blinryWhoa: Weston, the reference compositor for #Wayland, supports multiple physical independent mice at the same time! 😀
"New mouse, who dis?"
(See toot later in the thread for how to set this up!)
There are couple of surprises around window interaction:
- Once a cursor starts to resize/move a window, those actions are not possible for the other one.
- One cursor can open a menu, and the other one can use it, that one works pretty well!
- Closing a window with one cursor, while the other drags it, makes the second one *disappear*! :D
I mean, these are really hard UI questions to solve! Often, it's not clear to me what the correct behavior should be!
Okay, let's try some applications, and see how they deal with multiple mice! 😈
First up: Gedit, a GTK application.
Both cursors can place the cursor and select text, but movement from one cursor "interrupts" the selection of the other one. Not very satisfying.
Imagine how cool it would be if both had their own selections + cursors!! That would allow a really neat form of collaboration within the same document!
Next up: Chromium! It has a very pragmatic solution: It just *ignores* all cursors but the first one!
In the video, the arrow-shaped cursor can click on stuff. The turtle has no power here.
In Firefox, it seems like all mouse events are mashed together, and are seen as coming from the same device.
That means that both cursors can click – if the other one "holds still". Otherwise, I guess Firefox is very confused by a click on a link while the mouse is not in it! 😆
Selections feel strange – the last-moving cursor will determine the selection.
Also notice how, if one cursor hovers a link, *both* turn into hand icons!
Of course, we *had* to try a drawing application next!
Here's @tldraw (in Firefox)! 
Collaborative drawing at it's best! 💚
Finally, I tried attaching an additional keyboard and assigned them to a different "seat"!
That worked really well! In Weston, each "seat" has its own keyboard focus, so you can actually work side-by-side with two mice + two keyboards independently!
Also!!! The two seats have their own (independent) clipboards!!!! Whatttt! 🤯
I totally didn't expect this. But multi-seat as a concept seems deeply integrated into libinput + #Wayland! Now it's up to GUI toolkits and compositors to support it!
Tried it again, and the independent clipboards still seem a bit glitchy after all… :(
An issue asking for proper support in GTK was closed five years ago, for example… https://gitlab.gnome.org/GNOME/gtk/-/issues/1574
Goaty McGoatFaceSide note: I think more window managers should support *this* feature!
Very useful when your very long line of code doesn't fit on your screen, for example! :P
(Shout-out to @xssfox, who first did this on X.org! https://sprocketfox.io/xssfox/2021/12/02/xrandr/)
Okay, here's how to set this up!
You need to create a udev rule for the "second" input device that sets ENV{WL_SEAT} to a string other than "default", and then start Weston from a virtual console. (At least, starting it from another Wayland session didn't work for me.) That's it!
The WL_SEAT property is what Wayland refers to as a "logical seat". Assign the same seat name to a mouse and a keyboard to make them work together! The default seat is "default".
Detailed steps:
1. Use `sudo libinput list-devices` to find the device file (like "/dev/input/event12")
2. Use `udevadm info -a /dev/input/event12` to find the parent device with a catchy ATTRS{name}.
3. Create a file /run/udev/rules.d/00-multiseat.rules like this:
ATTRS{name}="Name of your mouse" ENV{WL_SEAT}="second"
4. Run `sudo udevadm trigger` to apply the new rules.
You can check again with `sudo libinput list-devices`. The device's "Seat" should now say "seat0, second"!
You could try this script (requires zenity & possibly more tools? Please read before running!) https://github.com/n3rdopolis/rebeccablackos/blob/master/rebeccablackos_files/usr/bin/configureseats
(Doesn't work on #NixOS, where /etc/udev is read-only. 💀)
I'd love to have a little command line helper tool to help set this up, for an arbitrary number of mice! :D
This was a fun afternoon! Thanks for following along.
Let me know which other programs I should try with multiple mice! :D
Looks like SDL (the multimedia library) very recently merged support for multi-seat input! https://www.phoronix.com/news/SDL-Merges-Wayland-Multi-Seat
So… many-mouse games should be possible on Wayland? :3
Lynx@blinry that's awesome! Though I will point out that multi mouse support has totally been possible all along (even back in X11) if you use direct input device access instead of using input events from the windowing system. I played with that a bunch back when I was still making games in Crystal Space.
zormit
Tekknovator@blinry please try Ardour and bespoke. Ardour uses its own flavor of gtk, if I understood correctly. Bespoke synth, idk.
Oh, VCV Rack would be interesting too. Imagine patching with collaborators. Like a real eurorack session.
Oh, VCV Rack would be interesting too. Imagine patching with collaborators. Like a real eurorack session.
Sandro 
dtomvan
Klaus Frank@blinry have you by change tried if it also works with a monitor or GPU the same? I've a KVM integrated into the server mainboard and it would be great to put that onto it's own seat and have a dedicated GUI running there. Otherwise it always causes bad application behavior with graphics acceleration when it pics the wrong GPU to run on...
@agowa338 I *think* that's what the physical seats are for! ENV{ID_SEAT}. But I haven't tried it at all! https://www.freedesktop.org/wiki/Software/systemd/multiseat/
@blinry I tried to use seats a few years ago, but documentation was shit. I never figured out how to properly configure them. I didn't even find that it was a udev rule thing back then.
Also a lot of people in forums and mailing lists told me that they're not even aware of that feature existing to begin with. (there wasn't a single one that know that this feature exists and also knew how it worked)
So at some point I just gave up on it.
Maybe it's time to check it out again by now.
Raven667
Peter HuttererPhysical seats effectively signal "this is a different computer" except it shares some of the same hardware.
Logical seats effectively signal "this is a different person" so they share the environment but work independently within that environment (mouse, keyboard focus, etc).
Except sometimes a logical seat is a different *hand*, not person (because you may want left and right hand to work independently, hence two logical seats) and wheee, off into the rabbit hole we go.
Haelwenn /элвэн/ 
DerPumu (he/him)
Robin Syl 🌸
Anthropy@blinry It's especially useful if you want to create flat smart surfaces where you want multiple people to interact with it at once, from their own corner of the table. Still kinda wish we would see some Microsoft Surface (the original one https://en.wikipedia.org/wiki/Microsoft_PixelSense ) but Linux based, it seems entirely feasible
LucileDT
imikotoba 🏴❤️🇯🇵@blinry I was struggling to come up with a single use case aside table top flat screens (like a mutltitouch table where people could be viewing from any angle)
Ruud Steltenpool@imikotoba @blinry Use red/green glasses so you can read text upside-down too?
SchwarzeLocke@blinry I see the use case at a tablet / table, which is used by two different persons sitting next to each other.
Daniel Bohrer@blinry …does this count? 😁
(Came back to my resized terminal window after it had been auto-migrated to the other screen by the window manager when changing screen layouts)
(Came back to my resized terminal window after it had been auto-migrated to the other screen by the window manager when changing screen layouts)
gilbert gabagool garden
ʙwɑnɑ нoɴoʟʊʟʊ 
@blinry Ja, aber sowas führt zu… https://estrogen.network/notes/a8wokso2w2ubchev … so was. 🙃
@blinry 90°-steps rotating could be neat but freely rotating… I feel like it's more a meme than anything else
Sven@lanodan @blinry Weston is a bit of a demo of what compositors can do too vs something they expect you to fully use for your desktop.
And rotation would e.g. be useful for a specialized compositor for tabletop applications. (had to fake that many years ago for a floor-scale display, doing an actual compositor would've been fun)
Freeeeeeeeeeeeeeeeeeeeeeeeeee 
could maybe be nice for touchscreen laptops and tablets actually
Joshua Barretto
Stewart Russell@blinry as someone who still prefers outline moving/resizing, I most certainly hope not!
shork
Vrrroooom (gravy era)@blinry im hyperventilating
@blinry i want a button that shakes it all up and tumbles the windows ontop of each other like theyve been dumped out of a bucket
i would use this responsibly i promise
@SarraceniaWilds Hehe :) And maybe a small fireplace to the side, so that you can finally BURN the windows that annoy you? 🔥 https://en.wikipedia.org/wiki/Little_Inferno
@blinry yes yes yes and if the cursor gets too close it catches fire and changes its icons to various charcoal lumps or burnt twigs
@blinry computers should be fun
@SarraceniaWilds Ha yeah!
Maybe Firefox would be immune? And all note-taking apps are extremely flammable!
@blinry i need this to be real so i can open an issue in the repository that devolves into pokemon like discourse about which software will and wont burn
Solarbird 
I WOULD ALSO ONLY USE THIS RESPONSIBLY I SWEAR
Tobias
jesterchen42@blinry I'm still waiting for non-rectangle windows. And I mean non-rectangle, not partial transparent rectangle windows. 🤭
These may be ofc tilting as well.
Or give me a 3d desktop, with glasses and everything, so you can out windows behind others and then look from the side... or take a walk along the desktop scebery.
robelix
leyrer
ticho
StarkRG
myrmepropagandist
Mr. Bruno 
Semitones
Uckermark MacGyver 
Mer-fOKxTOwl@blinry its so cursed!
but with a multi input screen flat on a table with people sitting around and working together its not even that far off anymore.
but i guess that needs a lot of other bits refined to be a thing people would even want to use.
otske lasha@blinry
Da müsste man noch eye tracking machen und könnte dann die Fenster automatisch neigen, wenn man den Kopf schief legt.
Wenn man dann vor seinem Rechner was erklärt und mit dem Kopf schüttelt, .... das wäre voll toll!
nihilistic_capybara@blinry potentially useful for tablets.
What os is that?
Edit: nevermind it was enough to scroll up
@nihilistic_capybara Linux, the compositor/window manager is https://en.wikipedia.org/wiki/Wayland_(protocol)#WESTON
