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);
  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);
  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   assertTrue(selector.length > 0);
  66   $.each(selector, function(idx, child) {
  67     assertEquals(expectedValue,  $(child).css(property));
  68   });
  69 };
  70
  71
  72 /**
  73  * Takes in an array of strings and returns an array of floats.
  74  */
  75 Util.makeNumbers = function(ary) {
  76   var ret = [];
  77   for (var i = 0; i < ary.length; i++) {
  78     ret.push(parseFloat(ary[i]));
  79   }
  80   return ret;
  81 };
  82
  83
  84 /**
  85  * Sample a pixel from the canvas.
  86  * Returns an [r, g, b, a] tuple where each values is in [0, 255].
  87  */
  88 Util.samplePixel = function(canvas, x, y) {
  89   var ctx = canvas.getContext("2d");  // bypasses Proxy if applied.
  90
  91   // TODO(danvk): Any performance issues with this?
  92   var imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
  93
  94   var i = 4 * (x + imageData.width * y);
  95   var d = imageData.data;
  96   return [d[i], d[i+1], d[i+2], d[i+3]];
  97 };