miral gets cut & paste

For some time now I’ve been intending to investigate the cut & paste mechanisms in the Unity8/Mir stack with the intention of ensuring they are supported in MirAL.

I’ve never had the time to do this, so I was surprised to discover that cut & paste is now working! (At least on Zesty.)

I assume that this is piggy-backing off the support being added to enable the “experimental” Unity8 desktop session, so I hope that this “magic” continues to work.

MirAL 1.3.1

There’s a bugfix MirAL release (1.3.1) available in ‘Zesty Zapus’ (Ubuntu 17.04) and the so-called “stable phone overlay” ppa for ‘Xenial Xerus’ (Ubuntu 16.04LTS). MirAL is a project aimed at simplifying the development of Mir servers and particularly providing a stable ABI and sensible default behaviors.

Unsurprisingly, given the project’s original goal, the ABI is unchanged.

The bugfixes in 1.3.1 fall are:

In libmiral a focus management fix:

When a dialog is hidden ensure that the active window focus goes to the parent. (LP: #1671072)

In the miral-shell example, two crashes fixed:

If a surface is deleted before its decoration is painted miral-shell can crash, or hang on exit (LP: #1673038)

If the specified “titlebar” font doesn’t exist the server crashes (LP: #1671028)

In addition a misspelling of “management” has been corrected:

SetWindowManagmentPolicy => SetWindowManagementPolicy

Mir and Zesty

Mir is continuing to make progress towards a 1.0 release and, meanwhile, Zesty Zapus (Ubuntu 17.04) is continuing to make progress towards final freeze.

Currently the version of Mir in Zesty is 0.26.1 and we’re not planning any major changes for the 17.04 series. We’re probably going to make a bugfix release (0.26.2). The other possibility is that work on supporting hybrid graphics is completed in time for adequate testing for 17.04. In the latter case we’ll be releasing Mir 0.27 to get that shipped.

For this and other reasons it isn’t yet clear whether there will be a 0.27 release before we move to 1.0.

The significance of a 1.0 release is that it will be the time we break the mirclient ABI and delete a lot of deprecated APIs, which will have a significant effect on downstream projects. We’ve tried to prepare by marking the deprecations in 0.26 and updating downstream projects accordingly. But while this preparation means that most downstream projects “only need recompiling” this is something we want to do at the start of a release cycle, not at the end.

The argument for a 0.27 release is that there is functionality we want to release and that this can be done without the disruption of an ABI break. So even if we don’t release 0.27 for 17.04 we may well do so once 17.10 is “open” in order to make this work available for Unity8 developers to use.

Either way, sometime early in the 17.10 cycle we’re going to release Mir 1.0. This will clear the way for Mir support in Mesa and Vulkan.

Choosing a backend

I got drawn into a discussion today and swiftly realized there is no right answer. But there should be!

The question is deceptively simple: Which order should graphics toolkits probe for backends?

My contention is that the answer is: “it depends”.

Suppose that I’m running a traditional X11 based desktop and am testing with a new technology (obviously Mir, but the same applies to Wayland) running as a window on top of it. (I.e. Mir-on-X or Wayland-on-X)

In this case I want any new application to *default* to connecting to the main X11 desktop – I don’t want my test session to “capture” any applications launched normally.

Now suppose I’m running a new technology desktop that provides an X11 socket as a backup (Xmir/Xwayland). In this case I want any new application to *default* to connecting to the main Mir/Wayland desktop – only if the toolkit doesn’t support Mir/Wayland should it connect to the X11 socket.

Now GDK, for example, provides for this with GDK_BACKEND=mir,wayland,x11 or GDK_BACKEND=x11,mir,wayland (as needed). But that is only one toolkit: OTTOMH Qt has QT_QPA_PLATFORM and SDL has SDL_VIDEODRIVER. (I’m sure there are others.)

What is needed is a standard environment variable that all toolkits (and other graphics libs) can use to prioritize backends. One of my colleagues suggested XDG_TOOLKIT_BACKEND (working much the way that GDK_BACKEND does).

That only helps if all the toolkits take notice. Is it worth pursuing?

MirAL 1.3

There’s a new MirAL release (1.3.0) available in ‘Zesty Zapus’ (Ubuntu 17.04) and the so-called “stable phone overlay” ppa for ‘Xenial Xerus’ (Ubuntu 16.04LTS). MirAL is a project aimed at simplifying the development of Mir servers and particularly providing a stable ABI and sensible default behaviors.

Unsurprisingly, given the project’s original goal, the ABI is unchanged.

The changes in 1.3.0 fall are:

Support for “workspaces”

This is part of the enabling “workspaces” for Unity8 desktop. MirAL doesn’t provide fancy transitions and spreads, but you can see some basic workspace switching in the miral-shell example program:

$ apt install miral-examples
$ miral-app

There are four workspaces (corresponding to F1-F4) and you can switch using Meta-Alt-[F1|F2|F3|F4], or switch taking the active application to the new workspace using Meta-Ctrl-[F1|F2|F3|F4].

Support for “previous window in application”

You can now use Alt-Shift-` to switch to the previous in an application.

miral-shell adds a background

miral-shell now uses its background for a handy guide to the available keyboard shortcuts.

Bug fixes

Two bug fixes related to shutdown problems: one deals with a possible race in libmiral code, the other works around a bug in Mir.

  • [libmiral] Join internal client threads before server shutdown (LP: #1668651)
  • [miral-shell] Workaround for crash on exit (LP: #1667645)

miral-workspaces

“Workspaces” have arrived on MirAL trunk (lp:miral).

We won’t be releasing 1.3 with this feature just yet (as we want some experience with this internally first). But if you build from source there’s an example to play with (bin/miral-app).

As always, bug reports and other suggestions are welcome.

Note that the miral-shell doesn’t have transitions and other effects like fully featured desktop environments.

MirAL 1.2

There’s a new MirAL release (1.2.0) available in ‘Zesty Zapus’ (Ubuntu 17.04) and the so-called “stable phone overlay” ppa for ‘Xenial Xerus’ (Ubuntu 16.04LTS). MirAL is a project aimed at simplifying the development of Mir servers and particularly providing a stable ABI and sensible default behaviors.

Unsurprisingly, given the project’s original goal, the ABI is unchanged.

Since my last update the integration of libmiral into QtMir has progressed and libmiral has been used in the latest updates to Unity8.

The changes in 1.2.0 fall are:

A new libmirclientcpp-dev package

This is a “C++ wrapper for libmirclient” and has been split
from libmiral-dev.

Currently it comprises RAII wrappers for some Mir client library types: MirConnection, MirWindowSpec, MirWindow and MirWindowId. In addition, the WindowSpec wrapper provides named constructors and function chaining to enable code like the following:

auto const window = mir::client::WindowSpec::
    for_normal_window(connection, 50, 50, mir_pixel_format_argb_8888)
    .set_buffer_usage(mir_buffer_usage_software)
    .set_name(a_window.c_str())
    .create_window();

Refresh the “Building and Using MirAL” doc

This has been rewritten (and renamed) to reflect the presence of MirAL in the Ubuntu archives and make installation (rather than “build it yourself”) the default approach.

Bug fixes

  • [libmiral] Chrome-less shell hint does not work any more (LP: #1658117)
  • “$ miral-app -kiosk” fails with “Unknown command line options:
    –desktop_file_hint=miral-shell.desktop” (LP: #1660933)
  • [libmiral] Fix focus and movement rules for Input Method and Satellite
    windows. (LP: #1660691)
  • [libmirclientcpp-dev] WindowSpec::set_state() wrapper for mir_window_spec_set_state()
    (LP: #1661256)

mircade-snap

mircade, miral-kiosk and snapcraft.io

mircade is a proof-of-concept game launcher for use with miral-kiosk. It looks for installed games, works out if they use a toolkit supported by Mir and allows the user to play them.

miral-kiosk is a proof-of-concept Mir server for kiosk style use. It has very basic window management designed to support a single fullscreen application.

snapcraft.io is a packaging system that allows you to package applications (as “snaps”) in a way that runs on multiple linux distributions. You first need to have snapcraft installed on your target system (I used a dragonboard with Ubuntu Core as described in my previous article).

The mircade snap takes mircade and a few open games from the Ubuntu archive to create an “arcade style” snap for playing these games.

Setting up the Mir snaps

The mircade snap is based on the “Mir Kiosk Snaps” described here.

Mir support on Ubuntu Core is currently work in progress so the exact incantations for installing the mir-libs and mir-kiosk snaps to work with mircade varies slightly from the referenced articles (to work around bugs) and will (hopefully) change in the near future. Here’s what I found works at the time of writing:

$ snap install mir-libs --channel edge
$ snap install mir-kiosk --channel edge --devmode
$ snap connect mir-kiosk:mir-libs mir-libs:mir-libs
$ sudo reboot

Installing the mircade-snap

I found that installing the mircade snap sometimes ran out of space on the dragonboard /tmp filesystem. So…

$ TMPDIR=/writable/ snap install mircade --devmode --channel=edge
$ snap connect mircade:mir-libs mir-libs:mir-libs
$ snap disconnect mircade:mir;snap connect mircade:mir mir-kiosk:mir
$ snap disable mircade;sudo /usr/lib/snapd/snap-discard-ns mircade;snap enable mircade

Using mircade on the dragonboard

At this point you should see an orange screen with the name of a game. You can change the game by touching/clicking the top or bottom of the screen (or using the arrow keys). Start the current game by touching/clicking the middle of the screen or pressing enter.

MirAL 1.0

There’s a new MirAL release (1.0.0) available in ‘Zesty Zapus’ (Ubuntu 17.04) and the so-called “stable phone overlay” ppa for ‘Xenial Xerus’ (Ubuntu 16.04LTS). MirAL is a project aimed at simplifying the development of Mir servers and particularly providing a stable ABI and sensible default behaviors.

Surprisingly, given the project’s original goal, the ABI is changed. This allowed us to address a couple of minor issues and the timing seemed good as downstreams are faced with Mir-0.25 moving some necessary APIs from libmircommon to the more ABI stable libmircore.

The changes in 1.0.0 are:

  1. The default movement of child windows can be overridden by the window management policy;
  2. A new “miral-app” script that runs the miral example servers as an application on an existing desktop;
  3. Bug fix LP: #1646431 “Examples fail to start under Unity8”;
  4. Bug fix LP: #1646735 “[miral-shell –window-manager tiling] windows are not correctly constrained to tiles”; and
  5. A couple of deprecated APIs have been removed.

Mircade

Mircade

I’ve been playing with the “kiosk” concept implemented by miral-kiosk. Kevin Gunn and Alberto Aguirre have been using it to demonstrate Mir snaps (kg’s blog) so I decided to join the fun.

Mircade is a very basic kiosk-launcher for whatever games are installed on a system. It tries to work out whether the game will run natively on Mir and, if not, will try running them on Xmir (if installed).

To play, you need the latest miral-examples and libmiral-dev installed. You can “apt install miral-examples” from Zesty archive/Xenial “stable phone overlay” PPA, or build it from source on Xenial or later.

$ sudo apt install miral-examples libmiral-dev mir-graphics-drivers-desktop xmir

Once you have that sorted, Mircade is available from github. It has a few dependencies (I’ve tried to list them, but have probably missed one).

$ git clone https://github.com/AlanGriffiths/mircade.git
$ sudo apt install libfreetype6-dev libboost-filesystem-dev libboost-system-dev cmake
$ cd mircade/
$ cmake .
$ make
$ miral-desktop -kiosk -launcher ./mircade

Navigation is by arrow keys (left/right) and selection by Space or Enter. When your game exits you return to the mircade launcher.

Not all games work perfectly on Mir (yet):

  • Most of the GTK based games (like gnome-chess) run, but sometimes fail to “fullscreen”;
  • SDL2 based games (like 7kaa) have a tendency to segfault on exit; and,
  • X11 based games using Xmir may or may not work.

Have fun!