# File lib/rvg/transformable.rb, line 71
        def scale(sx, sy=nil)
            sy ||= sx
            begin
                @transforms << [:scale, [Float(sx), Float(sy)]]
            rescue ArgumentError
                raise ArgumentError, "arguments must be convertable to float (got #{sx.class}, #{sy.class})"
            end
            yield(self) if block_given?
            self
        end