feat: generated funnel chart

src/js/charts/FunnelChart.js

@@ -1,25 +1,40 @@
 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';
+import { getEndpointsForTrapezoid } from '../utils/draw-utils'
+import { FUNNEL_CHART_BASE_WIDTH } from '../utils/constants';
 
 export default class FunnelChart extends AggregationChart {
 	constructor(parent, args) {
 		super(parent, args);
 		this.type = 'funnel';
+		window.funnel = this;
 		this.setup();
 	}
 
-	setMeasures(options) {
-		let m = this.measures;
-		this.funnelOptions = options.funnelOptions || {};
+	calc() {
+		super.calc();
+		let s = this.state;
+		// calculate width and height options
+		const baseWidth = FUNNEL_CHART_BASE_WIDTH;
+		const totalheight = (Math.sqrt(3) * baseWidth) / 2.0;
 
-		let opts = this.funnelOptions;
-		opts.height = opts.height || PERCENTAGE_BAR_DEFAULT_HEIGHT;
+		// calculate total weightage
+		// as height decreases, area decreases by the square of the reduction
+		// hence, compensating by squaring the index value
 
-		m.paddings.right = 30;
-		m.legendHeight = 60;
-		m.baseHeight = (opts.height + opts.depth * 0.5) * 8;
+		const reducer = (accumulator, currentValue, index) => accumulator + currentValue * (Math.pow(index+1, 2));
+		const weightage = s.sliceTotals.reduce(reducer, 0.0);
+
+		let slicePoints = [];
+		let startPoint = [[0, 0], [FUNNEL_CHART_BASE_WIDTH, 0]]
+		s.sliceTotals.forEach((d, i) => {
+			let height = totalheight * d * Math.pow(i+1, 2) / weightage;
+			let endPoint = getEndpointsForTrapezoid(startPoint, height);
+			slicePoints.push([startPoint, endPoint]);
+			startPoint = endPoint;
+		})
+		s.slicePoints = slicePoints;
 	}
 
 	setupComponents() {
@@ -27,15 +42,11 @@ export default class FunnelChart extends AggregationChart {
 
 		let componentConfigs = [
 			[
-				'percentageBars',
-				{
-					barHeight: this.funnelOptions.height,
-					barDepth: this.funnelOptions.depth,
-				},
+				'funnelSlices',
+				{ },
 				function() {
 					return {
-						xPositions: s.xPositions,
-						widths: s.widths,
+						slicePoints: s.slicePoints,
 						colors: this.colors
 					};
 				}.bind(this)
@@ -49,43 +60,27 @@ export default class FunnelChart extends AggregationChart {
 			}));
 	}
 
-	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 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 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;
+		// 		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();
-			}
-		});
+		// 		this.tip.setValues(x, y, {name: title, value: (fraction*100).toFixed(1) + "%"});
+		// 		this.tip.showTip();
+		// 	}
+		// });
 	}
 }

src/js/objects/ChartComponents.js

@@ -1,5 +1,5 @@
 import { makeSVGGroup } from '../utils/draw';
-import { makeText, makePath, xLine, yLine, yMarker, yRegion, datasetBar, datasetDot, percentageBar, getPaths, heatSquare } from '../utils/draw';
+import { makeText, makePath, xLine, yLine, yMarker, yRegion, datasetBar, datasetDot, percentageBar, getPaths, heatSquare, funnelSlice } from '../utils/draw';
 import { equilizeNoOfElements } from '../utils/draw-utils';
 import { translateHoriLine, translateVertLine, animateRegion, animateBar,
 	animateDot, animatePath, animatePathStr } from '../utils/animate';
@@ -114,14 +114,18 @@ let componentConfigs = {
 			if(newData) return [];
 		}
 	},
-	funnelSlice: {
-		layerClass: 'funnel-slice',
+	funnelSlices: {
+		layerClass: 'funnel-slices',
 		makeElements(data) {
-			return data
+			return data.slicePoints.map((p, i) => {
+				return funnelSlice('funnel-slice', p[0], p[1], data.colors[i]);
+			});
 		},
 
-		animateElements: {}
-	}
+		animateElements(newData) {
+			if(newData) return [];
+		}
+	},
 	yAxis: {
 		layerClass: 'y axis',
 		makeElements(data) {

src/js/utils/constants.js

@@ -76,6 +76,8 @@ export const DOT_OVERLAY_SIZE_INCR = 4;
 export const PERCENTAGE_BAR_DEFAULT_HEIGHT = 20;
 export const PERCENTAGE_BAR_DEFAULT_DEPTH = 2;
 
+export const FUNNEL_CHART_BASE_WIDTH = 200
+
 // Fixed 5-color theme,
 // More colors are difficult to parse visually
 export const HEATMAP_DISTRIBUTION_SIZE = 5;
@@ -99,7 +101,8 @@ export const DEFAULT_COLORS = {
 	pie: DEFAULT_CHART_COLORS,
 	percentage: DEFAULT_CHART_COLORS,
 	heatmap: HEATMAP_COLORS_GREEN,
-	donut: DEFAULT_CHART_COLORS
+	donut: DEFAULT_CHART_COLORS,
+	funnel: DEFAULT_CHART_COLORS,
 };
 
 // Universal constants

src/js/utils/draw-utils.js

@@ -25,14 +25,14 @@ export function equilizeNoOfElements(array1, array2,
 	return [array1, array2];
 }
 
-export function getEndpointsForTrapezoid(startPositions) {
-	const endPosition = []
-	let [point_a, point_b] = startPositions
+export function getEndpointsForTrapezoid(startPositions, height) {
+	const endPosition = [];
+	let [point_a, point_b] = startPositions;
 
 	// 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 * 1/2
+	// end_point_x = start_x +/- height * 1/√3
 	// end_point_y = start_y + height
 	//
 	//      b
@@ -43,13 +43,14 @@ export function getEndpointsForTrapezoid(startPositions) {
 	//       \ |                     /
 	//        \|____________________/
 	//
-	//     b = h * cos(60 deg)
+	//     b = h * tan(30 deg)
 	//
 
-	endPosition[0] = [point_a[0] + height * 0.5, point_a[1] + height]
-	endPosition[1] = [point_b[0] - height * 0.5, point_b[1] + height]
+	let multiplicationFactor = 1.0/Math.sqrt(3);
+	endPosition[0] = [point_a[0] + height * multiplicationFactor, point_a[1] + height];
+	endPosition[1] = [point_b[0] - height * multiplicationFactor, point_b[1] + height];
 
-	return endPosition
+	return endPosition;
 }
 
 export function truncateString(txt, len) {

src/js/utils/draw.js

@@ -190,8 +190,14 @@ export function percentageBar(x, y, width, height,
 	return createSVG("rect", args);
 }
 
-export function funnelSlice(className, startPositions, endPosition, height, fill='none') {
-	return createSVG("polygon")
+export function funnelSlice(className, start, end, fill='none') {
+	const points = `${start[0].join()} ${start[1].join()} ${end[1].join()} ${end[0].join()}`
+	let args = {
+		className: 'funnel-slice',
+		points: points,
+		fill: fill
+	}
+	return createSVG("polygon", args)
 }
 
 export function heatSquare(className, x, y, size, fill='none', data={}) {