1 /* Flot plugin for stacking data sets rather than overlyaing them.
3 Copyright (c) 2007-2013 IOLA and Ole Laursen.
4 Licensed under the MIT license.
6 The plugin assumes the data is sorted on x (or y if stacking horizontally).
7 For line charts, it is assumed that if a line has an undefined gap (from a
8 null point), then the line above it should have the same gap - insert zeros
9 instead of "null" if you want another behaviour. This also holds for the start
10 and end of the chart. Note that stacking a mix of positive and negative values
11 in most instances doesn't make sense (so it looks weird).
13 Two or more series are stacked when their "stack" attribute is set to the same
14 key (which can be any number or string or just "true"). To specify the default
15 stack, you can set the stack option like this:
18 stack: null/false, true, or a key (number/string)
21 You can also specify it for a single series, like this:
23 $.plot( $("#placeholder"), [{
28 The stacking order is determined by the order of the data series in the array
29 (later series end up on top of the previous).
31 Internally, the plugin modifies the datapoints in each series, adding an
32 offset to the y value. For line series, extra data points are inserted through
33 interpolation. If there's a second y value, it's also adjusted (e.g for bar
34 charts or filled areas).
40 series: { stack: null } // or number/string
44 function findMatchingSeries(s, allseries) {
46 for (var i = 0; i < allseries.length; ++i) {
47 if (s == allseries[i])
50 if (allseries[i].stack == s.stack)
57 function stackData(plot, s, datapoints) {
58 if (s.stack == null || s.stack === false)
61 var other = findMatchingSeries(s, plot.getData());
65 var ps = datapoints.pointsize,
66 points = datapoints.points,
67 otherps = other.datapoints.pointsize,
68 otherpoints = other.datapoints.points,
70 px, py, intery, qx, qy, bottom,
71 withlines = s.lines.show,
72 horizontal = s.bars.horizontal,
73 withbottom = ps > 2 && (horizontal ? datapoints.format[2].x : datapoints.format[2].y),
74 withsteps = withlines && s.lines.steps,
76 keyOffset = horizontal ? 1 : 0,
77 accumulateOffset = horizontal ? 0 : 1,
81 if (i >= points.length)
86 if (points[i] == null) {
88 for (m = 0; m < ps; ++m)
89 newpoints.push(points[i + m]);
92 else if (j >= otherpoints.length) {
93 // for lines, we can't use the rest of the points
95 for (m = 0; m < ps; ++m)
96 newpoints.push(points[i + m]);
100 else if (otherpoints[j] == null) {
102 for (m = 0; m < ps; ++m)
103 newpoints.push(null);
108 // cases where we actually got two points
109 px = points[i + keyOffset];
110 py = points[i + accumulateOffset];
111 qx = otherpoints[j + keyOffset];
112 qy = otherpoints[j + accumulateOffset];
116 for (m = 0; m < ps; ++m)
117 newpoints.push(points[i + m]);
119 newpoints[l + accumulateOffset] += qy;
126 // we got past point below, might need to
127 // insert interpolated extra point
128 if (withlines && i > 0 && points[i - ps] != null) {
129 intery = py + (points[i - ps + accumulateOffset] - py) * (qx - px) / (points[i - ps + keyOffset] - px);
131 newpoints.push(intery + qy);
132 for (m = 2; m < ps; ++m)
133 newpoints.push(points[i + m]);
140 if (fromgap && withlines) {
141 // if we come from a gap, we just skip this point
146 for (m = 0; m < ps; ++m)
147 newpoints.push(points[i + m]);
149 // we might be able to interpolate a point below,
150 // this can give us a better y
151 if (withlines && j > 0 && otherpoints[j - otherps] != null)
152 bottom = qy + (otherpoints[j - otherps + accumulateOffset] - qy) * (px - qx) / (otherpoints[j - otherps + keyOffset] - qx);
154 newpoints[l + accumulateOffset] += bottom;
161 if (l != newpoints.length && withbottom)
162 newpoints[l + 2] += bottom;
165 // maintain the line steps invariant
166 if (withsteps && l != newpoints.length && l > 0
167 && newpoints[l] != null
168 && newpoints[l] != newpoints[l - ps]
169 && newpoints[l + 1] != newpoints[l - ps + 1]) {
170 for (m = 0; m < ps; ++m)
171 newpoints[l + ps + m] = newpoints[l + m];
172 newpoints[l + 1] = newpoints[l - ps + 1];
176 datapoints.points = newpoints;
179 plot.hooks.processDatapoints.push(stackData);
182 $.plot.plugins.push({