class Magick::Draw

def stroke_dasharray(*list)

Specify a stroke dash pattern 
def stroke_dasharray(*list)
    if list.length == 0
        primitive "stroke-dasharray none"
    else
        list.each { |x|
            if x <= 0 then
                Kernel.raise ArgumentError, "dash array elements must be > 0 (#{x} given)"
            end
        }
        primitive "stroke-dasharray #{list.join(',')}"
    end
end