Re: Proposing libchamplain as an external dependancy for GNOME 2.28

[John Stowers <john stowers lists gmail com>]

On Mon, 2009-05-04 at 22:37 -0400, Pierre-Luc Beaudoin wrote:
> Hi,
> 
> I would like to propose libchamplain as an external dependency to GNOME
> 2.28.  If you never heard about this project, it is a Clutter based map
> widget for your application.  It currently uses downloaded image tiles
> as map data but there is a Google Summer of Code project to render the
> tiles locally.  More information available at: 
> http://projects.gnome.org/libchamplain

Hi

As the maintainer of osm-gps-map [1], a non-clutter mapping library with
comparable features, I support libchamplain's proposal.

I do not intend to add clutter support to osm-gps-map, it will remain a
Gdk/Cairo only library as its intended, and my current, use of it is on
embedded devices with no OpenGl support. Clutter is the new cool, so I
support all ways to get this into the platform.

However, looking over the libchamplain API (quickly, sorry if I
mis-characterize something) I have a few comments

* It is good to see you have added support for specifying map uri's. I
would also like to see you support quadtree encoding, and randomization
of hosts. See osm-gps-map for what I mean...
* Where is the simple API? It seems like quite a few lines of code are
required to get something to show. In osm-gps-map one can write

map = osm_gps_map_new() 

or

map = g_object_new (OSM_TYPE_GPS_MAP,
                           "repo-uri","http://www.bla.com,
                           "tile-cache",cachedir,
                           "tile-cache-is-full-path",TRUE,
                           "proxy-uri",g_getenv("http_proxy"),
                           NULL);

and they are done. If this sort of scheme is not possible because
libchamplain returns a Clutter actor, what about adding a call

map = libchamplain_new_gtk_widget(xxx)

Which at least returns the widget wrapped already setup in a Gtk+
widget. Is this possible or does that add some dependecy to clutter-gtk?

* What is the sqlite dependecy for? Cache? Did you feel that using a
database for cache was a performance benefit? In osm-gps-map we use an
in memory cache of the last N tiles + a border around what is already
showing, and just load the rest of the tiles from disk. Performance of
that approach is more than sufficient (on any of the embedded targets I
have tried, for example)

Regards

John

[1] http://nzjrs.github.com/osm-gps-map/


> 
> Libchamplain 0.3 (a development release) has just been released.  A 0.4
> stable release will be made before or in sync with GNOME 2.28.
> libchamplain follows Clutter numbering and API/ABI stability plan.
> Since it is a young project, errors in the API are corrected in the next
> even release until maturity is achieved and 1.0 is released.
> 
> Libchamplain would not introduce any new dependencies.  It currently
> depends on Clutter 0.8 but will be ported to Clutter 1.0 as soon as it
> is announced. Or depandancies include: libsoup(-gnome), cairo, sqlite
> and Gtk+.  It doesn't depend on deprecated libraries for Gnome 3.0.
> 
> libchamplain already use a lot of the GNOME infrastructure: bugzilla,
> mailing list, wiki and web hosting.  Migrating the git repository from
> gitorious to git.gnome.org is planned. Releases are stored on
> libchamplain.pierlux.com for now but it is also planned to move to
> GNOME.
> 
> libchamplain is already used by an EOG-plugin to display where an image
> has been taken.  There are pending branches for Empathy (being reviewed,
> to be optionally available for 2.28) to display a map of where your
> contacts are.  There is also an embryonic plug-in for F-Spot.  Other
> non-GNOME applications are using it too but none have made releases
> using it so far.
> 
> libchamplain has bindings for Perl, Python, C# and C++.  You can find
> packages (or work has started) on Debian, Ubuntu, Gentoo, ArchLinux,
> RedHat and OpenSuse. There is a port to FreeBSD.
> 
> While libchamplain isn't integrated with any of the GNOME sub-projects,
> it shouldn't feel alien to them either.  There is little i18n to be
> done, no user documentation needed and I bugtriage myself.  There has
> been some talk about A11y, but these plans will have to wait until the
> SoC is over. Developer documentation is very important and that's why a
> full API reference is available:
> http://libchamplain.pierlux.com/doc/unstable/
> 
> libchamplain would contribute to improve the User Experience desired in
> GNOME 3.0 by bringing blingy map information to the desktop.  Teamed
> with GeoClue you get a geolocation framework to build tomorrow's
> location aware applications.  7 SoC projects were submitted in regard to
> geolocation in GNOME this year only (2 were accepted, 5 were releated
> directly to libchamplain).
> 
> libchamplain is available under LGPL 2.1.
> 
> The project started in August 2008 and has enjoyed a nice growth since.
> There is a good community starting to build on the IRC channel and we
> can count 16 different contributors to the code. See
> https://www.ohloh.net/p/libchamplain for more interesting stats.
> 
> In this email, I hope I made my case that libchamplain could be a nice
> addition to the GNOME family.
> 
> Best Regards,
> 
> Pierre-Luc Beaudoin
> Maintainer of libchamplain
> 
> 
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