I want to toogle my screen colors (for example with keyboard shortcut) between normal and inverted+grayscale. xcalib -i -a does what I need to invert them, but does not seem to be capable for making them grayscale. The answer from https://unix.stackexchange.com/questions/125257/how-can-i-make-the-screen-black-and-white suggests that I need to change the configuration file, but how to make it as toggle?
The ideal behaviour for color changes should look like:
Bonus: To get it even more useful I would like to apply these color changes only for specific window (web browser, word processor, etc).
