New Wayland Protocol Proposed for Dynamic Virtual Output Creation
A new Wayland protocol proposal, ext-transient-output, aims to allow privileged clients to dynamically create and manage virtual displays for remote desktop applications.
Wayland developer Simon Ser submitted a merge request for ext-transient-output, a protocol allowing privileged clients to create virtual outputs dynamically.
Remote desktop software like VNC servers currently lacks a standard way to add or remove displays on Wayland. Under this proposal, privileged clients can create independent virtual outputs. The compositor removes each virtual output when the client destroys the object.
The created wl_output global ties to no hardware device. This protocol works alongside output capture protocols such as ext_output_image_capture_source_manager_v1.
Ext-transient-output follows ext-transient-seat, which allows privileged clients to create independent seats dynamically. Transient seats and virtual keyboard and pointer input protocols already cover the input side. Now, ext-transient-output handles the display side so remote sessions can run without depending on physical monitors.
Once created, you can capture the output using ext-image-copy-capture for display by a remote client. This provides remoting software with a defined path to create, capture, and tear down a display without compositor-specific workarounds.
The protocol remains a proposal. An experimental implementation exists as a draft merge request for the wlroots compositor library. It is not yet merged into the Wayland protocols collection, and no other compositor support has been announced.