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092af6d8 RS |
1 | ;;; mouse-drag.el --- use mouse-2 to do a new style of scrolling |
2 | ||
f1ade7d3 | 3 | ;; Copyright (C) 1996, 1997, 2001 Free Software Foundation, Inc. |
84f19a49 | 4 | |
bc28b212 RS |
5 | ;; Author: John Heidemann <johnh@ISI.EDU> |
6 | ;; Keywords: mouse | |
84f19a49 RS |
7 | |
8 | ;; This file is part of GNU Emacs. | |
9 | ||
10 | ;; GNU Emacs is free software; you can redistribute it and/or modify | |
11 | ;; it under the terms of the GNU General Public License as published by | |
12 | ;; the Free Software Foundation; either version 2, or (at your option) | |
13 | ;; any later version. | |
14 | ||
15 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
16 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | ;; GNU General Public License for more details. | |
19 | ||
20 | ;; You should have received a copy of the GNU General Public License | |
21 | ;; along with GNU Emacs; see the file COPYING. If not, write to the | |
22 | ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
23 | ;; Boston, MA 02111-1307, USA. | |
24 | ||
25 | ;;; Commentary: | |
26 | ||
27 | ;;; What is ``mouse-drag.el''? | |
28 | ;;; | |
29 | ;;; Doesn't that scroll bar seem far away when you want to scroll? | |
30 | ;;; This module overloads mouse-2 to do ``throw'' scrolling. You | |
31 | ;;; click and drag. The distance you move from your original click | |
32 | ;;; turns into a scroll amount. The scroll amount is scaled | |
33 | ;;; exponentially to make both large moves and short adjustments easy. | |
34 | ;;; What this boils down to is that you can easily scroll around the | |
35 | ;;; buffer without much mouse movement. Finally, clicks which aren't | |
36 | ;;; drags are passed off to the old mouse-2 binding, so old mouse-2 | |
37 | ;;; operations (find-file in dired-mode, yanking in most other modes) | |
38 | ;;; still work. | |
39 | ;;; | |
40 | ;;; There is an alternative way to scroll, ``drag'' scrolling. You | |
41 | ;;; can click on a character and then drag it around, scrolling the | |
42 | ;;; buffer with you. The character always stays under the mouse. | |
43 | ;;; Compared to throw-scrolling, this approach provides direct | |
44 | ;;; manipulation (nice) but requires more mouse movement | |
45 | ;;; (unfortunate). It is offered as an alternative for those who | |
46 | ;;; prefer it. | |
47 | ;;; | |
48 | ;;; If you like mouse-drag, you should also check out mouse-copy | |
49 | ;;; for ``one-click text copy and move''. | |
50 | ;;; | |
51 | ;;; To use mouse-drag, place the following in your .emacs file: | |
52 | ;;; (require 'mouse-drag) | |
53 | ;;; -and either- | |
54 | ;;; (global-set-key [down-mouse-2] 'mouse-drag-throw) | |
55 | ;;; -or- | |
56 | ;;; (global-set-key [down-mouse-2] 'mouse-drag-drag) | |
57 | ;;; | |
58 | ;;; | |
59 | ;;; | |
60 | ;;; Options: | |
61 | ;;; | |
62 | ;;; - reverse the throw-scroll direction with \\[mouse-throw-with-scroll-bar] | |
63 | ;;; - work around a bug with \\[mouse-extras-work-around-drag-bug] | |
351d52f7 KH |
64 | ;;; - auto-enable horizontal scrolling with |
65 | ;;; \\[mouse-drag-electric-col-scrolling] | |
84f19a49 RS |
66 | ;;; |
67 | ;;; | |
68 | ;;; History and related work: | |
69 | ;;; | |
70 | ;;; One-click copying and moving was inspired by lemacs-19.8. | |
71 | ;;; Throw-scrolling was inspired by MacPaint's ``hand'' and by Tk's | |
72 | ;;; mouse-2 scrolling. The package mouse-scroll.el by Tom Wurgler | |
73 | ;;; <twurgler@goodyear.com> is similar to mouse-drag-throw, but | |
74 | ;;; doesn't pass clicks through. | |
75 | ;;; | |
76 | ;;; These functions have been tested in emacs version 19.30, | |
77 | ;;; and this package has run in the past on 19.25-19.29. | |
78 | ;;; | |
79 | ;;; Originally mouse-drag was part of a larger package. | |
80 | ;;; As of 11 July 96 the scrolling functions were split out | |
81 | ;;; in preparation for incorporation into (the future) emacs-19.32. | |
82 | ;;; | |
83 | ;;; | |
84 | ;;; Thanks: | |
85 | ;;; | |
86 | ;;; Thanks to Kai Grossjohann | |
87 | ;;; <grossjoh@dusty.informatik.uni-dortmund.de> for reporting bugs, to | |
88 | ;;; Tom Wurgler <twurgler@goodyear.com> for reporting bugs and | |
89 | ;;; suggesting fixes, and to Joel Graber <jgraber@ti.com> for | |
90 | ;;; prompting me to do drag-scrolling and for an initial | |
91 | ;;; implementation of horizontal drag-scrolling. | |
92 | ;;; | |
93 | ;;; -johnh@isi.edu, 11-Jul-96 | |
94 | ;;; | |
95 | ;;; | |
351d52f7 | 96 | ;;; What's new with mouse-drag 2.24? |
84f19a49 | 97 | ;;; |
351d52f7 KH |
98 | ;;; - mouse-drag-electric-col-scrolling (default: on) |
99 | ;;; auto-enables horizontal scrolling when clicks on wrapped | |
100 | ;;; lines occur | |
84f19a49 RS |
101 | \f |
102 | ;;; Code: | |
103 | ||
104 | ;; | |
105 | ;; scrolling code | |
106 | ;; | |
107 | ||
108 | (defun mouse-drag-safe-scroll (row-delta &optional col-delta) | |
8c398124 | 109 | "Scroll down ROW-DELTA lines and right COL-DELTA, ignoring buffer edge errors. |
84f19a49 | 110 | Keep the cursor on the screen as needed." |
f1ade7d3 GM |
111 | (let ((scroll-preserve-screen-position nil)) |
112 | (if (and row-delta | |
113 | (/= 0 row-delta)) | |
114 | (condition-case nil ;; catch and ignore movement errors | |
115 | (scroll-down row-delta) | |
116 | (beginning-of-buffer (message "Beginning of buffer")) | |
117 | (end-of-buffer (message "End of buffer")))) | |
118 | (if (and col-delta | |
119 | (/= 0 col-delta)) | |
120 | (progn | |
121 | (scroll-right col-delta) | |
122 | ;; Make sure that the point stays on the visible screen | |
123 | ;; (if truncation-lines in set). | |
124 | ;; This code mimics the behavior we automatically get | |
125 | ;; when doing vertical scrolling. | |
126 | ;; Problem identified and a fix suggested by Tom Wurgler. | |
127 | (cond | |
128 | ((< (current-column) (window-hscroll)) | |
129 | (move-to-column (window-hscroll))) ; make on left column | |
130 | ((> (- (current-column) (window-hscroll) (window-width) -2) 0) | |
131 | (move-to-column (+ (window-width) (window-hscroll) -3)))))))) | |
84f19a49 RS |
132 | |
133 | (defun mouse-drag-repeatedly-safe-scroll (row-delta &optional col-delta) | |
8c398124 | 134 | "Scroll ROW-DELTA rows and COL-DELTA cols until an event happens." |
84f19a49 RS |
135 | (while (sit-for mouse-scroll-delay) |
136 | (mouse-drag-safe-scroll row-delta col-delta))) | |
137 | ||
138 | (defun mouse-drag-events-are-point-events-p (start-posn end-posn) | |
8c398124 | 139 | "Determine if START-POSN and END-POSN are \"close\"." |
84f19a49 RS |
140 | (let* |
141 | ((start-col-row (posn-col-row start-posn)) | |
142 | (end-col-row (posn-col-row end-posn))) | |
143 | (and | |
144 | ;; We no longer exclude things by time. | |
145 | ;; (< (- (posn-timestamp end-posn) (posn-timestamp start-posn)) | |
146 | ;; (if (numberp double-click-time) | |
147 | ;; (* 2 double-click-time) ;; stretch it a little | |
148 | ;; 999999)) ;; non-numeric => check by position alone | |
149 | (= (car start-col-row) (car end-col-row)) | |
150 | (= (cdr start-col-row) (cdr end-col-row))))) | |
151 | ||
351d52f7 KH |
152 | (defvar mouse-drag-electric-col-scrolling t |
153 | "If non-nil, mouse-drag on a long line enables truncate-lines.") | |
154 | ||
84f19a49 | 155 | (defun mouse-drag-should-do-col-scrolling () |
8c398124 | 156 | "Determine if it's wise to enable col-scrolling for the current window. |
351d52f7 | 157 | Basically, we check for existing horizontal scrolling." |
84f19a49 RS |
158 | (or truncate-lines |
159 | (> (window-hscroll (selected-window)) 0) | |
f36782bc | 160 | (< (window-width) (frame-width)) |
351d52f7 KH |
161 | (and |
162 | mouse-drag-electric-col-scrolling | |
163 | (save-excursion ;; on a long line? | |
164 | (let | |
165 | ((beg (progn (beginning-of-line) (point))) | |
166 | (end (progn (end-of-line) (point)))) | |
167 | (if (> (- end beg) (window-width)) | |
168 | (setq truncate-lines t) | |
169 | nil)))))) | |
84f19a49 RS |
170 | |
171 | (defvar mouse-throw-with-scroll-bar nil | |
8c398124 | 172 | "*Set direction of mouse-throwing. |
84f19a49 RS |
173 | If nil, the text moves in the direction the mouse moves. |
174 | If t, the scroll bar moves in the direction the mouse moves.") | |
8c398124 | 175 | (defconst mouse-throw-magnifier-with-scroll-bar |
84f19a49 RS |
176 | [-16 -8 -4 -2 -1 0 0 0 1 2 4 8 16]) |
177 | (defconst mouse-throw-magnifier-with-mouse-movement | |
178 | [ 16 8 4 2 1 0 0 0 -1 -2 -4 -8 -16]) | |
179 | (defconst mouse-throw-magnifier-min -6) | |
180 | (defconst mouse-throw-magnifier-max 6) | |
181 | ||
182 | (defun mouse-drag-throw (start-event) | |
183 | "\"Throw\" the page according to a mouse drag. | |
184 | ||
185 | A \"throw\" is scrolling the page at a speed relative to the distance | |
186 | from the original mouse click to the current mouse location. Try it; | |
187 | you'll like it. It's easier to observe than to explain. | |
188 | ||
189 | If the mouse is clicked and released in the same place of time we | |
190 | assume that the user didn't want to scdebugroll but wanted to whatever | |
191 | mouse-2 used to do, so we pass it through. | |
192 | ||
193 | Throw scrolling was inspired (but is not identical to) the \"hand\" | |
194 | option in MacPaint, or the middle button in Tk text widgets. | |
195 | ||
196 | If `mouse-throw-with-scroll-bar' is non-nil, then this command scrolls | |
197 | in the opposite direction. (Different people have different ideas | |
198 | about which direction is natural. Perhaps it has to do with which | |
199 | hemisphere you're in.) | |
200 | ||
201 | To test this function, evaluate: | |
202 | (global-set-key [down-mouse-2] 'mouse-drag-throw)" | |
203 | (interactive "e") | |
204 | ;; we want to do save-selected-window, but that requires 19.29 | |
205 | (let* ((start-posn (event-start start-event)) | |
206 | (start-window (posn-window start-posn)) | |
207 | (start-row (cdr (posn-col-row start-posn))) | |
208 | (start-col (car (posn-col-row start-posn))) | |
209 | (old-selected-window (selected-window)) | |
210 | event end row mouse-delta scroll-delta | |
e35afc97 | 211 | have-scrolled |
84f19a49 RS |
212 | window-last-row |
213 | col mouse-col-delta window-last-col | |
214 | (scroll-col-delta 0) | |
215 | adjusted-mouse-col-delta | |
4ebeb09d | 216 | adjusted-mouse-delta |
84f19a49 RS |
217 | ;; be conservative about allowing horizontal scrolling |
218 | (col-scrolling-p (mouse-drag-should-do-col-scrolling))) | |
219 | (select-window start-window) | |
220 | (track-mouse | |
221 | (while (progn | |
222 | (setq event (read-event) | |
223 | end (event-end event) | |
224 | row (cdr (posn-col-row end)) | |
225 | col (car (posn-col-row end))) | |
226 | (or (mouse-movement-p event) | |
227 | (eq (car-safe event) 'switch-frame))) | |
228 | (if (eq start-window (posn-window end)) | |
229 | (progn | |
230 | (setq mouse-delta (- start-row row) | |
231 | adjusted-mouse-delta | |
232 | (- (cond | |
233 | ((<= mouse-delta mouse-throw-magnifier-min) | |
234 | mouse-throw-magnifier-min) | |
235 | ((>= mouse-delta mouse-throw-magnifier-max) | |
236 | mouse-throw-magnifier-max) | |
237 | (t mouse-delta)) | |
238 | mouse-throw-magnifier-min) | |
239 | scroll-delta (aref (if mouse-throw-with-scroll-bar | |
240 | mouse-throw-magnifier-with-scroll-bar | |
241 | mouse-throw-magnifier-with-mouse-movement) | |
242 | adjusted-mouse-delta)) | |
243 | (if col-scrolling-p | |
244 | (setq mouse-col-delta (- start-col col) | |
245 | adjusted-mouse-col-delta | |
246 | (- (cond | |
247 | ((<= mouse-col-delta mouse-throw-magnifier-min) | |
248 | mouse-throw-magnifier-min) | |
249 | ((>= mouse-col-delta mouse-throw-magnifier-max) | |
250 | mouse-throw-magnifier-max) | |
251 | (t mouse-col-delta)) | |
252 | mouse-throw-magnifier-min) | |
253 | scroll-col-delta (aref (if mouse-throw-with-scroll-bar | |
254 | mouse-throw-magnifier-with-scroll-bar | |
255 | mouse-throw-magnifier-with-mouse-movement) | |
256 | adjusted-mouse-col-delta))))) | |
257 | (if (or (/= 0 scroll-delta) | |
258 | (/= 0 scroll-col-delta)) | |
259 | (progn | |
260 | (setq have-scrolled t) | |
261 | (mouse-drag-safe-scroll scroll-delta scroll-col-delta) | |
262 | (mouse-drag-repeatedly-safe-scroll scroll-delta scroll-col-delta))))) ;xxx | |
263 | ;; If it was a click and not a drag, prepare to pass the event on. | |
e35afc97 | 264 | ;; Is there a more correct way to reconstruct the event? |
84f19a49 RS |
265 | (if (and (not have-scrolled) |
266 | (mouse-drag-events-are-point-events-p start-posn end)) | |
e35afc97 RS |
267 | (push (cons (event-basic-type start-event) (cdr start-event)) |
268 | unread-command-events)) | |
84f19a49 | 269 | ;; Now restore the old window. |
e35afc97 | 270 | (select-window old-selected-window))) |
84f19a49 RS |
271 | |
272 | (defun mouse-drag-drag (start-event) | |
273 | "\"Drag\" the page according to a mouse drag. | |
274 | ||
275 | Drag scrolling moves the page according to the movement of the mouse. | |
276 | You \"grab\" the character under the mouse and move it around. | |
277 | ||
278 | If the mouse is clicked and released in the same place of time we | |
279 | assume that the user didn't want to scroll but wanted to whatever | |
280 | mouse-2 used to do, so we pass it through. | |
281 | ||
282 | Drag scrolling is identical to the \"hand\" option in MacPaint, or the | |
283 | middle button in Tk text widgets. | |
284 | ||
285 | To test this function, evaluate: | |
286 | (global-set-key [down-mouse-2] 'mouse-drag-drag)" | |
287 | (interactive "e") | |
288 | ;; we want to do save-selected-window, but that requires 19.29 | |
289 | (let* ((start-posn (event-start start-event)) | |
290 | (start-window (posn-window start-posn)) | |
291 | (start-row (cdr (posn-col-row start-posn))) | |
292 | (start-col (car (posn-col-row start-posn))) | |
293 | (old-selected-window (selected-window)) | |
294 | event end row mouse-delta scroll-delta | |
e35afc97 | 295 | have-scrolled |
84f19a49 RS |
296 | window-last-row |
297 | col mouse-col-delta window-last-col | |
298 | (scroll-col-delta 0) | |
299 | ;; be conservative about allowing horizontal scrolling | |
300 | (col-scrolling-p (mouse-drag-should-do-col-scrolling))) | |
301 | (select-window start-window) | |
302 | (setq window-last-row (- (window-height) 2) | |
303 | window-last-col (- (window-width) 2)) | |
304 | (track-mouse | |
305 | (while (progn | |
306 | (setq event (read-event) | |
307 | end (event-end event) | |
308 | row (cdr (posn-col-row end)) | |
309 | col (car (posn-col-row end))) | |
310 | (or (mouse-movement-p event) | |
311 | (eq (car-safe event) 'switch-frame))) | |
312 | ;; Scroll if see if we're on the edge. | |
313 | ;; NEEDSWORK: should handle mouse-in-other window. | |
314 | (cond | |
315 | ((not (eq start-window (posn-window end))) | |
316 | t) ; wait for return to original window | |
317 | ((<= row 0) (mouse-drag-repeatedly-safe-scroll -1 0)) | |
318 | ((>= row window-last-row) (mouse-drag-repeatedly-safe-scroll 1 0)) | |
319 | ((and col-scrolling-p (<= col 1)) (mouse-drag-repeatedly-safe-scroll 0 -1)) | |
320 | ((and col-scrolling-p (>= col window-last-col)) (mouse-drag-repeatedly-safe-scroll 0 1)) | |
321 | (t | |
322 | (setq scroll-delta (- row start-row) | |
323 | start-row row) | |
324 | (if col-scrolling-p | |
325 | (setq scroll-col-delta (- col start-col) | |
326 | start-col col)) | |
327 | (if (or (/= 0 scroll-delta) | |
328 | (/= 0 scroll-col-delta)) | |
329 | (progn | |
330 | (setq have-scrolled t) | |
331 | (mouse-drag-safe-scroll scroll-delta scroll-col-delta))))))) | |
332 | ;; If it was a click and not a drag, prepare to pass the event on. | |
e35afc97 | 333 | ;; Is there a more correct way to reconstruct the event? |
84f19a49 RS |
334 | (if (and (not have-scrolled) |
335 | (mouse-drag-events-are-point-events-p start-posn end)) | |
e35afc97 RS |
336 | (push (cons (event-basic-type start-event) (cdr start-event)) |
337 | unread-command-events)) | |
84f19a49 | 338 | ;; Now restore the old window. |
e35afc97 RS |
339 | (select-window old-selected-window))) |
340 | ||
84f19a49 RS |
341 | |
342 | (provide 'mouse-drag) | |
343 | ||
ab5796a9 | 344 | ;;; arch-tag: e47354ff-82f5-42c4-b3dc-88dd9c04b770 |
84f19a49 | 345 | ;;; mouse-drag.el ends here |