Control display brightness from a Tauri application.

DDC/CI for external monitors, ddcutil for NVIDIA and docks, kernel backlight for internal laptop panels.

This plugin is not officially approved by the Tauri Programme. It follows the Tauri plugin conventions, so it can be adopted upstream, but only codebases inside the tauri-apps GitHub organisation are official. TAURI is a trademark of The Tauri Programme within the Commons Conservancy.

Contents

• Why two crates
• Install
• Backends
• Platform support
• Linux permissions
• Documentation
• Development
• Contributing
• License

Why two crates

Brightness control is useful outside a webview, so the engine is published on its own and the plugin is a thin layer over it:

Crate	What it is
tauri-brightness-core	The engine. No Tauri, no GUI toolkit. Use it from any Rust program.
tauri-plugin-brightness	The Tauri 2 plugin: commands, permissions, Rust API.
tauri-plugin-brightness-api	Typed JavaScript bindings.
examples/tauri-app	Tray application that uses every feature, including the diagnostic panel.

Install

cargo add tauri-plugin-brightness
npm add tauri-plugin-brightness-api

Register the plugin and allow its commands:

// src-tauri/src/lib.rs
tauri::Builder::default()
    .plugin(tauri_plugin_brightness::init())
    .run(tauri::generate_context!())
    .expect("error while running tauri application");

// src-tauri/capabilities/default.json
{ "permissions": ["brightness:default"] }

Then use it from the frontend:

import {
  diagnose,
  listMonitors,
  setBrightness
} from 'tauri-plugin-brightness-api'

const monitors = await listMonitors()

for (const monitor of monitors) {
  console.log(`${monitor.name}: ${monitor.brightness}/${monitor.max}`)
}

if (monitors.length === 0) {
  // Explains which permission is missing instead of failing silently.
  const report = await diagnose()
  console.warn(report.suggestions.join('\n'))
} else {
  await setBrightness(monitors[0].id, 50)
}

The full reference, including the Rust API, the permission list and the troubleshooting guide, is in the plugin README.

Backends

Three backends are tried in order, and the display identifiers say which one handled each monitor:

1. DDC/CI over I2C through the pure Rust ddc-hi crate. Fast, in process, and the default choice.
2. ddcutil, the standard Linux DDC/CI tool. Slower, but it is the only backend that works with the NVIDIA proprietary driver, USB-C docks and DisplayLink adapters.
3. Kernel backlight at /sys/class/backlight. Internal laptop panels are not DDC/CI devices, so they are always enumerated in addition to the others.

Platform support

Platform	Supported	Notes
Linux	✓	DDC/CI, ddcutil and kernel backlight
Windows	Partial	DDC/CI through the Windows API backend of ddc-hi
macOS	Partial	DDC/CI through the macOS backend of ddc-hi
Android	✗	Not a desktop concept
iOS	✗	Not a desktop concept

Linux permissions

External monitors need I2C access; internal panels do not.

sudo modprobe i2c-dev
sudo usermod -aG i2c "$USER"   # then log out and back in
sudo apt install ddcutil       # optional but recommended

If no display is detected, the diagnose command reports which of these is missing and prints the command to fix it. The example application shows this in a panel instead of a slider that does nothing.

Documentation

Document	Read it when
Plugin reference	Using the plugin: every command, the permission list, and troubleshooting
Engine reference	Using the brightness control outside Tauri
Example application	Seeing a full tray app built with the plugin
docs/	The project's place in the Tauri ecosystem
SECURITY.md	Reporting a vulnerability, and the fixed ones
CHANGELOG.md	What changed in each release

Contributing

Contributions are welcome. The example application doubles as the integration test, and hardware behaviour cannot be covered by unit tests, so please say which monitor and desktop environment you tested against.

cargo test --workspace
cargo clippy --workspace --all-targets -- -D warnings

See CONTRIBUTING.md for the repository layout and the testing expectations, and CODE_OF_CONDUCT.md for the community guidelines.

Development

The workspace needs Rust 1.90 or newer, driven by tauri 2.12.

cargo test --workspace
cargo clippy --workspace --all-targets

cd crates/tauri-plugin-brightness/examples/tauri-app
npm install && npm run dev

See CONTRIBUTING.md for the layout and the testing expectations, and docs/ for the project's place in the Tauri ecosystem.

License

Licensed under either of Apache License, Version 2.0 or MIT license, at your option.