Mir 0.28

We are pleased to announce that Mir 0.28 has been released and is available in Ubuntu 17.10 (Artful).

As the content (and even the name) of this release has changed over the time we’ve been working towards it now is probably a good time to reflect on what it is, and what it isn’t after all.

What is in Mir 0.28?

There is now a stable server ABI

This simplifies the use of “Mir snaps” making it possible to release new library versions without breaking servers.

One of the barriers to the adoption of Mir has been the potential for Mir releases to break downstream projects that depend on a stable ABI. This is provided by libmiral, which is now part of Mir.

The Yunit project which uses Mir as part of its graphics stack has already started migrating code to use libmiral for this reason.

The start of Wayland support

The desktop community has adopted Wayland as the client-server protocol of choice for replacing X11. This is already supported by several server implementations (Weston, Kwin and Mutter are the best known). By providing Wayland support we will make Mir servers compatible with the various toolkits and libraries that already have Wayland backends.

Our MVP goal for Mir 0.28 has been to support a Wayland client with a single fullscreen surface. We have slightly exceeded this goal in 0.28 as you can see from this short video:

https://www.youtube.com/watch?v=sfcZrpkc2NU

We will continue to expand on this Wayland support in future releases.

The MirAL shells are part of Mir

The miral-kiosk shell is used by the mir-kiosk-snap to provide graphics support on UbuntuCore. This release includes a number of improvements to miral-kiosk based on feedback from potential users.

The miral-shell is now the canonical example of writing a Mir server. We’ve dropped several older examples that used other APIs (and reworked mir_demo_server to fit the new server APIs).

There is a (currently unstable) API for “graphics platform” plugins

We had planned to stabilize the graphics platform API and ABI before publishing it but we had to change that plan. Canonical no longer has the infrastructure to test and maintain the “android platform”. However there is was interest from UBports both in continuing to support the “android platform” and for developing a “Wayland platform”.

What is NOT in Mir 0.28?

We have not upstreamed Mesa distro patches

These patches support “Mir EGL” which forms part of the Mir client API. With the adoption of Wayland (and Wayland EGL) it looks likely that these will not have a long term future and upstreaming a wasted effort.

This should also become less of an issue as it only affects EGL clients using the legacy Mir client APIs. Software rendering, Xmir and Xwayland clients will work without these patches.