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[emacs.git] / lisp / hl-line.el
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1 ;;; hl-line.el --- highlight the current line
3 ;; Copyright (C) 1998, 2000, 2001, 2002, 2003, 2004,
4 ;; 2005, 2006 Free Software Foundation, Inc.
6 ;; Author: Dave Love <fx@gnu.org>
7 ;; Maintainer: FSF
8 ;; Created: 1998-09-13
9 ;; Keywords: faces, frames, emulation
11 ;; This file is part of GNU Emacs.
13 ;; GNU Emacs is free software; you can redistribute it and/or modify
14 ;; it under the terms of the GNU General Public License as published by
15 ;; the Free Software Foundation; either version 2, or (at your option)
16 ;; any later version.
18 ;; GNU Emacs is distributed in the hope that it will be useful,
19 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
20 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 ;; GNU General Public License for more details.
23 ;; You should have received a copy of the GNU General Public License
24 ;; along with GNU Emacs; see the file COPYING. If not, write to the
25 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
26 ;; Boston, MA 02110-1301, USA.
28 ;;; Commentary:
30 ;; Provides a local minor mode (toggled by M-x hl-line-mode) and
31 ;; a global minor mode (toggled by M-x global-hl-line-mode) to
32 ;; highlight, on a suitable terminal, the line on which point is. The
33 ;; global mode highlights the current line in the selected window only
34 ;; (except when the minibuffer window is selected). This was
35 ;; implemented to satisfy a request for a feature of Lesser Editors.
36 ;; The local mode is sticky: it highlights the line about the buffer's
37 ;; point even if the buffer's window is not selected. Caveat: the
38 ;; buffer's point might be different from the point of a non-selected
39 ;; window. Set the variable `hl-line-sticky-flag' to nil to make the
40 ;; local mode behave like the global mode.
42 ;; You probably don't really want to use the global mode; if the
43 ;; cursor is difficult to spot, try changing its colour, relying on
44 ;; `blink-cursor-mode' or both. The hookery used might affect
45 ;; response noticeably on a slow machine. The local mode may be
46 ;; useful in non-editing buffers such as Gnus or PCL-CVS though.
48 ;; An overlay is used. In the non-sticky cases, this overlay is
49 ;; active only on the selected window. A hook is added to
50 ;; `post-command-hook' to activate the overlay and move it to the line
51 ;; about point. To get the non-sticky behavior, `hl-line-unhighlight'
52 ;; is added to `pre-command-hook' as well. This function deactivates
53 ;; the overlay unconditionally in case the command changes the
54 ;; selected window. (It does so rather than keeping track of changes
55 ;; in the selected window).
57 ;; You could make variable `global-hl-line-mode' buffer-local and set
58 ;; it to nil to avoid highlighting specific buffers, when the global
59 ;; mode is used.
61 ;; By default the whole line is highlighted. The range of highlighting
62 ;; can be changed by defining an appropriate function as the
63 ;; buffer-local value of `hl-line-range-function'.
65 ;;; Code:
67 (defvar hl-line-overlay nil
68 "Overlay used by Hl-Line mode to highlight the current line.")
69 (make-variable-buffer-local 'hl-line-overlay)
71 (defvar global-hl-line-overlay nil
72 "Overlay used by Global-Hl-Line mode to highlight the current line.")
74 (defgroup hl-line nil
75 "Highlight the current line."
76 :version "21.1"
77 :group 'editing)
79 (defface hl-line
80 '((t :inherit highlight))
81 "Default face for highlighting the current line in Hl-Line mode."
82 :version "22.1"
83 :group 'hl-line)
85 (defcustom hl-line-face 'hl-line
86 "Face with which to highlight the current line in Hl-Line mode."
87 :type 'face
88 :group 'hl-line
89 :set (lambda (symbol value)
90 (set symbol value)
91 (dolist (buffer (buffer-list))
92 (with-current-buffer buffer
93 (when hl-line-overlay
94 (overlay-put hl-line-overlay 'face hl-line-face))))
95 (when global-hl-line-overlay
96 (overlay-put global-hl-line-overlay 'face hl-line-face))))
98 (defcustom hl-line-sticky-flag t
99 "*Non-nil means highlight the current line in all windows.
100 Otherwise Hl-Line mode will highlight only in the selected
101 window. Setting this variable takes effect the next time you use
102 the command `hl-line-mode' to turn Hl-Line mode on."
103 :type 'boolean
104 :version "22.1"
105 :group 'hl-line)
107 (defvar hl-line-range-function nil
108 "If non-nil, function to call to return highlight range.
109 The function of no args should return a cons cell; its car value
110 is the beginning position of highlight and its cdr value is the
111 end position of highlight in the buffer.
112 It should return nil if there's no region to be highlighted.
114 This variable is expected to be made buffer-local by modes.")
116 ;;;###autoload
117 (define-minor-mode hl-line-mode
118 "Buffer-local minor mode to highlight the line about point.
119 With ARG, turn Hl-Line mode on if ARG is positive, off otherwise.
121 If `hl-line-sticky-flag' is non-nil, Hl-Line mode highlights the
122 line about the buffer's point in all windows. Caveat: the
123 buffer's point might be different from the point of a
124 non-selected window. Hl-Line mode uses the function
125 `hl-line-highlight' on `post-command-hook' in this case.
127 When `hl-line-sticky-flag' is nil, Hl-Line mode highlights the
128 line about point in the selected window only. In this case, it
129 uses the function `hl-line-unhighlight' on `pre-command-hook' in
130 addition to `hl-line-highlight' on `post-command-hook'."
131 :group 'hl-line
132 (if hl-line-mode
133 (progn
134 ;; In case `kill-all-local-variables' is called.
135 (add-hook 'change-major-mode-hook #'hl-line-unhighlight nil t)
136 (if hl-line-sticky-flag
137 (remove-hook 'pre-command-hook #'hl-line-unhighlight t)
138 (add-hook 'pre-command-hook #'hl-line-unhighlight nil t))
139 (hl-line-highlight)
140 (add-hook 'post-command-hook #'hl-line-highlight nil t))
141 (remove-hook 'post-command-hook #'hl-line-highlight t)
142 (hl-line-unhighlight)
143 (remove-hook 'change-major-mode-hook #'hl-line-unhighlight t)
144 (remove-hook 'pre-command-hook #'hl-line-unhighlight t)))
146 (defun hl-line-highlight ()
147 "Activate the Hl-Line overlay on the current line."
148 (if hl-line-mode ; Might be changed outside the mode function.
149 (progn
150 (unless hl-line-overlay
151 (setq hl-line-overlay (make-overlay 1 1)) ; to be moved
152 (overlay-put hl-line-overlay 'face hl-line-face))
153 (overlay-put hl-line-overlay
154 'window (unless hl-line-sticky-flag (selected-window)))
155 (hl-line-move hl-line-overlay))
156 (hl-line-unhighlight)))
158 (defun hl-line-unhighlight ()
159 "Deactivate the Hl-Line overlay on the current line."
160 (if hl-line-overlay
161 (delete-overlay hl-line-overlay)))
163 ;;;###autoload
164 (define-minor-mode global-hl-line-mode
165 "Global minor mode to highlight the line about point in the current window.
166 With ARG, turn Global-Hl-Line mode on if ARG is positive, off otherwise.
168 Global-Hl-Line mode uses the functions `global-hl-line-unhighlight' and
169 `global-hl-line-highlight' on `pre-command-hook' and `post-command-hook'."
170 :global t
171 :group 'hl-line
172 (if global-hl-line-mode
173 (progn
174 (add-hook 'pre-command-hook #'global-hl-line-unhighlight)
175 (add-hook 'post-command-hook #'global-hl-line-highlight))
176 (global-hl-line-unhighlight)
177 (remove-hook 'pre-command-hook #'global-hl-line-unhighlight)
178 (remove-hook 'post-command-hook #'global-hl-line-highlight)))
180 (defun global-hl-line-highlight ()
181 "Active the Global-Hl-Line overlay on the current line in the current window."
182 (when global-hl-line-mode ; Might be changed outside the mode function.
183 (unless (window-minibuffer-p (selected-window))
184 (unless global-hl-line-overlay
185 (setq global-hl-line-overlay (make-overlay 1 1)) ; to be moved
186 (overlay-put global-hl-line-overlay 'face hl-line-face))
187 (overlay-put global-hl-line-overlay 'window (selected-window))
188 (hl-line-move global-hl-line-overlay))))
190 (defun global-hl-line-unhighlight ()
191 "Deactivate the Global-Hl-Line overlay on the current line."
192 (if global-hl-line-overlay
193 (delete-overlay global-hl-line-overlay)))
195 (defun hl-line-move (overlay)
196 "Move the Hl-Line overlay.
197 If `hl-line-range-function' is non-nil, move the OVERLAY to the position
198 where the function returns. If `hl-line-range-function' is nil, fill
199 the line including the point by OVERLAY."
200 (let (tmp b e)
201 (if hl-line-range-function
202 (setq tmp (funcall hl-line-range-function)
203 b (car tmp)
204 e (cdr tmp))
205 (setq tmp t
206 b (line-beginning-position)
207 e (line-beginning-position 2)))
208 (if tmp
209 (move-overlay overlay b e)
210 (move-overlay overlay 1 1))))
212 (provide 'hl-line)
214 ;;; arch-tag: ac806940-0876-4959-8c89-947563ee2833
215 ;;; hl-line.el ends here