Clight is a C daemon utility to automagically change screen backlight level to match ambient brightness.
Ambient brightness is computed by capturing frames from webcam.
Moreover, it can manage your screen temperature, just like redshift does.
It was heavily inspired by calise in its initial intents.
- libxcb (xcb.h, xcb/dpms.h)
- libsystemd >= 221 (systemd/sd-bus.h)
- libpopt (popt.h)
- libconfig (libconfig.h)
- shared objects from build libraries
- clightd
Even if a systemd user unit is shipped, proper way to start clight is to put into your DE session autostart manager/X autostart script:
$ systemctl --user start clight.service
This is needed to assure that X is running when clight gets started.
On systemd there is no proper way of knowing whether X has been started or not.
Simply enabling the unit could cause clight to auto-disabling gamma support if it cannot find any running X server.
Note that is better to use that command to start the user service instead of just using "clight", because the service kicks in clightd dependency.
Moreover, it will make clight restart if any issue happens.
- very lightweight
- fully valgrind and cppcheck clean
- external signals catching (sigint/sigterm)
- systemd user unit shipped
- dpms support: it will check current screen powersave level and won't do anything if screen is currently off
- a quick single capture mode (ie: do captures, change screen brightness and leave)
- gamma support: it will compute sunset and sunrise and will automagically change screen temperature (just like redshift does)
- geoclue2 support: when launched without [--lat|--lon] parameters, if geoclue2 is available, it will use it to get user location updates
- different nightly and daily captures timeout (by default 45mins during the night and 10mins during the day; both configurable)
- nice log file, placed in $HOME/.clight.log
- --sunrise/--sunset times user-specified support: gamma nightly temp will be setted at sunset time, daily temp at sunrise time
- more frequent captures inside "events": an event starts 30mins before sunrise/sunset and ends 30mins after
- gamma correction tool support can be disabled at runtime (--no-gamma cmdline switch)
- in case of huge brightness drop (> 60%), a new capture will quickly be done (after 15 seconds), to check if this was an accidental event (eg: you changed room and capture happened before you switched on the light) or if brightness has really dropped that much (eg: you switched off the light)
- conf file placed in both /etc/default and $XDG_CONFIG_HOME (fallbacks to $HOME/.config/) support
- only 1 clight instance can be running for same user. You can still invoke a fast capture when an instance is already running, obviously
$ alias valgrind='valgrind --tool=memcheck --leak-check=full --track-origins=yes --show-leak-kinds=all -v'
$ cppcheck --enable=style --enable=performance --enable=unusedFunction
For cmdline options, check clight [-?|--help] [--usage].
Please note that cmdline "--device" and "--backlight" switches require only last part of syspath (eg: "video0" or "intel_backlight")
A global config file is shipped with clight. It is installed in /etc/default/clight.conf and it is all commented.
You can customize it or you can copy it in your $XDG_CONFIG_HOME folder (fallbacks to $HOME/.config/) and customize it there.
Both files are checked when clight starts, in this order: global -> user-local -> cmdline opts.
Gamma support is only available on X. Sadly on wayland there is still no standard way to achieve gamma correction. Let's way with fingers crossed.
Consequently, on not X environments, gamma correction tool gets autodisabled.
As clightd getgamma function properly supports only 50-steps temperature values (ie if you use "setgamma 6000" and then getgamma, it will return 6000. If you use setgamma 4578, getgamma won't return exactly it; it will return 4566 or something similar.), do not set in your conf not-50-multiple temperatures.
Moreover, since there is still no standard way to deal with gamma correction on wayland, it is only supported on X11.
If you run clight from wayland or from a tty, gamma support will be automatically disabled.
You can only run one clight instance per-user: if a clight instance is running, you cannot start another full clight instance.
Obviously you can still invoke "clight -c" from a terminal/shortcut to make a fast capture/screen brightness calibration.
This is achieved through a clight.lock file placed in current user home.
Build and install:
$ make
# make install
Uninstall:
# make uninstall
Clight is available on AUR: https://aur.archlinux.org/packages/clight-git/ .
Deb package for amd64 architecture is provided. You can find it inside Debian folder.
Moreover, you can very easily build your own packages, if aforementioned package happens to be outdated.
You only need to issue:
$ make deb
A deb file will be created in Debian folder.
Please note that while i am using Debian testing at my job, i am developing clight from archlinux.
Thus, you can encounter some packaging issues. Please, report back.
This software is distributed with GPL license, see COPYING file for more informations.