Lunar

Note: Lunar changes the actual (physical) brightness and contrast of the monitor. It doesn't use a software overlay.

Installation methods

Sync-based Adaptive Brightness (and contrast) based on the built-in light sensor of the Macbook or iMac
Location-based Adaptive Brightness (and contrast) based on the sunrise/sunset times in your location
App Exception list if you need more brightness for specific activities (watching movies, design work)
individual settings per display
Manual controls hotkeys for setting brightness and contrast that respect the min/max values per monitor

It doesn't interfere at all with the native adaptive brightness that macOS implements for the built-in display.

If Lunar freezes your system, make sure you have the latest version installed
- Version 2.9.1 was trying to read the monitor brightness periodically through DDC and if the monitor didn't support that, the system freezed
If you activated the Read Monitor Brightness Periodically and your system freezes when using Lunar
- Make sure Lunar is not running
- Open Terminal.app
- Run the following command defaults write site.lunarapp.Lunar refreshBrightness 0
- If the above doesn't work, you can reset Lunar settings by deleting the following file:
  - ~/Library/Preferences/site.lunarapp.Lunar.plist
- If Lunar starts at login and freezes the computer before you can do anything, try doing the above in Safe Mode
If you get system lag or occasional UI freeze, this might be caused by a slow DDC response from the monitor
- Make sure Smooth Transition is turned off in Lunar preferences
- If you are using Sync mode, set the Polling Interval to a bigger value like 5 seconds to avoid making DDC requests too often

Lunar usually doesn't work with monitors connected through USB hubs/docks/adapters because a lot of them don't forward DDC messages properly
Sync mode doesn't work when the Macbook lid is closed because the light sensor is completely covered

Run make dev to prepare dev environment.