From edf6077eb469df10725bfb632ed8153a40ae62b0 Mon Sep 17 00:00:00 2001
From: Shivam Mishra <scm.mymail@gmail.com>
Date: Fri, 27 Sep 2019 14:49:30 +0530
Subject: [PATCH] feat: kick start funnel Chart

---
 src/js/charts/FunnelChart.js | 91 ++++++++++++++++++++++++++++++++++++
 src/js/utils/draw.js         | 26 +++++++++++
 2 files changed, 117 insertions(+)
 create mode 100644 src/js/charts/FunnelChart.js

diff --git a/src/js/charts/FunnelChart.js b/src/js/charts/FunnelChart.js
new file mode 100644
index 0000000..509b258
--- /dev/null
+++ b/src/js/charts/FunnelChart.js
@@ -0,0 +1,91 @@
+import AggregationChart from './AggregationChart';
+import { getOffset } from '../utils/dom';
+import { getComponent } from '../objects/ChartComponents';
+import { PERCENTAGE_BAR_DEFAULT_HEIGHT, PERCENTAGE_BAR_DEFAULT_DEPTH } from '../utils/constants';
+
+export default class FunnelChart extends AggregationChart {
+	constructor(parent, args) {
+		super(parent, args);
+		this.type = 'funnel';
+		this.setup();
+	}
+
+	setMeasures(options) {
+		let m = this.measures;
+		this.funnelOptions = options.funnelOptions || {};
+
+		let opts = this.funnelOptions;
+		opts.height = opts.height || PERCENTAGE_BAR_DEFAULT_HEIGHT;
+
+		m.paddings.right = 30;
+		m.legendHeight = 60;
+		m.baseHeight = (opts.height + opts.depth * 0.5) * 8;
+	}
+
+	setupComponents() {
+		let s = this.state;
+
+		let componentConfigs = [
+			[
+				'percentageBars',
+				{
+					barHeight: this.funnelOptions.height,
+					barDepth: this.funnelOptions.depth,
+				},
+				function() {
+					return {
+						xPositions: s.xPositions,
+						widths: s.widths,
+						colors: this.colors
+					};
+				}.bind(this)
+			]
+		];
+
+		this.components = new Map(componentConfigs
+			.map(args => {
+				let component = getComponent(...args);
+				return [args[0], component];
+			}));
+	}
+
+	calc() {
+		super.calc();
+		let s = this.state;
+
+		s.xPositions = [];
+		s.widths = [];
+
+		let xPos = 0;
+		s.sliceTotals.map((value) => {
+			let width = this.width * value / s.grandTotal;
+			s.widths.push(width);
+			s.xPositions.push(xPos);
+			xPos += width;
+		});
+	}
+
+	makeDataByIndex() { }
+
+	bindTooltip() {
+		let s = this.state;
+		this.container.addEventListener('mousemove', (e) => {
+			let bars = this.components.get('percentageBars').store;
+			let bar = e.target;
+			if(bars.includes(bar)) {
+
+				let i = bars.indexOf(bar);
+				let gOff = getOffset(this.container), pOff = getOffset(bar);
+
+				let x = pOff.left - gOff.left + parseInt(bar.getAttribute('width'))/2;
+				let y = pOff.top - gOff.top;
+				let title = (this.formattedLabels && this.formattedLabels.length>0
+					? this.formattedLabels[i] : this.state.labels[i]) + ': ';
+				let fraction = s.sliceTotals[i]/s.grandTotal;
+
+				this.tip.setValues(x, y, {name: title, value: (fraction*100).toFixed(1) + "%"});
+				this.tip.showTip();
+			}
+		});
+	}
+}
diff --git a/src/js/utils/draw.js b/src/js/utils/draw.js
index d7e26cd..173951e 100644
--- a/src/js/utils/draw.js
+++ b/src/js/utils/draw.js
@@ -190,6 +190,32 @@ export function percentageBar(x, y, width, height,
 	return createSVG("rect", args);
 }
 
+export function funnelSlice(className, startPositions, height, fill='none') {
+	const endPosition = []
+	let [point_a, point_b] = startPositions[0]
+
+	// For an equilateral triangle, the angles are always 60 deg.
+	// The end points on the polygons can be created using the following formula
+	//
+	// end_point_x = start_x + height
+	// end_point_y = start_y +/- height * 1/2
+	//
+	//      b
+	//    _______________________________
+	//    \  |_|                        /
+	//     \   |                       /
+	//      \  | h                    /
+	//       \ |                     /
+	//        \|____________________/
+	//
+	//     b = h * cos(60 deg)
+	//
+
+	endPosition[0] = [point_a[0] + height, point_a[1] + height * 0.5]
+	endPosition[1] = [point_b[0] + height, point_b[1] - height * 0.5]
+
+}
+
 export function heatSquare(className, x, y, size, fill='none', data={}) {
 	let args = {
 		className: className,