<!DOCTYPE HTML> <html> <head> <title>Test overdraw</title> <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script> <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/> </head> <body> <script type="application/javascript"> var domWindowUtils = SpecialPowers.getDOMWindowUtils(window); var overdraw = domWindowUtils.requestCompositorProperty("overdraw"); if (overdraw == -1) { // Overdraw queries are not supported on non OMTC builds. ok(overdraw == -1, "Platform doesn't use a compositor."); } else { // Overdraw may be lower than 100% like on OS X where we don't // composite the window corners. ok(overdraw > 0.95 && overdraw < 200, "Overdraw: " + overdraw); } </script> </body>