Brightness

Library and CLI tool for reading and controlling backlight and LED brightness devices exposed through sysfs.

Usage

You can browse the Brightness reference.

CLI

astal-brightness --help

List available devices, set the guessed primary screen brightness, or monitor brightness changes:

astal-brightness list --pretty
astal-brightness set 50%
astal-brightness set +10%
astal-brightness monitor

Use --subsystem leds and --name when targeting a specific LED device, such as a keyboard backlight.

Library

The singleton exposes backlights and leds device lists. It also exposes screen and keyboard proxy devices, which are guessed from the available backlight and LED devices.

brightness is a normalized value from 0 to 1; real_brightness is the raw value reported by sysfs.

JavaScript

import Brightness from "gi://AstalBrightness"

const brightness = Brightness.get_default()

print(brightness.screen.brightness)
brightness.screen.brightness = 0.5

Python

from gi.repository import AstalBrightness as Brightness

brightness = Brightness.get_default()
screen = brightness.get_screen()

print(screen.get_brightness())
screen.set_brightness(0.5)

Lua

local Brightness = require("lgi").require("AstalBrightness")

local brightness = Brightness.get_default()

print(brightness.screen.brightness)
brightness.screen.brightness = 0.5

Vala

var brightness = AstalBrightness.get_default();

print(@"$(brightness.screen.brightness)\n");
brightness.screen.brightness = 0.5f;

Installation

1. install dependencies

   Arch

   sudo pacman -Syu meson vala valadoc json-glib gobject-introspection

   Fedora

   sudo dnf install meson vala valadoc json-glib-devel gobject-introspection-devel

   Ubuntu

   sudo apt install meson valac valadoc libjson-glib-dev gobject-introspection

   INFO

   The CLI target also depends on libquarrel. Install Quarrel first, or configure with -Dcli=false if you only need the library.

   The default backend uses systemd-logind to write brightness values. To install udev rules instead, configure with -Dbrightness-backend=UDEV.

2. clone repo

   git clone https://github.com/aylur/astal.git
   cd astal/lib/brightness

3. install

   meson setup build
   meson install -C build