auto_tests/tests/hidpi.js

   1 /**
   2  * @fileoverview Tests for window.devicePixelRatio > 1.
   3  *
   4  * @author danvdk@gmail.com (Dan Vanderkam)
   5  */
   6
   7 import Dygraph from '../../src/dygraph';
   8
   9 describe("hidpi", function() {
  10
  11 cleanupAfterEach();
  12
  13 var savePixelRatio;
  14 beforeEach(function() {
  15   savePixelRatio = window.devicePixelRatio;
  16   window.devicePixelRatio = 2;
  17 });
  18
  19 afterEach(function() {
  20   window.devicePixelRatio = savePixelRatio;
  21 });
  22
  23 it('testDoesntCreateScrollbars', function() {
  24   var sw = document.body.scrollWidth;
  25   var cw = document.body.clientWidth;
  26
  27   var graph = document.getElementById("graph");
  28   graph.style.width = "70%";  // more than half.
  29   graph.style.height = "200px";
  30
  31   var opts = {};
  32   var data = "X,Y\n" +
  33       "0,-1\n" +
  34       "1,0\n" +
  35       "2,1\n" +
  36       "3,0\n"
  37   ;
  38
  39   var g = new Dygraph(graph, data, opts);
  40
  41   // Adding the graph shouldn't cause the width of the page to change.
  42   // (essentially, we're checking that we don't end up with a scrollbar)
  43   // See http://stackoverflow.com/a/2146905/388951
  44   assert.equal(cw, document.body.clientWidth);
  45   assert.equal(sw, document.body.scrollWidth);
  46 });
  47
  48 it('should be influenced by options.pixelRatio', function () {
  49   var graph = document.getElementById("graph");
  50
  51   // make sure devicePixelRatio is still setup to not 1.
  52   assert(devicePixelRatio > 1.5, 'devicePixelRatio is not much greater than 1.');
  53
  54   var data = "X,Y\n" +
  55     "0,-1\n" +
  56     "1,0\n" +
  57     "2,1\n" +
  58     "3,0\n";
  59
  60   // first try a default one
  61   var g1 = new Dygraph(graph, data, {});
  62   var area1 = g1.getArea();
  63
  64   var g2 = new Dygraph(graph, data, { pixelRatio: 1 });
  65   var area2 = g2.getArea();
  66
  67   var g3 = new Dygraph(graph, data, { pixelRatio: 3 });
  68   var area3 = g3.getArea();
  69
  70   assert.deepEqual(area1, area2, 'areas 1 and 2 are not the same');
  71   assert.deepEqual(area2, area3, 'areas 2 and 3 are not the same');
  72
  73   assert.notEqual(g1.canvas_.width, g2.canvas_.width,
  74     'Expected, for devicePixelRatio != 1, '
  75     + 'that setting options.pixelRatio would change the canvas width');
  76   assert.equal(g2.canvas_.width * 3, g3.canvas_.width,
  77     'Expected that pixelRatio of 3 vs 1 would triple the canvas width.');
  78 });
  79
  80 });