code: function setShape(x, y, w, h) {
           var hW = w / 2;
           var hH = h / 2;
           this.pos.set(x, y);
           this.radius = Math.max(hW, hH);
           this.ratio.set(hW / this.radius, hH / this.radius);
           this.radiusV.set(this.radius, this.radius).scaleV(this.ratio);
           var r = this.radius * this.radius;
           this.radiusSq.set(r, r).scaleV(this.ratio);
           this.updateBounds();
           return this;
         }
docs: set new value to the Ellipse shape
  @name setShape
  @memberOf me.Ellipse.prototype
  @function
  @param {Number} x position of the ellipse
  @param {Number} y position of the ellipse
  @param {Number} w width (diameter) of the ellipse
  @param {Number} h height (diameter) of the ellipse