How to generate artifitial mouse events?

[moridinbg]

I would like to post artifitial mouse events in QGraphicsScene.
I have an application that parses some data and should be able to generate mouse clicks and moves based on it. Sometimes there may be several events at the same time.

I tried createing a new QGraphicsSceneMouseEvent and then set the data fields (setButton(), setPos(), setButtonDownPos(), etc) and then post the event to the Scene, but nothing happens.

Should I set absolutley everything (setPos, setScenePos, setLastPos, setLastScenePos) or setting just the scene positions is enaugh?

[QbelcorT]

Hi,
I did this for 'keypress' events using QCoreApplication::sendEvent, you can send any events with this function. There is even a mousepressevent example in the function code.


QMouseEvent event(QEvent::MouseButtonPress, pos, 0, 0, 0);
QApplication::sendEvent(mainWindow, &event);

[moridinbg]

Yes, I have read it, but it is not working for me with QGraphicsScene.
I have a graphics item with reimplemented mousePressEvent, and I am outputting the event coordinates on click, so I know that it works with just clicking with the mouse.
But posting a new QGraphicsSceneMouseEvent (or justQMouseEvent) with the correct buttonDown and position coordinates does nothing.

QGraphicsScene::event() returns false with my manually posted events.

[QbelcorT]

Are you posting the event to the correct object? Please provide an example of how you are posting the event using this method.

[moridinbg]

I am posting it to the right object for sure. I derived a class from QGraphicsScene and reimplemented QGraphicsScene::event().
I am posting a custom event to the scene with the coordinates of the desired mouse click and unique id (as I said there may be several clicks at the same time).
In the derived event() implementation I am successfully capturing the custom event and create a new QGraphicsSceneMouseEvent with the coordinates, which I am then passing to the base QGraphicsScene::event() function.
That's where nothing happens.


bool MyScene::event(QEvent *event)
{
if(event->type() == QEvent::User)
{
qDebug() << "Received!";
QGraphicsSceneMouseEvent *click = new QGraphicsSceneMouseEvent();
click->setButton(Qt::LeftButton);
click->setScenePos(QPointF(((MyEvent *)event)->getX(), ((MyEvent *)event)->getY()));
click->setButtonDownScenePos(Qt::LeftButton, QPointF(((MyEvent *)event)->getX(), ((MyEvent *)event)->getY()));
click->setLastScenePos(QPointF(((MyEvent *)event)->getX(), (((MyEvent *)event)->getY())));
return QGraphicsScene::event(click);
}
else
return QGraphicsScene::event(event);
}

[QbelcorT]

I assume you have a QGraphicsView in which the scene is using as a view?
I am looking at the QGraphicsSceneMouseEvent and it says.. "When a QGraphicsView receives a QMouseEvent, it translates it to a QGraphicsSceneMouseEvent. The event is then forwarded to the QGraphicsScene associated with the view"
Make sure you are posting the 'artificial' event to your view (QWidget/QGraphicsView), your 'view' will then forward that 'artificial' event to your scene.
see QMouseEvent. Where is this "event->type() == QEvent::User" this user event being posted from? FYI.. be careful of that 'new' operator in the event handler, make sure you are freeing your memory somewhere logical.

[moridinbg]

I am creating the events in the MainWindow.
I have already tried to send the event to the view, but nothing happens again?!
I even set it to setInteractive(true) although it should be enabled by default.
The code is:


void MainWindow::click()
{
QMouseEvent click(QEvent::MouseButtonPress, QPoint(126,575), Qt::LeftButton, 0, 0);
click.setAccepted(true);
QCoreApplication::sendEvent(m_view, &click);
}


I am checking incoming events in the scene derived class and there are no QGraphicsSceneMouseEvents, unless I click with the mouse.

These are the scene and view initializations:


m_scene = new MyScene();
m_scene->setSceneRect(0, 0, 600, 600);
m_scene->setItemIndexMethod(QGraphicsScene::NoIndex);
m_scene->setBackgroundBrush(Qt::red);

m_view = new QGraphicsView(m_scene);
m_view->setRenderHint(QPainter::Antialiasing);
m_view->setCacheMode(QGraphicsView::CacheBackground);
m_view->setViewportUpdateMode(QGraphicsView::BoundingRectV iewportUpdate);
m_view->setInteractive(true);
m_view->show();