@node Displaying Boundaries
@section Displaying Boundaries
+@cindex mode, fill-column-indicator
+@findex display-fill-column-indicator-mode
+@findex global-display-fill-column-indicator-mode
+ Emacs can add an indicator to display a fill column position. The
+fill column indicator is a useful functionality specially in
+prog-mode to indicate the position of an specific column.
+
+ You can set the buffer-local variables @code{display-fill-column-indicator}
+and @code{display-fill-column-indicator-character} to activate the
+indicator and controls how the indicator looks.
+
+Alternatively you can type @kbd{M-x display-fill-column-indicator-mode} or
+@kbd{M-x global-display-fill-column-indicator-mode} which enables the indicator
+locally and globally respectively and also chooses the character to
+use if none is set. It is possible to use the first one to activate the
+indicator in a hook or the second one to enable it globally.
+
+There are 2 new buffer local variables and 1 face to customize this
+mode:
+
+@table @code
+@item display-fill-column-indicator-column
+@vindex display-fill-column-indicator-column
+Is the column number where the indicator should be set. It can take
+positive numerical values for the column or the special value t which
+means that the variable 'fill-column' will be used.
+
+Any other value disables the indicator. The default value is t.
+
+@item display-fill-column-indicator-char
+@vindex display-fill-column-indicator-char
+Is the character used for the indicator. This character can be any
+valid char including unicode ones if the actual font supports them.
+
+When the mode is enabled throw the functions
+@code{display-fill-column-indicator-mode} or
+@code{global-display-fill-column-indicator-mode}, the initialization
+functions check if this variable is non-nil, otherwise the
+initialization tries to set it to U+2502 or '|'.
+
+@item fill-column-face
+Is the face used to display the indicator it inherits its default
+values from shadow and the default face.
+@end table
+
@vindex indicate-buffer-boundaries
On graphical displays, Emacs can indicate the buffer boundaries in
the fringes. If you enable this feature, the first line and the last
---
** Emacs now optionally displays a fill column indicator.
-The fill column indicator is a usefull functionality specially in
-prog-mode to indicate the position of a specific column. This is
-similar to what 'fill-column-indicator' package provides, but much
-faster and compatible with show-trailing-whitespace.
+This is similar to what 'fill-column-indicator' package provides, but
+much faster and compatible with show-trailing-whitespace.
Customize the buffer-local variables 'display-fill-column-indicator'
and 'display-fill-column-indicator-character' to activate the
indicator.
-Alternatively you can use the modes
-'display-fill-column-indicator-mode' or the global
-'global-display-fill-column-indicator-mode' which enables it locally
-and globally respectively and also chooses the character to use if no
-one is set.
-
The indicators is not displayed at all in minibuffer windows and
in tooltips, as it is not useful there.