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[emacs.git] / lisp / mwheel.el
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1 ;;; mwheel.el --- Wheel mouse support
3 ;; Copyright (C) 1998,2000,2001,2002 Free Software Foundation, Inc.
4 ;; Maintainer: William M. Perry <wmperry@gnu.org>
5 ;; Keywords: mouse
7 ;; This file is part of GNU Emacs.
9 ;; GNU Emacs 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.
14 ;; GNU Emacs 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.
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.
24 ;;; Commentary:
26 ;; This code will enable the use of the infamous 'wheel' on the new
27 ;; crop of mice. Under XFree86 and the XSuSE X Servers, the wheel
28 ;; events are sent as button4/button5 events.
30 ;; I for one would prefer some way of converting the button4/button5
31 ;; events into different event types, like 'mwheel-up' or
32 ;; 'mwheel-down', but I cannot find a way to do this very easily (or
33 ;; portably), so for now I just live with it.
35 ;; To enable this code, simply put this at the top of your .emacs
36 ;; file:
38 ;; (mwheel-install)
40 ;;; Code:
42 (require 'custom)
43 (require 'timer)
45 ;; Setter function for mouse-button user-options. Switch Mouse Wheel
46 ;; mode off and on again so that the old button is unbound and
47 ;; new button is bound to mwheel-scroll.
49 (defun mouse-wheel-change-button (var button)
50 (let ((active mouse-wheel-mode))
51 ;; Deactivate before changing the setting.
52 (when active (mouse-wheel-mode -1))
53 (set-default var button)
54 (when active (mouse-wheel-mode 1))))
56 (defvar mouse-wheel-down-button 4)
57 (make-obsolete-variable 'mouse-wheel-down-button
58 'mouse-wheel-down-event)
59 (defcustom mouse-wheel-down-event
60 ;; In the latest versions of XEmacs, we could just use mouse-%s as well.
61 (intern (format (if (featurep 'xemacs) "button%s" "mouse-%s")
62 mouse-wheel-down-button))
63 "Event used for scrolling down."
64 :group 'mouse
65 :type 'symbol
66 :set 'mouse-wheel-change-button)
68 (defvar mouse-wheel-up-button 5)
69 (make-obsolete-variable 'mouse-wheel-up-button
70 'mouse-wheel-up-event)
71 (defcustom mouse-wheel-up-event
72 ;; In the latest versions of XEmacs, we could just use mouse-%s as well.
73 (intern (format (if (featurep 'xemacs) "button%s" "mouse-%s")
74 mouse-wheel-up-button))
75 "Event used for scrolling down."
76 :group 'mouse
77 :type 'symbol
78 :set 'mouse-wheel-change-button)
80 (defvar mouse-wheel-click-button 2)
81 (make-obsolete-variable 'mouse-wheel-click-button
82 'mouse-wheel-click-event)
83 (defcustom mouse-wheel-click-event
84 ;; In the latest versions of XEmacs, we could just use mouse-%s as well.
85 (intern (format (if (featurep 'xemacs) "button%s" "mouse-%s")
86 mouse-wheel-click-button))
87 "Event that should be temporarily inhibited after mouse scrolling.
88 The mouse wheel is typically on the mouse-2 button, so it may easily
89 happen that text is accidentially yanked into the buffer when
90 scrolling with the mouse wheel. To prevent that, this variable can be
91 set to the event sent when clicking on the mouse wheel button."
92 :group 'mouse
93 :type 'symbol
94 :set 'mouse-wheel-change-button)
96 (defcustom mouse-wheel-inhibit-click-time 0.35
97 "Time in seconds to inhibit clicking on mouse wheel button after scroll."
98 :group 'mouse
99 :type 'number)
101 (defcustom mouse-wheel-scroll-amount '(5 ((shift) . 1) ((control) . nil))
102 "Amount to scroll windows by when spinning the mouse wheel.
103 This is an alist mapping the modifier key to the amount to scroll when
104 the wheel is moved with the modifier key depressed.
105 Elements of the list have the form (MODIFIERS . AMOUNT) or just AMOUNT if
106 MODIFIERS is nil.
108 AMOUNT should be the number of lines to scroll, or `nil' for near full
109 screen. It can also be a floating point number, specifying the fraction of
110 a full screen to scroll. A near full screen is `next-screen-context-lines'
111 less than a full screen."
112 :group 'mouse
113 :type '(cons
114 (choice :tag "Normal"
115 (const :tag "Full screen" :value nil)
116 (integer :tag "Specific # of lines")
117 (float :tag "Fraction of window")
118 (cons
119 (repeat (choice :tag "modifier"
120 (const alt) (const control) (const hyper)
121 (const meta) (const shift) (const super)))
122 (choice :tag "scroll amount"
123 (const :tag "Full screen" :value nil)
124 (integer :tag "Specific # of lines")
125 (float :tag "Fraction of window"))))
126 (repeat
127 (cons
128 (repeat (choice :tag "modifier"
129 (const alt) (const control) (const hyper)
130 (const meta) (const shift) (const super)))
131 (choice :tag "scroll amount"
132 (const :tag "Full screen" :value nil)
133 (integer :tag "Specific # of lines")
134 (float :tag "Fraction of window"))))))
136 (defcustom mouse-wheel-progessive-speed t
137 "If non-nil, the faster the user moves the wheel, the faster the scrolling.
138 Note that this has no effect when `mouse-wheel-scroll-amount' specifies
139 a \"near full screen\" scroll or when the mouse wheel sends key instead
140 of button events."
141 :group 'mouse
142 :type 'boolean)
144 (defcustom mouse-wheel-follow-mouse t
145 "Whether the mouse wheel should scroll the window that the mouse is over.
146 This can be slightly disconcerting, but some people prefer it."
147 :group 'mouse
148 :type 'boolean)
150 (if (not (fboundp 'event-button))
151 (defun mwheel-event-button (event)
152 (let ((x (event-basic-type event)))
153 ;; Map mouse-wheel events to appropriate buttons
154 (if (eq 'mouse-wheel x)
155 (let ((amount (car (cdr (cdr (cdr event))))))
156 (if (< amount 0)
157 mouse-wheel-up-event
158 mouse-wheel-down-event))
159 x)))
160 (fset 'mwheel-event-button 'event-button))
162 (if (not (fboundp 'event-window))
163 (defun mwheel-event-window (event)
164 (posn-window (event-start event)))
165 (fset 'mwheel-event-window 'event-window))
167 (defvar mwheel-inhibit-click-event-timer nil
168 "Timer running while mouse wheel click event is inhibited.")
170 (defun mwheel-inhibit-click-timeout ()
171 "Handler for `mwheel-inhibit-click-event-timer'."
172 (setq mwheel-inhibit-click-event-timer nil)
173 (remove-hook 'pre-command-hook 'mwheel-filter-click-events))
175 (defun mwheel-filter-click-events ()
176 "Discard `mouse-wheel-click-event' while scrolling the mouse."
177 (if (eq (event-basic-type last-input-event) mouse-wheel-click-event)
178 (setq this-command 'ignore)))
180 (defun mwheel-scroll (event)
181 "Scroll up or down according to the EVENT.
182 This should only be bound to mouse buttons 4 and 5."
183 (interactive (list last-input-event))
184 (let* ((curwin (if mouse-wheel-follow-mouse
185 (prog1
186 (selected-window)
187 (select-window (mwheel-event-window event)))))
188 (mods
189 (delq 'click (delq 'double (delq 'triple (event-modifiers event)))))
190 (amt (assoc mods mouse-wheel-scroll-amount)))
191 ;; Extract the actual amount or find the element that has no modifiers.
192 (if amt (setq amt (cdr amt))
193 (let ((list-elt mouse-wheel-scroll-amount))
194 (while (consp (setq amt (pop list-elt))))))
195 (if (floatp amt) (setq amt (1+ (truncate (* amt (window-height))))))
196 (when (and mouse-wheel-progessive-speed (numberp amt))
197 ;; When the double-mouse-N comes in, a mouse-N has been executed already,
198 ;; So by adding things up we get a squaring up (1, 3, 6, 10, 15, ...).
199 (setq amt (* amt (event-click-count event))))
200 (unwind-protect
201 (let ((button (mwheel-event-button event)))
202 (cond ((eq button mouse-wheel-down-event) (scroll-down amt))
203 ((eq button mouse-wheel-up-event) (scroll-up amt))
204 (t (error "Bad binding in mwheel-scroll"))))
205 (if curwin (select-window curwin))))
206 (when (and mouse-wheel-click-event mouse-wheel-inhibit-click-time)
207 (if mwheel-inhibit-click-event-timer
208 (cancel-timer mwheel-inhibit-click-event-timer)
209 (add-hook 'pre-command-hook 'mwheel-filter-click-events))
210 (setq mwheel-inhibit-click-event-timer
211 (run-with-timer mouse-wheel-inhibit-click-time nil
212 'mwheel-inhibit-click-timeout))))
214 ;;;###autoload
215 (define-minor-mode mouse-wheel-mode
216 "Toggle mouse wheel support.
217 With prefix argument ARG, turn on if positive, otherwise off.
218 Returns non-nil if the new state is enabled."
219 :global t
220 :group 'mouse
221 (let* ((dn mouse-wheel-down-event)
222 (up mouse-wheel-up-event)
223 (keys
224 (nconc (mapcar (lambda (amt) `[(,@(if (consp amt) (car amt)) ,up)])
225 mouse-wheel-scroll-amount)
226 (mapcar (lambda (amt) `[(,@(if (consp amt) (car amt)) ,dn)])
227 mouse-wheel-scroll-amount))))
228 ;; This condition-case is here because Emacs 19 will throw an error
229 ;; if you try to define a key that it does not know about. I for one
230 ;; prefer to just unconditionally do a mwheel-install in my .emacs, so
231 ;; that if the wheeled-mouse is there, it just works, and this way it
232 ;; doesn't yell at me if I'm on my laptop or another machine, etc.
233 (condition-case ()
234 (dolist (key keys)
235 (cond (mouse-wheel-mode
236 (global-set-key key 'mwheel-scroll))
237 ((eq (lookup-key (current-global-map) key) 'mwheel-scroll)
238 (global-unset-key key))))
239 (error nil))))
241 ;;; Compatibility entry point
242 ;;;###autoload
243 (defun mwheel-install (&optional uninstall)
244 "Enable mouse wheel support."
245 (mouse-wheel-mode (if uninstall -1 1)))
247 (provide 'mwheel)
249 ;;; mwheel.el ends here