF po = sceneEvent->scenePos();

Use that position to find the item.

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