At the end of the day, I found that plantuml is the most suitable tool for this.

Graphviz dot is interesting, but it doesn't feel natural to make class diagram with it, or at least it's less handy... I could bring several arguments to support this, but it's not the topic.

Everybody wanting to try itself is welcome, but, *I* can take the commitment to maintain it over the years.

Here are the 3 svg files witch are my last proposals for the moment: