datahandler/default-fractions.js

   1 /**
   2  * @license
   3  * Copyright 2013 David Eberlein (david.eberlein@ch.sauter-bc.com)
   4  * MIT-licensed (http://opensource.org/licenses/MIT)
   5  */
   6
   7 /**
   8  * @fileoverview DataHandler implementation for the fractions option.
   9  * @author David Eberlein (david.eberlein@ch.sauter-bc.com)
  10  */
  11
  12 (function() {
  13   /*global Dygraph:false */
  14   "use strict";
  15
  16   var DefaultFractionHandler = Dygraph.DataHandler();
  17   DefaultFractionHandler.prototype = Dygraph.DataHandlers.createHandler("default");
  18   Dygraph.DataHandlers.registerHandler("default-fractions", DefaultFractionHandler);
  19
  20   DefaultFractionHandler.prototype.extractSeries = function(rawData, i, options) {
  21     // TODO(danvk): pre-allocate series here.
  22     var series = [];
  23     var x, y, point, num, den, value;
  24     var mult = 100.0;
  25     var logScale = options.get('logscale');
  26     for ( var j = 0; j < rawData.length; j++) {
  27       x = rawData[j][0];
  28       point = rawData[j][i];
  29       if (logScale && point !== null) {
  30         // On the log scale, points less than zero do not exist.
  31         // This will create a gap in the chart.
  32         if (point[0] <= 0 || point[1] <= 0) {
  33           point = null;
  34         }
  35       }
  36       // Extract to the unified data format.
  37       if (point !== null) {
  38         num = point[0];
  39         den = point[1];
  40         if (num !== null && !isNaN(num)) {
  41           value = den ? num / den : 0.0;
  42           y = mult * value;
  43           // preserve original values in extras for further filtering
  44           series.push([ x, y, [ num, den ] ]);
  45         } else {
  46           series.push([ x, num, [ num, den ] ]);
  47         }
  48       } else {
  49         series.push([ x, null, [ null, null ] ]);
  50       }
  51     }
  52     return series;
  53   };
  54
  55   DefaultFractionHandler.prototype.rollingAverage = function(originalData, rollPeriod,
  56       options) {
  57     rollPeriod = Math.min(rollPeriod, originalData.length);
  58     var rollingData = [];
  59
  60     var i;
  61     var num = 0;
  62     var den = 0; // numerator/denominator
  63     var mult = 100.0;
  64     for (i = 0; i < originalData.length; i++) {
  65       num += originalData[i][2][0];
  66       den += originalData[i][2][1];
  67       if (i - rollPeriod >= 0) {
  68         num -= originalData[i - rollPeriod][2][0];
  69         den -= originalData[i - rollPeriod][2][1];
  70       }
  71
  72       var date = originalData[i][0];
  73       var value = den ? num / den : 0.0;
  74       rollingData[i] = [ date, mult * value ];
  75     }
  76
  77     return rollingData;
  78   };
  79 })();