I don’t like compiz because it is very slow on my computer but I miss to be able to invert the colors specially when I am in bed at night.
iker@x230:~$ sudo apt-get install xcalib iker@x230:~$ xcalib -invert -alter
Now how to add a keyboard shortcut for it on XFCE
Settings -> keyboard -> Aplication shortcuts
xcalib -invert -alter = Super + N