constructor(ancestor) {
		// parent constructor
		super();

		/**
		 * a reference to the parent object that contains this TextMetrics object
		 * @type {Renderable}
		 * @default undefined
		 */
		this.ancestor = ancestor;

		this.setMinMax(0, 0, 0, 0);
	}
@param {Text|BitmapText} ancestor - the parent object that contains this TextMetrics object