OffscreenCanvasImageRenderingAuto.html

<!doctype html>
<html>
  <head>
    <title>Test if the users can change Image Rendering Quality in Offscreen Canvas</title>
    <style type="text/css">
#can {
  width: 500px;
  height: 500px;
  image-rendering: pixelated;
}
    </style>
  </head>
  <body>
  <canvas id="can" width="50" height="50"></canvas>
  <script>
const c2 = document.getElementById("can");
const offscreen_canvas = c2.transferControlToOffscreen();
const ctx_o = offscreen_canvas.getContext('2d');

c2.style.imageRendering = "auto";

ctx_o.clearRect(0, 0, 50, 50);
ctx_o.fillRect(10, 10, 30, 30);

function waitForCanvasToDraw() {
  return new Promise(resolve => {
    const testPixel = function() {
      const d = ctx_o.getImageData(20, 20, 1, 1);
      if (d.data[0] == 0 && d.data[3] == 255) {
        setTimeout(resolve, 2000);
      } else {
        requestAnimationFrame(testPixel);
      }
    }
    testPixel();
  })
}

if (window.testRunner) {
  testRunner.waitUntilDone();
}
waitForCanvasToDraw().then(() => {
  if (window.testRunner) {
    testRunner.notifyDone();
  }
}).catch(err => {
  testRunner.notifyDone();
  throw err;
});

</script>
</body>
</html>

chromium/third_party/blink/web_tests/virtual/gpu/fast/canvas/OffscreenCanvasImageRenderingAuto.html