Virtual screen

A BetterDisplay virtual screen is a software-created display that macOS can use as a desktop without a physical panel. Its configured dimensions and modes determine the desktop sizes it offers.

To view that desktop, you can use it as the source for mirroring or streaming to another display, or show it in a Picture in Picture window. Creating the definition, connecting it to macOS and presenting its contents are three separate operations.

An association can tie its connection to selected displays. This lets a virtual screen participate in a particular setup without confusing its saved definition with whether it is currently connected.

See Display mirroring, Picture in Picture and HiDPI for related concepts. Virtual Screen explains configuration and connection management.

For the underlying rendering method, see what flexible scaling and custom resolutions change.