Image capture prevention is mostly discussed from a different perspective : someone wants to make a web page with images that visitors can see, but cannot save (which is much harder and considered impossible).
There is an easier task - prevent screen capture using Windows tools while an app is running.
Starcraft 2 game blocks screen capture by ctrl-PrintScreen or third party tools. All you get is a black rectangle. It does have its own utility for screen capture, but it freezes the game for a second. This is probably done to discourage task scripting based on visual cues.
How can this be achieved? Do they add a listener to CreateCompatibleBitmap, when called ask for caller id and if caller is not Starcraft - send null?
