Plugin Track Development

Plugin tracks are tracks which have an external code base but otherwise work just like normal track. We strongly recommend to develop new types of tracks as plugin tracks and only add very generic track so the HiGlass core library.

Basic skeleton

A plugin track consist of two nested classes defining a wrapper, which loads HiGlass specific libraries and the actual track class that is similar to any other track. In the follow you can see a bare minimum example of this structure.

import { registerTrack } from 'higlass-register';

const MyPluginTrack = function MyPluginTrack(HGC, ...args) {
  if (!new.target) {
    throw new Error(
      'Uncaught TypeError: Class constructor cannot be invoked without "new"'
    );
  }

  // A tracks you want to extend with your plugin track. You should at the
  // very least extend PixiTrack.
  const { BarTrack } = HGC.tracks;

  // Other libraries, utils, etc. that are provided by HiGlass (HGC)
  const { ... } = HGC.libraries;
  const { ... } = HGC.utils;
  const { ... } = HGC.factories;
  const { ... } = HGC.services;
  const { ... } = HGC.utils;
  const { ... } = HGC.configs;

  // The version of HiGlass. Can be used to check for compatibility.
  const hgVersion = HGC.VERSION;

  class RangeTrackClass extends HGC.tracks.BarTrack {
    constructor(context, options) {
      super(context, options);

      ...
    }
  }
}

const icon = '<svg ...>...</svg>';

MyPluginTrack.config = {
  type: 'my-track',
  orientation: '1d-horizontal',
  thumbnail: new DOMParser().parseFromString(icon, 'text/xml').documentElement,
  availableOptions: [ myNewOption ],
  defaultOptions: {
    myNewOption: 'default-value'
  },
  optionsInfo: {
    myNewOption: {
      name: "My track specific option",
      value: "option-value"
    }
  }
};

// It's important that you register your plugin track
// with HiGlass otherwise HiGlass will not know about it
registerTrack({
  name: 'MyPluginTrack',
  track: MyPluginTrack,
  config: MyPluginTrack.config
});

export default MyPluginTrack;

The best way to get start implementing a plugin tracks is to take a look at existing plugin tracks and their code. You can find a list of all officially supported plugin tracks can be found at higlass.io/plugins

In order to make the track display anything interesting you need to extend the existing rendering methods. To find out how HiGlass renders data please take a look at some core tracks like BarTrack.js.

Available tracks, libraries, and utils

Plugin tracks have access to many core tracks, libraries, and internal utilities.

Please visit the “available to plugins” page for an overview of all available imports that plugin tracks and data fetchers may access.