Drawing to the screen above a full screen window?

Im working on a calculation tool for a game I play all the time that runs fullscreen, also known as starcraft. My eventual goal is to be able to run the game fullscreen then my program that would be running in the background would draw lines ON TOP of the starcraft screen in a bright color for various purposes. Ive seen this done before I just dont know the easiest most efficient way to achieve it? Direct x...some crazy thing ive never heard of? Input?
Topic archived. No new replies allowed.