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55535639 | 1 | ;;; scroll-bar.el --- window system-independent scroll bar support |
6d62a90e | 2 | |
64453f32 | 3 | ;; Copyright (C) 1993, 1994, 1995, 1999, 2000, 2001, 2003 |
d08947c5 | 4 | ;; Free Software Foundation, Inc. |
6d62a90e JB |
5 | |
6 | ;; Maintainer: FSF | |
7 | ;; Keywords: hardware | |
8 | ||
b578f267 | 9 | ;; This file is part of GNU Emacs. |
6d62a90e | 10 | |
b578f267 EN |
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. | |
6d62a90e | 15 | |
b578f267 EN |
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. | |
6d62a90e | 20 | |
b578f267 EN |
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., 59 Temple Place - Suite 330, | |
24 | ;; Boston, MA 02111-1307, USA. | |
76550a57 | 25 | |
d9ecc911 ER |
26 | ;;; Commentary: |
27 | ||
28 | ;; Window-system-independent bindings of mouse clicks on the scroll bar. | |
29 | ;; Presently emulates the scroll-bar behavior of xterm. | |
b578f267 | 30 | |
d9ecc911 ER |
31 | ;;; Code: |
32 | ||
dbc4e1c1 JB |
33 | (require 'mouse) |
34 | ||
6d62a90e JB |
35 | \f |
36 | ;;;; Utilities. | |
37 | ||
86828678 RS |
38 | (defun scroll-bar-event-ratio (event) |
39 | "Given a scroll bar event EVENT, return the scroll bar position as a ratio. | |
40 | The value is a cons cell (PORTION . WHOLE) containing two integers | |
41 | whose ratio gives the event's vertical position in the scroll bar, with 0 | |
42 | referring to the top and 1 to the bottom." | |
43 | (nth 2 event)) | |
44 | ||
bf3c8a70 | 45 | (defun scroll-bar-scale (num-denom whole) |
6d62a90e | 46 | "Given a pair (NUM . DENOM) and WHOLE, return (/ (* NUM WHOLE) DENOM). |
bf3c8a70 JB |
47 | This is handy for scaling a position on a scroll bar into real units, |
48 | like buffer positions. If SCROLL-BAR-POS is the (PORTION . WHOLE) pair | |
49 | from a scroll bar event, then (scroll-bar-scale SCROLL-BAR-POS | |
6d62a90e | 50 | \(buffer-size)) is the position in the current buffer corresponding to |
bf3c8a70 | 51 | that scroll bar position." |
6d62a90e JB |
52 | ;; We multiply before we divide to maintain precision. |
53 | ;; We use floating point because the product of a large buffer size | |
bf3c8a70 | 54 | ;; with a large scroll bar portion can easily overflow a lisp int. |
6d62a90e JB |
55 | (truncate (/ (* (float (car num-denom)) whole) (cdr num-denom)))) |
56 | ||
57 | \f | |
fe48f821 | 58 | ;;;; Helpful functions for enabling and disabling scroll bars. |
fe48f821 | 59 | |
1064fe38 RS |
60 | (defvar scroll-bar-mode) |
61 | ||
2124851f RS |
62 | (defvar scroll-bar-mode-explicit nil |
63 | "Non-nil means `set-scroll-bar-mode' should really do something. | |
64 | This is nil while loading `scroll-bar.el', and t afterward.") | |
65 | ||
e4b201bb KH |
66 | (defun set-scroll-bar-mode-1 (ignore value) |
67 | (set-scroll-bar-mode value)) | |
68 | ||
69 | (defun set-scroll-bar-mode (value) | |
04c34f2e RS |
70 | "Set `scroll-bar-mode' to VALUE and put the new value into effect." |
71 | (setq scroll-bar-mode value) | |
72 | ||
2124851f RS |
73 | (when scroll-bar-mode-explicit |
74 | ;; Apply it to default-frame-alist. | |
75 | (let ((parameter (assq 'vertical-scroll-bars default-frame-alist))) | |
76 | (if (consp parameter) | |
77 | (setcdr parameter scroll-bar-mode) | |
78 | (setq default-frame-alist | |
79 | (cons (cons 'vertical-scroll-bars scroll-bar-mode) | |
80 | default-frame-alist)))) | |
81 | ||
82 | ;; Apply it to existing frames. | |
83 | (let ((frames (frame-list))) | |
84 | (while frames | |
85 | (modify-frame-parameters | |
86 | (car frames) | |
87 | (list (cons 'vertical-scroll-bars scroll-bar-mode))) | |
88 | (setq frames (cdr frames)))))) | |
04c34f2e | 89 | |
1032e793 | 90 | (defcustom scroll-bar-mode |
ded8a542 | 91 | (cond ((eq system-type 'windows-nt) 'right) |
7413b888 | 92 | ((featurep 'mac-carbon) 'right) |
ded8a542 | 93 | (t 'left)) |
04c34f2e RS |
94 | "*Specify whether to have vertical scroll bars, and on which side. |
95 | Possible values are nil (no scroll bars), `left' (scroll bars on left) | |
96 | and `right' (scroll bars on right). | |
463deb66 RS |
97 | To set this variable in a Lisp program, use `set-scroll-bar-mode' |
98 | to make it take real effect. | |
99 | Setting the variable with a customization buffer also takes effect." | |
64453f32 | 100 | :type '(choice (const :tag "none (nil)" nil) |
04c34f2e RS |
101 | (const left) |
102 | (const right)) | |
103 | :group 'frames | |
2669fbfb RS |
104 | ;; The default value for :initialize would try to use :set |
105 | ;; when processing the file in cus-dep.el. | |
106 | :initialize 'custom-initialize-default | |
e4b201bb | 107 | :set 'set-scroll-bar-mode-1) |
04c34f2e | 108 | |
2124851f RS |
109 | ;; We just set scroll-bar-mode, but that was the default. |
110 | ;; If it is set again, that is for real. | |
111 | (setq scroll-bar-mode-explicit t) | |
112 | ||
b1ad7c13 | 113 | (defun scroll-bar-mode (&optional flag) |
04c34f2e | 114 | "Toggle display of vertical scroll bars on all frames. |
fe48f821 JB |
115 | This command applies to all frames that exist and frames to be |
116 | created in the future. | |
117 | With a numeric argument, if the argument is negative, | |
118 | turn off scroll bars; otherwise, turn on scroll bars." | |
119 | (interactive "P") | |
6ee9f953 | 120 | (if flag (setq flag (prefix-numeric-value flag))) |
ada464a7 | 121 | |
04c34f2e | 122 | ;; Tweedle the variable according to the argument. |
e4b201bb | 123 | (set-scroll-bar-mode (if (null flag) (not scroll-bar-mode) |
04c34f2e | 124 | (and (or (not (numberp flag)) (>= flag 0)) |
ded8a542 | 125 | (cond ((eq system-type 'windows-nt) 'right) |
7413b888 | 126 | ((featurep 'mac-carbon) 'right) |
ded8a542 | 127 | (t 'left)))))) |
04c34f2e RS |
128 | |
129 | (defun toggle-scroll-bar (arg) | |
130 | "Toggle whether or not the selected frame has vertical scroll bars. | |
131 | With arg, turn vertical scroll bars on if and only if arg is positive. | |
132 | The variable `scroll-bar-mode' controls which side the scroll bars are on | |
133 | when they are turned on; if it is nil, they go on the left." | |
134 | (interactive "P") | |
135 | (if (null arg) | |
136 | (setq arg | |
137 | (if (cdr (assq 'vertical-scroll-bars | |
138 | (frame-parameters (selected-frame)))) | |
19c6feac KH |
139 | -1 1)) |
140 | (setq arg (prefix-numeric-value arg))) | |
1032e793 GV |
141 | (modify-frame-parameters |
142 | (selected-frame) | |
143 | (list (cons 'vertical-scroll-bars | |
144 | (if (> arg 0) | |
145 | (or scroll-bar-mode | |
ded8a542 | 146 | (cond ((eq system-type 'windows-nt) 'right) |
7413b888 | 147 | ((featurep 'mac-carbon) 'right) |
ded8a542 | 148 | (t 'left)))))))) |
04c34f2e RS |
149 | |
150 | (defun toggle-horizontal-scroll-bar (arg) | |
151 | "Toggle whether or not the selected frame has horizontal scroll bars. | |
152 | With arg, turn horizontal scroll bars on if and only if arg is positive. | |
153 | Horizontal scroll bars aren't implemented yet." | |
154 | (interactive "P") | |
155 | (error "Horizontal scroll bars aren't implemented yet")) | |
fe48f821 | 156 | \f |
bf3c8a70 | 157 | ;;;; Buffer navigation using the scroll bar. |
6d62a90e | 158 | |
e532b016 | 159 | ;;; This was used for up-events on button 2, but no longer. |
bf3c8a70 JB |
160 | (defun scroll-bar-set-window-start (event) |
161 | "Set the window start according to where the scroll bar is dragged. | |
162 | EVENT should be a scroll bar click or drag event." | |
6d62a90e | 163 | (interactive "e") |
dbc4e1c1 | 164 | (let* ((end-position (event-end event)) |
6d62a90e JB |
165 | (window (nth 0 end-position)) |
166 | (portion-whole (nth 2 end-position))) | |
167 | (save-excursion | |
168 | (set-buffer (window-buffer window)) | |
169 | (save-excursion | |
4cad38d5 JB |
170 | (goto-char (+ (point-min) |
171 | (scroll-bar-scale portion-whole | |
172 | (- (point-max) (point-min))))) | |
6d62a90e JB |
173 | (beginning-of-line) |
174 | (set-window-start window (point)))))) | |
175 | ||
aeee66be RS |
176 | (defun scroll-bar-drag-position (portion-whole) |
177 | "Calculate new window start for drag event." | |
178 | (save-excursion | |
179 | (goto-char (+ (point-min) | |
180 | (scroll-bar-scale portion-whole | |
181 | (- (point-max) (point-min))))) | |
182 | (beginning-of-line) | |
183 | (point))) | |
184 | ||
185 | (defun scroll-bar-maybe-set-window-start (event) | |
186 | "Set the window start according to where the scroll bar is dragged. | |
187 | Only change window start if the new start is substantially different. | |
188 | EVENT should be a scroll bar click or drag event." | |
189 | (interactive "e") | |
190 | (let* ((end-position (event-end event)) | |
191 | (window (nth 0 end-position)) | |
192 | (portion-whole (nth 2 end-position)) | |
193 | (next-portion-whole (cons (1+ (car portion-whole)) | |
194 | (cdr portion-whole))) | |
195 | portion-start | |
196 | next-portion-start | |
197 | (current-start (window-start window))) | |
198 | (save-excursion | |
199 | (set-buffer (window-buffer window)) | |
200 | (setq portion-start (scroll-bar-drag-position portion-whole)) | |
201 | (setq next-portion-start (max | |
202 | (scroll-bar-drag-position next-portion-whole) | |
203 | (1+ portion-start))) | |
15655694 | 204 | (if (or (>= current-start next-portion-start) |
aeee66be | 205 | (< current-start portion-start)) |
9c005c65 KH |
206 | (set-window-start window portion-start) |
207 | ;; Always set window start, to ensure scroll bar position is updated. | |
208 | (set-window-start window current-start))))) | |
aeee66be | 209 | |
e532b016 RS |
210 | ;; Scroll the window to the proper position for EVENT. |
211 | (defun scroll-bar-drag-1 (event) | |
212 | (let* ((start-position (event-start event)) | |
213 | (window (nth 0 start-position)) | |
214 | (portion-whole (nth 2 start-position))) | |
215 | (save-excursion | |
216 | (set-buffer (window-buffer window)) | |
d2ae6f7e RS |
217 | ;; Calculate position relative to the accessible part of the buffer. |
218 | (goto-char (+ (point-min) | |
219 | (scroll-bar-scale portion-whole | |
220 | (- (point-max) (point-min))))) | |
9d7ab3f0 | 221 | (vertical-motion 0 window) |
e532b016 RS |
222 | (set-window-start window (point))))) |
223 | ||
224 | (defun scroll-bar-drag (event) | |
225 | "Scroll the window by dragging the scroll bar slider. | |
226 | If you click outside the slider, the window scrolls to bring the slider there." | |
227 | (interactive "e") | |
c782bea5 | 228 | (let* (done |
cb183ca0 RS |
229 | (echo-keystrokes 0) |
230 | (end-position (event-end event)) | |
231 | (window (nth 0 end-position)) | |
232 | (before-scroll)) | |
233 | (with-current-buffer (window-buffer window) | |
234 | (setq before-scroll point-before-scroll)) | |
235 | (save-selected-window | |
236 | (select-window window) | |
237 | (setq before-scroll | |
238 | (or before-scroll (point)))) | |
239 | (scroll-bar-drag-1 event) | |
240 | (track-mouse | |
241 | (while (not done) | |
242 | (setq event (read-event)) | |
243 | (if (eq (car-safe event) 'mouse-movement) | |
244 | (setq event (read-event))) | |
245 | (cond ((eq (car-safe event) 'scroll-bar-movement) | |
246 | (scroll-bar-drag-1 event)) | |
247 | (t | |
248 | ;; Exit when we get the drag event; ignore that event. | |
249 | (setq done t))))) | |
250 | (sit-for 0) | |
251 | (with-current-buffer (window-buffer window) | |
252 | (setq point-before-scroll before-scroll)))) | |
e532b016 | 253 | |
bf3c8a70 JB |
254 | (defun scroll-bar-scroll-down (event) |
255 | "Scroll the window's top line down to the location of the scroll bar click. | |
256 | EVENT should be a scroll bar click." | |
6d62a90e | 257 | (interactive "e") |
cb183ca0 RS |
258 | (let* ((end-position (event-end event)) |
259 | (window (nth 0 end-position)) | |
260 | (before-scroll)) | |
261 | (with-current-buffer (window-buffer window) | |
262 | (setq before-scroll point-before-scroll)) | |
def7db1d KH |
263 | (unwind-protect |
264 | (save-selected-window | |
265 | (let ((portion-whole (nth 2 end-position))) | |
266 | (select-window window) | |
267 | (setq before-scroll | |
268 | (or before-scroll (point))) | |
269 | (scroll-down | |
270 | (scroll-bar-scale portion-whole (1- (window-height))))) | |
271 | (sit-for 0)) | |
272 | (with-current-buffer (window-buffer window) | |
273 | (setq point-before-scroll before-scroll))))) | |
6d62a90e | 274 | |
bf3c8a70 JB |
275 | (defun scroll-bar-scroll-up (event) |
276 | "Scroll the line next to the scroll bar click to the top of the window. | |
277 | EVENT should be a scroll bar click." | |
6d62a90e | 278 | (interactive "e") |
cb183ca0 RS |
279 | (let* ((end-position (event-end event)) |
280 | (window (nth 0 end-position)) | |
281 | (before-scroll)) | |
282 | (with-current-buffer (window-buffer window) | |
283 | (setq before-scroll point-before-scroll)) | |
def7db1d KH |
284 | (unwind-protect |
285 | (save-selected-window | |
286 | (let ((portion-whole (nth 2 end-position))) | |
287 | (select-window window) | |
288 | (setq before-scroll | |
289 | (or before-scroll (point))) | |
290 | (scroll-up | |
291 | (scroll-bar-scale portion-whole (1- (window-height))))) | |
292 | (sit-for 0)) | |
293 | (with-current-buffer (window-buffer window) | |
294 | (setq point-before-scroll before-scroll))))) | |
6d62a90e JB |
295 | |
296 | \f | |
cf4eb316 | 297 | ;;; Tookit scroll bars. |
6d62a90e | 298 | |
cf4eb316 GM |
299 | (defun scroll-bar-toolkit-scroll (event) |
300 | (interactive "e") | |
301 | (let* ((end-position (event-end event)) | |
302 | (window (nth 0 end-position)) | |
303 | (part (nth 4 end-position)) | |
304 | before-scroll) | |
2088cd64 | 305 | (cond ((eq part 'end-scroll)) |
cf4eb316 GM |
306 | (t |
307 | (with-current-buffer (window-buffer window) | |
308 | (setq before-scroll point-before-scroll)) | |
309 | (save-selected-window | |
310 | (select-window window) | |
311 | (setq before-scroll (or before-scroll (point))) | |
312 | (cond ((eq part 'above-handle) | |
313 | (scroll-up '-)) | |
314 | ((eq part 'below-handle) | |
315 | (scroll-up nil)) | |
d294c01f SM |
316 | ((eq part 'ratio) |
317 | (let* ((portion-whole (nth 2 end-position)) | |
318 | (lines (scroll-bar-scale portion-whole | |
319 | (1- (window-height))))) | |
320 | (scroll-up (cond ((not (zerop lines)) lines) | |
321 | ((< (car portion-whole) 0) -1) | |
322 | (t 1))))) | |
cf4eb316 GM |
323 | ((eq part 'up) |
324 | (scroll-up -1)) | |
325 | ((eq part 'down) | |
326 | (scroll-up 1)) | |
327 | ((eq part 'top) | |
328 | (set-window-start window (point-min))) | |
329 | ((eq part 'bottom) | |
330 | (goto-char (point-max)) | |
331 | (recenter)) | |
332 | ((eq part 'handle) | |
333 | (scroll-bar-drag-1 event)))) | |
334 | (sit-for 0) | |
cf4eb316 GM |
335 | (with-current-buffer (window-buffer window) |
336 | (setq point-before-scroll before-scroll)))))) | |
e532b016 | 337 | |
cf4eb316 GM |
338 | |
339 | \f | |
340 | ;;;; Bindings. | |
341 | ||
342 | ;;; For now, we'll set things up to work like xterm. | |
d08947c5 | 343 | (cond ((and (boundp 'x-toolkit-scroll-bars) x-toolkit-scroll-bars) |
cf4eb316 GM |
344 | (global-set-key [vertical-scroll-bar mouse-1] |
345 | 'scroll-bar-toolkit-scroll)) | |
346 | (t | |
347 | (global-set-key [vertical-scroll-bar mouse-1] | |
348 | 'scroll-bar-scroll-up) | |
349 | (global-set-key [vertical-scroll-bar drag-mouse-1] | |
350 | 'scroll-bar-scroll-up) | |
351 | (global-set-key [vertical-scroll-bar down-mouse-2] | |
352 | 'scroll-bar-drag) | |
353 | (global-set-key [vertical-scroll-bar mouse-3] | |
354 | 'scroll-bar-scroll-down) | |
355 | (global-set-key [vertical-scroll-bar drag-mouse-3] | |
356 | 'scroll-bar-scroll-down))) | |
6d62a90e JB |
357 | |
358 | \f | |
dc14eed2 | 359 | (provide 'scroll-bar) |
6d62a90e | 360 | |
ab5796a9 | 361 | ;;; arch-tag: 6f1d01d0-0b1e-4bf8-86db-d491e0f399f3 |
bf3c8a70 | 362 | ;;; scroll-bar.el ends here |