how to show latest xkcd in dashboard on startup?

Question

Dashboard can display images on startup. I was wondering how would I give it latest xkcd comic from xkcd-mode?

Answer 1

xkcd-mode uses ~/.emacs.d/xkcd/ to cache the images, xkcd-cache-dir.

So, you just need to set dashboard image variable, dashboard-banner-official-png, as the last cached image, xkcd-latest, and consider that dashboard only accepts png images.

(require 'xkcd)

;; to update cached xkcd
(with-temp-buffer
  (xkcd)
  (xkcd-kill-buffer))

;; setting dashboard image (png)
(let ((last-xkcd-png (concat xkcd-cache-dir (number-to-string xkcd-latest) ".png")))
  (if (file-exists-p last-xkcd-png)
      (setq dashboard-banner-official-png last-xkcd-png)))

If you want to get random xkcd comic, you can use:

(require 'xkcd)

;; to get a rand comic and to set dashboard image (png)
(let ((rand-id-xkcd nil))
  (with-temp-buffer
    (setq rand-id-xkcd (string-to-number (xkcd-rand)))
    (xkcd-kill-buffer))
  (let ((last-xkcd-png (concat xkcd-cache-dir (number-to-string rand-id-xkcd) ".png")))
    (if (file-exists-p last-xkcd-png)
    (setq dashboard-banner-official-png last-xkcd-png))))

If you also want to change dashboard text below the image, dashboard-banner-logo-title, just change (xkcd) for (setq dashboard-banner-logo-title (xkcd)) or (setq rand-id-xkcd (string-to-number (xkcd-rand))) for (setq rand-id-xkcd (string-to-number (setq dashboard-banner-logo-title (xkcd-rand)))).

Don't forget to put this after dashboard config in your init file.