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+;;; ediff-wind.el --- window manipulation utilities
+;;; Copyright (C) 1994 Free Software Foundation, Inc.
+
+;; Author: Michael Kifer <kifer@cs.sunysb.edu>
+
+;; 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 'ediff-init)
+
+
+(defvar ediff-window-setup-function (if (not window-system)
+					'ediff-setup-windows-plain
+				      'ediff-setup-windows-multiframe)
+  "*Function called to set up windows.
+Ediff provides a choice of two functions: ediff-setup-windows-plain, for
+doing everything in one frame, and ediff-setup-windows-multiframe,
+which sets the control panel in a separate frame. Also, if the latter
+function detects that one of the buffers A/B is seen in some other frame,
+it will try to keep that buffer in that frame.
+
+If you don't like the two functions provided---write your own one.
+The basic guidelines:
+    1. It should leave the control buffer current and the control window
+       selected. 
+    2. It should set ediff-window-A, ediff-window-B, ediff-window-C,
+       and ediff-control-window to contain window objects that display
+       the corresponding buffers.
+    3. It should accept the following arguments:
+       buffer-A, buffer-B, buffer-C, control-buffer
+       Buffer C may not be used in jobs that compare only two buffers.
+If you plan to do something fancy, take a close look at how the two
+provided functions are written.")
+
+;; indicates if we are in a multiframe setup
+(ediff-defvar-local ediff-multiframe nil "")
+
+;; Share of the frame occupied by the merge window (buffer C)
+(ediff-defvar-local ediff-merge-window-share 0.45 "")
+
+;; The control window.
+(ediff-defvar-local ediff-control-window nil "")
+;; Official window for buffer A
+(ediff-defvar-local ediff-window-A nil "")
+;; Official window for buffer B
+(ediff-defvar-local ediff-window-B nil "")
+;; Official window for buffer C
+(ediff-defvar-local ediff-window-C nil "")
+;; Ediff's window configuration.
+;; Used to minimize the need to rearrange windows.
+(ediff-defvar-local ediff-window-config-saved "" "")
+
+
+(defvar ediff-split-window-function 'split-window-vertically
+  "*The function used to split the main window between buffer-A and buffer-B.
+You can set it to a horizontal split instead of the default vertical split
+by setting this variable to `split-window-horizontally'.
+You can also have your own function to do fancy splits.
+This variable has no effect when buffer-A/B are shown in different frames.
+In this case, Ediff will use those frames to display these buffers.")
+
+(defvar ediff-merge-split-window-function 'split-window-horizontally
+  "*The function used to split the main window between buffer-A and buffer-B.
+You can set it to a vertical split instead of the default horizontal split
+by setting this variable to `split-window-vertically'.
+You can also have your own function to do fancy splits.
+This variable has no effect when buffer-A/B/C are shown in different frames.
+In this case, Ediff will use those frames to display these buffers.")
+
+(defconst ediff-control-frame-parameters
+  (if window-system
+      (list 
+       '(name . "Ediff")
+       ;;'(unsplittable . t)
+       '(minibuffer . nil)
+       '(vertical-scroll-bars . nil)  ; FSF only
+       '(scrollbar-width . 0)         ; XEmacs only
+       '(menu-bar-lines . 0)          ; FSF only
+       ;; don't lower and auto-raise
+       '(auto-lower . nil)
+       '(auto-raise . t)
+       ;; this blocks queries from  window manager as to where to put
+       ;; ediff's control frame. we put the frame outside the display,
+       ;; so the initial frame won't jump all over the screen
+       (cons 'top  (if (fboundp 'x-display-pixel-height)
+		       (1+ (x-display-pixel-height))
+		     3000))
+       (cons 'left (if (fboundp 'x-display-pixel-width)
+		       (1+ (x-display-pixel-width))
+		     3000))
+       ))
+  "Frame parameters for displaying Ediff Control Panel.
+Do not specify width and height here. These are computed automatically.")
+
+(defvar ediff-control-frame-position-function 'ediff-make-frame-position
+  "Function to call to determine the desired location for the control panel.
+Expects three parameters: the control buffer, the desired width and height
+of the control frame. It returns an association list
+of the form \(\(top . <position>\) \(left . <position>\)\)")
+
+(defvar ediff-control-frame-upward-shift (if ediff-xemacs-p 36 4)
+  "*The upward shift of control frame from the top of buffer A's frame.
+Measured in pixels.
+This is used by the default control frame positioning function,
+`ediff-make-frame-position'. This variable is provided for easy
+customization of the default.")
+
+(defvar ediff-narrow-control-frame-leftward-shift (if ediff-xemacs-p 7 3)
+  "*The leftward shift of control frame from the right edge of buf A's frame.
+Measured in characters.
+This is used by the default control frame positioning function,
+`ediff-make-frame-position' to adjust the position of the control frame
+when it shows the short menu. This variable is provided for easy
+customization of the default.")
+
+(defvar ediff-wide-control-frame-rightward-shift 7
+  "*The rightward shift of control frame from the left edge of buf A's frame.
+Measured in characters.
+This is used by the default control frame positioning function,
+`ediff-make-frame-position' to adjust the position of the control frame
+when it shows the full menu. This variable is provided for easy
+customization of the default.")
+
+
+;; Wide frame display
+
+;; t means Ediff is using wide display
+(ediff-defvar-local ediff-wide-display-p nil "")
+;; keeps frame config for toggling wide display
+(ediff-defvar-local ediff-wide-display-orig-parameters nil 
+  "Frame parameters to be restored when the user wants to toggle the wide
+display off.")
+(ediff-defvar-local ediff-wide-display-frame nil
+  "Frame to be used for wide display.")
+(ediff-defvar-local ediff-make-wide-display-function 'ediff-make-wide-display
+  "The value is a function that is called to create a wide display.
+The function is called without arguments. It should resize the frame in
+which buffers A, B, and C are to be displayed, and it should save the old
+frame parameters in `ediff-wide-display-orig-parameters'.
+The variable `ediff-wide-display-frame' should be set to contain
+the frame used for the wide display.")
+
+;; Frame used for the control panel in a windowing system.
+(ediff-defvar-local ediff-control-frame nil "")
+
+(defvar ediff-prefer-iconified-control-frame nil
+  "*If t, keep control panel iconified when help message is off.
+This has effect only on a windowing system.
+If t, hiting `?' to toggle control panel off iconifies it.
+
+This is only useful in Emacs and only for certain kinds of window managers,
+such as TWM and its derivatives, since the window manager must permit
+keyboard input to go into icons. XEmacs completely ignores keyboard input
+into icons, regardless of the window manager.")
+
+;;; Functions
+
+(defun ediff-get-window-by-clicking (wind prev-wind wind-number)
+  (let (event)
+    (message
+     "Select windows by clicking. Please click on Window %d " wind-number)
+    (while (not (ediff-mouse-event-p (setq event (ediff-read-event))))
+      (if (sit-for 1) ; if sequence of events, wait till the final word
+	  (beep 1))
+      (message "Please click on Window %d " wind-number))
+    (ediff-read-event) ; discard event
+    (setq wind (if ediff-xemacs-p
+		   (event-window event)
+		 (posn-window (event-start event))))
+    ))
+      
+
+;; Select the lowest window on the frame.
+(defun ediff-select-lowest-window ()
+  (let* ((lowest-window (selected-window))
+	 (bottom-edge (car (cdr (cdr (cdr (window-edges))))))
+	 ;;(last-window (previous-window))
+         (last-window (save-excursion
+			(other-window -1) (selected-window)))
+         (window-search t))
+    (while window-search
+      (let* ((this-window (next-window))
+             (next-bottom-edge (car (cdr (cdr (cdr 
+                                               (window-edges this-window)))))))
+        (if (< bottom-edge next-bottom-edge)
+            (progn
+              (setq bottom-edge next-bottom-edge)
+              (setq lowest-window this-window)))
+
+        (select-window this-window)
+        (if (eq last-window this-window)
+            (progn
+              (select-window lowest-window)
+              (setq window-search nil)))))))
+
+ 
+
+;;; Common window setup routines
+
+;; Set up the window configuration.  If POS is given, set the points to
+;; the beginnings of the buffers.
+;; When 3way comparison is added, this will have to choose the appropriate
+;; setup function based on ediff-job-name
+(defun ediff-setup-windows (buffer-A buffer-B buffer-C control-buffer)
+  ;; Make sure we are not in the minibuffer window when we try to delete
+  ;; all other windows.
+  (run-hooks 'ediff-before-setup-windows-hooks)
+  (if (eq (selected-window) (minibuffer-window))
+      (other-window 1))
+      
+  ;; when support for buf C is added, the actual window setup function will
+  ;; depend on ediff-job-name
+  (or (ediff-keep-window-config control-buffer)
+      (funcall 
+       (ediff-eval-in-buffer control-buffer ediff-window-setup-function)
+       buffer-A buffer-B buffer-C control-buffer))
+  (run-hooks 'ediff-after-setup-windows-hooks))
+
+;; Just set up 3 windows.
+;; Usually used without windowing systems
+;; With windowing, we want to use dedicated frames.
+(defun ediff-setup-windows-plain (buffer-A buffer-B buffer-C control-buffer)
+  (ediff-eval-in-buffer control-buffer
+    (setq ediff-multiframe nil))
+  (if ediff-merge-job
+      (ediff-setup-windows-plain-merge
+       buffer-A buffer-B buffer-C control-buffer)
+    (ediff-setup-windows-plain-compare 
+     buffer-A buffer-B buffer-C control-buffer)))
+     
+(defun ediff-setup-windows-plain-merge (buf-A buf-B buf-C control-buffer)
+    ;; skip dedicated and unsplittable frames
+  (ediff-eval-in-buffer control-buffer
+    (if (and window-system (ediff-frame-live-p ediff-control-frame))
+	(progn
+	  (redraw-display)
+	  (ediff-delete-frame ediff-control-frame)
+	  (setq ediff-control-frame nil))))
+  (ediff-skip-unsuitable-frames)
+  (let ((window-min-height 1)
+	split-window-function 
+	merge-window-share merge-window-lines
+	wind-A wind-B wind-C)
+    (ediff-eval-in-buffer control-buffer
+      (setq merge-window-share ediff-merge-window-share
+	    ;; this lets us have local versions of ediff-split-window-function
+	    split-window-function ediff-split-window-function))
+    (delete-other-windows)
+    (split-window-vertically)
+    (ediff-select-lowest-window)
+    (ediff-setup-control-buffer control-buffer)
+    
+    ;; go to the upper window and split it betw A, B, and possibly C
+    (other-window 1) 
+    (setq merge-window-lines
+	  (max 2 (round (* (window-height) merge-window-share))))
+    (switch-to-buffer buf-A)
+    (setq wind-A (selected-window))
+    
+    ;; XEmacs seems to have a lot of trouble with display
+    ;; It won't set things right unless we tell it to sit still
+    (if ediff-xemacs-p (sit-for 0))
+    
+    (split-window-vertically (max 2 (- (window-height) merge-window-lines)))
+    (if (eq (selected-window) wind-A) 
+	(other-window 1))
+    (setq wind-C (selected-window))
+    (switch-to-buffer buf-C)
+    
+    (select-window wind-A)
+    (funcall split-window-function)
+		  
+    (if (eq (selected-window) wind-A)
+	(other-window 1))
+    (switch-to-buffer buf-B)
+    (setq wind-B (selected-window))
+	  
+    (ediff-eval-in-buffer control-buffer
+      (setq ediff-window-A wind-A
+	    ediff-window-B wind-B
+	    ediff-window-C wind-C))
+    
+    (ediff-select-lowest-window)
+    (ediff-setup-control-buffer control-buffer)
+    ))
+
+     
+;; This function handles all comparison jobs, including 3way jobs
+(defun ediff-setup-windows-plain-compare (buf-A buf-B buf-C control-buffer)
+  ;; skip dedicated and unsplittable frames
+  (ediff-eval-in-buffer control-buffer
+    (if (and window-system (ediff-frame-live-p ediff-control-frame))
+	(progn
+	  (redraw-display)
+	  (ediff-delete-frame ediff-control-frame)
+	  (setq ediff-control-frame nil))))
+  (ediff-skip-unsuitable-frames)
+  (let ((window-min-height 1)
+	split-window-function wind-width-or-height
+	three-way-comparison
+	job wind-A-start wind-B-start wind-A wind-B wind-C)
+    (ediff-eval-in-buffer control-buffer
+      (setq wind-A-start (ediff-overlay-start
+			  (ediff-get-value-according-to-buffer-type
+			   'A ediff-narrow-bounds))
+	    wind-B-start (ediff-overlay-start
+			  (ediff-get-value-according-to-buffer-type
+			   'B  ediff-narrow-bounds))
+	    job ediff-job-name
+	    ;; this lets us have local versions of ediff-split-window-function
+	    split-window-function ediff-split-window-function
+	    three-way-comparison ediff-3way-comparison-job))
+    (delete-other-windows)
+    (split-window-vertically)
+    (ediff-select-lowest-window)
+    (ediff-setup-control-buffer control-buffer)
+    
+    ;; go to the upper window and split it betw A, B, and possibly C
+    (other-window 1) 
+    (switch-to-buffer buf-A)
+    (setq wind-A (selected-window))
+    (if three-way-comparison
+	(setq wind-width-or-height
+	      (/ (if (eq split-window-function 'split-window-vertically)
+		     (window-height wind-A)
+		   (window-width wind-A))
+		 3)))
+    
+    ;; XEmacs seems to have a lot of trouble with display
+    ;; It won't set things right unless we tell it to sit still
+    (if ediff-xemacs-p (sit-for 0))
+    
+    (funcall split-window-function wind-width-or-height)
+		  
+    (if (eq (selected-window) wind-A)
+	(other-window 1))
+    (switch-to-buffer buf-B)
+    (setq wind-B (selected-window))
+	  
+    (if three-way-comparison
+	(progn
+	  (funcall split-window-function) ; equally
+	  (if (eq (selected-window) wind-B)
+	      (other-window 1))
+	  (switch-to-buffer buf-C)
+	  (setq wind-C (selected-window))))
+	  
+    (ediff-eval-in-buffer control-buffer
+      (setq ediff-window-A wind-A
+	    ediff-window-B wind-B
+	    ediff-window-C wind-C))
+    
+    ;; It is unlikely that we will want to implement 3way window comparison.
+    ;; So, only buffers A and B are used here.
+    (if (eq job 'ediff-windows)
+	(progn
+	  (set-window-start wind-A wind-A-start)
+	  (set-window-start wind-B wind-B-start)))
+  
+    (ediff-select-lowest-window)
+    (ediff-setup-control-buffer control-buffer)
+    ))
+
+    
+;; dispatch the appropriate window setup function
+(defun ediff-setup-windows-multiframe (buf-A buf-B buf-C control-buf)
+  (ediff-eval-in-buffer control-buf
+    (setq ediff-multiframe t))
+  (if ediff-merge-job
+      (ediff-setup-windows-multiframe-merge buf-A buf-B buf-C control-buf)
+    (ediff-setup-windows-multiframe-compare buf-A buf-B buf-C control-buf)))
+    
+(defun ediff-setup-windows-multiframe-merge (buf-A buf-B buf-C control-buf)
+;;; Algorithm:
+;;;   If A and B are in the same frame but C's frame is different--- use one
+;;;   frame for A and B and use a separate frame for C. 
+;;;   If C's frame is non-existent, then: if the first suitable
+;;;   non-dedicated frame  is different from A&B's, then use it for C.
+;;;   Otherwise, put A,B, and C in one frame.
+;;;   If buffers A, B, C are is separate frames, use them to display these
+;;;   buffers.
+
+  ;;   Skip dedicated or iconified frames.  Unsplittable frames are taken
+  ;;   care of later.
+  (ediff-skip-unsuitable-frames 'ok-unsplittable)
+  
+  (let* ((window-min-height 1)
+	 (wind-A (ediff-get-visible-buffer-window buf-A))
+	 (wind-B (ediff-get-visible-buffer-window buf-B))
+	 (wind-C (ediff-get-visible-buffer-window buf-C))
+	 (frame-A (if wind-A (ediff-window-frame wind-A)))
+	 (frame-B (if wind-B (ediff-window-frame wind-B)))
+	 (frame-C (if wind-C (ediff-window-frame wind-C)))
+	 ;; on wide display, do things in one frame
+	 (force-one-frame 
+	  (ediff-eval-in-buffer control-buf ediff-wide-display-p))
+	 ;; this lets us have local versions of ediff-split-window-function
+	 (split-window-function 
+	  (ediff-eval-in-buffer control-buf ediff-split-window-function))
+	 (orig-wind (selected-window))
+	 (orig-frame (ediff-selected-frame))
+	 (use-same-frame (or force-one-frame
+			     (eq frame-A (or frame-C orig-frame))
+			     (eq frame-B (or frame-C orig-frame))
+			     (not (ediff-frame-live-p frame-A))
+			     (not (ediff-frame-live-p frame-B))
+			     ))
+	 (use-same-frame-for-AB (and (not use-same-frame)
+				     (eq frame-A frame-B)))
+	 (merge-window-share (ediff-eval-in-buffer control-buf
+			       ediff-merge-window-share))
+	 merge-window-lines
+	 designated-minibuffer-frame
+	 done-A done-B done-C)
+    
+    ;; buf-A on its own
+    (if (and (window-live-p wind-A)
+	     (null use-same-frame)
+	     (null use-same-frame-for-AB))
+	(progn
+	  (select-window wind-A)
+	  (delete-other-windows)
+	  (switch-to-buffer buf-A)
+	  (setq wind-A (selected-window))
+	  (setq done-A t)))
+    
+    ;; buf-B on its own
+    (if (and (window-live-p wind-B) (null use-same-frame)) ; buf B on its own
+	(progn
+	  (select-window wind-B)
+	  (delete-other-windows)
+	  (switch-to-buffer buf-B)
+	  (setq wind-B (selected-window))
+	  (setq done-B t)))
+	  
+    ;; buf-C on its own
+    (if (and (window-live-p wind-C) (null use-same-frame)) ; buf C on its own
+	(progn
+	  (select-window wind-C)
+	  (delete-other-windows)
+	  (switch-to-buffer buf-C)
+	  (setq wind-C (selected-window))
+	  (setq done-C t)))
+    
+    (if use-same-frame-for-AB
+	(progn 
+	  (ediff-select-frame frame-A)
+	  (switch-to-buffer buf-A)
+	  (delete-other-windows)
+	  (setq wind-A (selected-window))
+	  
+	  (funcall split-window-function)
+	  (if (eq (selected-window) wind-A) 
+	      (other-window 1))
+	  (switch-to-buffer buf-B)
+	  (setq wind-B (selected-window))
+	  
+	  (setq done-A t
+		done-B t)))
+    
+    (if use-same-frame
+	(let ((curr-frame (ediff-selected-frame))
+	      (window-min-height 1))
+	  ;; avoid dedicated and non-splittable windows
+	  (ediff-skip-unsuitable-frames)
+	  (or (eq curr-frame (ediff-selected-frame))
+	      (setq wind-A nil
+		    wind-B nil
+		    wind-C nil
+		    orig-wind (selected-window)))
+
+	  ;; set the right frame
+	  (cond (wind-A (select-window wind-A))
+		(wind-B (select-window wind-B))
+		(wind-C (select-window wind-C))
+		(t (select-window orig-wind)))
+	  (delete-other-windows)
+	  (setq merge-window-lines
+		(max 2 (round (* (window-height) merge-window-share))))
+	  (switch-to-buffer buf-A)
+	  (setq wind-A (selected-window))
+	  
+	  ;; XEmacs seems to have a lot of trouble with display
+	  ;; It won't set things right unless we tell it to catch breath
+	  (if ediff-xemacs-p (sit-for 0))
+	  
+	  (split-window-vertically
+	   (max 2 (- (window-height) merge-window-lines)))
+	  (if (eq (selected-window) wind-A) 
+	      (other-window 1))
+	  (setq wind-C (selected-window))
+	  (switch-to-buffer buf-C)
+	  
+	  (select-window wind-A)
+	  
+	  (funcall split-window-function)
+	  (if (eq (selected-window) wind-A) 
+	      (other-window 1))
+	  (switch-to-buffer buf-B)
+	  (setq wind-B (selected-window))
+	  
+	  (setq done-A t
+		done-B t
+		done-C t)
+	  ))
+    
+    (or done-A  ; Buf A to be set in its own frame
+	(progn  ; It was not set up yet as it wasn't visible
+	  (select-window orig-wind)
+	  (delete-other-windows)
+	  (switch-to-buffer buf-A)
+	  (setq wind-A (selected-window))
+	  ))
+    (or done-B  ; Buf B to be set in its own frame
+	(progn  ; It was not set up yet as it wasn't visible
+	  (select-window orig-wind)
+	  (delete-other-windows)
+	  (switch-to-buffer buf-B)
+	  (setq wind-B (selected-window))
+	  ))
+    
+    (or done-C  ; Buf C to be set in its own frame.
+	(progn  ; It was not set up yet as it wasn't visible
+	  (select-window orig-wind)
+	  (delete-other-windows)
+	  (switch-to-buffer buf-C)
+	  (setq wind-C (selected-window))
+	  ))
+    
+    (ediff-eval-in-buffer control-buf
+      (setq ediff-window-A wind-A
+	    ediff-window-B wind-B
+	    ediff-window-C wind-C)
+	    
+      (setq frame-A (ediff-window-frame ediff-window-A)
+	    designated-minibuffer-frame (ediff-window-frame
+					 (minibuffer-window frame-A)))
+      (if ediff-xemacs-p
+	  ()
+	(if (not (eq designated-minibuffer-frame default-minibuffer-frame))
+	    (progn
+	      (setq default-minibuffer-frame designated-minibuffer-frame)
+	      (if (ediff-frame-live-p ediff-control-frame)
+		  (ediff-delete-frame ediff-control-frame)))
+	  ))
+      )
+    
+    (ediff-setup-control-frame control-buf)
+    ))
+
+  
+;; Window setup for all comparison jobs, including 3way comparisons
+(defun ediff-setup-windows-multiframe-compare (buf-A buf-B buf-C control-buf)
+;;; Algorithm:
+;;;    If a buffer is seen in a frame, use that frame for that buffer.  
+;;;    If it is not seen, use the current frame.
+;;;    If both buffers are not seen, they share the current frame.  If one
+;;;    of the buffers is not seen, it is placed in the current frame (where
+;;;    ediff started). If that frame is displaying the other buffer, it is
+;;;    shared between the two buffers.
+;;;    However, if we decide to put both buffers in one frame
+;;;    and the selected frame isn't splittable, we create a new frame and
+;;;    put both buffers there, event if one of this buffers is visible in
+;;;    another frame.
+  
+  ;; Skip dedicated or iconified frames.
+  ;; Unsplittable frames are taken care of later.
+  (ediff-skip-unsuitable-frames 'ok-unsplittable)
+  
+  (let* ((window-min-height 1)
+	 (wind-A (ediff-get-visible-buffer-window buf-A))
+	 (wind-B (ediff-get-visible-buffer-window buf-B))
+	 (wind-C (ediff-get-visible-buffer-window buf-C))
+	 (frame-A (if wind-A (ediff-window-frame wind-A)))
+	 (frame-B (if wind-B (ediff-window-frame wind-B)))
+	 (frame-C (if wind-C (ediff-window-frame wind-C)))
+	 (ctl-frame-exists-p (ediff-eval-in-buffer control-buf
+			       (ediff-frame-live-p ediff-control-frame)))
+	 ;; on wide display, do things in one frame
+	 (force-one-frame 
+	  (ediff-eval-in-buffer control-buf ediff-wide-display-p))
+	 ;; this lets us have local versions of ediff-split-window-function
+	 (split-window-function 
+	  (ediff-eval-in-buffer control-buf ediff-split-window-function))
+	 (three-way-comparison
+	  (ediff-eval-in-buffer control-buf ediff-3way-comparison-job))
+	 (orig-wind (selected-window))
+	 (use-same-frame (or force-one-frame
+			     (eq frame-A frame-B)
+			     (if three-way-comparison
+				 (or (eq frame-A frame-C)
+				     (eq frame-B frame-C)
+				     (not (ediff-frame-live-p frame-A))
+				     (not (ediff-frame-live-p frame-B))
+				     (not (ediff-frame-live-p frame-C))))
+			     (and (not (ediff-frame-live-p frame-B))
+				  (or ctl-frame-exists-p
+				      (eq frame-A (ediff-selected-frame))))
+			     (and (not (ediff-frame-live-p frame-A))
+				  (or ctl-frame-exists-p
+				      (eq frame-B (ediff-selected-frame))))))
+	 wind-A-start wind-B-start job-name
+	 designated-minibuffer-frame
+	 done-A done-B done-C)
+    
+    (ediff-eval-in-buffer control-buf
+      (setq wind-A-start (ediff-overlay-start
+			  (ediff-get-value-according-to-buffer-type
+			   'A ediff-narrow-bounds))
+	    wind-B-start (ediff-overlay-start
+			  (ediff-get-value-according-to-buffer-type
+			   'B ediff-narrow-bounds))
+	    job-name ediff-job-name))
+    
+    (if (and (window-live-p wind-A) (null use-same-frame)) ; buf-A on its own
+	(progn
+	  (select-window wind-A)
+	  (delete-other-windows)
+	  (switch-to-buffer buf-A)
+	  (setq wind-A (selected-window))
+	  (setq done-A t)))
+    
+    (if (and (window-live-p wind-B) (null use-same-frame)) ; buf B on its own
+	(progn
+	  (select-window wind-B)
+	  (delete-other-windows)
+	  (switch-to-buffer buf-B)
+	  (setq wind-B (selected-window))
+	  (setq done-B t)))
+	  
+    (if (and (window-live-p wind-C) (null use-same-frame)) ; buf C on its own
+	(progn
+	  (select-window wind-C)
+	  (delete-other-windows)
+	  (switch-to-buffer buf-C)
+	  (setq wind-C (selected-window))
+	  (setq done-C t)))
+    
+    (if use-same-frame
+	(let ((curr-frame (ediff-selected-frame))
+	      ;; this affects 3way setups only
+	      wind-width-or-height)
+	  ;; avoid dedicated and non-splittable windows
+	  (ediff-skip-unsuitable-frames)
+	  (or (eq curr-frame (ediff-selected-frame))
+	      (setq wind-A nil
+		    wind-B nil
+		    wind-C nil
+		    orig-wind (selected-window)))
+
+	  ;; set the right frame
+	  (cond (wind-A (select-window wind-A))
+		(wind-B (select-window wind-B))
+		(wind-C (select-window wind-C))
+		(t (select-window orig-wind)))
+	  (delete-other-windows)
+	  (switch-to-buffer buf-A)
+	  (setq wind-A (selected-window))
+	  
+	  ;; XEmacs seems to have a lot of trouble with display
+	  ;; It won't set things right unless we tell it to catch breath
+	  (if ediff-xemacs-p (sit-for 0))
+	  
+	  (if three-way-comparison
+	      (setq wind-width-or-height
+		    (/
+		     (if (eq split-window-function 'split-window-vertically)
+			 (window-height wind-A)
+		       (window-width wind-A))
+		     3)))
+	  
+	  (funcall split-window-function wind-width-or-height)
+	  (if (eq (selected-window) wind-A) 
+	      (other-window 1))
+	  (switch-to-buffer buf-B)
+	  (setq wind-B (selected-window))
+	  
+	  (if three-way-comparison
+	      (progn
+		(funcall split-window-function) ; equally
+		(if (memq (selected-window) (list wind-A wind-B))
+		    (other-window 1))
+		(switch-to-buffer buf-C)
+		(setq wind-C (selected-window))))
+	  (setq done-A t
+		done-B t
+		done-C t)
+	  ))
+    
+    (or done-A  ; Buf A to be set in its own frame
+	(progn  ; It was not set up yet as it wasn't visible
+	  (select-window orig-wind)
+	  (delete-other-windows)
+	  (switch-to-buffer buf-A)
+	  (setq wind-A (selected-window))
+	  ))
+    (or done-B  ; Buf B to be set in its own frame
+	(progn  ; It was not set up yet as it wasn't visible
+	  (select-window orig-wind)
+	  (delete-other-windows)
+	  (switch-to-buffer buf-B)
+	  (setq wind-B (selected-window))
+	  ))
+    
+    (if three-way-comparison
+	(or done-C  ; Buf C to be set in its own frame
+	    (progn  ; It was not set up yet as it wasn't visible
+	      (select-window orig-wind)
+	      (delete-other-windows)
+	      (switch-to-buffer buf-C)
+	      (setq wind-C (selected-window))
+	      )))
+    
+    (ediff-eval-in-buffer control-buf
+      (setq ediff-window-A wind-A
+	    ediff-window-B wind-B
+	    ediff-window-C wind-C)
+	    
+      (setq frame-A (ediff-window-frame ediff-window-A)
+	    designated-minibuffer-frame (ediff-window-frame
+					 (minibuffer-window frame-A)))
+      (if ediff-xemacs-p
+	  ()
+	(if (not (eq designated-minibuffer-frame default-minibuffer-frame))
+	    (progn
+	      (setq default-minibuffer-frame designated-minibuffer-frame)
+	      (if (ediff-frame-live-p ediff-control-frame)
+		  (ediff-delete-frame ediff-control-frame)))
+	  ))
+      )
+    
+    ;; It is unlikely that we'll implement ediff-windows that would compare
+    ;; 3 windows at once. So, we don't use buffer C here.
+    (if (eq job-name 'ediff-windows)
+	(progn
+	  (set-window-start wind-A wind-A-start)
+	  (set-window-start wind-B wind-B-start)))
+    
+    (ediff-setup-control-frame control-buf)
+    ))
+
+;; skip unsplittable and dedicated windows
+;; create a new splittable frame if none is found
+(defun ediff-skip-unsuitable-frames (&optional ok-unsplittable)
+  (if window-system
+      (let (last-window)
+	(while (and (not (eq (selected-window) last-window))
+		    (or
+		     (window-dedicated-p (selected-window))
+		     (ediff-frame-iconified-p (ediff-selected-frame))
+		     (if ok-unsplittable
+			 nil
+		       (ediff-frame-unsplittable-p (ediff-selected-frame)))))
+	  ;; remember where started
+	  (or last-window (setq last-window (selected-window)))
+	  ;; try new window
+	  (other-window 1 t))
+	(if (eq (selected-window) last-window)
+	    ;; fed up, no appropriate frame
+	    (progn
+	      (redraw-display)
+	      (ediff-select-frame (ediff-make-frame '((unsplittable)))))))))
+
+;; Prepare or refresh control frame
+(defun ediff-setup-control-frame (ctl-buffer)
+  (let ((window-min-height 1)
+	ctl-frame-iconified-p dont-iconify-ctl-frame deiconify-ctl-frame
+	ctl-frame old-ctl-frame lines 
+	fheight fwidth adjusted-parameters) 
+	
+    (ediff-eval-in-buffer ctl-buffer
+      (run-hooks 'ediff-before-setup-control-frame-hooks))
+  
+    (setq old-ctl-frame (ediff-eval-in-buffer ctl-buffer ediff-control-frame))
+    (if (ediff-frame-live-p old-ctl-frame)
+	(setq ctl-frame old-ctl-frame)
+      (redraw-display)
+      ;; frame should be made while ctl-buff is current, so that
+      ;; the local default-minibuffer-frame will be consulted and
+      ;; that ediff-control-frame-parameters will have the right value.
+      (ediff-eval-in-buffer ctl-buffer
+	(setq ctl-frame (ediff-make-frame 
+			 ediff-control-frame-parameters)))
+      (ediff-eval-in-buffer ctl-buffer (setq ediff-control-frame ctl-frame)))
+    
+    (setq ctl-frame-iconified-p (ediff-frame-iconified-p ctl-frame))
+    (ediff-select-frame ctl-frame)
+    (if (window-dedicated-p (selected-window))
+	()
+      (delete-other-windows)
+      (switch-to-buffer ctl-buffer))
+      
+    ;; must be before ediff-setup-control-buffer
+    (if ediff-xemacs-p
+	;; just a precaution--we should be in ctl-buffer already
+	(ediff-eval-in-buffer ctl-buffer
+	  (make-local-variable 'screen-title-format)
+	  (make-local-variable 'screen-icon-title-format)))
+    
+    (ediff-setup-control-buffer ctl-buffer)
+    (setq dont-iconify-ctl-frame
+	  (not (string= ediff-help-message ediff-brief-help-message)))
+    (setq deiconify-ctl-frame 
+	  (and (eq this-command 'ediff-toggle-help)
+	       dont-iconify-ctl-frame))
+    
+    ;; 1 more line for the modeline
+    (setq lines (if ediff-xemacs-p
+		    (+ 2 (count-lines (point-min) (point-max)))
+		  (1+ (count-lines (point-min) (point-max))))
+	  fheight lines
+	  fwidth (+ (ediff-help-message-line-length) 2)
+	  adjusted-parameters (append (list
+				       (cons 'width fwidth)
+				       (cons 'height fheight))
+				      (funcall
+				       ediff-control-frame-position-function
+				       ctl-buffer fwidth fheight)))
+    
+    ;; In XEmacs, buffer menubar needs to be killed before frame parameters
+    ;; are changed XEmacs needs to redisplay, as it has trouble setting
+    ;; height correctly otherwise.
+    (if (and ediff-xemacs-p (ediff-frame-has-menubar))
+	(progn (set-buffer-menubar nil)(sit-for 0)))
+    
+    ;; Under OS/2 (emx) we have to call modify frame parameters twice, in
+    ;; order to make sure that at least once we do it for non-iconified
+    ;; frame. If appears that in the OS/2 port of Emacs, one can't modify
+    ;; frame parameters of iconified frames.
+    (if (eq system-type 'emx)
+	(ediff-modify-frame-parameters ctl-frame adjusted-parameters))
+      
+    (goto-char (point-min))
+    
+    (cond ((and ediff-prefer-iconified-control-frame
+		(not ctl-frame-iconified-p)
+		(not dont-iconify-ctl-frame))
+	   (ediff-iconify-frame ctl-frame))
+	  ((or deiconify-ctl-frame
+	       (not ctl-frame-iconified-p))
+	   (ediff-raise-frame ctl-frame)))
+    
+    ;; This works around a bug in 19.25 and earlier. There, if frame gets
+    ;; iconified, the current buffer changes to that of the frame that
+    ;; becomes exposed as a result of this iconification.
+    ;; So, we make sure the current buffer doesn't change.
+    (ediff-select-frame ctl-frame)
+    (ediff-refresh-control-frame)
+    
+    (ediff-modify-frame-parameters ctl-frame adjusted-parameters)
+    
+    (if ediff-xemacs-p
+	(set-window-buffer-dedicated (selected-window) ctl-buffer)
+      (set-window-dedicated-p (selected-window) t))
+      
+    (or ediff-xemacs-p (sit-for 0 200)) ; emacs has trouble here, needs time
+    (or (ediff-frame-iconified-p ctl-frame)
+	(set-mouse-position ctl-frame 1 0))
+    (if (ediff-check-version '< 19 11 'xemacs) (sit-for 0))
+    (or ediff-xemacs-p (unfocus-frame))
+	
+    (if ediff-xemacs-p
+	(ediff-eval-in-buffer ctl-buffer
+	  (make-local-variable 'select-screen-hook)
+	  (add-hook 'select-screen-hook 'ediff-xemacs-select-screen-hook)
+	  ))
+	
+    (ediff-eval-in-buffer ctl-buffer
+      (run-hooks 'ediff-after-setup-control-frame-hooks))
+  
+    ))	 
+    
+
+;; finds a good place to clip control frame
+(defun ediff-make-frame-position (ctl-buffer ctl-frame-width ctl-frame-height)
+  (ediff-eval-in-buffer ctl-buffer
+    (let* ((frame-A (ediff-window-frame ediff-window-A))
+	   (frame-A-parameters (ediff-frame-parameters frame-A))
+	   (frame-A-top (cdr (assoc 'top frame-A-parameters)))
+	   (frame-A-left (cdr (assoc 'left frame-A-parameters)))
+	   (frame-A-width (ediff-frame-width frame-A))
+	   (ctl-frame ediff-control-frame)
+	   horizontal-adjustment upward-adjustment
+	   ctl-frame-top) 
+      
+      ;; Multiple control frames are clipped based on the value of
+      ;; ediff-control-buffer-number. This is done in order not to obscure
+      ;; other active control panels.
+      (setq horizontal-adjustment (* 2 ediff-control-buffer-number)
+	    upward-adjustment (* -14 ediff-control-buffer-number))
+
+      (setq ctl-frame-top (- frame-A-top
+			     upward-adjustment
+			     ediff-control-frame-upward-shift))
+      (list
+       (cons 'top (if (> ctl-frame-top 0) ctl-frame-top 1))
+       (cons 'left (+ frame-A-left
+		      (if ediff-prefer-long-help-message
+			  (* (ediff-frame-char-width ctl-frame)
+			     (+ ediff-wide-control-frame-rightward-shift
+				horizontal-adjustment))
+			(- (* frame-A-width
+			      (ediff-frame-char-width frame-A))
+			   (* (ediff-frame-char-width ctl-frame)
+			      (+ ctl-frame-width
+				 ediff-narrow-control-frame-leftward-shift
+				 horizontal-adjustment))))))))))
+			       
+(defun ediff-xemacs-select-screen-hook ()
+  (if (equal (ediff-selected-frame) ediff-control-frame)
+      (ediff-raise-frame ediff-control-frame)))
+	
+(defun ediff-make-wide-display ()
+  "Construct an alist of parameters for the wide display.
+Saves the old frame parameters in `ediff-wide-display-orig-parameters'.
+The frame to be resized is kept in `ediff-wide-display-frame'.
+This function modifies only the left margin and the width of the display.
+It assumes that it is called from within the control buffer."
+  (if (not (fboundp 'x-display-pixel-width))
+      (error
+       "Can't determine display width. Please upgrade your version of Emacs"))
+  (let* ((frame-A (ediff-window-frame ediff-window-A))
+	 (frame-A-params (ediff-frame-parameters frame-A))
+	 (cw (ediff-frame-char-width frame-A))
+	 (wd (- (/ (x-display-pixel-width) cw) 5)))
+    (setq ediff-wide-display-orig-parameters 
+	  (list (cons 'left (max 0 (cdr (assoc 'left frame-A-params))))
+		(cons 'width (cdr (assoc 'width frame-A-params))))
+	  ediff-wide-display-frame frame-A)
+    (ediff-modify-frame-parameters frame-A (list (cons 'left cw)
+						 (cons 'width wd)))))
+  
+      
+
+;; Revise the mode line to display which difference we have selected
+;; Also resets modelines of buffers A/B, since they may be clobbered by
+;; anothe invocations of Ediff.
+(defun ediff-refresh-mode-lines ()
+  (let (buf-A-state-diff buf-B-state-diff buf-C-state-diff buf-C-state-merge)
+    
+    (if (ediff-valid-difference-p)
+	(setq
+	 buf-C-state-diff (ediff-get-state-of-diff ediff-current-difference 'C)
+	 buf-C-state-merge (ediff-get-state-of-merge ediff-current-difference)
+	 buf-A-state-diff (ediff-get-state-of-diff ediff-current-difference 'A)
+	 buf-B-state-diff (ediff-get-state-of-diff ediff-current-difference 'B)
+	 buf-A-state-diff (if buf-A-state-diff
+			      (format "[%s] " buf-A-state-diff)
+			    "")
+	 buf-B-state-diff (if buf-B-state-diff
+			      (format "[%s] " buf-B-state-diff)
+			    "")
+	 buf-C-state-diff (if (and (ediff-buffer-live-p ediff-buffer-C)
+				   (or buf-C-state-diff buf-C-state-merge))
+			      (format "[%s%s] "
+				      (or buf-C-state-diff "")
+				      (if buf-C-state-merge
+					  (concat " " buf-C-state-merge)
+					""))
+			    ""))
+      (setq buf-A-state-diff ""
+	    buf-B-state-diff ""
+	    buf-C-state-diff ""))
+    
+    ;; control buffer format
+    (setq mode-line-format
+	  (list (if (ediff-narrow-control-frame-p) "   " "-- ")
+		mode-line-buffer-identification
+		"               Howdy!"))
+    ;; control buffer id
+    (setq mode-line-buffer-identification 
+	  (if (ediff-narrow-control-frame-p)
+	      (ediff-make-narrow-control-buffer-id 'skip-name)
+	    (ediff-make-wide-control-buffer-id)))
+    ;; Force mode-line redisplay
+    (force-mode-line-update)
+    
+    (if (and window-system (ediff-frame-live-p ediff-control-frame))
+	(ediff-refresh-control-frame))
+    
+    (ediff-eval-in-buffer ediff-buffer-A
+      (setq ediff-diff-status buf-A-state-diff)
+      (ediff-strip-mode-line-format)
+      (setq mode-line-format
+	    (list " A: " 'ediff-diff-status mode-line-format))
+      (force-mode-line-update))
+    (ediff-eval-in-buffer ediff-buffer-B
+      (setq ediff-diff-status buf-B-state-diff)
+      (ediff-strip-mode-line-format)
+      (setq mode-line-format
+	    (list " B: " 'ediff-diff-status mode-line-format))
+      (force-mode-line-update))
+    (if ediff-3way-job
+	(ediff-eval-in-buffer ediff-buffer-C
+	  (setq ediff-diff-status buf-C-state-diff)
+	  (ediff-strip-mode-line-format)
+	  (setq mode-line-format
+		(list " C: " 'ediff-diff-status mode-line-format))
+	  (force-mode-line-update)))
+    ))
+    
+  
+(defun ediff-refresh-control-frame ()
+  (if ediff-xemacs-p
+      (progn
+	(setq screen-title-format (ediff-make-narrow-control-buffer-id)
+	      screen-icon-title-format (ediff-make-narrow-control-buffer-id))
+	;; this forces update of the screen title
+	(ediff-modify-frame-parameters ediff-control-frame '(())))
+    (ediff-modify-frame-parameters
+     ediff-control-frame
+     (list (cons 'name (ediff-make-narrow-control-buffer-id))))
+     ))
+   
+  
+(defun ediff-make-narrow-control-buffer-id (&optional skip-name)
+  (concat
+   (if skip-name
+       " "
+     (concat
+      (cdr (assoc 'name ediff-control-frame-parameters))
+      ediff-control-buffer-suffix))
+   (cond ((< ediff-current-difference 0) 
+	  (format " _/%d" ediff-number-of-differences))
+	 ((>= ediff-current-difference ediff-number-of-differences)
+	  (format " $/%d" ediff-number-of-differences))
+	 (t
+	  (format " %d/%d"
+		  (1+ ediff-current-difference)
+		  ediff-number-of-differences)))))
+		  
+(defun ediff-make-wide-control-buffer-id ()
+  (cond ((< ediff-current-difference 0)
+	 (list (format "%%b   At start of %d diffs"
+		       ediff-number-of-differences)))
+	((>= ediff-current-difference ediff-number-of-differences)
+	 (list (format "%%b   At end of %d diffs"
+		       ediff-number-of-differences)))
+	(t
+	 (list (format "%%b   diff %d of %d"
+		       (1+ ediff-current-difference)
+		       ediff-number-of-differences)))))
+
+
+
+;; If buff is not live, return nil
+(defun ediff-get-visible-buffer-window (buff)
+  (if (ediff-buffer-live-p buff)
+      (if ediff-xemacs-p
+	  (get-buffer-window buff t)
+	(get-buffer-window buff 'visible))))
+	
+;;; Functions to decide when to redraw windows
+
+  
+(defun ediff-keep-window-config (control-buf)
+  (and (eq control-buf (current-buffer))
+       (/= (buffer-size) 0)
+       (ediff-eval-in-buffer control-buf
+	 (let ((ctl-wind ediff-control-window)
+	       (A-wind ediff-window-A)
+	       (B-wind ediff-window-B)
+	       (C-wind ediff-window-C))
+	  
+	   (and
+	    (ediff-window-visible-p A-wind)
+	    (ediff-window-visible-p B-wind)
+	    ;; if buffer C is defined then take it into account
+	    (or (not ediff-3way-job)
+		(ediff-window-visible-p C-wind))
+	    (eq (window-buffer A-wind) ediff-buffer-A)
+	    (eq (window-buffer B-wind) ediff-buffer-B)
+	    (or (not ediff-3way-job)
+		(eq (window-buffer C-wind) ediff-buffer-C))
+	    (string= ediff-window-config-saved
+		     (format "%S%S%S%S%S"
+			     ctl-wind A-wind B-wind C-wind
+			     ediff-split-window-function)))))))
+
+
+(provide 'ediff-wind)
+
+
+;;; ediff-wind.el ends here