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aae56ea7 | 1 | ;;; scroll-bar.el --- window system-independent scroll bar support. |
6d62a90e JB |
2 | |
3 | ;;; Copyright (C) 1993 Free Software Foundation, Inc. | |
4 | ||
5 | ;; Maintainer: FSF | |
6 | ;; Keywords: hardware | |
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 | |
22 | ;;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. | |
23 | ||
76550a57 ER |
24 | ;;; Code: |
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. | |
30 | ;;; Code: | |
31 | ||
dbc4e1c1 JB |
32 | (require 'mouse) |
33 | ||
6d62a90e JB |
34 | \f |
35 | ;;;; Utilities. | |
36 | ||
bf3c8a70 | 37 | (defun scroll-bar-scale (num-denom whole) |
6d62a90e | 38 | "Given a pair (NUM . DENOM) and WHOLE, return (/ (* NUM WHOLE) DENOM). |
bf3c8a70 JB |
39 | This is handy for scaling a position on a scroll bar into real units, |
40 | like buffer positions. If SCROLL-BAR-POS is the (PORTION . WHOLE) pair | |
41 | from a scroll bar event, then (scroll-bar-scale SCROLL-BAR-POS | |
6d62a90e | 42 | \(buffer-size)) is the position in the current buffer corresponding to |
bf3c8a70 | 43 | that scroll bar position." |
6d62a90e JB |
44 | ;; We multiply before we divide to maintain precision. |
45 | ;; We use floating point because the product of a large buffer size | |
bf3c8a70 | 46 | ;; with a large scroll bar portion can easily overflow a lisp int. |
6d62a90e JB |
47 | (truncate (/ (* (float (car num-denom)) whole) (cdr num-denom)))) |
48 | ||
49 | \f | |
fe48f821 JB |
50 | ;;;; Helpful functions for enabling and disabling scroll bars. |
51 | (defvar scroll-bar-mode nil) | |
52 | ||
53 | (defun scroll-bar-mode (flag) | |
54 | "Toggle display of vertical scroll bars on each frame. | |
55 | This command applies to all frames that exist and frames to be | |
56 | created in the future. | |
57 | With a numeric argument, if the argument is negative, | |
58 | turn off scroll bars; otherwise, turn on scroll bars." | |
59 | (interactive "P") | |
60 | (setq scroll-bar-mode (if (null flag) (not scroll-bar-mode) | |
61 | (or (not (numberp flag)) (>= flag 0)))) | |
62 | (mapcar | |
63 | (function | |
64 | (lambda (param-name) | |
65 | (let ((parameter (assq param-name default-frame-alist))) | |
66 | (if (consp parameter) | |
67 | (setcdr parameter scroll-bar-mode) | |
68 | (setq default-frame-alist | |
69 | (cons (cons param-name scroll-bar-mode) | |
70 | default-frame-alist)))))) | |
bf3c8a70 | 71 | '(vertical-scroll-bars horizontal-scroll-bars)) |
fe48f821 JB |
72 | (let ((frames (frame-list))) |
73 | (while frames | |
74 | (modify-frame-parameters | |
75 | (car frames) | |
bf3c8a70 JB |
76 | (list (cons 'vertical-scroll-bars scroll-bar-mode) |
77 | (cons 'horizontal-scroll-bars scroll-bar-mode))) | |
fe48f821 JB |
78 | (setq frames (cdr frames))))) |
79 | \f | |
bf3c8a70 | 80 | ;;;; Buffer navigation using the scroll bar. |
6d62a90e | 81 | |
e532b016 | 82 | ;;; This was used for up-events on button 2, but no longer. |
bf3c8a70 JB |
83 | (defun scroll-bar-set-window-start (event) |
84 | "Set the window start according to where the scroll bar is dragged. | |
85 | EVENT should be a scroll bar click or drag event." | |
6d62a90e | 86 | (interactive "e") |
dbc4e1c1 | 87 | (let* ((end-position (event-end event)) |
6d62a90e JB |
88 | (window (nth 0 end-position)) |
89 | (portion-whole (nth 2 end-position))) | |
90 | (save-excursion | |
91 | (set-buffer (window-buffer window)) | |
92 | (save-excursion | |
bf3c8a70 | 93 | (goto-char (scroll-bar-scale portion-whole (buffer-size))) |
6d62a90e JB |
94 | (beginning-of-line) |
95 | (set-window-start window (point)))))) | |
96 | ||
e532b016 RS |
97 | ;; Scroll the window to the proper position for EVENT. |
98 | (defun scroll-bar-drag-1 (event) | |
99 | (let* ((start-position (event-start event)) | |
100 | (window (nth 0 start-position)) | |
101 | (portion-whole (nth 2 start-position))) | |
102 | (save-excursion | |
103 | (set-buffer (window-buffer window)) | |
104 | (goto-char (scroll-bar-scale portion-whole (buffer-size))) | |
105 | (beginning-of-line) | |
106 | (set-window-start window (point))))) | |
107 | ||
108 | (defun scroll-bar-drag (event) | |
109 | "Scroll the window by dragging the scroll bar slider. | |
110 | If you click outside the slider, the window scrolls to bring the slider there." | |
111 | (interactive "e") | |
112 | (let* (done) | |
113 | (scroll-bar-drag-1 event) | |
114 | (track-mouse | |
115 | (while (not done) | |
116 | (setq event (read-event)) | |
117 | (if (eq (car-safe event) 'mouse-movement) | |
118 | (setq event (read-event))) | |
119 | (cond ((eq (car-safe event) 'scroll-bar-movement) | |
120 | (scroll-bar-drag-1 event)) | |
121 | (t | |
122 | ;; Exit when we get the drag event; ignore that event. | |
123 | (setq done t))))))) | |
124 | ||
bf3c8a70 JB |
125 | (defun scroll-bar-scroll-down (event) |
126 | "Scroll the window's top line down to the location of the scroll bar click. | |
127 | EVENT should be a scroll bar click." | |
6d62a90e JB |
128 | (interactive "e") |
129 | (let ((old-selected-window (selected-window))) | |
130 | (unwind-protect | |
131 | (progn | |
dbc4e1c1 | 132 | (let* ((end-position (event-end event)) |
6d62a90e JB |
133 | (window (nth 0 end-position)) |
134 | (portion-whole (nth 2 end-position))) | |
135 | (select-window window) | |
136 | (scroll-down | |
bf3c8a70 | 137 | (scroll-bar-scale portion-whole (1- (window-height)))))) |
6d62a90e JB |
138 | (select-window old-selected-window)))) |
139 | ||
bf3c8a70 JB |
140 | (defun scroll-bar-scroll-up (event) |
141 | "Scroll the line next to the scroll bar click to the top of the window. | |
142 | EVENT should be a scroll bar click." | |
6d62a90e JB |
143 | (interactive "e") |
144 | (let ((old-selected-window (selected-window))) | |
145 | (unwind-protect | |
146 | (progn | |
dbc4e1c1 | 147 | (let* ((end-position (event-end event)) |
6d62a90e JB |
148 | (window (nth 0 end-position)) |
149 | (portion-whole (nth 2 end-position))) | |
150 | (select-window window) | |
151 | (scroll-up | |
bf3c8a70 | 152 | (scroll-bar-scale portion-whole (1- (window-height)))))) |
6d62a90e JB |
153 | (select-window old-selected-window)))) |
154 | ||
155 | \f | |
156 | ;;;; Bindings. | |
157 | ||
158 | ;;; For now, we'll set things up to work like xterm. | |
bf3c8a70 JB |
159 | (global-set-key [vertical-scroll-bar mouse-1] 'scroll-bar-scroll-up) |
160 | (global-set-key [vertical-scroll-bar drag-mouse-1] 'scroll-bar-scroll-up) | |
6d62a90e | 161 | |
e532b016 RS |
162 | (global-set-key [vertical-scroll-bar down-mouse-2] 'scroll-bar-drag) |
163 | ||
bf3c8a70 JB |
164 | (global-set-key [vertical-scroll-bar mouse-3] 'scroll-bar-scroll-down) |
165 | (global-set-key [vertical-scroll-bar drag-mouse-3] 'scroll-bar-scroll-down) | |
6d62a90e JB |
166 | |
167 | \f | |
dc14eed2 | 168 | (provide 'scroll-bar) |
6d62a90e | 169 | |
bf3c8a70 | 170 | ;;; scroll-bar.el ends here |