function getPointerPosition(el, event) {
  var position = {};
  var box = findPosition(el);
  var boxW = el.offsetWidth;
  var boxH = el.offsetHeight;

  var boxY = box.top;
  var boxX = box.left;
  var pageY = event.pageY;
  var pageX = event.pageX;

  if (event.changedTouches) {
    pageX = event.changedTouches[0].pageX;
    pageY = event.changedTouches[0].pageY;
  }

  position.y = Math.max(0, Math.min(1, (boxY - pageY + boxH) / boxH));
  position.x = Math.max(0, Math.min(1, (pageX - boxX) / boxW));

  return position;
}