Manhattan Router - Change bend point?

[jmenzies12]

Hey there,

I want to override the Manhattan router to ensure that the bend point is placed closer to the target node.

At the moment it's 50% of the distance between the source and target, which results in some overlap the more nodes I add (comment nodes in elk layout, are placed on the left and right of the source instead of below). You can see an example below.

I've already overridden the router in order to add rounded corners. But my attempts to change the bend point from 50% to 10% have failed.

Wondering if anyone has a better understanding of how this works?

[martin-fleck-at]

Unfortunately, I also do not have any deeper understanding of how the Manhattan edge router works. I'd have hoped that setting the standardDistance or adapting the calculateDefaultCorners is enough. Maybe @planger or @rsoika have an idea as I know that they did some great routing work.

[jmenzies12]

No worries, it turns out calculateDefaultCorners was indeed the correct place to adapt. I was wrongly looking at the parts that use "manhattan-50%" but it was the code that divides by 2 that was what I should have been adjusting, for example:

corners.push({ x: (startPoint.x + endPoint.x) / 2, y: startPoint.y });

[rsoika]

Hi @jmenzies12,
this is interesting. Yes we have overwritten the Manhattan router in our Open-BPMN project too.
The effect you show here is something I do not have seen before. Maybe you can simply fix this if your view places an invisible rectangle outside of the ellipse. This - I guess - will fix your problem.
You can also take a look into our Manhattan Implementation (https://github.com/imixs/open-bpmn/blob/master/open-bpmn.glsp-client/open-bpmn-glsp/src/bpmn-manhattan-router.tsx). It adds also the rounded corners and did some tricks to prevent the routing algorithm to recalculate the complete route in some cases.
Play around with our demo. I am still interested to improve the routing algorithm in general. Maybe you have additional ideas?