;;;; sbcl  --noinform --load ex-colors.lisp --no-userinit

(defun idx666 (red green blue) (+ 16 (* red 36) (* green 6) blue))

(defun setpal-code (red green blue)
  (format nil "~C]4;~D;rgb:~2,'0,,X/~2,'0,,X/~2,'0,,X~D\\"
          #\Esc
          (idx666 red green blue)
          (if (zerop red)   0 (+ 55 (* red 40)))
          (if (zerop green) 0 (+ 55 (* green 40)))
          (if (zerop blue)  0 (+ 55 (* blue 40)))
          #\Esc))

(defun build-palette ()
  (dotimes (red 6)
    (dotimes (green 6)
      (dotimes (blue 6)
        (write-string (setpal-code red green blue) *standard-output*)))))

(build-palette)

(format t "System colors:~%")
(dotimes (color 8) (format t "~C[48;5;~Dm  " #\Esc color))  
(format t "~C[0m~%" #\Esc)
(dotimes (color 8) (format t "~C[48;5;~Dm  " #\Esc (+ 8 color)))
(format t "~C[0m~%~%" #\Esc)

(format t "Color cube, 6x6x6:~%")
(dotimes (green 6)
  (dotimes (red 6)
    (dotimes (blue 6)
      (format t "~C[48;5;~Dm  " #\Esc (idx666 red green blue)))
    (format t "~C[0m " #\Esc))
  (terpri))

(format t "Grayscale ramp:~%")
(loop for color from 232 below 256 
      do (format t "~C[48;5;~Dm  " #\Esc color))
(format t "~C[0m~%~%" #\Esc)