how to paint on child widgets in qt4.5

[Hsv]

I written a code in QT(4.5) to draw or paint a circle on parent widget.
The code is like this.

void frmdemo:aintEvent (QPaintEvent *)
{

QPainter paint(this);

paint.setPen(red);
paint.setBrush(Qt::green);
paint.drawEllipse(10, 400, 25, 25);

}

The above code will paint a circle on parent widget.

But if i want to draw a circle on tabwidget, ie on child widget because tabwidget is lies on parent widget. The code is like this.

void frmdemo:aintEvent (QPaintEvent *)
{

QPainter paint(tabplot);

paint.setPen(red);
paint.setBrush(Qt::green);
paint.drawEllipse(10, 400, 25, 25);

}

The above code will not paint a circle on tabwidget named as tabplot. This code will work in qt3.1, but not in qt4.5.
After executing the pgm, the message will come in terminal window as widget painting only begin as a paintevent.

how to paint a circle on child widget. please suggest me.

[tamhanna]

Know this eeker too well. You can only paint in a widget in its OWN paint event. So you need to call the repaint() of the widget, override the widget's repaint and to the work there.

New in Qt 4; I don't like it - but it has to be due to compatibility.

[axeljaeger]

What is the usecase of doing such things? I guess it will not work in other toolkits too. So I think there will be a clean solution in solving your problem when knowing the bigger picture.

[danhicksbyron]

Why don't you just create a new widget, position it over the child, and paint on that?