Newbie seeks direction

[Kent Tenney]

Howdy,

I want to implement some image manipulation features.

The first on my list is;

* draw a shape over an image and retrieve the corner coordinates
  of that shape.

 A basic usage would be to draw a rectangle, use it's coordinates
 to crop the image.

I would later like to extend this to allow creating polygons,
circles and ellipses, associating the sets of points with the image.

At this point I took code from
http://murl.se/11111
and listing 8.2 from the book, "A simple frame subclass"

Is this a reasonable starting point?

Any suggestions as to how to implement drawing shape
outlines over the image?

Any examples out there I should be studying?

Thanks,
Kent