Limits

Some layouts refuse some graphs and throw from run(). Catch the error and pick another layout:

import cytoscape from "cytoscape";
import graphtyCytoscape from "@graphty/cytoscape-extensions";

cytoscape.use(graphtyCytoscape);

const cy = cytoscape({ headless: true });
await cy.graphtyGenerate("complete", { n: 5 });

const boundingBox = { x1: 0, y1: 0, w: 600, h: 400 };
try {
    cy.layout({ name: "graphty-planar", boundingBox }).run();
} catch (err) {
    // The complete graph on 5 nodes is not planar: "G is not planar."
    console.log(err.message);
    cy.layout({ name: "graphty-kamada-kawai", boundingBox }).run();
}

Graphs a layout refuses

• graphty-planar throws G is not planar. for K5, K3,3 and a connected graph with more than 3n - 6 distinct edges. Other non-planar graphs are drawn with crossing edges.
• graphty-bfs throws on a disconnected graph, because the walk from root misses some nodes.
• graphty-spring-electrical runs only on the GPU. With no GPU, the layout emits layouterror and then layoutstop, and no node moves. Layouts shows how to handle it.

Memory on large graphs

graphty-kamada-kawai keeps one distance for every pair of nodes, so memory grows with the square of the node count: 10,000 nodes need about 800 MB. Use a force layout such as graphty-forceatlas2 above a few thousand nodes.

graphtyAllPairsShortestPath stores 12 bytes per pair with the default paths: true (8 for the distance, 4 for the predecessor), 8 with paths: false. It throws a RangeError on a graph of more than 5,792 nodes unless you pass a larger maxNodes. At 6,000 nodes the result is about 432 MB.

Positions are 2D

Every layout writes x and y only. With dim: 3, graphty-circular, graphty-random, graphty-kamada-kawai, graphty-arf and the three simulations place the nodes in three dimensions and z is dropped, so the drawing is the 3D result seen from above. The other layouts ignore dim.

Compound parents

A layout positions the leaf nodes only. Cytoscape places and sizes each compound parent from its children.

Loading a graph whose node ids are taken

cy.graphtyGenerate(), cy.graphtyDataset() and cy.graphtyImport() add nothing and reject when the core already holds one of the new graph's node ids. Call cy.elements().remove() first. See Direction and existing elements.

Layout weight is typed as a field name only

A layout's weight option takes an edge data field name, such as weight: "w", or a function of the edge, such as weight: (edge) => edge.data("w"). Both work at run time. The TypeScript type accepts only the field name, so in TypeScript a function fails to type-check. Algorithm options are typed for both.

GPU results are single precision

A result computed on the GPU can differ from the CPU result in the last digits. Label propagation can break ties differently. The WebGPU page lists the tolerances.

The script-tag build loads most of the package at start

dist/cytoscape-extensions.bundle.js is about 249 KB gzipped, against about 114 KB at start for the ES module build. See Installation.