Doc fixes for imagemagick support code.

[bpt/emacs.git] / lisp / image.el

diff --git a/lisp/image.el b/lisp/image.el
index 282b81d..3f44be8 100644 (file)
--- a/lisp/image.el
+++ b/lisp/image.el
@@ -1,7 +1,6 @@
 ;;; image.el --- image API
 
-;; Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
-;;   2007, 2008, 2009, 2010, 2011  Free Software Foundation, Inc.
+;; Copyright (C) 1998-2011  Free Software Foundation, Inc.
 
 ;; Maintainer: FSF
 ;; Keywords: multimedia
@@ -61,7 +60,7 @@ IMAGE-TYPE must be a pair (PREDICATE . TYPE).  PREDICATE is called
 with one argument, a string containing the image data.  If PREDICATE returns
 a non-nil value, TYPE is the image's type.")
 
-(defconst image-type-file-name-regexps
+(defvar image-type-file-name-regexps
   '(("\\.png\\'" . png)
     ("\\.gif\\'" . gif)
     ("\\.jpe?g\\'" . jpeg)
@@ -699,29 +698,38 @@ shall be displayed."
 \f
 (defcustom imagemagick-types-inhibit
   '(C HTML HTM TXT PDF)
-  ;; FIXME what are the possible options?
-  ;; Are these actually file-name extensions?
-  ;; Why are these upper-case when eg image-types is lower-case?
-  "Types the ImageMagick loader should not try to handle."
-  :type '(choice (const :tag "Let ImageMagick handle all the types it can" nil)
+  "ImageMagick types that Emacs should not use ImageMagick to handle.
+This should be a list of symbols, each of which has the same
+names as one of the format tags used internally by ImageMagick;
+see `imagemagick-types'.  Entries in this list are excluded from
+being registered by `imagemagick-register-types'.
+
+If Emacs is compiled without ImageMagick, this variable has no effect."
+  :type '(choice (const :tag "Let ImageMagick handle all types it can" nil)
                 (repeat symbol))
   :version "24.1"
   :group 'image)
 
 ;;;###autoload
 (defun imagemagick-register-types ()
-  "Register the file types that ImageMagick is able to handle."
-  (let ((im-types (imagemagick-types)))
-    (dolist (im-inhibit imagemagick-types-inhibit)
-      (setq im-types (remove im-inhibit im-types)))
-    (dolist (im-type im-types)
-      (let ((extension (downcase (symbol-name im-type))))
-       (push
-        (cons (concat "\\." extension "\\'") 'image-mode)
-        auto-mode-alist)
-       (push
-        (cons (concat "\\." extension "\\'") 'imagemagick)
-        image-type-file-name-regexps)))))
+  "Register file types that can be handled by ImageMagick.
+This adds the file types returned by `imagemagick-types'
+\(excluding the ones in `imagemagick-types-inhibit') to
+`auto-mode-alist' and `image-type-file-name-regexps', so that
+Emacs visits them in Image mode.
+
+If Emacs is compiled without ImageMagick support, do nothing."
+  (when (fboundp 'imagemagick-types)
+    (let ((im-types (imagemagick-types)))
+      (dolist (im-inhibit imagemagick-types-inhibit)
+       (setq im-types (delq im-inhibit im-types)))
+      (dolist (im-type im-types)
+       (let ((extension
+              (concat "\\." (downcase (symbol-name im-type))
+                      "\\'")))
+         (push (cons extension 'image-mode) auto-mode-alist)
+         (push (cons extension 'imagemagick)
+               image-type-file-name-regexps))))))
 
 (provide 'image)