Clightd is a bus interface that lets you easily set screen brightness, gamma temperature and get ambient brightness through webcam frames capture or ALS devices.
For a guide on how to build, features and lots of other infos, refer to Clightd Wiki Pages.
For any other info, please feel free to open an issue.
Arch AUR packages
Clightd is available on AUR as both stable or devel package: https://aur.archlinux.org/packages/?K=clightd .
Note that devel package may break in some weird ways during development. Use it at your own risk.
This software is distributed with GPL license, see COPYING file for more informations.