Split off imagemagick-filter-types from imagemagick-register-types

* lisp/image.el: (imagemagick-filter-types): New function.  (Bug#7406)
(imagemagick-register-types): Use imagemagick-filter-types.

* etc/NEWS: Mention this.

2 files changed, 31 insertions, 28 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index c2c6e0da37b..b70008fb821 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -3,7 +3,8 @@
         * image.el: For clarity, call imagemagick-register-types at
         top-level, rather than relying on a custom :initialize.
         (imagemagick-types-enable): New option.  (Bug#11557)
-        (imagemagick-register-types): Respect imagemagick-types-inhibit.
+        (imagemagick-filter-types): New function.  (Bug#7406)
+        (imagemagick-register-types): Use imagemagick-filter-types.
         If disabling support, remove elements altogether rather
         than using an impossible regexp.
         (imagemagick-types-inhibit): Give it the default init function.
diff --git a/lisp/image.el b/lisp/image.el
index 9da6085ee14..394d44c21e9 100644
--- a/lisp/image.el
+++ b/lisp/image.el
@@ -687,21 +687,41 @@ The minimum delay between successive frames is 0.01s."
                       image n count time-elapsed limit))))
 
 
+(defvar imagemagick-types-inhibit)
+(defvar imagemagick-types-enable)
+
+(defun imagemagick-filter-types ()
+  "Return a list of the ImageMagick types to be treated as images, or nil.
+This is the result of `imagemagick-types', including only elements
+that match `imagemagick-types-enable' and do not match
+`imagemagick-types-inhibit'."
+  (when (fboundp 'imagemagick-types)
+    (cond ((null imagemagick-types-enable) nil)
+          ((eq imagemagick-types-inhibit t) nil)
+          ((eq imagemagick-types-enable t) (imagemagick-types))
+          (t
+           (delq nil
+                 (mapcar
+                  (lambda (type)
+                    (unless (memq type imagemagick-types-inhibit)
+                      (catch 'found
+                        (dolist (enable imagemagick-types-enable nil)
+                          (if (cond ((symbolp enable) (eq enable type))
+                                    ((stringp enable)
+                                     (string-match enable (symbol-name type))))
+                              (throw 'found type))))))
+                  (imagemagick-types)))))))
+
 (defvar imagemagick--file-regexp nil
   "File extension regexp for ImageMagick files, if any.
 This is the extension installed into `auto-mode-alist' and
 `image-type-file-name-regexps' by `imagemagick-register-types'.")
 
-(defvar imagemagick-types-inhibit)
-(defvar imagemagick-types-enable)
-
 ;;;###autoload
 (defun imagemagick-register-types ()
   "Register file types that can be handled by ImageMagick.
 This function is called at startup, after loading the init file.
-It registers the ImageMagick types returned by `imagemagick-types',
-including only those from `imagemagick-types-enable', and excluding
-those from `imagemagick-types-inhibit'.
+It registers the ImageMagick types returned by `imagemagick-filter-types'.
 
 Registered image types are added to `auto-mode-alist', so that
 Emacs visits them in Image mode.  They are also added to
@@ -710,27 +730,9 @@ recognizes these files as having image type `imagemagick'.
 
 If Emacs is compiled without ImageMagick support, this does nothing."
   (when (fboundp 'imagemagick-types)
-    (let* ((include
-            (cond ((null imagemagick-types-enable) nil)
-                  ((eq imagemagick-types-inhibit t) nil)
-                  ((eq imagemagick-types-enable t) (imagemagick-types))
-                  (t
-                   (delq nil
-                         (mapcar
-                          (lambda (type)
-                            (catch 'found
-                              (dolist (enable imagemagick-types-enable nil)
-                                (if (cond ((symbolp enable) (eq enable type))
-                                          ((stringp enable)
-                                           (string-match enable
-                                                         (symbol-name type))))
-                                    (throw 'found type)))))
-                          (imagemagick-types))))))
-           (re (let (types)
-                 (dolist (type include)
-                   (unless (memq type imagemagick-types-inhibit)
-                     (push (downcase (symbol-name type)) types)))
-                 (if types (concat "\\." (regexp-opt types) "\\'"))))
+    (let* ((types (mapcar (lambda (type) (downcase (symbol-name type)))
+                          (imagemagick-filter-types)))
+           (re (if types (concat "\\." (regexp-opt types) "\\'")))
            (ama-elt (car (member (cons imagemagick--file-regexp 'image-mode)
                                  auto-mode-alist)))
            (itfnr-elt (car (member (cons imagemagick--file-regexp 'imagemagick)