Interactive graphics in Qt

Our customer would like to be able to interact with a displayed x-y plot with an overlaid grid by selecting two points within the grid, resulting in a line drawn to connect those points. Alternatively, two points could already exist with a line drawn between them and the user would like to be able to interactively move the two points around and have that line be refreshed "live".

It has been quite some time since I've used Qt although I did a project last year with Qt 4.6 and Qt Creator to build an app. I don't see any "x-y plot" widgets (so to speak) in the new Qt Creator 2.0.1 and so it seems I will have to build this from the ground up. Is there a Qt expert out there that can point me in the right direction with this request? Are there any tutorials on building interactive line plots with Qt? I can't seem to find any.

Thanks very much for your help!

There is Qwt:
http://qwt.sourceforge.net/

But if you want to build your own widgets from scratch, there are two techniques I would try: graphicsview or qml

I have looked at Qwt and their site. But I am not seeing anything on mouse-interactive graphics.. Can you verify that Qwt supports mouse-interactive graphical capabilities?