;;; colorcomp.el
;;;
;;; Copyright (C) 2006, 2007, 2008 Thien-Thi Nguyen
;;;
;;; This file is part of ttn's personal elisp library, released under
;;; the terms of the GNU General Public License as published by the
;;; Free Software Foundation; either version 3, or (at your option) any
;;; later version.  There is NO WARRANTY.  See file COPYING for details.
;;;
;;; Description: Manipulate color components interactively.

(require 'ewoc)

;; vars

(defvar colorcomp-ewoc nil)
(defvar colorcomp-data nil)

(defvar colorcomp-labels ["Red" "Green" "Blue"])

(defvar colorcomp-mode-map nil)

;; funcs

(defun colorcomp-pp (data)
  (if data
      (let ((comp (aref colorcomp-data data)))
        (insert (aref colorcomp-labels data) "\t: #x"
                (format "%02X" comp) " "
                (make-string (ash comp -2) ?#) "\n"))
    (let ((cstr (format "#%02X%02X%02X"
                        (aref colorcomp-data 0)
                        (aref colorcomp-data 1)
                        (aref colorcomp-data 2)))
          (samp " (sample text) "))
      (insert "Color\t: "
              (propertize samp 'face `(foreground-color . ,cstr))
              (propertize samp 'face `(background-color . ,cstr))
              "\n"))))

;;;###autoload
(defun colorcomp (color)
  "Allow fiddling with COLOR in a new buffer.
The buffer is in Color Components mode."
  (interactive "sColor (name or #RGB or #RRGGBB): ")
  (when (string= "" color)
    (setq color "green"))
  (unless (color-values color)
    (error "No such color: %S" color))
  (switch-to-buffer
   (generate-new-buffer (format "originally: %s" color)))
  (kill-all-local-variables)
  (setq major-mode 'colorcomp-mode
        mode-name "Color Components")
  (use-local-map colorcomp-mode-map)
  (erase-buffer)
  (buffer-disable-undo)
  (let ((data (apply 'vector (mapcar (lambda (n) (ash n -8))
                                     (color-values color))))
        (ewoc (ewoc-create 'colorcomp-pp
                           "\nColor Components\n\n"
                           (substitute-command-keys
                            "\n\\{colorcomp-mode-map}"))))
    (set (make-local-variable 'colorcomp-data) data)
    (set (make-local-variable 'colorcomp-ewoc) ewoc)
    (ewoc-enter-last ewoc 0)
    (ewoc-enter-last ewoc 1)
    (ewoc-enter-last ewoc 2)
    (ewoc-enter-last ewoc nil)))

(defun colorcomp-mod (index limit delta)
  (let ((cur (aref colorcomp-data index))
        (ewoc colorcomp-ewoc))
    (unless (= limit cur)
      (aset colorcomp-data index (+ cur delta)))
    (ewoc-invalidate
     ewoc
     (ewoc-nth ewoc index)
     (ewoc-nth ewoc -1))
    (sit-for 0)))

(defun colorcomp-R-more () (interactive) (colorcomp-mod 0 255 1))
(defun colorcomp-G-more () (interactive) (colorcomp-mod 1 255 1))
(defun colorcomp-B-more () (interactive) (colorcomp-mod 2 255 1))
(defun colorcomp-R-less () (interactive) (colorcomp-mod 0 0 -1))
(defun colorcomp-G-less () (interactive) (colorcomp-mod 1 0 -1))
(defun colorcomp-B-less () (interactive) (colorcomp-mod 2 0 -1))

(defun colorcomp-copy-as-kill-and-exit ()
  "Copy the color components into the kill ring and kill the buffer.
The string is formatted #RRGGBB (hash followed by six hex digits)."
  (interactive)
  (kill-new (format "#%02X%02X%02X"
                    (aref colorcomp-data 0)
                    (aref colorcomp-data 1)
                    (aref colorcomp-data 2)))
  (kill-buffer nil))

;; load-time actions

(unless colorcomp-mode-map
  (setq colorcomp-mode-map
        (let ((m (make-sparse-keymap)))
          (suppress-keymap m)
          (define-key m "i" 'colorcomp-R-less)
          (define-key m "o" 'colorcomp-R-more)
          (define-key m "k" 'colorcomp-G-less)
          (define-key m "l" 'colorcomp-G-more)
          (define-key m "," 'colorcomp-B-less)
          (define-key m "." 'colorcomp-B-more)
          (define-key m " " 'colorcomp-copy-as-kill-and-exit)
          m)))

(provide 'colorcomp)

;;; colorcomp.el ends here