Pfthb

I'm trying to use ElkJS to calculate the layout for a family tree and getting pretty decent results. However, I can't seem to get the T-style intersections working.

Consider a family with 2 parents (P1, P2) and 3 children (P3, P4, P5). I added a fake node R1 with 1x1 size to which all other nodes are connected, and this is the ELK JSON I am using:

 "id": "root",
 "layoutOptions": 
 "elk.algorithm": "layered",
 "elk.direction": "DOWN",
 "elk.edgeRouting": "ORTHOGONAL",
 "elk.layered.mergeEdges": true
 ,
 "children": [
 
 "id": "P1",
 "width": 100,
 "height": 50,
 "layoutOptions": "elk.portConstraints": "FIXED_SIDE" ,
 "ports": [
 "id": "P1:e", "layoutOptions": "elk.port.side": "EAST" ,
 "id": "P1:w", "layoutOptions": "elk.port.side": "WEST" 
 ]
 ,
 
 "id": "P2",
 "width": 100,
 "height": 50,
 "layoutOptions": "elk.portConstraints": "FIXED_SIDE" ,
 "ports": [
 "id": "P2:e", "layoutOptions": "elk.port.side": "EAST" , 
 "id": "P2:w", "layoutOptions": "elk.port.side": "WEST" 
 ]
 ,
 
 "id": "P3",
 "width": 100,
 "height": 50,
 "layoutOptions": "elk.portConstraints": "FIXED_SIDE" ,
 "ports": [
 "id": "P3:n", "layoutOptions": "elk.port.side": "NORTH" 
 ]
 ,
 
 "id": "P4",
 "width": 100,
 "height": 50,
 "layoutOptions": "elk.portConstraints": "FIXED_SIDE" ,
 "ports": [
 "id": "P4:n", "layoutOptions": "elk.port.side": "NORTH" 
 ]
 ,
 
 "id": "P5",
 "width": 100,
 "height": 50,
 "layoutOptions": "elk.portConstraints": "FIXED_SIDE" ,
 "ports": [
 "id": "P5:n", "layoutOptions": "elk.port.side": "NORTH" 
 ]
 ,
 
 "id": "R1",
 "width": 1,
 "height": 1,
 "layoutOptions": "elk.portConstraints": "FIXED_SIDE" , 
 "ports": [
 "id": "R1:n", "layoutOptions": "elk.port.side": "NORTH" ,
 "id": "R1:s", "layoutOptions": "elk.port.side": "SOUTH" 
 ]
 
 ],
 "edges": [
 "id": "E1", "sources": [ "P1:e" ], "targets": [ "R1:n" ] ,
 "id": "E2", "sources": [ "P2:w" ], "targets": [ "R1:n" ] ,
 "id": "E3", "sources": [ "R1:s" ], "targets": [ "P3:n" ] ,
 "id": "E4", "sources": [ "R1:s" ], "targets": [ "P4:n" ] ,
 "id": "E5", "sources": [ "R1:s" ], "targets": [ "P5:n" ] 
 ]

Expected result:

Actual result:

I'm implementing an app that draws arbitrary trees from user input. Therefore, the best solution should not rely on explicit port side specification.

It it possible to fix this?

P. S. Useful link to a visualizer to play around with the JSON: https://rtsys.informatik.uni-kiel.de/elklive/json.html