src/datahandler/default.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 default implementation used for simple line charts.
   9  * @author David Eberlein (david.eberlein@ch.sauter-bc.com)
  10  */
  11
  12 (function() {
  13
  14 /*global Dygraph:false */
  15 "use strict";
  16
  17 /**
  18  * @constructor
  19  * @extends Dygraph.DataHandler
  20  */
  21 Dygraph.DataHandlers.DefaultHandler = function() {
  22 };
  23
  24 var DefaultHandler = Dygraph.DataHandlers.DefaultHandler;
  25 DefaultHandler.prototype = new Dygraph.DataHandler();
  26
  27 /** @inheritDoc */
  28 DefaultHandler.prototype.extractSeries = function(rawData, i, options) {
  29   // TODO(danvk): pre-allocate series here.
  30   var series = [];
  31   var logScale = options.get('logscale');
  32   for ( var j = 0; j < rawData.length; j++) {
  33     var x = rawData[j][0];
  34     var point = rawData[j][i];
  35     if (logScale) {
  36       // On the log scale, points less than zero do not exist.
  37       // This will create a gap in the chart.
  38       if (point <= 0) {
  39         point = null;
  40       }
  41     }
  42     series.push([ x, point ]);
  43   }
  44   return series;
  45 };
  46
  47 /** @inheritDoc */
  48 DefaultHandler.prototype.rollingAverage = function(originalData, rollPeriod,
  49     options) {
  50   rollPeriod = Math.min(rollPeriod, originalData.length);
  51   var rollingData = [];
  52
  53   var i, j, y, sum, num_ok;
  54   // Calculate the rolling average for the first rollPeriod - 1 points
  55   // where
  56   // there is not enough data to roll over the full number of points
  57   if (rollPeriod == 1) {
  58     return originalData;
  59   }
  60   for (i = 0; i < originalData.length; i++) {
  61     sum = 0;
  62     num_ok = 0;
  63     for (j = Math.max(0, i - rollPeriod + 1); j < i + 1; j++) {
  64       y = originalData[j][1];
  65       if (y === null || isNaN(y))
  66         continue;
  67       num_ok++;
  68       sum += originalData[j][1];
  69     }
  70     if (num_ok) {
  71       rollingData[i] = [ originalData[i][0], sum / num_ok ];
  72     } else {
  73       rollingData[i] = [ originalData[i][0], null ];
  74     }
  75   }
  76
  77   return rollingData;
  78 };
  79
  80 /** @inheritDoc */
  81 DefaultHandler.prototype.getExtremeYValues = function(series, dateWindow,
  82     options) {
  83   var minY = null, maxY = null, y;
  84   var firstIdx = 0, lastIdx = series.length - 1;
  85
  86   for ( var j = firstIdx; j <= lastIdx; j++) {
  87     y = series[j][1];
  88     if (y === null || isNaN(y))
  89       continue;
  90     if (maxY === null || y > maxY) {
  91       maxY = y;
  92     }
  93     if (minY === null || y < minY) {
  94       minY = y;
  95     }
  96   }
  97   return [ minY, maxY ];
  98 };
  99
 100 })();