From: Tim Vaughan <tgvaughan@gmail.com>
Date: Mon, 20 May 2019 20:45:11 +0000 (+0200)
Subject: XPM values and colours output working.
X-Git-Url: https://thelambdalab.xyz/gitweb/index.cgi?p=sixel.git;a=commitdiff_plain;h=6b9058e99e890e33246c6e4e3cad2d4dc81dd951

XPM values and colours output working.
---

diff --git a/sixel.el b/sixel.el
index ed46c76..f2532e5 100644
--- a/sixel.el
+++ b/sixel.el
@@ -46,7 +46,8 @@ with TAG."
   row)
 
 (defun sixel-process-data (string)
-  "Convert 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))
@@ -57,7 +58,7 @@ with TAG."
       (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)))
@@ -65,7 +66,7 @@ with TAG."
             (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 "\\$")
@@ -94,7 +95,62 @@ with TAG."
 
         (goto-char (match-end 0)))
       (push (reverse this-row) rows)
-      (list color-map
+      (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