dom/canvas/test/test_drawSnapshot_fixed.html

   1 <!DOCTYPE HTML>
   2 <html>
   3 <head>
   4   <meta charset="utf-8">
   5   <title>Test for drawSnapshot</title>
   6   <script src="/tests/SimpleTest/SimpleTest.js"></script>
   7   <script src="/tests/SimpleTest/WindowSnapshot.js"></script>
   8   <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
   9   <style>
  10     html {
  11       height: 2000px;
  12       overflow: hidden;
  13     }
  14     header {
  15       position: fixed;
  16       background: red;
  17       display: block;
  18       left: 0;
  19       right: 0;
  20       top: 0;
  21       height: 200px;
  22     }
  23   </style>
  24   <script type="application/javascript">
  25   function make_canvas() {
  26     var canvas = document.createElement("canvas");
  27     canvas.setAttribute("height", 2000);
  28     canvas.setAttribute("width", 500);
  29     return canvas;
  30   }
  31
  32   SimpleTest.waitForExplicitFinish();
  33   window.addEventListener("load", runTests);
  34
  35   window.scrollTo(0, 1000);
  36
  37   async function runTests(event) {
  38     var testCanvas = make_canvas();
  39     var testCx = testCanvas.getContext("2d");
  40     var testWrapCx = SpecialPowers.wrap(testCx);
  41
  42     // Take a snapshot of the page while scrolled down, so that the fixed header will
  43     // be visually in the middle of the root scroll frame, but should still be at the
  44     // top of the snapshot (since snapshots with a rect are taken relative to the document).
  45     var rect = new window.DOMRect(0, 0, 500, 2000);
  46     let image = await SpecialPowers.snapshotContext(window, rect, "rgb(255, 255, 255)", true);
  47     testWrapCx.drawImage(image, 0, 0);
  48
  49     var refCanvas = make_canvas();
  50     var refCx = refCanvas.getContext("2d");
  51
  52     // Construct a reference image with an equivalent red square at the top.
  53     refCx.fillStyle = "white";
  54     refCx.fillRect(0, 0, 500, 2000);
  55     refCx.fillStyle = "red";
  56     refCx.fillRect(0, 0, 500, 200);
  57
  58     assertSnapshots(testCanvas, refCanvas, true, null, "position:fixed element with scrolling", "reference");
  59
  60     SimpleTest.finish();
  61   }
  62
  63   </script>
  64 </head>
  65 <body>
  66   <header></header>
  67 </body>
  68 </html>