emacs-framebuffer

commit b96b08d54202a1e017de90b1166d06753d65d601
parent bfde63ffe01ad3b40b29b46fbec2f299ed8d9f5b
Author: Tomas Hlavaty <tom@logand.com>
Date:   Sun, 24 May 2020 03:55:58 +0200

use framebuffer-png-size instead of file program

Diffstat:
M
emacs-framebuffer.el
 | 
55
+++++++++++++++++++++++++++++++++++++++++++++++++++----

1 file changed, 51 insertions(+), 4 deletions(-)
diff --git a/emacs-framebuffer.el b/emacs-framebuffer.el
@@ -36,11 +36,58 @@
     (insert (format "0;1;%d;%d;%d;%d;;;;;%s\n" x y w h (expand-file-name file)))
     (call-process-region (point-min) (point-max) "w3mimgdisplay")))
 
-(defun framebuffer-image-size (file)
+(defun framebuffer-buffer-brook ()
+  (lambda ()
+    (let ((z (char-after)))
+      (when z
+        (goto-char (1+ (point)))
+        z))))
+
+(defun framebuffer-next-u8 (brook)
+  (let ((z (funcall brook)))
+    (when z
+      (if (<= 0 z 255)
+          z
+        (error "expected octet, got %s" z)))))
+
+(defun framebuffer-next-u16 (brook)
+  (+ (* 256 (framebuffer-next-u8 brook))
+     (framebuffer-next-u8 brook)))
+
+(defun framebuffer-next-u32 (brook)
+  (+ (* 65536 (framebuffer-next-u16 brook))
+     (framebuffer-next-u16 brook)))
+
+(defun framebuffer-png-size (file)
   (with-temp-buffer
-    (call-process "file" nil t nil (expand-file-name file))
-    (search-backward-regexp ", \\([0-9]+\\)+x\\([0-9]+\\),")
-    (cons (read (match-string 1)) (read (match-string 2)))))
+    (set-buffer-multibyte nil)
+    (insert-file-contents-literally file)
+    (let ((brook (framebuffer-buffer-brook)))
+      (when (and (= 137 (funcall brook))
+                 (= 80 (funcall brook))
+                 (= 78 (funcall brook))
+                 (= 71 (funcall brook))
+                 (= 13 (funcall brook))
+                 (= 10 (funcall brook))
+                 (= 26 (funcall brook))
+                 (= 10 (funcall brook))
+                 (<= 12 (framebuffer-next-u32 brook))
+                 (= ?I (funcall brook))
+                 (= ?H (funcall brook))
+                 (= ?D (funcall brook))
+                 (= ?R (funcall brook)))
+        (cons (framebuffer-next-u32 brook)
+              (framebuffer-next-u32 brook))))))
+
+(defun framebuffer-image-size (file)
+  (cond
+   ((string-match "png\\|PNG" (file-name-extension file))
+    (framebuffer-png-size file))
+   (t
+    (with-temp-buffer
+      (call-process "file" nil t nil (expand-file-name file))
+      (search-backward-regexp ", \\([0-9]+\\)+x\\([0-9]+\\),")
+      (cons (read (match-string 1)) (read (match-string 2)))))))
 
 (defun framebuffer-image-file (file)
   (interactive "fFile: ")