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1 | ;;; hl-line.el --- highlight the current line |
2 | ||
3 | ;; Copyright (C) 1998 Free Software Foundation, Inc. | |
4 | ||
5 | ;; Author: Dave Love <fx@gnu.org> | |
6 | ;; Created: 1998-09-13 | |
7 | ;; Keywords: faces, frames | |
8 | ||
9 | ;; Hl-Line mode is free software; you can redistribute it and/or modify | |
10 | ;; it under the terms of the GNU General Public License as published by | |
11 | ;; the Free Software Foundation; either version 2, or (at your option) | |
12 | ;; any later version. | |
13 | ||
14 | ;; Hl-Line mode is distributed in the hope that it will be useful, | |
15 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | ;; GNU General Public License for more details. | |
18 | ||
19 | ;; You should have received a copy of the GNU General Public License | |
20 | ;; along with GNU Emacs; see the file COPYING. If not, write to the | |
21 | ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
22 | ;; Boston, MA 02111-1307, USA. | |
23 | ||
24 | ;;; Commentary: | |
25 | ||
26 | ;; Provides a global minor mode (toggled by M-x hl-line-mode) to | |
27 | ;; highlight, in a windowing system, the line on which point is | |
28 | ;; (except in a minibuffer window) to satisfy a request for a feature | |
29 | ;; of Lesser Editors. | |
30 | ||
31 | ;; You probably don't really want this; if the cursor is difficult to | |
32 | ;; spot, try changing its colour or using a cursor blinking | |
33 | ;; <URL:http://www.wonderworks.com/download/blinking-cursor.el.gz> or | |
34 | ;; jiggling <URL:http://www.eskimo.com/%7Eseldon> package. (Cursor | |
35 | ;; blinking will be built in to Emacs 21.) The hookery involved here | |
36 | ;; might slow Emacs noticeably on a slow machine. | |
37 | ||
38 | ;; An overlay is used, active only on the selected window. Hooks are | |
39 | ;; added to `pre-command-hook' and `post-command-hook' to activate and | |
40 | ;; deactivate (by deleting) the overlay. `hl-line-unhighlight', on | |
41 | ;; `pre-command-hook', deactivates it unconditionally in case the | |
42 | ;; command changes the selected window. (It does so rather than | |
43 | ;; keeping track of changes in the selected window). | |
44 | ;; `hl-line-highlight', on `post-command-hook', activates it again | |
45 | ;; across the window width. | |
46 | ||
47 | ;;; Code: | |
48 | ||
49 | (defgroup hl-line nil | |
50 | "Highliight the current line." | |
51 | :group 'editing) | |
52 | ||
53 | (defcustom hl-line-mode nil | |
54 | "Non-nil if Hl-Line mode is enabled." | |
55 | :set (lambda (symbol value) | |
56 | (hl-line-mode (or value 0))) | |
57 | :initialize 'custom-initialize-default | |
58 | :type 'boolean | |
59 | :group 'hl-line | |
60 | :require 'hl-line) | |
61 | ||
62 | (defcustom hl-line-face 'highlight | |
63 | "Face with which to highlight the current line." | |
64 | :type 'face | |
65 | :group 'hl-line) | |
66 | ||
67 | (defvar hl-line-overlay nil) | |
68 | (make-variable-buffer-local 'hl-line-overlay) | |
69 | ||
70 | (defun hl-line-highlight () | |
71 | "Active the Hl-Line overlay on the current line in the current window. | |
72 | \(Unless it's a minibuffer window.)" | |
73 | (unless (window-minibuffer-p (selected-window)) ; silly in minibuffer | |
74 | (unless hl-line-overlay ; new overlay for this buffer | |
75 | (setq hl-line-overlay (make-overlay 1 1)) ; to be moved | |
76 | (overlay-put hl-line-overlay 'face hl-line-face)) | |
77 | (overlay-put hl-line-overlay 'window (selected-window)) | |
78 | (move-overlay hl-line-overlay | |
79 | (line-beginning-position) (1+ (line-end-position))))) | |
80 | ||
81 | (defun hl-line-unhighlight () | |
82 | "Deactivate the Hl-Line overlay on the current line in the current window." | |
83 | (if hl-line-overlay | |
84 | (delete-overlay hl-line-overlay))) | |
85 | ||
86 | (defun hl-line-mode (&optional arg) | |
87 | "Global minor mode to highlight the line about point. | |
88 | ||
89 | With ARG, turn Hl-Line mode on if ARG is positive, off otherwise. | |
90 | Only useful with a windowing system. | |
91 | Uses functions `hl-line-unhighlight' and `hl-line-highlight' on | |
92 | `pre-command-hook' and `post-command-hook'." | |
93 | (interactive "P") | |
94 | (setq hl-line-mode (if (null arg) | |
95 | (not hl-line-mode) | |
96 | (> (prefix-numeric-value arg) 0))) | |
97 | (cond (hl-line-mode | |
98 | (add-hook 'pre-command-hook #'hl-line-unhighlight) | |
99 | (add-hook 'post-command-hook #'hl-line-highlight)) | |
100 | (t | |
101 | (hl-line-unhighlight) | |
102 | (remove-hook 'pre-command-hook #'hl-line-unhighlight) | |
103 | (remove-hook 'post-command-hook #'hl-line-highlight))) | |
104 | (if (interactive-p) | |
105 | (message "Hl-Line mode %sabled" (if hl-line-mode "en" "dis")))) | |
106 | ||
107 | (provide 'hl-line) | |
108 | ||
109 | ;;; hl-line.el ends here |