1;;; scroll-all.el --- scroll all buffers together minor mode
2
3;; Copyright (C) 1997, 2001, 2002, 2003, 2004, 2005,
4;;   2006, 2007 Free Software Foundation, Inc.
5
6;; Author: Gary D. Foster <Gary.Foster@corp.sun.com>
7;; Keywords: scroll crisp brief lock
8
9;; This file is part of GNU Emacs.
10
11;; GNU Emacs is free software; you can redistribute it and/or modify
12;; it under the terms of the GNU General Public License as published by
13;; the Free Software Foundation; either version 2, or (at your option)
14;; any later version.
15
16;; GNU Emacs is distributed in the hope that it will be useful,
17;; but WITHOUT ANY WARRANTY; without even the implied warranty of
18;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19;; GNU General Public License for more details.
20
21;; You should have received a copy of the GNU General Public License
22;; along with GNU Emacs; see the file COPYING.  If not, write to the
23;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
24;; Boston, MA 02110-1301, USA.
25
26;;; Commentary:
27;;    This mode allows multiple buffers to be 'locked' so that scrolling
28;;    up or down lines in any buffer causes all the buffers to mirror
29;;    the scrolling.  It hooks into the post-command-hook to check for
30;;    potential scrolling commands and if we're locked, mirrors them in all
31;;    windows.  This allows us to grab line-at-a-time scrolling as well as
32;;    screen-at-a-time scrolling, and doesn't remap any of the keyboard
33;;    commands to do it.
34
35;; You can enable and disable this mode with the 'scroll-all-mode' command.
36
37;; Suggestions/ideas from:
38;;    Rick Macdonald <rickm@vsl.com>
39;;    Anders Lindgren <andersl@csd.uu.se>
40
41;;; Code:
42
43(defun scroll-all-function-all (func arg)
44  "Apply function FUNC with argument ARG to all visible windows."
45  (let ((num-windows (count-windows))
46	(count 1))
47    (when (> num-windows 1)
48      (other-window 1)
49      (while (< count num-windows)
50	(condition-case nil
51	    (funcall func arg)
52	  ;; Ignore beginning- or end-of-buffer error in other windows.
53	  (error nil)
54	  )
55	(other-window 1)
56	(setq count (1+ count))))))
57
58(defun scroll-all-scroll-down-all (arg)
59  "Scroll down in all visible windows."
60  (interactive "p")
61  (scroll-all-function-all 'next-line arg))
62
63(defun scroll-all-scroll-up-all (arg)
64  "Scroll up in all visible windows."
65  (interactive "p")
66  (scroll-all-function-all 'previous-line arg))
67
68(defun scroll-all-page-down-all (arg)
69  "Page down in all visible windows."
70  (interactive "P")
71  (scroll-all-function-all 'scroll-up arg))
72
73(defun scroll-all-page-up-all (arg)
74  "Page up in all visible windows."
75  (interactive "P")
76  (scroll-all-function-all 'scroll-down arg))
77
78(defun scroll-all-beginning-of-buffer-all (arg)
79  "Go to the beginning of the buffer in all visible windows."
80  (interactive "P")
81  (scroll-all-function-all 'beginning-of-buffer arg))
82
83(defun scroll-all-end-of-buffer-all (arg)
84  "Go to the end of the buffer in all visible windows."
85  (interactive "P")
86  (scroll-all-function-all 'end-of-buffer arg))
87
88
89(defun scroll-all-check-to-scroll ()
90  "Check `this-command' to see if a scroll is to be done."
91  (cond ((eq this-command 'next-line)
92	 (call-interactively 'scroll-all-scroll-down-all))
93	((eq this-command 'previous-line)
94	 (call-interactively 'scroll-all-scroll-up-all))
95	((eq this-command 'scroll-up)
96	 (call-interactively 'scroll-all-page-down-all))
97	((eq this-command 'scroll-down)
98	 (call-interactively 'scroll-all-page-up-all))
99	((eq this-command 'beginning-of-buffer)
100	 (call-interactively 'scroll-all-beginning-of-buffer-all))
101	((eq this-command 'end-of-buffer)
102	 (call-interactively 'scroll-all-end-of-buffer-all))))
103
104
105;;;###autoload
106(define-minor-mode scroll-all-mode
107  "Toggle Scroll-All minor mode.
108With ARG, turn Scroll-All minor mode on if ARG is positive, off otherwise.
109When Scroll-All mode is on, scrolling commands entered in one window
110apply to all visible windows in the same frame."
111  nil " *SL*" nil
112  :global t
113  :group 'windows
114  :group 'scrolling
115  (if scroll-all-mode
116      (add-hook 'post-command-hook 'scroll-all-check-to-scroll)
117    (remove-hook 'post-command-hook 'scroll-all-check-to-scroll)))
118
119(provide 'scroll-all)
120
121;;; arch-tag: db20089a-b157-45df-b5d4-2430e60acdd8
122;;; scroll-all.el ends here
123