Qt Wayland Compositor Examples - Multi Screen▲
Multi-screen is a desktop-style Wayland compositor example for multiple screens.
When a client creates a shell surface, one ShellSurfaceItem is created on each screen. The ShellSurfaceItem will be visible only on one (or two) screens at a time. ShellSurfaceItem positions are synchronized so that when windows enter one screen they are moved off another at the same time.
WaylandQuickItem::setPrimary() is called at appropriate times to set the primary view for the ShellSurface, which is used when the client asks to be maximized or fullscreen.