Need advice (GUI, widgets) - choosing an area on the site

(I am new to GUI programming, experienced programmer otherwise)

(Using wxPython, but general advice welcome)

I am looking for advice / guidance on implementing a widget that can do an area selection on a plot. Any pointers from experienced users would be much appreciated.

What should be done:

• Implement a 2D plot.
• Introduce a resizable square that you can move to select an area on the graph.
• Mark plot points that fall into this area.

I understand that given the coordinates of the square and a sorted list of plot points, the contained plot points are easy to calculate. I'm just not sure about the widgets / graphics techniques one needs to use to implement the plot itself and the size of the resizable square.

Thanks for any help!