/* Flot plugin for stacking data sets rather than overlyaing them.
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Copyright (c) 2007-2013 IOLA and Ole Laursen.
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Licensed under the MIT license.
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The plugin assumes the data is sorted on x (or y if stacking horizontally).
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For line charts, it is assumed that if a line has an undefined gap (from a
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null point), then the line above it should have the same gap - insert zeros
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instead of "null" if you want another behaviour. This also holds for the start
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and end of the chart. Note that stacking a mix of positive and negative values
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in most instances doesn't make sense (so it looks weird).
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Two or more series are stacked when their "stack" attribute is set to the same
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key (which can be any number or string or just "true"). To specify the default
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stack, you can set the stack option like this:
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series: {
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stack: null/false, true, or a key (number/string)
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}
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You can also specify it for a single series, like this:
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$.plot( $("#placeholder"), [{
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data: [ ... ],
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stack: true
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}])
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The stacking order is determined by the order of the data series in the array
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(later series end up on top of the previous).
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Internally, the plugin modifies the datapoints in each series, adding an
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offset to the y value. For line series, extra data points are inserted through
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interpolation. If there's a second y value, it's also adjusted (e.g for bar
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charts or filled areas).
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*/
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(function ($) {
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var options = {
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series: { stack: null } // or number/string
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};
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function init(plot) {
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function findMatchingSeries(s, allseries) {
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var res = null;
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for (var i = 0; i < allseries.length; ++i) {
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if (s == allseries[i])
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break;
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if (allseries[i].stack == s.stack)
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res = allseries[i];
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}
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return res;
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}
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function stackData(plot, s, datapoints) {
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if (s.stack == null || s.stack === false)
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return;
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var other = findMatchingSeries(s, plot.getData());
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if (!other)
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return;
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var ps = datapoints.pointsize,
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points = datapoints.points,
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otherps = other.datapoints.pointsize,
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otherpoints = other.datapoints.points,
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newpoints = [],
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px, py, intery, qx, qy, bottom,
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withlines = s.lines.show,
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horizontal = s.bars.horizontal,
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withbottom = ps > 2 && (horizontal ? datapoints.format[2].x : datapoints.format[2].y),
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withsteps = withlines && s.lines.steps,
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fromgap = true,
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keyOffset = horizontal ? 1 : 0,
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accumulateOffset = horizontal ? 0 : 1,
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i = 0, j = 0, l, m;
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while (true) {
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if (i >= points.length)
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break;
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l = newpoints.length;
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if (points[i] == null) {
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// copy gaps
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for (m = 0; m < ps; ++m)
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newpoints.push(points[i + m]);
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i += ps;
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}
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else if (j >= otherpoints.length) {
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// for lines, we can't use the rest of the points
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if (!withlines) {
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for (m = 0; m < ps; ++m)
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newpoints.push(points[i + m]);
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}
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i += ps;
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}
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else if (otherpoints[j] == null) {
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// oops, got a gap
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for (m = 0; m < ps; ++m)
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newpoints.push(null);
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fromgap = true;
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j += otherps;
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}
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else {
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// cases where we actually got two points
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px = points[i + keyOffset];
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py = points[i + accumulateOffset];
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qx = otherpoints[j + keyOffset];
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qy = otherpoints[j + accumulateOffset];
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bottom = 0;
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if (px == qx) {
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for (m = 0; m < ps; ++m)
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newpoints.push(points[i + m]);
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newpoints[l + accumulateOffset] += qy;
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bottom = qy;
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i += ps;
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j += otherps;
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}
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else if (px > qx) {
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// we got past point below, might need to
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// insert interpolated extra point
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if (withlines && i > 0 && points[i - ps] != null) {
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intery = py + (points[i - ps + accumulateOffset] - py) * (qx - px) / (points[i - ps + keyOffset] - px);
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newpoints.push(qx);
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newpoints.push(intery + qy);
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for (m = 2; m < ps; ++m)
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newpoints.push(points[i + m]);
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bottom = qy;
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}
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j += otherps;
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}
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else { // px < qx
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if (fromgap && withlines) {
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// if we come from a gap, we just skip this point
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i += ps;
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continue;
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}
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for (m = 0; m < ps; ++m)
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newpoints.push(points[i + m]);
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// we might be able to interpolate a point below,
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// this can give us a better y
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if (withlines && j > 0 && otherpoints[j - otherps] != null)
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bottom = qy + (otherpoints[j - otherps + accumulateOffset] - qy) * (px - qx) / (otherpoints[j - otherps + keyOffset] - qx);
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newpoints[l + accumulateOffset] += bottom;
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i += ps;
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}
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fromgap = false;
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if (l != newpoints.length && withbottom)
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newpoints[l + 2] += bottom;
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}
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// maintain the line steps invariant
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if (withsteps && l != newpoints.length && l > 0
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&& newpoints[l] != null
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&& newpoints[l] != newpoints[l - ps]
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&& newpoints[l + 1] != newpoints[l - ps + 1]) {
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for (m = 0; m < ps; ++m)
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newpoints[l + ps + m] = newpoints[l + m];
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newpoints[l + 1] = newpoints[l - ps + 1];
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}
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}
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datapoints.points = newpoints;
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}
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plot.hooks.processDatapoints.push(stackData);
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}
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$.plot.plugins.push({
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init: init,
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options: options,
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name: 'stack',
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version: '1.2'
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});
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})(jQuery);
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