QWT oscilloscope example help



  • QWT oscilloscope example - wheelbox.cpp. Please see code bellow. I could not understand that. That means that whenever I scroll the
    mouse it will, generate QEvent::Wheel, then event will be modified only with QPoint( 5, 5 )
    (possibly to put mouse on 5,5 coordinate? After the event will be sent to this object which is Wheel class instance? Why?

    virtual bool eventFilter( QObject *object, QEvent *event )

    {
    
        if ( event->type() == QEvent::Wheel )
    
        {
    
            QWheelEvent *we = ( QWheelEvent * )event
    
            QWheelEvent wheelEvent( QPoint( 5, 5 ), we->delta(),
    
                we->buttons(), we->modifiers(),
    
                we->orientation() );
    
            QApplication::sendEvent( this, &wheelEvent );
    
            return true;
    
        }
    
        return QwtWheel::eventFilter( object, event );
    }
    

    };



  • Exactly, why we have to include this:

    QWheelEvent wheelEvent( QPoint( 5, 5 ), we->delta(),

                we->buttons(), we->modifiers(),
    
                we->orientation() );
    

    QPoint( 5, 5 ) is pos or global pos?

    What is pixelDelta? What does mean that it contains the scrolling distance in pixels
    on screen?


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