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092af6d8 RS |
1 | ;;; mouse-drag.el --- use mouse-2 to do a new style of scrolling |
2 | ||
0d30b337 | 3 | ;; Copyright (C) 1996, 1997, 2001, 2002, 2003, 2004, |
409cc4a3 | 4 | ;; 2005, 2006, 2007, 2008 Free Software Foundation, Inc. |
84f19a49 | 5 | |
bc28b212 RS |
6 | ;; Author: John Heidemann <johnh@ISI.EDU> |
7 | ;; Keywords: mouse | |
84f19a49 RS |
8 | |
9 | ;; This file is part of GNU Emacs. | |
10 | ||
eb3fa2cf | 11 | ;; GNU Emacs is free software: you can redistribute it and/or modify |
84f19a49 | 12 | ;; it under the terms of the GNU General Public License as published by |
eb3fa2cf GM |
13 | ;; the Free Software Foundation, either version 3 of the License, or |
14 | ;; (at your option) any later version. | |
84f19a49 RS |
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 | |
eb3fa2cf | 22 | ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. |
84f19a49 RS |
23 | |
24 | ;;; Commentary: | |
25 | ||
ea89d720 SM |
26 | ;; What is ``mouse-drag.el''? |
27 | ;; | |
28 | ;; Doesn't that scroll bar seem far away when you want to scroll? | |
29 | ;; This module overloads mouse-2 to do ``throw'' scrolling. You | |
30 | ;; click and drag. The distance you move from your original click | |
31 | ;; turns into a scroll amount. The scroll amount is scaled | |
32 | ;; exponentially to make both large moves and short adjustments easy. | |
33 | ;; What this boils down to is that you can easily scroll around the | |
34 | ;; buffer without much mouse movement. Finally, clicks which aren't | |
35 | ;; drags are passed off to the old mouse-2 binding, so old mouse-2 | |
36 | ;; operations (find-file in dired-mode, yanking in most other modes) | |
37 | ;; still work. | |
38 | ;; | |
39 | ;; There is an alternative way to scroll, ``drag'' scrolling. You | |
40 | ;; can click on a character and then drag it around, scrolling the | |
41 | ;; buffer with you. The character always stays under the mouse. | |
42 | ;; Compared to throw-scrolling, this approach provides direct | |
43 | ;; manipulation (nice) but requires more mouse movement | |
44 | ;; (unfortunate). It is offered as an alternative for those who | |
45 | ;; prefer it. | |
46 | ;; | |
47 | ;; If you like mouse-drag, you should also check out mouse-copy | |
48 | ;; for ``one-click text copy and move''. | |
49 | ;; | |
50 | ;; To use mouse-drag, place the following in your .emacs file: | |
51 | ;; (require 'mouse-drag) | |
52 | ;; -and either- | |
53 | ;; (global-set-key [down-mouse-2] 'mouse-drag-throw) | |
54 | ;; -or- | |
55 | ;; (global-set-key [down-mouse-2] 'mouse-drag-drag) | |
56 | ;; | |
57 | ;; | |
58 | ;; | |
59 | ;; Options: | |
60 | ;; | |
61 | ;; - reverse the throw-scroll direction with \\[mouse-throw-with-scroll-bar] | |
62 | ;; - work around a bug with \\[mouse-extras-work-around-drag-bug] | |
63 | ;; - auto-enable horizontal scrolling with | |
64 | ;; \\[mouse-drag-electric-col-scrolling] | |
65 | ;; | |
66 | ;; | |
67 | ;; History and related work: | |
68 | ;; | |
69 | ;; One-click copying and moving was inspired by lemacs-19.8. | |
70 | ;; Throw-scrolling was inspired by MacPaint's ``hand'' and by Tk's | |
71 | ;; mouse-2 scrolling. The package mouse-scroll.el by Tom Wurgler | |
72 | ;; <twurgler@goodyear.com> is similar to mouse-drag-throw, but | |
73 | ;; doesn't pass clicks through. | |
74 | ;; | |
75 | ;; These functions have been tested in emacs version 19.30, | |
76 | ;; and this package has run in the past on 19.25-19.29. | |
77 | ;; | |
78 | ;; Originally mouse-drag was part of a larger package. | |
79 | ;; As of 11 July 96 the scrolling functions were split out | |
80 | ;; in preparation for incorporation into (the future) emacs-19.32. | |
81 | ;; | |
ea89d720 SM |
82 | ;; Thanks: |
83 | ;; | |
84 | ;; Thanks to Kai Grossjohann | |
85 | ;; <grossjoh@dusty.informatik.uni-dortmund.de> for reporting bugs, to | |
86 | ;; Tom Wurgler <twurgler@goodyear.com> for reporting bugs and | |
87 | ;; suggesting fixes, and to Joel Graber <jgraber@ti.com> for | |
88 | ;; prompting me to do drag-scrolling and for an initial | |
89 | ;; implementation of horizontal drag-scrolling. | |
90 | ;; | |
91 | ;; -johnh@isi.edu, 11-Jul-96 | |
92 | ;; | |
93 | ;; | |
94 | ;; What's new with mouse-drag 2.24? | |
95 | ;; | |
96 | ;; - mouse-drag-electric-col-scrolling (default: on) | |
97 | ;; auto-enables horizontal scrolling when clicks on wrapped | |
98 | ;; lines occur | |
99 | ||
100 | ;; TODO: | |
101 | ;; - For mouse-drag-throw, we should try and place some visual indicator | |
102 | ;; of the original mouse position (like Firefox does). | |
103 | ||
84f19a49 RS |
104 | ;;; Code: |
105 | ||
106 | ;; | |
107 | ;; scrolling code | |
108 | ;; | |
109 | ||
110 | (defun mouse-drag-safe-scroll (row-delta &optional col-delta) | |
8c398124 | 111 | "Scroll down ROW-DELTA lines and right COL-DELTA, ignoring buffer edge errors. |
84f19a49 | 112 | Keep the cursor on the screen as needed." |
f1ade7d3 GM |
113 | (let ((scroll-preserve-screen-position nil)) |
114 | (if (and row-delta | |
115 | (/= 0 row-delta)) | |
116 | (condition-case nil ;; catch and ignore movement errors | |
117 | (scroll-down row-delta) | |
118 | (beginning-of-buffer (message "Beginning of buffer")) | |
119 | (end-of-buffer (message "End of buffer")))) | |
120 | (if (and col-delta | |
121 | (/= 0 col-delta)) | |
122 | (progn | |
123 | (scroll-right col-delta) | |
124 | ;; Make sure that the point stays on the visible screen | |
125 | ;; (if truncation-lines in set). | |
126 | ;; This code mimics the behavior we automatically get | |
127 | ;; when doing vertical scrolling. | |
128 | ;; Problem identified and a fix suggested by Tom Wurgler. | |
129 | (cond | |
130 | ((< (current-column) (window-hscroll)) | |
131 | (move-to-column (window-hscroll))) ; make on left column | |
132 | ((> (- (current-column) (window-hscroll) (window-width) -2) 0) | |
133 | (move-to-column (+ (window-width) (window-hscroll) -3)))))))) | |
84f19a49 RS |
134 | |
135 | (defun mouse-drag-repeatedly-safe-scroll (row-delta &optional col-delta) | |
8c398124 | 136 | "Scroll ROW-DELTA rows and COL-DELTA cols until an event happens." |
84f19a49 RS |
137 | (while (sit-for mouse-scroll-delay) |
138 | (mouse-drag-safe-scroll row-delta col-delta))) | |
139 | ||
140 | (defun mouse-drag-events-are-point-events-p (start-posn end-posn) | |
8c398124 | 141 | "Determine if START-POSN and END-POSN are \"close\"." |
84f19a49 RS |
142 | (let* |
143 | ((start-col-row (posn-col-row start-posn)) | |
144 | (end-col-row (posn-col-row end-posn))) | |
145 | (and | |
ea89d720 SM |
146 | ;; ;; We no longer exclude things by time. |
147 | ;; (< (- (posn-timestamp end-posn) (posn-timestamp start-posn)) | |
148 | ;; (if (numberp double-click-time) | |
149 | ;; (* 2 double-click-time) ;; stretch it a little | |
150 | ;; 999999)) ;; non-numeric => check by position alone | |
84f19a49 RS |
151 | (= (car start-col-row) (car end-col-row)) |
152 | (= (cdr start-col-row) (cdr end-col-row))))) | |
153 | ||
351d52f7 KH |
154 | (defvar mouse-drag-electric-col-scrolling t |
155 | "If non-nil, mouse-drag on a long line enables truncate-lines.") | |
156 | ||
84f19a49 | 157 | (defun mouse-drag-should-do-col-scrolling () |
8c398124 | 158 | "Determine if it's wise to enable col-scrolling for the current window. |
351d52f7 | 159 | Basically, we check for existing horizontal scrolling." |
84f19a49 RS |
160 | (or truncate-lines |
161 | (> (window-hscroll (selected-window)) 0) | |
70ad3da9 | 162 | (not (window-full-width-p)) |
351d52f7 KH |
163 | (and |
164 | mouse-drag-electric-col-scrolling | |
165 | (save-excursion ;; on a long line? | |
166 | (let | |
167 | ((beg (progn (beginning-of-line) (point))) | |
168 | (end (progn (end-of-line) (point)))) | |
169 | (if (> (- end beg) (window-width)) | |
170 | (setq truncate-lines t) | |
171 | nil)))))) | |
84f19a49 RS |
172 | |
173 | (defvar mouse-throw-with-scroll-bar nil | |
8c398124 | 174 | "*Set direction of mouse-throwing. |
84f19a49 RS |
175 | If nil, the text moves in the direction the mouse moves. |
176 | If t, the scroll bar moves in the direction the mouse moves.") | |
84f19a49 RS |
177 | (defconst mouse-throw-magnifier-min -6) |
178 | (defconst mouse-throw-magnifier-max 6) | |
ea89d720 SM |
179 | (defconst mouse-throw-magnifier-base 1.5) |
180 | ||
181 | (defun mouse-drag-scroll-delta (mouse-delta) | |
182 | ;; Limit the exponential explosion. | |
183 | (setq mouse-delta | |
184 | (max mouse-throw-magnifier-min | |
185 | (min mouse-throw-magnifier-max mouse-delta))) | |
186 | (* (round (exp (* (log mouse-throw-magnifier-base) (abs mouse-delta)))) | |
187 | (if (< mouse-delta 0) -1 1) | |
188 | (if mouse-throw-with-scroll-bar 1 -1))) | |
189 | ||
84f19a49 RS |
190 | |
191 | (defun mouse-drag-throw (start-event) | |
192 | "\"Throw\" the page according to a mouse drag. | |
193 | ||
194 | A \"throw\" is scrolling the page at a speed relative to the distance | |
195 | from the original mouse click to the current mouse location. Try it; | |
196 | you'll like it. It's easier to observe than to explain. | |
197 | ||
198 | If the mouse is clicked and released in the same place of time we | |
199 | assume that the user didn't want to scdebugroll but wanted to whatever | |
200 | mouse-2 used to do, so we pass it through. | |
201 | ||
202 | Throw scrolling was inspired (but is not identical to) the \"hand\" | |
203 | option in MacPaint, or the middle button in Tk text widgets. | |
204 | ||
205 | If `mouse-throw-with-scroll-bar' is non-nil, then this command scrolls | |
206 | in the opposite direction. (Different people have different ideas | |
207 | about which direction is natural. Perhaps it has to do with which | |
208 | hemisphere you're in.) | |
209 | ||
210 | To test this function, evaluate: | |
211 | (global-set-key [down-mouse-2] 'mouse-drag-throw)" | |
212 | (interactive "e") | |
213 | ;; we want to do save-selected-window, but that requires 19.29 | |
214 | (let* ((start-posn (event-start start-event)) | |
215 | (start-window (posn-window start-posn)) | |
216 | (start-row (cdr (posn-col-row start-posn))) | |
217 | (start-col (car (posn-col-row start-posn))) | |
218 | (old-selected-window (selected-window)) | |
219 | event end row mouse-delta scroll-delta | |
e35afc97 | 220 | have-scrolled |
84f19a49 RS |
221 | window-last-row |
222 | col mouse-col-delta window-last-col | |
223 | (scroll-col-delta 0) | |
224 | adjusted-mouse-col-delta | |
4ebeb09d | 225 | adjusted-mouse-delta |
84f19a49 RS |
226 | ;; be conservative about allowing horizontal scrolling |
227 | (col-scrolling-p (mouse-drag-should-do-col-scrolling))) | |
228 | (select-window start-window) | |
229 | (track-mouse | |
230 | (while (progn | |
231 | (setq event (read-event) | |
232 | end (event-end event) | |
233 | row (cdr (posn-col-row end)) | |
234 | col (car (posn-col-row end))) | |
235 | (or (mouse-movement-p event) | |
236 | (eq (car-safe event) 'switch-frame))) | |
ea89d720 SM |
237 | (when (eq start-window (posn-window end)) |
238 | (when col-scrolling-p | |
239 | (setq scroll-col-delta (mouse-drag-scroll-delta (- start-col col)))) | |
240 | (setq scroll-delta (mouse-drag-scroll-delta (- start-row row)))) | |
241 | ||
84f19a49 RS |
242 | (if (or (/= 0 scroll-delta) |
243 | (/= 0 scroll-col-delta)) | |
244 | (progn | |
245 | (setq have-scrolled t) | |
246 | (mouse-drag-safe-scroll scroll-delta scroll-col-delta) | |
247 | (mouse-drag-repeatedly-safe-scroll scroll-delta scroll-col-delta))))) ;xxx | |
248 | ;; If it was a click and not a drag, prepare to pass the event on. | |
e35afc97 | 249 | ;; Is there a more correct way to reconstruct the event? |
84f19a49 RS |
250 | (if (and (not have-scrolled) |
251 | (mouse-drag-events-are-point-events-p start-posn end)) | |
e35afc97 RS |
252 | (push (cons (event-basic-type start-event) (cdr start-event)) |
253 | unread-command-events)) | |
84f19a49 | 254 | ;; Now restore the old window. |
e35afc97 | 255 | (select-window old-selected-window))) |
84f19a49 RS |
256 | |
257 | (defun mouse-drag-drag (start-event) | |
258 | "\"Drag\" the page according to a mouse drag. | |
259 | ||
260 | Drag scrolling moves the page according to the movement of the mouse. | |
261 | You \"grab\" the character under the mouse and move it around. | |
262 | ||
263 | If the mouse is clicked and released in the same place of time we | |
264 | assume that the user didn't want to scroll but wanted to whatever | |
265 | mouse-2 used to do, so we pass it through. | |
266 | ||
267 | Drag scrolling is identical to the \"hand\" option in MacPaint, or the | |
268 | middle button in Tk text widgets. | |
269 | ||
270 | To test this function, evaluate: | |
271 | (global-set-key [down-mouse-2] 'mouse-drag-drag)" | |
272 | (interactive "e") | |
273 | ;; we want to do save-selected-window, but that requires 19.29 | |
274 | (let* ((start-posn (event-start start-event)) | |
275 | (start-window (posn-window start-posn)) | |
276 | (start-row (cdr (posn-col-row start-posn))) | |
277 | (start-col (car (posn-col-row start-posn))) | |
278 | (old-selected-window (selected-window)) | |
279 | event end row mouse-delta scroll-delta | |
e35afc97 | 280 | have-scrolled |
84f19a49 RS |
281 | window-last-row |
282 | col mouse-col-delta window-last-col | |
283 | (scroll-col-delta 0) | |
284 | ;; be conservative about allowing horizontal scrolling | |
285 | (col-scrolling-p (mouse-drag-should-do-col-scrolling))) | |
286 | (select-window start-window) | |
287 | (setq window-last-row (- (window-height) 2) | |
288 | window-last-col (- (window-width) 2)) | |
289 | (track-mouse | |
290 | (while (progn | |
291 | (setq event (read-event) | |
292 | end (event-end event) | |
293 | row (cdr (posn-col-row end)) | |
294 | col (car (posn-col-row end))) | |
295 | (or (mouse-movement-p event) | |
296 | (eq (car-safe event) 'switch-frame))) | |
297 | ;; Scroll if see if we're on the edge. | |
298 | ;; NEEDSWORK: should handle mouse-in-other window. | |
299 | (cond | |
300 | ((not (eq start-window (posn-window end))) | |
301 | t) ; wait for return to original window | |
302 | ((<= row 0) (mouse-drag-repeatedly-safe-scroll -1 0)) | |
303 | ((>= row window-last-row) (mouse-drag-repeatedly-safe-scroll 1 0)) | |
304 | ((and col-scrolling-p (<= col 1)) (mouse-drag-repeatedly-safe-scroll 0 -1)) | |
305 | ((and col-scrolling-p (>= col window-last-col)) (mouse-drag-repeatedly-safe-scroll 0 1)) | |
306 | (t | |
307 | (setq scroll-delta (- row start-row) | |
308 | start-row row) | |
309 | (if col-scrolling-p | |
310 | (setq scroll-col-delta (- col start-col) | |
311 | start-col col)) | |
312 | (if (or (/= 0 scroll-delta) | |
313 | (/= 0 scroll-col-delta)) | |
314 | (progn | |
315 | (setq have-scrolled t) | |
316 | (mouse-drag-safe-scroll scroll-delta scroll-col-delta))))))) | |
317 | ;; If it was a click and not a drag, prepare to pass the event on. | |
e35afc97 | 318 | ;; Is there a more correct way to reconstruct the event? |
84f19a49 RS |
319 | (if (and (not have-scrolled) |
320 | (mouse-drag-events-are-point-events-p start-posn end)) | |
e35afc97 RS |
321 | (push (cons (event-basic-type start-event) (cdr start-event)) |
322 | unread-command-events)) | |
84f19a49 | 323 | ;; Now restore the old window. |
e35afc97 RS |
324 | (select-window old-selected-window))) |
325 | ||
84f19a49 RS |
326 | |
327 | (provide 'mouse-drag) | |
328 | ||
cbee283d | 329 | ;; arch-tag: e47354ff-82f5-42c4-b3dc-88dd9c04b770 |
84f19a49 | 330 | ;;; mouse-drag.el ends here |