On Thu, Apr 10, 2025 at 1:56 PM Elijah Gabe Pérez <eg642616@gmail.com>
wrote:

> Tags: patch
>
> This feature flashes the current mode-line face (mode-line-active) once,
> this is intended to be used in `ring-bell-function', but it can be used
> for other purposes.
>
> There have been third-party packages that make this, however many of
> them diverge either in features or in faces.
>
> I think Emacs should have had this built-in.
>

An implementation like the one below protects from erroneously leaving
behind remapped faces:

  (defun my/flash-faces (interval faces &rest specs)
    (let ((cookies (mapcar
                    (lambda (face) (face-remap-add-relative face specs))
                    faces)))
      (unwind-protect
          (sit-for interval)
        (mapc #'face-remap-remove-relative cookies))))

  (defun my/ring-bell-function ()
    (my/flash-faces my:mode-line-ring-bell-interval ; I use 0.05
                    my:mode-line-ring-bell-faces ; I use '(internal-border
tab-bar mode-line-active mode-line-inactive)
                    :background my:mode-line-ring-bell-backround)) ; I use
"Firebrick" (I could have used the foreground from 'error)

  (setq ring-bell-function (if my:mode-line-ring-bell-interval ; I allow my
users to disable this
                               #'my/ring-bell-function
                             nil))