    # File lib/rvg/embellishable.rb, line 48
                def initialize(rx, ry, cx=0, cy=0)
                    super()
                    rx, ry, cx, cy = Magick::RVG.convert_to_float(rx, ry, cx, cy)
                    if rx < 0 || ry < 0
                        raise ArgumentError, "radii must be >= 0 (#{rx}, #{ry} given)"
                    end
                    @primitive = :ellipse
                    # Ellipses are always complete.
                    @args = [cx, cy, rx, ry, 0, 360]
                end