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c++qtqgraphicssceneqgraphicsitem

Get QGraphicsItem by mouse position in QGraphicsScene

I am trying to connect two QGraphicsItems by straight line (QGraphicsLineItem); by clicking with middle mouse button on first object, then hover on second object and after I release it, it should draw line between them.

This is function that should connect these items.

void GraphicsBlock::connectBlocks(GraphicsBlock *block)
{
    GraphicsConnect *connection = new GraphicsConnect(); //Class with QGraphicsLineItem
    connection->line->setLine(QLineF(this->pos(), block->pos()));
}

I am working on one scene and I've got problem with finding second block by mouse position. Function mousePressEvent should work with this code:

if(event->button() == Qt::MiddleButton)
    Connecting == true;

and after that mouseReleaseEvent

if(Connecting)
{
    //Get object by mouse position here
    //this.connectBlocks(..)
    Connecting = false;
}

I tried scene->itemsAt(mouse.x(), mouse.y(), QTransform()) and

scene->items(QPointF(mouse.x(),mouse.y()) but it always returned empty list.

EDIT: This is how application should work, blue ellipse is clicked port, now i should drag (still mouse down) to another port and release mouse.

Application image

Solution

  • I solved this with

    QGraphicsItem *item = scene.itemAt(mapToScene(event->pos()), QTransform());

    in function mouseReleaseEvent