Re: Automatic face re-application with frame-set-background-mode

> From: Antonio Romano <[email protected]>
> Cc: [email protected]
> Date: Mon, 24 Aug 2026 09:13:12 +0000
> 
> 
> To my previous message:
> 
> Antonio Romano <[email protected]> writes:
> > It says it does recalculate faces, but that's not always the case as
> > we've just said that reloading the theme is needed.

If you can suggest a more accurate documentation, based on everything
you've learned, feel free.

> I'm adding that I've been browsing custom theme codes over the web and
> found this[1] in solarized-theme.el:
> 
> --8<---------------cut here---------------start------------->8---
> (cl-defun solarized-update-background-mode
>     (appearance &optional (frames (frame-list)))
>   "Set the APPEARANCE of all frames to either 'light or 'dark.
> This is not specific to Solarized – it will update the appearance of any theme
> that observes the background characteristic."
>   (setq frame-background-mode appearance)
>   (mapc #'frame-set-background-mode frames)
>   ;; Supposedly #'frame-set-background-mode updates the faces, but it doesn’t
>   ;; seem to actually., so re-enable all the themes.
>   (mapc #'enable-theme (reverse custom-enabled-themes))
>   ;; For some reason, ‘enable-theme’ (or maybe ‘solarized’?) is resetting the
>   ;; ‘frame-background-mode’, so reset it here.
>   (setq frame-background-mode appearance))
> --8<---------------cut here---------------end--------------->8---
> 
> So it seems that reloading the theme is the way to go, and also that I'm
> not the only one confused by the way `frame-set-background-mode` operates.

Feel free to report a bug, if you think that's what it is.  I
personally won't touch this with a 3-mile pole, as this stuff is
already devilishly complex, what with all the possible ways of
customizing faces, but maybe some other brave soul will...