Close bug#3992.

[gnu-emacs] / lisp / scroll-bar.el

diff --git a/lisp/scroll-bar.el b/lisp/scroll-bar.el
index 86f6ea07e4690d80047971e3059c8ae79b4b113d..3f763fc59dad2e2d12e2a66bbdbffdde5fc99044 100644 (file)
--- a/lisp/scroll-bar.el
+++ b/lisp/scroll-bar.el
@@ -1,32 +1,31 @@
-;;; scroll-bar.el --- window system-independent scroll bar support.
+;;; scroll-bar.el --- window system-independent scroll bar support

 
 

-;;; Copyright (C) 1993 Free Software Foundation, Inc.
+;; Copyright (C) 1993, 1994, 1995, 1999, 2000, 2001, 2002, 2003,
+;;   2004, 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.

 
 ;; Maintainer: FSF
 ;; Keywords: hardware
 
 
 ;; Maintainer: FSF
 ;; Keywords: hardware
 

-;;; This file is part of GNU 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 2, or (at your option)
-;;; any later version.
+;; 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.
+;; 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.
-
-;;; Code:
+;; 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.
 
 ;;; Commentary:
 
 ;; Window-system-independent bindings of mouse clicks on the scroll bar.
 ;; Presently emulates the scroll-bar behavior of xterm.

+

 ;;; Code:
 
 (require 'mouse)
 ;;; Code:
 
 (require 'mouse)


@@ -34,6 +33,13 @@
 \f
 ;;;; Utilities.
 
 \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,
 (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,


@@ -46,40 +52,111 @@ that scroll bar position."
   ;; with a large scroll bar portion can easily overflow a lisp int.
   (truncate (/ (* (float (car num-denom)) whole) (cdr num-denom))))
 
   ;; 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.
 \f
 ;;;; Helpful functions for enabling and disabling scroll bars.

-(defvar scroll-bar-mode nil)

 
 

-(defun scroll-bar-mode (flag)
-  "Toggle display of vertical scroll bars on each frame.
+(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-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."
+  (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 '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.
 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."
+With a numeric argument, if the argument is positive
+turn on scroll bars; otherwise turn off scroll bars."

   (interactive "P")
   (interactive "P")

-  (setq scroll-bar-mode (if (null flag) (not scroll-bar-mode)
-                         (or (not (numberp flag)) (>= flag 0))))
-  (mapcar
-   (function
-    (lambda (param-name)
-      (let ((parameter (assq param-name default-frame-alist)))
-       (if (consp parameter)
-           (setcdr parameter scroll-bar-mode)
-         (setq default-frame-alist
-               (cons (cons param-name scroll-bar-mode)
-                     default-frame-alist))))))
-   '(vertical-scroll-bars horizontal-scroll-bars))
-  (let ((frames (frame-list)))
-    (while frames
-      (modify-frame-parameters
-       (car frames)
-       (list (cons 'vertical-scroll-bars scroll-bar-mode)
-            (cons 'horizontal-scroll-bars scroll-bar-mode)))
-      (setq frames (cdr frames)))))
+
+  ;; Tweedle the variable according to the argument.
+  (set-scroll-bar-mode (if (if (null flag)
+                              (not scroll-bar-mode)
+                            (setq flag (prefix-numeric-value flag))
+                            (or (not (numberp flag)) (> flag 0)))
+                          (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.
 
 \f
 ;;;; Buffer navigation using the scroll bar.
 

-;;; This was used for up-events on button 2, but no longer.
+;; 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."
 (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."


@@ -87,29 +164,76 @@ EVENT should be a scroll bar click or drag event."
   (let* ((end-position (event-end event))
         (window (nth 0 end-position))
         (portion-whole (nth 2 end-position)))
   (let* ((end-position (event-end event))
         (window (nth 0 end-position))
         (portion-whole (nth 2 end-position)))

-    (save-excursion
-      (set-buffer (window-buffer window))
+    (with-current-buffer (window-buffer window)

       (save-excursion
       (save-excursion

-       (goto-char (scroll-bar-scale portion-whole (buffer-size)))
+       (goto-char (+ (point-min)
+                     (scroll-bar-scale portion-whole
+                                       (- (point-max) (point-min)))))

        (beginning-of-line)
        (set-window-start window (point))))))
 
        (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)))
 ;; 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))
-      (goto-char (scroll-bar-scale portion-whole (buffer-size)))
-      (beginning-of-line)
-      (set-window-start window (point)))))
+    (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")
 
 (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)
+  (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)
     (scroll-bar-drag-1 event)
     (track-mouse
       (while (not done)


@@ -120,51 +244,117 @@ If you click outside the slider, the window scrolls to bring the slider there."
               (scroll-bar-drag-1 event))
              (t
               ;; Exit when we get the drag event; ignore that event.
               (scroll-bar-drag-1 event))
              (t
               ;; Exit when we get the drag event; ignore that event.

-              (setq done t)))))))
+              (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")
 
 (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 ((old-selected-window (selected-window)))
+  (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
     (unwind-protect

-       (progn
-         (let* ((end-position (event-end event))
-                (window (nth 0 end-position))
-                (portion-whole (nth 2 end-position)))
+       (save-selected-window
+         (let ((portion-whole (nth 2 end-position)))

            (select-window window)
            (select-window window)

+           (setq before-scroll
+                 (or before-scroll (point)))

            (scroll-down
            (scroll-down

-            (scroll-bar-scale portion-whole (1- (window-height))))))
-      (select-window old-selected-window))))
+            (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")
 
 (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 ((old-selected-window (selected-window)))
+  (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
     (unwind-protect

-       (progn
-         (let* ((end-position (event-end event))
-                (window (nth 0 end-position))
-                (portion-whole (nth 2 end-position)))
+       (save-selected-window
+         (let ((portion-whole (nth 2 end-position)))

            (select-window window)
            (select-window window)

+           (setq before-scroll
+                 (or before-scroll (point)))

            (scroll-up
            (scroll-up

-            (scroll-bar-scale portion-whole (1- (window-height))))))
-      (select-window old-selected-window))))
+            (scroll-bar-scale portion-whole (1- (window-height)))))
+         (sit-for 0))
+      (with-current-buffer (window-buffer window)
+       (setq point-before-scroll before-scroll)))))

 
 \f
 
 \f

-;;;; Bindings.
+;;; 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))))))

 
 

-;;; For now, we'll set things up to work like xterm.
-(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)
+\f
+;;;; Bindings.

 
 

-(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)
+;; 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)
 
 
 \f
 (provide 'scroll-bar)
 

+;; arch-tag: 6f1d01d0-0b1e-4bf8-86db-d491e0f399f3

 ;;; scroll-bar.el ends here
 ;;; scroll-bar.el ends here