hi you are right - I want to change parameters according to x/y changes.
I will have a look at you solution too! And come back of course.

Either I subclass QGraphicsScene - as you wrote before or using an event filter might help. I found this thread about it.
https://stackoverflow.com/questions/51151806/use-a-qgraphicsscenemouseevent-in-a-class-that-inherits-from-qgraphicsview

bool DisplayImage::eventFilter(QObject *watched, QEvent *event)
{
    if(watched == scene){
        // press event
        QGraphicsSceneMouseEvent *mouseSceneEvent;
        if(event->type() == QEvent::GraphicsSceneMousePress){
            mouseSceneEvent = static_cast<QGraphicsSceneMouseEvent *>(event);
            qDebug()<<mouseSceneEvent->scenePos()<<mouseSceneEvent->lastScenePos();
           // your logic here
        }
        // move event
        else if (event->type() == QEvent::GraphicsSceneMouseMove) {
            mouseSceneEvent = static_cast<QGraphicsSceneMouseEvent *>(event);
            qDebug()<<mouseSceneEvent->scenePos()<<mouseSceneEvent->lastScenePos();
            // your logic here
        }
        // release event
        else if (event->type() == QEvent::GraphicsSceneMouseRelease) {
            mouseSceneEvent = static_cast<QGraphicsSceneMouseEvent *>(event);
            qDebug()<<mouseSceneEvent->scenePos()<<mouseSceneEvent->lastScenePos();
            // your logic here
        }
    }
    return QGraphicsView::eventFilter(watched, event);
}

error: non-virtual member function marked 'override' hides virtual member function
Honestly I have never understood when I can override a QT function and when I can't.

This is totally a C++ issue, nothing special about Qt. And it is really easy to tell:

• If a method is marked virtual you can override it. And Qt docs will always show virtual for such methods.
• If a method is not marked virtual you cannot override it.

"Simplez" :) override is not mandatory, but I suggest you should always put it in if you are intending to override a method. Because you get an error then if the method, or its signature, are not virtual/overridable, and you will know. And in this case the error message tells you exactly that.

So you must either sub-class your QGraphicsScene and override its void mouseMoveEvent(QGraphicsSceneMouseEvent *mouseEvent) (which I have never tried) or you need to override the QGraphicsView::mouseMoveEvent(QMouseEvent *event) in your WpEditor. In this case, confirm that you will keep the left mouse pressed down while you do drag-move, else you will need to call QGraphicsView::setMouseTracking(true) .

Meanwhile, I noticed your original QGraphicsScene::mouseMoveEvent(event); in WpEditor::mouseMoveEvent(), your attempt to call the base class implementation. I took you at your word, but you need QGraphicsView::mouseMoveEvent(event); instead!

error: non-virtual member function marked 'override' hides virtual member function

Show the code. You're not correctly overriding.

@ademmler

Dear JonB - thx for your feedback.

You mean your method is not hit? Start by appending override in the .h file to be sure.

When I do so I get:
error: non-virtual member function marked 'override' hides virtual member function
Honestly I have never understood when I can override a QT function and when I can't.

WpEditoris indeed aQGraphicsSceneand not aQGraphicsView`, right?

It is a QGrahicsview (in an UI file) which I attache a scene to. In the constructor I do:
... some stuff
sceneWp = new QGraphicsScene(0, 0, 500, 500);
viewWp->setScene(sceneWp);
... some more stuff

In the event I think you will want to use event->scenePos(); rather than event->pos();.

Yes this is correct - my fault !

void WpEditor::mouseMoveEvent(QGraphicsSceneMouseEvent *event)

What is your WpEditor class a sub-class of?

WpEditor is indeed a QGraphicsScene and not a QGraphicsView, right?

In the event I think you will want to use event->scenePos(); rather than event->pos();.