First release of the rewritten ddc-mirror.
A tiny macOS LaunchAgent that watches the built-in MacBook display's brightness and mirrors it to every connected external monitor. No UI, no settings, no flags.
What's in the box
- Single-file Objective-C, 55 KB binary, zero external dependencies
- Auto-picks the right mechanism per display at startup:
- Apple-native API for Studio Display / Pro Display XDR
- DDC/CI (
IOAVServiceWriteI2CVCP0x10) for monitors on direct cables - Software gamma dimming (
CGSetDisplayTransferByFormula) for monitors behind docks/hubs/KVMs that strip DDC
- Push-driven via
DisplayServicesRegisterForBrightnessChangeNotifications— no polling, sub-frame latency - Re-bootstraps on hot-plug and on wake from sleep
- Restores factory gamma on exit
Install
brew install emin93/tap/ddc-mirror
brew services start ddc-mirrorApple Silicon (M1+), macOS 12+.