+;;; sixel.el --- minor mode for processing sixel graphics
+
+;; Copyright (C) 2019 Tim Vaughan
+
+;; Author: Tim Vaughan <tgvaughan@gmail.com>
+;; Created: 19 May 2019
+;; Version: 1.0.0
+;; Keywords:
+;; Homepage: https://github.com/tgvaughan/sixel
+;; Package-Requires: ((emacs "25"))
+
+;;; Commentary:
+
+;;; Code:
+
(defvar test-string
(concat "q"
"#0;2;0;0;0#1;2;100;100;0#2;2;0;100;0"
"#2??GG????-"
"#1!14@"))
-
(defun sixel-get-params (string)
"Retrieve the sixel parameters."
(car (split-string string "q")))
"Retrieve data string."
(substring string (1+ (string-match "q" string))))
-(defun sixel-compute-row-length (string)
- (apply 'max
- (mapcar
- (lambda (substr)
- (apply 'max (mapcar
- (lambda (subsubstr)
- (length (subsubstr)))
- (split-string substr "$"))))
- (split-string string -))))
-
(defun sixel-tag-bits (sixel n tag)
"Set bits of SIXEL corresponding to N with to the value TAG."
(dotimes (i 6)
(aset sixel i tag))
(setq n (/ n 2))))
-(defun sixel-tag-sixel-in-row (row-variable index char tag)
+(defun sixel-tag-sixel-in-row (row index char tag)
"Tag the bits of the sixel at INDEX in the list identified by
the variable ROW-VARIABLE corresponding to input character CHAR
with TAG."
- (while (not (< index (length (symbol-value row-variable))))
- (add-to-list row-variable (make-vector 6 nil)))
- (let ((sixel (elt (symbol-value row-variable) index)))
- (sixel-tag-bits sixel (- char 63) tag)))
+ (while (not (< index (length row)))
+ (push (make-vector 6 nil) row))
+ (let ((sixel (elt row (- (length row) 1 index))))
+ (sixel-tag-bits sixel (- char 63) tag))
+ row)
(defun sixel-process-data (string)
- "Convert sixel string into a list of lists representing individual sixels."
+ "Convert STRING into a list of lists representing individual sixels.
+Returns a sixel image object."
(with-temp-buffer
(insert string)
(goto-char (point-min))
(while (not finished)
(cond
((looking-at "#\\([0-9]+\\);\\([0-9]+\\);\\([0-9]+\\);\\([0-9]+\\);\\([0-9]+\\)")
- (let ((tag (intern (match-string 1)))
+ (let ((tag (format "%02x" (string-to-number (match-string 1))))
(mode (match-string 2))
(r (string-to-number (match-string 3)))
(g (string-to-number (match-string 4)))
(push (list tag r g b) colour-map)))
((looking-at "#\\([0-9]+\\)")
- (let ((tag (intern (match-string 1))))
+ (let ((tag (format "%02x" (string-to-number (match-string 1)))))
(setq current-colour tag)))
- ((looking-at "$")
+ ((looking-at "\\$")
(setq idx-out 0))
- ((looking-at "^-")
- (push this-row 'rows)
+ ((looking-at "-")
+ (push (reverse this-row) rows)
(setq this-row nil)
(setq idx-out 0))
- ((looking-at "^!\\([0-9]+\\)\\([?-~]\\)")
+ ((looking-at "!\\([0-9]+\\)\\([?-~]\\)")
(let ((repeat-count (string-to-number (match-string 1)))
(char (elt (match-string 2) 0)))
(dotimes (i repeat-count)
- (sixel-tag-sixel-in-row 'result idx-out char current-colour))))
+ (setq this-row
+ (sixel-tag-sixel-in-row this-row idx-out char current-colour))
+ (setq idx-out (1+ idx-out)))))
- ((looking-at "^\\([?-~]\\)")
+ ((looking-at "\\([?-~]\\)")
(let ((char (elt (match-string 1) 0)))
- (sixel-tag-sixel-in-row 'result idx-out char current-colour)))
-
- ((= (point) (point-max))
- (setq finished t))
+ (setq this-row
+ (sixel-tag-sixel-in-row this-row idx-out char current-colour))
+ (setq idx-out (1+ idx-out))))
- (t (error "Invalid characters found in input string.")))
+ (t (setq finished t)))
(goto-char (match-end 0)))
- (push this-row 'rows))))
+ (push (reverse this-row) rows)
+ (cons colour-map
+ (reverse rows)))))
+
+(defun sixel-image-colour-map (sixel-image)
+ "Extract colour map from SIXEL-DATA."
+ (car sixel-image))
+
+(defun sixel-image-sixels (sixel-image)
+ "Extract sixels from SIXEL-DATA."
+ (cdr sixel-image))
+
+(defun sixel-image-dims (sixel-image)
+ "Computes image width from SIXEL-DATA. Returns pair (width . height)."
+ (let ((sixels (sixel-image-sixels sixel-image)))
+ (cons
+ (apply #'max (mapcar (lambda (row) (length row)) sixels))
+ (length sixels))))
+
+(defun sixel-image-to-xpm-values (sixel-image)
+ (let* ((dims (sixel-image-dims sixel-image))
+ (colour-map (sixel-image-colour-map sixel-image))
+ (n-colours (length colour-map)))
+ (concat "\""
+ (number-to-string (car dims)) " "
+ (number-to-string (cdr dims)) " "
+ (number-to-string n-colours) " 2\"")))
+
+(defun sixel-image-to-xpm-colours (sixel-image)
+ (let ((colour-map (sixel-image-colour-map sixel-image)))
+ (string-join
+ (mapcar (lambda (colour)
+ (concat
+ "\""
+ (elt colour 0) " "
+ "c #"
+ (format "%02x%02x%02x"
+ (elt colour 1)
+ (elt colour 2)
+ (elt colour 3))
+ "\""))
+ colour-map)
+ ",")))
+
+(defun sixel-to-xpm (string)
+ "Returns an XPM image representation of the SIXEL graphic encoded in STRING."
+ (let* ((param-string (sixel-get-params string))
+ (data-string (sixel-get-data string))
+ (sixel-image (sixel-process-data data-string)))
+ (concat
+ "/* XPM */"
+ "static char * pixmap = {"
+ (sixel-image-to-xpm-values sixel-image) ",\n"
+ (sixel-image-to-xpm-colours sixel-image)
+ ;; (sixel-data-to-XPM-pixels data)
+ "};")))
+
+
+
+;; sixel.el ends here
The Lambda Lab / projects / sixel.git / blobdiff