Proper interaction with Wayland

[tobias47n9e]

When launching Gromit on Fedora 24 in the Gnome Wayland session I get this error:

Supported backends: x11 wayland 
Using backend: wayland

(gromit-mpx:24312): GLib-GObject-WARNING
     **: g_object_get_valist: object class
    'GdkWaylandDevice' has no property named 'device-id'
Segmentation fault (core dumped)

Using the x11 session on the same machine works perfectly.

And thank you for making such a useful tool!

[bk138]

IIRC, wayland support is still preliminary. If you want to finish that, go ahead! :-)

[tobias47n9e]

I would like to, but I wouldn't even know where to start. I never tried migrating anything to Wayland before.

[bk138]

First stab would be to remove device-id access, at GdkDevice does not have this anymore https://developer.gnome.org/gdk3/stable/GdkDevice.html

All the X11-specifix code is in input.c. You'd have to
a) use generic gdk functions (if available) instead of the X stuff
OR
b) (not so nice) leave the X11 stuff in there and add Wayland specific bits in ifdfes...

[bk138]

For a), there is https://developer.gnome.org/gdk3/stable/GdkDevice.html#gdk-device-grab and friends for the grabs, whicht at the time of writing were broken and required me to use the XINput functions...

[tobias47n9e]

I had a chat with some of the Gnome developers on IRC. Because Wayland restricts programs from drawing over other programs for security reasons, the only way to have a program like Gromit under Wayland would be to (quote):

either it is in the compositor or it needs a protocol

At the moment that seems quite complicated. I might need to revisit this issue once I have a better understanding of all the parts involved. Thank you too, for explaining some of the first steps!

[russel]

I have no technical input here, just to say that I use Gromit-MPX for all my presentations at conferences and during workshops. It has become a bit of a USP, and people are always asking what software I am using. Of course I tell them, hopefully this means more users – though many of them are Windows and macOS people…

Fedora is again trying to push Wayland as the default, and ditch X – I dual boot Debian Sid and Fedora Rawhide, Sid is still very much Xorg and no Wayland, Rawhide is Wayland by default but with Xorg as an option. I understand though that Xwayland is actually a hybrid; Wayland but with X-y bits. If Gromit-MPX cannot be made to work on Wayland, then I shall remain an Xorg holdout. I appreciate that Wayland is better than Xorg conceptually, but this is about what users want to do with their computers!

I had stopped recompiling Gromit-MPX each day as I needed a stable working version guaranteed for conferences and workshops. I will though set up to do daily builds and check on Sid and Rawhide if that will help.

[bk138]

Thank you @russel ! What's needed most is some more dev personnel as I am seriously lacking time. PRs are always welcome ;-)

[bk138]

@russel Ah and have you tried Wayland support of ardesia or spotlighter?

[bk138]

@tobias47n9e I was curious and just tried it out in a wayland session and gromit-mpx worked surpisingly well under XWayland. When passing in GDK_BACKEND=wayland I got the same error as you. Did you try

GDK_BACKEND=x11 gromit-mpx -d

?

[bk138]

@tobias47n9e can you pls try 5e9aeb3 ?

[tobias47n9e]

After applying the patch I could launch the program using GDK_BACKEND=x11 gromit-mpx -d. Pressing F9 launches the draw cursor, but only after clicking on another program, clicking on the desktop is not enough). Drawing itself does not seem to work. Pressing F9 again correctly ends the drawing mode. An interesting thing is that the terminal used to launch Gromit is not selectable by mouse anymore, but just by keyboard.

[bk138]

To clarify: 5e9aeb3 should make the manual GDK_BACKEND setting obsolete. Can you test this?

Did you launch gromit-mpx from the terminal? It seems doing make install and using the GNOME launcher makes a difference...

[tobias47n9e]

Not sure why GDK_BACKEND is not chosen automatically, but it doesn't work. After a restart oddly enough I could get drawing to work. After exiting and launching again, drawing does not work anymore.

I am launching from the terminal. Using the icon segfaults like using only gromit-mpx to launch the program. Probably not enough information to debug the issue.

[bk138]

Few points here:

• restart of gromit or your Wayland session?
• you probably should not launch from the terminal but the launcher after sudo make install. pls also make sure you haven't installed the rpm/deb package as there might be concflicts.
• can you give some info about your environment? OS, desktop, etc with versions. I could setup a virtual machine and try myself...

[tobias47n9e]

• A system restart
• I didn't install an rpm package of gromit
• I am using Fedora 24 with a standard installation and Gnome desktop.

I am thinking of updating to Fedora 25 alpha soon, to try it with the newer Wayland packages.

[russel]

Sorry I haven't been able to chip in this for the last day or so. I should be able to try things out on Fedora Rawhide (F26 currently) over the weekend.

[bk138]

a3bd7ab should fix that particular issue here, but not the Wayland functionality as a whole...

[bk138]

General update: issues with Gromit-MPX can now be funded at https://issuehunt.io/r/bk138/gromit-mpx

[bk138]

Getting back to this, here a some things that need fixing

• the hotkey has to be defined in the compositor, for gnome-shell
  • this could be sth like https://askubuntu.com/a/597414/344291 and for flatpak Quick Add does not work in flatpak alainm23/planify#246 -> fixed via 6501486 and 1d62dc0
  • or maybe https://bugzilla.redhat.com/show_bug.cgi?id=1285770#c33 (does not work) ⛔
  • https://bugzilla.redhat.com/show_bug.cgi?id=1500397 states there is upstream support from Xwayland 1.20 on, which https://wiki.archlinux.org/index.php/Wayland#Input_grabbing_in_games,_remote_desktop_and_VM_windows confirms. Only works when X11 window visible: ⛔
• the IPC via selections does not work as expected under Wayland. But does under XWayland, forced by 81c2bd2
• after the first toggle-on, a click on the tray icon area is needed. It seems that in XWayland-world, the window is brought to the front and the pointer grabbed (as there is a cross-hair over XWayland-apps) but Wayland-clients are unaffected until XWayland is "activated" (funnily enough it sometimes is not, even when the X11 window of Gromit-MPX is shown...). Fixed by 56a6fb6
• no MPX anymore under wayland, but "seats" -> tackled in Implement multi-pointer support for Wayland sessions #103
• modifier keys don't always work under xwayland -> tackled in Modifier keys like Shift, Ctrl, Alt don't always work under XWayland #106

[bk138]

Closing as as basic functionality works, #103 and #106 keep track of remaining Wayland-related issues.