Automatic preview generation with AUCTeX

Question

Right now, when using AUCTeX's preview feature, I have to manually refresh the previews after I change existing sources or write new text. I have to run preview-document every time, which is both inconvenient and inefficient, and it may take a while to re-generate previews for the whole document. I'm looking for a way to

1. Automatically generate previews when I open a document.
2. Automatically update previews on save.
3. Only (re-)compile previews for new and updated pieces of text.

Is there a way to do this with AUCTeX?

Answer 1

Why not use preview-at-point? Whenever I edit a snippet, I do a quick C-c C-c C-p (which I think is the default) to recompile only that one part. preview-region (C-c C-c C-r) is also useful to avoid having to recompile the entire document.

Answer 2

I am trying to achieve the same, this is what I could do so far

(use-package tex-mode
  :ensure auctex
  :hook (latex-mode . (lambda ()
                        (add-hook 'after-save-hook (lambda ()
                                                     (preview-document))))))

Now, this doesn't actually work and I don't know why, but it could be a step further.

Please reply if you were able to find a solution.

Answer 3

The following code in your init file solves your questions

1. Preview on file-open
2. Preview on save-buffer

(setq preview-auto-cache-preamble t
      TeX-show-compilation nil)

(defun my-initial-preview ()
  "Generate preview at `find-file'."
  (save-excursion
    (preview-document)))

(define-minor-mode my-preview-at-save-mode
  "Preview at `save-buffer'."
  :key ""
  (if my-preview-at-save-mode
      (add-hook 'after-save-hook #'my-initial-preview nil t)
    (remove-hook 'after-save-hook #'my-initial-preview)))

;; The Preview package puts `preview-mode-setup` into `LaTeX-mode-hook`.
;; It is important that `my-initial-preview` comes after `preview-mode-setup`.
;; Therefore, we use `with-eval-after-load` and
;; the value `t` for the `depth` argument of `add-hook`.
(with-eval-after-load 'preview
  (add-hook 'LaTeX-mode-hook #'my-initial-preview t)
  (add-hook 'LaTeX-mode-hook #'my-preview-at-save-mode))

Your question 3 has already been answered by mbsmu. You just use preview-at-point.

Tested with Gnu Emacs 28.1.