[PATCH]: images for info

[Jan Nieuwenhuizen]

This weekend, Karl has installed my patch to texinfo to make makeinfo
write image information to info files.  From NEWS:

  . makeinfo writes a new construct for @image to the info file, so that
    graphical browsers (such as Emacs Info under X) can display an
    actual image.  Thus, a .txt file substitute is no longer included if
    a real image file is available.

Below is an accompanying patch to emacs' info mode.  The patches and a
small test are also available from

    http://lilypond.org/~jan/info-image

Greetings,
Jan.


Index: lisp/ChangeLog
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/ChangeLog,v
retrieving revision 1.5053
diff -p -u -r1.5053 ChangeLog
--- lisp/ChangeLog      21 Apr 2003 15:43:02 -0000      1.5053
+++ lisp/ChangeLog      21 Apr 2003 16:46:38 -0000
@@ -1,3 +1,10 @@
+2003-04-21  Jan Nieuwenhuizen  <address@hidden>
+
+       * info.el (Info-unescape-quotes)
+       (Info-split-parameter-string)
+       (Info-display-images-node): New functions for displaying images.
+       (Info-select-node): Call Info-display-images-node.
+
 2003-04-20  Richard M. Stallman  <address@hidden>
 
        * simple.el (kill-line): Doc fix.
Index: lisp/info.el
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/info.el,v
retrieving revision 1.342
diff -p -u -r1.342 info.el
--- lisp/info.el        5 Apr 2003 18:01:14 -0000       1.342
+++ lisp/info.el        21 Apr 2003 16:46:40 -0000
@@ -1064,6 +1064,59 @@ a case-insensitive match is tried."
     (if (numberp nodepos)
        (+ (- nodepos lastfilepos) (point)))))
 
+(defun Info-unescape-quotes (value)
+  "Unescape double quotes and backslashes in VALUE"
+  (let ((start 0)
+       (unquote value))
+    (while (string-match "[^\\\"]*\\(\\\\\\)[\\\\\"]" unquote start)
+      (setq unquote (replace-match "" t t unquote 1))
+      (setq start (- (match-end 0) 1)))
+    unquote))
+
+(defun Info-split-parameter-string (parameter-string)
+  "Return alist of (\"KEY\" . \"VALUE\") from PARAMETER-STRING; a
+   whitespace separated list of KEY=VALUE pairs.  If VALUE
+   contains whitespace or double quotes, it must be quoted in
+   double quotes and any double quotes or backslashes must be
+   escaped (\\\",\\\\)."
+  (let ((start 0)
+       (parameter-alist))
+    (while (string-match
+           "\\s *\\([^=]+\\)=\\(?:\\([^\\s 
\"]+\\)\\|\\(?:\"\\(\\(?:[^\\\"]\\|\\\\[\\\\\"]\\)*\\)\"\\)\\)"
+           parameter-string start)
+      (setq start (match-end 0))
+      (push (cons (match-string 1 parameter-string)
+                 (or (match-string 2 parameter-string)
+                     (Info-unescape-quotes
+                      (match-string 3 parameter-string))))
+           parameter-alist))
+    parameter-alist))
+
+(defun Info-display-images-node ()
+  "Display images in current node."
+  (save-excursion
+    (let ((inhibit-read-only t)
+         (case-fold-search t)
+         paragraph-markers)
+      (goto-char (point-min))
+      (while (re-search-forward
+             "\\(\0\b[[]image\\(\\(?:[^\b]\\|[^\0]+\b\\)*\\)\0\b[]]\\)"
+             nil t)
+       (let* ((start (match-beginning 1))
+              (parameter-alist (Info-split-parameter-string (match-string 2)))
+              (src (cdr (assoc-string "src" parameter-alist)))
+              (image-file (if src (if (file-name-absolute-p src) src
+                                    (concat default-directory src))
+                            ""))
+              (image (if (file-exists-p image-file)
+                         (create-image image-file)
+                       "[broken image]")))
+         (message "Found image: %S" image-file)
+         (if (not (get-text-property start 'display))
+             (add-text-properties
+              start (point) `(display ,image rear-nonsticky (display)))))))
+    (set-buffer-modified-p nil)))
+
 (defvar Info-header-line nil
   "If the info node header is hidden, the text of the header.")
 (put 'Info-header-line 'risky-local-variable t)
@@ -1104,6 +1157,7 @@ Bind this in case the user sets it to ni
        (if Info-enable-active-nodes (eval active-expression))
        (Info-fontify-node)
        (setq Info-header-line (get-text-property (point-min) 'header-line))
+       (Info-display-images-node)
        (run-hooks 'Info-selection-hook)))))
 
 (defun Info-set-mode-line ()

-- 
Jan Nieuwenhuizen <address@hidden> | GNU LilyPond - The music typesetter
http://www.xs4all.nl/~jantien       | http://www.lilypond.org