    paper.paperToLocalPoint(p)

Transform the point `p` defined in the paper coordinate system to the local coordinate system.

    var paperCenter = g.Point(paper.options.width / 2, paper.options.height / 2);
    var localPoint1 = paper.paperToLocalPoint(paperCenter);
     // alternative method signature
    var localPoint2 = paper.paperToLocalPoint(paper.options.width / 2, paper.options.height / 2);
    // Move the element to the center of the paper viewport.
    var elSize = element.size();
    element.position(localPoint1.x - elSize.width, localPoint1.y - elSize.height);