Function: display-fill-column-indicator-mode

display-fill-column-indicator-mode is an autoloaded, interactive and byte-compiled function defined in display-fill-column-indicator.el.gz.

Signature

(display-fill-column-indicator-mode &optional ARG)

Documentation

Toggle display of fill-column indicator.

This uses display-fill-column-indicator internally.

To change the position of the column displayed by default customize display-fill-column-indicator-column. You can change the character for the indicator setting display-fill-column-indicator-character. The globalized version is global-display-fill-column-indicator-mode(var)/global-display-fill-column-indicator-mode(fun), which see. This minor mode assumes the buffer uses a fixed-pitch font; if you use variable-pitch fonts, the indicators on different lines might not appear aligned. See Info node (emacs)Displaying Boundaries for details.

This is a minor mode. If called interactively, toggle the Display-Fill-Column-Indicator mode mode. If the prefix argument is positive, enable the mode, and if it is zero or negative, disable the mode.

If called from Lisp, toggle the mode if ARG is toggle. Enable the mode if ARG is nil, omitted, or is a positive number. Disable the mode if ARG is a negative number.

To check whether the minor mode is enabled in the current buffer, evaluate display-fill-column-indicator-mode(var)/display-fill-column-indicator-mode(fun).

The mode's hook is called both when the mode is enabled and when it is disabled.

View in manual

Probably introduced at or before Emacs version 28.1.

Key Bindings

Source Code

;; Defined in /usr/src/emacs/lisp/display-fill-column-indicator.el.gz
;;;###autoload
(define-minor-mode display-fill-column-indicator-mode
  "Toggle display of `fill-column' indicator.
This uses `display-fill-column-indicator' internally.

To change the position of the column displayed by default
customize `display-fill-column-indicator-column'.  You can change the
character for the indicator setting `display-fill-column-indicator-character'.
The globalized version is `global-display-fill-column-indicator-mode',
which see.
This minor mode assumes the buffer uses a fixed-pitch font; if you
use variable-pitch fonts, the indicators on different lines might
not appear aligned.
See Info node `Displaying Boundaries' for details."
  :lighter nil
  (if display-fill-column-indicator-mode
      (progn
        (setq display-fill-column-indicator t)
        (unless display-fill-column-indicator-character
          (setq display-fill-column-indicator-character
                (if (and (char-displayable-p ?\u2502)
                         (or (not (display-graphic-p))
                             (eq (aref (query-font (car (internal-char-font nil ?\u2502))) 0)
                                 (face-font 'default))))
                    ?\u2502
                  ?|))))
    (setq display-fill-column-indicator nil)))