bug#25905: 25.1; Can't find regexp and replace in SVG files

[Juri Linkov]

>> +(defun image-mode-isearch-filter (_beg _end)
>> +  "Show image as text when trying to search in the image buffer."
>> +  (when (and (derived-mode-p 'image-mode)
>> +             (image-get-display-property))
>> +    (image-mode-as-text))
>> +  t)
>
> This would switch to text representation for all images, though.  Is
> that what we want?  Hm...  perhaps?

It makes sense to do this even in binary formats when
the user wants to search the text of e.g. EXIF tags, etc.

> So that's a good solution for isearch, but I don't think we'd want that
> for search/replace.  Possibly.

This is what OP wanted (unfortunately, mails to his mailbox bounce back).
But we could install the patch anyway.  The only problem I noticed
that the previous patch shows isearch highlighting at wrong places
because there is a need to wrap the call to image-mode-as-text
in save-match-data (alas, global match data bites again).

diff --git a/lisp/image-mode.el b/lisp/image-mode.el
index 032ebf3873..fdac7164d4 100644
--- a/lisp/image-mode.el
+++ b/lisp/image-mode.el
@@ -667,6 +667,9 @@ image-mode--setup-mode
   (when image-auto-resize-on-window-resize
     (add-hook 'window-state-change-functions #'image--window-state-change nil 
t))
 
+  (add-function :before-while (local 'isearch-filter-predicate)
+                #'image-mode-isearch-filter)
+
   (run-mode-hooks 'image-mode-hook)
   (let ((image (image-get-display-property))
        (msg1 (substitute-command-keys
@@ -782,6 +785,14 @@ image-toggle-display-text
     (if (called-interactively-p 'any)
        (message "Repeat this command to go back to displaying the image"))))
 
+(defun image-mode-isearch-filter (_beg _end)
+  "Show image as text when trying to search in the image buffer."
+  (save-match-data
+    (when (and (derived-mode-p 'image-mode)
+               (image-get-display-property))
+      (image-mode-as-text)))
+  t)
+
 (defvar archive-superior-buffer)
 (defvar tar-superior-buffer)
 (declare-function image-flush "image.c" (spec &optional frame))