[bpt/emacs.git] / lisp / scroll-bar.el

;;; scroll-bar.el --- window system-independent scroll bar support

;; Copyright (C) 1993, 1994, 1995, 1999, 2000, 2001, 2003
;;  Free Software Foundation, Inc.

;; Maintainer: FSF
;; Keywords: hardware

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Commentary:

;; Window-system-independent bindings of mouse clicks on the scroll bar.
;; Presently emulates the scroll-bar behavior of xterm.

;;; Code:

(require 'mouse)

\f
;;;; Utilities.

(defun scroll-bar-event-ratio (event)
  "Given a scroll bar event EVENT, return the scroll bar position as a ratio.
The value is a cons cell (PORTION . WHOLE) containing two integers
whose ratio gives the event's vertical position in the scroll bar, with 0
referring to the top and 1 to the bottom."
  (nth 2 event))

(defun scroll-bar-scale (num-denom whole)
  "Given a pair (NUM . DENOM) and WHOLE, return (/ (* NUM WHOLE) DENOM).
This is handy for scaling a position on a scroll bar into real units,
like buffer positions.  If SCROLL-BAR-POS is the (PORTION . WHOLE) pair
from a scroll bar event, then (scroll-bar-scale SCROLL-BAR-POS
\(buffer-size)) is the position in the current buffer corresponding to
that scroll bar position."
  ;; We multiply before we divide to maintain precision.
  ;; We use floating point because the product of a large buffer size
  ;; with a large scroll bar portion can easily overflow a lisp int.
  (truncate (/ (* (float (car num-denom)) whole) (cdr num-denom))))

\f
;;;; Helpful functions for enabling and disabling scroll bars.

(defvar scroll-bar-mode)

(defvar scroll-bar-mode-explicit nil
  "Non-nil means `set-scroll-bar-mode' should really do something.
This is nil while loading `scroll-bar.el', and t afterward.")

(defun set-scroll-bar-mode-1 (ignore value)
  (set-scroll-bar-mode value))

(defun set-scroll-bar-mode (value)
  "Set `scroll-bar-mode' to VALUE and put the new value into effect."
  (setq scroll-bar-mode value)

  (when scroll-bar-mode-explicit
    ;; Apply it to default-frame-alist.
    (let ((parameter (assq 'vertical-scroll-bars default-frame-alist)))
      (if (consp parameter)
	  (setcdr parameter scroll-bar-mode)
	(setq default-frame-alist
	      (cons (cons 'vertical-scroll-bars scroll-bar-mode)
		    default-frame-alist))))

    ;; Apply it to existing frames.
    (let ((frames (frame-list)))
      (while frames
	(modify-frame-parameters
	 (car frames)
	 (list (cons 'vertical-scroll-bars scroll-bar-mode)))
	(setq frames (cdr frames))))))

(defcustom scroll-bar-mode
  (cond ((eq system-type 'windows-nt) 'right)
	((featurep 'mac-carbon) 'right)
	(t 'left))
  "*Specify whether to have vertical scroll bars, and on which side.
Possible values are nil (no scroll bars), `left' (scroll bars on left)
and `right' (scroll bars on right).
To set this variable in a Lisp program, use `set-scroll-bar-mode'
to make it take real effect.
Setting the variable with a customization buffer also takes effect."
  :type '(choice (const :tag "none (nil)" nil)
		 (const left)
		 (const right))
  :group 'frames
  ;; The default value for :initialize would try to use :set
  ;; when processing the file in cus-dep.el.
  :initialize 'custom-initialize-default
  :set 'set-scroll-bar-mode-1)

;; We just set scroll-bar-mode, but that was the default.
;; If it is set again, that is for real.
(setq scroll-bar-mode-explicit t)

(defun scroll-bar-mode (&optional flag)
  "Toggle display of vertical scroll bars on all frames.
This command applies to all frames that exist and frames to be
created in the future.
With a numeric argument, if the argument is negative,
turn off scroll bars; otherwise, turn on scroll bars."
  (interactive "P")
  (if flag (setq flag (prefix-numeric-value flag)))

  ;; Tweedle the variable according to the argument.
  (set-scroll-bar-mode (if (null flag) (not scroll-bar-mode)
			 (and (or (not (numberp flag)) (>= flag 0))
			      (cond ((eq system-type 'windows-nt) 'right)
				    ((featurep 'mac-carbon) 'right)
				    (t 'left))))))

(defun toggle-scroll-bar (arg)
  "Toggle whether or not the selected frame has vertical scroll bars.
With arg, turn vertical scroll bars on if and only if arg is positive.
The variable `scroll-bar-mode' controls which side the scroll bars are on
when they are turned on; if it is nil, they go on the left."
  (interactive "P")
  (if (null arg)
      (setq arg
	    (if (cdr (assq 'vertical-scroll-bars
			   (frame-parameters (selected-frame))))
		-1 1))
    (setq arg (prefix-numeric-value arg)))
  (modify-frame-parameters
   (selected-frame)
   (list (cons 'vertical-scroll-bars
	       (if (> arg 0)
		   (or scroll-bar-mode
		       (cond ((eq system-type 'windows-nt) 'right)
			     ((featurep 'mac-carbon) 'right)
			     (t 'left))))))))

(defun toggle-horizontal-scroll-bar (arg)
  "Toggle whether or not the selected frame has horizontal scroll bars.
With arg, turn horizontal scroll bars on if and only if arg is positive.
Horizontal scroll bars aren't implemented yet."
  (interactive "P")
  (error "Horizontal scroll bars aren't implemented yet"))
\f
;;;; Buffer navigation using the scroll bar.

;;; This was used for up-events on button 2, but no longer.
(defun scroll-bar-set-window-start (event)
  "Set the window start according to where the scroll bar is dragged.
EVENT should be a scroll bar click or drag event."
  (interactive "e")
  (let* ((end-position (event-end event))
	 (window (nth 0 end-position))
	 (portion-whole (nth 2 end-position)))
    (save-excursion
      (set-buffer (window-buffer window))
      (save-excursion
	(goto-char (+ (point-min)
		      (scroll-bar-scale portion-whole
					(- (point-max) (point-min)))))
	(beginning-of-line)
	(set-window-start window (point))))))

(defun scroll-bar-drag-position (portion-whole)
  "Calculate new window start for drag event."
  (save-excursion
    (goto-char (+ (point-min)
		  (scroll-bar-scale portion-whole
				    (- (point-max) (point-min)))))
    (beginning-of-line)
    (point)))

(defun scroll-bar-maybe-set-window-start (event)
  "Set the window start according to where the scroll bar is dragged.
Only change window start if the new start is substantially different.
EVENT should be a scroll bar click or drag event."
  (interactive "e")
  (let* ((end-position (event-end event))
	 (window (nth 0 end-position))
	 (portion-whole (nth 2 end-position))
	 (next-portion-whole (cons (1+ (car portion-whole))
				   (cdr portion-whole)))
	 portion-start
	 next-portion-start
	 (current-start (window-start window)))
    (save-excursion
      (set-buffer (window-buffer window))
      (setq portion-start (scroll-bar-drag-position portion-whole))
      (setq next-portion-start (max
				(scroll-bar-drag-position next-portion-whole)
				(1+ portion-start)))
      (if (or (>= current-start next-portion-start)
	      (< current-start portion-start))
	  (set-window-start window portion-start)
	;; Always set window start, to ensure scroll bar position is updated.
	(set-window-start window current-start)))))

;; Scroll the window to the proper position for EVENT.
(defun scroll-bar-drag-1 (event)
  (let* ((start-position (event-start event))
	 (window (nth 0 start-position))
	 (portion-whole (nth 2 start-position)))
    (save-excursion
      (set-buffer (window-buffer window))
      ;; Calculate position relative to the accessible part of the buffer.
      (goto-char (+ (point-min)
		    (scroll-bar-scale portion-whole
				      (- (point-max) (point-min)))))
      (vertical-motion 0 window)
      (set-window-start window (point)))))

(defun scroll-bar-drag (event)
  "Scroll the window by dragging the scroll bar slider.
If you click outside the slider, the window scrolls to bring the slider there."
  (interactive "e")
  (let* (done
	 (echo-keystrokes 0)
	 (end-position (event-end event))
	 (window (nth 0 end-position))
	 (before-scroll))
    (with-current-buffer (window-buffer window)
      (setq before-scroll point-before-scroll))
    (save-selected-window
      (select-window window)
      (setq before-scroll
	    (or before-scroll (point))))
    (scroll-bar-drag-1 event)
    (track-mouse
      (while (not done)
	(setq event (read-event))
	(if (eq (car-safe event) 'mouse-movement)
	    (setq event (read-event)))
	(cond ((eq (car-safe event) 'scroll-bar-movement)
	       (scroll-bar-drag-1 event))
	      (t
	       ;; Exit when we get the drag event; ignore that event.
	       (setq done t)))))
    (sit-for 0)
    (with-current-buffer (window-buffer window)
      (setq point-before-scroll before-scroll))))

(defun scroll-bar-scroll-down (event)
  "Scroll the window's top line down to the location of the scroll bar click.
EVENT should be a scroll bar click."
  (interactive "e")
  (let* ((end-position (event-end event))
	 (window (nth 0 end-position))
	 (before-scroll))
    (with-current-buffer (window-buffer window)
      (setq before-scroll point-before-scroll))
    (unwind-protect
	(save-selected-window
	  (let ((portion-whole (nth 2 end-position)))
	    (select-window window)
	    (setq before-scroll
		  (or before-scroll (point)))
	    (scroll-down
	     (scroll-bar-scale portion-whole (1- (window-height)))))
	  (sit-for 0))
      (with-current-buffer (window-buffer window)
	(setq point-before-scroll before-scroll)))))

(defun scroll-bar-scroll-up (event)
  "Scroll the line next to the scroll bar click to the top of the window.
EVENT should be a scroll bar click."
  (interactive "e")
  (let* ((end-position (event-end event))
	 (window (nth 0 end-position))
	 (before-scroll))
    (with-current-buffer (window-buffer window)
      (setq before-scroll point-before-scroll))
    (unwind-protect
	(save-selected-window
	  (let ((portion-whole (nth 2 end-position)))
	    (select-window window)
	    (setq before-scroll
		  (or before-scroll (point)))
	    (scroll-up
	     (scroll-bar-scale portion-whole (1- (window-height)))))
	  (sit-for 0))
      (with-current-buffer (window-buffer window)
	(setq point-before-scroll before-scroll)))))

\f
;;; Tookit scroll bars.

(defun scroll-bar-toolkit-scroll (event)
  (interactive "e")
  (let* ((end-position (event-end event))
	 (window (nth 0 end-position))
	 (part (nth 4 end-position))
	 before-scroll)
    (cond ((eq part 'end-scroll))
	  (t
	   (with-current-buffer (window-buffer window)
	     (setq before-scroll point-before-scroll))
	   (save-selected-window
	     (select-window window)
	     (setq before-scroll (or before-scroll (point)))
	     (cond ((eq part 'above-handle)
		    (scroll-up '-))
		   ((eq part 'below-handle)
		    (scroll-up nil))
		   ((eq part 'ratio)
		    (let* ((portion-whole (nth 2 end-position))
			   (lines (scroll-bar-scale portion-whole
						    (1- (window-height)))))
		      (scroll-up (cond ((not (zerop lines)) lines)
				       ((< (car portion-whole) 0) -1)
				       (t 1)))))
		   ((eq part 'up)
		    (scroll-up -1))
		   ((eq part 'down)
		    (scroll-up 1))
		   ((eq part 'top)
		    (set-window-start window (point-min)))
		   ((eq part 'bottom)
		    (goto-char (point-max))
		    (recenter))
		   ((eq part 'handle)
		    (scroll-bar-drag-1 event))))
	   (sit-for 0)
	   (with-current-buffer (window-buffer window)
	     (setq point-before-scroll before-scroll))))))


\f
;;;; Bindings.

;;; For now, we'll set things up to work like xterm.
(cond ((and (boundp 'x-toolkit-scroll-bars) x-toolkit-scroll-bars)
       (global-set-key [vertical-scroll-bar mouse-1]
		       'scroll-bar-toolkit-scroll))
      (t
       (global-set-key [vertical-scroll-bar mouse-1]
		       'scroll-bar-scroll-up)
       (global-set-key [vertical-scroll-bar drag-mouse-1]
		       'scroll-bar-scroll-up)
       (global-set-key [vertical-scroll-bar down-mouse-2]
		       'scroll-bar-drag)
       (global-set-key [vertical-scroll-bar mouse-3]
		       'scroll-bar-scroll-down)
       (global-set-key [vertical-scroll-bar drag-mouse-3]
		       'scroll-bar-scroll-down)))

\f
(provide 'scroll-bar)

;;; arch-tag: 6f1d01d0-0b1e-4bf8-86db-d491e0f399f3
;;; scroll-bar.el ends here
Commit	Line	Data
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:
d9ecc911 ER	32
dbc4e1c1 JB	33	(require 'mouse)
dbc4e1c1 JB	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.
6d62a90e JB	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)
1064fe38 RS	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))
19c6feac KH	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
6d62a90e JB	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)
cf4eb316 GM	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
6d62a90e JB	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