OpenDisplay is a free, open-source way to use an iPhone, iPad, or spare Mac as a true second monitor for a Mac. It creates a virtual display that macOS treats as an extended desktop rather than merely mirroring the main screen. Video is captured and hardware-encoded as low-latency H.264 before being streamed to the receiver. Connections can run over USB for minimal latency or Wi-Fi with Bonjour-based discovery. Retina and HiDPI output preserve sharp text, while touch gestures provide...