Nodes proceeding hierarchies are not centered

[dsteinbach-ep]

As shown in the screenshot, im not sure which setting can address this but any node that proceeds a hierarchy node seems randomly placed with a left or right offset.

My layoutOptions (for all nodes)

{
  'elk.algorithm': 'layered',
  'elk.direction': 'DOWN',
  'elk.hierarchyHandling': 'INCLUDE_CHILDREN',
  'elk.layered.nodePlacement.favorStraightEdges': 'true',
  'elk.layered.spacing.baseValue': '50',
  fixedAlignment: 'BALANCED',
}

Removing the elk.hierarchyHandling=INCLUDE_CHILDREN setting aligns those nodes correctly but causes preceding nodes of hierarchies to be rendered side-by-side to the hierarchy.

[soerendomroes]

Hi, could you create a minimal example using elklive?
https://rtsys.informatik.uni-kiel.de/elklive/elkgraph.html

[dsteinbach-ep]

Sure! As you can see n4 is not centered below n2 (nor is it centered in relation to n3). n4 appears more than just "aligned left" as well - there seems to be some negative left margin added. Changing n1->n3 to n1->n2 instead helps align everything correctly, however, that's not the requirement im building for :/

Furthermore, removing 'elk.hierarchyHandling': 'INCLUDE_CHILDREN' aligns n4 correctly, however, n1 is then rendered horizontally in relation to n2.

https://rtsys.informatik.uni-kiel.de/elklive/json.html?compressedContent=N4KABGCWAmBcYCIBOB7FAXBAacYA2AhgJ4oCu6A8gA7qQoB2AzvMGAOQF4DmKSk6ACwC2beG0JEApkknQ2WdpLwBrAHTRIMgMa0Go9gBEKAdQBy8xStUDI0gki0CiACQL1oeSPS762ASVMAYQAZAFUDAFEAfUDnP2CDACUI8zAAXxwIR0g8aBl6eABtXAhWGHgEegBGbDAAdxhBeABmAAYFAUlILgF0Ftb0zIgwMrhEegAmWoboJrA2jq6evvn2sGzc-KKS4dGK+mbpxoF+xe7e-sGdgF0r4ZGoMcqAFiPZk9Wz5cuM3Guh2RcSTMMDFe57RCSGoKRhkBzAorjGpgf5gdD2IHoEGFcaHFF3XaPCqSKYwuFaBGg8ZTFEKdFITHY8avfG-CDXEBpIA

[dsteinbach-ep]

Adding 'elk.layered.nodePlacement.strategy': 'SIMPLE' to the root node and any grouping nodes did the trick.

https://rtsys.informatik.uni-kiel.de/elklive/json.html?compressedContent=N4KABGCWAmBcYCIBOB7FAXBAacYA2AhgJ4oCu6A8gA7qQoB2AzvKBBAOQF4DmKSk6ABYBbdvHaEiAUyRTo7HGzDspeANYA6aJFkBjWgzHKAIhQDqAOQW4OqzYMgyCSXYKIAJAvWh5I9bkbsAJIWAMIAMgCqxgCiAPqh7kHhxgBKMVaKbCrqGpIychr0KNBSAAqEulLCUvToGozoSAToUtxEgQDKQQCyZeEx7DZgAL5ZrpB40LL08ADaw8BQcIj0AIzYYADuMELwAMwADFhgglKQ3ILoB4ejWRBLwxAw8Aj0AEybT9u7gjcn3zOFyu-zA30kZEoNDoTBY31suXysmgRRK5Uq1Vq9UazVa7S6vX6g3hdzAEymM3m3yWL1W+02O2gezARxOQMu1xZtzGwwAundFstXvQACwM36g9kgrkCiC8rJybhSZhgBZKGkrBBSDYnRhkFzK+arDZgeVgdDOJXoFVzOkIU2ytga15ST66-VVG2rT6mk4WpBWr1vMUOnlykAjIA

You may close this ticket if you like. Thanks.

[dsteinbach-ep]

Actually this issue still persists with a more complicated use case. Also, I cannot get north/south ports working correctly within group nodes. Example.

[soerendomroes]

Preserving the defined port placement of unconnected nodes is definitely something that we would consider doing.

For someone who wants to tackle this:
The issue lies in the separate connected components and possible how INCLUDE_CHILDREN adds elements to the same graph.
Additionally, if considering separate connected components, we cannot really be sure whether an edge to the outside does not cross the separate port that we want to align based on the configuration.

[dsteinbach-ep]

Thanks. Any suggestions for the issue where only north ports are being used in nodes within a group?

[soerendomroes]

@dsteinbach-ep What do you mean by that?
I guess since the layout direction is DOWN, NORTH is the default port placement side if no side is specified.