fluxgui : f.lux indicator applet is an indicator applet to control xflux, an application that makes the color of your computer’s display adapt to the time of day, warm at nights and like sunlight during the day ( http://justgetflux.com/ https://github.com/Kilian/f.lux-indicator-applet )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a and3k-sunrise
For Paludis use this rsync : rsync://gentoo.zugaina.org/and3k-sunrise-portage
If you have a problem : ycarus(-at-)zugaina.org