[winswitch] XPRA: shadowing only the external monitor

[Sergio Callegari]

Hi,

I would like to know if using xpra it is possible to shadow only one 
part of a display, namely the one corresponding to an external monitor.

It is my understanding that the shadow operation mode shadows a full 
display. Namely if you have an external monitor attached, that is 
placed, e.g. right of your standard screen via xrandr, xpra will shadow 
the full display area (namely the one extending from your standard 
screen to the right to include also the area corresponding to your 
external monitor).

Is it possible to shadow only the area corresponding to the external 
monitor?

This would be extra-useful. Specifically, it would let you attach a 
"virtual display adapter" to the external (HDMI/DP) port of a computer 
(see https://www.amazon.com/s?k=virtual+display+adapter) to pretend that 
there is an external monitor attached and make your desktop environment 
and applications use it. Then it would let you virtualize this monitor 
over xpra to some other place (e.g. inside a web-browser in a tablet). 
In other words it would let you do the same thing that can be done with 
deskreen (https://deskreen.com/), but most likely with the better 
efficiency and flexibility of xpra in terms of encodings, etc.

Any clue?

Thanks, best regards,

Sergio