News

2014-02-09 

I have been particularly discreet for several months. It is not a sign of disinterest in this project, quiet the opposite.

In fact as you imagine, many users are requesting us a tablet version of GCompris and I tried to evaluate the different technical possibilities to bring GCompris to this world. Sadly, Gtk+ the core technology we are based on does not provide any easy way to run on tablet.

The main requirements for me was to be able to have a single code base that would let us target the main desktops and the main tablets.

After looking at different options, I settled on Qt Quick. It is a modern toolkit based on a novative descriptive language called QML that let you describe the user interface, javascript that complement it to code the game logic. It is also possible to develop the non graphical part of the application in C++ with Qt.

It is based on an OpenGL scene graph, we can create shader and particles to make graphical effects and do smooth animations.

In order to validate this choice, I did a prototype and this convinced me that it was a pertinent choice for GCompris. Even if this is a new technology, the learning curve is acceptable, with very few code you can create a very good looking activitiy. In my test it takes about half the lines of code to make the same activity in Qt Quick than we used to in Python and we get a better graphical quality.

The bad news is that it is not compatible with the current version of GCompris and it requires a full rewrite. All we can keep is the game logic and tuning, the texts, the translations, the graphics and the sounds.

I just published the GCompris-qt version on GitHub and updated our development page to give some starting points to build it yourself.

For those who don't want to compile it, you can look at the little video.

Another important point, since this is not based on Gtk+ this new version cannot be hosted by Gnome as we used to do. Therefore we cannot participate in the Google Summer of Code under the Gnome umbrella. I thus registered GCompris for this year session of GSoC and Frederico Goncalves Guimaraes accepted to be the official co-mentor.

If you are interested in helping GCompris, I encourage you to learn Qt Quick and to help port some activities. This is a good opportunity to learn a new technology while doing something useful. I still have to refine and document the process to create a new activity but it is not very complex.

GCompris on Gtk+ has been around for 14 years. It is true that the migration will take time, probably several years but this is something we have to do if we want to stay relevant in the coming years.

Bruno.

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