Latest version of Canonical's Wayland compositor arrives

Canonical is still working away on its own Mir display server, used in several of its IoT product lines. Version 2.14 gains more functionality useful for full desktop environments.

Mir is a complex project which has undergone some big changes over its more than a decade of existence, and it has several subprojects now, including the Lomiri desktop, which not only natively runs on Debian but is included as part of Debian 12.

Mir 2.14 – that's version 14 of Mir 2, not version two-point-one-four – is out, and supports a larger range of Wayland functionality. The announcement says this release brings support for Wayland screenlockers (the ext-session-lock-v1 Wayland extension protocol), and support for Drag 'n Drop, which also means that "attached" windows can be "restored"" by a drag gesture. It has improved nVidia hardware support, and fixes an evdev handling bug.

Since version 2.0, Mir has been a pure Wayland compositor, although the fondleslab version still uses the older Mir 1.8, because that also supports the older mirclient APIs. In fact, it's not so much a Wayland compositor; as lead developer Alan Griffiths told The Register: "Mir is a set of libraries for building Wayland compositors."

He went on to say: "There are a number of projects that use these libraries, the most significant being Ubuntu Frame, Lomiri and Miriway."

However, none of these are exactly household names, so we don't blame you at all if you're not familiar with them — we weren't. It is perfectly OK if you're not completely clear on exactly what a "Wayland compositor" is, because this stuff is not very well-explained by the big desktop projects that use it. This is why the Mir docs have a section titled "OK, so what is this Wayland thing, anyway?", which we found quite helpful.

Wayland itself is a protocol, like X11 is a protocol. Different programs implement Wayland, just as different ones implement X11, such as X.org on FOSS Unix, Xsun in SPARC Solaris, or on Windows, Xming, Reflection or MI/X, among others.

Part of the confusion comes in with the term "compositor". A Wayland compositor is not same sort of program as an X11 compositor, which as the Arch Linux wiki says is just a type of X.org extension.

A Wayland compositor combines two functions that with X11 are separate programs: the display server and the window manager. So, several programs that were "just" window managers under X11, such as GNOME's Mutter and KDE's Kwin, have been extended into Wayland compositors, meaning that they are also display servers in their own right.

Of the three projects that Griffiths told us about, he said, "Ubuntu Frame is the commercial focus for Mir work." Frame isn't a window manager at all: it is intended for standalone kiosk-type roles, where one app controls the whole screen all the time. It's distributed as a Snap package, so it will run on most distros, but a primary target is Canonical's IoT distro Ubuntu Core.

Lomiri – formerly known as Unity 8 – we've talked about before. It's a converged desktop and touchscreen environment, Griffiths said, "which is 'inspired by' Unity desktop, and why Mir was needed in Debian."

The third use of Mir was new to us, though. Miriway, he confirmed, "is a lightweight/proof-of-concept 'desktop environment'."

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It seems to be a loose successor to EGMDE, which the Mir homepage describes as:

Miriway started out as a holiday project, but he describes it as "somewhat usable out of the box".

Griffiths has posted a demonstration video on YouTube, of which he told us: "Those experiments are based on building and installing the Github project locally (not the snap) and running the example-configs scripts. The same stuff works with the snap – it just needs a slightly modified config (adding miriway-unsnap as needed)."

As a look at the current state of the Wayland compositor ecosystem, the Arch wiki's list of them shows many are based on wlroots. Rather than a compositor in its own right, wlroots is a set of libraries for building a compositor, which multiple teams have used to build relatively simple tiling window-manager-like environments, such as Sway, Wayfire, dwl (which aims to be dwm for Wayland), and japokwm. Aside from GNOME and KDE, for now, most of the activity in Wayland-land (sorry) seems to be very simple tiling environments.

Youtube Video

For a set of tools that we suspect many people thought was killed off in Ubuntu's great purge of 2017, Mir is livelier than you might expect. As we said recently, it increasingly looks like Wayland is the future of Linux GUIs. Mir's inclusion in Debian, and the Lomiri, EGMDE and Miriway projects, all constitute hopeful signs that Mir could provide a basis for something a bit richer than a choice of tiling window managers. ®