Initial import from perry

lisp/mwheel.el

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+;;; mwheel.el --- Mouse support for MS intelli-mouse type mice
+
+;; Copyright (C) 1998, Free Software Foundation, Inc.
+;; Maintainer: William M. Perry <wmperry@gnu.org>
+;; Keywords: mouse
+
+;; This file is part of Emacs.
+
+;; XEmacs is free software; you can redistribute it and/or modify it
+;; under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 2, or (at your option)
+;; any later version.
+
+;; XEmacs is distributed in the hope that it will be useful, but
+;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+;; General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with XEmacs; see the file COPYING.  If not, write to the 
+;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+;; Boston, MA 02111-1307, USA.
+
+;;; Synched up with: Not synched.
+
+;;; Commentary:
+
+;; This code will enable the use of the infamous 'wheel' on the new
+;; crop of mice.  Under XFree86 and the XSuSE X Servers, the wheel
+;; events are sent as button4/button5 events.
+
+;; I for one would prefer some way of converting the button4/button5
+;; events into different event types, like 'mwheel-up' or
+;; 'mwheel-down', but I cannot find a way to do this very easily (or
+;; portably), so for now I just live with it.
+
+;; To enable this code, simply put this at the top of your .emacs
+;; file:
+;;
+;; (autoload 'mwheel-install "mwheel" "Enable mouse wheel support.")
+;; (mwheel-install)
+
+;;; Code:
+
+(require 'custom)
+(require 'cl)
+
+(defcustom mwheel-scroll-amount '(5 . 1)
+  "Amount to scroll windows by when spinning the mouse wheel.
+This is actually a cons cell, where the first item is the amount to scroll
+on a normal wheel event, and the second is the amount to scroll when the
+wheel is moved with the shift key depressed.
+
+Each item should be the number of lines to scroll, or `nil' for near
+full screen.
+A near full screen is `next-screen-context-lines' less than a full screen."
+  :group 'mouse
+  :type '(cons
+	  (choice :tag "Normal"
+		  (const :tag "Full screen" :value nil)
+		  (integer :tag "Specific # of lines"))
+	  (choice :tag "Shifted"
+		  (const :tag "Full screen" :value nil)
+		  (integer :tag "Specific # of lines"))))
+
+(defcustom mwheel-follow-mouse nil
+  "Whether the mouse wheel should scroll the window that the mouse is over.
+This can be slightly disconcerting, but some people may prefer it."
+  :group 'mouse
+  :type 'boolean)
+
+(if (not (fboundp 'event-button))
+    (defun mwheel-event-button (event)
+      (let ((x (symbol-name (event-basic-type event))))
+	(if (not (string-match "^mouse-\\([0-9]+\\)" x))
+	    (error "Not a button event: %S" event))
+	(string-to-int (substring x (match-beginning 1) (match-end 1)))))
+  (fset 'mwheel-event-button 'event-button))
+
+(if (not (fboundp 'event-window))
+    (defun mwheel-event-window (event)
+      (posn-window (event-start event)))
+  (fset 'mwheel-event-window 'event-window))
+
+(defun mwheel-scroll (event)
+  (interactive "e")
+  (let ((curwin (if mwheel-follow-mouse
+		    (prog1
+			(selected-window)
+		      (select-window (mwheel-event-window event)))))
+	(amt (if (memq 'shift (event-modifiers event))
+		 (cdr mwheel-scroll-amount)
+	       (car mwheel-scroll-amount))))
+    (unwind-protect
+	(case (mwheel-event-button event)
+	  (4 (scroll-down amt))
+	  (5 (scroll-up amt))
+	  (otherwise (error "Bad binding in mwheel-scroll")))
+      (if curwin (select-window curwin)))))
+
+;;;###autoload
+(defun mwheel-install ()
+  "Enable mouse wheel support."
+  ;; In the latest versions of XEmacs, we could just use
+  ;; (S-)*mouse-[45], since those are aliases for the button
+  ;; equivalents in XEmacs, but I want this to work in as many
+  ;; versions of XEmacs as it can.
+  (let* ((mwheel-running-xemacs (string-match "XEmacs" (emacs-version)))
+	 (keys (if mwheel-running-xemacs
+		   '(button4 [(shift button4)] button5 [(shift button5)])
+		 '([mouse-4] [S-mouse-4] [mouse-5] [S-mouse-5]))))
+    ;; This condition-case is here because Emacs 19 will throw an error
+    ;; if you try to define a key that it does not know about.  I for one
+    ;; prefer to just unconditionally do a mwheel-install in my .emacs, so
+    ;; that if the wheeled-mouse is there, it just works, and this way it
+    ;; doesn't yell at me if I'm on my laptop or another machine, etc.
+    (condition-case ()
+	(while keys
+	  (define-key global-map (car keys) 'mwheel-scroll)
+	  (setq keys (cdr keys)))
+      (error nil))))
+    
+(provide 'mwheel)
+
+;;; mwheel.el ends here