Refactor to be simpler

Author: nagix

src/controllers/controller.doughnut.js

@@ -8,6 +8,10 @@ var helpers = require('../helpers/index');
 var resolve = helpers.options.resolve;
 var valueOrDefault = helpers.valueOrDefault;
 
+var PI = Math.PI;
+var DOUBLE_PI = PI * 2;
+var HALF_PI = PI / 2;
+
 defaults._set('doughnut', {
 	animation: {
 		// Boolean - Whether we animate the rotation of the Doughnut
@@ -91,10 +95,10 @@ defaults._set('doughnut', {
 	cutoutPercentage: 50,
 
 	// The rotation of the chart, where the first data arc begins.
-	rotation: Math.PI * -0.5,
+	rotation: -HALF_PI,
 
 	// The total circumference of the chart.
-	circumference: Math.PI * 2.0,
+	circumference: DOUBLE_PI,
 
 	// Need to override these to give a nice default
 	tooltips: {
@@ -145,45 +149,52 @@ module.exports = DatasetController.extend({
 		var chart = me.chart;
 		var chartArea = chart.chartArea;
 		var opts = chart.options;
-		var size = {width: 1, height: 1};
-		var offset = {x: 0, y: 0};
+		var ratioX = 1;
+		var ratioY = 1;
+		var offsetX = 0;
+		var offsetY = 0;
 		var meta = me.getMeta();
 		var arcs = meta.data;
-		var cutoutPercentage = opts.cutoutPercentage;
+		var cutout = opts.cutoutPercentage / 100 || 0;
 		var circumference = opts.circumference;
 		var chartWeight = me._getRingWeight(me.index);
 		var maxWidth, maxHeight, i, ilen;
 
 		// If the chart's circumference isn't a full circle, calculate size as a ratio of the width/height of the arc
-		if (circumference < Math.PI * 2.0) {
-			var startAngle = opts.rotation % (Math.PI * 2.0);
-			startAngle += Math.PI * 2.0 * (startAngle >= Math.PI ? -1 : startAngle < -Math.PI ? 1 : 0);
+		if (circumference < DOUBLE_PI) {
+			var startAngle = opts.rotation % DOUBLE_PI;
+			startAngle += startAngle >= PI ? -DOUBLE_PI : startAngle < -PI ? DOUBLE_PI : 0;
 			var endAngle = startAngle + circumference;
-			var start = {x: Math.cos(startAngle), y: Math.sin(startAngle)};
-			var end = {x: Math.cos(endAngle), y: Math.sin(endAngle)};
-			var contains0 = (startAngle <= 0 && endAngle >= 0) || (startAngle <= Math.PI * 2.0 && Math.PI * 2.0 <= endAngle);
-			var contains90 = (startAngle <= Math.PI * 0.5 && Math.PI * 0.5 <= endAngle) || (startAngle <= Math.PI * 2.5 && Math.PI * 2.5 <= endAngle);
-			var contains180 = (startAngle <= -Math.PI && -Math.PI <= endAngle) || (startAngle <= Math.PI && Math.PI <= endAngle);
-			var contains270 = (startAngle <= -Math.PI * 0.5 && -Math.PI * 0.5 <= endAngle) || (startAngle <= Math.PI * 1.5 && Math.PI * 1.5 <= endAngle);
-			var cutout = cutoutPercentage / 100.0;
-			var min = {x: contains180 ? -1 : Math.min(start.x * (start.x < 0 ? 1 : cutout), end.x * (end.x < 0 ? 1 : cutout)), y: contains270 ? -1 : Math.min(start.y * (start.y < 0 ? 1 : cutout), end.y * (end.y < 0 ? 1 : cutout))};
-			var max = {x: contains0 ? 1 : Math.max(start.x * (start.x > 0 ? 1 : cutout), end.x * (end.x > 0 ? 1 : cutout)), y: contains90 ? 1 : Math.max(start.y * (start.y > 0 ? 1 : cutout), end.y * (end.y > 0 ? 1 : cutout))};
-			size = {width: (max.x - min.x) * 0.5, height: (max.y - min.y) * 0.5};
-			offset = {x: (max.x + min.x) * -0.5, y: (max.y + min.y) * -0.5};
+			var startX = Math.cos(startAngle);
+			var startY = Math.sin(startAngle);
+			var endX = Math.cos(endAngle);
+			var endY = Math.sin(endAngle);
+			var contains0 = (startAngle <= 0 && endAngle >= 0) || endAngle >= DOUBLE_PI;
+			var contains90 = (startAngle <= HALF_PI && endAngle >= HALF_PI) || endAngle >= DOUBLE_PI + HALF_PI;
+			var contains180 = startAngle === -PI || endAngle >= PI;
+			var contains270 = (startAngle <= -HALF_PI && endAngle >= -HALF_PI) || endAngle >= PI + HALF_PI;
+			var minX = contains180 ? -1 : Math.min(startX, startX * cutout, endX, endX * cutout);
+			var minY = contains270 ? -1 : Math.min(startY, startY * cutout, endY, endY * cutout);
+			var maxX = contains0 ? 1 : Math.max(startX, startX * cutout, endX, endX * cutout);
+			var maxY = contains90 ? 1 : Math.max(startY, startY * cutout, endY, endY * cutout);
+			ratioX = (maxX - minX) / 2;
+			ratioY = (maxY - minY) / 2;
+			offsetX = -(maxX + minX) / 2;
+			offsetY = -(maxY + minY) / 2;
 		}
 
 		for (i = 0, ilen = arcs.length; i < ilen; ++i) {
 			arcs[i]._options = me._resolveElementOptions(arcs[i], i);
 		}
 
 		chart.borderWidth = me.getMaxBorderWidth();
-		maxWidth = (chartArea.right - chartArea.left - chart.borderWidth) / size.width;
-		maxHeight = (chartArea.bottom - chartArea.top - chart.borderWidth) / size.height;
+		maxWidth = (chartArea.right - chartArea.left - chart.borderWidth) / ratioX;
+		maxHeight = (chartArea.bottom - chartArea.top - chart.borderWidth) / ratioY;
 		chart.outerRadius = Math.max(Math.min(maxWidth, maxHeight) / 2, 0);
-		chart.innerRadius = Math.max(cutoutPercentage ? (chart.outerRadius / 100) * (cutoutPercentage) : 0, 0);
+		chart.innerRadius = Math.max(chart.outerRadius * cutout, 0);
 		chart.radiusLength = (chart.outerRadius - chart.innerRadius) / (me._getVisibleDatasetWeightTotal() || 1);
-		chart.offsetX = offset.x * chart.outerRadius;
-		chart.offsetY = offset.y * chart.outerRadius;
+		chart.offsetX = offsetX * chart.outerRadius;
+		chart.offsetY = offsetY * chart.outerRadius;
 
 		meta.total = me.calculateTotal();
 
@@ -206,7 +217,7 @@ module.exports = DatasetController.extend({
 		var startAngle = opts.rotation; // non reset case handled later
 		var endAngle = opts.rotation; // non reset case handled later
 		var dataset = me.getDataset();
-		var circumference = reset && animationOpts.animateRotate ? 0 : arc.hidden ? 0 : me.calculateCircumference(dataset.data[index]) * (opts.circumference / (2.0 * Math.PI));
+		var circumference = reset && animationOpts.animateRotate ? 0 : arc.hidden ? 0 : me.calculateCircumference(dataset.data[index]) * (opts.circumference / DOUBLE_PI);
 		var innerRadius = reset && animationOpts.animateScale ? 0 : me.innerRadius;
 		var outerRadius = reset && animationOpts.animateScale ? 0 : me.outerRadius;
 		var options = arc._options || {};
@@ -272,7 +283,7 @@ module.exports = DatasetController.extend({
 	calculateCircumference: function(value) {
 		var total = this.getMeta().total;
 		if (total > 0 && !isNaN(value)) {
-			return (Math.PI * 2.0) * (Math.abs(value) / total);
+			return DOUBLE_PI * (Math.abs(value) / total);
 		}
 		return 0;
 	},