third_party/WebKit/LayoutTests/fast/dom/Window/device-pixel-ratio-on-zoom.html

   1 <!DOCTYPE html>
   2 <html>
   3     <head>
   4         <script src="../../../resources/js-test.js"></script>
   5     </head>
   6     <body>
   7         <p>
   8             Tests that window.devicePixelRatio is updated on zoom.
   9         </p>
  10         <script>
  11             // eventSender.zoomPageOut/In zooms with a fixed factor of 1.2 instead
  12             // of the zoom levels of the actual browser.
  13             var ZOOM_MULTIPLIER = 1.2;
  14
  15             function round(n)
  16             {
  17                 return Math.round(n * 100) / 100;
  18             }
  19
  20             var expectedRatio = window.devicePixelRatio;
  21             if (window.eventSender) {
  22                 for (var i = 0; i < 5; i++) {
  23                     eventSender.zoomPageOut();
  24                     expectedRatio /= ZOOM_MULTIPLIER;
  25                     shouldBe('round(window.devicePixelRatio)', String(round(expectedRatio)));
  26                 }
  27                 for (var i = 0; i < 10; i++) {
  28                     eventSender.zoomPageIn();
  29                     expectedRatio *= ZOOM_MULTIPLIER;
  30                     shouldBe('round(window.devicePixelRatio)', String(round(expectedRatio)));
  31                 }
  32             }
  33         </script>
  34     </body>
  35 </html>