origin(newValue) {
    return this._backCompatOption('origin', newValue);
  }
Gets or sets the origin of the Interactable's element.  The x and y
of the origin will be subtracted from action event coordinates.

@param {Element | object | string} [origin] An HTML or SVG Element whose
rect will be used, an object eg. { x: 0, y: 0 } or string 'parent', 'self'
or any CSS selector

@return {object} The current origin or this Interactable