text: /* global window: false */
  /* global document: false */
  'use strict';
  
  var color = require('chartjs-color');
  
  module.exports = function(Chart) {
  	// Global Chart helpers object for utility methods and classes
  	var helpers = Chart.helpers = {};
  
  	// -- Basic js utility methods
  	helpers.each = function(loopable, callback, self, reverse) {
  		// Check to see if null or undefined firstly.
  		var i, len;
  		if (helpers.isArray(loopable)) {
  			len = loopable.length;
  			if (reverse) {
  				for (i = len - 1; i >= 0; i--) {
  					callback.call(self, loopable[i], i);
  				}
  			} else {
  				for (i = 0; i < len; i++) {
  					callback.call(self, loopable[i], i);
  				}
  			}
  		} else if (typeof loopable === 'object') {
  			var keys = Object.keys(loopable);
  			len = keys.length;
  			for (i = 0; i < len; i++) {
  				callback.call(self, loopable[keys[i]], keys[i]);
  			}
  		}
  	};
  	helpers.clone = function(obj) {
  		var objClone = {};
  		helpers.each(obj, function(value, key) {
  			if (helpers.isArray(value)) {
  				objClone[key] = value.slice(0);
  			} else if (typeof value === 'object' && value !== null) {
  				objClone[key] = helpers.clone(value);
  			} else {
  				objClone[key] = value;
  			}
  		});
  		return objClone;
  	};
  	helpers.extend = function(base) {
  		var setFn = function(value, key) {
  			base[key] = value;
  		};
  		for (var i = 1, ilen = arguments.length; i < ilen; i++) {
  			helpers.each(arguments[i], setFn);
  		}
  		return base;
  	};
  	// Need a special merge function to chart configs since they are now grouped
  	helpers.configMerge = function(_base) {
  		var base = helpers.clone(_base);
  		helpers.each(Array.prototype.slice.call(arguments, 1), function(extension) {
  			helpers.each(extension, function(value, key) {
  				var baseHasProperty = base.hasOwnProperty(key);
  				var baseVal = baseHasProperty ? base[key] : {};
  
  				if (key === 'scales') {
  					// Scale config merging is complex. Add our own function here for that
  					base[key] = helpers.scaleMerge(baseVal, value);
  				} else if (key === 'scale') {
  					// Used in polar area & radar charts since there is only one scale
  					base[key] = helpers.configMerge(baseVal, Chart.scaleService.getScaleDefaults(value.type), value);
  				} else if (baseHasProperty
  						&& typeof baseVal === 'object'
  						&& !helpers.isArray(baseVal)
  						&& baseVal !== null
  						&& typeof value === 'object'
  						&& !helpers.isArray(value)) {
  					// If we are overwriting an object with an object, do a merge of the properties.
  					base[key] = helpers.configMerge(baseVal, value);
  				} else {
  					// can just overwrite the value in this case
  					base[key] = value;
  				}
  			});
  		});
  
  		return base;
  	};
  	helpers.scaleMerge = function(_base, extension) {
  		var base = helpers.clone(_base);
  
  		helpers.each(extension, function(value, key) {
  			if (key === 'xAxes' || key === 'yAxes') {
  				// These properties are arrays of items
  				if (base.hasOwnProperty(key)) {
  					helpers.each(value, function(valueObj, index) {
  						var axisType = helpers.getValueOrDefault(valueObj.type, key === 'xAxes' ? 'category' : 'linear');
  						var axisDefaults = Chart.scaleService.getScaleDefaults(axisType);
  						if (index >= base[key].length || !base[key][index].type) {
  							base[key].push(helpers.configMerge(axisDefaults, valueObj));
  						} else if (valueObj.type && valueObj.type !== base[key][index].type) {
  							// Type changed. Bring in the new defaults before we bring in valueObj so that valueObj can override the correct scale defaults
  							base[key][index] = helpers.configMerge(base[key][index], axisDefaults, valueObj);
  						} else {
  							// Type is the same
  							base[key][index] = helpers.configMerge(base[key][index], valueObj);
  						}
  					});
  				} else {
  					base[key] = [];
  					helpers.each(value, function(valueObj) {
  						var axisType = helpers.getValueOrDefault(valueObj.type, key === 'xAxes' ? 'category' : 'linear');
  						base[key].push(helpers.configMerge(Chart.scaleService.getScaleDefaults(axisType), valueObj));
  					});
  				}
  			} else if (base.hasOwnProperty(key) && typeof base[key] === 'object' && base[key] !== null && typeof value === 'object') {
  				// If we are overwriting an object with an object, do a merge of the properties.
  				base[key] = helpers.configMerge(base[key], value);
  
  			} else {
  				// can just overwrite the value in this case
  				base[key] = value;
  			}
  		});
  
  		return base;
  	};
  	helpers.getValueAtIndexOrDefault = function(value, index, defaultValue) {
  		if (value === undefined || value === null) {
  			return defaultValue;
  		}
  
  		if (helpers.isArray(value)) {
  			return index < value.length ? value[index] : defaultValue;
  		}
  
  		return value;
  	};
  	helpers.getValueOrDefault = function(value, defaultValue) {
  		return value === undefined ? defaultValue : value;
  	};
  	helpers.indexOf = Array.prototype.indexOf?
  		function(array, item) {
  			return array.indexOf(item);
  		}:
  		function(array, item) {
  			for (var i = 0, ilen = array.length; i < ilen; ++i) {
  				if (array[i] === item) {
  					return i;
  				}
  			}
  			return -1;
  		};
  	helpers.where = function(collection, filterCallback) {
  		if (helpers.isArray(collection) && Array.prototype.filter) {
  			return collection.filter(filterCallback);
  		}
  		var filtered = [];
  
  		helpers.each(collection, function(item) {
  			if (filterCallback(item)) {
  				filtered.push(item);
  			}
  		});
  
  		return filtered;
  	};
  	helpers.findIndex = Array.prototype.findIndex?
  		function(array, callback, scope) {
  			return array.findIndex(callback, scope);
  		} :
  		function(array, callback, scope) {
  			scope = scope === undefined? array : scope;
  			for (var i = 0, ilen = array.length; i < ilen; ++i) {
  				if (callback.call(scope, array[i], i, array)) {
  					return i;
  				}
  			}
  			return -1;
  		};
  	helpers.findNextWhere = function(arrayToSearch, filterCallback, startIndex) {
  		// Default to start of the array
  		if (startIndex === undefined || startIndex === null) {
  			startIndex = -1;
  		}
  		for (var i = startIndex + 1; i < arrayToSearch.length; i++) {
  			var currentItem = arrayToSearch[i];
  			if (filterCallback(currentItem)) {
  				return currentItem;
  			}
  		}
  	};
  	helpers.findPreviousWhere = function(arrayToSearch, filterCallback, startIndex) {
  		// Default to end of the array
  		if (startIndex === undefined || startIndex === null) {
  			startIndex = arrayToSearch.length;
  		}
  		for (var i = startIndex - 1; i >= 0; i--) {
  			var currentItem = arrayToSearch[i];
  			if (filterCallback(currentItem)) {
  				return currentItem;
  			}
  		}
  	};
  	helpers.inherits = function(extensions) {
  		// Basic javascript inheritance based on the model created in Backbone.js
  		var me = this;
  		var ChartElement = (extensions && extensions.hasOwnProperty('constructor')) ? extensions.constructor : function() {
  			return me.apply(this, arguments);
  		};
  
  		var Surrogate = function() {
  			this.constructor = ChartElement;
  		};
  		Surrogate.prototype = me.prototype;
  		ChartElement.prototype = new Surrogate();
  
  		ChartElement.extend = helpers.inherits;
  
  		if (extensions) {
  			helpers.extend(ChartElement.prototype, extensions);
  		}
  
  		ChartElement.__super__ = me.prototype;
  
  		return ChartElement;
  	};
  	helpers.noop = function() {};
  	helpers.uid = (function() {
  		var id = 0;
  		return function() {
  			return id++;
  		};
  	}());
  	// -- Math methods
  	helpers.isNumber = function(n) {
  		return !isNaN(parseFloat(n)) && isFinite(n);
  	};
  	helpers.almostEquals = function(x, y, epsilon) {
  		return Math.abs(x - y) < epsilon;
  	};
  	helpers.max = function(array) {
  		return array.reduce(function(max, value) {
  			if (!isNaN(value)) {
  				return Math.max(max, value);
  			}
  			return max;
  		}, Number.NEGATIVE_INFINITY);
  	};
  	helpers.min = function(array) {
  		return array.reduce(function(min, value) {
  			if (!isNaN(value)) {
  				return Math.min(min, value);
  			}
  			return min;
  		}, Number.POSITIVE_INFINITY);
  	};
  	helpers.sign = Math.sign?
  		function(x) {
  			return Math.sign(x);
  		} :
  		function(x) {
  			x = +x; // convert to a number
  			if (x === 0 || isNaN(x)) {
  				return x;
  			}
  			return x > 0 ? 1 : -1;
  		};
  	helpers.log10 = Math.log10?
  		function(x) {
  			return Math.log10(x);
  		} :
  		function(x) {
  			return Math.log(x) / Math.LN10;
  		};
  	helpers.toRadians = function(degrees) {
  		return degrees * (Math.PI / 180);
  	};
  	helpers.toDegrees = function(radians) {
  		return radians * (180 / Math.PI);
  	};
  	// Gets the angle from vertical upright to the point about a centre.
  	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.atan2(distanceFromYCenter, distanceFromXCenter);
  
  		if (angle < (-0.5 * Math.PI)) {
  			angle += 2.0 * Math.PI; // make sure the returned angle is in the range of (-PI/2, 3PI/2]
  		}
  
  		return {
  			angle: angle,
  			distance: radialDistanceFromCenter
  		};
  	};
  	helpers.distanceBetweenPoints = function(pt1, pt2) {
  		return Math.sqrt(Math.pow(pt2.x - pt1.x, 2) + Math.pow(pt2.y - pt1.y, 2));
  	};
  	helpers.aliasPixel = function(pixelWidth) {
  		return (pixelWidth % 2 === 0) ? 0 : 0.5;
  	};
  	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
  
  		// This function must also respect "skipped" points
  
  		var previous = firstPoint.skip ? middlePoint : firstPoint,
  			current = middlePoint,
  			next = afterPoint.skip ? middlePoint : afterPoint;
  
  		var d01 = Math.sqrt(Math.pow(current.x - previous.x, 2) + Math.pow(current.y - previous.y, 2));
  		var d12 = Math.sqrt(Math.pow(next.x - current.x, 2) + Math.pow(next.y - current.y, 2));
  
  		var s01 = d01 / (d01 + d12);
  		var s12 = d12 / (d01 + d12);
  
  		// If all points are the same, s01 & s02 will be inf
  		s01 = isNaN(s01) ? 0 : s01;
  		s12 = isNaN(s12) ? 0 : s12;
  
  		var fa = t * s01; // scaling factor for triangle Ta
  		var fb = t * s12;
  
  		return {
  			previous: {
  				x: current.x - fa * (next.x - previous.x),
  				y: current.y - fa * (next.y - previous.y)
  			},
  			next: {
  				x: current.x + fb * (next.x - previous.x),
  				y: current.y + fb * (next.y - previous.y)
  			}
  		};
  	};
  	helpers.EPSILON = Number.EPSILON || 1e-14;
  	helpers.splineCurveMonotone = function(points) {
  		// This function calculates Bézier control points in a similar way than |splineCurve|,
  		// but preserves monotonicity of the provided data and ensures no local extremums are added
  		// between the dataset discrete points due to the interpolation.
  		// See : https://en.wikipedia.org/wiki/Monotone_cubic_interpolation
  
  		var pointsWithTangents = (points || []).map(function(point) {
  			return {
  				model: point._model,
  				deltaK: 0,
  				mK: 0
  			};
  		});
  
  		// Calculate slopes (deltaK) and initialize tangents (mK)
  		var pointsLen = pointsWithTangents.length;
  		var i, pointBefore, pointCurrent, pointAfter;
  		for (i = 0; i < pointsLen; ++i) {
  			pointCurrent = pointsWithTangents[i];
  			if (pointCurrent.model.skip) {
  				continue;
  			}
  
  			pointBefore = i > 0 ? pointsWithTangents[i - 1] : null;
  			pointAfter = i < pointsLen - 1 ? pointsWithTangents[i + 1] : null;
  			if (pointAfter && !pointAfter.model.skip) {
  				pointCurrent.deltaK = (pointAfter.model.y - pointCurrent.model.y) / (pointAfter.model.x - pointCurrent.model.x);
  			}
  
  			if (!pointBefore || pointBefore.model.skip) {
  				pointCurrent.mK = pointCurrent.deltaK;
  			} else if (!pointAfter || pointAfter.model.skip) {
  				pointCurrent.mK = pointBefore.deltaK;
  			} else if (this.sign(pointBefore.deltaK) !== this.sign(pointCurrent.deltaK)) {
  				pointCurrent.mK = 0;
  			} else {
  				pointCurrent.mK = (pointBefore.deltaK + pointCurrent.deltaK) / 2;
  			}
  		}
  
  		// Adjust tangents to ensure monotonic properties
  		var alphaK, betaK, tauK, squaredMagnitude;
  		for (i = 0; i < pointsLen - 1; ++i) {
  			pointCurrent = pointsWithTangents[i];
  			pointAfter = pointsWithTangents[i + 1];
  			if (pointCurrent.model.skip || pointAfter.model.skip) {
  				continue;
  			}
  
  			if (helpers.almostEquals(pointCurrent.deltaK, 0, this.EPSILON)) {
  				pointCurrent.mK = pointAfter.mK = 0;
  				continue;
  			}
  
  			alphaK = pointCurrent.mK / pointCurrent.deltaK;
  			betaK = pointAfter.mK / pointCurrent.deltaK;
  			squaredMagnitude = Math.pow(alphaK, 2) + Math.pow(betaK, 2);
  			if (squaredMagnitude <= 9) {
  				continue;
  			}
  
  			tauK = 3 / Math.sqrt(squaredMagnitude);
  			pointCurrent.mK = alphaK * tauK * pointCurrent.deltaK;
  			pointAfter.mK = betaK * tauK * pointCurrent.deltaK;
  		}
  
  		// Compute control points
  		var deltaX;
  		for (i = 0; i < pointsLen; ++i) {
  			pointCurrent = pointsWithTangents[i];
  			if (pointCurrent.model.skip) {
  				continue;
  			}
  
  			pointBefore = i > 0 ? pointsWithTangents[i - 1] : null;
  			pointAfter = i < pointsLen - 1 ? pointsWithTangents[i + 1] : null;
  			if (pointBefore && !pointBefore.model.skip) {
  				deltaX = (pointCurrent.model.x - pointBefore.model.x) / 3;
  				pointCurrent.model.controlPointPreviousX = pointCurrent.model.x - deltaX;
  				pointCurrent.model.controlPointPreviousY = pointCurrent.model.y - deltaX * pointCurrent.mK;
  			}
  			if (pointAfter && !pointAfter.model.skip) {
  				deltaX = (pointAfter.model.x - pointCurrent.model.x) / 3;
  				pointCurrent.model.controlPointNextX = pointCurrent.model.x + deltaX;
  				pointCurrent.model.controlPointNextY = pointCurrent.model.y + deltaX * pointCurrent.mK;
  			}
  		}
  	};
  	helpers.nextItem = function(collection, index, loop) {
  		if (loop) {
  			return index >= collection.length - 1 ? collection[0] : collection[index + 1];
  		}
  		return index >= collection.length - 1 ? collection[collection.length - 1] : collection[index + 1];
  	};
  	helpers.previousItem = function(collection, index, loop) {
  		if (loop) {
  			return index <= 0 ? collection[collection.length - 1] : collection[index - 1];
  		}
  		return index <= 0 ? collection[0] : collection[index - 1];
  	};
  	// Implementation of the nice number algorithm used in determining where axis labels will go
  	helpers.niceNum = function(range, round) {
  		var exponent = Math.floor(helpers.log10(range));
  		var fraction = range / Math.pow(10, exponent);
  		var niceFraction;
  
  		if (round) {
  			if (fraction < 1.5) {
  				niceFraction = 1;
  			} else if (fraction < 3) {
  				niceFraction = 2;
  			} else if (fraction < 7) {
  				niceFraction = 5;
  			} else {
  				niceFraction = 10;
  			}
  		} else if (fraction <= 1.0) {
  			niceFraction = 1;
  		} else if (fraction <= 2) {
  			niceFraction = 2;
  		} else if (fraction <= 5) {
  			niceFraction = 5;
  		} else {
  			niceFraction = 10;
  		}
  
  		return niceFraction * Math.pow(10, exponent);
  	};
  	// Easing functions adapted from Robert Penner's easing equations
  	// http://www.robertpenner.com/easing/
  	var 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);
  			}
  			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/
  	helpers.requestAnimFrame = (function() {
  		return window.requestAnimationFrame ||
  			window.webkitRequestAnimationFrame ||
  			window.mozRequestAnimationFrame ||
  			window.oRequestAnimationFrame ||
  			window.msRequestAnimationFrame ||
  			function(callback) {
  				return window.setTimeout(callback, 1000 / 60);
  			};
  	}());
  	// -- DOM methods
  	helpers.getRelativePosition = function(evt, chart) {
  		var mouseX, mouseY;
  		var e = evt.originalEvent || evt,
  			canvas = evt.currentTarget || evt.srcElement,
  			boundingRect = canvas.getBoundingClientRect();
  
  		var touches = e.touches;
  		if (touches && touches.length > 0) {
  			mouseX = touches[0].clientX;
  			mouseY = touches[0].clientY;
  
  		} else {
  			mouseX = e.clientX;
  			mouseY = e.clientY;
  		}
  
  		// Scale mouse coordinates into canvas coordinates
  		// by following the pattern laid out by 'jerryj' in the comments of
  		// http://www.html5canvastutorials.com/advanced/html5-canvas-mouse-coordinates/
  		var paddingLeft = parseFloat(helpers.getStyle(canvas, 'padding-left'));
  		var paddingTop = parseFloat(helpers.getStyle(canvas, 'padding-top'));
  		var paddingRight = parseFloat(helpers.getStyle(canvas, 'padding-right'));
  		var paddingBottom = parseFloat(helpers.getStyle(canvas, 'padding-bottom'));
  		var width = boundingRect.right - boundingRect.left - paddingLeft - paddingRight;
  		var height = boundingRect.bottom - boundingRect.top - paddingTop - paddingBottom;
  
  		// We divide by the current device pixel ratio, because the canvas is scaled up by that amount in each direction. However
  		// the backend model is in unscaled coordinates. Since we are going to deal with our model coordinates, we go back here
  		mouseX = Math.round((mouseX - boundingRect.left - paddingLeft) / (width) * canvas.width / chart.currentDevicePixelRatio);
  		mouseY = Math.round((mouseY - boundingRect.top - paddingTop) / (height) * canvas.height / chart.currentDevicePixelRatio);
  
  		return {
  			x: mouseX,
  			y: mouseY
  		};
  
  	};
  	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;
  		}
  	};
  	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] = helpers.noop;
  		}
  	};
  	helpers.bindEvents = function(chartInstance, arrayOfEvents, handler) {
  		// Create the events object if it's not already present
  		var events = chartInstance.events = chartInstance.events || {};
  
  		helpers.each(arrayOfEvents, function(eventName) {
  			events[eventName] = function() {
  				handler.apply(chartInstance, arguments);
  			};
  			helpers.addEvent(chartInstance.chart.canvas, eventName, events[eventName]);
  		});
  	};
  	helpers.unbindEvents = function(chartInstance, arrayOfEvents) {
  		var canvas = chartInstance.chart.canvas;
  		helpers.each(arrayOfEvents, function(handler, eventName) {
  			helpers.removeEvent(canvas, eventName, handler);
  		});
  	};
  
  	// Private helper function to convert max-width/max-height values that may be percentages into a number
  	function parseMaxStyle(styleValue, node, parentProperty) {
  		var valueInPixels;
  		if (typeof(styleValue) === 'string') {
  			valueInPixels = parseInt(styleValue, 10);
  
  			if (styleValue.indexOf('%') !== -1) {
  				// percentage * size in dimension
  				valueInPixels = valueInPixels / 100 * node.parentNode[parentProperty];
  			}
  		} else {
  			valueInPixels = styleValue;
  		}
  
  		return valueInPixels;
  	}
  
  	/**
  	 * Returns if the given value contains an effective constraint.
  	 * @private
  	 */
  	function isConstrainedValue(value) {
  		return value !== undefined && value !== null && value !== 'none';
  	}
  
  	// Private helper to get a constraint dimension
  	// @param domNode : the node to check the constraint on
  	// @param maxStyle : the style that defines the maximum for the direction we are using (maxWidth / maxHeight)
  	// @param percentageProperty : property of parent to use when calculating width as a percentage
  	// @see http://www.nathanaeljones.com/blog/2013/reading-max-width-cross-browser
  	function getConstraintDimension(domNode, maxStyle, percentageProperty) {
  		var view = document.defaultView;
  		var parentNode = domNode.parentNode;
  		var constrainedNode = view.getComputedStyle(domNode)[maxStyle];
  		var constrainedContainer = view.getComputedStyle(parentNode)[maxStyle];
  		var hasCNode = isConstrainedValue(constrainedNode);
  		var hasCContainer = isConstrainedValue(constrainedContainer);
  		var infinity = Number.POSITIVE_INFINITY;
  
  		if (hasCNode || hasCContainer) {
  			return Math.min(
  				hasCNode? parseMaxStyle(constrainedNode, domNode, percentageProperty) : infinity,
  				hasCContainer? parseMaxStyle(constrainedContainer, parentNode, percentageProperty) : infinity);
  		}
  
  		return 'none';
  	}
  	// returns Number or undefined if no constraint
  	helpers.getConstraintWidth = function(domNode) {
  		return getConstraintDimension(domNode, 'max-width', 'clientWidth');
  	};
  	// returns Number or undefined if no constraint
  	helpers.getConstraintHeight = function(domNode) {
  		return getConstraintDimension(domNode, 'max-height', 'clientHeight');
  	};
  	helpers.getMaximumWidth = function(domNode) {
  		var container = domNode.parentNode;
  		var paddingLeft = parseInt(helpers.getStyle(container, 'padding-left'), 10);
  		var paddingRight = parseInt(helpers.getStyle(container, 'padding-right'), 10);
  		var w = container.clientWidth - paddingLeft - paddingRight;
  		var cw = helpers.getConstraintWidth(domNode);
  		return isNaN(cw)? w : Math.min(w, cw);
  	};
  	helpers.getMaximumHeight = function(domNode) {
  		var container = domNode.parentNode;
  		var paddingTop = parseInt(helpers.getStyle(container, 'padding-top'), 10);
  		var paddingBottom = parseInt(helpers.getStyle(container, 'padding-bottom'), 10);
  		var h = container.clientHeight - paddingTop - paddingBottom;
  		var ch = helpers.getConstraintHeight(domNode);
  		return isNaN(ch)? h : Math.min(h, ch);
  	};
  	helpers.getStyle = function(el, property) {
  		return el.currentStyle ?
  			el.currentStyle[property] :
  			document.defaultView.getComputedStyle(el, null).getPropertyValue(property);
  	};
  	helpers.retinaScale = function(chart) {
  		var pixelRatio = chart.currentDevicePixelRatio = window.devicePixelRatio || 1;
  		if (pixelRatio === 1) {
  			return;
  		}
  
  		var canvas = chart.canvas;
  		var height = chart.height;
  		var width = chart.width;
  
  		canvas.height = height * pixelRatio;
  		canvas.width = width * pixelRatio;
  		chart.ctx.scale(pixelRatio, pixelRatio);
  
  		// If no style has been set on the canvas, the render size is used as display size,
  		// making the chart visually bigger, so let's enforce it to the "correct" values.
  		// See https://github.com/chartjs/Chart.js/issues/3575
  		canvas.style.height = height + 'px';
  		canvas.style.width = width + 'px';
  	};
  	// -- Canvas methods
  	helpers.clear = function(chart) {
  		chart.ctx.clearRect(0, 0, chart.width, chart.height);
  	};
  	helpers.fontString = function(pixelSize, fontStyle, fontFamily) {
  		return fontStyle + ' ' + pixelSize + 'px ' + fontFamily;
  	};
  	helpers.longestText = function(ctx, font, arrayOfThings, cache) {
  		cache = cache || {};
  		var data = cache.data = cache.data || {};
  		var gc = cache.garbageCollect = cache.garbageCollect || [];
  
  		if (cache.font !== font) {
  			data = cache.data = {};
  			gc = cache.garbageCollect = [];
  			cache.font = font;
  		}
  
  		ctx.font = font;
  		var longest = 0;
  		helpers.each(arrayOfThings, function(thing) {
  			// Undefined strings and arrays should not be measured
  			if (thing !== undefined && thing !== null && helpers.isArray(thing) !== true) {
  				longest = helpers.measureText(ctx, data, gc, longest, thing);
  			} else if (helpers.isArray(thing)) {
  				// if it is an array lets measure each element
  				// to do maybe simplify this function a bit so we can do this more recursively?
  				helpers.each(thing, function(nestedThing) {
  					// Undefined strings and arrays should not be measured
  					if (nestedThing !== undefined && nestedThing !== null && !helpers.isArray(nestedThing)) {
  						longest = helpers.measureText(ctx, data, gc, longest, nestedThing);
  					}
  				});
  			}
  		});
  
  		var gcLen = gc.length / 2;
  		if (gcLen > arrayOfThings.length) {
  			for (var i = 0; i < gcLen; i++) {
  				delete data[gc[i]];
  			}
  			gc.splice(0, gcLen);
  		}
  		return longest;
  	};
  	helpers.measureText = function(ctx, data, gc, longest, string) {
  		var textWidth = data[string];
  		if (!textWidth) {
  			textWidth = data[string] = ctx.measureText(string).width;
  			gc.push(string);
  		}
  		if (textWidth > longest) {
  			longest = textWidth;
  		}
  		return longest;
  	};
  	helpers.numberOfLabelLines = function(arrayOfThings) {
  		var numberOfLines = 1;
  		helpers.each(arrayOfThings, function(thing) {
  			if (helpers.isArray(thing)) {
  				if (thing.length > numberOfLines) {
  					numberOfLines = thing.length;
  				}
  			}
  		});
  		return numberOfLines;
  	};
  	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();
  	};
  	helpers.color = function(c) {
  		if (!color) {
  			console.error('Color.js not found!');
  			return c;
  		}
  
  		/* global CanvasGradient */
  		if (c instanceof CanvasGradient) {
  			return color(Chart.defaults.global.defaultColor);
  		}
  
  		return color(c);
  	};
  	helpers.addResizeListener = function(node, callback) {
  		var iframe = document.createElement('iframe');
  		iframe.className = 'chartjs-hidden-iframe';
  		iframe.style.cssText =
  			'display:block;'+
  			'overflow:hidden;'+
  			'border:0;'+
  			'margin:0;'+
  			'top:0;'+
  			'left:0;'+
  			'bottom:0;'+
  			'right:0;'+
  			'height:100%;'+
  			'width:100%;'+
  			'position:absolute;'+
  			'pointer-events:none;'+
  			'z-index:-1;';
  
  		// Prevent the iframe to gain focus on tab.
  		// https://github.com/chartjs/Chart.js/issues/3090
  		iframe.tabIndex = -1;
  
  		// Let's keep track of this added iframe and thus avoid DOM query when removing it.
  		var stub = node._chartjs = {
  			resizer: iframe,
  			ticking: false
  		};
  
  		// Throttle the callback notification until the next animation frame.
  		var notify = function() {
  			if (!stub.ticking) {
  				stub.ticking = true;
  				helpers.requestAnimFrame.call(window, function() {
  					if (stub.resizer) {
  						stub.ticking = false;
  						return callback();
  					}
  				});
  			}
  		};
  
  		// If the iframe is re-attached to the DOM, the resize listener is removed because the
  		// content is reloaded, so make sure to install the handler after the iframe is loaded.
  		// https://github.com/chartjs/Chart.js/issues/3521
  		helpers.addEvent(iframe, 'load', function() {
  			helpers.addEvent(iframe.contentWindow || iframe, 'resize', notify);
  
  			// The iframe size might have changed while loading, which can also
  			// happen if the size has been changed while detached from the DOM.
  			notify();
  		});
  
  		node.insertBefore(iframe, node.firstChild);
  	};
  	helpers.removeResizeListener = function(node) {
  		if (!node || !node._chartjs) {
  			return;
  		}
  
  		var iframe = node._chartjs.resizer;
  		if (iframe) {
  			iframe.parentNode.removeChild(iframe);
  			node._chartjs.resizer = null;
  		}
  
  		delete node._chartjs;
  	};
  	helpers.isArray = Array.isArray?
  		function(obj) {
  			return Array.isArray(obj);
  		} :
  		function(obj) {
  			return Object.prototype.toString.call(obj) === '[object Array]';
  		};
  	// ! @see http://stackoverflow.com/a/14853974
  	helpers.arrayEquals = function(a0, a1) {
  		var i, ilen, v0, v1;
  
  		if (!a0 || !a1 || a0.length !== a1.length) {
  			return false;
  		}
  
  		for (i = 0, ilen=a0.length; i < ilen; ++i) {
  			v0 = a0[i];
  			v1 = a1[i];
  
  			if (v0 instanceof Array && v1 instanceof Array) {
  				if (!helpers.arrayEquals(v0, v1)) {
  					return false;
  				}
  			} else if (v0 !== v1) {
  				// NOTE: two different object instances will never be equal: {x:20} != {x:20}
  				return false;
  			}
  		}
  
  		return true;
  	};
  	helpers.callCallback = function(fn, args, _tArg) {
  		if (fn && typeof fn.call === 'function') {
  			fn.apply(_tArg, args);
  		}
  	};
  	helpers.getHoverColor = function(colorValue) {
  		/* global CanvasPattern */
  		return (colorValue instanceof CanvasPattern) ?
  			colorValue :
  			helpers.color(colorValue).saturate(0.5).darken(0.1).rgbString();
  	};
  };
  