docs: function (property) {
                  var dpi = this.getDpi();
                  switch (this.cfg.PROPERTIES[property].orientation) {
                      case this.cfg.HORIZONTAL :
                          return dpi.x;
                      case this.cfg.VERTICAL :
                          return dpi.y;
                      default : // if composite, then dpi = average
                          return (dpi.x + dpi.y) / 2;
                  }
              }