title: Is it possible to create full screen color overlay effects in windows?
body: <p>I remember my old Radeon graphics drivers which had a number of overlay effects or color filters (whatever they are called) that would render the screen in e.g. sepia tones or negative colors. My current NVIDIA card does not seem to have such a function so I wondered if it is possible to make my own for Vista.</p>
  
  <p>I don't know if there is some way to hook into window's rendering engine or, alternatively, into NVIDIA's drivers to achieve this effect. While it would be cool to just be able to modify the color, it would be even better to modify the color based on its screen coordinates or perform other more varied functions. An example would be colors which are more desaturated the longer they are from the center of the screen.</p>
  
  <p>I don't have a specific use scenario so I cannot provide much more information. Basically, I'm just curious if there is anything to work with in this area.</p>