but adding "painter.repaint" did not make any diference.
It is painter.restore and not painter.repaint

I will try to send a screen shotshot, but I don't knowif this is the way to do it.
[IMG]/home/pete/Programs/pmProgram/snapshot6.png[/IMG]
You can upload your png at http://imageshack.us and then give the link here like:

[IMG]link[/IMG]

Say I want to paint the lines without the labels. Is the procedure I have used here appropiate?
I think its fine. But you will need to call repaint() in order to see changes immediately.