EPSIAE » eneraptor

/*

Flot plugin for stacking data sets, i.e. putting them on top of each

other, for accumulative graphs. Note that the plugin assumes the data

is sorted on x. Also note that stacking a mix of positive and negative

values in most instances doesn't make sense (so it looks weird).

Two or more series are stacked when their "stack" attribute is set to

the same key (which can be any number or string or just "true"). To

specify the default stack, you can set

  series: {

    stack: null or true or key (number/string)

  }

or specify it for a specific series

  $.plot($("#placeholder"), [{ data: [ ... ], stack: true ])

The stacking order is determined by the order of the data series in

the array (later series end up on top of the previous).

Internally, the plugin modifies the datapoints in each series, adding

an offset to the y value. For line series, extra data points are

inserted through interpolation. For bar charts, the second y value is

also adjusted.

*/

(function ($) {

    var options = {

        series: { stack: null } // or number/string

    };

    function init(plot) {

        function findMatchingSeries(s, allseries) {

            var res = null

            for (var i = 0; i < allseries.length; ++i) {

                if (s == allseries[i])

                    break;

                if (allseries[i].stack == s.stack)

                    res = allseries[i];

            }

            return res;

        }

        function stackData(plot, s, datapoints) {

            if (s.stack == null)

                return;

            var other = findMatchingSeries(s, plot.getData());

            if (!other)

                return;

            var ps = datapoints.pointsize,

                points = datapoints.points,

                otherps = other.datapoints.pointsize,

                otherpoints = other.datapoints.points,

                newpoints = [],

                px, py, intery, qx, qy, bottom,

                withlines = s.lines.show, withbars = s.bars.show,

                withsteps = withlines && s.lines.steps,

                i = 0, j = 0, l;

            while (true) {

                if (i >= points.length)

                    break;

                l = newpoints.length;

                if (j >= otherpoints.length

                    || otherpoints[j] == null

                    || points[i] == null) {

                    // degenerate cases

                    for (m = 0; m < ps; ++m)

                        newpoints.push(points[i + m]);

                    i += ps;

                }

                else {

                    // cases where we actually got two points

                    px = points[i];

                    py = points[i + 1];

                    qx = otherpoints[j];

                    qy = otherpoints[j + 1];

                    bottom = 0;

                    if (px == qx) {

                        for (m = 0; m < ps; ++m)

                            newpoints.push(points[i + m]);

                        newpoints[l + 1] += qy;

                        bottom = qy;

                        i += ps;

                        j += otherps;

                    }

                    else if (px > qx) {

                        // we got past point below, might need to

                        // insert interpolated extra point

                        if (withlines && i > 0 && points[i - ps] != null) {

                            intery = py + (points[i - ps + 1] - py) * (qx - px) / (points[i - ps] - px);

                            newpoints.push(qx);

                            newpoints.push(intery + qy)

                            for (m = 2; m < ps; ++m)

                                newpoints.push(points[i + m]);

                            bottom = qy; 

                        }

                        j += otherps;

                    }

                    else {

                        for (m = 0; m < ps; ++m)

                            newpoints.push(points[i + m]);

                        // we might be able to interpolate a point below,

                        // this can give us a better y

                        if (withlines && j > 0 && otherpoints[j - ps] != null)

                            bottom = qy + (otherpoints[j - ps + 1] - qy) * (px - qx) / (otherpoints[j - ps] - qx);

                        newpoints[l + 1] += bottom;

                        i += ps;

                    }

                    if (l != newpoints.length && withbars)

                        newpoints[l + 2] += bottom;

                }

                // maintain the line steps invariant

                if (withsteps && l != newpoints.length && l > 0

                    && newpoints[l] != null

                    && newpoints[l] != newpoints[l - ps]

                    && newpoints[l + 1] != newpoints[l - ps + 1]) {

                    for (m = 0; m < ps; ++m)

                        newpoints[l + ps + m] = newpoints[l + m];

                    newpoints[l + 1] = newpoints[l - ps + 1];

                }

            }

            datapoints.points = newpoints;

        }

        plot.hooks.processDatapoints.push(stackData);

    }

    $.plot.plugins.push({

        init: init,

        options: options,

        name: 'stack',

        version: '1.0'

    });

})(jQuery);