[xmonad] Working on bind to change brightness/temp. Any suggestions?

I'm working on setting up a binding to set brightness/color temperature in a way similar to the program redshift does with randr. http://jonls.dk/redshift/ I'm just wondering if anyone has done anything similar or has any tips for me. Just a first look, I see redshift calling xcb_randr_set_crtc_gamma from #include <xcb/randr.h>, and I'm wondering how to do the equivalent in xmonad. I'm not familiar with xmonad sources, gonna start looking around there next. The specific behaviour I'm thinking of is to toggle a lowered brightness/temp for the current active window's monitor (and subsequently, whichever monitor that window is displayed in, or no monitor if it is not being displayed). Thanks, Ian Kelling