QGraphicsScene geometric centre

[Nadia]

It seems yes , e.g. lines.

painter->drawLine(0,widget->height(), 0, 0-(widget->height()/2));
    painter->drawLine(0-(widget->width()/2),0, (widget->width()/2), 0);

painter->drawLine(0,widget->height(), 0, 0-(widget->height()/2));
    painter->drawLine(0-(widget->width()/2),0, (widget->width()/2), 0);

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Plot p;
    //set (x,y) w and h relative to screen
    p.setGeometry(100, 100, 800, 600);
 
    p.show();

Plot p;
    //set (x,y) w and h relative to screen
    p.setGeometry(100, 100, 800, 600);

    p.show();

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but result is that they are painted somewhere around.....