Earlier quoted context omitted.
It's a commercial project, I have updated my comment to make it clear. I would open source it if it was a sustainable option. In the past Gravit and Xara did try to use the open source model, but there was very little interest from the community to contribute.
There was heaps of community interest in Xara, but the company kept the key rendering engine component proprietary, which killed it.
[1] http://libregraphicsworld.org/blog/entry/stagestack-faces-de...