1;;; xt-mouse.el --- support the mouse when emacs run in an xterm
2
3;; Copyright (C) 1994, 2000, 2001, 2002, 2003,
4;;   2004, 2005, 2006, 2007 Free Software Foundation, Inc.
5
6;; Author: Per Abrahamsen <abraham@dina.kvl.dk>
7;; Keywords: mouse, terminals
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
28;; Enable mouse support when running inside an xterm.
29
30;; This is actually useful when you are running X11 locally, but is
31;; working on remote machine over a modem line or through a gateway.
32
33;; It works by translating xterm escape codes into generic emacs mouse
34;; events so it should work with any package that uses the mouse.
35
36;; You don't have to turn off xterm mode to use the normal xterm mouse
37;; functionality, it is still available by holding down the SHIFT key
38;; when you press the mouse button.
39
40;;; Todo:
41
42;; Support multi-click -- somehow.
43
44;;; Code:
45
46(define-key function-key-map "\e[M" 'xterm-mouse-translate)
47
48(defvar xterm-mouse-last)
49
50;; Mouse events symbols must have an 'event-kind property with
51;; the value 'mouse-click.
52(dolist (event-type '(mouse-1 mouse-2 mouse-3
53			      M-down-mouse-1 M-down-mouse-2 M-down-mouse-3))
54  (put event-type 'event-kind 'mouse-click))
55
56(defun xterm-mouse-translate (event)
57  "Read a click and release event from XTerm."
58  (save-excursion
59    (save-window-excursion
60      (deactivate-mark)
61      (let* ((xterm-mouse-last)
62	     (down (xterm-mouse-event))
63	     (down-command (nth 0 down))
64	     (down-data (nth 1 down))
65	     (down-where (nth 1 down-data))
66	     (down-binding (key-binding (if (symbolp down-where)
67					    (vector down-where down-command)
68					  (vector down-command))))
69	     (is-click (string-match "^mouse" (symbol-name (car down)))))
70
71	(unless is-click
72	  (unless (and (eq (read-char) ?\e)
73		       (eq (read-char) ?\[)
74		       (eq (read-char) ?M))
75	    (error "Unexpected escape sequence from XTerm")))
76
77	(let* ((click (if is-click down (xterm-mouse-event)))
78	       (click-command (nth 0 click))
79	       (click-data (nth 1 click))
80	       (click-where (nth 1 click-data)))
81	  (if (memq down-binding '(nil ignore))
82	      (if (and (symbolp click-where)
83		       (consp click-where))
84		  (vector (list click-where click-data) click)
85		(vector click))
86	    (setq unread-command-events
87		  (if (eq down-where click-where)
88		      (list click)
89		    (list
90		     ;; Cheat `mouse-drag-region' with move event.
91		     (list 'mouse-movement click-data)
92		     ;; Generate a drag event.
93		     (if (symbolp down-where)
94			 0
95		       (list (intern (format "drag-mouse-%d"
96					     (+ 1 xterm-mouse-last)))
97			     down-data click-data)))))
98	    (if (and (symbolp down-where)
99		     (consp down-where))
100		(vector (list down-where down-data) down)
101	      (vector down))))))))
102
103(defvar xterm-mouse-x 0
104  "Position of last xterm mouse event relative to the frame.")
105
106(defvar xterm-mouse-y 0
107  "Position of last xterm mouse event relative to the frame.")
108
109(defvar xt-mouse-epoch nil)
110
111;; Indicator for the xterm-mouse mode.
112
113(defun xterm-mouse-position-function (pos)
114  "Bound to `mouse-position-function' in XTerm mouse mode."
115  (setcdr pos (cons xterm-mouse-x xterm-mouse-y))
116  pos)
117
118;; read xterm sequences above ascii 127 (#x7f)
119(defun xterm-mouse-event-read ()
120  (let ((c (read-char)))
121    (if (< c 0)
122        (+ c #x8000000 128)
123      c)))
124
125(defun xterm-mouse-truncate-wrap (f)
126  "Truncate with wrap-around."
127  (condition-case nil
128      ;; First try the built-in truncate, in case there's no overflow.
129      (truncate f)
130    ;; In case of overflow, do wraparound by hand.
131    (range-error
132     ;; In our case, we wrap around every 3 days or so, so if we assume
133     ;; a maximum of 65536 wraparounds, we're safe for a couple years.
134     ;; Using a power of 2 makes rounding errors less likely.
135     (let* ((maxwrap (* 65536 2048))
136            (dbig (truncate (/ f maxwrap)))
137            (fdiff (- f (* 1.0 maxwrap dbig))))
138       (+ (truncate fdiff) (* maxwrap dbig))))))
139
140
141(defun xterm-mouse-event ()
142  "Convert XTerm mouse event to Emacs mouse event."
143  (let* ((type (- (xterm-mouse-event-read) #o40))
144	 (x (- (xterm-mouse-event-read) #o40 1))
145	 (y (- (xterm-mouse-event-read) #o40 1))
146	 ;; Emulate timestamp information.  This is accurate enough
147	 ;; for default value of mouse-1-click-follows-link (450msec).
148	 (timestamp (xterm-mouse-truncate-wrap
149		     (* 1000
150			(- (float-time)
151			   (or xt-mouse-epoch
152			       (setq xt-mouse-epoch (float-time)))))))
153	 (mouse (intern
154		 ;; For buttons > 3, the release-event looks
155		 ;; differently (see xc/programs/xterm/button.c,
156		 ;; function EditorButton), and there seems to come in
157		 ;; a release-event only, no down-event.
158		 (cond ((>= type 64)
159			(format "mouse-%d" (- type 60)))
160		       ((memq type '(8 9 10))
161			(setq xterm-mouse-last type)
162			(format "M-down-mouse-%d" (- type 7)))
163		       ((= type 11)
164			(format "mouse-%d" (- xterm-mouse-last 7)))
165		       ((= type 3)
166			(format "mouse-%d" (+ 1 xterm-mouse-last)))
167		       (t
168			(setq xterm-mouse-last type)
169			(format "down-mouse-%d" (+ 1 type))))))
170	 (w (window-at x y))
171         (ltrb (window-edges w))
172         (left (nth 0 ltrb))
173         (top (nth 1 ltrb)))
174
175    (setq xterm-mouse-x x
176	  xterm-mouse-y y)
177    (setq
178     last-input-event
179     (list mouse
180	   (let ((event (if w
181			    (posn-at-x-y (- x left) (- y top) w t)
182			  (append (list nil 'menu-bar)
183				  (nthcdr 2 (posn-at-x-y x y))))))
184	     (setcar (nthcdr 3 event) timestamp)
185	     event)))))
186
187;;;###autoload
188(define-minor-mode xterm-mouse-mode
189  "Toggle XTerm mouse mode.
190With prefix arg, turn XTerm mouse mode on iff arg is positive.
191
192Turn it on to use Emacs mouse commands, and off to use xterm mouse commands.
193This works in terminal emulators compatible with xterm.  It only
194works for simple uses of the mouse.  Basically, only non-modified
195single clicks are supported.  When turned on, the normal xterm
196mouse functionality for such clicks is still available by holding
197down the SHIFT key while pressing the mouse button."
198  :global t :group 'mouse
199  (if xterm-mouse-mode
200      ;; Turn it on
201      (unless window-system
202	(setq mouse-position-function #'xterm-mouse-position-function)
203	(turn-on-xterm-mouse-tracking))
204    ;; Turn it off
205    (turn-off-xterm-mouse-tracking 'force)
206    (setq mouse-position-function nil)))
207
208(defun turn-on-xterm-mouse-tracking ()
209  "Enable Emacs mouse tracking in xterm."
210  (if xterm-mouse-mode
211      (send-string-to-terminal "\e[?1000h")))
212
213(defun turn-off-xterm-mouse-tracking (&optional force)
214  "Disable Emacs mouse tracking in xterm."
215  (if (or force xterm-mouse-mode)
216      (send-string-to-terminal "\e[?1000l")))
217
218;; Restore normal mouse behaviour outside Emacs.
219(add-hook 'suspend-hook 'turn-off-xterm-mouse-tracking)
220(add-hook 'suspend-resume-hook 'turn-on-xterm-mouse-tracking)
221(add-hook 'kill-emacs-hook 'turn-off-xterm-mouse-tracking)
222
223(provide 'xt-mouse)
224
225;; arch-tag: 84962d4e-fae9-4c13-a9d7-ef4925a4ac03
226;;; xt-mouse.el ends here
227