auto_tests/tests/Util.js

   1 /**
   2  * @fileoverview Utility functions for Dygraphs.
   3  *
   4  * @author konigsberg@google.com (Robert Konigsberg)
   5  */
   6 var Util = {};
   7
   8 /**
   9  * Get the y-labels for a given axis.
  10  *
  11  * You can specify a parent if more than one graph is in the document.
  12  */
  13 Util.getYLabels = function(axis_num, parent) {
  14   axis_num = axis_num || "";
  15   parent = parent || document;
  16   var y_labels = parent.getElementsByClassName("dygraph-axis-label-y" + axis_num);
  17   var ary = [];
  18   for (var i = 0; i < y_labels.length; i++) {
  19     ary.push(y_labels[i].innerHTML.replace(/&#160;|&nbsp;/g, ' '));
  20   }
  21   return ary;
  22 };
  23
  24 /**
  25  * Get the x-labels for a given axis.
  26  *
  27  * You can specify a parent if more than one graph is in the document.
  28  */
  29 Util.getXLabels = function(parent) {
  30   parent = parent || document;
  31   var x_labels = parent.getElementsByClassName("dygraph-axis-label-x");
  32   var ary = [];
  33   for (var i = 0; i < x_labels.length; i++) {
  34     ary.push(x_labels[i].innerHTML.replace(/&#160;|&nbsp;/g, ' '));
  35   }
  36   return ary;
  37 };
  38
  39 /**
  40  * Returns all text in tags w/ a given css class, sorted.
  41  * You can specify a parent if more than one graph is on the document.
  42  */
  43 Util.getClassTexts = function(css_class, parent) {
  44   parent = parent || document;
  45   var texts = [];
  46   var els = parent.getElementsByClassName(css_class);
  47   for (var i = 0; i < els.length; i++) {
  48     texts[i] = els[i].textContent;
  49   }
  50   texts.sort();
  51   return texts;
  52 };
  53
  54 Util.getLegend = function(parent) {
  55   parent = parent || document;
  56   var legend = parent.getElementsByClassName("dygraph-legend")[0];
  57   var re = new RegExp(String.fromCharCode(160), 'g');
  58   return legend.textContent.replace(re, ' ');
  59 };
  60
  61 /**
  62  * Assert that all elements have a certain style property.
  63  */
  64 Util.assertStyleOfChildren = function(selector, property, expectedValue) {
  65   assert.isTrue(selector.length > 0);
  66   for (var idx = 0; idx < selector.length; idx++) {
  67     var child = selector[idx];
  68     assert.equal(expectedValue, window.getComputedStyle(child)[property]);
  69   }
  70 };
  71
  72
  73 /**
  74  * Takes in an array of strings and returns an array of floats.
  75  */
  76 Util.makeNumbers = function(ary) {
  77   var ret = [];
  78   for (var i = 0; i < ary.length; i++) {
  79     ret.push(parseFloat(ary[i]));
  80   }
  81   return ret;
  82 };
  83
  84
  85 /**
  86  * Sample a pixel from the canvas.
  87  * Returns an [r, g, b, a] tuple where each values is in [0, 255].
  88  */
  89 Util.samplePixel = function(canvas, x, y) {
  90   var ctx = canvas.getContext("2d");  // bypasses Proxy if applied.
  91
  92   // TODO(danvk): Any performance issues with this?
  93   var imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
  94
  95   var scale = Dygraph.getContextPixelRatio(ctx);
  96
  97   var i = 4 * (x * scale + imageData.width * y * scale);
  98   var d = imageData.data;
  99   return [d[i], d[i+1], d[i+2], d[i+3]];
 100 };
 101
 102 /**
 103  * Overrides the browser's built-in XMLHttpRequest with a mock.
 104  * Usage:
 105  *
 106  * var mockXhr = Util.overrideXMLHttpRequest(your_data);
 107  * ... call code that does an XHR ...
 108  * mockXhr.respond();  // restores default behavior.
 109  * ... do your assertions ...
 110  */
 111 Util.overrideXMLHttpRequest = function(data) {
 112   var originalXMLHttpRequest = XMLHttpRequest;
 113
 114   var requests = [];
 115   var FakeXMLHttpRequest = function () {
 116     requests.push(this);
 117   };
 118   FakeXMLHttpRequest.prototype.open = function () {};
 119   FakeXMLHttpRequest.prototype.send = function () {
 120     this.readyState = 4;
 121     this.status = 200;
 122     this.responseText = data;
 123   };
 124   FakeXMLHttpRequest.restore = function() {
 125     window.XMLHttpRequest = originalXMLHttpRequest;
 126   };
 127   FakeXMLHttpRequest.respond = function() {
 128     for (var i = 0; i < requests.length; i++) {
 129       requests[i].onreadystatechange();
 130     }
 131     FakeXMLHttpRequest.restore();
 132   };
 133   window.XMLHttpRequest = FakeXMLHttpRequest;
 134   return FakeXMLHttpRequest;
 135 };
 136
 137 /**
 138  * Format a date as 2000/01/23
 139  * @param {number} dateMillis Millis since epoch.
 140  * @return {string} The date formatted as YYYY-MM-DD.
 141  */
 142 Util.formatDate = function(dateMillis) {
 143   return Dygraph.dateString_(dateMillis).slice(0, 10);  // 10 == "YYYY/MM/DD".length
 144 };