src/datahandler/bars-custom.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 custom bars option.
   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.DataHandlers.BarsHandler
  20  */
  21 Dygraph.DataHandlers.CustomBarsHandler = function() {
  22 };
  23
  24 var CustomBarsHandler = Dygraph.DataHandlers.CustomBarsHandler;
  25 CustomBarsHandler.prototype = new Dygraph.DataHandlers.BarsHandler();
  26
  27 /** @inheritDoc */
  28 CustomBarsHandler.prototype.extractSeries = function(rawData, i, options) {
  29   // TODO(danvk): pre-allocate series here.
  30   var series = [];
  31   var x, y, point;
  32   var logScale = options.get('logscale');
  33   for ( var j = 0; j < rawData.length; j++) {
  34     x = rawData[j][0];
  35     point = rawData[j][i];
  36     if (logScale && point !== null) {
  37       // On the log scale, points less than zero do not exist.
  38       // This will create a gap in the chart.
  39       if (point[0] <= 0 || point[1] <= 0 || point[2] <= 0) {
  40         point = null;
  41       }
  42     }
  43     // Extract to the unified data format.
  44     if (point !== null) {
  45       y = point[1];
  46       if (y !== null && !isNaN(y)) {
  47         series.push([ x, y, [ point[0], point[2] ] ]);
  48       } else {
  49         series.push([ x, y, [ y, y ] ]);
  50       }
  51     } else {
  52       series.push([ x, null, [ null, null ] ]);
  53     }
  54   }
  55   return series;
  56 };
  57
  58 /** @inheritDoc */
  59 CustomBarsHandler.prototype.rollingAverage =
  60     function(originalData, rollPeriod, options) {
  61   rollPeriod = Math.min(rollPeriod, originalData.length);
  62   var rollingData = [];
  63   var y, low, high, mid,count, i, extremes;
  64
  65   low = 0;
  66   mid = 0;
  67   high = 0;
  68   count = 0;
  69   for (i = 0; i < originalData.length; i++) {
  70     y = originalData[i][1];
  71     extremes = originalData[i][2];
  72     rollingData[i] = originalData[i];
  73
  74     if (y !== null && !isNaN(y)) {
  75       low += extremes[0];
  76       mid += y;
  77       high += extremes[1];
  78       count += 1;
  79     }
  80     if (i - rollPeriod >= 0) {
  81       var prev = originalData[i - rollPeriod];
  82       if (prev[1] !== null && !isNaN(prev[1])) {
  83         low -= prev[2][0];
  84         mid -= prev[1];
  85         high -= prev[2][1];
  86         count -= 1;
  87       }
  88     }
  89     if (count) {
  90       rollingData[i] = [
  91           originalData[i][0],
  92           1.0 * mid / count,
  93           [ 1.0 * low / count,
  94             1.0 * high / count ] ];
  95     } else {
  96       rollingData[i] = [ originalData[i][0], null, [ null, null ] ];
  97     }
  98   }
  99
 100   return rollingData;
 101 };
 102
 103 })();