Everybody has seen them, those little creatures that look and act like they live inside your computer. If you’re interested in creating your own screenmate, here is a little program that I put together a couple of years ago that shows you how this can be done. In this specific example I used some API calls to set the region of a window.
A region determines the area within the window where the operating system permits drawing. The operating system does not display any portion of a window that lies outside of the window region. A timer takes care of animation. Using some VBA you can even have it notify you of incoming e-mail. Check out the included documentation for details.
There a several ways in which a screenmate can be implemented. If I would create a similar program again I’d probably use another technique, perhaps windows transparency. The Win32 assembly source code is included. The assembler used is masm32. Enjoy!