This page is about libraries that highlight the current column of characters.

== Standard Library `hi-lock.el' ==

GnuEmacs version 27 has library `##hi-lock.el##', which provides a local minor mode for highlighting interactively regular expressions `M-s h r'(command <code>highlight-regexp</code>), and, for this topic, subexpressions, using the subexpression number as an option. Then a color background marker could be set at an exact position. For example a pink background for the 72th characters of the line, namely after 71 previous characters at the beginning of the line with

   C-u 1 M-s h r ^.\{71\}\(.\)<ret> hi-pink

See [[Manual:Highlight Interactively]].


== Library `column-marker.el' ==

Library ColumnMarker lets you highlight and unhighlight any column. With no prefix argument, the commands `column-marker-1', `column-marker-2', and `column-marker-3' highlight the current column. The highlighting stays on that column until you highlight a different one or remove the highlighting.

[:col-highlight.el]
== Library `col-highlight.el' ==

Library Lisp:col-highlight.el uses and extends VlineMode in several ways. It provides these commands:

* `toggle-highlight-column-when-idle' -- Highlight the current column whenever Emacs is idle more than a certain number of seconds.

* `column-highlight-mode' -- Continually highlight the current column, tracking the TextCursor as it moves. If you bind this to a key, you can also use it to briefly show the current column, by hitting the key twice.

* `flash-column-highlight' -- Highlight the current column for `col-highlight-period' seconds. Another way to show the current column temporarily.

Using [[user option]] '''`col-highlight-show-only'''' you can restrict the current-column highlight to the current text section of a particular kind (paragraph, defun, sentence, page, etc.).

(Easy installation using AutoInstall: `M-x auto-install-batch col-highlight' -- [[rubikitch]])

'''See Also:'''

* HighlightCurrentLine for similar highlighting, but for the current line, not the current column.
* CrosshairHighlighting for ways to highlight the current line and the current column at the same time.
* ChangingCursorDynamically for a way to change the cursor type when Emacs is idle, making it more visible.
* ModeLinePosition for a way to highlight the column number in the mode-line when the cursor is past some limit column you set.
* VlineMode for another way to highlight the current column.
* FindLongLines for how to find the longest lines (so you can shorten them).


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CategoryEditing
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