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Diffstat (limited to 'jquery.flot.fillbetween.js')
| -rw-r--r-- | jquery.flot.fillbetween.js | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/jquery.flot.fillbetween.js b/jquery.flot.fillbetween.js new file mode 100644 index 0000000..69700e7 --- /dev/null +++ b/jquery.flot.fillbetween.js @@ -0,0 +1,183 @@ +/* +Flot plugin for computing bottoms for filled line and bar charts. + +The case: you've got two series that you want to fill the area +between. In Flot terms, you need to use one as the fill bottom of the +other. You can specify the bottom of each data point as the third +coordinate manually, or you can use this plugin to compute it for you. + +In order to name the other series, you need to give it an id, like this + + var dataset = [ + { data: [ ... ], id: "foo" } , // use default bottom + { data: [ ... ], fillBetween: "foo" }, // use first dataset as bottom + ]; + + $.plot($("#placeholder"), dataset, { line: { show: true, fill: true }}); + +As a convenience, if the id given is a number that doesn't appear as +an id in the series, it is interpreted as the index in the array +instead (so fillBetween: 0 can also mean the first series). + +Internally, the plugin modifies the datapoints in each series. For +line series, extra data points might be inserted through +interpolation. Note that at points where the bottom line is not +defined (due to a null point or start/end of line), the current line +will show a gap too. The algorithm comes from the jquery.flot.stack.js +plugin, possibly some code could be shared. +*/ + +(function ($) { + var options = { + series: { fillBetween: null } // or number + }; + + function init(plot) { + function findBottomSeries(s, allseries) { + var i; + for (i = 0; i < allseries.length; ++i) { + if (allseries[i].id == s.fillBetween) + return allseries[i]; + } + + if (typeof s.fillBetween == "number") { + i = s.fillBetween; + + if (i < 0 || i >= allseries.length) + return null; + + return allseries[i]; + } + + return null; + } + + function computeFillBottoms(plot, s, datapoints) { + if (s.fillBetween == null) + return; + + var other = findBottomSeries(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, + withbottom = ps > 2 && datapoints.format[2].y, + withsteps = withlines && s.lines.steps, + fromgap = true, + i = 0, j = 0, l; + + while (true) { + if (i >= points.length) + break; + + l = newpoints.length; + + if (points[i] == null) { + // copy gaps + for (m = 0; m < ps; ++m) + newpoints.push(points[i + m]); + i += ps; + } + else if (j >= otherpoints.length) { + // for lines, we can't use the rest of the points + if (!withlines) { + for (m = 0; m < ps; ++m) + newpoints.push(points[i + m]); + } + i += ps; + } + else if (otherpoints[j] == null) { + // oops, got a gap + for (m = 0; m < ps; ++m) + newpoints.push(null); + fromgap = true; + j += otherps; + } + 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) + for (m = 2; m < ps; ++m) + newpoints.push(points[i + m]); + bottom = qy; + } + + j += otherps; + } + else { // px < qx + if (fromgap && withlines) { + // if we come from a gap, we just skip this point + i += ps; + continue; + } + + 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 - otherps] != null) + bottom = qy + (otherpoints[j - otherps + 1] - qy) * (px - qx) / (otherpoints[j - otherps] - qx); + + //newpoints[l + 1] += bottom; + + i += ps; + } + + fromgap = false; + + if (l != newpoints.length && withbottom) + 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(computeFillBottoms); + } + + $.plot.plugins.push({ + init: init, + options: options, + name: 'fillbetween', + version: '1.0' + }); +})(jQuery); |