If you’re like me, you probably like playing with new Emacs color themes from time to time. Sure, I’m the person behind the Emacs ports of Zenburn and Solarized, but as much as I like them, even I get bored with them occasionally.1

What I often do is to install a bunch of themes (e.g. using M-x package-install) and to quickly try them out by evaluating snippets like the ones below in Emacs:

(load-theme 'catppuccin t)

(load-theme 'dracula t)

(load-theme 'gruvbox t)

One small problem with this, though, is that Emacs themes were designed in such a way that one theme can be applied on top of another one. (loading a new theme doesn’t unload the previusly loaded one) In practice this often means that if you load a few themes one after another they’ll start to mess each other up. There are several ways to address this, the simplest being to call disable-theme every time before loading a new theme:

(load-theme 'catppuccin t)

(disable-theme 'catppuccin)
(load-theme 'dracula t)

(disable-theme 'dracula)
(load-theme 'gruvbox t)

Or you can get more adventurous and create a small command that unloads all loaded themes, effectively resetting the theme to Emacs’s default one:

(defun er-disable-all-active-themes ()
  "Disable all currently active themes."
  (interactive)
  (dolist (theme custom-enabled-themes)
    (disable-theme theme)))

Now, you can simply do M-x disable-all-active-themes when you see fit. Finally, you can consider creating a function complementary to load-theme that unloads all active themes before loading the new one:

(defun er-load-theme (theme)
  (er-disable-all-active-themes)
  (load-theme theme t))

(er-load-theme 'catppuccin t)

(er-load-theme 'dracula t)

(er-load-theme 'gruvbox t)

Pretty neat!

That’s all I have for you on this subject. Keep hacking!

  1. Zenburn is to this day my all time favorite theme, though. I rarely manage to spend more than a few days away from it. ↩