Link type for pdf-tools annotations

["Juan Manuel Macías" <maciaschain@posteo.net>]

Hi,

Many times I need to "save" an annotation point in the pdf-tools
annotations buffer. So I defined a new link type and the function to
store it. The link is stored with the structure:

[[pdf-annot:/path/to/file.pdf::annotation-date][file-name.pdf (annot. on p. page-number)]]

The link opens the PDF and jumps to the specific annotation. A screenshot:

https://i.imgur.com/hw96NfD.png

I share the code here in case it is useful to someone:

#+begin_src emacs-lisp

  (defun my-org-pdf-annot-store-link ()
    (when (equal (format "%s" major-mode) "pdf-annot-list-mode")
      (let* ((pdf-buf pdf-annot-list-document-buffer)
	     (pdf-file (buffer-file-name pdf-buf))
	     (annot (pdf-annot-getannot (tabulated-list-get-id) pdf-buf))
	     (date (pdf-annot-print-property annot 'modified))
	     (page (save-excursion
		     (beginning-of-line)
		     (re-search-forward "\\(^\s+\\)\\([[:digit:]]+\\)" nil t)
		     (match-string 2)))
	     (link (concat "pdf-annot:" pdf-file "::" date))
	     (desc (format "%s (annot. on p. %s)" (file-name-nondirectory pdf-file) page)))
	(org-link-store-props
	 :type "pdf-annot"
	 :link link
	 :description desc))))

  (org-link-set-parameters
   "pdf-annot"
   :follow (lambda (path)
	     (let ((a (if (string-match "::\\(.+\\)" path)
			  (match-string 1 path)
			(error "no annotation date")))
		   (file-path (replace-regexp-in-string "::.+" "" path)))
	       (find-file file-path)
	       (pdf-annot-list-annotations)
	       (let ((anot-buf (format "*%s's annots*"
				       (file-name-sans-extension
					(buffer-name)))))
		 (with-current-buffer anot-buf
		   (save-excursion
		     (goto-char (point-min))
		     (re-search-forward a nil t)
		     (call-interactively #'pdf-annot-list-display-annotation-from-id))))))
   :store #'my-org-pdf-annot-store-link)

#+end_src

Best regards,

Juan Manuel 

-- 
Juan Manuel Macías -- Composición tipográfica, tratamiento de datos, diseño editorial y ortotipografía