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 // Convert &nbsp; to a normal space
  55 Util.nbspToSpace = function(str) {
  56   var re = new RegExp(String.fromCharCode(160), 'g');
  57   return str.replace(re, ' ');
  58 };
  59
  60 Util.getLegend = function(parent) {
  61   parent = parent || document;
  62   var legend = parent.getElementsByClassName("dygraph-legend")[0];
  63   return Util.nbspToSpace(legend.textContent);
  64 };
  65
  66 /**
  67  * Assert that all elements have a certain style property.
  68  */
  69 Util.assertStyleOfChildren = function(selector, property, expectedValue) {
  70   assert.isTrue(selector.length > 0);
  71   for (var idx = 0; idx < selector.length; idx++) {
  72     var child = selector[idx];
  73     assert.equal(expectedValue, window.getComputedStyle(child)[property]);
  74   }
  75 };
  76
  77
  78 /**
  79  * Takes in an array of strings and returns an array of floats.
  80  */
  81 Util.makeNumbers = function(ary) {
  82   var ret = [];
  83   for (var i = 0; i < ary.length; i++) {
  84     ret.push(parseFloat(ary[i]));
  85   }
  86   return ret;
  87 };
  88
  89
  90 /**
  91  * Sample a pixel from the canvas.
  92  * Returns an [r, g, b, a] tuple where each values is in [0, 255].
  93  */
  94 Util.samplePixel = function(canvas, x, y) {
  95   var ctx = canvas.getContext("2d");  // bypasses Proxy if applied.
  96
  97   // TODO(danvk): Any performance issues with this?
  98   var imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
  99
 100   var scale = Dygraph.getContextPixelRatio(ctx);
 101
 102   var i = 4 * (x * scale + imageData.width * y * scale);
 103   var d = imageData.data;
 104   return [d[i], d[i+1], d[i+2], d[i+3]];
 105 };
 106
 107 /**
 108  * Overrides the browser's built-in XMLHttpRequest with a mock.
 109  * Usage:
 110  *
 111  * var mockXhr = Util.overrideXMLHttpRequest(your_data);
 112  * ... call code that does an XHR ...
 113  * mockXhr.respond();  // restores default behavior.
 114  * ... do your assertions ...
 115  */
 116 Util.overrideXMLHttpRequest = function(data) {
 117   var originalXMLHttpRequest = XMLHttpRequest;
 118
 119   var requests = [];
 120   var FakeXMLHttpRequest = function () {
 121     requests.push(this);
 122   };
 123   FakeXMLHttpRequest.prototype.open = function () {};
 124   FakeXMLHttpRequest.prototype.send = function () {
 125     this.readyState = 4;
 126     this.status = 200;
 127     this.responseText = data;
 128   };
 129   FakeXMLHttpRequest.restore = function() {
 130     window.XMLHttpRequest = originalXMLHttpRequest;
 131   };
 132   FakeXMLHttpRequest.respond = function() {
 133     for (var i = 0; i < requests.length; i++) {
 134       requests[i].onreadystatechange();
 135     }
 136     FakeXMLHttpRequest.restore();
 137   };
 138   window.XMLHttpRequest = FakeXMLHttpRequest;
 139   return FakeXMLHttpRequest;
 140 };
 141
 142 /**
 143  * Format a date as 2000/01/23
 144  * @param {number} dateMillis Millis since epoch.
 145  * @return {string} The date formatted as YYYY-MM-DD.
 146  */
 147 Util.formatDate = function(dateMillis) {
 148   return Dygraph.dateString_(dateMillis).slice(0, 10);  // 10 == "YYYY/MM/DD".length
 149 };