Brightness Service

[English | 简体中文]

The brightness service provides automatic screen brightness control based on light sensor input, and can adjust the control curve accordingly in response to user input.

The service depends on several other modules including libuv, uorb, and video drivers. If KVDB is enabled, user settings will be persisted.

Project Structure

├── abc.c
├── display.c
├── lightsensor.c
├── persist.c
├── spline.c
├── aidl
├── README.md
└── README_zh-cn.md

• abc: Short for auto-brightness-controller, is the main controller.
• display: It set/get brightness and also handles smooth transition.
• lightsensor: Manages sensor input and data filter.
• persist: Use KVDB to store/restore user settings.
• spline: Calculates the user added control point.
• aidl: Adds AIDL layer to expose brightness services to other tasks.

Usage

Start the service

The brightness service should start with systemd.

Interact with brightness service

It's recommended to use the AIDL interface to control brightness mode and set brightness level. A C wrapper is provided in include/BrightnessServiceC.h.

To set brightness mode, simply call BrightnessService_setBrightnessMode.

• BRIGHTNESS_MODE_AUTO Auto mode is to let the controller automatically read sensor and decides current brightness level.
• BRIGHTNESS_MODE_MANUAL Manual mode allows to set the brightness to any value.

Two special brightness level BRIGHTNESS_LEVEL_OFF and BRIGHTNESS_LEVEL_FULL are provided to set turn off display or to full brightness.

If KVDB is enabled, the user settings including mode and level are automatically saved and will be restored upon next power up.