Strange behavior of mouse events or QCursor::setPos() does not work

mrjbom

I am trying to lock the mouse in the widget, for this I constantly set the mouse position in the center of the widget, and to move the camera in my scene I use the virtual cursor position.

void MainOpenGLWidget::mousePressEvent(QMouseEvent* event)
{
    virtualMousePosition = this->rect().center();
    qInfo() << "press event:";
    qInfo() << "real mouse position:" << event->pos();
    qInfo() << "virtual mouse position:" << virtualMousePosition;
    setCursor(Qt::BlankCursor);
    QCursor::setPos(mapToGlobal(this->rect().center()));
    QMouseEvent eventCopy(event->type(), virtualMousePosition, event->button(), event->buttons(), event->modifiers());
    sceneManager->callMousePressEventHandler(eventCopy);
    QWidget::mousePressEvent(event);
}

void MainOpenGLWidget::mouseMoveEvent(QMouseEvent* event)
{
    //"Note that the returned value(event::button()) is always Qt::NoButton for mouse move events."

    if (event->buttons() & Qt::LeftButton && event->pos() != rect().center())
    {
        virtualMousePosition += (event->pos() - rect().center());
        qInfo() << "move event:";
        qInfo() << "real mouse position:" << event->pos();
        qInfo() << "virtual mouse position:" << virtualMousePosition;
        QMouseEvent eventCopy(event->type(), virtualMousePosition, event->button(), event->buttons(), event->modifiers());
        sceneManager->callMouseMoveEventHandler(eventCopy);
        QCursor::setPos(mapToGlobal(this->rect().center()));
    }
    QWidget::mouseMoveEvent(event);
}

So, what's the problem I'm facing?
I have two cases:

I click a button on the widget(I don't move the mouse at the time of clicking) and then start moving the mouse left and this is the output I get:

press event:
real mouse position: QPoint(504,308)
virtual mouse position: QPoint(359,340)
move event:
real mouse position: QPoint(358,340) <- All is fine, the mouse is in the center of the widget
virtual mouse position: QPoint(358,340)
move event:
real mouse position: QPoint(357,340)
virtual mouse position: QPoint(356,340)
move event:
real mouse position: QPoint(358,340)
virtual mouse position: QPoint(355,340)
move event:
real mouse position: QPoint(358,340)
virtual mouse position: QPoint(354,340)
move event:
real mouse position: QPoint(356,340)
virtual mouse position: QPoint(351,340)

I move the mouse to the left over the widget and press the mouse button while moving the mouse.
Here's the output I get:

press event:
real mouse position: QPoint(638,309)
virtual mouse position: QPoint(359,340)
move event:
real mouse position: QPoint(637,309) <- Something went wrong, my mouse cursor didn't move to the center of the widget!
virtual mouse position: QPoint(637,309)
move event:
real mouse position: QPoint(634,309)
virtual mouse position: QPoint(912,278)
move event:
real mouse position: QPoint(356,340)
virtual mouse position: QPoint(909,278)
move event:
real mouse position: QPoint(358,340)
virtual mouse position: QPoint(908,278)
move event:
real mouse position: QPoint(355,340)
virtual mouse position: QPoint(904,278)
move event:
real mouse position: QPoint(357,340)
virtual mouse position: QPoint(902,278)
move event:
real mouse position: QPoint(358,340)
virtual mouse position: QPoint(901,278)
move event:
real mouse position: QPoint(356,340)
virtual mouse position: QPoint(898,278)

It turns out that if I press the button while moving the mouse, the cursor is not placed in the center and I have problems.
How can I avoid this?

Kent-Dorfman

do you really want to pass the event to the parent after processing it in the override?

mrjbom

@Kent-Dorfman Even if I don't do it, I will face this problem.