Avoid overlap in edges over elements

[gee4vee]

We are investigating how to route edges so that they go around our elements, in this case these boxes that encapsulate input and output ports. So the edge going from test-da2:test_boolean to test_da1:test_boolean should look for a path around test-da2's box as well as other boxes along the way to the target.

I've looked into other possibilities like a different ELK layout algorithm but that seems to be broken. Also I saw a very old post about sprotty libavoid, but seems rather complicated and not sure if it's up to date.

Would a custom edge router be required for this? If so, how would the edge router implementation get access to all the other elements to calculate routes that go around them?

[martin-fleck-at]

Hi @gee4vee,

Yes, you would probably need a custom edge router implementation for that. There are basically two interfaces an edge router can implement. If you implement IMultipleEdgesRouter then your router is given all edges and the parent element so you can do a more "global" routing. Otherwise, edges are routed one by one. I think your best bet is to use an external library to properly calculate the routes. As you mentioned, I think the sprotty-routing-libavoid definitely has the right idea but I'm not sure how regularly it is maintained. However, it is just a thin layer wrapping the libavoid-js which is still regularly published.

In the CrossModel project we faced a similar problem and managed to improve the situation a lot by applying the idea of sprotty-routing-libavoid but using libavoid directly on the client-side with a custom edge router. We still use ELK on the server side to layout the Nodes but the routing is handled client-side. So feel free to have a look at how we did it there.

I hope this will help you get started.