thanks munn, but I am still in the learning phase and I want to do things the Qt4 way which is the reason for rewriting the program.

I understand what triggers a mouseEvent or a keypressEvent, but I don't know what triggers a paint Event.

I look at the "circle" example, but I don't see the event that acttvates the paintEvent.

I guess I am sort of looking for a "SIGNAL" but I know there isn't one per se. The best I can explain my understanding is, these event handlers monitor program activity and when somthing happens they like, they jump in and do their thing.

In my program I get user input of a set of coordinates for a line. The input is in string form. I attach this string to a QStringList. Now I want to display all, some, or just one of these lines in a "ui.drawingBox" ( a QFrame In designer ).I know I can extract the numeric coordinates, scale them either in a program module or in a paint Event. But what has to happen for the paintEvent to go into action?

What I tried to show in my last post was a simple program that had a drawing area (ui.drawingBox), QLineEdit, and 3 push buttons. "Draw", "Clear" & "Exit".
The "user" enters " 0, 0, 50, 75".,clicks on the "draw" button and the line is displyed on the screen.

If Trolltech would do somthing like this, a simple example for each of their functions, it would make life much simplier.