X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/6538766ad9352d1410a0196e5e041c8d81d07e75..3db571c0d71c8d568ff54786606cccad2b138ddc:/lisp/scroll-bar.el

diff --git a/lisp/scroll-bar.el b/lisp/scroll-bar.el
index ca7d14532e..1fabb78dc4 100644
--- a/lisp/scroll-bar.el
+++ b/lisp/scroll-bar.el
@@ -1,32 +1,33 @@
-;;; scroll-bar.el --- window system-independent scroll bar support.
+;;; scroll-bar.el --- window system-independent scroll bar support
 
-;;; Copyright (C) 1993, 1994, 1995 Free Software Foundation, Inc.
+;; Copyright (C) 1993, 1994, 1995, 1999, 2000, 2001, 2002, 2003,
+;;   2004, 2005 Free Software Foundation, Inc.
 
 ;; 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 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.
+;; 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; see the file COPYING.  If not, write to the
+;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+;; Boston, MA 02110-1301, USA.
 
 ;;; Commentary:
 
 ;; Window-system-independent bindings of mouse clicks on the scroll bar.
 ;; Presently emulates the scroll-bar behavior of xterm.
+
 ;;; Code:
 
 (require 'mouse)
@@ -53,47 +54,115 @@ 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))))
 
+(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))))
+
 
 ;;;; Helpful functions for enabling and disabling scroll bars.
 
-(defun scroll-bar-mode (flag)
-  "Toggle display of vertical scroll bars on each frame.
-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)))
+(defvar scroll-bar-mode)
 
-  ;; Obtain the current setting by looking at default-frame-alist.
-  (let ((scroll-bar-mode
-	 (let ((assq (assq 'vertical-scroll-bars default-frame-alist)))
-	   (if assq (cdr assq) t))))
+(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.")
 
-    ;; Tweedle it according to the argument.
-    (setq scroll-bar-mode (if (null flag) (not scroll-bar-mode)
-			    (or (not (numberp flag)) (>= flag 0))))
+(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.
-    (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 ((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)
-	       (cons 'horizontal-scroll-bars scroll-bar-mode)))
+	 (list (cons 'vertical-scroll-bars scroll-bar-mode)))
 	(setq frames (cdr frames))))))
+
+(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.
+With a numeric argument, if the argument is negative,
+turn off scroll bars; otherwise, turn on scroll bars."
+  (interactive "P")
+
+  ;; 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)))
+			   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"))
 
 ;;;; Buffer navigation using the scroll bar.
 
@@ -114,6 +183,40 @@ EVENT should be a scroll bar click or drag event."
 	(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))
@@ -125,7 +228,7 @@ EVENT should be a scroll bar click or drag event."
       (goto-char (+ (point-min)
 		    (scroll-bar-scale portion-whole
 				      (- (point-max) (point-min)))))
-      (beginning-of-line)
+      (vertical-motion 0 window)
       (set-window-start window (point)))))
 
 (defun scroll-bar-drag (event)
@@ -133,75 +236,137 @@ EVENT should be a scroll bar click or drag event."
 If you click outside the slider, the window scrolls to bring the slider there."
   (interactive "e")
   (let* (done
-	 (echo-keystrokes 0))
-    (or point-before-scroll
-	(setq point-before-scroll (point)))
-    ;; Our scrolling can move point; don't let that clear point-before-scroll.
-    (let (point-before-scroll)
-      (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))))
+	 (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 ((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
-	(progn
-	  (let* ((end-position (event-end event))
-		 (window (nth 0 end-position))
-		 (portion-whole (nth 2 end-position)))
-	    (let (point-before-scroll)
-	      (select-window window))
-	    (or point-before-scroll
-		(setq point-before-scroll (point)))
-	    (let (point-before-scroll)
-	      (scroll-down
-	       (scroll-bar-scale portion-whole (1- (window-height)))))))
-      (select-window old-selected-window))))
+	(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 ((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
-	(progn
-	  (let* ((end-position (event-end event))
-		 (window (nth 0 end-position))
-		 (portion-whole (nth 2 end-position)))
-	    (let (point-before-scroll)
-	      (select-window window))
-	    (or point-before-scroll
-		(setq point-before-scroll (point)))
-	    (let (point-before-scroll)
-	      (scroll-up
-	       (scroll-bar-scale portion-whole (1- (window-height)))))))
-      (select-window old-selected-window))))
+	(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)))))
 
 
-;;;; Bindings.
+;;; Tookit scroll bars.
 
-;;; 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)
+(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))))))
 
-(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)
+
+;;;; 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)))
 
 
 (provide 'scroll-bar)
 
+;;; arch-tag: 6f1d01d0-0b1e-4bf8-86db-d491e0f399f3
 ;;; scroll-bar.el ends here