lisp/mwheel.el

   1 ;;; mwheel.el --- Wheel mouse support
   2
   3 ;; Copyright (C) 1998, 2000, 2001, 2002, 2004  Free Software Foundation, Inc.
   4 ;; Maintainer: William M. Perry <wmperry@gnu.org>
   5 ;; Keywords: mouse
   6
   7 ;; This file is part of GNU Emacs.
   8
   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.
  13
  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.
  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 ;; 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.
  29
  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.
  34
  35 ;; To enable this code, simply put this at the top of your .emacs
  36 ;; file:
  37 ;;
  38 ;; (mouse-wheel-mode 1)
  39
  40 ;;; Code:
  41
  42 (require 'custom)
  43 (require 'timer)
  44
  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.
  48
  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))))
  55
  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   (if (memq window-system '(w32 mac))
  62       'wheel-up
  63     (intern (format (if (featurep 'xemacs) "button%s" "mouse-%s")
  64                     mouse-wheel-down-button)))
  65   "Event used for scrolling down."
  66   :group 'mouse
  67   :type 'symbol
  68   :set 'mouse-wheel-change-button)
  69
  70 (defvar mouse-wheel-up-button 5)
  71 (make-obsolete-variable 'mouse-wheel-up-button
  72                         'mouse-wheel-up-event)
  73 (defcustom mouse-wheel-up-event
  74   ;; In the latest versions of XEmacs, we could just use mouse-%s as well.
  75   (if (memq window-system '(w32 mac))
  76       'wheel-down
  77     (intern (format (if (featurep 'xemacs) "button%s" "mouse-%s")
  78                     mouse-wheel-up-button)))
  79   "Event used for scrolling down."
  80   :group 'mouse
  81   :type 'symbol
  82   :set 'mouse-wheel-change-button)
  83
  84 (defvar mouse-wheel-click-button 2)
  85 (make-obsolete-variable 'mouse-wheel-click-button
  86                         'mouse-wheel-click-event)
  87 (defcustom mouse-wheel-click-event
  88   ;; In the latest versions of XEmacs, we could just use mouse-%s as well.
  89   (intern (format (if (featurep 'xemacs) "button%s" "mouse-%s")
  90                   mouse-wheel-click-button))
  91   "Event that should be temporarily inhibited after mouse scrolling.
  92 The mouse wheel is typically on the mouse-2 button, so it may easily
  93 happen that text is accidentially yanked into the buffer when
  94 scrolling with the mouse wheel.  To prevent that, this variable can be
  95 set to the event sent when clicking on the mouse wheel button."
  96   :group 'mouse
  97   :type 'symbol
  98   :set 'mouse-wheel-change-button)
  99
 100 (defcustom mouse-wheel-inhibit-click-time 0.35
 101   "Time in seconds to inhibit clicking on mouse wheel button after scroll."
 102   :group 'mouse
 103   :type 'number)
 104
 105 (defcustom mouse-wheel-scroll-amount '(5 ((shift) . 1) ((control) . nil))
 106   "Amount to scroll windows by when spinning the mouse wheel.
 107 This is an alist mapping the modifier key to the amount to scroll when
 108 the wheel is moved with the modifier key depressed.
 109 Elements of the list have the form (MODIFIERS . AMOUNT) or just AMOUNT if
 110 MODIFIERS is nil.
 111
 112 AMOUNT should be the number of lines to scroll, or nil for near full
 113 screen.  It can also be a floating point number, specifying the fraction of
 114 a full screen to scroll.  A near full screen is `next-screen-context-lines'
 115 less than a full screen."
 116   :group 'mouse
 117   :type '(cons
 118           (choice :tag "Normal"
 119                   (const :tag "Full screen" :value nil)
 120                   (integer :tag "Specific # of lines")
 121                   (float :tag "Fraction of window")
 122                   (cons
 123                    (repeat (choice :tag "modifier"
 124                                    (const alt) (const control) (const hyper)
 125                                    (const meta) (const shift) (const super)))
 126                    (choice :tag "scroll amount"
 127                            (const :tag "Full screen" :value nil)
 128                            (integer :tag "Specific # of lines")
 129                            (float :tag "Fraction of window"))))
 130           (repeat
 131            (cons
 132             (repeat (choice :tag "modifier"
 133                             (const alt) (const control) (const hyper)
 134                             (const meta) (const shift) (const super)))
 135             (choice :tag "scroll amount"
 136                     (const :tag "Full screen" :value nil)
 137                     (integer :tag "Specific # of lines")
 138                     (float :tag "Fraction of window"))))))
 139
 140 (defcustom mouse-wheel-progressive-speed t
 141   "If non-nil, the faster the user moves the wheel, the faster the scrolling.
 142 Note that this has no effect when `mouse-wheel-scroll-amount' specifies
 143 a \"near full screen\" scroll or when the mouse wheel sends key instead
 144 of button events."
 145   :group 'mouse
 146   :type 'boolean)
 147
 148 (defcustom mouse-wheel-follow-mouse t
 149   "Whether the mouse wheel should scroll the window that the mouse is over.
 150 This can be slightly disconcerting, but some people prefer it."
 151   :group 'mouse
 152   :type 'boolean)
 153
 154 (if (not (fboundp 'event-button))
 155     (defun mwheel-event-button (event)
 156       (let ((x (event-basic-type event)))
 157         ;; Map mouse-wheel events to appropriate buttons
 158         (if (eq 'mouse-wheel x)
 159             (let ((amount (car (cdr (cdr (cdr event))))))
 160               (if (< amount 0)
 161                   mouse-wheel-up-event
 162                 mouse-wheel-down-event))
 163           x)))
 164   (fset 'mwheel-event-button 'event-button))
 165
 166 (if (not (fboundp 'event-window))
 167     (defun mwheel-event-window (event)
 168       (posn-window (event-start event)))
 169   (fset 'mwheel-event-window 'event-window))
 170
 171 (defvar mwheel-inhibit-click-event-timer nil
 172   "Timer running while mouse wheel click event is inhibited.")
 173
 174 (defun mwheel-inhibit-click-timeout ()
 175   "Handler for `mwheel-inhibit-click-event-timer'."
 176   (setq mwheel-inhibit-click-event-timer nil)
 177   (remove-hook 'pre-command-hook 'mwheel-filter-click-events))
 178
 179 (defun mwheel-filter-click-events ()
 180   "Discard `mouse-wheel-click-event' while scrolling the mouse."
 181   (if (eq (event-basic-type last-input-event) mouse-wheel-click-event)
 182       (setq this-command 'ignore)))
 183
 184 (defun mwheel-scroll (event)
 185   "Scroll up or down according to the EVENT.
 186 This should only be bound to mouse buttons 4 and 5."
 187   (interactive (list last-input-event))
 188   (let* ((curwin (if mouse-wheel-follow-mouse
 189                      (prog1
 190                          (selected-window)
 191                        (select-window (mwheel-event-window event)))))
 192          (mods
 193           (delq 'click (delq 'double (delq 'triple (event-modifiers event)))))
 194          (amt (assoc mods mouse-wheel-scroll-amount)))
 195     ;; Extract the actual amount or find the element that has no modifiers.
 196     (if amt (setq amt (cdr amt))
 197       (let ((list-elt mouse-wheel-scroll-amount))
 198         (while (consp (setq amt (pop list-elt))))))
 199     (if (floatp amt) (setq amt (1+ (truncate (* amt (window-height))))))
 200     (when (and mouse-wheel-progressive-speed (numberp amt))
 201       ;; When the double-mouse-N comes in, a mouse-N has been executed already,
 202       ;; So by adding things up we get a squaring up (1, 3, 6, 10, 15, ...).
 203       (setq amt (* amt (event-click-count event))))
 204     (unwind-protect
 205         (let ((button (mwheel-event-button event)))
 206           (cond ((eq button mouse-wheel-down-event) (scroll-down amt))
 207                 ((eq button mouse-wheel-up-event) (scroll-up amt))
 208                 (t (error "Bad binding in mwheel-scroll"))))
 209       (if curwin (select-window curwin))))
 210   (when (and mouse-wheel-click-event mouse-wheel-inhibit-click-time)
 211     (if mwheel-inhibit-click-event-timer
 212         (cancel-timer mwheel-inhibit-click-event-timer)
 213       (add-hook 'pre-command-hook 'mwheel-filter-click-events))
 214     (setq mwheel-inhibit-click-event-timer
 215           (run-with-timer mouse-wheel-inhibit-click-time nil
 216                           'mwheel-inhibit-click-timeout))))
 217
 218 ;;;###autoload
 219 (define-minor-mode mouse-wheel-mode
 220   "Toggle mouse wheel support.
 221 With prefix argument ARG, turn on if positive, otherwise off.
 222 Returns non-nil if the new state is enabled."
 223   :global t
 224   :group 'mouse
 225   (let* ((dn mouse-wheel-down-event)
 226          (up mouse-wheel-up-event)
 227          (keys
 228           (nconc (mapcar (lambda (amt) `[(,@(if (consp amt) (car amt)) ,up)])
 229                          mouse-wheel-scroll-amount)
 230                  (mapcar (lambda (amt) `[(,@(if (consp amt) (car amt)) ,dn)])
 231                          mouse-wheel-scroll-amount))))
 232     ;; This condition-case is here because Emacs 19 will throw an error
 233     ;; if you try to define a key that it does not know about.  I for one
 234     ;; prefer to just unconditionally do a mwheel-install in my .emacs, so
 235     ;; that if the wheeled-mouse is there, it just works, and this way it
 236     ;; doesn't yell at me if I'm on my laptop or another machine, etc.
 237     (condition-case ()
 238         (dolist (key keys)
 239           (cond (mouse-wheel-mode
 240                  (global-set-key key 'mwheel-scroll))
 241                 ((eq (lookup-key (current-global-map) key) 'mwheel-scroll)
 242                  (global-unset-key key))))
 243       (error nil))))
 244
 245 ;;; Compatibility entry point
 246 ;;;###autoload
 247 (defun mwheel-install (&optional uninstall)
 248   "Enable mouse wheel support."
 249   (mouse-wheel-mode (if uninstall -1 1)))
 250
 251 (provide 'mwheel)
 252
 253 ;; arch-tag: 50ed00e7-3686-4b7a-8037-fb31aa5c237f
 254 ;;; mwheel.el ends here