OuestWare's Graphology Experiments - Layout utils

Shared types and helpers to work with graphology layouts.

It defines the LayoutMapping type returned by the various layout packages in this repository (a mapping of each node to its coordinates), and provides applyLayout to write such a mapping back onto a graph's node attributes.

Usage

import Graph from "graphology";

import { type LayoutMapping, applyLayout } from "@ouestware/graphology-layout-utils";

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

// A LayoutMapping maps each node to at least { x, y }:
const layout: LayoutMapping = {
  a: { x: 0, y: 0 },
  b: { x: 1, y: 1 },
};

// Write x / y back as node attributes:
applyLayout(graph, layout);

Layouts may carry extra fields beyond x / y, and applyLayout can rename any field to a different node attribute:

const layout: LayoutMapping<{ x: number; y: number; width: number; height: number }> = {
  a: { x: 0, y: 0, width: 10, height: 20 },
};

// x / y are written as-is, while "width" / "height" are stored as "w" / "h":
applyLayout(graph, layout, { width: "w", height: "h" });

Notes

• LayoutMapping<T> is generic over the coordinates type, which must extend { x: number; y: number }.
• applyLayout uses mergeNodeAttributes, so it only overwrites the mapped fields and leaves other node attributes untouched.
• Fields left out of the rename mapping are written under their own key.