Jun 10, 2010

Map Updates

I recently made a number of improvements to osm-gps-map, the easy to use mapping widget. The motivation for these came at the request of the foxtrotGPS developers (foxtrotGPS is a community developed fork of TangoGPS). These changes enhanced the API for adding images and tracks to the map, and in addition allowed me to clean up the basic API making it easier to use for the common case. But, there is more, especially relevant to Gtk+/GNOME 3.0.

osm-gps-map demo application

Jan 22, 2010

Misc Hacking

I had two days off while I moved offices, so I got a chance to catch up on my backlog of random hacking.


I released osm-gps-map v0.5.0 which adds a few new features (such as keyboard navigation) but also contains many bugfixes and performance improvements. Check the release notes for more information. The next item on the TODO is merging the OSD/layers branch.


I released Conduit 0.3.17 which was long overdue. Mostly a bugfix release and updating to new API. The Conduit homepage has also moved to live.gnome.org. Progress on Conduit is a bit slow at the moment, it does everything I want it to (I have a budget cellphone so phone synce does not interest me), and is pretty stable. I have some SOC work I would like to merge, but basically I am looking for developers and inspiration...

PyGTK for Windows

I finished off the fixes to build correct PyGTK+ installers on windows, hopefully closing bug #589671. I uploaded new installers with the fixes people have reported. I expect these installers to become the 'final' installers at some point. Feedback welcome.

PyGTK Hacking

I wanted to play with the new client side windows work in Gtk+, so I ported the effects gtk-demo to Python. This required a bit of ctypes magic to access the new API (good), and some more ctypes magic to interact with new signals that appears to have unfriendly prototypes (not so good, bug filed here).

PyGTK example using client side windows

Jan 11, 2010

Gtk+ Map Widget

It has been a long time between blogs. I thought I should talk about the piece of software that has been responsible for the most emails in my inbox over the last few days - osm-gps-map, the Gtk+ based map widget. What started as a widget for use in one small application of mine has grown considerably.

  • I recently released 0.4.0, a bugfix release.

  • I created a mailing list, if you are a user or interested osm-gps-map, them please join.

But I thought I should take some time to highlight some of the most interesting users of osm-gps-map, particualry those users on the Maemo platform.

Maep, OSM2Go and GPXView (by Till Harbaum)

Maep Screenshot Maep



BrainStorm (by Adam Boggs)

  • BrainStorm is a storm chasing application that plots your track, and overlays current radar and severe warning imagery on the map.

Brainview eCoach

  • eCoach is an application for recording and managing sport activities with Nokia N900, it records heart rate data from various monitors, and plots your path on the map as you exercise.



  • With the help of these users, the future of osm-gps-map looks very positive.

  • I am currently working on merging Till's improvements to master to discourage people from copying osm-gps-map source into their application.

  • If you are a user of osm-gps-map and I have forgotten you then I am sorry. Please contact me and join the osm-gps-map mailing list.

Apr 23, 2009

Map Widget Release

I made a new April resolution to start blogging reguarly again. The first step of that long journey begins now.

OpenStreetMap GPS Mapping Widget - 0.3

I just released v0.3 of osm-gps-map, the easy to use Gtk+ mapping widget. Highlights for this release include;

  • A new major contributor, Alberto Mardegan, who worked on many of the new features of this release. Thanks a lot Alberto!

  • Draw map tracks with Cairo by default.

  • Interpolate between zoom levels while waiting for a tile to download.

  • Stop using GET_PRIVATE, and cache priv* for performance.

  • Keep an extra border of images offscreen for smoother scrolling at the edges of the map.

  • Keep the last N tiles in memory to improve render performance (previously they were loaded from disk)

  • Add some new api; osm_gps_set_center, osm_gps_map_scroll.

Conduit Hacking

Hacking on Conduit continues, with much happyness for two reasons;

  • GNOME has moved to git! Wahoo! I owe the sysadmin team many beers, except for Jc2k who I know could not handle them anyway.

  • Conduit got a SOC project, congratulations Alexandre!

  • Work is ongoing to merge in the new configuration and settings serialization code.

  • More on this later, I promise...

Jan 23, 2009

Some More Software

As was the theme of yesterdays post, here comes some more software that I have hacked on recently and can now be found on Github.

osm-gps-map osm-gps-map is a Gtk+ widget (and Python bindings) that when given GPS co-ordinates, draws a GPS track, and points of interest on a moving map display. It Currently supports a number of different mapping sources;

  • openstreetmap (default)

  • openaerialmap

  • maps-for-free

  • satellite maps from a number of proprietary providers

It also has the following features

  • Intelligent caching of maps, including the ability to request a specific area of the map to be cached ahead of time

  • Recording of points of interest on the map (and the ability to add arbitary pixmaps at those points

  • Automatically draws a GPS track (a line showing the history of past added points)

  • Automatic centering on new GPS points

  • Support for multiple other tracks of co-ordinate points

  • Adjustable Zoom

  • Includes a comprehensive example

  • Simple, flat API

I have been running it on a number of embedded boards (beagleboard, Overo) for some commercial work I have been doing (hence the minimal dependencies). For those Planet GNOME readers, It is kind of like libchamplain but without the Clutter part.

facebook-notify Reaction to the posting of my Facebook notifier for GNOME was positive, and I made a few quick fixes to remove some crasher bugs.

The biggest source of frustration at this point is that libwebkitgtk segfaults, upon destroy, almost every time it encounters a page that requires the initialization of an NPAPI plugin. Disabling plugins using the built in BrowserSettings object does not seem to have any effect.

Is there a RoadMap or any plans for an updated WebKitGtk release before the next round of distro updates?

Conduit I have been hacking on Conduit a bit over the last few days, and thanks to Julien Lavergne we now have updated builds for Intrepid and Jaunty. Julien also packaged a trunk snapshot (and set up the infrastructure to allow easier updating of such snapshots). I recommend all users of Conduit add our PPA.

Aug 23, 2008

Blog as Noticeboard

Summer of Code This has now finished, and I am really happy with how it went. I was able to complete a Python binding to libsyncml. This was done with the help of Pybindgen, which aside from a few quirks, performed admirably. Expect this to become the premier tool to automatically create python bindings to C/C++ libraries. The binding still contains too many bugs to be considered usable in Conduit trunk (read: crasher bugs) but I can see the light at the end of the tunnel.

Alexandre Rosenfeld was also successful in his Conduit Summer of Code project. He contributed audio and video support for the iPod, and a comprehensive audio/video converter/trans-coder using python-gstreamer. The iPod support seems quite comprehensive, and the converter component is a necessary component of the Conduit architecture for our future plans.


Conduit While it may look like I have been dormant at Conduit hacking, work has been ongoing in a number of branches. Unfortunately I still cannot push these branches to bzr-playground.gnome.org because the SSH keys from GNOME have not been synced across in over two weeks, leaving me locked out.. The GIO port is now working (with the exception of gvfs bug #547133, which I would dearly like someone to commit the fix for).

One of the major tasks necessary for the GIO port was the isolation of the platform specific parts, such as GConf, and GnomeVFS. One thing that fell out of this work is that Conduit now works on Windows. With no (~10 lines) code changes. Amazing really. It should be noted that this is not actually using GIO on windows, it is using a pure Python File class implementation.

Conduit running on Windows Conduit can haz Windows!

I am not really serious about maintaining this port, but it shows what is possible. If someone wants to hack on this I can point them to the necessary places. But basically you will need

I have also moved over to using PyWebkitGtk for the Conduit Web browser. They just made a 1.0 release, and I would really like it if those responsible for packaging Conduit, could please also package PyWebkitGtk, and ensure that it gets the necessary exceptions so that it is accepted into the appropriate distributions. Words cannot express how happy I am to be rid of gtkmozembed. It is a shame that webkitgtk was not accepted as an external dependency for GNOME 2.24, as this now makes getting things like pywebkitgtk into distributions a royal PITA.

Openstreetmap GPS Widget Some time ago I mentioned the osm-gps-map widget that I have been working on, semi-related to my PhD. I just made the inaugural 0.1 release. This widget basically lets one easily write moving-map display widgets very easily, showing points of interest, and multiple gps paths atop of tiles fetched from openstreetmap, or other mapping providers. It started as a port of Tango GPS, and can now basically do everything that application did, but behind a simple GObject API. Python bindings are also provided

Openstreetmap GPS Gtk Widget


May 21, 2008


Frantic would be how I described my last two weeks. I have had very little free time to work on Conduit. Everything seems to have come at once!


  • I have been playing with barpanel, a very functional GNOME panel replacement.

  • Grape is certainly an interesting UI/desktop mock up. If I had infinite spare time I migh have a hack on it, as an excuse to play with Clutter.

  • Props to Jan Bodnar for his excellent Gtk+ and Cairo tutorials.

  • My (bad) experiences with Ubuntu 8.04 can be best described by the following picture.. Firefox crashing

Openstreetmap GPS Mapping Widget

Somewhat tangentially related to my PhD, I have been hacking on a simple Openstreetmap GPS mapping/display widget. Basically because after investigating all the existing mapping programs on linux, none of them supported openstreetmap/openaerialmap and were able to be easily embedded.

OSM GPS map widget

It's basically a port of tangoGPS (by Marcus Bauer) to libsoup and considerable clean-up. The whole thing is now hidden behind a derived GtkDrawingArea with a nice simple 4 function api (other parameters such as zoom, lat, lon, are accessible as gobject properties)

  1. set_map_center(double lat, double lon, int zoom)

  2. add_gps_point(double lat, double lon)

  3. add_roi(double lat, double lon, GdkPixbuf *pixbuf)

  4. get_bouding_box()

Things like double click, map dragging, scroll to zoom, etc are all handled automatically as you would expect. It caches downloaded tiles and it's pretty much complete at this point. I hope to be able to post code soon.