Chart.js

/*!
 * Chart.js
 * http://chartjs.org/
 * Version: 1.0.2
 *
 * Copyright 2015 Nick Downie
 * Released under the MIT license
 * https://github.com/nnnick/Chart.js/blob/master/LICENSE.md
 */


(function(){

	"use strict";

	//Declare root variable - window in the browser, global on the server
	var root = this,
		previous = root.Chart;

	//Occupy the global variable of Chart, and create a simple base class
	var Chart = function(context){
		var chart = this;
		this.canvas = context.canvas;

		this.ctx = context;

		//Variables global to the chart
		var computeDimension = function(element,dimension)
		{
			if (element['offset'+dimension])
			{
				return element['offset'+dimension];
			}
			else
			{
				return document.defaultView.getComputedStyle(element).getPropertyValue(dimension);
			}
		}

		var width = this.width = computeDimension(context.canvas,'Width');
		var height = this.height = computeDimension(context.canvas,'Height');

		// Firefox requires this to work correctly
		context.canvas.width  = width;
		context.canvas.height = height;

		var width = this.width = context.canvas.width;
		var height = this.height = context.canvas.height;
		this.aspectRatio = this.width / this.height;
		//High pixel density displays - multiply the size of the canvas height/width by the device pixel ratio, then scale.
		helpers.retinaScale(this);

		return this;
	};
	//Globally expose the defaults to allow for user updating/changing
	Chart.defaults = {
		global: {
			// Boolean - Whether to animate the chart
			animation: true,

			// Number - Number of animation steps
			animationSteps: 60,

			// String - Animation easing effect
			animationEasing: "easeOutQuart",

			// Boolean - If we should show the scale at all
			showScale: true,

			// Boolean - If we want to override with a hard coded scale
			scaleOverride: false,

			// ** Required if scaleOverride is true **
			// Number - The number of steps in a hard coded scale
			scaleSteps: null,
			// Number - The value jump in the hard coded scale
			scaleStepWidth: null,
			// Number - The scale starting value
			scaleStartValue: null,

			// String - Colour of the scale line
			scaleLineColor: "rgba(0,0,0,.1)",

			// Number - Pixel width of the scale line
			scaleLineWidth: 1,

			// Boolean - Whether to show labels on the scale
			scaleShowLabels: true,

			// Interpolated JS string - can access value
			scaleLabel: "<%=value%>",

			// Boolean - Whether the scale should stick to integers, and not show any floats even if drawing space is there
			scaleIntegersOnly: true,

			// Boolean - Whether the scale should start at zero, or an order of magnitude down from the lowest value
			scaleBeginAtZero: false,

			// String - Scale label font declaration for the scale label
			scaleFontFamily: "'Helvetica Neue', 'Helvetica', 'Arial', sans-serif",

			// Number - Scale label font size in pixels
			scaleFontSize: 12,

			// String - Scale label font weight style
			scaleFontStyle: "normal",

			// String - Scale label font colour
			scaleFontColor: "#666",

			// Boolean - whether or not the chart should be responsive and resize when the browser does.
			responsive: false,

			// Boolean - whether to maintain the starting aspect ratio or not when responsive, if set to false, will take up entire container
			maintainAspectRatio: true,

			// Boolean - Determines whether to draw tooltips on the canvas or not - attaches events to touchmove & mousemove
			showTooltips: true,

			// Boolean - Determines whether to draw built-in tooltip or call custom tooltip function
			customTooltips: false,

			// Array - Array of string names to attach tooltip events
			tooltipEvents: ["mousemove", "touchstart", "touchmove", "mouseout"],

			// String - Tooltip background colour
			tooltipFillColor: "rgba(0,0,0,0.8)",

			// String - Tooltip label font declaration for the scale label
			tooltipFontFamily: "'Helvetica Neue', 'Helvetica', 'Arial', sans-serif",

			// Number - Tooltip label font size in pixels
			tooltipFontSize: 14,

			// String - Tooltip font weight style
			tooltipFontStyle: "normal",

			// String - Tooltip label font colour
			tooltipFontColor: "#fff",

			// String - Tooltip title font declaration for the scale label
			tooltipTitleFontFamily: "'Helvetica Neue', 'Helvetica', 'Arial', sans-serif",

			// Number - Tooltip title font size in pixels
			tooltipTitleFontSize: 14,

			// String - Tooltip title font weight style
			tooltipTitleFontStyle: "bold",

			// String - Tooltip title font colour
			tooltipTitleFontColor: "#fff",

			// Number - pixel width of padding around tooltip text
			tooltipYPadding: 6,

			// Number - pixel width of padding around tooltip text
			tooltipXPadding: 6,

			// Number - Size of the caret on the tooltip
			tooltipCaretSize: 8,

			// Number - Pixel radius of the tooltip border
			tooltipCornerRadius: 6,

			// Number - Pixel offset from point x to tooltip edge
			tooltipXOffset: 10,

			// String - Template string for single tooltips
			tooltipTemplate: "<%if (label){%><%=label%>: <%}%><%= value %>",

			// String - Template string for single tooltips
			multiTooltipTemplate: "<%= value %>",

			// String - Colour behind the legend colour block
			multiTooltipKeyBackground: '#fff',

			// Function - Will fire on animation progression.
			onAnimationProgress: function(){},

			// Function - Will fire on animation completion.
			onAnimationComplete: function(){}

		}
	};

	//Create a dictionary of chart types, to allow for extension of existing types
	Chart.types = {};

	//Global Chart helpers object for utility methods and classes
	var helpers = Chart.helpers = {};

		//-- Basic js utility methods
	var each = helpers.each = function(loopable,callback,self){
			var additionalArgs = Array.prototype.slice.call(arguments, 3);
			// Check to see if null or undefined firstly.
			if (loopable){
				if (loopable.length === +loopable.length){
					var i;
					for (i=0; i<loopable.length; i++){
						callback.apply(self,[loopable[i], i].concat(additionalArgs));
					}
				}
				else{
					for (var item in loopable){
						callback.apply(self,[loopable[item],item].concat(additionalArgs));
					}
				}
			}
		},
		clone = helpers.clone = function(obj){
			var objClone = {};
			each(obj,function(value,key){
				if (obj.hasOwnProperty(key)) objClone[key] = value;
			});
			return objClone;
		},
		extend = helpers.extend = function(base){
			each(Array.prototype.slice.call(arguments,1), function(extensionObject) {
				each(extensionObject,function(value,key){
					if (extensionObject.hasOwnProperty(key)) base[key] = value;
				});
			});
			return base;
		},
		merge = helpers.merge = function(base,master){
			//Merge properties in left object over to a shallow clone of object right.
			var args = Array.prototype.slice.call(arguments,0);
			args.unshift({});
			return extend.apply(null, args);
		},
		indexOf = helpers.indexOf = function(arrayToSearch, item){
			if (Array.prototype.indexOf) {
				return arrayToSearch.indexOf(item);
			}
			else{
				for (var i = 0; i < arrayToSearch.length; i++) {
					if (arrayToSearch[i] === item) return i;
				}
				return -1;
			}
		},
		where = helpers.where = function(collection, filterCallback){
			var filtered = [];

			helpers.each(collection, function(item){
				if (filterCallback(item)){
					filtered.push(item);
				}
			});

			return filtered;
		},
		findNextWhere = helpers.findNextWhere = function(arrayToSearch, filterCallback, startIndex){
			// Default to start of the array
			if (!startIndex){
				startIndex = -1;
			}
			for (var i = startIndex + 1; i < arrayToSearch.length; i++) {
				var currentItem = arrayToSearch[i];
				if (filterCallback(currentItem)){
					return currentItem;
				}
			}
		},
		findPreviousWhere = helpers.findPreviousWhere = function(arrayToSearch, filterCallback, startIndex){
			// Default to end of the array
			if (!startIndex){
				startIndex = arrayToSearch.length;
			}
			for (var i = startIndex - 1; i >= 0; i--) {
				var currentItem = arrayToSearch[i];
				if (filterCallback(currentItem)){
					return currentItem;
				}
			}
		},
		inherits = helpers.inherits = function(extensions){
			//Basic javascript inheritance based on the model created in Backbone.js
			var parent = this;
			var ChartElement = (extensions && extensions.hasOwnProperty("constructor")) ? extensions.constructor : function(){ return parent.apply(this, arguments); };

			var Surrogate = function(){ this.constructor = ChartElement;};
			Surrogate.prototype = parent.prototype;
			ChartElement.prototype = new Surrogate();

			ChartElement.extend = inherits;

			if (extensions) extend(ChartElement.prototype, extensions);

			ChartElement.__super__ = parent.prototype;

			return ChartElement;
		},
		noop = helpers.noop = function(){},
		uid = helpers.uid = (function(){
			var id=0;
			return function(){
				return "chart-" + id++;
			};
		})(),
		warn = helpers.warn = function(str){
			//Method for warning of errors
			if (window.console && typeof window.console.warn == "function") console.warn(str);
		},
		amd = helpers.amd = (typeof define == 'function' && define.amd),
		//-- Math methods
		isNumber = helpers.isNumber = function(n){
			return !isNaN(parseFloat(n)) && isFinite(n);
		},
		max = helpers.max = function(array){
			return Math.max.apply( Math, array );
		},
		min = helpers.min = function(array){
			return Math.min.apply( Math, array );
		},
		cap = helpers.cap = function(valueToCap,maxValue,minValue){
			if(isNumber(maxValue)) {
				if( valueToCap > maxValue ) {
					return maxValue;
				}
			}
			else if(isNumber(minValue)){
				if ( valueToCap < minValue ){
					return minValue;
				}
			}
			return valueToCap;
		},
		getDecimalPlaces = helpers.getDecimalPlaces = function(num){
			if (num%1!==0 && isNumber(num)){
				return num.toString().split(".")[1].length;
			}
			else {
				return 0;
			}
		},
		toRadians = helpers.radians = function(degrees){
			return degrees * (Math.PI/180);
		},
		// Gets the angle from vertical upright to the point about a centre.
		getAngleFromPoint = helpers.getAngleFromPoint = function(centrePoint, anglePoint){
			var distanceFromXCenter = anglePoint.x - centrePoint.x,
				distanceFromYCenter = anglePoint.y - centrePoint.y,
				radialDistanceFromCenter = Math.sqrt( distanceFromXCenter * distanceFromXCenter + distanceFromYCenter * distanceFromYCenter);


			var angle = Math.PI * 2 + Math.atan2(distanceFromYCenter, distanceFromXCenter);

			//If the segment is in the top left quadrant, we need to add another rotation to the angle
			if (distanceFromXCenter < 0 && distanceFromYCenter < 0){
				angle += Math.PI*2;
			}

			return {
				angle: angle,
				distance: radialDistanceFromCenter
			};
		},
		aliasPixel = helpers.aliasPixel = function(pixelWidth){
			return (pixelWidth % 2 === 0) ? 0 : 0.5;
		},
		splineCurve = helpers.splineCurve = function(FirstPoint,MiddlePoint,AfterPoint,t){
			//Props to Rob Spencer at scaled innovation for his post on splining between points
			//http://scaledinnovation.com/analytics/splines/aboutSplines.html
			var d01=Math.sqrt(Math.pow(MiddlePoint.x-FirstPoint.x,2)+Math.pow(MiddlePoint.y-FirstPoint.y,2)),
				d12=Math.sqrt(Math.pow(AfterPoint.x-MiddlePoint.x,2)+Math.pow(AfterPoint.y-MiddlePoint.y,2)),
				fa=t*d01/(d01+d12),// scaling factor for triangle Ta
				fb=t*d12/(d01+d12);
			return {
				inner : {
					x : MiddlePoint.x-fa*(AfterPoint.x-FirstPoint.x),
					y : MiddlePoint.y-fa*(AfterPoint.y-FirstPoint.y)
				},
				outer : {
					x: MiddlePoint.x+fb*(AfterPoint.x-FirstPoint.x),
					y : MiddlePoint.y+fb*(AfterPoint.y-FirstPoint.y)
				}
			};
		},
		calculateOrderOfMagnitude = helpers.calculateOrderOfMagnitude = function(val){
			return Math.floor(Math.log(val) / Math.LN10);
		},
		calculateScaleRange = helpers.calculateScaleRange = function(valuesArray, drawingSize, textSize, startFromZero, integersOnly){

			//Set a minimum step of two - a point at the top of the graph, and a point at the base
			var minSteps = 2,
				maxSteps = Math.floor(drawingSize/(textSize * 1.5)),
				skipFitting = (minSteps >= maxSteps);

			var maxValue = max(valuesArray),
				minValue = min(valuesArray);

			// We need some degree of seperation here to calculate the scales if all the values are the same
			// Adding/minusing 0.5 will give us a range of 1.
			if (maxValue === minValue){
				maxValue += 0.5;
				// So we don't end up with a graph with a negative start value if we've said always start from zero
				if (minValue >= 0.5 && !startFromZero){
					minValue -= 0.5;
				}
				else{
					// Make up a whole number above the values
					maxValue += 0.5;
				}
			}

			var	valueRange = Math.abs(maxValue - minValue),
				rangeOrderOfMagnitude = calculateOrderOfMagnitude(valueRange),
				graphMax = Math.ceil(maxValue / (1 * Math.pow(10, rangeOrderOfMagnitude))) * Math.pow(10, rangeOrderOfMagnitude),
				graphMin = (startFromZero) ? 0 : Math.floor(minValue / (1 * Math.pow(10, rangeOrderOfMagnitude))) * Math.pow(10, rangeOrderOfMagnitude),
				graphRange = graphMax - graphMin,
				stepValue = Math.pow(10, rangeOrderOfMagnitude),
				numberOfSteps = Math.round(graphRange / stepValue);

			//If we have more space on the graph we'll use it to give more definition to the data
			while((numberOfSteps > maxSteps || (numberOfSteps * 2) < maxSteps) && !skipFitting) {
				if(numberOfSteps > maxSteps){
					stepValue *=2;
					numberOfSteps = Math.round(graphRange/stepValue);
					// Don't ever deal with a decimal number of steps - cancel fitting and just use the minimum number of steps.
					if (numberOfSteps % 1 !== 0){
						skipFitting = true;
					}
				}
				//We can fit in double the amount of scale points on the scale
				else{
					//If user has declared ints only, and the step value isn't a decimal
					if (integersOnly && rangeOrderOfMagnitude >= 0){
						//If the user has said integers only, we need to check that making the scale more granular wouldn't make it a float
						if(stepValue/2 % 1 === 0){
							stepValue /=2;
							numberOfSteps = Math.round(graphRange/stepValue);
						}
						//If it would make it a float break out of the loop
						else{
							break;
						}
					}
					//If the scale doesn't have to be an int, make the scale more granular anyway.
					else{
						stepValue /=2;
						numberOfSteps = Math.round(graphRange/stepValue);
					}

				}
			}

			if (skipFitting){
				numberOfSteps = minSteps;
				stepValue = graphRange / numberOfSteps;
			}

			return {
				steps : numberOfSteps,
				stepValue : stepValue,
				min : graphMin,
				max	: graphMin + (numberOfSteps * stepValue)
			};

		},
		/* jshint ignore:start */
		// Blows up jshint errors based on the new Function constructor
		//Templating methods
		//Javascript micro templating by John Resig - source at http://ejohn.org/blog/javascript-micro-templating/
		template = helpers.template = function(templateString, valuesObject){

			// If templateString is function rather than string-template - call the function for valuesObject

			if(templateString instanceof Function){
			 	return templateString(valuesObject);
		 	}

			var cache = {};
			function tmpl(str, data){
				// Figure out if we're getting a template, or if we need to
				// load the template - and be sure to cache the result.
				var fn = !/\W/.test(str) ?
				cache[str] = cache[str] :

				// Generate a reusable function that will serve as a template
				// generator (and which will be cached).
				new Function("obj",
					"var p=[],print=function(){p.push.apply(p,arguments);};" +

					// Introduce the data as local variables using with(){}
					"with(obj){p.push('" +

					// Convert the template into pure JavaScript
					str
						.replace(/[\r\t\n]/g, " ")
						.split("<%").join("\t")
						.replace(/((^|%>)[^\t]*)'/g, "$1\r")
						.replace(/\t=(.*?)%>/g, "',$1,'")
						.split("\t").join("');")
						.split("%>").join("p.push('")
						.split("\r").join("\\'") +
					"');}return p.join('');"
				);

				// Provide some basic currying to the user
				return data ? fn( data ) : fn;
			}
			return tmpl(templateString,valuesObject);
		},
		/* jshint ignore:end */
		generateLabels = helpers.generateLabels = function(templateString,numberOfSteps,graphMin,stepValue){
			var labelsArray = new Array(numberOfSteps);
			if (labelTemplateString){
				each(labelsArray,function(val,index){
					labelsArray[index] = template(templateString,{value: (graphMin + (stepValue*(index+1)))});
				});
			}
			return labelsArray;
		},
		//--Animation methods
		//Easing functions adapted from Robert Penner's easing equations
		//http://www.robertpenner.com/easing/
		easingEffects = helpers.easingEffects = {
			linear: function (t) {
				return t;
			},
			easeInQuad: function (t) {
				return t * t;
			},
			easeOutQuad: function (t) {
				return -1 * t * (t - 2);
			},
			easeInOutQuad: function (t) {
				if ((t /= 1 / 2) < 1) return 1 / 2 * t * t;
				return -1 / 2 * ((--t) * (t - 2) - 1);
			},
			easeInCubic: function (t) {
				return t * t * t;
			},
			easeOutCubic: function (t) {
				return 1 * ((t = t / 1 - 1) * t * t + 1);
			},
			easeInOutCubic: function (t) {
				if ((t /= 1 / 2) < 1) return 1 / 2 * t * t * t;
				return 1 / 2 * ((t -= 2) * t * t + 2);
			},
			easeInQuart: function (t) {
				return t * t * t * t;
			},
			easeOutQuart: function (t) {
				return -1 * ((t = t / 1 - 1) * t * t * t - 1);
			},
			easeInOutQuart: function (t) {
				if ((t /= 1 / 2) < 1) return 1 / 2 * t * t * t * t;
				return -1 / 2 * ((t -= 2) * t * t * t - 2);
			},
			easeInQuint: function (t) {
				return 1 * (t /= 1) * t * t * t * t;
			},
			easeOutQuint: function (t) {
				return 1 * ((t = t / 1 - 1) * t * t * t * t + 1);
			},
			easeInOutQuint: function (t) {
				if ((t /= 1 / 2) < 1) return 1 / 2 * t * t * t * t * t;
				return 1 / 2 * ((t -= 2) * t * t * t * t + 2);
			},
			easeInSine: function (t) {
				return -1 * Math.cos(t / 1 * (Math.PI / 2)) + 1;
			},
			easeOutSine: function (t) {
				return 1 * Math.sin(t / 1 * (Math.PI / 2));
			},
			easeInOutSine: function (t) {
				return -1 / 2 * (Math.cos(Math.PI * t / 1) - 1);
			},
			easeInExpo: function (t) {
				return (t === 0) ? 1 : 1 * Math.pow(2, 10 * (t / 1 - 1));
			},
			easeOutExpo: function (t) {
				return (t === 1) ? 1 : 1 * (-Math.pow(2, -10 * t / 1) + 1);
			},
			easeInOutExpo: function (t) {
				if (t === 0) return 0;
				if (t === 1) return 1;
				if ((t /= 1 / 2) < 1) return 1 / 2 * Math.pow(2, 10 * (t - 1));
				return 1 / 2 * (-Math.pow(2, -10 * --t) + 2);
			},
			easeInCirc: function (t) {
				if (t >= 1) return t;
				return -1 * (Math.sqrt(1 - (t /= 1) * t) - 1);
			},
			easeOutCirc: function (t) {
				return 1 * Math.sqrt(1 - (t = t / 1 - 1) * t);
			},
			easeInOutCirc: function (t) {
				if ((t /= 1 / 2) < 1) return -1 / 2 * (Math.sqrt(1 - t * t) - 1);
				return 1 / 2 * (Math.sqrt(1 - (t -= 2) * t) + 1);
			},
			easeInElastic: function (t) {
				var s = 1.70158;
				var p = 0;
				var a = 1;
				if (t === 0) return 0;
				if ((t /= 1) == 1) return 1;
				if (!p) p = 1 * 0.3;
				if (a < Math.abs(1)) {
					a = 1;
					s = p / 4;
				} else s = p / (2 * Math.PI) * Math.asin(1 / a);
				return -(a * Math.pow(2, 10 * (t -= 1)) * Math.sin((t * 1 - s) * (2 * Math.PI) / p));
			},
			easeOutElastic: function (t) {
				var s = 1.70158;
				var p = 0;
				var a = 1;
				if (t === 0) return 0;
				if ((t /= 1) == 1) return 1;
				if (!p) p = 1 * 0.3;
				if (a < Math.abs(1)) {
					a = 1;
					s = p / 4;
				} else s = p / (2 * Math.PI) * Math.asin(1 / a);
				return a * Math.pow(2, -10 * t) * Math.sin((t * 1 - s) * (2 * Math.PI) / p) + 1;
			},
			easeInOutElastic: function (t) {
				var s = 1.70158;
				var p = 0;
				var a = 1;
				if (t === 0) return 0;
				if ((t /= 1 / 2) == 2) return 1;
				if (!p) p = 1 * (0.3 * 1.5);
				if (a < Math.abs(1)) {
					a = 1;
					s = p / 4;
				} else s = p / (2 * Math.PI) * Math.asin(1 / a);
				if (t < 1) return -0.5 * (a * Math.pow(2, 10 * (t -= 1)) * Math.sin((t * 1 - s) * (2 * Math.PI) / p));
				return a * Math.pow(2, -10 * (t -= 1)) * Math.sin((t * 1 - s) * (2 * Math.PI) / p) * 0.5 + 1;
			},
			easeInBack: function (t) {
				var s = 1.70158;
				return 1 * (t /= 1) * t * ((s + 1) * t - s);
			},
			easeOutBack: function (t) {
				var s = 1.70158;
				return 1 * ((t = t / 1 - 1) * t * ((s + 1) * t + s) + 1);
			},
			easeInOutBack: function (t) {
				var s = 1.70158;
				if ((t /= 1 / 2) < 1) return 1 / 2 * (t * t * (((s *= (1.525)) + 1) * t - s));
				return 1 / 2 * ((t -= 2) * t * (((s *= (1.525)) + 1) * t + s) + 2);
			},
			easeInBounce: function (t) {
				return 1 - easingEffects.easeOutBounce(1 - t);
			},
			easeOutBounce: function (t) {
				if ((t /= 1) < (1 / 2.75)) {
					return 1 * (7.5625 * t * t);
				} else if (t < (2 / 2.75)) {
					return 1 * (7.5625 * (t -= (1.5 / 2.75)) * t + 0.75);
				} else if (t < (2.5 / 2.75)) {
					return 1 * (7.5625 * (t -= (2.25 / 2.75)) * t + 0.9375);
				} else {
					return 1 * (7.5625 * (t -= (2.625 / 2.75)) * t + 0.984375);
				}
			},
			easeInOutBounce: function (t) {
				if (t < 1 / 2) return easingEffects.easeInBounce(t * 2) * 0.5;
				return easingEffects.easeOutBounce(t * 2 - 1) * 0.5 + 1 * 0.5;
			}
		},
		//Request animation polyfill - http://www.paulirish.com/2011/requestanimationframe-for-smart-animating/
		requestAnimFrame = helpers.requestAnimFrame = (function(){
			return window.requestAnimationFrame ||
				window.webkitRequestAnimationFrame ||
				window.mozRequestAnimationFrame ||
				window.oRequestAnimationFrame ||
				window.msRequestAnimationFrame ||
				function(callback) {
					return window.setTimeout(callback, 1000 / 60);
				};
		})(),
		cancelAnimFrame = helpers.cancelAnimFrame = (function(){
			return window.cancelAnimationFrame ||
				window.webkitCancelAnimationFrame ||
				window.mozCancelAnimationFrame ||
				window.oCancelAnimationFrame ||
				window.msCancelAnimationFrame ||
				function(callback) {
					return window.clearTimeout(callback, 1000 / 60);
				};
		})(),
		animationLoop = helpers.animationLoop = function(callback,totalSteps,easingString,onProgress,onComplete,chartInstance){

			var currentStep = 0,
				easingFunction = easingEffects[easingString] || easingEffects.linear;

			var animationFrame = function(){
				currentStep++;
				var stepDecimal = currentStep/totalSteps;
				var easeDecimal = easingFunction(stepDecimal);

				callback.call(chartInstance,easeDecimal,stepDecimal, currentStep);
				onProgress.call(chartInstance,easeDecimal,stepDecimal);
				if (currentStep < totalSteps){
					chartInstance.animationFrame = requestAnimFrame(animationFrame);
				} else{
					onComplete.apply(chartInstance);
				}
			};
			requestAnimFrame(animationFrame);
		},
		//-- DOM methods
		getRelativePosition = helpers.getRelativePosition = function(evt){
			var mouseX, mouseY;
			var e = evt.originalEvent || evt,
				canvas = evt.currentTarget || evt.srcElement,
				boundingRect = canvas.getBoundingClientRect();

			if (e.touches){
				mouseX = e.touches[0].clientX - boundingRect.left;
				mouseY = e.touches[0].clientY - boundingRect.top;

			}
			else{
				mouseX = e.clientX - boundingRect.left;
				mouseY = e.clientY - boundingRect.top;
			}

			return {
				x : mouseX,
				y : mouseY
			};

		},
		addEvent = helpers.addEvent = function(node,eventType,method){
			if (node.addEventListener){
				node.addEventListener(eventType,method);
			} else if (node.attachEvent){
				node.attachEvent("on"+eventType, method);
			} else {
				node["on"+eventType] = method;
			}
		},
		removeEvent = helpers.removeEvent = function(node, eventType, handler){
			if (node.removeEventListener){
				node.removeEventListener(eventType, handler, false);
			} else if (node.detachEvent){
				node.detachEvent("on"+eventType,handler);
			} else{
				node["on" + eventType] = noop;
			}
		},
		bindEvents = helpers.bindEvents = function(chartInstance, arrayOfEvents, handler){
			// Create the events object if it's not already present
			if (!chartInstance.events) chartInstance.events = {};

			each(arrayOfEvents,function(eventName){
				chartInstance.events[eventName] = function(){
					handler.apply(chartInstance, arguments);
				};
				addEvent(chartInstance.chart.canvas,eventName,chartInstance.events[eventName]);
			});
		},
		unbindEvents = helpers.unbindEvents = function (chartInstance, arrayOfEvents) {
			each(arrayOfEvents, function(handler,eventName){
				removeEvent(chartInstance.chart.canvas, eventName, handler);
			});
		},
		getMaximumWidth = helpers.getMaximumWidth = function(domNode){
			var container = domNode.parentNode;
			// TODO = check cross browser stuff with this.
			return container.clientWidth;
		},
		getMaximumHeight = helpers.getMaximumHeight = function(domNode){
			var container = domNode.parentNode;
			// TODO = check cross browser stuff with this.
			return container.clientHeight;
		},
		getMaximumSize = helpers.getMaximumSize = helpers.getMaximumWidth, // legacy support
		retinaScale = helpers.retinaScale = function(chart){
			var ctx = chart.ctx,
				width = chart.canvas.width,
				height = chart.canvas.height;

			if (window.devicePixelRatio) {
				ctx.canvas.style.width = width + "px";
				ctx.canvas.style.height = height + "px";
				ctx.canvas.height = height * window.devicePixelRatio;
				ctx.canvas.width = width * window.devicePixelRatio;
				ctx.scale(window.devicePixelRatio, window.devicePixelRatio);
			}
		},
		//-- Canvas methods
		clear = helpers.clear = function(chart){
			chart.ctx.clearRect(0,0,chart.width,chart.height);
		},
		fontString = helpers.fontString = function(pixelSize,fontStyle,fontFamily){
			return fontStyle + " " + pixelSize+"px " + fontFamily;
		},
		longestText = helpers.longestText = function(ctx,font,arrayOfStrings){
			ctx.font = font;
			var longest = 0;
			each(arrayOfStrings,function(string){
				var textWidth = ctx.measureText(string).width;
				longest = (textWidth > longest) ? textWidth : longest;
			});
			return longest;
		},
		drawRoundedRectangle = helpers.drawRoundedRectangle = function(ctx,x,y,width,height,radius){
			ctx.beginPath();
			ctx.moveTo(x + radius, y);
			ctx.lineTo(x + width - radius, y);
			ctx.quadraticCurveTo(x + width, y, x + width, y + radius);
			ctx.lineTo(x + width, y + height - radius);
			ctx.quadraticCurveTo(x + width, y + height, x + width - radius, y + height);
			ctx.lineTo(x + radius, y + height);
			ctx.quadraticCurveTo(x, y + height, x, y + height - radius);
			ctx.lineTo(x, y + radius);
			ctx.quadraticCurveTo(x, y, x + radius, y);
			ctx.closePath();
		};


	//Store a reference to each instance - allowing us to globally resize chart instances on window resize.
	//Destroy method on the chart will remove the instance of the chart from this reference.
	Chart.instances = {};

	Chart.Type = function(data,options,chart){
		this.options = options;
		this.chart = chart;
		this.id = uid();
		//Add the chart instance to the global namespace
		Chart.instances[this.id] = this;

		// Initialize is always called when a chart type is created
		// By default it is a no op, but it should be extended
		if (options.responsive){
			this.resize();
		}
		this.initialize.call(this,data);
	};

	//Core methods that'll be a part of every chart type
	extend(Chart.Type.prototype,{
		initialize : function(){return this;},
		clear : function(){
			clear(this.chart);
			return this;
		},
		stop : function(){
			// Stops any current animation loop occuring
			cancelAnimFrame(this.animationFrame);
			return this;
		},
		resize : function(callback){
			this.stop();
			var canvas = this.chart.canvas,
				newWidth = getMaximumWidth(this.chart.canvas),
				newHeight = this.options.maintainAspectRatio ? newWidth / this.chart.aspectRatio : getMaximumHeight(this.chart.canvas);

			canvas.width = this.chart.width = newWidth;
			canvas.height = this.chart.height = newHeight;

			retinaScale(this.chart);

			if (typeof callback === "function"){
				callback.apply(this, Array.prototype.slice.call(arguments, 1));
			}
			return this;
		},
		reflow : noop,
		render : function(reflow){
			if (reflow){
				this.reflow();
			}
			if (this.options.animation && !reflow){
				helpers.animationLoop(
					this.draw,
					this.options.animationSteps,
					this.options.animationEasing,
					this.options.onAnimationProgress,
					this.options.onAnimationComplete,
					this
				);
			}
			else{
				this.draw();
				this.options.onAnimationComplete.call(this);
			}
			return this;
		},
		generateLegend : function(){
			return template(this.options.legendTemplate,this);
		},
		destroy : function(){
			this.clear();
			unbindEvents(this, this.events);
			var canvas = this.chart.canvas;

			// Reset canvas height/width attributes starts a fresh with the canvas context
			canvas.width = this.chart.width;
			canvas.height = this.chart.height;

			// < IE9 doesn't support removeProperty
			if (canvas.style.removeProperty) {
				canvas.style.removeProperty('width');
				canvas.style.removeProperty('height');
			} else {
				canvas.style.removeAttribute('width');
				canvas.style.removeAttribute('height');
			}

			delete Chart.instances[this.id];
		},
		showTooltip : function(ChartElements, forceRedraw){
			// Only redraw the chart if we've actually changed what we're hovering on.
			if (typeof this.activeElements === 'undefined') this.activeElements = [];

			var isChanged = (function(Elements){
				var changed = false;

				if (Elements.length !== this.activeElements.length){
					changed = true;
					return changed;
				}

				each(Elements, function(element, index){
					if (element !== this.activeElements[index]){
						changed = true;
					}
				}, this);
				return changed;
			}).call(this, ChartElements);

			if (!isChanged && !forceRedraw){
				return;
			}
			else{
				this.activeElements = ChartElements;
			}
			this.draw();
			if(this.options.customTooltips){
				this.options.customTooltips(false);
			}
			if (ChartElements.length > 0){
				// If we have multiple datasets, show a MultiTooltip for all of the data points at that index
				if (this.datasets && this.datasets.length > 1) {
					var dataArray,
						dataIndex;

					for (var i = this.datasets.length - 1; i >= 0; i--) {
						dataArray = this.datasets[i].points || this.datasets[i].bars || this.datasets[i].segments;
						dataIndex = indexOf(dataArray, ChartElements[0]);
						if (dataIndex !== -1){
							break;
						}
					}
					var tooltipLabels = [],
						tooltipColors = [],
						medianPosition = (function(index) {

							// Get all the points at that particular index
							var Elements = [],
								dataCollection,
								xPositions = [],
								yPositions = [],
								xMax,
								yMax,
								xMin,
								yMin;
							helpers.each(this.datasets, function(dataset){
								dataCollection = dataset.points || dataset.bars || dataset.segments;
								if (dataCollection[dataIndex] && dataCollection[dataIndex].hasValue()){
									Elements.push(dataCollection[dataIndex]);
								}
							});

							helpers.each(Elements, function(element) {
								xPositions.push(element.x);
								yPositions.push(element.y);


								//Include any colour information about the element
								tooltipLabels.push(helpers.template(this.options.multiTooltipTemplate, element));
								tooltipColors.push({
									fill: element._saved.fillColor || element.fillColor,
									stroke: element._saved.strokeColor || element.strokeColor
								});

							}, this);

							yMin = min(yPositions);
							yMax = max(yPositions);

							xMin = min(xPositions);
							xMax = max(xPositions);

							return {
								x: (xMin > this.chart.width/2) ? xMin : xMax,
								y: (yMin + yMax)/2
							};
						}).call(this, dataIndex);

					new Chart.MultiTooltip({
						x: medianPosition.x,