<!DOCTYPE html>
<script src="../../resources/js-test.js"></script>
<script>
description("Tests basic functionalities of offscreenCanvas.getContext on the main thread");
// Tests onstructor of OffscreenCanvas and length/width change
var aCanvas = new OffscreenCanvas(40, 60);
shouldBe("aCanvas.width", "40");
shouldBe("aCanvas.height", "60");
aCanvas.width = 110;
aCanvas.height = 90;
shouldBe("aCanvas.width", "110");
shouldBe("aCanvas.height", "90");
aCanvas.width = 0; // Zero dimension is allowed
shouldBe("aCanvas.width", "0");
// Tests object type of getContext('2d')
var ctx;
shouldNotThrow("ctx = aCanvas.getContext('2d')");
shouldBeType("ctx", "OffscreenCanvasRenderingContext2D");
// Calling getContext on a different context type will return null
var ctx2 = aCanvas.getContext("webgl");
shouldBeNull("ctx2");
// Calling getContext on the same context type will return the original context type
var ctx3 = aCanvas.getContext("2d");
shouldBeNonNull("ctx3");
shouldBeTrue("ctx3 == ctx");
// TODO: change the below part of the test when webgl is supported.
// Calling getContext on an unimplemented context type will return null
var bogusCanvas = new OffscreenCanvas(20, 20);
var bogusCtx = bogusCanvas.getContext("webgl");
shouldBeNull("bogusCtx");
</script>