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

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

;; Copyright (C) 1993-1995, 1999-2011 Free Software Foundation, Inc.

;; Maintainer: FSF
;; Keywords: hardware
;; Package: emacs

;; 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 3 of the License, 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.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

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

;;; Code:

(require 'mouse)
(eval-when-compile (require 'cl))

\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))))

(defun scroll-bar-columns (side)
  "Return the width, measured in columns, of the vertical scrollbar on SIDE.
SIDE must be the symbol `left' or `right'."
  (let* ((wsb   (window-scroll-bars))
         (vtype (nth 2 wsb))
         (cols  (nth 1 wsb)))
    (cond
     ((not (memq side '(left right)))
      (error "`left' or `right' expected instead of %S" side))
     ((and (eq vtype side) cols))
     ((eq (frame-parameter nil 'vertical-scroll-bars) side)
      ;; nil means it's a non-toolkit scroll bar, and its width in
      ;; columns is 14 pixels rounded up.
      (ceiling (or (frame-parameter nil 'scroll-bar-width) 14)
               (frame-char-width)))
     (0))))

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

(defvar scroll-bar-mode)
(defvar previous-scroll-bar-mode nil)

(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 (value)
  "Set the scroll bar mode to VALUE and put the new value into effect.
See the `scroll-bar-mode' variable for possible values to use."
  (if scroll-bar-mode
      (setq previous-scroll-bar-mode scroll-bar-mode))

  (setq scroll-bar-mode value)

  (when scroll-bar-mode-explicit
    (modify-all-frames-parameters (list (cons 'vertical-scroll-bars
					      scroll-bar-mode)))))

(defcustom scroll-bar-mode default-frame-scroll-bars
  "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 (lambda (_sym val) (set-scroll-bar-mode val)))

;; 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 get-scroll-bar-mode () scroll-bar-mode)
(defsetf get-scroll-bar-mode set-scroll-bar-mode)
(define-minor-mode scroll-bar-mode
  "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 positive
turn on scroll bars; otherwise turn off scroll bars."
  :variable (eq (get-scroll-bar-mode)
                (or previous-scroll-bar-mode
                    default-frame-scroll-bars)))

(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 default-frame-scroll-bars))))))

(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)))
    (with-current-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)))
    (with-current-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
      (with-current-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)

;;; scroll-bar.el ends here
Commit	Line	Data
55535639	1	;;; scroll-bar.el --- window system-independent scroll bar support
6d62a90e	2
73b0cd50	3	;; Copyright (C) 1993-1995, 1999-2011 Free Software Foundation, Inc.
6d62a90e JB	4
	5	;; Maintainer: FSF
	6	;; Keywords: hardware
bd78fa1d	7	;; Package: emacs
6d62a90e	8
b578f267	9	;; This file is part of GNU Emacs.
6d62a90e	10
eb3fa2cf	11	;; GNU Emacs is free software: you can redistribute it and/or modify
b578f267	12	;; it under the terms of the GNU General Public License as published by
eb3fa2cf GM	13	;; the Free Software Foundation, either version 3 of the License, or
eb3fa2cf GM	14	;; (at your option) 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	21	;; You should have received a copy of the GNU General Public License
eb3fa2cf	22	;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
76550a57	23
d9ecc911 ER	24	;;; Commentary:
	25
	26	;; Window-system-independent bindings of mouse clicks on the scroll bar.
	27	;; Presently emulates the scroll-bar behavior of xterm.
b578f267	28
d9ecc911 ER	29	;;; Code:
d9ecc911 ER	30
dbc4e1c1	31	(require 'mouse)
80ac5d4d	32	(eval-when-compile (require 'cl))
dbc4e1c1	33
6d62a90e JB	34	\f
	35	;;;; Utilities.
	36
86828678 RS	37	(defun scroll-bar-event-ratio (event)
	38	"Given a scroll bar event EVENT, return the scroll bar position as a ratio.
	39	The value is a cons cell (PORTION . WHOLE) containing two integers
	40	whose ratio gives the event's vertical position in the scroll bar, with 0
	41	referring to the top and 1 to the bottom."
	42	(nth 2 event))
	43
bf3c8a70	44	(defun scroll-bar-scale (num-denom whole)
6d62a90e	45	"Given a pair (NUM . DENOM) and WHOLE, return (/ (* NUM WHOLE) DENOM).
bf3c8a70 JB	46	This is handy for scaling a position on a scroll bar into real units,
	47	like buffer positions. If SCROLL-BAR-POS is the (PORTION . WHOLE) pair
	48	from a scroll bar event, then (scroll-bar-scale SCROLL-BAR-POS
6d62a90e	49	\(buffer-size)) is the position in the current buffer corresponding to
bf3c8a70	50	that scroll bar position."
6d62a90e JB	51	;; We multiply before we divide to maintain precision.
6d62a90e JB	52	;; We use floating point because the product of a large buffer size
bf3c8a70	53	;; with a large scroll bar portion can easily overflow a lisp int.
6d62a90e JB	54	(truncate (/ (* (float (car num-denom)) whole) (cdr num-denom))))
6d62a90e JB	55
9fd76d04 MY	56	(defun scroll-bar-columns (side)
	57	"Return the width, measured in columns, of the vertical scrollbar on SIDE.
	58	SIDE must be the symbol `left' or `right'."
	59	(let* ((wsb (window-scroll-bars))
	60	(vtype (nth 2 wsb))
	61	(cols (nth 1 wsb)))
	62	(cond
	63	((not (memq side '(left right)))
	64	(error "`left' or `right' expected instead of %S" side))
	65	((and (eq vtype side) cols))
	66	((eq (frame-parameter nil 'vertical-scroll-bars) side)
	67	;; nil means it's a non-toolkit scroll bar, and its width in
	68	;; columns is 14 pixels rounded up.
	69	(ceiling (or (frame-parameter nil 'scroll-bar-width) 14)
	70	(frame-char-width)))
	71	(0))))
	72
6d62a90e	73	\f
fe48f821	74	;;;; Helpful functions for enabling and disabling scroll bars.
fe48f821	75
1064fe38	76	(defvar scroll-bar-mode)
f62c3ee2	77	(defvar previous-scroll-bar-mode nil)
1064fe38	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	83	(defun set-scroll-bar-mode (value)
d7956b14 LMI	84	"Set the scroll bar mode to VALUE and put the new value into effect.
d7956b14 LMI	85	See the `scroll-bar-mode' variable for possible values to use."
f62c3ee2 JD	86	(if scroll-bar-mode
	87	(setq previous-scroll-bar-mode scroll-bar-mode))
	88
04c34f2e RS	89	(setq scroll-bar-mode value)
04c34f2e RS	90
2124851f	91	(when scroll-bar-mode-explicit
095fe281 KL	92	(modify-all-frames-parameters (list (cons 'vertical-scroll-bars
095fe281 KL	93	scroll-bar-mode)))))
04c34f2e	94
61f2fe7b	95	(defcustom scroll-bar-mode default-frame-scroll-bars
9201cc28	96	"Specify whether to have vertical scroll bars, and on which side.
04c34f2e RS	97	Possible values are nil (no scroll bars), `left' (scroll bars on left)
04c34f2e RS	98	and `right' (scroll bars on right).
463deb66 RS	99	To set this variable in a Lisp program, use `set-scroll-bar-mode'
	100	to make it take real effect.
	101	Setting the variable with a customization buffer also takes effect."
64453f32	102	:type '(choice (const :tag "none (nil)" nil)
04c34f2e RS	103	(const left)
	104	(const right))
	105	:group 'frames
2669fbfb RS	106	;; The default value for :initialize would try to use :set
	107	;; when processing the file in cus-dep.el.
	108	:initialize 'custom-initialize-default
06b60517	109	:set (lambda (_sym val) (set-scroll-bar-mode val)))
04c34f2e	110
2124851f RS	111	;; We just set scroll-bar-mode, but that was the default.
	112	;; If it is set again, that is for real.
	113	(setq scroll-bar-mode-explicit t)
	114
80ac5d4d SM	115	(defun get-scroll-bar-mode () scroll-bar-mode)
	116	(defsetf get-scroll-bar-mode set-scroll-bar-mode)
	117	(define-minor-mode scroll-bar-mode
04c34f2e	118	"Toggle display of vertical scroll bars on all frames.
fe48f821 JB	119	This command applies to all frames that exist and frames to be
fe48f821 JB	120	created in the future.
5f0e32ea JB	121	With a numeric argument, if the argument is positive
5f0e32ea JB	122	turn on scroll bars; otherwise turn off scroll bars."
80ac5d4d SM	123	:variable (eq (get-scroll-bar-mode)
	124	(or previous-scroll-bar-mode
	125	default-frame-scroll-bars)))
04c34f2e RS	126
	127	(defun toggle-scroll-bar (arg)
	128	"Toggle whether or not the selected frame has vertical scroll bars.
	129	With arg, turn vertical scroll bars on if and only if arg is positive.
	130	The variable `scroll-bar-mode' controls which side the scroll bars are on
	131	when they are turned on; if it is nil, they go on the left."
	132	(interactive "P")
	133	(if (null arg)
	134	(setq arg
	135	(if (cdr (assq 'vertical-scroll-bars
	136	(frame-parameters (selected-frame))))
19c6feac KH	137	-1 1))
19c6feac KH	138	(setq arg (prefix-numeric-value arg)))
1032e793 GV	139	(modify-frame-parameters
	140	(selected-frame)
	141	(list (cons 'vertical-scroll-bars
	142	(if (> arg 0)
61f2fe7b	143	(or scroll-bar-mode default-frame-scroll-bars))))))
04c34f2e	144
06b60517	145	(defun toggle-horizontal-scroll-bar (_arg)
04c34f2e RS	146	"Toggle whether or not the selected frame has horizontal scroll bars.
	147	With arg, turn horizontal scroll bars on if and only if arg is positive.
	148	Horizontal scroll bars aren't implemented yet."
	149	(interactive "P")
	150	(error "Horizontal scroll bars aren't implemented yet"))
fe48f821	151	\f
bf3c8a70	152	;;;; Buffer navigation using the scroll bar.
6d62a90e	153
7fdbcd83	154	;; This was used for up-events on button 2, but no longer.
bf3c8a70 JB	155	(defun scroll-bar-set-window-start (event)
	156	"Set the window start according to where the scroll bar is dragged.
	157	EVENT should be a scroll bar click or drag event."
6d62a90e	158	(interactive "e")
dbc4e1c1	159	(let* ((end-position (event-end event))
6d62a90e JB	160	(window (nth 0 end-position))
6d62a90e JB	161	(portion-whole (nth 2 end-position)))
7fdbcd83	162	(with-current-buffer (window-buffer window)
6d62a90e	163	(save-excursion
4cad38d5 JB	164	(goto-char (+ (point-min)
	165	(scroll-bar-scale portion-whole
	166	(- (point-max) (point-min)))))
6d62a90e JB	167	(beginning-of-line)
	168	(set-window-start window (point))))))
	169
aeee66be RS	170	(defun scroll-bar-drag-position (portion-whole)
	171	"Calculate new window start for drag event."
	172	(save-excursion
	173	(goto-char (+ (point-min)
	174	(scroll-bar-scale portion-whole
	175	(- (point-max) (point-min)))))
	176	(beginning-of-line)
	177	(point)))
	178
	179	(defun scroll-bar-maybe-set-window-start (event)
	180	"Set the window start according to where the scroll bar is dragged.
	181	Only change window start if the new start is substantially different.
	182	EVENT should be a scroll bar click or drag event."
	183	(interactive "e")
	184	(let* ((end-position (event-end event))
	185	(window (nth 0 end-position))
	186	(portion-whole (nth 2 end-position))
	187	(next-portion-whole (cons (1+ (car portion-whole))
	188	(cdr portion-whole)))
	189	portion-start
	190	next-portion-start
	191	(current-start (window-start window)))
7fdbcd83	192	(with-current-buffer (window-buffer window)
aeee66be RS	193	(setq portion-start (scroll-bar-drag-position portion-whole))
	194	(setq next-portion-start (max
	195	(scroll-bar-drag-position next-portion-whole)
	196	(1+ portion-start)))
15655694	197	(if (or (>= current-start next-portion-start)
aeee66be	198	(< current-start portion-start))
9c005c65 KH	199	(set-window-start window portion-start)
	200	;; Always set window start, to ensure scroll bar position is updated.
	201	(set-window-start window current-start)))))
aeee66be	202
e532b016 RS	203	;; Scroll the window to the proper position for EVENT.
	204	(defun scroll-bar-drag-1 (event)
	205	(let* ((start-position (event-start event))
	206	(window (nth 0 start-position))
	207	(portion-whole (nth 2 start-position)))
06b60517	208	(save-excursion
71572c03 JD	209	(with-current-buffer (window-buffer window)
	210	;; Calculate position relative to the accessible part of the buffer.
	211	(goto-char (+ (point-min)
	212	(scroll-bar-scale portion-whole
	213	(- (point-max) (point-min)))))
	214	(vertical-motion 0 window)
	215	(set-window-start window (point))))))
e532b016 RS	216
	217	(defun scroll-bar-drag (event)
	218	"Scroll the window by dragging the scroll bar slider.
	219	If you click outside the slider, the window scrolls to bring the slider there."
	220	(interactive "e")
c782bea5	221	(let* (done
cb183ca0 RS	222	(echo-keystrokes 0)
	223	(end-position (event-end event))
	224	(window (nth 0 end-position))
	225	(before-scroll))
	226	(with-current-buffer (window-buffer window)
	227	(setq before-scroll point-before-scroll))
	228	(save-selected-window
	229	(select-window window)
	230	(setq before-scroll
	231	(or before-scroll (point))))
	232	(scroll-bar-drag-1 event)
	233	(track-mouse
	234	(while (not done)
	235	(setq event (read-event))
	236	(if (eq (car-safe event) 'mouse-movement)
	237	(setq event (read-event)))
	238	(cond ((eq (car-safe event) 'scroll-bar-movement)
	239	(scroll-bar-drag-1 event))
	240	(t
	241	;; Exit when we get the drag event; ignore that event.
	242	(setq done t)))))
	243	(sit-for 0)
	244	(with-current-buffer (window-buffer window)
	245	(setq point-before-scroll before-scroll))))
e532b016	246
bf3c8a70 JB	247	(defun scroll-bar-scroll-down (event)
	248	"Scroll the window's top line down to the location of the scroll bar click.
	249	EVENT should be a scroll bar click."
6d62a90e	250	(interactive "e")
cb183ca0 RS	251	(let* ((end-position (event-end event))
	252	(window (nth 0 end-position))
	253	(before-scroll))
	254	(with-current-buffer (window-buffer window)
	255	(setq before-scroll point-before-scroll))
def7db1d KH	256	(unwind-protect
	257	(save-selected-window
	258	(let ((portion-whole (nth 2 end-position)))
	259	(select-window window)
	260	(setq before-scroll
	261	(or before-scroll (point)))
	262	(scroll-down
	263	(scroll-bar-scale portion-whole (1- (window-height)))))
	264	(sit-for 0))
	265	(with-current-buffer (window-buffer window)
	266	(setq point-before-scroll before-scroll)))))
6d62a90e	267
bf3c8a70 JB	268	(defun scroll-bar-scroll-up (event)
	269	"Scroll the line next to the scroll bar click to the top of the window.
	270	EVENT should be a scroll bar click."
6d62a90e	271	(interactive "e")
cb183ca0 RS	272	(let* ((end-position (event-end event))
	273	(window (nth 0 end-position))
	274	(before-scroll))
	275	(with-current-buffer (window-buffer window)
	276	(setq before-scroll point-before-scroll))
def7db1d KH	277	(unwind-protect
	278	(save-selected-window
	279	(let ((portion-whole (nth 2 end-position)))
	280	(select-window window)
	281	(setq before-scroll
	282	(or before-scroll (point)))
	283	(scroll-up
	284	(scroll-bar-scale portion-whole (1- (window-height)))))
	285	(sit-for 0))
	286	(with-current-buffer (window-buffer window)
	287	(setq point-before-scroll before-scroll)))))
6d62a90e JB	288
6d62a90e JB	289	\f
cf4eb316	290	;;; Tookit scroll bars.
6d62a90e	291
cf4eb316 GM	292	(defun scroll-bar-toolkit-scroll (event)
	293	(interactive "e")
	294	(let* ((end-position (event-end event))
	295	(window (nth 0 end-position))
	296	(part (nth 4 end-position))
	297	before-scroll)
2088cd64	298	(cond ((eq part 'end-scroll))
cf4eb316 GM	299	(t
	300	(with-current-buffer (window-buffer window)
	301	(setq before-scroll point-before-scroll))
	302	(save-selected-window
	303	(select-window window)
	304	(setq before-scroll (or before-scroll (point)))
	305	(cond ((eq part 'above-handle)
	306	(scroll-up '-))
	307	((eq part 'below-handle)
	308	(scroll-up nil))
d294c01f SM	309	((eq part 'ratio)
	310	(let* ((portion-whole (nth 2 end-position))
	311	(lines (scroll-bar-scale portion-whole
	312	(1- (window-height)))))
	313	(scroll-up (cond ((not (zerop lines)) lines)
	314	((< (car portion-whole) 0) -1)
	315	(t 1)))))
cf4eb316 GM	316	((eq part 'up)
	317	(scroll-up -1))
	318	((eq part 'down)
	319	(scroll-up 1))
	320	((eq part 'top)
	321	(set-window-start window (point-min)))
	322	((eq part 'bottom)
	323	(goto-char (point-max))
	324	(recenter))
	325	((eq part 'handle)
	326	(scroll-bar-drag-1 event))))
	327	(sit-for 0)
cf4eb316 GM	328	(with-current-buffer (window-buffer window)
cf4eb316 GM	329	(setq point-before-scroll before-scroll))))))
e532b016	330
cf4eb316 GM	331
	332	\f
	333	;;;; Bindings.
	334
7fdbcd83	335	;; For now, we'll set things up to work like xterm.
d08947c5	336	(cond ((and (boundp 'x-toolkit-scroll-bars) x-toolkit-scroll-bars)
cf4eb316 GM	337	(global-set-key [vertical-scroll-bar mouse-1]
	338	'scroll-bar-toolkit-scroll))
	339	(t
	340	(global-set-key [vertical-scroll-bar mouse-1]
	341	'scroll-bar-scroll-up)
	342	(global-set-key [vertical-scroll-bar drag-mouse-1]
	343	'scroll-bar-scroll-up)
	344	(global-set-key [vertical-scroll-bar down-mouse-2]
	345	'scroll-bar-drag)
	346	(global-set-key [vertical-scroll-bar mouse-3]
	347	'scroll-bar-scroll-down)
	348	(global-set-key [vertical-scroll-bar drag-mouse-3]
	349	'scroll-bar-scroll-down)))
6d62a90e JB	350
6d62a90e JB	351	\f
dc14eed2	352	(provide 'scroll-bar)
6d62a90e	353
bf3c8a70	354	;;; scroll-bar.el ends here