Commit | Line | Data |
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55535639 | 1 | ;;; scroll-bar.el --- window system-independent scroll bar support |
6d62a90e | 2 | |
0d30b337 | 3 | ;; Copyright (C) 1993, 1994, 1995, 1999, 2000, 2001, 2002, 2003, |
aaef169d | 4 | ;; 2004, 2005, 2006 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 | |
086add15 LK |
23 | ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, |
24 | ;; Boston, MA 02110-1301, 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 | ||
9fd76d04 MY |
57 | (defun scroll-bar-columns (side) |
58 | "Return the width, measured in columns, of the vertical scrollbar on SIDE. | |
59 | SIDE must be the symbol `left' or `right'." | |
60 | (let* ((wsb (window-scroll-bars)) | |
61 | (vtype (nth 2 wsb)) | |
62 | (cols (nth 1 wsb))) | |
63 | (cond | |
64 | ((not (memq side '(left right))) | |
65 | (error "`left' or `right' expected instead of %S" side)) | |
66 | ((and (eq vtype side) cols)) | |
67 | ((eq (frame-parameter nil 'vertical-scroll-bars) side) | |
68 | ;; nil means it's a non-toolkit scroll bar, and its width in | |
69 | ;; columns is 14 pixels rounded up. | |
70 | (ceiling (or (frame-parameter nil 'scroll-bar-width) 14) | |
71 | (frame-char-width))) | |
72 | (0)))) | |
73 | ||
6d62a90e | 74 | \f |
fe48f821 | 75 | ;;;; Helpful functions for enabling and disabling scroll bars. |
fe48f821 | 76 | |
1064fe38 RS |
77 | (defvar scroll-bar-mode) |
78 | ||
2124851f RS |
79 | (defvar scroll-bar-mode-explicit nil |
80 | "Non-nil means `set-scroll-bar-mode' should really do something. | |
81 | This is nil while loading `scroll-bar.el', and t afterward.") | |
82 | ||
e4b201bb KH |
83 | (defun set-scroll-bar-mode-1 (ignore value) |
84 | (set-scroll-bar-mode value)) | |
85 | ||
86 | (defun set-scroll-bar-mode (value) | |
04c34f2e RS |
87 | "Set `scroll-bar-mode' to VALUE and put the new value into effect." |
88 | (setq scroll-bar-mode value) | |
89 | ||
2124851f RS |
90 | (when scroll-bar-mode-explicit |
91 | ;; Apply it to default-frame-alist. | |
92 | (let ((parameter (assq 'vertical-scroll-bars default-frame-alist))) | |
93 | (if (consp parameter) | |
94 | (setcdr parameter scroll-bar-mode) | |
95 | (setq default-frame-alist | |
96 | (cons (cons 'vertical-scroll-bars scroll-bar-mode) | |
97 | default-frame-alist)))) | |
98 | ||
99 | ;; Apply it to existing frames. | |
100 | (let ((frames (frame-list))) | |
101 | (while frames | |
102 | (modify-frame-parameters | |
103 | (car frames) | |
104 | (list (cons 'vertical-scroll-bars scroll-bar-mode))) | |
105 | (setq frames (cdr frames)))))) | |
04c34f2e | 106 | |
61f2fe7b | 107 | (defcustom scroll-bar-mode default-frame-scroll-bars |
04c34f2e RS |
108 | "*Specify whether to have vertical scroll bars, and on which side. |
109 | Possible values are nil (no scroll bars), `left' (scroll bars on left) | |
110 | and `right' (scroll bars on right). | |
463deb66 RS |
111 | To set this variable in a Lisp program, use `set-scroll-bar-mode' |
112 | to make it take real effect. | |
113 | Setting the variable with a customization buffer also takes effect." | |
64453f32 | 114 | :type '(choice (const :tag "none (nil)" nil) |
04c34f2e RS |
115 | (const left) |
116 | (const right)) | |
117 | :group 'frames | |
2669fbfb RS |
118 | ;; The default value for :initialize would try to use :set |
119 | ;; when processing the file in cus-dep.el. | |
120 | :initialize 'custom-initialize-default | |
e4b201bb | 121 | :set 'set-scroll-bar-mode-1) |
04c34f2e | 122 | |
2124851f RS |
123 | ;; We just set scroll-bar-mode, but that was the default. |
124 | ;; If it is set again, that is for real. | |
125 | (setq scroll-bar-mode-explicit t) | |
126 | ||
b1ad7c13 | 127 | (defun scroll-bar-mode (&optional flag) |
04c34f2e | 128 | "Toggle display of vertical scroll bars on all frames. |
fe48f821 JB |
129 | This command applies to all frames that exist and frames to be |
130 | created in the future. | |
131 | With a numeric argument, if the argument is negative, | |
132 | turn off scroll bars; otherwise, turn on scroll bars." | |
133 | (interactive "P") | |
ada464a7 | 134 | |
04c34f2e | 135 | ;; Tweedle the variable according to the argument. |
61f2fe7b KS |
136 | (set-scroll-bar-mode (if (if (null flag) |
137 | (not scroll-bar-mode) | |
138 | (setq flag (prefix-numeric-value flag)) | |
139 | (or (not (numberp flag)) (>= flag 0))) | |
140 | default-frame-scroll-bars))) | |
04c34f2e RS |
141 | |
142 | (defun toggle-scroll-bar (arg) | |
143 | "Toggle whether or not the selected frame has vertical scroll bars. | |
144 | With arg, turn vertical scroll bars on if and only if arg is positive. | |
145 | The variable `scroll-bar-mode' controls which side the scroll bars are on | |
146 | when they are turned on; if it is nil, they go on the left." | |
147 | (interactive "P") | |
148 | (if (null arg) | |
149 | (setq arg | |
150 | (if (cdr (assq 'vertical-scroll-bars | |
151 | (frame-parameters (selected-frame)))) | |
19c6feac KH |
152 | -1 1)) |
153 | (setq arg (prefix-numeric-value arg))) | |
1032e793 GV |
154 | (modify-frame-parameters |
155 | (selected-frame) | |
156 | (list (cons 'vertical-scroll-bars | |
157 | (if (> arg 0) | |
61f2fe7b | 158 | (or scroll-bar-mode default-frame-scroll-bars)))))) |
04c34f2e RS |
159 | |
160 | (defun toggle-horizontal-scroll-bar (arg) | |
161 | "Toggle whether or not the selected frame has horizontal scroll bars. | |
162 | With arg, turn horizontal scroll bars on if and only if arg is positive. | |
163 | Horizontal scroll bars aren't implemented yet." | |
164 | (interactive "P") | |
165 | (error "Horizontal scroll bars aren't implemented yet")) | |
fe48f821 | 166 | \f |
bf3c8a70 | 167 | ;;;; Buffer navigation using the scroll bar. |
6d62a90e | 168 | |
e532b016 | 169 | ;;; This was used for up-events on button 2, but no longer. |
bf3c8a70 JB |
170 | (defun scroll-bar-set-window-start (event) |
171 | "Set the window start according to where the scroll bar is dragged. | |
172 | EVENT should be a scroll bar click or drag event." | |
6d62a90e | 173 | (interactive "e") |
dbc4e1c1 | 174 | (let* ((end-position (event-end event)) |
6d62a90e JB |
175 | (window (nth 0 end-position)) |
176 | (portion-whole (nth 2 end-position))) | |
177 | (save-excursion | |
178 | (set-buffer (window-buffer window)) | |
179 | (save-excursion | |
4cad38d5 JB |
180 | (goto-char (+ (point-min) |
181 | (scroll-bar-scale portion-whole | |
182 | (- (point-max) (point-min))))) | |
6d62a90e JB |
183 | (beginning-of-line) |
184 | (set-window-start window (point)))))) | |
185 | ||
aeee66be RS |
186 | (defun scroll-bar-drag-position (portion-whole) |
187 | "Calculate new window start for drag event." | |
188 | (save-excursion | |
189 | (goto-char (+ (point-min) | |
190 | (scroll-bar-scale portion-whole | |
191 | (- (point-max) (point-min))))) | |
192 | (beginning-of-line) | |
193 | (point))) | |
194 | ||
195 | (defun scroll-bar-maybe-set-window-start (event) | |
196 | "Set the window start according to where the scroll bar is dragged. | |
197 | Only change window start if the new start is substantially different. | |
198 | EVENT should be a scroll bar click or drag event." | |
199 | (interactive "e") | |
200 | (let* ((end-position (event-end event)) | |
201 | (window (nth 0 end-position)) | |
202 | (portion-whole (nth 2 end-position)) | |
203 | (next-portion-whole (cons (1+ (car portion-whole)) | |
204 | (cdr portion-whole))) | |
205 | portion-start | |
206 | next-portion-start | |
207 | (current-start (window-start window))) | |
208 | (save-excursion | |
209 | (set-buffer (window-buffer window)) | |
210 | (setq portion-start (scroll-bar-drag-position portion-whole)) | |
211 | (setq next-portion-start (max | |
212 | (scroll-bar-drag-position next-portion-whole) | |
213 | (1+ portion-start))) | |
15655694 | 214 | (if (or (>= current-start next-portion-start) |
aeee66be | 215 | (< current-start portion-start)) |
9c005c65 KH |
216 | (set-window-start window portion-start) |
217 | ;; Always set window start, to ensure scroll bar position is updated. | |
218 | (set-window-start window current-start))))) | |
aeee66be | 219 | |
e532b016 RS |
220 | ;; Scroll the window to the proper position for EVENT. |
221 | (defun scroll-bar-drag-1 (event) | |
222 | (let* ((start-position (event-start event)) | |
223 | (window (nth 0 start-position)) | |
224 | (portion-whole (nth 2 start-position))) | |
225 | (save-excursion | |
226 | (set-buffer (window-buffer window)) | |
d2ae6f7e RS |
227 | ;; Calculate position relative to the accessible part of the buffer. |
228 | (goto-char (+ (point-min) | |
229 | (scroll-bar-scale portion-whole | |
230 | (- (point-max) (point-min))))) | |
9d7ab3f0 | 231 | (vertical-motion 0 window) |
e532b016 RS |
232 | (set-window-start window (point))))) |
233 | ||
234 | (defun scroll-bar-drag (event) | |
235 | "Scroll the window by dragging the scroll bar slider. | |
236 | If you click outside the slider, the window scrolls to bring the slider there." | |
237 | (interactive "e") | |
c782bea5 | 238 | (let* (done |
cb183ca0 RS |
239 | (echo-keystrokes 0) |
240 | (end-position (event-end event)) | |
241 | (window (nth 0 end-position)) | |
242 | (before-scroll)) | |
243 | (with-current-buffer (window-buffer window) | |
244 | (setq before-scroll point-before-scroll)) | |
245 | (save-selected-window | |
246 | (select-window window) | |
247 | (setq before-scroll | |
248 | (or before-scroll (point)))) | |
249 | (scroll-bar-drag-1 event) | |
250 | (track-mouse | |
251 | (while (not done) | |
252 | (setq event (read-event)) | |
253 | (if (eq (car-safe event) 'mouse-movement) | |
254 | (setq event (read-event))) | |
255 | (cond ((eq (car-safe event) 'scroll-bar-movement) | |
256 | (scroll-bar-drag-1 event)) | |
257 | (t | |
258 | ;; Exit when we get the drag event; ignore that event. | |
259 | (setq done t))))) | |
260 | (sit-for 0) | |
261 | (with-current-buffer (window-buffer window) | |
262 | (setq point-before-scroll before-scroll)))) | |
e532b016 | 263 | |
bf3c8a70 JB |
264 | (defun scroll-bar-scroll-down (event) |
265 | "Scroll the window's top line down to the location of the scroll bar click. | |
266 | EVENT should be a scroll bar click." | |
6d62a90e | 267 | (interactive "e") |
cb183ca0 RS |
268 | (let* ((end-position (event-end event)) |
269 | (window (nth 0 end-position)) | |
270 | (before-scroll)) | |
271 | (with-current-buffer (window-buffer window) | |
272 | (setq before-scroll point-before-scroll)) | |
def7db1d KH |
273 | (unwind-protect |
274 | (save-selected-window | |
275 | (let ((portion-whole (nth 2 end-position))) | |
276 | (select-window window) | |
277 | (setq before-scroll | |
278 | (or before-scroll (point))) | |
279 | (scroll-down | |
280 | (scroll-bar-scale portion-whole (1- (window-height))))) | |
281 | (sit-for 0)) | |
282 | (with-current-buffer (window-buffer window) | |
283 | (setq point-before-scroll before-scroll))))) | |
6d62a90e | 284 | |
bf3c8a70 JB |
285 | (defun scroll-bar-scroll-up (event) |
286 | "Scroll the line next to the scroll bar click to the top of the window. | |
287 | EVENT should be a scroll bar click." | |
6d62a90e | 288 | (interactive "e") |
cb183ca0 RS |
289 | (let* ((end-position (event-end event)) |
290 | (window (nth 0 end-position)) | |
291 | (before-scroll)) | |
292 | (with-current-buffer (window-buffer window) | |
293 | (setq before-scroll point-before-scroll)) | |
def7db1d KH |
294 | (unwind-protect |
295 | (save-selected-window | |
296 | (let ((portion-whole (nth 2 end-position))) | |
297 | (select-window window) | |
298 | (setq before-scroll | |
299 | (or before-scroll (point))) | |
300 | (scroll-up | |
301 | (scroll-bar-scale portion-whole (1- (window-height))))) | |
302 | (sit-for 0)) | |
303 | (with-current-buffer (window-buffer window) | |
304 | (setq point-before-scroll before-scroll))))) | |
6d62a90e JB |
305 | |
306 | \f | |
cf4eb316 | 307 | ;;; Tookit scroll bars. |
6d62a90e | 308 | |
cf4eb316 GM |
309 | (defun scroll-bar-toolkit-scroll (event) |
310 | (interactive "e") | |
311 | (let* ((end-position (event-end event)) | |
312 | (window (nth 0 end-position)) | |
313 | (part (nth 4 end-position)) | |
314 | before-scroll) | |
2088cd64 | 315 | (cond ((eq part 'end-scroll)) |
cf4eb316 GM |
316 | (t |
317 | (with-current-buffer (window-buffer window) | |
318 | (setq before-scroll point-before-scroll)) | |
319 | (save-selected-window | |
320 | (select-window window) | |
321 | (setq before-scroll (or before-scroll (point))) | |
322 | (cond ((eq part 'above-handle) | |
323 | (scroll-up '-)) | |
324 | ((eq part 'below-handle) | |
325 | (scroll-up nil)) | |
d294c01f SM |
326 | ((eq part 'ratio) |
327 | (let* ((portion-whole (nth 2 end-position)) | |
328 | (lines (scroll-bar-scale portion-whole | |
329 | (1- (window-height))))) | |
330 | (scroll-up (cond ((not (zerop lines)) lines) | |
331 | ((< (car portion-whole) 0) -1) | |
332 | (t 1))))) | |
cf4eb316 GM |
333 | ((eq part 'up) |
334 | (scroll-up -1)) | |
335 | ((eq part 'down) | |
336 | (scroll-up 1)) | |
337 | ((eq part 'top) | |
338 | (set-window-start window (point-min))) | |
339 | ((eq part 'bottom) | |
340 | (goto-char (point-max)) | |
341 | (recenter)) | |
342 | ((eq part 'handle) | |
343 | (scroll-bar-drag-1 event)))) | |
344 | (sit-for 0) | |
cf4eb316 GM |
345 | (with-current-buffer (window-buffer window) |
346 | (setq point-before-scroll before-scroll)))))) | |
e532b016 | 347 | |
cf4eb316 GM |
348 | |
349 | \f | |
350 | ;;;; Bindings. | |
351 | ||
352 | ;;; For now, we'll set things up to work like xterm. | |
d08947c5 | 353 | (cond ((and (boundp 'x-toolkit-scroll-bars) x-toolkit-scroll-bars) |
cf4eb316 GM |
354 | (global-set-key [vertical-scroll-bar mouse-1] |
355 | 'scroll-bar-toolkit-scroll)) | |
356 | (t | |
357 | (global-set-key [vertical-scroll-bar mouse-1] | |
358 | 'scroll-bar-scroll-up) | |
359 | (global-set-key [vertical-scroll-bar drag-mouse-1] | |
360 | 'scroll-bar-scroll-up) | |
361 | (global-set-key [vertical-scroll-bar down-mouse-2] | |
362 | 'scroll-bar-drag) | |
363 | (global-set-key [vertical-scroll-bar mouse-3] | |
364 | 'scroll-bar-scroll-down) | |
365 | (global-set-key [vertical-scroll-bar drag-mouse-3] | |
366 | 'scroll-bar-scroll-down))) | |
6d62a90e JB |
367 | |
368 | \f | |
dc14eed2 | 369 | (provide 'scroll-bar) |
6d62a90e | 370 | |
ab5796a9 | 371 | ;;; arch-tag: 6f1d01d0-0b1e-4bf8-86db-d491e0f399f3 |
bf3c8a70 | 372 | ;;; scroll-bar.el ends here |