Hi
I made a module to do this. It took forever to get right and even now, it's not for the faint hearted. The elements I used were
Alpha blending to snap the window as an image
Rectangle to create the window
CaptureWindow to get the window from the rectangle.
I made 2 modules
Module 1 has a preset rectangle on a form and it snapshots that
Module 2 has a form with a cut out. You can move the firm anywhere on screen and whatever is in the window cutout is snapshot to an image (this is what the alpha blending is for)
So, yes it can be done and it can be quite versatile. I intend to make mine into a plugin for developers etc.
Thanks
Nigel