/* Flot plugin for plotting error bars.



Copyright (c) 2007-2013 IOLA and Ole Laursen.

Licensed under the MIT license.



Error bars are used to show standard deviation and other statistical

properties in a plot.



* Created by Rui Pereira  -  rui (dot) pereira (at) gmail (dot) com



This plugin allows you to plot error-bars over points. Set "errorbars" inside

the points series to the axis name over which there will be error values in

your data array (*even* if you do not intend to plot them later, by setting

"show: null" on xerr/yerr).



The plugin supports these options:



	series: {

		points: {

			errorbars: "x" or "y" or "xy",

			xerr: {

				show: null/false or true,

				asymmetric: null/false or true,

				upperCap: null or "-" or function,

				lowerCap: null or "-" or function,

				color: null or color,

				radius: null or number

			},

			yerr: { same options as xerr }

		}

	}



Each data point array is expected to be of the type:



	"x"  [ x, y, xerr ]

	"y"  [ x, y, yerr ]

	"xy" [ x, y, xerr, yerr ]



Where xerr becomes xerr_lower,xerr_upper for the asymmetric error case, and

equivalently for yerr. Eg., a datapoint for the "xy" case with symmetric

error-bars on X and asymmetric on Y would be:



	[ x, y, xerr, yerr_lower, yerr_upper ]



By default no end caps are drawn. Setting upperCap and/or lowerCap to "-" will

draw a small cap perpendicular to the error bar. They can also be set to a

user-defined drawing function, with (ctx, x, y, radius) as parameters, as eg.



	function drawSemiCircle( ctx, x, y, radius ) {

		ctx.beginPath();

		ctx.arc( x, y, radius, 0, Math.PI, false );

		ctx.moveTo( x - radius, y );

		ctx.lineTo( x + radius, y );

		ctx.stroke();

	}



Color and radius both default to the same ones of the points series if not

set. The independent radius parameter on xerr/yerr is useful for the case when

we may want to add error-bars to a line, without showing the interconnecting

points (with radius: 0), and still showing end caps on the error-bars.

shadowSize and lineWidth are derived as well from the points series.



*/



(function ($) {

    var options = {

        series: {

            points: {

                errorbars: null, //should be 'x', 'y' or 'xy'

                xerr: { err: 'x', show: null, asymmetric: null, upperCap: null, lowerCap: null, color: null, radius: null},

                yerr: { err: 'y', show: null, asymmetric: null, upperCap: null, lowerCap: null, color: null, radius: null}

            }

        }

    };



    function processRawData(plot, series, data, datapoints){

        if (!series.points.errorbars)

            return;



        // x,y values

        var format = [

            { x: true, number: true, required: true },

            { y: true, number: true, required: true }

        ];



        var errors = series.points.errorbars;

        // error bars - first X then Y

        if (errors == 'x' || errors == 'xy') {

            // lower / upper error

            if (series.points.xerr.asymmetric) {

                format.push({ x: true, number: true, required: true });

                format.push({ x: true, number: true, required: true });

            } else

                format.push({ x: true, number: true, required: true });

        }

        if (errors == 'y' || errors == 'xy') {

            // lower / upper error

            if (series.points.yerr.asymmetric) {

                format.push({ y: true, number: true, required: true });

                format.push({ y: true, number: true, required: true });

            } else

                format.push({ y: true, number: true, required: true });

        }

        datapoints.format = format;

    }



    function parseErrors(series, i){



        var points = series.datapoints.points;



        // read errors from points array

        var exl = null,

                exu = null,

                eyl = null,

                eyu = null;

        var xerr = series.points.xerr,

                yerr = series.points.yerr;



        var eb = series.points.errorbars;

        // error bars - first X

        if (eb == 'x' || eb == 'xy') {

            if (xerr.asymmetric) {

                exl = points[i + 2];

                exu = points[i + 3];

                if (eb == 'xy')

                    if (yerr.asymmetric){

                        eyl = points[i + 4];

                        eyu = points[i + 5];

                    } else eyl = points[i + 4];

            } else {

                exl = points[i + 2];

                if (eb == 'xy')

                    if (yerr.asymmetric) {

                        eyl = points[i + 3];

                        eyu = points[i + 4];

                    } else eyl = points[i + 3];

            }

        // only Y

        } else if (eb == 'y')

            if (yerr.asymmetric) {

                eyl = points[i + 2];

                eyu = points[i + 3];

            } else eyl = points[i + 2];



        // symmetric errors?

        if (exu == null) exu = exl;

        if (eyu == null) eyu = eyl;



        var errRanges = [exl, exu, eyl, eyu];

        // nullify if not showing

        if (!xerr.show){

            errRanges[0] = null;

            errRanges[1] = null;

        }

        if (!yerr.show){

            errRanges[2] = null;

            errRanges[3] = null;

        }

        return errRanges;

    }



    function drawSeriesErrors(plot, ctx, s){



        var points = s.datapoints.points,

                ps = s.datapoints.pointsize,

                ax = [s.xaxis, s.yaxis],

                radius = s.points.radius,

                err = [s.points.xerr, s.points.yerr];



        //sanity check, in case some inverted axis hack is applied to flot

        var invertX = false;

        if (ax[0].p2c(ax[0].max) < ax[0].p2c(ax[0].min)) {

            invertX = true;

            var tmp = err[0].lowerCap;

            err[0].lowerCap = err[0].upperCap;

            err[0].upperCap = tmp;

        }



        var invertY = false;

        if (ax[1].p2c(ax[1].min) < ax[1].p2c(ax[1].max)) {

            invertY = true;

            var tmp = err[1].lowerCap;

            err[1].lowerCap = err[1].upperCap;

            err[1].upperCap = tmp;

        }



        for (var i = 0; i < s.datapoints.points.length; i += ps) {



            //parse

            var errRanges = parseErrors(s, i);



            //cycle xerr & yerr

            for (var e = 0; e < err.length; e++){



                var minmax = [ax[e].min, ax[e].max];



                //draw this error?

                if (errRanges[e * err.length]){



                    //data coordinates

                    var x = points[i],

                        y = points[i + 1];



                    //errorbar ranges

                    var upper = [x, y][e] + errRanges[e * err.length + 1],

                        lower = [x, y][e] - errRanges[e * err.length];



                    //points outside of the canvas

                    if (err[e].err == 'x')

                        if (y > ax[1].max || y < ax[1].min || upper < ax[0].min || lower > ax[0].max)

                            continue;

                    if (err[e].err == 'y')

                        if (x > ax[0].max || x < ax[0].min || upper < ax[1].min || lower > ax[1].max)

                            continue;



                    // prevent errorbars getting out of the canvas

                    var drawUpper = true,

                        drawLower = true;



                    if (upper > minmax[1]) {

                        drawUpper = false;

                        upper = minmax[1];

                    }

                    if (lower < minmax[0]) {

                        drawLower = false;

                        lower = minmax[0];

                    }



                    //sanity check, in case some inverted axis hack is applied to flot

                    if ((err[e].err == 'x' && invertX) || (err[e].err == 'y' && invertY)) {

                        //swap coordinates

                        var tmp = lower;

                        lower = upper;

                        upper = tmp;

                        tmp = drawLower;

                        drawLower = drawUpper;

                        drawUpper = tmp;

                        tmp = minmax[0];

                        minmax[0] = minmax[1];

                        minmax[1] = tmp;

                    }



                    // convert to pixels

                    x = ax[0].p2c(x),

                        y = ax[1].p2c(y),

                        upper = ax[e].p2c(upper);

                    lower = ax[e].p2c(lower);

                    minmax[0] = ax[e].p2c(minmax[0]);

                    minmax[1] = ax[e].p2c(minmax[1]);



                    //same style as points by default

                    var lw = err[e].lineWidth ? err[e].lineWidth : s.points.lineWidth,

                        sw = s.points.shadowSize != null ? s.points.shadowSize : s.shadowSize;



                    //shadow as for points

                    if (lw > 0 && sw > 0) {

                        var w = sw / 2;

                        ctx.lineWidth = w;

                        ctx.strokeStyle = "rgba(0,0,0,0.1)";

                        drawError(ctx, err[e], x, y, upper, lower, drawUpper, drawLower, radius, w + w/2, minmax);



                        ctx.strokeStyle = "rgba(0,0,0,0.2)";

                        drawError(ctx, err[e], x, y, upper, lower, drawUpper, drawLower, radius, w/2, minmax);

                    }



                    ctx.strokeStyle = err[e].color? err[e].color: s.color;

                    ctx.lineWidth = lw;

                    //draw it

                    drawError(ctx, err[e], x, y, upper, lower, drawUpper, drawLower, radius, 0, minmax);

                }

            }

        }

    }



    function drawError(ctx,err,x,y,upper,lower,drawUpper,drawLower,radius,offset,minmax){



        //shadow offset

        y += offset;

        upper += offset;

        lower += offset;



        // error bar - avoid plotting over circles

        if (err.err == 'x'){

            if (upper > x + radius) drawPath(ctx, [[upper,y],[Math.max(x + radius,minmax[0]),y]]);

            else drawUpper = false;

            if (lower < x - radius) drawPath(ctx, [[Math.min(x - radius,minmax[1]),y],[lower,y]] );

            else drawLower = false;

        }

        else {

            if (upper < y - radius) drawPath(ctx, [[x,upper],[x,Math.min(y - radius,minmax[0])]] );

            else drawUpper = false;

            if (lower > y + radius) drawPath(ctx, [[x,Math.max(y + radius,minmax[1])],[x,lower]] );

            else drawLower = false;

        }



        //internal radius value in errorbar, allows to plot radius 0 points and still keep proper sized caps

        //this is a way to get errorbars on lines without visible connecting dots

        radius = err.radius != null? err.radius: radius;



        // upper cap

        if (drawUpper) {

            if (err.upperCap == '-'){

                if (err.err=='x') drawPath(ctx, [[upper,y - radius],[upper,y + radius]] );

                else drawPath(ctx, [[x - radius,upper],[x + radius,upper]] );

            } else if ($.isFunction(err.upperCap)){

                if (err.err=='x') err.upperCap(ctx, upper, y, radius);

                else err.upperCap(ctx, x, upper, radius);

            }

        }

        // lower cap

        if (drawLower) {

            if (err.lowerCap == '-'){

                if (err.err=='x') drawPath(ctx, [[lower,y - radius],[lower,y + radius]] );

                else drawPath(ctx, [[x - radius,lower],[x + radius,lower]] );

            } else if ($.isFunction(err.lowerCap)){

                if (err.err=='x') err.lowerCap(ctx, lower, y, radius);

                else err.lowerCap(ctx, x, lower, radius);

            }

        }

    }



    function drawPath(ctx, pts){

        ctx.beginPath();

        ctx.moveTo(pts[0][0], pts[0][1]);

        for (var p=1; p < pts.length; p++)

            ctx.lineTo(pts[p][0], pts[p][1]);

        ctx.stroke();

    }



    function draw(plot, ctx){

        var plotOffset = plot.getPlotOffset();



        ctx.save();

        ctx.translate(plotOffset.left, plotOffset.top);

        $.each(plot.getData(), function (i, s) {

            if (s.points.errorbars && (s.points.xerr.show || s.points.yerr.show))

                drawSeriesErrors(plot, ctx, s);

        });

        ctx.restore();

    }



    function init(plot) {

        plot.hooks.processRawData.push(processRawData);

        plot.hooks.draw.push(draw);

    }



    $.plot.plugins.push({

                init: init,

                options: options,

                name: 'errorbars',

                version: '1.0'

            });

})(jQuery);

