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neallindsay

Linux users probably already have some weird workflow with X11 virtual buffers to do this.

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This is how I do it under Sway (Wayland):

#!/bin/bash

swaymsg create_output OUTPUT=$(swaymsg -r -t get_outputs | jq '.[].name' | grep HEADLESS | tr -d '"')

# No need to reduce res, it defualts to 1080p #swaymsg output "$OUTPUT" resolution 1280x720

wl-mirror "$OUTPUT"

swaymsg output "$OUTPUT" unplug

When I was still in X11 land I used to just use Xephyr.

Ooh, creating a headless display and then wl-mirroring it is incredibly smart! Have been looking for something like this!

I just realized formatting is a bit broken. :(

Fixed:

#!/bin/bash

swaymsg create_output

OUTPUT=$(swaymsg -r -t get_outputs | jq '.[].name' | grep HEADLESS | tr -d '"')

# No need to reduce res, it defualts to 1080p

# swaymsg output "$OUTPUT" resolution 1280x720

wl-mirror "$OUTPUT"

swaymsg output "$OUTPUT" unplug

You can do code blocks on HN by prefixing your lines with four spaces.

    #!/bin/bash
    swaymsg create_output
    OUTPUT=$(swaymsg -r -t get_outputs | jq '.[].name' | grep HEADLESS | tr -d '"')
    # No need to reduce res, it defualts to 1080p
    # swaymsg output "$OUTPUT" resolution 1280x720
    wl-mirror "$OUTPUT"
    swaymsg output "$OUTPUT" unplug

Four spaces!? Absurd! Think of how many bytes you're wasting! In just your last code block your flooded the internet with 28 needless bytes!?!?!?!! If this keeps up soon we'll all just be downloading whitespace.

Only two spaces are needed: https://news.ycombinator.com/formatdoc

  function trim {
    sed -e 's/^[[:space:]]*//' -e 's/[[:space:]]*$//'
  }

/end sarcasm

You just cut my tedious space-bar-smashing time in half, thank you!

Oh, thanks! I remembered there was something, skimmed through https://news.ycombinator.com/formatdoc and completely missed it.

HN needs a dedicated pastebin (remember those?)

What "remember"? I'm in multiple Matrix channels right now that tell people to use them.

Personally I don't bother with a virtual display. I automatically set my display scale to 2x when I start screen sharing. I set that up with exec_before and exec_after hooks in xdg-desktop-portal-wlr[0]. In addition to turning off my notification daemon (so my email/instant message notifications don't pop up), my exec_before/exec_after scripts just run:

    swaymsg output "MY-MONITOR" scale 2 # or 1 for exec_after

With that, everything puffs up big and readable when I'm screensharing and seamlessly shrinks back down when I stop screen sharing. No need to juggle windows around to different displays.

[0] https://man.archlinux.org/man/extra/xdg-desktop-portal-wlr/x...

I use `xrandr --setmonitor` to create a fake monitor that only covers part of my screen. And I have some window manager setup to easily move my windows there (with awesomewm).

That's a good solution. I used xnest

Xnest is probably enough. I've used it for similar purposes a few times. Don't know the equivalent for Wayland though.

Yes, Wayland compositors like cage and sway can be nested too.

That said, with both the X nesting approach and the Wayland nesting approach, you'd also need to run the screencasting application itself inside the nested server, not the just the application you want to cast. If the compositor supports a way to create headless outputs (as sway and hyprland do) that is much easier.

Xnest got replaced by Xephyr AFAIK. But same thing at the end of the day.

It's not exactly the same, but as an alternative to what jauntywundrkind you can use V4L2-Loopback and OBS to create a virtual webcam and use that to share your screen. I find it really handy being able to switch between either just my cam, my desktop or both.

Yeah. On Wlroots or Sway, we can setup virtual displays pretty easily (swaymsg create_output, done). Run wayvnc, and both the other person and yourself connect over vnc or rdp to see what's over there.

Available May 2020, https://github.com/any1/wayvnc/issues/7#issuecomment-6256611...

For Hyprland, the command is `hyprctl output create headless NAME`

As a Linux user who generally prefers to avoid the command line for things user friendly applications should be able to do, I'll stick with OBS. That solution also works on Windows, which is extra nice.

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