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/* |
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Flot plugin for computing bottoms for filled line and bar charts. |
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|
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The case: you've got two series that you want to fill the area |
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between. In Flot terms, you need to use one as the fill bottom of the |
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other. You can specify the bottom of each data point as the third |
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coordinate manually, or you can use this plugin to compute it for you. |
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|
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In order to name the other series, you need to give it an id, like this |
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|
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var dataset = [ |
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{ data: [ ... ], id: "foo" } , // use default bottom |
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{ data: [ ... ], fillBetween: "foo" }, // use first dataset as bottom |
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]; |
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|
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$.plot($("#placeholder"), dataset, { line: { show: true, fill: true }}); |
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|
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As a convenience, if the id given is a number that doesn't appear as |
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an id in the series, it is interpreted as the index in the array |
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instead (so fillBetween: 0 can also mean the first series). |
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|
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Internally, the plugin modifies the datapoints in each series. For |
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line series, extra data points might be inserted through |
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interpolation. Note that at points where the bottom line is not |
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defined (due to a null point or start/end of line), the current line |
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will show a gap too. The algorithm comes from the jquery.flot.stack.js |
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plugin, possibly some code could be shared. |
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*/ |
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|
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(function ($) { |
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var options = { |
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series: { fillBetween: null } // or number |
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}; |
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|
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function init(plot) { |
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function findBottomSeries(s, allseries) { |
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var i; |
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for (i = 0; i < allseries.length; ++i) { |
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if (allseries[i].id == s.fillBetween) |
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return allseries[i]; |
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} |
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|
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if (typeof s.fillBetween == "number") { |
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i = s.fillBetween; |
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|
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if (i < 0 || i >= allseries.length) |
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return null; |
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|
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return allseries[i]; |
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} |
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|
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return null; |
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} |
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|
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function computeFillBottoms(plot, s, datapoints) { |
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if (s.fillBetween == null) |
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return; |
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|
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var other = findBottomSeries(s, plot.getData()); |
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if (!other) |
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return; |
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|
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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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withbottom = ps > 2 && datapoints.format[2].y, |
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withsteps = withlines && s.lines.steps, |
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fromgap = true, |
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i = 0, j = 0, l; |
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|
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while (true) { |
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if (i >= points.length) |
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break; |
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|
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l = newpoints.length; |
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|
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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]; |
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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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|
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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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|
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//newpoints[l + 1] += qy; |
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bottom = qy; |
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|
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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) |
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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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|
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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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|
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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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// 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 + 1] - qy) * (px - qx) / (otherpoints[j - otherps] - qx); |
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|
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//newpoints[l + 1] += bottom; |
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|
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i += ps; |
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} |
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|
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fromgap = false; |
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|
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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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|
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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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|
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datapoints.points = newpoints; |
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} |
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|
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plot.hooks.processDatapoints.push(computeFillBottoms); |
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} |
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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: 'fillbetween', |
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version: '1.0' |
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}); |
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})(jQuery); |
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|
