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

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

;; Copyright (C) 1993, 1994, 1995, 1999, 2000, 2001
;;  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
  (if (eq system-type 'windows-nt) 'right '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)")
		 (const left)
		 (const right))
  :group 'frames
  :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))
			      (if (eq system-type 'windows-nt) 'right '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
		       (if (eq system-type 'windows-nt) 'right '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)))))
      (beginning-of-line)
      (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)

;;; scroll-bar.el ends here
Commit	Line	Data
55535639	1	;;; scroll-bar.el --- window system-independent scroll bar support
6d62a90e	2
d08947c5 GM	3	;; Copyright (C) 1993, 1994, 1995, 1999, 2000, 2001
d08947c5 GM	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 GV	90	(defcustom scroll-bar-mode
1032e793 GV	91	(if (eq system-type 'windows-nt) 'right 'left)
04c34f2e RS	92	"*Specify whether to have vertical scroll bars, and on which side.
	93	Possible values are nil (no scroll bars), `left' (scroll bars on left)
	94	and `right' (scroll bars on right).
463deb66 RS	95	To set this variable in a Lisp program, use `set-scroll-bar-mode'
	96	to make it take real effect.
	97	Setting the variable with a customization buffer also takes effect."
04c34f2e RS	98	:type '(choice (const :tag "none (nil)")
	99	(const left)
	100	(const right))
	101	:group 'frames
e4b201bb	102	:set 'set-scroll-bar-mode-1)
04c34f2e	103
2124851f RS	104	;; We just set scroll-bar-mode, but that was the default.
	105	;; If it is set again, that is for real.
	106	(setq scroll-bar-mode-explicit t)
	107
b1ad7c13	108	(defun scroll-bar-mode (&optional flag)
04c34f2e	109	"Toggle display of vertical scroll bars on all frames.
fe48f821 JB	110	This command applies to all frames that exist and frames to be
	111	created in the future.
	112	With a numeric argument, if the argument is negative,
	113	turn off scroll bars; otherwise, turn on scroll bars."
	114	(interactive "P")
6ee9f953	115	(if flag (setq flag (prefix-numeric-value flag)))
ada464a7	116
04c34f2e	117	;; Tweedle the variable according to the argument.
e4b201bb	118	(set-scroll-bar-mode (if (null flag) (not scroll-bar-mode)
04c34f2e	119	(and (or (not (numberp flag)) (>= flag 0))
1032e793	120	(if (eq system-type 'windows-nt) 'right 'left)))))
04c34f2e RS	121
	122	(defun toggle-scroll-bar (arg)
	123	"Toggle whether or not the selected frame has vertical scroll bars.
	124	With arg, turn vertical scroll bars on if and only if arg is positive.
	125	The variable `scroll-bar-mode' controls which side the scroll bars are on
	126	when they are turned on; if it is nil, they go on the left."
	127	(interactive "P")
	128	(if (null arg)
	129	(setq arg
	130	(if (cdr (assq 'vertical-scroll-bars
	131	(frame-parameters (selected-frame))))
19c6feac KH	132	-1 1))
19c6feac KH	133	(setq arg (prefix-numeric-value arg)))
1032e793 GV	134	(modify-frame-parameters
	135	(selected-frame)
	136	(list (cons 'vertical-scroll-bars
	137	(if (> arg 0)
	138	(or scroll-bar-mode
	139	(if (eq system-type 'windows-nt) 'right 'left)))))))
04c34f2e RS	140
	141	(defun toggle-horizontal-scroll-bar (arg)
	142	"Toggle whether or not the selected frame has horizontal scroll bars.
	143	With arg, turn horizontal scroll bars on if and only if arg is positive.
	144	Horizontal scroll bars aren't implemented yet."
	145	(interactive "P")
	146	(error "Horizontal scroll bars aren't implemented yet"))
fe48f821	147	\f
bf3c8a70	148	;;;; Buffer navigation using the scroll bar.
6d62a90e	149
e532b016	150	;;; This was used for up-events on button 2, but no longer.
bf3c8a70 JB	151	(defun scroll-bar-set-window-start (event)
	152	"Set the window start according to where the scroll bar is dragged.
	153	EVENT should be a scroll bar click or drag event."
6d62a90e	154	(interactive "e")
dbc4e1c1	155	(let* ((end-position (event-end event))
6d62a90e JB	156	(window (nth 0 end-position))
	157	(portion-whole (nth 2 end-position)))
	158	(save-excursion
	159	(set-buffer (window-buffer window))
	160	(save-excursion
4cad38d5 JB	161	(goto-char (+ (point-min)
	162	(scroll-bar-scale portion-whole
	163	(- (point-max) (point-min)))))
6d62a90e JB	164	(beginning-of-line)
	165	(set-window-start window (point))))))
	166
aeee66be RS	167	(defun scroll-bar-drag-position (portion-whole)
	168	"Calculate new window start for drag event."
	169	(save-excursion
	170	(goto-char (+ (point-min)
	171	(scroll-bar-scale portion-whole
	172	(- (point-max) (point-min)))))
	173	(beginning-of-line)
	174	(point)))
	175
	176	(defun scroll-bar-maybe-set-window-start (event)
	177	"Set the window start according to where the scroll bar is dragged.
	178	Only change window start if the new start is substantially different.
	179	EVENT should be a scroll bar click or drag event."
	180	(interactive "e")
	181	(let* ((end-position (event-end event))
	182	(window (nth 0 end-position))
	183	(portion-whole (nth 2 end-position))
	184	(next-portion-whole (cons (1+ (car portion-whole))
	185	(cdr portion-whole)))
	186	portion-start
	187	next-portion-start
	188	(current-start (window-start window)))
	189	(save-excursion
	190	(set-buffer (window-buffer window))
	191	(setq portion-start (scroll-bar-drag-position portion-whole))
	192	(setq next-portion-start (max
	193	(scroll-bar-drag-position next-portion-whole)
	194	(1+ portion-start)))
15655694	195	(if (or (>= current-start next-portion-start)
aeee66be	196	(< current-start portion-start))
9c005c65 KH	197	(set-window-start window portion-start)
	198	;; Always set window start, to ensure scroll bar position is updated.
	199	(set-window-start window current-start)))))
aeee66be	200
e532b016 RS	201	;; Scroll the window to the proper position for EVENT.
	202	(defun scroll-bar-drag-1 (event)
	203	(let* ((start-position (event-start event))
	204	(window (nth 0 start-position))
	205	(portion-whole (nth 2 start-position)))
	206	(save-excursion
	207	(set-buffer (window-buffer window))
d2ae6f7e RS	208	;; Calculate position relative to the accessible part of the buffer.
	209	(goto-char (+ (point-min)
	210	(scroll-bar-scale portion-whole
	211	(- (point-max) (point-min)))))
e532b016 RS	212	(beginning-of-line)
	213	(set-window-start window (point)))))
	214
	215	(defun scroll-bar-drag (event)
	216	"Scroll the window by dragging the scroll bar slider.
	217	If you click outside the slider, the window scrolls to bring the slider there."
	218	(interactive "e")
c782bea5	219	(let* (done
cb183ca0 RS	220	(echo-keystrokes 0)
	221	(end-position (event-end event))
	222	(window (nth 0 end-position))
	223	(before-scroll))
	224	(with-current-buffer (window-buffer window)
	225	(setq before-scroll point-before-scroll))
	226	(save-selected-window
	227	(select-window window)
	228	(setq before-scroll
	229	(or before-scroll (point))))
	230	(scroll-bar-drag-1 event)
	231	(track-mouse
	232	(while (not done)
	233	(setq event (read-event))
	234	(if (eq (car-safe event) 'mouse-movement)
	235	(setq event (read-event)))
	236	(cond ((eq (car-safe event) 'scroll-bar-movement)
	237	(scroll-bar-drag-1 event))
	238	(t
	239	;; Exit when we get the drag event; ignore that event.
	240	(setq done t)))))
	241	(sit-for 0)
	242	(with-current-buffer (window-buffer window)
	243	(setq point-before-scroll before-scroll))))
e532b016	244
bf3c8a70 JB	245	(defun scroll-bar-scroll-down (event)
	246	"Scroll the window's top line down to the location of the scroll bar click.
	247	EVENT should be a scroll bar click."
6d62a90e	248	(interactive "e")
cb183ca0 RS	249	(let* ((end-position (event-end event))
	250	(window (nth 0 end-position))
	251	(before-scroll))
	252	(with-current-buffer (window-buffer window)
	253	(setq before-scroll point-before-scroll))
def7db1d KH	254	(unwind-protect
	255	(save-selected-window
	256	(let ((portion-whole (nth 2 end-position)))
	257	(select-window window)
	258	(setq before-scroll
	259	(or before-scroll (point)))
	260	(scroll-down
	261	(scroll-bar-scale portion-whole (1- (window-height)))))
	262	(sit-for 0))
	263	(with-current-buffer (window-buffer window)
	264	(setq point-before-scroll before-scroll)))))
6d62a90e	265
bf3c8a70 JB	266	(defun scroll-bar-scroll-up (event)
	267	"Scroll the line next to the scroll bar click to the top of the window.
	268	EVENT should be a scroll bar click."
6d62a90e	269	(interactive "e")
cb183ca0 RS	270	(let* ((end-position (event-end event))
	271	(window (nth 0 end-position))
	272	(before-scroll))
	273	(with-current-buffer (window-buffer window)
	274	(setq before-scroll point-before-scroll))
def7db1d KH	275	(unwind-protect
	276	(save-selected-window
	277	(let ((portion-whole (nth 2 end-position)))
	278	(select-window window)
	279	(setq before-scroll
	280	(or before-scroll (point)))
	281	(scroll-up
	282	(scroll-bar-scale portion-whole (1- (window-height)))))
	283	(sit-for 0))
	284	(with-current-buffer (window-buffer window)
	285	(setq point-before-scroll before-scroll)))))
6d62a90e JB	286
6d62a90e JB	287	\f
cf4eb316	288	;;; Tookit scroll bars.
6d62a90e	289
cf4eb316 GM	290	(defun scroll-bar-toolkit-scroll (event)
	291	(interactive "e")
	292	(let* ((end-position (event-end event))
	293	(window (nth 0 end-position))
	294	(part (nth 4 end-position))
	295	before-scroll)
2088cd64	296	(cond ((eq part 'end-scroll))
cf4eb316 GM	297	(t
	298	(with-current-buffer (window-buffer window)
	299	(setq before-scroll point-before-scroll))
	300	(save-selected-window
	301	(select-window window)
	302	(setq before-scroll (or before-scroll (point)))
	303	(cond ((eq part 'above-handle)
	304	(scroll-up '-))
	305	((eq part 'below-handle)
	306	(scroll-up nil))
d294c01f SM	307	((eq part 'ratio)
	308	(let* ((portion-whole (nth 2 end-position))
	309	(lines (scroll-bar-scale portion-whole
	310	(1- (window-height)))))
	311	(scroll-up (cond ((not (zerop lines)) lines)
	312	((< (car portion-whole) 0) -1)
	313	(t 1)))))
cf4eb316 GM	314	((eq part 'up)
	315	(scroll-up -1))
	316	((eq part 'down)
	317	(scroll-up 1))
	318	((eq part 'top)
	319	(set-window-start window (point-min)))
	320	((eq part 'bottom)
	321	(goto-char (point-max))
	322	(recenter))
	323	((eq part 'handle)
	324	(scroll-bar-drag-1 event))))
	325	(sit-for 0)
cf4eb316 GM	326	(with-current-buffer (window-buffer window)
cf4eb316 GM	327	(setq point-before-scroll before-scroll))))))
e532b016	328
cf4eb316 GM	329
	330	\f
	331	;;;; Bindings.
	332
	333	;;; For now, we'll set things up to work like xterm.
d08947c5	334	(cond ((and (boundp 'x-toolkit-scroll-bars) x-toolkit-scroll-bars)
cf4eb316 GM	335	(global-set-key [vertical-scroll-bar mouse-1]
	336	'scroll-bar-toolkit-scroll))
	337	(t
	338	(global-set-key [vertical-scroll-bar mouse-1]
	339	'scroll-bar-scroll-up)
	340	(global-set-key [vertical-scroll-bar drag-mouse-1]
	341	'scroll-bar-scroll-up)
	342	(global-set-key [vertical-scroll-bar down-mouse-2]
	343	'scroll-bar-drag)
	344	(global-set-key [vertical-scroll-bar mouse-3]
	345	'scroll-bar-scroll-down)
	346	(global-set-key [vertical-scroll-bar drag-mouse-3]
	347	'scroll-bar-scroll-down)))
6d62a90e JB	348
6d62a90e JB	349	\f
dc14eed2	350	(provide 'scroll-bar)
6d62a90e	351
bf3c8a70	352	;;; scroll-bar.el ends here