# Screen sharing

"We use `xdg-desktop-portal` (+ backend implementation) for communication
between the app requesting to share a screen and between desktop (Plasma or
Gnome)." [1] (or in this case, sway). See also [2].

**System info**

```
=== Kernel ===
6.18.18-1-lts
=== Sway ===
sway version 1.9
=== xdg-desktop-portal (installed packages) ===
xdg-desktop-portal 1.20.3-2
xdg-desktop-portal-wlr 0.8.1-1
xdg-desktop-portal-gtk 1.15.3-1
```

**Logs**

```
Mar 15 09:22:00 andreas-laptop systemd[1178]: xdg-desktop-portal-gtk.service: Start request repeated too quickly.
Mar 15 09:22:00 andreas-laptop systemd[1178]: xdg-desktop-portal-gtk.service: Failed with result 'exit-code'.
Mar 15 09:22:00 andreas-laptop systemd[1178]: Failed to start Portal service (GTK/GNOME implementation).
Mar 15 09:22:00 andreas-laptop /usr/lib/xdg-desktop-portal[1347]: Failed to ReadAll() from Settings implementation: GDBus.Error:org.freedesktop.DBus.Error.NameHasNoOwner: Could not activ>
```

**Solution**

We first have to tell `xdg-desktop-portal` that it should use the wlr backend
to route screen capture requests. In `~/.config/environment.d/sway.conf` add
```
XDG_CURRENT_DESKTOP=sway
```

We also have to set up the link between the wayland compositor and
`xdg-desktop-portal`. In `~/.config/sway/config`, add
```
exec systemctl --user import-environment DISPLAY WAYLAND_DISPLAY SWAYSOCK XDG_CURRENT_DESKTOP
exec dbus-update-activation-environment --systemd DISPLAY WAYLAND_DISPLAY SWAYSOCK XDG_CURRENT_DESKTOP
```

## References

1. https://jgrulich.cz/2018/07/04/how-to-enable-and-use-screen-sharing-on-wayland/
2. https://wiki.archlinux.org/title/XDG_Desktop_Portal