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DUX

An X11 backlight manager.

Installation

Using Nix, you can access build-time dependencies via the Nix shell:

nix-shell

Otherwise, please refer to buildInputs in shell.nix to check whether you have all the required dependencies installed through other means.

To install it you will need a nightly Rust toolchain, then you can install it with Cargo:

cargo install dux

Usage

dux can be used like a replacement for xbacklight, the command syntax changes slightly but the functionality is the same (get, set, inc, dec, all with the usual fade settings).

To start the adaptive brightness daemon just run:

dux adaptive &

To stop it gracefully (making sure the settings are saved) just run:

dux stop

Adaptive brightness

Adaptive brightness manages the backlight automatically for you based on the selected mode and profile.

To select a mode you can either pass a --mode <mode> when starting the adaptive brightness, or call dux mode <mode> after it's been started.

There's support for multiple profiles, to select a profile just pass --profile <name> when starting the adaptive brightness, or call dux profile <name>; profiles are useful for example to have different settings during the night and during the day, or when you're inside or outside.

To configure the brightness levels for the various modes all you have to do is change the backlight from dux itself like you would with xbacklight and the change will be saved. If you don't want to do that you can call dux sync after changing the backlight with something else.

Desktop

The desktop mode uses the current active desktop (also known as workspace in some window managers) to reload the previously set brightness.

Window

The window mode uses the active window to to reload the previously set brightness.

Tt uses both the window's instance and class name to determine the brightness, this allows for a common brightness setting for the class and a specific one for the named window.

Luminance

The luminance mode uses the screen content's contrast to reload the brightness value.

When the luminance is between two different settings it will interpolate the brightness value between the two based on the distance between them.

For example if you have 10 luminance set at 80 brightness and 50 luminance set at 20 brightness and the current luminance value is 20 the brightness will be closer to 80 than 20.

Performance wise it uses some X extensions to avoid doing heavy work, it uses the MIT-SHM extension to avoid connection pressure when fetching the screen contents and the DAMAGE extension to only fetch and recalculate the areas that have actually changed.