QGraphicsProxyWidget > Qlabel get mouseMove/Release events?

  • Hey

    I'm trying to get an event response from my QLabel that is set to be QGraphicsProxyWidget.

    In my QGraphicsView I set

    void test::mouseMoveEvent(QMouseEvent *event){

    But no matter what I do, I cant get the events to show up in proxyWidget or QLabel itself. How can I forward them to the correct widget? The GraphicsView event dont match with QGraphicsSceneMouseEvent so I'm bit lost ?


  • Qt Champions 2017

    Normally the widget that are inserted into the proxy just works.

    See this small sample

    #include <QGraphicsProxyWidget>
    #include <QGraphicsScene>
    #include <QGraphicsView>
    #include <QMessageBox>
    #include <QPushButton>
    #include <QDebug>
    int main(int argc, char** argv) {
      QApplication app(argc, argv);
      QPushButton* button = new QPushButton("CLICK ME");
      QObject::connect(button, &QPushButton::clicked, [ = ]() {
        QMessageBox::warning(0, "Hello from widget", "Im alive");
      } );
      QGraphicsScene scene;
      QGraphicsProxyWidget* proxy = scene.addWidget(button);
      QGraphicsView view(&scene);
      return app.exec();

    alt text

    Do you put them in an qgraphicsitemgroup ?

    Also , normally a QLabel do not have any mousePressEvent override so i assume you use something like https://wiki.qt.io/Clickable_QLabel
    to make it clickable. ?

  • Hey
    Mmmm tricky. I realized I did not need to use proxyWiwdget but QGraphicsPixmapItem was sufficient. So I stayed at View level and handled it all from there for now, but I'm still puzzled.

    Say you have

    QGraphicsPixmapItem and you click on it and do mouse move. Would I like to forward the event from QGraphicsView to QGraphicsPixmapItem as that does not happen as standard? How can I do that? I think that View by default would attempt to move the item in the scene. But I don't want to do this. I just want to pass press/move/release events to the underlying item.

  • Qt Champions 2017

    Can we talk about what goal is ?
    If you think QGraphicsPixmapItem is what you need i guess that you first
    tried to show pixmap in a QLabel.
    Since the pixmap have no methods for handling any input in not really sure
    why you try to forward events to it.

    Are you trying to make a clickable image or what is the overall goal ?
    If yes, please see this

  • The more I think of it the less I want to forward events to it actually... well maybe not. I want to have different items and then change their event behavior based on their types. So I thought I could forward it to them. Lets say I have a list view, I would like to forward mouseWheelEvent scroll to it when mouse is over the widget. Same goes for QImage/Pixmap I wanted to try some paint effect where I could paint on image in QGraphicsView so I can move it around anywhere/etc/etc.

  • Qt Champions 2017

    If you want special items, i suggest you just create your own classes by subclassing
    QGraphicsItem. That way you can make them do whatever you like.

    Your example with ListView should work already as far as i know it can scroll with mouse3 but that needs a QGraphicsProxyWidget to function.

    As far as i know, one should use Proxy if you insert Widgets in the scene for them to fully function.

Log in to reply

Looks like your connection to Qt Forum was lost, please wait while we try to reconnect.