itemChange not called

Bert59

Hi,

I have a rectangle I would like to keep inside the plot area as shown below.

To do so I have reimplemented QGraphicsRectItem as below:

CallOut::CallOut(QRectF rect, QRectF plotArea) :
    QGraphicsRectItem(rect),
    m_plotArea(plotArea)
{
}

QVariant CallOut::itemChange(QGraphicsItem::GraphicsItemChange change, const QVariant &value)
{
    if (change == ItemPositionChange) {
        // value is the new position.
        QPointF newPos = value.toPointF();

        if (!m_plotArea.contains(newPos)) {
           newPos.setX(qMin(m_plotArea.right(), qMax(newPos.x(), m_plotArea.left())));
            newPos.setY(qMin(m_plotArea.bottom(), qMax(newPos.y(), m_plotArea.top())));
            return newPos;
        }
        qDebug() << "ItemPositionChange";
    }
    qDebug() << "itemChange";

    return QGraphicsItem::itemChange(change, value);
}

Then I implement my rectangle as follows:

testRect = new CallOut(QRectF(0, 0, 100, 100), plotArea);
testRect->setFlag(QGraphicsItem::ItemIsMovable);
scene->addItem(testRect);

The issue is that itemChange is never called when I move the rectangle?

What did I made wrong?

mrjj

Hi,
To avoid massive change notifications, there are not all reported as default.
So i think you need
testRect->setFlag(QGraphicsItem::ItemSendsScenePositionChanges);

Bert59

@mrjj
Thank you, I forgot this important "detail".