auto_tests/tests/stacked.js

   1 /**
   2  * @fileoverview Tests using the "stackedGraph" option.
   3  *
   4  * @author dan@dygraphs.com (Dan Vanderkam)
   5  */
   6 var stackedTestCase = TestCase("stacked");
   7
   8 stackedTestCase.prototype.setUp = function() {
   9   document.body.innerHTML = "<div id='graph'></div>";
  10 };
  11
  12 stackedTestCase.prototype.tearDown = function() {
  13 };
  14
  15 stackedTestCase.prototype.testCorrectColors = function() {
  16   var opts = {
  17     width: 400,
  18     height: 300,
  19     stackedGraph: true,
  20     drawXGrid: false,
  21     drawYGrid: false,
  22     drawXAxis: false,
  23     drawYAxis: false,
  24     valueRange: [0, 3],
  25     colors: ['#00ff00', '#0000ff'],
  26     fillAlpha: 0.15
  27   };
  28   var data = "X,Y1,Y2\n" +
  29       "0,1,1\n" +
  30       "1,1,1\n" +
  31       "2,1,1\n" +
  32       "3,1,1\n"
  33   ;
  34
  35   var graph = document.getElementById("graph");
  36   var g = new Dygraph(graph, data, opts);
  37
  38   // y pixels 299-201 = y2 = transparent blue
  39   // y pixel 200 = y2 line (blue)
  40   // y pixels 199-101 = y1 = transparent green
  41   // y pixel 100 = y1 line (green)
  42   // y pixels 0-99 = nothing (white)
  43
  44   var canvas = g.hidden_ctx_;
  45   var imageData = canvas.getImageData(0, 0, 400, 300);
  46
  47   assertEquals(400, imageData.width);
  48   assertEquals(300, imageData.height);
  49
  50   // returns an (r, g, b, alpha) tuple for the pixel.
  51   // values are in [0, 255].
  52   var getPixel = function(imageData, x, y) {
  53     var i = 4 * (x + imageData.width * y);
  54     var d = imageData.data;
  55     return [d[i], d[i+1], d[i+2], d[i+3]];
  56   };
  57
  58   // 38 = round(0.15 * 255)
  59   assertEquals([0, 0, 255, 38], getPixel(imageData, 200, 250));
  60   assertEquals([0, 255, 0, 38], getPixel(imageData, 200, 150));
  61 };