text: /**
   * Flot plugin that provides spline interpolation for line graphs
   * author: Alex Bardas < alex.bardas@gmail.com >
   * modified by: Avi Kohn https://github.com/AMKohn
   * based on the spline interpolation described at:
   *		 http://scaledinnovation.com/analytics/splines/aboutSplines.html
   *
   * Example usage: (add in plot options series object)
   *		for linespline:
   *			series: {
   *				...
   *				lines: {
   *					show: false
   *				},
   *				splines: {
   *					show: true,
   *					tension: x, (float between 0 and 1, defaults to 0.5),
   *					lineWidth: y (number, defaults to 2),
   *					fill: z (float between 0 .. 1 or false, as in flot documentation)
   *				},
   *				...
   *			}
   *		areaspline:
   *			series: {
   *				...
   *				lines: {
   *					show: true,
   *					lineWidth: 0, (line drawing will not execute)
   *					fill: x, (float between 0 .. 1, as in flot documentation)
   *					...
   *				},
   *				splines: {
   *					show: true,
   *					tension: 0.5 (float between 0 and 1)
   *				},
   *				...
   *			}
   *
   */
  
  (function($) {
  	'use strict'
  
  	/**
  	 * @param {Number} x0, y0, x1, y1: coordinates of the end (knot) points of the segment
  	 * @param {Number} x2, y2: the next knot (not connected, but needed to calculate p2)
  	 * @param {Number} tension: control how far the control points spread
  	 * @return {Array}: p1 -> control point, from x1 back toward x0
  	 * 					p2 -> the next control point, returned to become the next segment's p1
  	 *
  	 * @api private
  	 */
  	function getControlPoints(x0, y0, x1, y1, x2, y2, tension) {
  
  		var pow = Math.pow,
  			sqrt = Math.sqrt,
  			d01, d12, fa, fb, p1x, p1y, p2x, p2y;
  
  		//  Scaling factors: distances from this knot to the previous and following knots.
  		d01 = sqrt(pow(x1 - x0, 2) + pow(y1 - y0, 2));
  		d12 = sqrt(pow(x2 - x1, 2) + pow(y2 - y1, 2));
  
  		fa = tension * d01 / (d01 + d12);
  		fb = tension - fa;
  
  		p1x = x1 + fa * (x0 - x2);
  		p1y = y1 + fa * (y0 - y2);
  
  		p2x = x1 - fb * (x0 - x2);
  		p2y = y1 - fb * (y0 - y2);
  
  		return [p1x, p1y, p2x, p2y];
  	}
  
  	var line = [];
  
  	function drawLine(points, ctx, height, fill, seriesColor) {
  		var c = $.color.parse(seriesColor);
  
  		c.a = typeof fill == "number" ? fill : .3;
  		c.normalize();
  		c = c.toString();
  
  		ctx.beginPath();
  		ctx.moveTo(points[0][0], points[0][1]);
  
  		var plength = points.length;
  
  		for (var i = 0; i < plength; i++) {
  			ctx[points[i][3]].apply(ctx, points[i][2]);
  		}
  
  		ctx.stroke();
  
  		ctx.lineWidth = 0;
  		ctx.lineTo(points[plength - 1][0], height);
  		ctx.lineTo(points[0][0], height);
  
  		ctx.closePath();
  		
  		if (fill !== false) {
  			ctx.fillStyle = c;
  			ctx.fill();
  		}
  	}
  
  	/**
  	 * @param {Object} ctx: canvas context
  	 * @param {String} type: accepted strings: 'bezier' or 'quadratic' (defaults to quadratic)
  	 * @param {Array} points: 2 points for which to draw the interpolation
  	 * @param {Array} cpoints: control points for those segment points
  	 *
  	 * @api private
  	 */
  	function queue(ctx, type, points, cpoints) {
  		if (type === void 0 || (type !== 'bezier' && type !== 'quadratic')) {
  			type = 'quadratic';
  		}
  		type = type + 'CurveTo';
  
  		if (line.length == 0) line.push([points[0], points[1], cpoints.concat(points.slice(2)), type]);
  		else if (type == "quadraticCurveTo" && points.length == 2) {
  			cpoints = cpoints.slice(0, 2).concat(points);
  
  			line.push([points[0], points[1], cpoints, type]);
  		}
  		else line.push([points[2], points[3], cpoints.concat(points.slice(2)), type]);
  	}
  
  	/**
  	 * @param {Object} plot
  	 * @param {Object} ctx: canvas context
  	 * @param {Object} series
  	 *
  	 * @api private
  	 */
  
  	function drawSpline(plot, ctx, series) {
  		// Not interested if spline is not requested
  		if (series.splines.show !== true) {
  			return;
  		}
  
  		var cp = [],
  			// array of control points
  			tension = series.splines.tension || 0.5,
  			idx, x, y, points = series.datapoints.points,
  			ps = series.datapoints.pointsize,
  			plotOffset = plot.getPlotOffset(),
  			len = points.length,
  			pts = [];
  
  		line = [];
  
  		// Cannot display a linespline/areaspline if there are less than 3 points
  		if (len / ps < 4) {
  			$.extend(series.lines, series.splines);
  			return;
  		}
  
  		for (idx = 0; idx < len; idx += ps) {
  			x = points[idx];
  			y = points[idx + 1];
  			if (x == null || x < series.xaxis.min || x > series.xaxis.max || y < series.yaxis.min || y > series.yaxis.max) {
  				continue;
  			}
  
  			pts.push(series.xaxis.p2c(x) + plotOffset.left, series.yaxis.p2c(y) + plotOffset.top);
  		}
  
  		len = pts.length;
  
  		// Draw an open curve, not connected at the ends
  		for (idx = 0; idx < len - 2; idx += 2) {
  			cp = cp.concat(getControlPoints.apply(this, pts.slice(idx, idx + 6).concat([tension])));
  		}
  
  		ctx.save();
  		ctx.strokeStyle = series.color;
  		ctx.lineWidth = series.splines.lineWidth;
  
  		queue(ctx, 'quadratic', pts.slice(0, 4), cp.slice(0, 2));
  
  		for (idx = 2; idx < len - 3; idx += 2) {
  			queue(ctx, 'bezier', pts.slice(idx, idx + 4), cp.slice(2 * idx - 2, 2 * idx + 2));
  		}
  
  		queue(ctx, 'quadratic', pts.slice(len - 2, len), [cp[2 * len - 10], cp[2 * len - 9], pts[len - 4], pts[len - 3]]);
  
  		drawLine(line, ctx, plot.height() + 10, series.splines.fill, series.color);
  
  		ctx.restore();
  	}
  
  	$.plot.plugins.push({
  		init: function(plot) {
  			plot.hooks.drawSeries.push(drawSpline);
  		},
  		options: {
  			series: {
  				splines: {
  					show: false,
  					lineWidth: 2,
  					tension: 0.5,
  					fill: false
  				}
  			}
  		},
  		name: 'spline',
  		version: '0.8.2'
  	});
  })(jQuery);