test_fixed_bg_scrolling_repaints.html (1538B)
1 <!DOCTYPE HTML> 2 <html> 3 <head> 4 <title>Test that we don't get unnecessary repaints with fixed backgrounds</title> 5 <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script> 6 <script src="chrome://mochikit/content/tests/SimpleTest/paint_listener.js"></script> 7 <link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"/> 8 </head> 9 <!-- Need a timeout here to allow paint unsuppression before we start the test --> 10 <body onload="setTimeout(startTest,0)" style="background:url(blue-32x32.png) top left no-repeat fixed; background-size: 100px 2000px; overflow:hidden;"> 11 <div style="height: 2048px"></div> 12 13 <pre id="test"> 14 <script type="application/javascript"> 15 SimpleTest.waitForExplicitFinish(); 16 17 var utils = window.windowUtils; 18 19 function startTest() { 20 // Do a scroll to ensure we trigger activity heuristics. 21 document.documentElement.scrollTop = 1; 22 waitForAllPaintsFlushed(function () { 23 document.documentElement.scrollTop = 0; 24 waitForAllPaintsFlushed(function () { 25 // Clear paint state and scroll down 26 utils.checkAndClearPaintedState(document.documentElement); 27 document.documentElement.scrollTop = 100; 28 waitForAllPaintsFlushed(function () { 29 // Make sure nothing painted 30 var painted = utils.checkAndClearPaintedState(document.documentElement); 31 is(painted, false, "Fixed background should not have been painted when scrolled"); 32 SimpleTest.finish(); 33 }); 34 }); 35 }); 36 } 37 </script> 38 </pre> 39 </body> 40 </html>