Is it possible to easily modify individual pixels displayed on a screen according to a function? For example, suppose a pixel on the screen had values in (Red,Green,Blue) = (25,50,100) and I want to replace that pixel by the ones (f1(50),f2(100),f3(150)) = (50,100,200).
Hopefully this function should be the last one in the "pipeline" of screen modifiers, so every pixel gets changed correctly.
The objective was to write a small program to alleviate colorblind issues with some knowledge of color theory I just learned. My knowledge of how I would go about actually programming it is very low however.