philogb / mingle

A JS implementation of the MINGLE edge bundling algorithm

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Multilevel Agglomerative Edge Bundling in JavaScript

This is a JavaScript implementation of the paper Multilevel Agglomerative Edge Bundling for Visualizing Large Graphs (Emden R. Gansner, Yifan Hu, Stephen North, Carlos Scheidegger).

The edge bundling algorithm groups edges together to minimize the amount of ink used to render a graph. This particular paper introduces a fast technique to perform edge bundling.

Take for example this map connecting locations between the east coast in the US and western Europe:

The algorithm creates a proximity graph for the edges where each of the edges is represented by a node. Then the algorithm bundles edges as long as we're saving some ink in the final rendering. Here's an intermediate step on the bundling animation:

And here's the final result:

This implementation is solely based on the paper. The license for the code is MIT.

Examples

This simple example shows links connecting locations in the Bay Area. The rendering uses 2D Canvas but could use any other rendering API.

Usage

Given a dataset consisting of an Array of elements with format:

``````  {
"id": <string id>,
"name": <string name>,
"data": {
"coords": [
<coord x from>,
<coord y from>,
<coord x to>,
<coord y to>
]
}
}
``````

Then the code to create the bundled edges graph is:

``````  var bundle = new Bundler();
bundle.setNodes(json);
bundle.buildNearestNeighborGraph();
bundle.MINGLE();
``````

Finally, to render the graph we provide some helper functions that make use of 2D canvas:

``````  bundle.graph.each(function(node) {
ctx.strokeStyle = 'rgba(0, 200, 200, 0.2)';
ctx.lineWidth = 2;
var edges = node.unbundleEdges(delta);
Bundler.Graph.renderBezier(ctx, edges);
});
``````

External libraries used

• kdtree implementation by Ubilabs can be found here. MIT license.
• PhiloGL is used to perform animations between unbundled and bundled edges. This library is not required to use the algorithm. MIT license.

TODO

Provide a more complete documentation and API reference.

``````    Copyright (c) 2013 Twitter - Author: Nicolas Garcia Belmonte
(http://philogb.github.io/)

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
``````

A JS implementation of the MINGLE edge bundling algorithm