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      1 /* Flot plugin for thresholding data.
      2 
      3 Copyright (c) 2007-2014 IOLA and Ole Laursen.
      4 Licensed under the MIT license.
      5 
      6 The plugin supports these options:
      7 
      8 	series: {
      9 		threshold: {
     10 			below: number
     11 			color: colorspec
     12 		}
     13 	}
     14 
     15 It can also be applied to a single series, like this:
     16 
     17 	$.plot( $("#placeholder"), [{
     18 		data: [ ... ],
     19 		threshold: { ... }
     20 	}])
     21 
     22 An array can be passed for multiple thresholding, like this:
     23 
     24 	threshold: [{
     25 		below: number1
     26 		color: color1
     27 	},{
     28 		below: number2
     29 		color: color2
     30 	}]
     31 
     32 These multiple threshold objects can be passed in any order since they are
     33 sorted by the processing function.
     34 
     35 The data points below "below" are drawn with the specified color. This makes
     36 it easy to mark points below 0, e.g. for budget data.
     37 
     38 Internally, the plugin works by splitting the data into two series, above and
     39 below the threshold. The extra series below the threshold will have its label
     40 cleared and the special "originSeries" attribute set to the original series.
     41 You may need to check for this in hover events.
     42 
     43 */
     44 
     45 (function ($) {
     46     var options = {
     47         series: { threshold: null } // or { below: number, color: color spec}
     48     };
     49 
     50     function init(plot) {
     51         function thresholdData(plot, s, datapoints, below, color) {
     52             var ps = datapoints.pointsize, i, x, y, p, prevp,
     53                 thresholded = $.extend({}, s); // note: shallow copy
     54 
     55             thresholded.datapoints = { points: [], pointsize: ps, format: datapoints.format };
     56             thresholded.label = null;
     57             thresholded.color = color;
     58             thresholded.threshold = null;
     59             thresholded.originSeries = s;
     60             thresholded.data = [];
     61 
     62             var origpoints = datapoints.points,
     63                 addCrossingPoints = s.lines.show;
     64 
     65             var threspoints = [];
     66             var newpoints = [];
     67             var m;
     68 
     69             for (i = 0; i < origpoints.length; i += ps) {
     70                 x = origpoints[i];
     71                 y = origpoints[i + 1];
     72 
     73                 prevp = p;
     74                 if (y < below)
     75                     p = threspoints;
     76                 else
     77                     p = newpoints;
     78 
     79                 if (addCrossingPoints && prevp != p && x != null
     80                     && i > 0 && origpoints[i - ps] != null) {
     81                     var interx = x + (below - y) * (x - origpoints[i - ps]) / (y - origpoints[i - ps + 1]);
     82                     prevp.push(interx);
     83                     prevp.push(below);
     84                     for (m = 2; m < ps; ++m)
     85                         prevp.push(origpoints[i + m]);
     86 
     87                     p.push(null); // start new segment
     88                     p.push(null);
     89                     for (m = 2; m < ps; ++m)
     90                         p.push(origpoints[i + m]);
     91                     p.push(interx);
     92                     p.push(below);
     93                     for (m = 2; m < ps; ++m)
     94                         p.push(origpoints[i + m]);
     95                 }
     96 
     97                 p.push(x);
     98                 p.push(y);
     99                 for (m = 2; m < ps; ++m)
    100                     p.push(origpoints[i + m]);
    101             }
    102 
    103             datapoints.points = newpoints;
    104             thresholded.datapoints.points = threspoints;
    105 
    106             if (thresholded.datapoints.points.length > 0) {
    107                 var origIndex = $.inArray(s, plot.getData());
    108                 // Insert newly-generated series right after original one (to prevent it from becoming top-most)
    109                 plot.getData().splice(origIndex + 1, 0, thresholded);
    110             }
    111 
    112             // FIXME: there are probably some edge cases left in bars
    113         }
    114 
    115         function processThresholds(plot, s, datapoints) {
    116             if (!s.threshold)
    117                 return;
    118 
    119             if (s.threshold instanceof Array) {
    120                 s.threshold.sort(function(a, b) {
    121                     return a.below - b.below;
    122                 });
    123 
    124                 $(s.threshold).each(function(i, th) {
    125                     thresholdData(plot, s, datapoints, th.below, th.color);
    126                 });
    127             }
    128             else {
    129                 thresholdData(plot, s, datapoints, s.threshold.below, s.threshold.color);
    130             }
    131         }
    132 
    133         plot.hooks.processDatapoints.push(processThresholds);
    134     }
    135 
    136     $.plot.plugins.push({
    137         init: init,
    138         options: options,
    139         name: 'threshold',
    140         version: '1.2'
    141     });
    142 })(jQuery);
    143