Divergence
   =========


   Err, I mean the Ubuntu's Convergence feature. As you may know, the
   Ubuntu developers declared that in the next few months (or years) there
   will be no new release of the Ubuntu Touch nor new device. They wish to
   finish the Unity 8 and the transition to different package format
   first. They even decided to stop the Ubuntu Touch development (no Over
   the Air updates) and only continue to fixing of critical bugs. To me,
   it sounds like preparation to a demise. But I may be wrong.


   Anyway, it means that the current state of the Ubuntu Touch will be
   frozen for a long time. So now it is possible to assess the usability
   and features of the platform, including their most proposed feature,
   the Convergence.

   The Convergence is an approach which should allow to use one
   application (with one source code) on several screen sizes - on a phone
   (or tablet) screen outside the office and on a big monitor when the
   device is on the desktop. It sounds good but it requires to have
   newly-written programs (or at least their GUI) which have to use the Qt
   5.x library.

   In reality, there is little such apps: many older programs are written
   with use of different toolkits (the older Qt versions, the Gtk+ or even
   the Motif and the Xaw/Athena or something even more rare). As the
   canonical know that many of widely used Linux programs will not be
   ported to the Qt5 anytime soon, they decided to allow use of "normal"
   X11 programs on the Ubuntu Touch. It's not that easy as there is no X11
   server. The modern display server used here needs to have an X11
   emulation layer to make use of these applications possible. The second
   issue is the act that Ubuntu Touch is more close to the Android than to
   the normal Unix system. All applications run sandboxed and there it no
   simple mechanism to communicate between them. And, of course, they do
   not use normal filesystem access - most of them cannot access files
   outside the application directory. There is mechanism to share data but
   it's limited to pre-defined file types.

   Anyway, now it is possible to install X11 applications from Ubuntu
   repositories via a wrapper to the apt. Not all applications works and
   the world of X11 applications in in some manner independent on the rest
   of theUbuntu Touch environment. Fortunately, they share the access to
   the ~/Documents directory and it is possible to open LibreOffice file
   types via the standard system mechanism.

   There are some issues:
     * improper work with dialog windows (they are ugly and strangely
       placed but otherwise they are fully accessible and functional)
     * some applications don't start due to emulation bugs - the gVim, for
       example
     * some stuff (screen, tmusx,..) don't work tue to access rights
     * not everything is available in repositories (the Paraview)
     * everything uses basic themes o the toolkits so everything is ugly
     * it the program is started from a terminal emulator (one cannot use
       the default Terminal program here) then the started app replaces
       the emulator window - there is a small ugly bar with a tinny arrow
       to swith it back but it is unconvenient and it makes uneasy use
       applications like the GNU Octave
     * the X11 environment is available only for devices with an external
       screen output so Aquaris phones are out of the game (he M10 tablet
       is supported, though)
     * the configuration possibilities are pretty limited - no virtual
       desktops, no custom keyboard shortcuts
     * many applications do not remember their previous sizes - they start
       in the form of small window in the top left edge of the screen - I
       can understand that third-party programs are doing this but the
       default launcher has also this problem (!); some programs are OK
       (the WWW browser, for example)
     * there are problems with the output to the external monitor - on the
       M20 tablet only 1920x1080 screens works, smaller ones don not

   Thus, this Convergence thing is just partially usable. I can imagine
   that one can use the Ubuntu Tablet with an external keyboard and mouse
   as an lightweight notebook replacement for some easy work. I cannot
   imagine that someone can be able to use this as a desktop replacement,
   even with a proper screen, a keyboard and a mouse (I do have them: a
   1920x1200 HP LCD - only 19200x1080 us used, thought, a Lenovo keyboard
   and a Lenovo mouse). The work is obviously easier than on the
   Android/iOS "desktops" but not that much.

   The more positive fact is that one can use here Tcl/Tk programs, old
   Unix programs which use in the Motif or the Xaw3D toolkit (XFig, Gv),
   even these that use OpenGL and it is possible to run remote
   [1]X11 program. But only when the mouse and the keyboard is attached.
   In fact, the mouse is not necessary (even it's makes use of such apps
   much comfortable) but the keyboard is mandatory - only specially
   modified X11 apps can use the touch keyboard and even these may some
   issues (it looks like the LibreOffice is OK but the Firefox is not - it
   cannot access some input fields with the touch keyboard).

   So the result is that such thing is usable but it there is still no
   phone/tablet which can be magically transformed into desktop just by
   connecting it a big screen and the input devices... :-(


   P.S. I wrote this text completely on the Aquaris M10 tablet to prove my
   conclusions.