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Get the qgraphicsitem under the mouse

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Doug Hoppes

Trainee

  • "Doug Hoppes" started this thread

Posts: 39

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1

Monday, October 18th 2010, 4:02am

Get the qgraphicsitem under the mouse

Hi all,

I'm trying to use the mouse to move a qgraphicsitem (rectangle) in my scene. However, no matter what I do, the left click event doesn't seem to be received by the qgraphicsscene. Is there a way to determine what object is underneath the mouse, when it is clicked?

Doug

qlands

Beginner

Posts: 33

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2

Monday, October 18th 2010, 8:47am

Hi,

Your item must have some flags in order to move it in the scene for example:

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item->setFlag(QGraphicsItem::ItemIsMovable, true);
item->setFlag(QGraphicsItem::ItemIsSelectable, true);


to determine what object is underneath the mouse, you need to subclass the scene and reimplement the mousePressEvent, for example:

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void myscene::mousePressEvent(QGraphicsSceneMouseEvent *mouseEvent)
{
  QGraphicsScene::mousePressEvent(mouseEvent); //Call the ancestor
  
  QGraphicsItem *item;
   item = itemAt(mouseEvent->scenePos()); //Get the item at the position
   if (item) //If there is an item at that position
   {
     //Some code
   }
}