<!DOCTYPE html>
<html>
<body>
<canvas id='output' width='200' height='200'></canvas>
<script id='myWorker' type='text/worker'>
self.onmessage = function(e) {
var aCanvas = new OffscreenCanvas(200, 200);
var ctx = aCanvas.getContext('2d');
var radialGrad = ctx.createRadialGradient(100, 100, 100, 100, 100, 0);
radialGrad.addColorStop(0, "#fff");
radialGrad.addColorStop(1, "#0f0");
ctx.fillStyle = radialGrad;
ctx.fillRect(0, 0, 200, 200);
var linearGrad = ctx.createLinearGradient(0, 0, 200, 200);
linearGrad.addColorStop(0, "#f00");
linearGrad.addColorStop(1, "#ff0");
ctx.strokeStyle = linearGrad;
ctx.lineWidth = "3";
ctx.beginPath();
ctx.moveTo(0, 0);
ctx.lineTo(200, 200);
ctx.stroke();
var image = aCanvas.transferToImageBitmap();
self.postMessage(image, [image]);
};
</script>
<script>
if (window.testRunner) {
testRunner.waitUntilDone();
}
var blob = new Blob([document.getElementById('myWorker').textContent]);
var worker = new Worker(URL.createObjectURL(blob));
worker.addEventListener('message', msg => {
var outputCtx = document.getElementById('output').getContext('bitmaprenderer');
outputCtx.transferFromImageBitmap(msg.data);
if (window.testRunner) {
testRunner.notifyDone();
}
});
worker.postMessage("");
</script>
</body>