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