+;;; sixel.el --- minor mode for processing sixel graphics
+
+;; Copyright (C) 2019 Tim Vaughan
+
+;; Author: Tim Vaughan <plugd@thelambdalab.xyz>
+;; Created: 19 May 2019
+;; Version: 1.0.0
+;; Keywords:
+;; Homepage: gopher://thelambdalab.xyz/1/projects/sixel
+;; Package-Requires: ((emacs "26"))
+
+;;; Commentary:
+
+;; This file is not part of GNU Emacs.
+
+;; This program is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with this file. If not, see <http://www.gnu.org/licenses/>.
+
+;;; Code:
+
(defvar test-string
- (concat "q"
+ (concat "\ePq"
"#0;2;0;0;0#1;2;100;100;0#2;2;0;100;0"
"#1~~@@vv@@~~@@~~$"
- "#2??GG????-"
- "#1!14@"))
-
+ "#2??}}GG}}??}}??-"
+ "#1!14@\e\\"))
(defun sixel-get-params (string)
"Retrieve the sixel parameters."
- (car (split-string string "q")))
+ (car (split-string (substring string 2) "q")))
(defun sixel-get-data (string)
"Retrieve data string."
(substring string (1+ (string-match "q" string))))
-(defvar sixel-colour-map nil
- "Map of two-character names to RGB colour triples.")
-
-(defvar sixel-current-colour nil
- "Current colour.")
-
-(defun sixel-compute-row-length (string)
- (apply 'max
- (mapcar
- (lambda (substr)
- (apply 'max (mapcar
- (lambda (subsubstr)
- (length (subsubstr)))
- (split-string substr "$"))))
- (split-string string -))))
-
-(defun sixel-tag-bits (n tag bit-count)
- "Create a list of length BIT-COUNT with the elements corresponding to the
-true bits of N set to TAG."
- (if (= bit-count 0)
- nil
- (cons (if (= (% n 2) 1)
- tag
- nil)
- (sixel-tag-bits (/ n 2) tag (1- bit-count)))))
-
-(defun sixel-make-sixel-from-char (char tag)
- "Retrieve sequence of bits to be set."
- (sixel-tag-bits (- char 63) tag 6))
-
-(defun sixel-union (sixel1 sixel2)
- "Returns a union of the two sixels, SIXEL1 and SIXEL2.
-When both sixels specify a tag for the same pixel, the tag
-from SIXEL2 wins."
- (seq-mapn (lambda (tag1 tag2)
- (or tag2 tag1))
- sixel1 sixel2))
-
-(defun sixel-process-row (string)
- (let ((idx-in 0)
- (idx-out 0)
- result)
- (while (< idx-in (length string))
- (let (trunc-string (substring string index-in))
+(defun sixel-tag-bits (sixel n tag)
+ "Set bits of SIXEL corresponding to N with to the value TAG."
+ (dotimes (i 6)
+ (if (= (% n 2) 1)
+ (aset sixel i tag))
+ (setq n (/ n 2))))
+
+(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 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 STRING into a list of lists representing individual sixels.
+Returns a sixel image object."
+ (with-temp-buffer
+ (insert string)
+ (goto-char (point-min))
+ (let ((idx-out 0)
+ this-row rows
+ current-colour colour-map
+ finished)
+ (while (not finished)
(cond
- ((string-match "^#\\([0-9]+\\);\\([0-9]+\\);\\([0-9]+\\);\\([0-9]+\\);\\([0-9]+\\)"
- trunc-string)
- (let ((tag (intern (string-to (match-string 1 trunc-string))))
- (mode (match-string 2 trunc-string))
- (r (string-to-number (match-string 3 trunc-string)))
- (g (string-to-number (match-string 4 trunc-string)))
- (b (string-to-number (match-string 5 trunc-string))))
- (add-to-list 'sixel-colour-map (list (tag r g b)))
- (setq idx-in (match-end 0))))
- ((string-match "^#\\([0-9]+\\)" trunc-string)
- (let ((tag (intern (match-string 1 trunc-string))))
- (setq current-colour tag)
- (setq idx-in (match-end 0))))
- ((string-match "^!\\([0-9]+\\)\\([?-~]\\)" trunc-string)
- (let ((repeat-count (string-to-number (match-string 1 trunc-string)))
- (char (elt (match-string 2 trunc-string) 0)))
+ ;; Define colour:
+ ((looking-at "#\\([0-9]+\\);\\([0-9]+\\);\\([0-9]+\\);\\([0-9]+\\);\\([0-9]+\\)")
+ (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)))
+ (b (string-to-number (match-string 5))))
+ (push (list tag r g b) colour-map)))
+ ;; Set current colour:
+ ((looking-at "#\\([0-9]+\\)")
+ (let ((tag (format "%02x" (string-to-number (match-string 1)))))
+ (setq current-colour tag)))
+ ;; Carriage return:
+ ((looking-at "\\$")
+ (setq idx-out 0))
+ ;; New line:
+ ((looking-at "-")
+ (push (reverse this-row) rows)
+ (setq this-row nil)
+ (setq idx-out 0))
+ ;; RLE sixel char sequence:
+ ((looking-at "!\\([0-9]+\\)\\([?-~]\\)")
+ (let ((repeat-count (string-to-number (match-string 1)))
+ (char (elt (match-string 2) 0)))
(dotimes (i repeat-count)
- (unless (< idx-out (length result))
- (add-to-list result (make-vector 6 nil)))
- (let ((sixel (elt result idx-out))))))))))))
-
-
+ (setq this-row
+ (sixel-tag-sixel-in-row this-row idx-out char current-colour))
+ (setq idx-out (1+ idx-out)))))
+ ;; Sixel char:
+ ((looking-at "\\([?-~]\\)") ; Sixel char
+ (let ((char (elt (match-string 1) 0)))
+ (setq this-row
+ (sixel-tag-sixel-in-row this-row idx-out char current-colour))
+ (setq idx-out (1+ idx-out))))
+ ;; Termination sequence:
+ ((looking-at "\e\\\\")
+ (setq finished t))
+ ;; Skip other char:
+ ((looking-at "[[:ascii:]]")))
+ (goto-char (match-end 0)))
+ (push (reverse this-row) rows)
+ (cons colour-map
+ (reverse rows)))))
+
+(defun sixel-pad-rows (sixel-image)
+ "Pad out contents of rows in SIXEL-IMAGE so that all rows are the same length."
+ (let ((width (car (sixel-image-dims sixel-image)))
+ (rows (cdr sixel-image)))
+ (dotimes (row-idx (length rows))
+ (let* ((row-cdr (nthcdr row-idx rows))
+ (row-width (length (car row-cdr))))
+ (if (< row-width width)
+ (setcar row-cdr (append (car row-cdr)
+ (make-list (- width row-width)
+ [nil nil nil nil nil nil])))))))
+ sixel-image)
+
+(defun sixel-image-colour-map (sixel-image)
+ "Extract colour map from SIXEL-IMAGE."
+ (car sixel-image))
+
+(defun sixel-image-sixels (sixel-image)
+ "Extract sixels from SIXEL-IMAGE."
+ (cdr sixel-image))
-(sixel-get-rows test-string)
+(defun sixel-image-dims (sixel-image)
+ "Compute image width from SIXEL-IMAGE. Return pair (width . height)."
+ (let ((sixels (sixel-image-sixels sixel-image)))
+ (cons
+ (apply #'max (mapcar (lambda (row) (length row)) sixels))
+ (* 6 (length sixels)))))
+
+(defun sixel-image-to-xpm-values (sixel-image)
+ "Produce parameter values component of XPM representation of SIXEL-IMAGE."
+ (let* ((dims (sixel-image-dims sixel-image))
+ (colour-map (sixel-image-colour-map sixel-image))
+ (n-colours (1+ (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)
+ "Produce colour definitions component of XPM representation of SIXEL-IMAGE."
+ (let ((colour-map (sixel-image-colour-map sixel-image)))
+ (concat
+ (string-join
+ (mapcar (lambda (colour)
+ (concat
+ "\""
+ (elt colour 0) " "
+ "c #"
+ (format "%02x%02x%02x"
+ (/ (* 255 (elt colour 1)) 100)
+ (/ (* 255 (elt colour 2)) 100)
+ (/ (* 255 (elt colour 3)) 100))
+ "\""))
+ colour-map)
+ ",\n")
+ ",\n"
+ "\"-- c #000000\"")))
+
+(defun sixel-image-to-xpm-pixels (sixel-image)
+ "Produce pixels component of XPM representation of SIXEL-IMAGE."
+ (concat
+ "\""
+ (string-join
+ (mapcar (lambda (sixel-row)
+ (string-join
+ (mapcar (lambda (i)
+ (string-join
+ (mapcar (lambda (sixel)
+ (let ((pixel (elt sixel i)))
+ (if pixel
+ pixel
+ "--")))
+ sixel-row)))
+ (number-sequence 0 5))
+ "\",\n\""))
+ (sixel-image-sixels sixel-image))
+ "\",\n\"")
+ "\""))
(defun sixel-to-xpm (string)
- "Converts the given sixel string into an XPM image."
+ "Return 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-pad-rows (sixel-process-data data-string))))
+ (if (string-prefix-p "\eP" string)
+ (concat
+ "/* XPM */"
+ "static char * pixmap[] = {"
+ (sixel-image-to-xpm-values sixel-image) ",\n"
+ (sixel-image-to-xpm-colours sixel-image) ",\n"
+ (sixel-image-to-xpm-pixels sixel-image) "};")
+ (error "Incorrecly formatted sixel string"))))
+
+(defun sixel-render-images-in-buffer ()
+ "Find and render any sixel images in the current buffer."
+ (interactive)
+ (save-excursion
+ (goto-char (point-min))
+ (while (re-search-forward "\eP[[:ascii:]]*\e\\\\" nil t)
+ (let ((sixel-string (match-string 0))
+ (inhibit-read-only t))
+ (delete-region (match-beginning 0)
+ (match-end 0))
+ (insert-image
+ (create-image (sixel-to-xpm sixel-string) 'xpm t))
+ (insert "\n")))))
+
+(defgroup sixel nil
+ "Render sixel images."
+ :group 'multimedia)
- (let* ((sp (split-string string "q"))
- (control-string (car sp))
- ())))
+(define-minor-mode sixel-mode
+ "A minor mode which renders sixel graphics." nil "sixel" nil
+ (add-hook 'after-change-functions
+ (lambda (start end size)
+ (sixel-render-images-in-buffer)
+ (message "Render complete."))
+ nil t))
+
+;;; sixel.el ends here
The Lambda Lab / projects / sixel.git / blobdiff