Feature request: allow effects like backdrop-filter, using the current canvas content as the backdrop root

[progers]

Maybe this should work?

<canvas id="canvas" width="200" height="200" layoutsubtree>
  <div id="child" style="width: 100px; height: 100px; backdrop-filter: blur(1px);">
    hello world
  </div>
</canvas>

<script>
  canvas.onpaint = () => {
    const ctx = canvas.getContext('2d');
    ctx.reset();

    // draw stripes
    for (let y = 0; y < canvas.height; y++) {
      ctx.fillStyle = (y % 2 === 0) ? 'black' : 'white';
      ctx.fillRect(0, y, canvas.width, 1);
    }

    // draw #child into the canvas.
    ctx.drawElementImage(child, 50, 50);
  }
  canvas.requestPaint();
</script>