Sunday, 15 August 2010

Contributing to Shotwell


I use open source software every day on all the computers I own. In fact, outside of work environments where Windows is still predominant, very little of the software I use is closed source these days. As a result, I've wanted to contribute back to the community that has developed such great software by fixing bugs and implementing new features. However, I've found it a lot more difficult that I expected. To make any meaningful contribution, the project I would contribute back to had to be a piece of software that I used regularly. When I look at the ecosystem of software I use regularly, they are either written in C, a language that I haven't programmed in for 20 years (assuming the stuff I did at university actually counts) or they are extremely complex, or both.

Then, a few months ago, I got wind that one of the planned changes for Ubuntu 10.10 (Maverick Meerkat) was to replace the default photo management software: F-Spot was out, Shotwell was in. Photo management has been a sore spot of mine for ages on Ubuntu. None of the software that was available until now actually met my needs so I ended up not using any photo management software and doing everything through the file manager. Looking into it, it looked like Shotwell was the ideal opportunity for me to get a photo manager I liked. Shotwell uses Vala as a programming language, which I found intriguing and which I thought should be easier than C to get into.

Baby Steps

So I downloaded the source from the SVN repository, built the software and lo and behold, the build was actually easy and 10 minutes later I had a local version of Shotwell to play with. I then had a look at the source code and found it very easy to understand. So I thought: let's see if I can fix an easy bug!

For that experiment, I choose a bug that looked extremely easy: bug 1954 looked like the ideal candidate because it merely consisted in adding a line of information to an existing window in exactly the same way as the other lines already present in the window. And indeed, the fix was trivial. So I created a patch and uploaded it to the bug tracker.

What happened next was very important and is something that all community projects should be very attentive to: I got some feedback on my patch within a day, basically saying that the patch had now been committed to trunk with a minor modification. This is extremely important and is something the Yorba team, who produce Shotwell are very good at doing: all contributors are welcome and any contribution, such as suggestions or patches, are acknowledged very quickly. From a contributor's point of view, it means that you know that you can really participate and help the core development team improve their software.

More Complex Bugs

Quite chuffed by the outcome of my first bug fix, I decided to use Shotwell extensively and try solving more complex bugs. I eventually hit a significant issue with my SLR camera, which I duly reported in the bug tracker and which I decided to attempt to solve. It took a bit of time but I eventually got there and as a side effect actually solved another bug: result!

A Whole New Feature

By now completely sold on Shotwell, I wanted to do my bit so that it would be well received by Ubuntu users. In my mind, the most important thing was to ensure a smooth transition from F-Spot to Shotwell and indeed the migration was one of the major requested features in Launchpad and very high on the Yorba list too.

Implementing such a major feature can feel a bit daunting at first but, at the end of the day, integrating and migrating from weird and wonderful databases is something I get involved in on a regular basis in my day job so bringing that experience to Shotwell sounded like the way to go. And to be honest, the F-Spot database is extremely simple compared to some of the horrors I've faced recently.

It took a bit of time and I learnt a lot about Vala and the GObject library in the process. Thanks to the support from Jim and Adam from Yorba I got there in the end and finished the bulk of it in the middle of GUADEC. A few more extra tweaks were required but it's now in fairly good shape, ready to face the hordes of new users that Ubuntu will bring it.

There you go, that was my first major contribution to an open source project and I'm now hooked so will endeavour to contribute more.

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