docs: function getNormalizedEventCoords(ev, pageOffset, clientRect) {
    const { x, y } = pageOffset;
    const documentX = x + clientRect.left;
    const documentY = y + clientRect.top;
  
    let normalizedX;
    let normalizedY;
    // Determine touch point relative to the ripple container.
    if (ev.type === 'touchstart') {
      normalizedX = ev.changedTouches[0].pageX - documentX;
      normalizedY = ev.changedTouches[0].pageY - documentY;
    } else {
      normalizedX = ev.pageX - documentX;
      normalizedY = ev.pageY - documentY;
    }
  
    return { x: normalizedX, y: normalizedY };
  }