Challenging Pixel Detection Question

I have a difficult problem and I am curious if it is possible and if so how one would go about doing it.

I am considering adding a function to a program that detects the color of pixels in a seperate application that is running.

Let me know if, one you think its possible, and if so how it would be done or a place to star looking.

Thanks,
-Patrick

Probably not worth the hassle. Unless you take a screenshot and save it to a bitmap in memory.