<!DOCTYPE HTML> <html> <head> <title>OffscreenCanvas: Test neutering</title> <script src="/tests/SimpleTest/SimpleTest.js"></script> <link rel="stylesheet" href="/tests/SimpleTest/test.css"> </head> <body> <canvas id="c" width="64" height="64"></canvas> <script> SimpleTest.waitForExplicitFinish(); function runTest() { var htmlCanvas = document.getElementById("c"); var worker = new Worker("offscreencanvas_neuter.js"); ok(htmlCanvas, "Should have HTML canvas element"); ok(worker, "Web worker successfully created"); ok(htmlCanvas.transferControlToOffscreen, "HTMLCanvasElement has transferControlToOffscreen function"); var offscreenCanvas = htmlCanvas.transferControlToOffscreen(); ok(offscreenCanvas, "Expected transferControlToOffscreen to succeed"); /* check html canvas is neuterd */ is(htmlCanvas.width, 64, "HTML canvas has correct width"); SimpleTest.doesThrow( function() { htmlCanvas.width = 128; }, "Can't change html canvas' width after transferControlToOffscreen"); SimpleTest.doesThrow( function() { htmlCanvas.height = 128; }, "Can't change html canvas' height after transferControlToOffscreen"); ok(!htmlCanvas.getContext("2d"), "Can't getContext after transferControlToOffscreen"); ok(!htmlCanvas.getContext("webgl"), "Can't getContext after transferControlToOffscreen"); ok(!htmlCanvas.getContext("webgl2"), "Can't getContext after transferControlToOffscreen"); worker.postMessage(offscreenCanvas, [offscreenCanvas]); /* check parent offscreencanvas is neutered after being transfered */ SimpleTest.doesThrow( function() { offscreenCanvas.width = 128; }, "Can't change transfered worker canvas width"); SimpleTest.doesThrow( function() { offscreenCanvas.height = 128; }, "Can't change transfered worker canvas height"); SimpleTest.doesThrow( function() { offscreenCanvas.getContext("2d") }, "Can't getContext on transfered worker canvas"); SimpleTest.doesThrow( function() { offscreenCanvas.getContext("webgl") }, "Can't getContext on transfered worker canvas"); SimpleTest.doesThrow( function() { offscreenCanvas.getContext("webgl2") }, "Can't getContext on transfered worker canvas"); // Transfer a neutered offscreencanvas should be ok. worker.postMessage(offscreenCanvas, [offscreenCanvas]); worker.terminate(); SimpleTest.finish(); } SpecialPowers.pushPrefEnv({'set': [ ['gfx.offscreencanvas.enabled', true], ['webgl.force-enabled', true], ]}, runTest); </script> </body> </html>