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092af6d8 RS |
1 | ;;; mouse-drag.el --- use mouse-2 to do a new style of scrolling |
2 | ||
ab422c4d | 3 | ;; Copyright (C) 1996-1997, 2001-2013 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 | ||
eb3fa2cf | 10 | ;; GNU Emacs is free software: you can redistribute it and/or modify |
84f19a49 | 11 | ;; it under the terms of the GNU General Public License as published by |
eb3fa2cf GM |
12 | ;; the Free Software Foundation, either version 3 of the License, or |
13 | ;; (at your option) any later version. | |
84f19a49 RS |
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 | |
eb3fa2cf | 21 | ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. |
84f19a49 RS |
22 | |
23 | ;;; Commentary: | |
24 | ||
ea89d720 SM |
25 | ;; What is ``mouse-drag.el''? |
26 | ;; | |
27 | ;; Doesn't that scroll bar seem far away when you want to scroll? | |
28 | ;; This module overloads mouse-2 to do ``throw'' scrolling. You | |
29 | ;; click and drag. The distance you move from your original click | |
30 | ;; turns into a scroll amount. The scroll amount is scaled | |
31 | ;; exponentially to make both large moves and short adjustments easy. | |
32 | ;; What this boils down to is that you can easily scroll around the | |
33 | ;; buffer without much mouse movement. Finally, clicks which aren't | |
34 | ;; drags are passed off to the old mouse-2 binding, so old mouse-2 | |
35 | ;; operations (find-file in dired-mode, yanking in most other modes) | |
36 | ;; still work. | |
37 | ;; | |
38 | ;; There is an alternative way to scroll, ``drag'' scrolling. You | |
39 | ;; can click on a character and then drag it around, scrolling the | |
40 | ;; buffer with you. The character always stays under the mouse. | |
41 | ;; Compared to throw-scrolling, this approach provides direct | |
42 | ;; manipulation (nice) but requires more mouse movement | |
43 | ;; (unfortunate). It is offered as an alternative for those who | |
44 | ;; prefer it. | |
45 | ;; | |
46 | ;; If you like mouse-drag, you should also check out mouse-copy | |
47 | ;; for ``one-click text copy and move''. | |
48 | ;; | |
865fe16f | 49 | ;; To use mouse-drag, place the following in your init file: |
1bd38124 | 50 | ;; -either- |
ea89d720 SM |
51 | ;; (global-set-key [down-mouse-2] 'mouse-drag-throw) |
52 | ;; -or- | |
53 | ;; (global-set-key [down-mouse-2] 'mouse-drag-drag) | |
54 | ;; | |
55 | ;; | |
56 | ;; | |
57 | ;; Options: | |
58 | ;; | |
59 | ;; - reverse the throw-scroll direction with \\[mouse-throw-with-scroll-bar] | |
60 | ;; - work around a bug with \\[mouse-extras-work-around-drag-bug] | |
61 | ;; - auto-enable horizontal scrolling with | |
62 | ;; \\[mouse-drag-electric-col-scrolling] | |
63 | ;; | |
64 | ;; | |
65 | ;; History and related work: | |
66 | ;; | |
67 | ;; One-click copying and moving was inspired by lemacs-19.8. | |
68 | ;; Throw-scrolling was inspired by MacPaint's ``hand'' and by Tk's | |
69 | ;; mouse-2 scrolling. The package mouse-scroll.el by Tom Wurgler | |
70 | ;; <twurgler@goodyear.com> is similar to mouse-drag-throw, but | |
71 | ;; doesn't pass clicks through. | |
72 | ;; | |
73 | ;; These functions have been tested in emacs version 19.30, | |
74 | ;; and this package has run in the past on 19.25-19.29. | |
75 | ;; | |
76 | ;; Originally mouse-drag was part of a larger package. | |
77 | ;; As of 11 July 96 the scrolling functions were split out | |
78 | ;; in preparation for incorporation into (the future) emacs-19.32. | |
79 | ;; | |
ea89d720 SM |
80 | ;; Thanks: |
81 | ;; | |
82 | ;; Thanks to Kai Grossjohann | |
83 | ;; <grossjoh@dusty.informatik.uni-dortmund.de> for reporting bugs, to | |
84 | ;; Tom Wurgler <twurgler@goodyear.com> for reporting bugs and | |
85 | ;; suggesting fixes, and to Joel Graber <jgraber@ti.com> for | |
86 | ;; prompting me to do drag-scrolling and for an initial | |
87 | ;; implementation of horizontal drag-scrolling. | |
88 | ;; | |
89 | ;; -johnh@isi.edu, 11-Jul-96 | |
90 | ;; | |
91 | ;; | |
92 | ;; What's new with mouse-drag 2.24? | |
93 | ;; | |
94 | ;; - mouse-drag-electric-col-scrolling (default: on) | |
95 | ;; auto-enables horizontal scrolling when clicks on wrapped | |
96 | ;; lines occur | |
97 | ||
98 | ;; TODO: | |
99 | ;; - For mouse-drag-throw, we should try and place some visual indicator | |
100 | ;; of the original mouse position (like Firefox does). | |
101 | ||
84f19a49 RS |
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 | |
ea89d720 SM |
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 | |
84f19a49 RS |
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) | |
70ad3da9 | 160 | (not (window-full-width-p)) |
351d52f7 KH |
161 | (and |
162 | mouse-drag-electric-col-scrolling | |
163 | (save-excursion ;; on a long line? | |
164 | (let | |
9b026d9f | 165 | ((beg (line-beginning-position)) |
351d52f7 KH |
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 | |
fb7ada5f | 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.") | |
84f19a49 RS |
175 | (defconst mouse-throw-magnifier-min -6) |
176 | (defconst mouse-throw-magnifier-max 6) | |
ea89d720 SM |
177 | (defconst mouse-throw-magnifier-base 1.5) |
178 | ||
179 | (defun mouse-drag-scroll-delta (mouse-delta) | |
180 | ;; Limit the exponential explosion. | |
181 | (setq mouse-delta | |
182 | (max mouse-throw-magnifier-min | |
183 | (min mouse-throw-magnifier-max mouse-delta))) | |
184 | (* (round (exp (* (log mouse-throw-magnifier-base) (abs mouse-delta)))) | |
185 | (if (< mouse-delta 0) -1 1) | |
186 | (if mouse-throw-with-scroll-bar 1 -1))) | |
187 | ||
1bd38124 | 188 | ;;;###autoload |
84f19a49 RS |
189 | (defun mouse-drag-throw (start-event) |
190 | "\"Throw\" the page according to a mouse drag. | |
191 | ||
192 | A \"throw\" is scrolling the page at a speed relative to the distance | |
193 | from the original mouse click to the current mouse location. Try it; | |
194 | you'll like it. It's easier to observe than to explain. | |
195 | ||
196 | If the mouse is clicked and released in the same place of time we | |
6470c3c6 | 197 | assume that the user didn't want to scroll but wanted to whatever |
84f19a49 RS |
198 | mouse-2 used to do, so we pass it through. |
199 | ||
200 | Throw scrolling was inspired (but is not identical to) the \"hand\" | |
201 | option in MacPaint, or the middle button in Tk text widgets. | |
202 | ||
203 | If `mouse-throw-with-scroll-bar' is non-nil, then this command scrolls | |
204 | in the opposite direction. (Different people have different ideas | |
205 | about which direction is natural. Perhaps it has to do with which | |
206 | hemisphere you're in.) | |
207 | ||
208 | To test this function, evaluate: | |
209 | (global-set-key [down-mouse-2] 'mouse-drag-throw)" | |
210 | (interactive "e") | |
211 | ;; we want to do save-selected-window, but that requires 19.29 | |
212 | (let* ((start-posn (event-start start-event)) | |
213 | (start-window (posn-window start-posn)) | |
214 | (start-row (cdr (posn-col-row start-posn))) | |
215 | (start-col (car (posn-col-row start-posn))) | |
216 | (old-selected-window (selected-window)) | |
06b60517 | 217 | event end row scroll-delta |
e35afc97 | 218 | have-scrolled |
06b60517 | 219 | col |
84f19a49 | 220 | (scroll-col-delta 0) |
84f19a49 RS |
221 | ;; be conservative about allowing horizontal scrolling |
222 | (col-scrolling-p (mouse-drag-should-do-col-scrolling))) | |
223 | (select-window start-window) | |
224 | (track-mouse | |
225 | (while (progn | |
226 | (setq event (read-event) | |
227 | end (event-end event) | |
228 | row (cdr (posn-col-row end)) | |
229 | col (car (posn-col-row end))) | |
230 | (or (mouse-movement-p event) | |
231 | (eq (car-safe event) 'switch-frame))) | |
ea89d720 SM |
232 | (when (eq start-window (posn-window end)) |
233 | (when col-scrolling-p | |
234 | (setq scroll-col-delta (mouse-drag-scroll-delta (- start-col col)))) | |
235 | (setq scroll-delta (mouse-drag-scroll-delta (- start-row row)))) | |
236 | ||
84f19a49 RS |
237 | (if (or (/= 0 scroll-delta) |
238 | (/= 0 scroll-col-delta)) | |
239 | (progn | |
240 | (setq have-scrolled t) | |
241 | (mouse-drag-safe-scroll scroll-delta scroll-col-delta) | |
242 | (mouse-drag-repeatedly-safe-scroll scroll-delta scroll-col-delta))))) ;xxx | |
243 | ;; If it was a click and not a drag, prepare to pass the event on. | |
e35afc97 | 244 | ;; Is there a more correct way to reconstruct the event? |
84f19a49 RS |
245 | (if (and (not have-scrolled) |
246 | (mouse-drag-events-are-point-events-p start-posn end)) | |
e35afc97 RS |
247 | (push (cons (event-basic-type start-event) (cdr start-event)) |
248 | unread-command-events)) | |
84f19a49 | 249 | ;; Now restore the old window. |
e35afc97 | 250 | (select-window old-selected-window))) |
84f19a49 | 251 | |
1bd38124 | 252 | ;;;###autoload |
84f19a49 RS |
253 | (defun mouse-drag-drag (start-event) |
254 | "\"Drag\" the page according to a mouse drag. | |
255 | ||
256 | Drag scrolling moves the page according to the movement of the mouse. | |
257 | You \"grab\" the character under the mouse and move it around. | |
258 | ||
259 | If the mouse is clicked and released in the same place of time we | |
260 | assume that the user didn't want to scroll but wanted to whatever | |
261 | mouse-2 used to do, so we pass it through. | |
262 | ||
263 | Drag scrolling is identical to the \"hand\" option in MacPaint, or the | |
264 | middle button in Tk text widgets. | |
265 | ||
266 | To test this function, evaluate: | |
267 | (global-set-key [down-mouse-2] 'mouse-drag-drag)" | |
268 | (interactive "e") | |
269 | ;; we want to do save-selected-window, but that requires 19.29 | |
270 | (let* ((start-posn (event-start start-event)) | |
271 | (start-window (posn-window start-posn)) | |
272 | (start-row (cdr (posn-col-row start-posn))) | |
273 | (start-col (car (posn-col-row start-posn))) | |
274 | (old-selected-window (selected-window)) | |
06b60517 | 275 | event end row scroll-delta |
e35afc97 | 276 | have-scrolled |
84f19a49 | 277 | window-last-row |
06b60517 | 278 | col window-last-col |
84f19a49 RS |
279 | (scroll-col-delta 0) |
280 | ;; be conservative about allowing horizontal scrolling | |
281 | (col-scrolling-p (mouse-drag-should-do-col-scrolling))) | |
282 | (select-window start-window) | |
283 | (setq window-last-row (- (window-height) 2) | |
284 | window-last-col (- (window-width) 2)) | |
285 | (track-mouse | |
286 | (while (progn | |
287 | (setq event (read-event) | |
288 | end (event-end event) | |
289 | row (cdr (posn-col-row end)) | |
290 | col (car (posn-col-row end))) | |
291 | (or (mouse-movement-p event) | |
292 | (eq (car-safe event) 'switch-frame))) | |
293 | ;; Scroll if see if we're on the edge. | |
294 | ;; NEEDSWORK: should handle mouse-in-other window. | |
295 | (cond | |
296 | ((not (eq start-window (posn-window end))) | |
297 | t) ; wait for return to original window | |
298 | ((<= row 0) (mouse-drag-repeatedly-safe-scroll -1 0)) | |
299 | ((>= row window-last-row) (mouse-drag-repeatedly-safe-scroll 1 0)) | |
300 | ((and col-scrolling-p (<= col 1)) (mouse-drag-repeatedly-safe-scroll 0 -1)) | |
301 | ((and col-scrolling-p (>= col window-last-col)) (mouse-drag-repeatedly-safe-scroll 0 1)) | |
302 | (t | |
303 | (setq scroll-delta (- row start-row) | |
304 | start-row row) | |
305 | (if col-scrolling-p | |
306 | (setq scroll-col-delta (- col start-col) | |
307 | start-col col)) | |
308 | (if (or (/= 0 scroll-delta) | |
309 | (/= 0 scroll-col-delta)) | |
310 | (progn | |
311 | (setq have-scrolled t) | |
312 | (mouse-drag-safe-scroll scroll-delta scroll-col-delta))))))) | |
313 | ;; If it was a click and not a drag, prepare to pass the event on. | |
e35afc97 | 314 | ;; Is there a more correct way to reconstruct the event? |
84f19a49 RS |
315 | (if (and (not have-scrolled) |
316 | (mouse-drag-events-are-point-events-p start-posn end)) | |
e35afc97 RS |
317 | (push (cons (event-basic-type start-event) (cdr start-event)) |
318 | unread-command-events)) | |
84f19a49 | 319 | ;; Now restore the old window. |
e35afc97 RS |
320 | (select-window old-selected-window))) |
321 | ||
84f19a49 RS |
322 | |
323 | (provide 'mouse-drag) | |
324 | ||
325 | ;;; mouse-drag.el ends here |