152 lines
5.3 KiB
JavaScript
152 lines
5.3 KiB
JavaScript
/*
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Flot plugin for stacking data sets, i.e. putting them on top of each
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other, for accumulative graphs. Note that the plugin assumes the data
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is sorted on x. Also note that stacking a mix of positive and negative
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values 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
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the same key (which can be any number or string or just "true"). To
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specify the default stack, you can set
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series: {
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stack: null or true or key (number/string)
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}
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or specify it for a specific series
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$.plot($("#placeholder"), [{ data: [ ... ], stack: true ])
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The stacking order is determined by the order of the data series in
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the array (later series end up on top of the previous).
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Internally, the plugin modifies the datapoints in each series, adding
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an offset to the y value. For line series, extra data points are
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inserted through interpolation. For bar charts, the second y value is
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also adjusted.
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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)
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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, withbars = s.bars.show,
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withsteps = withlines && s.lines.steps,
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i = 0, j = 0, l;
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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 (j >= otherpoints.length
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|| otherpoints[j] == null
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|| points[i] == null) {
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// degenerate cases
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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 {
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// cases where we actually got two points
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px = points[i];
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py = points[i + 1];
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qx = otherpoints[j];
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qy = otherpoints[j + 1];
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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 + 1] += 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 + 1] - py) * (qx - px) / (points[i - ps] - 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 {
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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 - ps] != null)
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bottom = qy + (otherpoints[j - ps + 1] - qy) * (px - qx) / (otherpoints[j - ps] - qx);
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newpoints[l + 1] += bottom;
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i += ps;
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}
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if (l != newpoints.length && withbars)
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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: '1.0'
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});
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})(jQuery);
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