Getting a list of figures in an org-buffer

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Similar to the previous example of getting a list of tables, here we examine getting a list of figures. Here are two figure links, one with a label, and one with a caption.

Figure 1: An equation of state. this is the caption of the figure.

Figure 2: another figure

We define a link that will parse the buffer, and create links in a new buffer to the figures. We define a figure as a link with a :type of "file" that has a path that points to a file ending with png or pdf. We will improve on the list of tables by making the buffer read-only, and making a local key binding to kill the buffer by pressing "q". Here is our attempted code.

;; http://www.emacswiki.org/emacs/ElispCookbook#toc4
(defun string/ends-with (s ending)
  "return non-nil if string S ends with ENDING."
  (cond ((>= (length s) (length ending))
         (let ((elength (length ending)))
           (string= (substring s (- 0 elength)) ending)))
        (t nil)))

(org-add-link-type 
 "list-of-figures"
 (lambda (link-string)
   (let* ((c-b (buffer-name))
          (counter 0)
          (list-of-figures 
           (org-element-map (org-element-parse-buffer) 'link
             (lambda (link) 
               "create a link for to the figure"
               (when 
                   (and (string= (org-element-property :type link) "file")
                        (string-match-p  
                         "[^.]*\\.\\(png\\|jpg\\)$"
                         (org-element-property :path link)))                   
                 (incf counter)
                 
                 (let* ((start (org-element-property :begin link))
                        (parent (car (cdr (org-element-property :parent link))))
                        (caption (caaar (plist-get parent :caption)))
                        (name (plist-get parent :name)))
                   (if caption 
                       (format 
                        "[[elisp:(progn (switch-to-buffer \"%s\")(goto-char %s))][figure %s: %s]] %s\n" 
                        c-b start counter (or name "") caption)
                     (format 
                      "[[elisp:(progn (switch-to-buffer \"%s\")(goto-char %s))][figure %s: %s]]\n" 
                      c-b start counter (or name "")))))))))
          (switch-to-buffer "*List of Figures*")
          (org-mode)
          (erase-buffer)
          (insert (mapconcat 'identity list-of-figures ""))
          (setq buffer-read-only t)
          (use-local-map (copy-keymap org-mode-map))
          (local-set-key "q" #'(lambda () (interactive) (kill-buffer)))))
   (lambda (keyword desc format)
     (cond
      ((eq format 'latex)
       (format "\\listoffigures")))))

This is a test to see if our function works for other image types. smiley.jpg

And a link to test it out:

This works too. I am not sure I am getting the figure name and caption in a bulletproof way. They seem to be buried in the :parent of the element, which is a paragraph element. The caption seems to be buried in a few sets of parentheses, hence the use of caaar to get the caption out. I am not sure if the caption is always at that depth or not. As a proof of concept though, this is not too bad.

Copyright (C) 2014 by John Kitchin. See the License for information about copying.

org-mode source

Org-mode version = 8.2.5h

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