Clight will set your screen backlight level by capturing frames from webcam and computing ambient brightness; it can manage your screen gamma temperature too. It uses geoclue2 to retrieve user location, and will compute sunrise/sunset times to set gamma.

It depends on a Bus interface i developed together with it, Clightd. Clightd is responsible of setting/getting screen brightness, capture frames from webcam and returning their average brightness, and setting/getting gamma. As it uses libudev to get/set backlight/get video device, it is much less prone to mistakes than "fopen/fscanf/fprintf", and safer.

Both softwares are distributed with a GPL license.

For more informations, please refer to both projects READMEs. I hope someone will find them interesting and useful!