chart/ganttChart.js

import * as d3 from "d3";
import palette from "../palette";
import dataTransform from "../dataTransform";
import component from "../component";

/**
 * Gantt Chart
 *
 * @module
 * @see http://datavizproject.com/data-type/gannt-chart/
 */
export default function() {

	/* Default Properties */
	let svg;
	let chart;
	let classed = "ganttChart";
	let width = 600;
	let height = 400;
	let margin = { top: 20, right: 20, bottom: 40, left: 80 };
	let transition = { ease: d3.easeBounce, duration: 500 };
	let colors = d3.ez.palette.categorical(3);
	let dispatch = d3.dispatch("customValueMouseOver", "customValueMouseOut", "customValueClick", "customSeriesMouseOver", "customSeriesMouseOut", "customSeriesClick");

	/* Chart Dimensions */
	let chartW;
	let chartH;

	/* Scales */
	let xScale;
	let yScale;
	let colorScale;

	/* Other Customisation Options */
	let tickFormat = "%d-%b-%y";
	let dateDomainMin;
	let dateDomainMax;

	/**
	 * Initialise Data and Scales
	 *
	 * @private
	 * @param {Array} data - Chart data.
	 */
	let init = function(data) {
		chartW = width - (margin.left + margin.right);
		chartH = height - (margin.top + margin.bottom);

		let { rowKeys, columnKeys } = dataTransform(data).summary();


		// TODO: Use dataTransform() to calculate date domains?
		data.forEach(function(d) {
			d.values.forEach(function(b) {
				dateDomainMin = d3.min([b.startDate, dateDomainMin]);
				dateDomainMax = d3.max([b.endDate, dateDomainMax]);
			});
		});
		const dateDomain = [dateDomainMin, dateDomainMax];


		if (typeof colorScale === "undefined") {
			colorScale = d3.scaleOrdinal()
				.domain(columnKeys)
				.range(colors);
		}

		xScale = d3.scaleTime()
			.domain(dateDomain)
			.range([0, chartW])
			.clamp(true);

		yScale = d3.scaleBand()
			.domain(rowKeys)
			.rangeRound([0, chartH])
			.padding(0.1);
	};

	/**
	 * Constructor
	 *
	 * @constructor
	 * @alias ganttChart
	 * @param {d3.selection} selection - The chart holder D3 selection.
	 */
	let my = function(selection) {
		// Create SVG element (if it does not exist already)
		if (!svg) {
			svg = (function(selection) {
				const el = selection._groups[0][0];
				if (!!el.ownerSVGElement || el.tagName === "svg") {
					return selection;
				} else {
					return selection.append("svg");
				}
			})(selection);

			svg.classed("d3ez", true)
				.attr("width", width)
				.attr("height", height);

			chart = svg.append("g").classed("chart", true);
		} else {
			chart = selection.select(".chart");
		}

		// Update the chart dimensions and add layer groups
		const layers = ["ganttBarGroup", "xAxis axis", "yAxis axis"];
		chart.classed(classed, true)
			.attr("transform", "translate(" + margin.left + "," + margin.top + ")")
			.attr("width", chartW)
			.attr("height", chartH)
			.selectAll("g")
			.data(layers)
			.enter()
			.append("g")
			.attr("class", (d) => d);

		selection.each(function(data) {
			// Initialise Data
			init(data);

			// Create bar groups
			const seriesGroup = chart.select(".ganttBarGroup")
				.selectAll(".seriesGroup")
				.data(data)
				.enter()
				.append("g")
				.classed("seriesGroup", true)
				.attr("id", (d) => d.key)
				.attr("transform", (d) => "translate(0," + yScale(d.key) + ")");

			// Add bars
			const bars = seriesGroup.selectAll(".bar")
				.data((d) => d.values);

			bars.enter()
				.append("rect")
				.attr("rx", 3)
				.attr("ry", 3)
				.attr("class", "bar")
				.attr("y", 0)
				.attr("x", (d) => xScale(d.startDate))
				.attr("height", yScale.bandwidth())
				.attr("fill", (d) => colorScale(d.key))
				.attr("width", (d) => Math.max(1, (xScale(d.endDate) - xScale(d.startDate))))
				.on("mouseover", (d) => dispatch.call("customValueMouseOver", this, d))
				.on("click", (d) => dispatch.call("customValueClick", this, d))
				.merge(bars)
				.transition()
				.ease(transition.ease)
				.duration(transition.duration)
				.attr("x", (d) => xScale(d.startDate))
				.attr("width", (d) => Math.max(1, (xScale(d.endDate) - xScale(d.startDate))));

			const xAxis = d3.axisBottom()
				.scale(xScale)
				.tickFormat(d3.timeFormat(tickFormat))
				.tickSize(8)
				.tickPadding(8);

			chart.select(".xAxis")
				.attr("transform", "translate(0, " + chartH + ")")
				.call(xAxis);

			const yAxis = d3.axisLeft()
				.scale(yScale)
				.tickSize(0);

			chart.select(".yAxis")
				.call(yAxis);
		});
	};

	/**
	 * Width Getter / Setter
	 *
	 * @param {number} _v - Width in px.
	 * @returns {*}
	 */
	my.width = function(_v) {
		if (!arguments.length) return width;
		width = _v;
		return this;
	};

	/**
	 * Height Getter / Setter
	 *
	 * @param {number} _v - Height in px.
	 * @returns {*}
	 */
	my.height = function(_v) {
		if (!arguments.length) return height;
		height = _v;
		return this;
	};

	/**
	 * Margin Getter / Setter
	 *
	 * @param {number} _v - Margin in px.
	 * @returns {*}
	 */
	my.margin = function(_v) {
		if (!arguments.length) return margin;
		margin = _v;
		return this;
	};

	/**
	 * Colors Getter / Setter
	 *
	 * @param {Array} _v - Array of colours used by color scale.
	 * @returns {*}
	 */
	my.colors = function(_v) {
		if (!arguments.length) return colors;
		colors = _v;
		return this;
	};

	/**
	 * Color Scale Getter / Setter
	 *
	 * @param {d3.scale} _v - D3 color scale.
	 * @returns {*}
	 */
	my.colorScale = function(_v) {
		if (!arguments.length) return colorScale;
		colorScale = _v;
		return this;
	};

	/**
	 * Time Domain Getter / Setter
	 *
	 * @param {array} _v - Time domain array.
	 * @returns {*}
	 */
	my.timeDomain = function(_v) {
		if (!arguments.length) return [dateDomainMin, dateDomainMax];
		dateDomainMin = _[0];
		dateDomainMax = _[1];
		return this;
	};

	/**
	 * Tick Format Getter / Setter
	 *
	 * @param {string} _v - String format.
	 * @returns {*}
	 */
	my.tickFormat = function(_v) {
		if (!arguments.length) return tickFormat;
		tickFormat = _v;
		return this;
	};

	/**
	 * Transition Getter / Setter
	 *
	 * @param {d3.transition} _v - D3 transition style.
	 * @returns {*}
	 */
	my.transition = function(_v) {
		if (!arguments.length) return transition;
		transition = _v;
		return this;
	};

	/**
	 * Dispatch Getter / Setter
	 *
	 * @param {d3.dispatch} _v - Dispatch event handler.
	 * @returns {*}
	 */
	my.dispatch = function(_v) {
		if (!arguments.length) return dispatch();
		dispatch = _v;
		return this;
	};

	/**
	 * Dispatch On Getter
	 *
	 * @returns {*}
	 */
	my.on = function() {
		let value = dispatch.on.apply(dispatch, arguments);
		return value === dispatch ? my : value;
	};

	return my;
}