1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
|
;;; scrollbar.el -- window system-independent scrollbar support.
;;; Copyright (C) 1993 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, 675 Mass Ave, Cambridge, MA 02139, USA.
(require 'mouse)
;;;; Utilities.
(defun scrollbar-scale (num-denom whole)
"Given a pair (NUM . DENOM) and WHOLE, return (/ (* NUM WHOLE) DENOM).
This is handy for scaling a position on a scrollbar into real units,
like buffer positions. If SCROLLBAR-POS is the (PORTION . WHOLE) pair
from a scrollbar event, then (scrollbar-scale SCROLLBAR-POS
\(buffer-size)) is the position in the current buffer corresponding to
that scrollbar position."
;; We multiply before we divide to maintain precision.
;; We use floating point because the product of a large buffer size
;; with a large scrollbar portion can easily overflow a lisp int.
(truncate (/ (* (float (car num-denom)) whole) (cdr num-denom))))
;;;; Buffer navigation using the scrollbar.
(defun scrollbar-set-window-start (event)
"Set the window start according to where the scrollbar is dragged.
EVENT should be a scrollbar 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 (scrollbar-scale portion-whole (buffer-size)))
(beginning-of-line)
(set-window-start window (point))))))
(defun scrollbar-scroll-down (event)
"Scroll the window's top line down to the location of the scrollbar click.
EVENT should be a scrollbar click."
(interactive "e")
(let ((old-selected-window (selected-window)))
(unwind-protect
(progn
(let* ((end-position (event-end event))
(window (nth 0 end-position))
(portion-whole (nth 2 end-position)))
(select-window window)
(scroll-down
(scrollbar-scale portion-whole (1- (window-height))))))
(select-window old-selected-window))))
(defun scrollbar-scroll-up (event)
"Scroll the line next to the scrollbar click to the top of the window.
EVENT should be a scrollbar click."
(interactive "e")
(let ((old-selected-window (selected-window)))
(unwind-protect
(progn
(let* ((end-position (event-end event))
(window (nth 0 end-position))
(portion-whole (nth 2 end-position)))
(select-window window)
(scroll-up
(scrollbar-scale portion-whole (1- (window-height))))))
(select-window old-selected-window))))
;;;; Bindings.
;;; For now, we'll set things up to work like xterm.
(global-set-key [vertical-scrollbar mouse-1] 'scrollbar-scroll-up)
(global-set-key [vertical-scrollbar drag-mouse-1] 'scrollbar-scroll-up)
(global-set-key [vertical-scrollbar mouse-2] 'scrollbar-set-window-start)
(global-set-key [vertical-scrollbar drag-mouse-2] 'scrollbar-set-window-start)
(global-set-key [vertical-scrollbar mouse-3] 'scrollbar-scroll-down)
(global-set-key [vertical-scrollbar drag-mouse-3] 'scrollbar-scroll-down)
(provide 'scrollbar)
;;; scrollbar.el ends here
|
