Xwayland XDG shell Protocol rootless

[Scott Anderson]

On 17/03/21 12:13 am, Julian Albrecht wrote:
> Hi,
> 
> 
> At the moment I use Xwayland together with the QWayland compositor. I 
> was wondering why XDG shell is not supported in rootless mode, instead 
> all communication goes through the window manager. Is this a deliberate 
> design decision? Especially for the compositor it would be easier if 
> Xwayland itself would support the XDG shell for rootless windows.
> 
> 
> Best regards
> 
> Julian

Hi,

At the time XWayland was originally written, xdg-shell didn't exist, but 
the same argument could've been extended to (the now deprecated) 
wl_shell protocol.

Basically, there isn't any actual advantage to using xdg-shell for this.

The X and Wayland way of handling more "advanced" window-related 
concepts are incompatible enough that trying to map it to 
xdg-shell/wl_shell wouldn't work very well. For example, many of the 
possible values of _NET_WM_WINDOW_TYPE do not have an equivalent.

Also, the Wayland compositor needs to act as an X window manager anyway, 
so it makes sense to just use the native X way since it's already 
speaking X, and it can have its own policy about how it wants to handle 
X-specific things.

Scott