let polarToCartesian centerX centerY radius angleInDegrees =
  let angleInRadians = (angleInDegrees -. 90.0) *. Js.Math._PI /. 180.0 in
  ( centerX +. (radius *. Js.Math.cos angleInRadians),
    centerY +. (radius *. Js.Math.sin angleInRadians) )

let describe x y radius startAngle endAngle =
  let startX, startY = polarToCartesian x y radius endAngle in
  let endX, endY = polarToCartesian x y radius startAngle in
  let largeArcFlag = if endAngle -. startAngle <= 180.0 then "0" else "1" in
  [|
    "M";
    Js.Float.toString startX;
    Js.Float.toString startY;
    "A";
    Js.Float.toString radius;
    Js.Float.toString radius;
    "0";
    largeArcFlag;
    "0";
    Js.Float.toString endX;
    Js.Float.toString endY;
  |]
  |> Js.Array.joinWith " "