1;;; scroll-bar.el --- window system-independent scroll bar support 2 3;; Copyright (C) 1993, 1994, 1995, 1999, 2000, 2001, 2002, 2003, 4;; 2004, 2005, 2006, 2007 Free Software Foundation, Inc. 5 6;; Maintainer: FSF 7;; Keywords: hardware 8 9;; This file is part of GNU Emacs. 10 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. 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 22;; along with GNU Emacs; see the file COPYING. If not, write to the 23;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, 24;; Boston, MA 02110-1301, USA. 25 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 31;;; Code: 32 33(require 'mouse) 34 35 36;;;; Utilities. 37 38(defun scroll-bar-event-ratio (event) 39 "Given a scroll bar event EVENT, return the scroll bar position as a ratio. 40The value is a cons cell (PORTION . WHOLE) containing two integers 41whose ratio gives the event's vertical position in the scroll bar, with 0 42referring to the top and 1 to the bottom." 43 (nth 2 event)) 44 45(defun scroll-bar-scale (num-denom whole) 46 "Given a pair (NUM . DENOM) and WHOLE, return (/ (* NUM WHOLE) DENOM). 47This is handy for scaling a position on a scroll bar into real units, 48like buffer positions. If SCROLL-BAR-POS is the (PORTION . WHOLE) pair 49from a scroll bar event, then (scroll-bar-scale SCROLL-BAR-POS 50\(buffer-size)) is the position in the current buffer corresponding to 51that scroll bar position." 52 ;; We multiply before we divide to maintain precision. 53 ;; We use floating point because the product of a large buffer size 54 ;; with a large scroll bar portion can easily overflow a lisp int. 55 (truncate (/ (* (float (car num-denom)) whole) (cdr num-denom)))) 56 57(defun scroll-bar-columns (side) 58 "Return the width, measured in columns, of the vertical scrollbar on SIDE. 59SIDE 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 74 75;;;; Helpful functions for enabling and disabling scroll bars. 76 77(defvar scroll-bar-mode) 78(defvar previous-scroll-bar-mode nil) 79 80(defvar scroll-bar-mode-explicit nil 81 "Non-nil means `set-scroll-bar-mode' should really do something. 82This is nil while loading `scroll-bar.el', and t afterward.") 83 84(defun set-scroll-bar-mode-1 (ignore value) 85 (set-scroll-bar-mode value)) 86 87(defun set-scroll-bar-mode (value) 88 "Set `scroll-bar-mode' to VALUE and put the new value into effect." 89 (if scroll-bar-mode 90 (setq previous-scroll-bar-mode scroll-bar-mode)) 91 92 (setq scroll-bar-mode value) 93 94 (when scroll-bar-mode-explicit 95 ;; Apply it to default-frame-alist. 96 (let ((parameter (assq 'vertical-scroll-bars default-frame-alist))) 97 (if (consp parameter) 98 (setcdr parameter scroll-bar-mode) 99 (setq default-frame-alist 100 (cons (cons 'vertical-scroll-bars scroll-bar-mode) 101 default-frame-alist)))) 102 103 ;; Apply it to existing frames. 104 (let ((frames (frame-list))) 105 (while frames 106 (modify-frame-parameters 107 (car frames) 108 (list (cons 'vertical-scroll-bars scroll-bar-mode))) 109 (setq frames (cdr frames)))))) 110 111(defcustom scroll-bar-mode default-frame-scroll-bars 112 "*Specify whether to have vertical scroll bars, and on which side. 113Possible values are nil (no scroll bars), `left' (scroll bars on left) 114and `right' (scroll bars on right). 115To set this variable in a Lisp program, use `set-scroll-bar-mode' 116to make it take real effect. 117Setting the variable with a customization buffer also takes effect." 118 :type '(choice (const :tag "none (nil)" nil) 119 (const left) 120 (const right)) 121 :group 'frames 122 ;; The default value for :initialize would try to use :set 123 ;; when processing the file in cus-dep.el. 124 :initialize 'custom-initialize-default 125 :set 'set-scroll-bar-mode-1) 126 127;; We just set scroll-bar-mode, but that was the default. 128;; If it is set again, that is for real. 129(setq scroll-bar-mode-explicit t) 130 131(defun scroll-bar-mode (&optional flag) 132 "Toggle display of vertical scroll bars on all frames. 133This command applies to all frames that exist and frames to be 134created in the future. 135With a numeric argument, if the argument is negative, 136turn off scroll bars; otherwise, turn on scroll bars." 137 (interactive "P") 138 139 ;; Tweedle the variable according to the argument. 140 (set-scroll-bar-mode (if (if (null flag) 141 (not scroll-bar-mode) 142 (setq flag (prefix-numeric-value flag)) 143 (or (not (numberp flag)) (>= flag 0))) 144 (or previous-scroll-bar-mode 145 default-frame-scroll-bars)))) 146 147(defun toggle-scroll-bar (arg) 148 "Toggle whether or not the selected frame has vertical scroll bars. 149With arg, turn vertical scroll bars on if and only if arg is positive. 150The variable `scroll-bar-mode' controls which side the scroll bars are on 151when they are turned on; if it is nil, they go on the left." 152 (interactive "P") 153 (if (null arg) 154 (setq arg 155 (if (cdr (assq 'vertical-scroll-bars 156 (frame-parameters (selected-frame)))) 157 -1 1)) 158 (setq arg (prefix-numeric-value arg))) 159 (modify-frame-parameters 160 (selected-frame) 161 (list (cons 'vertical-scroll-bars 162 (if (> arg 0) 163 (or scroll-bar-mode default-frame-scroll-bars)))))) 164 165(defun toggle-horizontal-scroll-bar (arg) 166 "Toggle whether or not the selected frame has horizontal scroll bars. 167With arg, turn horizontal scroll bars on if and only if arg is positive. 168Horizontal scroll bars aren't implemented yet." 169 (interactive "P") 170 (error "Horizontal scroll bars aren't implemented yet")) 171 172;;;; Buffer navigation using the scroll bar. 173 174;;; This was used for up-events on button 2, but no longer. 175(defun scroll-bar-set-window-start (event) 176 "Set the window start according to where the scroll bar is dragged. 177EVENT should be a scroll bar click or drag event." 178 (interactive "e") 179 (let* ((end-position (event-end event)) 180 (window (nth 0 end-position)) 181 (portion-whole (nth 2 end-position))) 182 (save-excursion 183 (set-buffer (window-buffer window)) 184 (save-excursion 185 (goto-char (+ (point-min) 186 (scroll-bar-scale portion-whole 187 (- (point-max) (point-min))))) 188 (beginning-of-line) 189 (set-window-start window (point)))))) 190 191(defun scroll-bar-drag-position (portion-whole) 192 "Calculate new window start for drag event." 193 (save-excursion 194 (goto-char (+ (point-min) 195 (scroll-bar-scale portion-whole 196 (- (point-max) (point-min))))) 197 (beginning-of-line) 198 (point))) 199 200(defun scroll-bar-maybe-set-window-start (event) 201 "Set the window start according to where the scroll bar is dragged. 202Only change window start if the new start is substantially different. 203EVENT should be a scroll bar click or drag event." 204 (interactive "e") 205 (let* ((end-position (event-end event)) 206 (window (nth 0 end-position)) 207 (portion-whole (nth 2 end-position)) 208 (next-portion-whole (cons (1+ (car portion-whole)) 209 (cdr portion-whole))) 210 portion-start 211 next-portion-start 212 (current-start (window-start window))) 213 (save-excursion 214 (set-buffer (window-buffer window)) 215 (setq portion-start (scroll-bar-drag-position portion-whole)) 216 (setq next-portion-start (max 217 (scroll-bar-drag-position next-portion-whole) 218 (1+ portion-start))) 219 (if (or (>= current-start next-portion-start) 220 (< current-start portion-start)) 221 (set-window-start window portion-start) 222 ;; Always set window start, to ensure scroll bar position is updated. 223 (set-window-start window current-start))))) 224 225;; Scroll the window to the proper position for EVENT. 226(defun scroll-bar-drag-1 (event) 227 (let* ((start-position (event-start event)) 228 (window (nth 0 start-position)) 229 (portion-whole (nth 2 start-position))) 230 (save-excursion 231 (set-buffer (window-buffer window)) 232 ;; Calculate position relative to the accessible part of the buffer. 233 (goto-char (+ (point-min) 234 (scroll-bar-scale portion-whole 235 (- (point-max) (point-min))))) 236 (vertical-motion 0 window) 237 (set-window-start window (point))))) 238 239(defun scroll-bar-drag (event) 240 "Scroll the window by dragging the scroll bar slider. 241If you click outside the slider, the window scrolls to bring the slider there." 242 (interactive "e") 243 (let* (done 244 (echo-keystrokes 0) 245 (end-position (event-end event)) 246 (window (nth 0 end-position)) 247 (before-scroll)) 248 (with-current-buffer (window-buffer window) 249 (setq before-scroll point-before-scroll)) 250 (save-selected-window 251 (select-window window) 252 (setq before-scroll 253 (or before-scroll (point)))) 254 (scroll-bar-drag-1 event) 255 (track-mouse 256 (while (not done) 257 (setq event (read-event)) 258 (if (eq (car-safe event) 'mouse-movement) 259 (setq event (read-event))) 260 (cond ((eq (car-safe event) 'scroll-bar-movement) 261 (scroll-bar-drag-1 event)) 262 (t 263 ;; Exit when we get the drag event; ignore that event. 264 (setq done t))))) 265 (sit-for 0) 266 (with-current-buffer (window-buffer window) 267 (setq point-before-scroll before-scroll)))) 268 269(defun scroll-bar-scroll-down (event) 270 "Scroll the window's top line down to the location of the scroll bar click. 271EVENT should be a scroll bar click." 272 (interactive "e") 273 (let* ((end-position (event-end event)) 274 (window (nth 0 end-position)) 275 (before-scroll)) 276 (with-current-buffer (window-buffer window) 277 (setq before-scroll point-before-scroll)) 278 (unwind-protect 279 (save-selected-window 280 (let ((portion-whole (nth 2 end-position))) 281 (select-window window) 282 (setq before-scroll 283 (or before-scroll (point))) 284 (scroll-down 285 (scroll-bar-scale portion-whole (1- (window-height))))) 286 (sit-for 0)) 287 (with-current-buffer (window-buffer window) 288 (setq point-before-scroll before-scroll))))) 289 290(defun scroll-bar-scroll-up (event) 291 "Scroll the line next to the scroll bar click to the top of the window. 292EVENT should be a scroll bar click." 293 (interactive "e") 294 (let* ((end-position (event-end event)) 295 (window (nth 0 end-position)) 296 (before-scroll)) 297 (with-current-buffer (window-buffer window) 298 (setq before-scroll point-before-scroll)) 299 (unwind-protect 300 (save-selected-window 301 (let ((portion-whole (nth 2 end-position))) 302 (select-window window) 303 (setq before-scroll 304 (or before-scroll (point))) 305 (scroll-up 306 (scroll-bar-scale portion-whole (1- (window-height))))) 307 (sit-for 0)) 308 (with-current-buffer (window-buffer window) 309 (setq point-before-scroll before-scroll))))) 310 311 312;;; Tookit scroll bars. 313 314(defun scroll-bar-toolkit-scroll (event) 315 (interactive "e") 316 (let* ((end-position (event-end event)) 317 (window (nth 0 end-position)) 318 (part (nth 4 end-position)) 319 before-scroll) 320 (cond ((eq part 'end-scroll)) 321 (t 322 (with-current-buffer (window-buffer window) 323 (setq before-scroll point-before-scroll)) 324 (save-selected-window 325 (select-window window) 326 (setq before-scroll (or before-scroll (point))) 327 (cond ((eq part 'above-handle) 328 (scroll-up '-)) 329 ((eq part 'below-handle) 330 (scroll-up nil)) 331 ((eq part 'ratio) 332 (let* ((portion-whole (nth 2 end-position)) 333 (lines (scroll-bar-scale portion-whole 334 (1- (window-height))))) 335 (scroll-up (cond ((not (zerop lines)) lines) 336 ((< (car portion-whole) 0) -1) 337 (t 1))))) 338 ((eq part 'up) 339 (scroll-up -1)) 340 ((eq part 'down) 341 (scroll-up 1)) 342 ((eq part 'top) 343 (set-window-start window (point-min))) 344 ((eq part 'bottom) 345 (goto-char (point-max)) 346 (recenter)) 347 ((eq part 'handle) 348 (scroll-bar-drag-1 event)))) 349 (sit-for 0) 350 (with-current-buffer (window-buffer window) 351 (setq point-before-scroll before-scroll)))))) 352 353 354 355;;;; Bindings. 356 357;;; For now, we'll set things up to work like xterm. 358(cond ((and (boundp 'x-toolkit-scroll-bars) x-toolkit-scroll-bars) 359 (global-set-key [vertical-scroll-bar mouse-1] 360 'scroll-bar-toolkit-scroll)) 361 (t 362 (global-set-key [vertical-scroll-bar mouse-1] 363 'scroll-bar-scroll-up) 364 (global-set-key [vertical-scroll-bar drag-mouse-1] 365 'scroll-bar-scroll-up) 366 (global-set-key [vertical-scroll-bar down-mouse-2] 367 'scroll-bar-drag) 368 (global-set-key [vertical-scroll-bar mouse-3] 369 'scroll-bar-scroll-down) 370 (global-set-key [vertical-scroll-bar drag-mouse-3] 371 'scroll-bar-scroll-down))) 372 373 374(provide 'scroll-bar) 375 376;;; arch-tag: 6f1d01d0-0b1e-4bf8-86db-d491e0f399f3 377;;; scroll-bar.el ends here 378