A force directed graph layout algorithm in JavaScript.

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What is Springy?

Springy is a force directed graph layout algorithm.

So what does this “force directed” stuff mean anyway? Excellent question!

It means that springy uses some real world physics to try and figure out how to show a network graph in a way that looks good.

Here's an example:

Sequoya gigantea

Getting started

Springy.js is designed to be small and simple. It provides an abstraction for graph manipulation and for calculating the layout and not too much else.

The details of drawing and interaction are mostly up to you. This means you can use canvas, SVG, WebGL, or even just plain old positioned HTML elements.

Creating a graph

Here's how to create a graph and add nodes and edges:

// make a new graph
var graph = new Springy.Graph();

// make some nodes
var spruce = graph.newNode({label: 'Norway Spruce'});
var fir = graph.newNode({label: 'Sicilian Fir'});

// connect them with an edge
graph.newEdge(spruce, fir);

Once you've created a graph, there are a couple of options for displaying it.

Use the springyui.js renderer

To help get started quickly, I've included a helper jQuery plugin called springyui.js. It's got a semi‑decent default renderer and some half‑assed drag and drop.

Here's how to use springyui.js:

<canvas id="my_canvas" width="600" height="400" />
$('#my_canvas').springy({ graph: graph });

Do your own rendering

If you're keen to do your own custom drawing or interaction—there's a few extra things you'll need to know.

The core Springy layout algorithm is in the Springy.Layout.ForceDirected class.

When creating a layout object, there are a few parameters you can tune to make the graph layout algorithm behave how you like:

var layout = new Springy.Layout.ForceDirected(
  400.0, // Spring stiffness
  400.0, // Node repulsion
  0.5 // Damping

To simplify the layout calculation and animation rendering loop, I've provided a Renderer class. You just need to provide some callbacks to do the actual drawing:

var renderer = new Springy.Renderer(
  function clear() {
    // code to clear screen
  function drawEdge(edge, p1, p2) {
    // draw an edge
  function drawNode(node, p) {
    // draw a node

Then to start the rendering loop:


Protip: Take a look at the source code of springyui.js to get an idea of how to write your own renderer—it's a good place to start. Feel free to copy‑paste what you need.

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Further reading

Take a look at the source code of springy.js. Don't be shy—there's not that much code and it should be pretty easy to understand.

Please let me know if anything is unclear. Feedback is welcome. :-)

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Springy is licensed under the MIT license.


Contributions are welcome and highly encouraged. Please submit a pull request for fixes, features or enhancements.


Thanks to Lachlan Donald for his helpful suggestions and feedback.

Thanks to Ernst Haeckel for the beautiful illustrations of various Coniferae.

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