# File lib/rvg/embellishable.rb, line 30
            def initialize(r, cx=0, cy=0)
                super()
                r, cx, cy = Magick::RVG.convert_to_float(r, cx, cy)
                if r < 0
                    raise ArgumentError, "radius must be >= 0 (#{r} given)"
                end
                @primitive = :circle
                @args = [cx, cy, cx+r, cy]
                self
            end