code: public static Point parentToLayer(Layer layer, XY point, Point into) {
      layer.transform().inverseTransform(into.set(point), into);
      into.x += layer.originX();
      into.y += layer.originY();
      return into;
    }
docs: Converts the supplied point from coordinates relative to its parent
  to coordinates relative to the specified layer. The results are stored
  into {@code into}, which is returned for convenience.