text: /**
   * Copyright (c) 2017 ~ present NAVER Corp.
   * billboard.js project is licensed under the MIT license
   */
  /**
   * Stanford diagram plugin option class
   * @class StanfordOptions
   * @param {Options} options Stanford plugin options
   * @extends Plugin
   * @return {StanfordOptions}
   * @private
   */
  export default class Options {
  	constructor() {
  		return {
  
  			/**
  			 * Set the color of the color scale. This function receives a value between 0 and 1, and should return a color.
  			 * @name colors
  			 * @memberof plugin-stanford
  			 * @type {Function}
  			 * @default undefined
  			 * @example
  			 *   colors: d3.interpolateHslLong(
  			 *      d3.hsl(250, 1, 0.5), d3.hsl(0, 1, 0.5)
  			 *   )
  			 */
  			colors: undefined,
  
  			/**
  			 * Specify the key of epochs values in the data.
  			 * @name epochs
  			 * @memberof plugin-stanford
  			 * @type {Array}
  			 * @default []
  			 * @example
  			 * 	epochs: [ 1, 1, 2, 2, ... ]
  			*/
  			epochs: [],
  
  			/**
  			 * Show additional lines anywhere on the chart.
  			 * - Each line object should consist with following options:
  			 *
  		 	 * | Key | Type | Description |
  			 * | --- | --- | --- |
  			 * | x1 | Number | Starting position on the x axis |
  			 * | y1 | Number | Starting position on the y axis |
  			 * | x2 | Number | Ending position on the x axis  |
  			 * | y2 | Number | Ending position on the y axis |
  			 * | class | String | Optional value. Set a custom css class to this line. |
  			 * @type {Array}
  			 * @memberof plugin-stanford
  			 * @default []
  			 * @example
  			 *   lines: [
  			 *       { x1: 0, y1: 0, x2: 65, y2: 65, class: "line1" },
  			 *       { x1: 0, x2: 65, y1: 40, y2: 40, class: "line2" }
  			 *   ]
  			 */
  			lines: [],
  
  			/**
  			 * Set scale values
  			 * @name scale
  			 * @memberof plugin-stanford
  			 * @type {Object}
   			 * @property {Number} [scale.min=undefined] Minimum value of the color scale. Default: lowest value in epochs
  			 * @property {Number} [scale.max=undefined] Maximum value of the color scale. Default: highest value in epochs
  			 * @property {Number} [scale.width=20] Width of the color scale
  			 * @property {String|Function} [scale.format=undefined] Format of the axis of the color scale. Use 'pow10' to format as powers of 10 or a custom function. Example: d3.format("d")
  			 * @example
  			 *  scale: {
  			 *    max: 10000,
  			 *    min: 1,
  			 *    width: 500,
  			 *    format: "pow10"
  			 *  },
  			 */
  			scale_min: undefined,
  			scale_max: undefined,
  			scale_width: 20,
  			scale_format: undefined,
  
  			/**
  			 * The padding for color scale element
  			 * @name padding
  			 * @memberof plugin-stanford
  			 * @type {Object}
  			 * @property {Number} [padding.top=0] Top padding value.
  			 * @property {Number} [padding.right=0] Right padding value.
  			 * @property {Number} [padding.bottom=0] Bottom padding value.
  			 * @property {Number} [padding.left=0] Left padding value.
  			 * @example
  			 *  padding: {
  			 *     top: 15,
  			 *     right: 0,
  			 *     bottom: 0,
  			 *     left: 0
  			 *  },
  			 */
  			padding_top: 0,
  			padding_right: 0,
  			padding_bottom: 0,
  			padding_left: 0,
  
  			/**
  			 * Show additional regions anywhere on the chart.
  			 * - Each region object should consist with following options:
  			 *
  			 * | Key | Type | Default | Description |
  			 * | --- | --- | --- | --- |
  			 * | points | Array |  | Accepts a group of objects that has x and y.<br>These points should be added in a counter-clockwise fashion to make a closed polygon. |
  			 * | opacity | Number | 0.2 | Optional value. Sets the opacity of the region as value between 0 and 1 |
  			 * | text | Function |  | Optional value. This function receives a value and percentage of the number of epochs in this region.<br>Return a string to place text in the middle of the region. |
  			 * | class | String | | Optional value. Set a custom css class to this region, use the fill property in css to set a background color. |
  			 * @name regions
  			 * @memberof plugin-stanford
  			 * @type {Array}
  			 * @default []
  			 * @example
  			 *   regions: [
  			 *       {
  			 *           points: [ // add points counter-clockwise
  			 *               { x: 0, y: 0 },
  			 *               { x: 40, y: 40 },
  			 *               { x: 0, y: 40 },
  			 *           ],
  			 *           text: function (value, percentage) {
  			 *               return `Normal Operations: ${value} (${percentage}%)`;
  			 *           },
  			 *           opacity: 0.2, // 0 to 1
  			 *           class: "test-polygon1"
  		 	 *       },
  			 *       ...
  			 *   ]
  			 */
  			regions: []
  		};
  	}
  }
  