core.tooltip.js

'use strict';

var defaults = require('./core.defaults');
var Element = require('./core.element');
var helpers = require('../helpers/index');

var valueOrDefault = helpers.valueOrDefault;
var getRtlHelper = helpers.rtl.getRtlAdapter;

defaults._set('global', {
	tooltips: {
		enabled: true,
		custom: null,
		mode: 'nearest',
		position: 'average',
		intersect: true,
		backgroundColor: 'rgba(0,0,0,0.8)',
		titleFontStyle: 'bold',
		titleSpacing: 2,
		titleMarginBottom: 6,
		titleFontColor: '#fff',
		titleAlign: 'left',
		bodySpacing: 2,
		bodyFontColor: '#fff',
		bodyAlign: 'left',
		footerFontStyle: 'bold',
		footerSpacing: 2,
		footerMarginTop: 6,
		footerFontColor: '#fff',
		footerAlign: 'left',
		yPadding: 6,
		xPadding: 6,
		caretPadding: 2,
		caretSize: 5,
		cornerRadius: 6,
		multiKeyBackground: '#fff',
		displayColors: true,
		borderColor: 'rgba(0,0,0,0)',
		borderWidth: 0,
		callbacks: {
			// Args are: (tooltipItems, data)
			beforeTitle: helpers.noop,
			title: function(tooltipItems, data) {
				var title = '';
				var labels = data.labels;
				var labelCount = labels ? labels.length : 0;

				if (tooltipItems.length > 0) {
					var item = tooltipItems[0];
					if (item.label) {
						title = item.label;
					} else if (item.xLabel) {
						title = item.xLabel;
					} else if (labelCount > 0 && item.index < labelCount) {
						title = labels[item.index];
					}
				}

				return title;
			},
			afterTitle: helpers.noop,

			// Args are: (tooltipItems, data)
			beforeBody: helpers.noop,

			// Args are: (tooltipItem, data)
			beforeLabel: helpers.noop,
			label: function(tooltipItem, data) {
				var label = data.datasets[tooltipItem.datasetIndex].label || '';

				if (label) {
					label += ': ';
				}
				if (!helpers.isNullOrUndef(tooltipItem.value)) {
					label += tooltipItem.value;
				} else {
					label += tooltipItem.yLabel;
				}
				return label;
			},
			labelColor: function(tooltipItem, chart) {
				var meta = chart.getDatasetMeta(tooltipItem.datasetIndex);
				var activeElement = meta.data[tooltipItem.index];
				var view = activeElement._view;
				return {
					borderColor: view.borderColor,
					backgroundColor: view.backgroundColor
				};
			},
			labelTextColor: function() {
				return this._options.bodyFontColor;
			},
			afterLabel: helpers.noop,

			// Args are: (tooltipItems, data)
			afterBody: helpers.noop,

			// Args are: (tooltipItems, data)
			beforeFooter: helpers.noop,
			footer: helpers.noop,
			afterFooter: helpers.noop
		}
	}
});

var positioners = {
	/**
	 * Average mode places the tooltip at the average position of the elements shown
	 * @function Chart.Tooltip.positioners.average
	 * @param elements {ChartElement[]} the elements being displayed in the tooltip
	 * @returns {object} tooltip position
	 */
	average: function(elements) {
		if (!elements.length) {
			return false;
		}

		var i, len;
		var x = 0;
		var y = 0;
		var count = 0;

		for (i = 0, len = elements.length; i < len; ++i) {
			var el = elements[i];
			if (el && el.hasValue()) {
				var pos = el.tooltipPosition();
				x += pos.x;
				y += pos.y;
				++count;
			}
		}

		return {
			x: x / count,
			y: y / count
		};
	},

	/**
	 * Gets the tooltip position nearest of the item nearest to the event position
	 * @function Chart.Tooltip.positioners.nearest
	 * @param elements {Chart.Element[]} the tooltip elements
	 * @param eventPosition {object} the position of the event in canvas coordinates
	 * @returns {object} the tooltip position
	 */
	nearest: function(elements, eventPosition) {
		var x = eventPosition.x;
		var y = eventPosition.y;
		var minDistance = Number.POSITIVE_INFINITY;
		var i, len, nearestElement;

		for (i = 0, len = elements.length; i < len; ++i) {
			var el = elements[i];
			if (el && el.hasValue()) {
				var center = el.getCenterPoint();
				var d = helpers.distanceBetweenPoints(eventPosition, center);

				if (d < minDistance) {
					minDistance = d;
					nearestElement = el;
				}
			}
		}

		if (nearestElement) {
			var tp = nearestElement.tooltipPosition();
			x = tp.x;
			y = tp.y;
		}

		return {
			x: x,
			y: y
		};
	}
};

// Helper to push or concat based on if the 2nd parameter is an array or not
function pushOrConcat(base, toPush) {
	if (toPush) {
		if (helpers.isArray(toPush)) {
			// base = base.concat(toPush);
			Array.prototype.push.apply(base, toPush);
		} else {
			base.push(toPush);
		}
	}

	return base;
}

/**
 * Returns array of strings split by newline
 * @param {string} value - The value to split by newline.
 * @returns {string[]} value if newline present - Returned from String split() method
 * @function
 */
function splitNewlines(str) {
	if ((typeof str === 'string' || str instanceof String) && str.indexOf('\n') > -1) {
		return str.split('\n');
	}
	return str;
}


/**
 * Private helper to create a tooltip item model
 * @param element - the chart element (point, arc, bar) to create the tooltip item for
 * @return new tooltip item
 */
function createTooltipItem(element) {
	var xScale = element._xScale;
	var yScale = element._yScale || element._scale; // handle radar || polarArea charts
	var index = element._index;
	var datasetIndex = element._datasetIndex;
	var controller = element._chart.getDatasetMeta(datasetIndex).controller;
	var indexScale = controller._getIndexScale();
	var valueScale = controller._getValueScale();

	return {
		xLabel: xScale ? xScale.getLabelForIndex(index, datasetIndex) : '',
		yLabel: yScale ? yScale.getLabelForIndex(index, datasetIndex) : '',
		label: indexScale ? '' + indexScale.getLabelForIndex(index, datasetIndex) : '',
		value: valueScale ? '' + valueScale.getLabelForIndex(index, datasetIndex) : '',
		index: index,
		datasetIndex: datasetIndex,
		x: element._model.x,
		y: element._model.y
	};
}

/**
 * Helper to get the reset model for the tooltip
 * @param tooltipOpts {object} the tooltip options
 */
function getBaseModel(tooltipOpts) {
	var globalDefaults = defaults.global;

	return {
		// Positioning
		xPadding: tooltipOpts.xPadding,
		yPadding: tooltipOpts.yPadding,
		xAlign: tooltipOpts.xAlign,
		yAlign: tooltipOpts.yAlign,

		// Drawing direction and text direction
		rtl: tooltipOpts.rtl,
		textDirection: tooltipOpts.textDirection,

		// Body
		bodyFontColor: tooltipOpts.bodyFontColor,
		_bodyFontFamily: valueOrDefault(tooltipOpts.bodyFontFamily, globalDefaults.defaultFontFamily),
		_bodyFontStyle: valueOrDefault(tooltipOpts.bodyFontStyle, globalDefaults.defaultFontStyle),
		_bodyAlign: tooltipOpts.bodyAlign,
		bodyFontSize: valueOrDefault(tooltipOpts.bodyFontSize, globalDefaults.defaultFontSize),
		bodySpacing: tooltipOpts.bodySpacing,

		// Title
		titleFontColor: tooltipOpts.titleFontColor,
		_titleFontFamily: valueOrDefault(tooltipOpts.titleFontFamily, globalDefaults.defaultFontFamily),
		_titleFontStyle: valueOrDefault(tooltipOpts.titleFontStyle, globalDefaults.defaultFontStyle),
		titleFontSize: valueOrDefault(tooltipOpts.titleFontSize, globalDefaults.defaultFontSize),
		_titleAlign: tooltipOpts.titleAlign,
		titleSpacing: tooltipOpts.titleSpacing,
		titleMarginBottom: tooltipOpts.titleMarginBottom,

		// Footer
		footerFontColor: tooltipOpts.footerFontColor,
		_footerFontFamily: valueOrDefault(tooltipOpts.footerFontFamily, globalDefaults.defaultFontFamily),
		_footerFontStyle: valueOrDefault(tooltipOpts.footerFontStyle, globalDefaults.defaultFontStyle),
		footerFontSize: valueOrDefault(tooltipOpts.footerFontSize, globalDefaults.defaultFontSize),
		_footerAlign: tooltipOpts.footerAlign,
		footerSpacing: tooltipOpts.footerSpacing,
		footerMarginTop: tooltipOpts.footerMarginTop,

		// Appearance
		caretSize: tooltipOpts.caretSize,
		cornerRadius: tooltipOpts.cornerRadius,
		backgroundColor: tooltipOpts.backgroundColor,
		opacity: 0,
		legendColorBackground: tooltipOpts.multiKeyBackground,
		displayColors: tooltipOpts.displayColors,
		borderColor: tooltipOpts.borderColor,
		borderWidth: tooltipOpts.borderWidth
	};
}

/**
 * Get the size of the tooltip
 */
function getTooltipSize(tooltip, model) {
	var ctx = tooltip._chart.ctx;

	var height = model.yPadding * 2; // Tooltip Padding
	var width = 0;

	// Count of all lines in the body
	var body = model.body;
	var combinedBodyLength = body.reduce(function(count, bodyItem) {
		return count + bodyItem.before.length + bodyItem.lines.length + bodyItem.after.length;
	}, 0);
	combinedBodyLength += model.beforeBody.length + model.afterBody.length;

	var titleLineCount = model.title.length;
	var footerLineCount = model.footer.length;
	var titleFontSize = model.titleFontSize;
	var bodyFontSize = model.bodyFontSize;
	var footerFontSize = model.footerFontSize;

	height += titleLineCount * titleFontSize; // Title Lines
	height += titleLineCount ? (titleLineCount - 1) * model.titleSpacing : 0; // Title Line Spacing
	height += titleLineCount ? model.titleMarginBottom : 0; // Title's bottom Margin
	height += combinedBodyLength * bodyFontSize; // Body Lines
	height += combinedBodyLength ? (combinedBodyLength - 1) * model.bodySpacing : 0; // Body Line Spacing
	height += footerLineCount ? model.footerMarginTop : 0; // Footer Margin
	height += footerLineCount * (footerFontSize); // Footer Lines
	height += footerLineCount ? (footerLineCount - 1) * model.footerSpacing : 0; // Footer Line Spacing

	// Title width
	var widthPadding = 0;
	var maxLineWidth = function(line) {
		width = Math.max(width, ctx.measureText(line).width + widthPadding);
	};

	ctx.font = helpers.fontString(titleFontSize, model._titleFontStyle, model._titleFontFamily);
	helpers.each(model.title, maxLineWidth);

	// Body width
	ctx.font = helpers.fontString(bodyFontSize, model._bodyFontStyle, model._bodyFontFamily);
	helpers.each(model.beforeBody.concat(model.afterBody), maxLineWidth);

	// Body lines may include some extra width due to the color box
	widthPadding = model.displayColors ? (bodyFontSize + 2) : 0;
	helpers.each(body, function(bodyItem) {
		helpers.each(bodyItem.before, maxLineWidth);
		helpers.each(bodyItem.lines, maxLineWidth);
		helpers.each(bodyItem.after, maxLineWidth);
	});

	// Reset back to 0
	widthPadding = 0;

	// Footer width
	ctx.font = helpers.fontString(footerFontSize, model._footerFontStyle, model._footerFontFamily);
	helpers.each(model.footer, maxLineWidth);

	// Add padding
	width += 2 * model.xPadding;

	return {
		width: width,
		height: height
	};
}

/**
 * Helper to get the alignment of a tooltip given the size
 */
function determineAlignment(tooltip, size) {
	var model = tooltip._model;
	var chart = tooltip._chart;
	var chartArea = tooltip._chart.chartArea;
	var xAlign = 'center';
	var yAlign = 'center';

	if (model.y < size.height) {
		yAlign = 'top';
	} else if (model.y > (chart.height - size.height)) {
		yAlign = 'bottom';
	}

	var lf, rf; // functions to determine left, right alignment
	var olf, orf; // functions to determine if left/right alignment causes tooltip to go outside chart
	var yf; // function to get the y alignment if the tooltip goes outside of the left or right edges
	var midX = (chartArea.left + chartArea.right) / 2;
	var midY = (chartArea.top + chartArea.bottom) / 2;

	if (yAlign === 'center') {
		lf = function(x) {
			return x <= midX;
		};
		rf = function(x) {
			return x > midX;
		};
	} else {
		lf = function(x) {
			return x <= (size.width / 2);
		};
		rf = function(x) {
			return x >= (chart.width - (size.width / 2));
		};
	}

	olf = function(x) {
		return x + size.width + model.caretSize + model.caretPadding > chart.width;
	};
	orf = function(x) {
		return x - size.width - model.caretSize - model.caretPadding < 0;
	};
	yf = function(y) {
		return y <= midY ? 'top' : 'bottom';
	};

	if (lf(model.x)) {
		xAlign = 'left';

		// Is tooltip too wide and goes over the right side of the chart.?
		if (olf(model.x)) {
			xAlign = 'center';
			yAlign = yf(model.y);
		}
	} else if (rf(model.x)) {
		xAlign = 'right';

		// Is tooltip too wide and goes outside left edge of canvas?
		if (orf(model.x)) {
			xAlign = 'center';
			yAlign = yf(model.y);
		}
	}

	var opts = tooltip._options;
	return {
		xAlign: opts.xAlign ? opts.xAlign : xAlign,
		yAlign: opts.yAlign ? opts.yAlign : yAlign
	};
}

/**
 * Helper to get the location a tooltip needs to be placed at given the initial position (via the vm) and the size and alignment
 */
function getBackgroundPoint(vm, size, alignment, chart) {
	// Background Position
	var x = vm.x;
	var y = vm.y;

	var caretSize = vm.caretSize;
	var caretPadding = vm.caretPadding;
	var cornerRadius = vm.cornerRadius;
	var xAlign = alignment.xAlign;
	var yAlign = alignment.yAlign;
	var paddingAndSize = caretSize + caretPadding;
	var radiusAndPadding = cornerRadius + caretPadding;

	if (xAlign === 'right') {
		x -= size.width;
	} else if (xAlign === 'center') {
		x -= (size.width / 2);
		if (x + size.width > chart.width) {
			x = chart.width - size.width;
		}
		if (x < 0) {
			x = 0;
		}
	}

	if (yAlign === 'top') {
		y += paddingAndSize;
	} else if (yAlign === 'bottom') {
		y -= size.height + paddingAndSize;
	} else {
		y -= (size.height / 2);
	}

	if (yAlign === 'center') {
		if (xAlign === 'left') {
			x += paddingAndSize;
		} else if (xAlign === 'right') {
			x -= paddingAndSize;
		}
	} else if (xAlign === 'left') {
		x -= radiusAndPadding;
	} else if (xAlign === 'right') {
		x += radiusAndPadding;
	}

	return {
		x: x,
		y: y
	};
}

function getAlignedX(vm, align) {
	return align === 'center'
		? vm.x + vm.width / 2
		: align === 'right'
			? vm.x + vm.width - vm.xPadding
			: vm.x + vm.xPadding;
}

/**
 * Helper to build before and after body lines
 */
function getBeforeAfterBodyLines(callback) {
	return pushOrConcat([], splitNewlines(callback));
}

var exports = Element.extend({
	initialize: function() {
		this._model = getBaseModel(this._options);
		this._lastActive = [];
	},

	// Get the title
	// Args are: (tooltipItem, data)
	getTitle: function() {
		var me = this;
		var opts = me._options;
		var callbacks = opts.callbacks;

		var beforeTitle = callbacks.beforeTitle.apply(me, arguments);
		var title = callbacks.title.apply(me, arguments);
		var afterTitle = callbacks.afterTitle.apply(me, arguments);

		var lines = [];
		lines = pushOrConcat(lines, splitNewlines(beforeTitle));
		lines = pushOrConcat(lines, splitNewlines(title));
		lines = pushOrConcat(lines, splitNewlines(afterTitle));

		return lines;
	},

	// Args are: (tooltipItem, data)
	getBeforeBody: function() {
		return getBeforeAfterBodyLines(this._options.callbacks.beforeBody.apply(this, arguments));
	},

	// Args are: (tooltipItem, data)
	getBody: function(tooltipItems, data) {
		var me = this;
		var callbacks = me._options.callbacks;
		var bodyItems = [];

		helpers.each(tooltipItems, function(tooltipItem) {
			var bodyItem = {
				before: [],
				lines: [],
				after: []
			};
			pushOrConcat(bodyItem.before, splitNewlines(callbacks.beforeLabel.call(me, tooltipItem, data)));
			pushOrConcat(bodyItem.lines, callbacks.label.call(me, tooltipItem, data));
			pushOrConcat(bodyItem.after, splitNewlines(callbacks.afterLabel.call(me, tooltipItem, data)));

			bodyItems.push(bodyItem);
		});

		return bodyItems;
	},

	// Args are: (tooltipItem, data)
	getAfterBody: function() {
		return getBeforeAfterBodyLines(this._options.callbacks.afterBody.apply(this, arguments));
	},

	// Get the footer and beforeFooter and afterFooter lines
	// Args are: (tooltipItem, data)
	getFooter: function() {
		var me = this;
		var callbacks = me._options.callbacks;

		var beforeFooter = callbacks.beforeFooter.apply(me, arguments);
		var footer = callbacks.footer.apply(me, arguments);
		var afterFooter = callbacks.afterFooter.apply(me, arguments);

		var lines = [];
		lines = pushOrConcat(lines, splitNewlines(beforeFooter));
		lines = pushOrConcat(lines, splitNewlines(footer));
		lines = pushOrConcat(lines, splitNewlines(afterFooter));

		return lines;
	},

	update: function(changed) {
		var me = this;
		var opts = me._options;

		// Need to regenerate the model because its faster than using extend and it is necessary due to the optimization in Chart.Element.transition
		// that does _view = _model if ease === 1. This causes the 2nd tooltip update to set properties in both the view and model at the same time
		// which breaks any animations.
		var existingModel = me._model;
		var model = me._model = getBaseModel(opts);
		var active = me._active;

		var data = me._data;

		// In the case where active.length === 0 we need to keep these at existing values for good animations
		var alignment = {
			xAlign: existingModel.xAlign,
			yAlign: existingModel.yAlign
		};
		var backgroundPoint = {
			x: existingModel.x,
			y: existingModel.y
		};
		var tooltipSize = {
			width: existingModel.width,
			height: existingModel.height
		};
		var tooltipPosition = {
			x: existingModel.caretX,
			y: existingModel.caretY
		};

		var i, len;

		if (active.length) {
			model.opacity = 1;

			var labelColors = [];
			var labelTextColors = [];
			tooltipPosition = positioners[opts.position].call(me, active, me._eventPosition);

			var tooltipItems = [];
			for (i = 0, len = active.length; i < len; ++i) {
				tooltipItems.push(createTooltipItem(active[i]));
			}

			// If the user provided a filter function, use it to modify the tooltip items
			if (opts.filter) {
				tooltipItems = tooltipItems.filter(function(a) {
					return opts.filter(a, data);
				});
			}

			// If the user provided a sorting function, use it to modify the tooltip items
			if (opts.itemSort) {
				tooltipItems = tooltipItems.sort(function(a, b) {
					return opts.itemSort(a, b, data);
				});
			}

			// Determine colors for boxes
			helpers.each(tooltipItems, function(tooltipItem) {
				labelColors.push(opts.callbacks.labelColor.call(me, tooltipItem, me._chart));
				labelTextColors.push(opts.callbacks.labelTextColor.call(me, tooltipItem, me._chart));
			});


			// Build the Text Lines
			model.title = me.getTitle(tooltipItems, data);
			model.beforeBody = me.getBeforeBody(tooltipItems, data);
			model.body = me.getBody(tooltipItems, data);
			model.afterBody = me.getAfterBody(tooltipItems, data);
			model.footer = me.getFooter(tooltipItems, data);

			// Initial positioning and colors
			model.x = tooltipPosition.x;
			model.y = tooltipPosition.y;
			model.caretPadding = opts.caretPadding;
			model.labelColors = labelColors;
			model.labelTextColors = labelTextColors;

			// data points
			model.dataPoints = tooltipItems;

			// We need to determine alignment of the tooltip
			tooltipSize = getTooltipSize(this, model);
			alignment = determineAlignment(this, tooltipSize);
			// Final Size and Position
			backgroundPoint = getBackgroundPoint(model, tooltipSize, alignment, me._chart);
		} else {
			model.opacity = 0;
		}

		model.xAlign = alignment.xAlign;
		model.yAlign = alignment.yAlign;
		model.x = backgroundPoint.x;
		model.y = backgroundPoint.y;
		model.width = tooltipSize.width;
		model.height = tooltipSize.height;

		// Point where the caret on the tooltip points to
		model.caretX = tooltipPosition.x;
		model.caretY = tooltipPosition.y;

		me._model = model;

		if (changed && opts.custom) {
			opts.custom.call(me, model);
		}

		return me;
	},

	drawCaret: function(tooltipPoint, size) {
		var ctx = this._chart.ctx;
		var vm = this._view;
		var caretPosition = this.getCaretPosition(tooltipPoint, size, vm);

		ctx.lineTo(caretPosition.x1, caretPosition.y1);
		ctx.lineTo(caretPosition.x2, caretPosition.y2);
		ctx.lineTo(caretPosition.x3, caretPosition.y3);
	},
	getCaretPosition: function(tooltipPoint, size, vm) {
		var x1, x2, x3, y1, y2, y3;
		var caretSize = vm.caretSize;
		var cornerRadius = vm.cornerRadius;
		var xAlign = vm.xAlign;
		var yAlign = vm.yAlign;
		var ptX = tooltipPoint.x;
		var ptY = tooltipPoint.y;
		var width = size.width;
		var height = size.height;

		if (yAlign === 'center') {
			y2 = ptY + (height / 2);

			if (xAlign === 'left') {
				x1 = ptX;
				x2 = x1 - caretSize;
				x3 = x1;

				y1 = y2 + caretSize;
				y3 = y2 - caretSize;
			} else {
				x1 = ptX + width;
				x2 = x1 + caretSize;
				x3 = x1;

				y1 = y2 - caretSize;
				y3 = y2 + caretSize;
			}
		} else {
			if (xAlign === 'left') {
				x2 = ptX + cornerRadius + (caretSize);
				x1 = x2 - caretSize;
				x3 = x2 + caretSize;
			} else if (xAlign === 'right') {
				x2 = ptX + width - cornerRadius - caretSize;
				x1 = x2 - caretSize;
				x3 = x2 + caretSize;
			} else {
				x2 = vm.caretX;
				x1 = x2 - caretSize;
				x3 = x2 + caretSize;
			}
			if (yAlign === 'top') {
				y1 = ptY;
				y2 = y1 - caretSize;
				y3 = y1;
			} else {
				y1 = ptY + height;
				y2 = y1 + caretSize;
				y3 = y1;
				// invert drawing order
				var tmp = x3;
				x3 = x1;
				x1 = tmp;
			}
		}
		return {x1: x1, x2: x2, x3: x3, y1: y1, y2: y2, y3: y3};
	},

	drawTitle: function(pt, vm, ctx) {
		var title = vm.title;
		var length = title.length;
		var titleFontSize, titleSpacing, i;

		if (length) {
			var rtlHelper = getRtlHelper(vm.rtl, vm.x, vm.width);

			pt.x = getAlignedX(vm, vm._titleAlign);

			ctx.textAlign = rtlHelper.textAlign(vm._titleAlign);
			ctx.textBaseline = 'middle';

			titleFontSize = vm.titleFontSize;
			titleSpacing = vm.titleSpacing;

			ctx.fillStyle = vm.titleFontColor;
			ctx.font = helpers.fontString(titleFontSize, vm._titleFontStyle, vm._titleFontFamily);

			for (i = 0; i < length; ++i) {
				ctx.fillText(title[i], rtlHelper.x(pt.x), pt.y + titleFontSize / 2);
				pt.y += titleFontSize + titleSpacing; // Line Height and spacing

				if (i + 1 === length) {
					pt.y += vm.titleMarginBottom - titleSpacing; // If Last, add margin, remove spacing
				}
			}
		}
	},

	drawBody: function(pt, vm, ctx) {
		var bodyFontSize = vm.bodyFontSize;
		var bodySpacing = vm.bodySpacing;
		var bodyAlign = vm._bodyAlign;
		var body = vm.body;
		var drawColorBoxes = vm.displayColors;
		var xLinePadding = 0;
		var colorX = drawColorBoxes ? getAlignedX(vm, 'left') : 0;

		var rtlHelper = getRtlHelper(vm.rtl, vm.x, vm.width);

		var fillLineOfText = function(line) {
			ctx.fillText(line, rtlHelper.x(pt.x + xLinePadding), pt.y + bodyFontSize / 2);
			pt.y += bodyFontSize + bodySpacing;
		};

		var bodyItem, textColor, labelColors, lines, i, j, ilen, jlen;
		var bodyAlignForCalculation = rtlHelper.textAlign(bodyAlign);

		ctx.textAlign = bodyAlign;
		ctx.textBaseline = 'middle';
		ctx.font = helpers.fontString(bodyFontSize, vm._bodyFontStyle, vm._bodyFontFamily);

		pt.x = getAlignedX(vm, bodyAlignForCalculation);

		// Before body lines
		ctx.fillStyle = vm.bodyFontColor;
		helpers.each(vm.beforeBody, fillLineOfText);

		xLinePadding = drawColorBoxes && bodyAlignForCalculation !== 'right'
			? bodyAlign === 'center' ? (bodyFontSize / 2 + 1) : (bodyFontSize + 2)
			: 0;

		// Draw body lines now
		for (i = 0, ilen = body.length; i < ilen; ++i) {
			bodyItem = body[i];
			textColor = vm.labelTextColors[i];
			labelColors = vm.labelColors[i];

			ctx.fillStyle = textColor;
			helpers.each(bodyItem.before, fillLineOfText);

			lines = bodyItem.lines;
			for (j = 0, jlen = lines.length; j < jlen; ++j) {
				// Draw Legend-like boxes if needed
				if (drawColorBoxes) {
					var rtlColorX = rtlHelper.x(colorX);

					// Fill a white rect so that colours merge nicely if the opacity is < 1
					ctx.fillStyle = vm.legendColorBackground;
					ctx.fillRect(rtlHelper.leftForLtr(rtlColorX, bodyFontSize), pt.y, bodyFontSize, bodyFontSize);

					// Border
					ctx.lineWidth = 1;
					ctx.strokeStyle = labelColors.borderColor;
					ctx.strokeRect(rtlHelper.leftForLtr(rtlColorX, bodyFontSize), pt.y, bodyFontSize, bodyFontSize);

					// Inner square
					ctx.fillStyle = labelColors.backgroundColor;
					ctx.fillRect(rtlHelper.leftForLtr(rtlHelper.xPlus(rtlColorX, 1), bodyFontSize - 2), pt.y + 1, bodyFontSize - 2, bodyFontSize - 2);
					ctx.fillStyle = textColor;
				}

				fillLineOfText(lines[j]);
			}

			helpers.each(bodyItem.after, fillLineOfText);
		}

		// Reset back to 0 for after body
		xLinePadding = 0;

		// After body lines
		helpers.each(vm.afterBody, fillLineOfText);
		pt.y -= bodySpacing; // Remove last body spacing
	},

	drawFooter: function(pt, vm, ctx) {
		var footer = vm.footer;
		var length = footer.length;
		var footerFontSize, i;

		if (length) {
			var rtlHelper = getRtlHelper(vm.rtl, vm.x, vm.width);

			pt.x = getAlignedX(vm, vm._footerAlign);
			pt.y += vm.footerMarginTop;

			ctx.textAlign = rtlHelper.textAlign(vm._footerAlign);
			ctx.textBaseline = 'middle';

			footerFontSize = vm.footerFontSize;

			ctx.fillStyle = vm.footerFontColor;
			ctx.font = helpers.fontString(footerFontSize, vm._footerFontStyle, vm._footerFontFamily);

			for (i = 0; i < length; ++i) {
				ctx.fillText(footer[i], rtlHelper.x(pt.x), pt.y + footerFontSize / 2);
				pt.y += footerFontSize + vm.footerSpacing;
			}
		}
	},

	drawBackground: function(pt, vm, ctx, tooltipSize) {
		ctx.fillStyle = vm.backgroundColor;
		ctx.strokeStyle = vm.borderColor;
		ctx.lineWidth = vm.borderWidth;
		var xAlign = vm.xAlign;
		var yAlign = vm.yAlign;
		var x = pt.x;
		var y = pt.y;
		var width = tooltipSize.width;
		var height = tooltipSize.height;
		var radius = vm.cornerRadius;

		ctx.beginPath();
		ctx.moveTo(x + radius, y);
		if (yAlign === 'top') {
			this.drawCaret(pt, tooltipSize);
		}
		ctx.lineTo(x + width - radius, y);
		ctx.quadraticCurveTo(x + width, y, x + width, y + radius);
		if (yAlign === 'center' && xAlign === 'right') {
			this.drawCaret(pt, tooltipSize);
		}
		ctx.lineTo(x + width, y + height - radius);
		ctx.quadraticCurveTo(x + width, y + height, x + width - radius, y + height);
		if (yAlign === 'bottom') {
			this.drawCaret(pt, tooltipSize);
		}
		ctx.lineTo(x + radius, y + height);
		ctx.quadraticCurveTo(x, y + height, x, y + height - radius);
		if (yAlign === 'center' && xAlign === 'left') {
			this.drawCaret(pt, tooltipSize);
		}
		ctx.lineTo(x, y + radius);
		ctx.quadraticCurveTo(x, y, x + radius, y);
		ctx.closePath();

		ctx.fill();

		if (vm.borderWidth > 0) {
			ctx.stroke();
		}
	},

	draw: function() {
		var ctx = this._chart.ctx;
		var vm = this._view;

		if (vm.opacity === 0) {
			return;
		}

		var tooltipSize = {
			width: vm.width,
			height: vm.height
		};
		var pt = {
			x: vm.x,
			y: vm.y
		};

		// IE11/Edge does not like very small opacities, so snap to 0
		var opacity = Math.abs(vm.opacity < 1e-3) ? 0 : vm.opacity;

		// Truthy/falsey value for empty tooltip
		var hasTooltipContent = vm.title.length || vm.beforeBody.length || vm.body.length || vm.afterBody.length || vm.footer.length;

		if (this._options.enabled && hasTooltipContent) {
			ctx.save();
			ctx.globalAlpha = opacity;

			// Draw Background
			this.drawBackground(pt, vm, ctx, tooltipSize);

			// Draw Title, Body, and Footer
			pt.y += vm.yPadding;

			helpers.rtl.overrideTextDirection(ctx, vm.textDirection);

			// Titles
			this.drawTitle(pt, vm, ctx);

			// Body
			this.drawBody(pt, vm, ctx);

			// Footer
			this.drawFooter(pt, vm, ctx);

			helpers.rtl.restoreTextDirection(ctx, vm.textDirection);

			ctx.restore();
		}
	},

	/**
	 * Handle an event
	 * @private
	 * @param {IEvent} event - The event to handle
	 * @returns {boolean} true if the tooltip changed
	 */
	handleEvent: function(e) {
		var me = this;
		var options = me._options;
		var changed = false;

		me._lastActive = me._lastActive || [];

		// Find Active Elements for tooltips
		if (e.type === 'mouseout') {
			me._active = [];
		} else {
			me._active = me._chart.getElementsAtEventForMode(e, options.mode, options);
			if (options.reverse) {
				me._active.reverse();
			}
		}

		// Remember Last Actives
		changed = !helpers.arrayEquals(me._active, me._lastActive);

		// Only handle target event on tooltip change
		if (changed) {
			me._lastActive = me._active;

			if (options.enabled || options.custom) {
				me._eventPosition = {
					x: e.x,
					y: e.y
				};

				me.update(true);
				me.pivot();
			}
		}

		return changed;
	}
});

/**
 * @namespace Chart.Tooltip.positioners
 */
exports.positioners = positioners;

module.exports = exports;