let draw =
  () {
    case Dom.Canvas.fromDomElement(canvas) {
      Maybe::Just(el) =>
        case image {
          Maybe::Just(img) =>
            {
              let dims =
                Dom.getDimensions(img)
              // resize canvas to display full image
              Dom.setStyle(img, "display", "none")
              el
              |> Dom.Canvas.toDomElement
              |> Dom.setAttribute("width", "#{dims.width}")
              |> Dom.setAttribute("height", "#{dims.width}")
              let imageData =
                CanvasImageSource.fromImage(img)
              el
              |> Canvas.drawImage(imageData, 0, 0)
              ""
            }
          =>
            ""
        }
      =>
        ""
    }
  }
<>
  <img as image
    src={@asset(../../assets/rhino.jpg)}
    onLoad={draw}/>
  <canvas as canvas/>
</>