code: function (o, xp, yp) {
          var x = (o[xp] * rx * cosPhi - o[yp] * ry * sinPhi) + cx;
          var y = (o[xp] * rx * sinPhi + o[yp] * ry * cosPhi) + cy;
          o[xp] = x;
          o[yp] = y;
      }
docs: /* And finally, we transform the poly-bezier approximation of the normalized
  circular arc such that it becomes an approximation of the original
  elliptical arc.
  Scale by the ellipse radii, rotate by the ellipse angle, translate by the ellipse center.