Hex color to RGBA conversion

hex-to-rgba.el

(defun dotspacemacs/user-config ()
  "Configuration for user code:
This function is called at the very end of Spacemacs startup, after layer
configuration.
Put your configuration code here, except for variables that should be set
before packages are loaded."
  (defun hex-to-list (hex)
    (mapcar (lambda (z)
              (number-to-string (string-to-number z 16)))
            (mapcar (lambda (y)
                      (substring hex (car y) (car (last y))))
                    (mapcar (lambda (x)
                              (list (* 2 (1- x)) (+ (* 2 (1- x)) 2))) (number-sequence 1 3)))))

  (defun rgba-from-input (color)
    (interactive "S")
    (message "%s" color)
    )

  (defun hex-color-to-rgba (start end)
    "Converts a color expressed in hexadecimal into its RGBA representation"
    (interactive "r")
    (when (region-active-p)
      (let* ((region (buffer-substring start end))
             (color (if (char-equal ?# (string-to-char region)) (substring region 1) region))
             (len (length color))
             (rgb (hex-to-list (apply 'concat (mapcar (lambda (c) (concat c c)) (split-string color "")))))
             (save-excursion
               (save-restriction
                 (narrow-to-region start end)
                 (delete-region start end)
                 (insert (format "rgba(%s1)" (apply 'concat (mapcar (lambda (x) (concat x ", ")) rgb))))
                 ))
             )
        )
      ))
  )