(multiple-value-bind (h sa v) (dufy:rgb-to-hsv (/ r 255.0)
                                                     (/ g 255.0)
                                                     (/ b 255.0))

      (multiple-value-bind (h sa v) (dufy:qrgb-to-hsv r g b)

                       (/ h 360.0) sa v)

                       h sa v)
          (unless (null s)
            (format s "~%")))))))
(defun hsl-color (name &optional (s t))
  (let ((values (theme-color name)))
    (destructuring-bind (r g b) values
      (multiple-value-bind (h sa l) (dufy:qrgb-to-hsl r g b)
        (prog1 (format s
                       "hsl(~,3f, ~,3f%, ~,3f%)"
                       h (* 100.0 sa) (* 100.0 l))

                        (image-size nil image-size-p)

                                "gnuplot -e \"~:[~*~;set xrange [~{~f~^:~}];~]~:[~*~;set yrange [~{~f~^:~}];~]set terminal svg font 'Alegreya,14' enhanced  background '~a'; set border lw 3 lc rgb '~a'; plot '< cat' lt rgb '~a' notitle ~:[~;with linespoint~]\""

                                "gnuplot -e \"~:[~*~;set xrange [~{~f~^:~}];~]~:[~*~;set yrange [~{~f~^:~}];~]set terminal svg font 'Alegreya,14' enhanced ~:[~*~;size ~{~a~^,~} ~]background '~a'; set border lw 3 lc rgb '~a'; set logscale y 2; plot '< cat' lt rgb '~a' notitle ~:[~;with linespoint~]\""

                                image-size-p image-size