@ouestware/graphology-layout-elk

OuestWare's Graphology Experiments - Layout ELK

A graphology connector to the elkjs layout engine.

It translates a graphology graph into ELK's graph format, runs an ELK algorithm (layered by default), and returns a LayoutMapping of each node to its position and box size.

Usage

import Graph from "graphology";

import { elkLayout } from "@ouestware/graphology-layout-elk";
import { applyLayout } from "@ouestware/graphology-layout-utils";

const graph = new Graph();
// ...populate the graph...

const layout = await elkLayout(graph, {
  // ELK options, forwarded as-is:
  layoutOptions: { "elk.algorithm": "layered", "elk.direction": "RIGHT" },
  // How to read each node's box size from the graph:
  attributes: {
    width: "width", // read from the "width" node attribute
    height: (node, attributes) => attributes.size * 2, // or extract it
  },
});

// Write x / y back as node attributes, and the box size as "w" / "h":
applyLayout(graph, layout, { width: "w", height: "h" });

Notes

• elkLayout is asynchronous (it returns a Promise).
• ELK positions boxes by their top-left corner: By default, the returned coordinates are node centers. Set center: false to keep ELK's top-left corners.
• The bundled elkjs engine runs on the main thread.