Add function for rendering sixel graphics in current buffer.

[sixel.git] / sixel.el

diff --git a/sixel.el b/sixel.el
index 81fa32e..5448ab4 100644 (file)
--- a/sixel.el
+++ b/sixel.el
@@ -5,7 +5,7 @@
 ;; Author: Tim Vaughan <tgvaughan@gmail.com>
 ;; Created: 19 May 2019
 ;; Version: 1.0.0
-;; Keywords: 
+;; Keywords:
 ;; Homepage: https://github.com/tgvaughan/sixel
 ;; Package-Requires: ((emacs "25"))
 
@@ -101,24 +101,36 @@ Returns a sixel image object."
       (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-DATA."
+  "Extract colour map from SIXEL-IMAGE."
   (car sixel-image))
 
 (defun sixel-image-sixels (sixel-image)
-  "Extract sixels from SIXEL-DATA."
+  "Extract sixels from SIXEL-IMAGE."
   (cdr sixel-image))
 
 (defun sixel-image-dims (sixel-image)
-  "Computes image width from SIXEL-DATA. Returns pair (width . height)."
+  "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 string representing parameter values component of XPM
-representation of 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))))
@@ -128,8 +140,7 @@ representation of SIXEL-IMAGE."
             (number-to-string n-colours) " 2\"")))
 
 (defun sixel-image-to-xpm-colours (sixel-image)
-  "Produce string representing colour definitions component of XPM
-representation of SIXEL-IMAGE."
+  "Produce colour definitions component of XPM representation of SIXEL-IMAGE."
   (let ((colour-map (sixel-image-colour-map sixel-image)))
     (concat
      (string-join
@@ -139,9 +150,9 @@ representation of SIXEL-IMAGE."
                  (elt colour 0) " "
                  "c #"
                  (format "%02x%02x%02x"
-                         (elt colour 1)
-                         (elt colour 2)
-                         (elt colour 3))
+                         (/ (* 255 (elt colour 1)) 100)
+                         (/ (* 255 (elt colour 2)) 100)
+                         (/ (* 255 (elt colour 3)) 100))
                  "\""))
               colour-map)
       ",\n")
@@ -149,8 +160,7 @@ representation of SIXEL-IMAGE."
      "\"-- c #000000\"")))
 
 (defun sixel-image-to-xpm-pixels (sixel-image)
-  "Produce string representating pixels component of XPM representation
-of SIXEL-IMAGE."
+  "Produce pixels component of XPM representation of SIXEL-IMAGE."
   (concat
    "\""
    (string-join
@@ -171,10 +181,10 @@ of SIXEL-IMAGE."
    "\""))
 
 (defun sixel-to-xpm (string)
-  "Returns an XPM image representation of the SIXEL graphic encoded in STRING."
+  "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-process-data data-string)))
+         (sixel-image (sixel-pad-rows (sixel-process-data data-string))))
     (if (string-prefix-p "\eP" string)
         (concat
          "/* XPM */"
@@ -182,6 +192,20 @@ of SIXEL-IMAGE."
          (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."))))
+      (error "Incorrecly formatted sixel string"))))
 
-;; sixel.el ends here
+(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")))))
+
+;;; sixel.el ends here