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 Dygraph.DataHandlers.DefaultHandler = Dygraph.DataHandler();
  18 var DefaultHandler = Dygraph.DataHandlers.DefaultHandler;
  19
  20 DefaultHandler.prototype.extractSeries = function(rawData, i, options) {
  21   // TODO(danvk): pre-allocate series here.
  22   var series = [];
  23   var logScale = options.get('logscale');
  24   for ( var j = 0; j < rawData.length; j++) {
  25     var x = rawData[j][0];
  26     var point = rawData[j][i];
  27     if (logScale) {
  28       // On the log scale, points less than zero do not exist.
  29       // This will create a gap in the chart.
  30       if (point <= 0) {
  31         point = null;
  32       }
  33     }
  34     series.push([ x, point ]);
  35   }
  36   return series;
  37 };
  38
  39 DefaultHandler.prototype.rollingAverage = function(originalData, rollPeriod,
  40     options) {
  41   rollPeriod = Math.min(rollPeriod, originalData.length);
  42   var rollingData = [];
  43
  44   var i, j, y, sum, num_ok;
  45   // Calculate the rolling average for the first rollPeriod - 1 points
  46   // where
  47   // there is not enough data to roll over the full number of points
  48   if (rollPeriod == 1) {
  49     return originalData;
  50   }
  51   for (i = 0; i < originalData.length; i++) {
  52     sum = 0;
  53     num_ok = 0;
  54     for (j = Math.max(0, i - rollPeriod + 1); j < i + 1; j++) {
  55       y = originalData[j][1];
  56       if (y === null || isNaN(y))
  57         continue;
  58       num_ok++;
  59       sum += originalData[j][1];
  60     }
  61     if (num_ok) {
  62       rollingData[i] = [ originalData[i][0], sum / num_ok ];
  63     } else {
  64       rollingData[i] = [ originalData[i][0], null ];
  65     }
  66   }
  67
  68   return rollingData;
  69 };
  70
  71 DefaultHandler.prototype.getExtremeYValues = function(series, dateWindow,
  72     options) {
  73   var minY = null, maxY = null, y;
  74   var firstIdx = 0, lastIdx = series.length - 1;
  75
  76   for ( var j = firstIdx; j <= lastIdx; j++) {
  77     y = series[j][1];
  78     if (y === null || isNaN(y))
  79       continue;
  80     if (maxY === null || y > maxY) {
  81       maxY = y;
  82     }
  83     if (minY === null || y < minY) {
  84       minY = y;
  85     }
  86   }
  87   return [ minY, maxY ];
  88 };
  89
  90 })();