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;;; window.el --- GNU Emacs window commands aside from those written in C

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;; Copyright (C) 1985, 1989, 1992-1994, 2000-2011
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;;   Free Software Foundation, Inc.
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;; Maintainer: FSF
;; Keywords: internal
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;; Package: emacs
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;; 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 tree functions.

;;; Code:

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

(defmacro save-selected-window (&rest body)
  "Execute BODY, then select the previously selected window.
The value returned is the value of the last form in BODY.

This macro saves and restores the selected window, as well as the
selected window in each frame.  If the previously selected window
is no longer live, then whatever window is selected at the end of
BODY remains selected.  If the previously selected window of some
frame is no longer live at the end of BODY, that frame's selected
window is left alone.

This macro saves and restores the current buffer, since otherwise
its normal operation could make a different buffer current.  The
order of recently selected windows and the buffer list ordering
are not altered by this macro (unless they are altered in BODY)."
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  (declare (indent 0) (debug t))
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  `(let ((save-selected-window-window (selected-window))
	 ;; It is necessary to save all of these, because calling
	 ;; select-window changes frame-selected-window for whatever
	 ;; frame that window is in.
	 (save-selected-window-alist
	  (mapcar (lambda (frame) (cons frame (frame-selected-window frame)))
		  (frame-list))))
     (save-current-buffer
       (unwind-protect
	   (progn ,@body)
	 (dolist (elt save-selected-window-alist)
	   (and (frame-live-p (car elt))
		(window-live-p (cdr elt))
		(set-frame-selected-window (car elt) (cdr elt) 'norecord)))
	 (when (window-live-p save-selected-window-window)
	   (select-window save-selected-window-window 'norecord))))))

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;; The following two functions are like `window-next-sibling' and
;; `window-prev-sibling' but the WINDOW argument is _not_ optional (so
;; they don't substitute the selected window for nil), and they return
;; nil when WINDOW doesn't have a parent (like a frame's root window or
;; a minibuffer window).
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(defsubst window-right (window)
  "Return WINDOW's right sibling.
Return nil if WINDOW is the root window of its frame.  WINDOW can
be any window."
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  (and window (window-parent window) (window-next-sibling window)))
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(defsubst window-left (window)
  "Return WINDOW's left sibling.
Return nil if WINDOW is the root window of its frame.  WINDOW can
be any window."
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  (and window (window-parent window) (window-prev-sibling window)))
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(defsubst window-child (window)
  "Return WINDOW's first child window."
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  (or (window-top-child window) (window-left-child window)))
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(defun window-child-count (window)
  "Return number of WINDOW's child windows."
  (let ((count 0))
    (when (and (windowp window) (setq window (window-child window)))
      (while window
	(setq count (1+ count))
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	(setq window (window-next-sibling window))))
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    count))

(defun window-last-child (window)
  "Return last child window of WINDOW."
  (when (and (windowp window) (setq window (window-child window)))
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    (while (window-next-sibling window)
      (setq window (window-next-sibling window))))
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  window)

(defsubst window-any-p (object)
  "Return t if OBJECT denotes a live or internal window."
  (and (windowp object)
       (or (window-buffer object) (window-child object))
       t))

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(defsubst window-normalize-buffer (buffer-or-name)
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  "Return buffer specified by BUFFER-OR-NAME.
BUFFER-OR-NAME must be either a buffer or a string naming a live
buffer and defaults to the current buffer."
  (cond
   ((not buffer-or-name)
    (current-buffer))
   ((bufferp buffer-or-name)
    (if (buffer-live-p buffer-or-name)
	buffer-or-name
      (error "Buffer %s is not a live buffer" buffer-or-name)))
   ((get-buffer buffer-or-name))
   (t
    (error "No such buffer %s" buffer-or-name))))

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(defsubst window-normalize-frame (frame)
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  "Return frame specified by FRAME.
FRAME must be a live frame and defaults to the selected frame."
  (if frame
      (if (frame-live-p frame)
	  frame
	(error "%s is not a live frame" frame))
    (selected-frame)))

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(defsubst window-normalize-any-window (window)
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  "Return window specified by WINDOW.
WINDOW must be a window that has not been deleted and defaults to
the selected window."
  (if window
      (if (window-any-p window)
	  window
	(error "%s is not a window" window))
    (selected-window)))

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(defsubst window-normalize-live-window (window)
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  "Return live window specified by WINDOW.
WINDOW must be a live window and defaults to the selected one."
  (if window
      (if (and (windowp window) (window-buffer window))
	  window
	(error "%s is not a live window" window))
    (selected-window)))

(defvar ignore-window-parameters nil
  "If non-nil, standard functions ignore window parameters.
The functions currently affected by this are `split-window',
`delete-window', `delete-other-windows' and `other-window'.

An application may bind this to a non-nil value around calls to
these functions to inhibit processing of window parameters.")

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(defconst window-safe-min-height 1
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  "The absolute minimum number of lines of a window.
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Anything less might crash Emacs.")

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(defcustom window-min-height 4
  "The minimum number of lines of any window.
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The value has to accommodate a mode- or header-line if present.
A value less than `window-safe-min-height' is ignored.  The value
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of this variable is honored when windows are resized or split.

Applications should never rebind this variable.  To resize a
window to a height less than the one specified here, an
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application should instead call `window-resize' with a non-nil
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IGNORE argument.  In order to have `split-window' make a window
shorter, explictly specify the SIZE argument of that function."
  :type 'integer
  :version "24.1"
  :group 'windows)

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(defconst window-safe-min-width 2
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  "The absolute minimum number of columns of a window.
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Anything less might crash Emacs.")

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(defcustom window-min-width 10
  "The minimum number of columns of any window.
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The value has to accommodate margins, fringes, or scrollbars if
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present.  A value less than `window-safe-min-width' is ignored.
The value of this variable is honored when windows are resized or
split.

Applications should never rebind this variable.  To resize a
window to a width less than the one specified here, an
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application should instead call `window-resize' with a non-nil
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IGNORE argument.  In order to have `split-window' make a window
narrower, explictly specify the SIZE argument of that function."
  :type 'integer
  :version "24.1"
  :group 'windows)

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(defun window-iso-combination-p (&optional window horizontal)
  "If WINDOW is a vertical combination return WINDOW's first child.
WINDOW can be any window and defaults to the selected one.
Optional argument HORIZONTAL non-nil means return WINDOW's first
child if WINDOW is a horizontal combination."
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  (setq window (window-normalize-any-window window))
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  (if horizontal
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      (window-left-child window)
    (window-top-child window)))
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(defsubst window-iso-combined-p (&optional window horizontal)
  "Return non-nil if and only if WINDOW is vertically combined.
WINDOW can be any window and defaults to the selected one.
Optional argument HORIZONTAL non-nil means return non-nil if and
only if WINDOW is horizontally combined."
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  (setq window (window-normalize-any-window window))
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  (let ((parent (window-parent window)))
    (and parent (window-iso-combination-p parent horizontal))))

(defun window-iso-combinations (&optional window horizontal)
  "Return largest number of vertically arranged subwindows of WINDOW.
WINDOW can be any window and defaults to the selected one.
Optional argument HORIZONTAL non-nil means to return the largest
number of horizontally arranged subwindows of WINDOW."
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  (setq window (window-normalize-any-window window))
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  (cond
   ((window-live-p window)
    ;; If WINDOW is live, return 1.
    1)
   ((window-iso-combination-p window horizontal)
    ;; If WINDOW is iso-combined, return the sum of the values for all
    ;; subwindows of WINDOW.
    (let ((child (window-child window))
	  (count 0))
      (while child
	(setq count
	      (+ (window-iso-combinations child horizontal)
		 count))
	(setq child (window-right child)))
      count))
   (t
    ;; If WINDOW is not iso-combined, return the maximum value of any
    ;; subwindow of WINDOW.
    (let ((child (window-child window))
	  (count 1))
      (while child
	(setq count
	      (max (window-iso-combinations child horizontal)
		   count))
	(setq child (window-right child)))
      count))))

(defun walk-window-tree-1 (proc walk-window-tree-window any &optional sub-only)
  "Helper function for `walk-window-tree' and `walk-window-subtree'."
  (let (walk-window-tree-buffer)
    (while walk-window-tree-window
      (setq walk-window-tree-buffer
	    (window-buffer walk-window-tree-window))
      (when (or walk-window-tree-buffer any)
	(funcall proc walk-window-tree-window))
      (unless walk-window-tree-buffer
	(walk-window-tree-1
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	 proc (window-left-child walk-window-tree-window) any)
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	(walk-window-tree-1
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	 proc (window-top-child walk-window-tree-window) any))
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      (if sub-only
	  (setq walk-window-tree-window nil)
	(setq walk-window-tree-window
	      (window-right walk-window-tree-window))))))

(defun walk-window-tree (proc &optional frame any)
  "Run function PROC on each live window of FRAME.
PROC must be a function with one argument - a window.  FRAME must
be a live frame and defaults to the selected one.  ANY, if
non-nil means to run PROC on all live and internal windows of
FRAME.

This function performs a pre-order, depth-first traversal of the
window tree.  If PROC changes the window tree, the result is
unpredictable."
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  (let ((walk-window-tree-frame (window-normalize-frame frame)))
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    (walk-window-tree-1
     proc (frame-root-window walk-window-tree-frame) any)))

(defun walk-window-subtree (proc &optional window any)
  "Run function PROC on each live subwindow of WINDOW.
WINDOW defaults to the selected window.  PROC must be a function
with one argument - a window.  ANY, if non-nil means to run PROC
on all live and internal subwindows of WINDOW.

This function performs a pre-order, depth-first traversal of the
window tree rooted at WINDOW.  If PROC changes that window tree,
the result is unpredictable."
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  (setq window (window-normalize-any-window window))
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  (walk-window-tree-1 proc window any t))

(defun windows-with-parameter (parameter &optional value frame any values)
  "Return a list of all windows on FRAME with PARAMETER non-nil.
FRAME defaults to the selected frame.  Optional argument VALUE
non-nil means only return windows whose window-parameter value of
PARAMETER equals VALUE \(comparison is done using `equal').
Optional argument ANY non-nil means consider internal windows
too.  Optional argument VALUES non-nil means return a list of cons
cells whose car is the value of the parameter and whose cdr is
the window."
  (let (this-value windows)
    (walk-window-tree
     (lambda (window)
       (when (and (setq this-value (window-parameter window parameter))
		  (or (not value) (or (equal value this-value))))
	   (setq windows
		 (if values
		     (cons (cons this-value window) windows)
		   (cons window windows)))))
     frame any)

    (nreverse windows)))

(defun window-with-parameter (parameter &optional value frame any)
  "Return first window on FRAME with PARAMETER non-nil.
FRAME defaults to the selected frame.  Optional argument VALUE
non-nil means only return a window whose window-parameter value
for PARAMETER equals VALUE \(comparison is done with `equal').
Optional argument ANY non-nil means consider internal windows
too."
  (let (this-value windows)
    (catch 'found
      (walk-window-tree
       (lambda (window)
	 (when (and (setq this-value (window-parameter window parameter))
		    (or (not value) (equal value this-value)))
	   (throw 'found window)))
       frame any))))

;;; Atomic windows.
(defun window-atom-root (&optional window)
  "Return root of atomic window WINDOW is a part of.
WINDOW can be any window and defaults to the selected one.
Return nil if WINDOW is not part of a atomic window."
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  (setq window (window-normalize-any-window window))
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  (let (root)
    (while (and window (window-parameter window 'window-atom))
      (setq root window)
      (setq window (window-parent window)))
    root))

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(defun window-make-atom (window)
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  "Make WINDOW an atomic window.
WINDOW must be an internal window.  Return WINDOW."
  (if (not (window-child window))
      (error "Window %s is not an internal window" window)
    (walk-window-subtree
     (lambda (window)
       (set-window-parameter window 'window-atom t))
     window t)
    window))

(defun window-atom-check-1 (window)
  "Subroutine of `window-atom-check'."
  (when window
    (if (window-parameter window 'window-atom)
	(let ((count 0))
	  (when (or (catch 'reset
		      (walk-window-subtree
		       (lambda (window)
			 (if (window-parameter window 'window-atom)
			     (setq count (1+ count))
			   (throw 'reset t)))
		       window t))
		    ;; count >= 1 must hold here.  If there's no other
		    ;; window around dissolve this atomic window.
		    (= count 1))
	    ;; Dissolve atomic window.
	    (walk-window-subtree
	     (lambda (window)
	       (set-window-parameter window 'window-atom nil))
	     window t)))
      ;; Check children.
      (unless (window-buffer window)
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	(window-atom-check-1 (window-left-child window))
	(window-atom-check-1 (window-top-child window))))
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    ;; Check right sibling
    (window-atom-check-1 (window-right window))))

(defun window-atom-check (&optional frame)
  "Check atomicity of all windows on FRAME.
FRAME defaults to the selected frame.  If an atomic window is
wrongly configured, reset the atomicity of all its subwindows to
nil.  An atomic window is wrongly configured if it has no
subwindows or one of its subwindows is not atomic."
  (window-atom-check-1 (frame-root-window frame)))

;; Side windows.
(defvar window-sides '(left top right bottom)
  "Window sides.")

(defcustom window-sides-vertical nil
  "If non-nil, left and right side windows are full height.
Otherwise, top and bottom side windows are full width."
  :type 'boolean
  :group 'windows
  :version "24.1")

(defcustom window-sides-slots '(nil nil nil nil)
  "Maximum number of side window slots.
The value is a list of four elements specifying the number of
side window slots on \(in this order) the left, top, right and
bottom side of each frame.  If an element is a number, this means
to display at most that many side windows on the corresponding
side.  If an element is nil, this means there's no bound on the
number of slots on that side."
  :risky t
  :type
  '(list
    :value (nil nil nil nil)
    (choice
     :tag "Left"
     :help-echo "Maximum slots of left side window."
     :value nil
     :format "%[Left%] %v\n"
     (const :tag "Unlimited" :format "%t" nil)
     (integer :tag "Number" :value 2 :size 5))
    (choice
     :tag "Top"
     :help-echo "Maximum slots of top side window."
     :value nil
     :format "%[Top%] %v\n"
     (const :tag "Unlimited" :format "%t" nil)
     (integer :tag "Number" :value 3 :size 5))
    (choice
     :tag "Right"
     :help-echo "Maximum slots of right side window."
     :value nil
     :format "%[Right%] %v\n"
     (const :tag "Unlimited" :format "%t" nil)
     (integer :tag "Number" :value 2 :size 5))
    (choice
     :tag "Bottom"
     :help-echo "Maximum slots of bottom side window."
     :value nil
     :format "%[Bottom%] %v\n"
     (const :tag "Unlimited" :format "%t" nil)
     (integer :tag "Number" :value 3 :size 5)))
  :group 'windows)

(defun window-side-check (&optional frame)
  "Check the window-side parameter of all windows on FRAME.
FRAME defaults to the selected frame.  If the configuration is
invalid, reset all window-side parameters to nil.

A valid configuration has to preserve the following invariant:

- If a window has a non-nil window-side parameter, it must have a
  parent window and the parent window's window-side parameter
  must be either nil or the same as for window.

- If windows with non-nil window-side parameters exist, there
  must be at most one window of each side and non-side with a
  parent whose window-side parameter is nil and there must be no
  leaf window whose window-side parameter is nil."
  (let (normal none left top right bottom
	side parent parent-side code)
    (when (or (catch 'reset
		(walk-window-tree
		 (lambda (window)
		   (setq side (window-parameter window 'window-side))
		   (setq parent (window-parent window))
		   (setq parent-side
			 (and parent (window-parameter parent 'window-side)))
		   ;; The following `cond' seems a bit tedious, but I'd
		   ;; rather stick to using just the stack.
		   (cond
		    (parent-side
		     (when (not (eq parent-side side))
		       ;; A parent whose window-side is non-nil must
		       ;; have a child with the same window-side.
		       (throw 'reset t)))
		    ;; Now check that there's more than one main window
		    ;; for any of none, left, top, right and bottom.
		    ((eq side 'none)
		     (if none
			 (throw 'reset t)
		       (setq none t)))
		    ((eq side 'left)
		     (if left
			 (throw 'reset t)
		       (setq left t)))
		    ((eq side 'top)
		     (if top
			 (throw 'reset t)
		       (setq top t)))
		    ((eq side 'right)
		     (if right
			 (throw 'reset t)
		       (setq right t)))
		    ((eq side 'bottom)
		     (if bottom
			 (throw 'reset t)
		       (setq bottom t)))
		    ((window-buffer window)
		     ;; A leaf window without window-side parameter,
		     ;; record its existence.
		     (setq normal t))))
		 frame t))
	      (if none
		  ;; At least one non-side window exists, so there must
		  ;; be at least one side-window and no normal window.
		  (or (not (or left top right bottom)) normal)
		;; No non-side window exists, so there must be no side
		;; window either.
		(or left top right bottom)))
      (walk-window-tree
       (lambda (window)
	 (set-window-parameter window 'window-side nil))
       frame t))))

(defun window-check (&optional frame)
  "Check atomic and side windows on FRAME.
FRAME defaults to the selected frame."
  (window-side-check frame)
  (window-atom-check frame))

;;; Window sizes.
(defvar window-size-fixed nil
  "Non-nil in a buffer means windows displaying the buffer are fixed-size.
If the value is `height', then only the window's height is fixed.
If the value is `width', then only the window's width is fixed.
Any other non-nil value fixes both the width and the height.

Emacs won't change the size of any window displaying that buffer,
unless it has no other choice \(like when deleting a neighboring
window).")
(make-variable-buffer-local 'window-size-fixed)

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(defsubst window-size-ignore (window ignore)
  "Return non-nil if IGNORE says to ignore size restrictions for WINDOW."
  (if (window-any-p ignore) (eq window ignore) ignore))

(defun window-min-size (&optional window horizontal ignore)
  "Return the minimum number of lines of WINDOW.
WINDOW can be an arbitrary window and defaults to the selected
one.  Optional argument HORIZONTAL non-nil means return the
minimum number of columns of WINDOW.

Optional argument IGNORE non-nil means ignore any restrictions
imposed by fixed size windows, `window-min-height' or
`window-min-width' settings.  IGNORE equal `safe' means live
windows may get as small as `window-safe-min-height' lines and
`window-safe-min-width' columns.  IGNORE a window means ignore
restrictions for that window only."
  (window-min-size-1
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   (window-normalize-any-window window) horizontal ignore))
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(defun window-min-size-1 (window horizontal ignore)
  "Internal function of `window-min-size'."
  (let ((sub (window-child window)))
    (if sub
	(let ((value 0))
	  ;; WINDOW is an internal window.
	  (if (window-iso-combined-p sub horizontal)
	      ;; The minimum size of an iso-combination is the sum of
	      ;; the minimum sizes of its subwindows.
	      (while sub
		(setq value (+ value
			       (window-min-size-1 sub horizontal ignore)))
		(setq sub (window-right sub)))
	    ;; The minimum size of an ortho-combination is the maximum of
	    ;; the minimum sizes of its subwindows.
	    (while sub
	      (setq value (max value
			       (window-min-size-1 sub horizontal ignore)))
	      (setq sub (window-right sub))))
	  value)
      (with-current-buffer (window-buffer window)
	(cond
	 ((and (not (window-size-ignore window ignore))
	       (window-size-fixed-p window horizontal))
	  ;; The minimum size of a fixed size window is its size.
	  (window-total-size window horizontal))
	 ((or (eq ignore 'safe) (eq ignore window))
	  ;; If IGNORE equals `safe' or WINDOW return the safe values.
	  (if horizontal window-safe-min-width window-safe-min-height))
	 (horizontal
	  ;; For the minimum width of a window take fringes and
	  ;; scroll-bars into account.  This is questionable and should
	  ;; be removed as soon as we are able to split (and resize)
	  ;; windows such that the new (or resized) windows can get a
	  ;; size less than the user-specified `window-min-height' and
	  ;; `window-min-width'.
	  (let ((frame (window-frame window))
		(fringes (window-fringes window))
		(scroll-bars (window-scroll-bars window)))
	    (max
	     (+ window-safe-min-width
		(ceiling (car fringes) (frame-char-width frame))
		(ceiling (cadr fringes) (frame-char-width frame))
		(cond
		 ((memq (nth 2 scroll-bars) '(left right))
		  (nth 1 scroll-bars))
		 ((memq (frame-parameter frame 'vertical-scroll-bars)
			'(left right))
		  (ceiling (or (frame-parameter frame 'scroll-bar-width) 14)
			   (frame-char-width)))
		 (t 0)))
	     (if (and (not (window-size-ignore window ignore))
		      (numberp window-min-width))
		 window-min-width
	       0))))
	 (t
	  ;; For the minimum height of a window take any mode- or
	  ;; header-line into account.
	  (max (+ window-safe-min-height
		  (if header-line-format 1 0)
		  (if mode-line-format 1 0))
	       (if (and (not (window-size-ignore window ignore))
			(numberp window-min-height))
		   window-min-height
		 0))))))))

(defun window-sizable (window delta &optional horizontal ignore)
  "Return DELTA if DELTA lines can be added to WINDOW.
Optional argument HORIZONTAL non-nil means return DELTA if DELTA
columns can be added to WINDOW.  A return value of zero means
that no lines (or columns) can be added to WINDOW.

This function looks only at WINDOW and its subwindows.  The
function `window-resizable' looks at other windows as well.

DELTA positive means WINDOW shall be enlarged by DELTA lines or
columns.  If WINDOW cannot be enlarged by DELTA lines or columns
return the maximum value in the range 0..DELTA by which WINDOW
can be enlarged.

DELTA negative means WINDOW shall be shrunk by -DELTA lines or
columns.  If WINDOW cannot be shrunk by -DELTA lines or columns,
return the minimum value in the range DELTA..0 by which WINDOW
can be shrunk.

Optional argument IGNORE non-nil means ignore any restrictions
imposed by fixed size windows, `window-min-height' or
`window-min-width' settings.  IGNORE equal `safe' means live
windows may get as small as `window-safe-min-height' lines and
`window-safe-min-width' columns.  IGNORE any window means ignore
restrictions for that window only."
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  (setq window (window-normalize-any-window window))
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  (cond
   ((< delta 0)
    (max (- (window-min-size window horizontal ignore)
	    (window-total-size window horizontal))
	 delta))
   ((window-size-ignore window ignore)
    delta)
   ((> delta 0)
    (if (window-size-fixed-p window horizontal)
	0
      delta))
   (t 0)))

(defsubst window-sizable-p (window delta &optional horizontal ignore)
  "Return t if WINDOW can be resized by DELTA lines.
For the meaning of the arguments of this function see the
doc-string of `window-sizable'."
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  (setq window (window-normalize-any-window window))
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  (if (> delta 0)
      (>= (window-sizable window delta horizontal ignore) delta)
    (<= (window-sizable window delta horizontal ignore) delta)))

(defun window-size-fixed-1 (window horizontal)
  "Internal function for `window-size-fixed-p'."
  (let ((sub (window-child window)))
    (catch 'fixed
      (if sub
	  ;; WINDOW is an internal window.
	  (if (window-iso-combined-p sub horizontal)
	      ;; An iso-combination is fixed size if all its subwindows
	      ;; are fixed-size.
	      (progn
		(while sub
		  (unless (window-size-fixed-1 sub horizontal)
		    ;; We found a non-fixed-size subwindow, so WINDOW's
		    ;; size is not fixed.
		    (throw 'fixed nil))
		  (setq sub (window-right sub)))
		;; All subwindows are fixed-size, so WINDOW's size is
		;; fixed.
		(throw 'fixed t))
	    ;; An ortho-combination is fixed-size if at least one of its
	    ;; subwindows is fixed-size.
	    (while sub
	      (when (window-size-fixed-1 sub horizontal)
		;; We found a fixed-size subwindow, so WINDOW's size is
		;; fixed.
		(throw 'fixed t))
	      (setq sub (window-right sub))))
	;; WINDOW is a live window.
	(with-current-buffer (window-buffer window)
	  (if horizontal
	      (memq window-size-fixed '(width t))
	    (memq window-size-fixed '(height t))))))))

(defun window-size-fixed-p (&optional window horizontal)
  "Return non-nil if WINDOW's height is fixed.
WINDOW can be an arbitrary window and defaults to the selected
window.  Optional argument HORIZONTAL non-nil means return
non-nil if WINDOW's width is fixed.

If this function returns nil, this does not necessarily mean that
WINDOW can be resized in the desired direction.  The functions
`window-resizable' and `window-resizable-p' will tell that."
  (window-size-fixed-1
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   (window-normalize-any-window window) horizontal))
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(defun window-min-delta-1 (window delta &optional horizontal ignore trail noup)
  "Internal function for `window-min-delta'."
  (if (not (window-parent window))
      ;; If we can't go up, return zero.
      0
    ;; Else try to find a non-fixed-size sibling of WINDOW.
    (let* ((parent (window-parent window))
	   (sub (window-child parent)))
      (catch 'done
	(if (window-iso-combined-p sub horizontal)
	    ;; In an iso-combination throw DELTA if we find at least one
	    ;; subwindow and that subwindow is either not of fixed-size
	    ;; or we can ignore fixed-sizeness.
	    (let ((skip (eq trail 'after)))
	      (while sub
		(cond
		 ((eq sub window)
		  (setq skip (eq trail 'before)))
		 (skip)
		 ((and (not (window-size-ignore window ignore))
		       (window-size-fixed-p sub horizontal)))
		 (t
		  ;; We found a non-fixed-size subwindow.
		  (throw 'done delta)))
		(setq sub (window-right sub))))
	  ;; In an ortho-combination set DELTA to the minimum value by
	  ;; which other subwindows can shrink.
	  (while sub
	    (unless (eq sub window)
	      (setq delta
		    (min delta
			 (- (window-total-size sub horizontal)
			    (window-min-size sub horizontal ignore)))))
	    (setq sub (window-right sub))))
	(if noup
	    delta
	  (window-min-delta-1 parent delta horizontal ignore trail))))))

(defun window-min-delta (&optional window horizontal ignore trail noup nodown)
  "Return number of lines by which WINDOW can be shrunk.
WINDOW can be an arbitrary window and defaults to the selected
window.  Return zero if WINDOW cannot be shrunk.

Optional argument HORIZONTAL non-nil means return number of
columns by which WINDOW can be shrunk.

Optional argument IGNORE non-nil means ignore any restrictions
imposed by fixed size windows, `window-min-height' or
`window-min-width' settings.  IGNORE a window means ignore
restrictions for that window only.  IGNORE equal `safe' means
live windows may get as small as `window-safe-min-height' lines
and `window-safe-min-width' columns.

Optional argument TRAIL `before' means only windows to the left
of or above WINDOW can be enlarged.  Optional argument TRAIL
`after' means only windows to the right of or below WINDOW can be
enlarged.

Optional argument NOUP non-nil means don't go up in the window
tree but try to enlarge windows within WINDOW's combination only.

Optional argument NODOWN non-nil means don't check whether WINDOW
itself \(and its subwindows) can be shrunk; check only whether at
least one other windows can be enlarged appropriately."
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  (setq window (window-normalize-any-window window))
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  (let ((size (window-total-size window horizontal))
	(minimum (window-min-size window horizontal ignore)))
    (cond
     (nodown
      ;; If NODOWN is t, try to recover the entire size of WINDOW.
      (window-min-delta-1 window size horizontal ignore trail noup))
     ((= size minimum)
      ;; If NODOWN is nil and WINDOW's size is already at its minimum,
      ;; there's nothing to recover.
      0)
     (t
      ;; Otherwise, try to recover whatever WINDOW is larger than its
      ;; minimum size.
      (window-min-delta-1
       window (- size minimum) horizontal ignore trail noup)))))

(defun window-max-delta-1 (window delta &optional horizontal ignore trail noup)
  "Internal function of `window-max-delta'."
  (if (not (window-parent window))
      ;; Can't go up.  Return DELTA.
      delta
    (let* ((parent (window-parent window))
	   (sub (window-child parent)))
      (catch 'fixed
	(if (window-iso-combined-p sub horizontal)
	    ;; For an iso-combination calculate how much we can get from
	    ;; other subwindows.
	    (let ((skip (eq trail 'after)))
	      (while sub
		(cond
		 ((eq sub window)
		  (setq skip (eq trail 'before)))
		 (skip)
		 (t
		  (setq delta
			(+ delta
			   (- (window-total-size sub horizontal)
			      (window-min-size sub horizontal ignore))))))
		(setq sub (window-right sub))))
	  ;; For an ortho-combination throw DELTA when at least one
	  ;; subwindow is fixed-size.
	  (while sub
	    (when (and (not (eq sub window))
		       (not (window-size-ignore sub ignore))
		       (window-size-fixed-p sub horizontal))
	      (throw 'fixed delta))
	    (setq sub (window-right sub))))
	(if noup
	    ;; When NOUP is nil, DELTA is all we can get.
	    delta
	  ;; Else try with parent of WINDOW, passing the DELTA we
	  ;; recovered so far.
	  (window-max-delta-1 parent delta horizontal ignore trail))))))

(defun window-max-delta (&optional window horizontal ignore trail noup nodown)
  "Return maximum number of lines WINDOW by which WINDOW can be enlarged.
WINDOW can be an arbitrary window and defaults to the selected
window.  The return value is zero if WINDOW cannot be enlarged.

Optional argument HORIZONTAL non-nil means return maximum number
of columns by which WINDOW can be enlarged.

Optional argument IGNORE non-nil means ignore any restrictions
imposed by fixed size windows, `window-min-height' or
`window-min-width' settings.  IGNORE a window means ignore
restrictions for that window only.  IGNORE equal `safe' means
live windows may get as small as `window-safe-min-height' lines
and `window-safe-min-width' columns.

Optional argument TRAIL `before' means only windows to the left
of or below WINDOW can be shrunk.  Optional argument TRAIL
`after' means only windows to the right of or above WINDOW can be
shrunk.

Optional argument NOUP non-nil means don't go up in the window
tree but try to obtain the entire space from windows within
WINDOW's combination.

Optional argument NODOWN non-nil means do not check whether
WINDOW itself \(and its subwindows) can be enlarged; check only
whether other windows can be shrunk appropriately."
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  (setq window (window-normalize-any-window window))
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  (if (and (not (window-size-ignore window ignore))
	   (not nodown) (window-size-fixed-p window horizontal))
      ;; With IGNORE and NOWDON nil return zero if WINDOW has fixed
      ;; size.
      0
    ;; WINDOW has no fixed size.
    (window-max-delta-1 window 0 horizontal ignore trail noup)))

;; Make NOUP also inhibit the min-size check.
(defun window-resizable (window delta &optional horizontal ignore trail noup nodown)
  "Return DELTA if WINDOW can be resized vertically by DELTA lines.
Optional argument HORIZONTAL non-nil means return DELTA if WINDOW
can be resized horizontally by DELTA columns.  A return value of
zero means that WINDOW is not resizable.

DELTA positive means WINDOW shall be enlarged by DELTA lines or
columns.  If WINDOW cannot be enlarged by DELTA lines or columns
return the maximum value in the range 0..DELTA by which WINDOW
can be enlarged.

DELTA negative means WINDOW shall be shrunk by -DELTA lines or
columns.  If WINDOW cannot be shrunk by -DELTA lines or columns,
return the minimum value in the range DELTA..0 that can be used
for shrinking WINDOW.

Optional argument IGNORE non-nil means ignore any restrictions
imposed by fixed size windows, `window-min-height' or
`window-min-width' settings.  IGNORE a window means ignore
restrictions for that window only.  IGNORE equal `safe' means
live windows may get as small as `window-safe-min-height' lines
and `window-safe-min-width' columns.

Optional argument TRAIL `before' means only windows to the left
of or below WINDOW can be shrunk.  Optional argument TRAIL
`after' means only windows to the right of or above WINDOW can be
shrunk.

Optional argument NOUP non-nil means don't go up in the window
tree but try to distribute the space among the other windows
within WINDOW's combination.

Optional argument NODOWN non-nil means don't check whether WINDOW
and its subwindows can be resized."
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  (setq window (window-normalize-any-window window))
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  (cond
   ((< delta 0)
    (max (- (window-min-delta window horizontal ignore trail noup nodown))
	 delta))
   ((> delta 0)
    (min (window-max-delta window horizontal ignore trail noup nodown)
	 delta))
   (t 0)))

(defun window-resizable-p (window delta &optional horizontal ignore trail noup nodown)
  "Return t if WINDOW can be resized vertically by DELTA lines.
For the meaning of the arguments of this function see the
doc-string of `window-resizable'."
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  (setq window (window-normalize-any-window window))
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  (if (> delta 0)
      (>= (window-resizable window delta horizontal ignore trail noup nodown)
	  delta)
    (<= (window-resizable window delta horizontal ignore trail noup nodown)
	delta)))

(defsubst window-total-height (&optional window)
  "Return the total number of lines of WINDOW.
WINDOW can be any window and defaults to the selected one.  The
return value includes WINDOW's mode line and header line, if any.
If WINDOW is internal the return value is the sum of the total
number of lines of WINDOW's child windows if these are vertically
combined and the height of WINDOW's first child otherwise.

Note: This function does not take into account the value of
`line-spacing' when calculating the number of lines in WINDOW."
  (window-total-size window))
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;; Eventually we should make `window-height' obsolete.
(defalias 'window-height 'window-total-height)

937
;; See discussion in bug#4543.
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(defsubst window-full-height-p (&optional window)
  "Return t if WINDOW is as high as the containing frame.
More precisely, return t if and only if the total height of
WINDOW equals the total height of the root window of WINDOW's
frame.  WINDOW can be any window and defaults to the selected
one."
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  (setq window (window-normalize-any-window window))
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  (= (window-total-size window)
     (window-total-size (frame-root-window window))))

(defsubst window-total-width (&optional window)
  "Return the total number of columns of WINDOW.
WINDOW can be any window and defaults to the selected one.  The
return value includes any vertical dividers or scrollbars of
WINDOW.  If WINDOW is internal, the return value is the sum of
the total number of columns of WINDOW's child windows if these
are horizontally combined and the width of WINDOW's first child
otherwise."
  (window-total-size window t))

(defsubst window-full-width-p (&optional window)
  "Return t if WINDOW is as wide as the containing frame.
More precisely, return t if and only if the total width of WINDOW
equals the total width of the root window of WINDOW's frame.
WINDOW can be any window and defaults to the selected one."
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  (setq window (window-normalize-any-window window))
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  (= (window-total-size window t)
     (window-total-size (frame-root-window window) t)))

(defsubst window-body-height (&optional window)
  "Return the number of lines of WINDOW's body.
WINDOW must be a live window and defaults to the selected one.

The return value does not include WINDOW's mode line and header
line, if any.  If a line at the bottom of the window is only
partially visible, that line is included in the return value.  If
you do not want to include a partially visible bottom line in the
return value, use `window-text-height' instead."
  (window-body-size window))

(defsubst window-body-width (&optional window)
  "Return the number of columns of WINDOW's body.
WINDOW must be a live window and defaults to the selected one.

The return value does not include any vertical dividers or scroll
bars owned by WINDOW.  On a window-system the return value does
not include the number of columns used for WINDOW's fringes or
display margins either."
  (window-body-size window t))
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;; Eventually we should make `window-height' obsolete.
(defalias 'window-width 'window-body-width)

991 992
(defun window-current-scroll-bars (&optional window)
  "Return the current scroll bar settings for WINDOW.
993
WINDOW must be a live window and defaults to the selected one.
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The return value is a cons cell (VERTICAL . HORIZONTAL) where
VERTICAL specifies the current location of the vertical scroll
bars (`left', `right', or nil), and HORIZONTAL specifies the
current location of the horizontal scroll bars (`top', `bottom',
or nil).

Unlike `window-scroll-bars', this function reports the scroll bar
type actually used, once frame defaults and `scroll-bar-mode' are
taken into account."
1004
  (setq window (window-normalize-live-window window))
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  (let ((vert (nth 2 (window-scroll-bars window)))
	(hor nil))
    (when (or (eq vert t) (eq hor t))
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      (let ((fcsb (frame-current-scroll-bars (window-frame window))))
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	(if (eq vert t)
	    (setq vert (car fcsb)))
	(if (eq hor t)
	    (setq hor (cdr fcsb)))))
    (cons vert hor)))

(defun walk-windows (proc &optional minibuf all-frames)
1016
  "Cycle through all live windows, calling PROC for each one.
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PROC must specify a function with a window as its sole argument.
The optional arguments MINIBUF and ALL-FRAMES specify the set of
1019
windows to include in the walk.
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MINIBUF t means include the minibuffer window even if the
minibuffer is not active.  MINIBUF nil or omitted means include
the minibuffer window only if the minibuffer is active.  Any
other value means do not include the minibuffer window even if
the minibuffer is active.

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ALL-FRAMES nil or omitted means consider all windows on the
selected frame, plus the minibuffer window if specified by the
MINIBUF argument.  If the minibuffer counts, consider all windows
on all frames that share that minibuffer too.  The following
non-nil values of ALL-FRAMES have special meanings:

- t means consider all windows on all existing frames.

- `visible' means consider all windows on all visible frames on
  the current terminal.

- 0 (the number zero) means consider all windows on all visible
  and iconified frames on the current terminal.

- A frame means consider all windows on that frame only.

Anything else means consider all windows on the selected frame
and no others.
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This function changes neither the order of recently selected
windows nor the buffer list."
  ;; If we start from the minibuffer window, don't fail to come
  ;; back to it.
  (when (window-minibuffer-p (selected-window))
    (setq minibuf t))
  ;; Make sure to not mess up the order of recently selected
  ;; windows.  Use `save-selected-window' and `select-window'
  ;; with second argument non-nil for this purpose.
  (save-selected-window
    (when (framep all-frames)
      (select-window (frame-first-window all-frames) 'norecord))
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    (dolist (walk-windows-window (window-list-1 nil minibuf all-frames))
      (funcall proc walk-windows-window))))

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(defun window-point-1 (&optional window)
  "Return value of WINDOW's point.
WINDOW can be any live window and defaults to the selected one.

This function is like `window-point' with one exception: If
WINDOW is selected, it returns the value of `point' of WINDOW's
buffer regardless of whether that buffer is current or not."
  (setq window (window-normalize-live-window window))
  (if (eq window (selected-window))
      (with-current-buffer (window-buffer window)
	(point))
    (window-point window)))

(defun set-window-point-1 (window pos)
  "Set value of WINDOW's point to POS.
WINDOW can be any live window and defaults to the selected one.

This function is like `set-window-point' with one exception: If
WINDOW is selected, it moves `point' of WINDOW's buffer to POS
regardless of whether that buffer is current or not."
  (setq window (window-normalize-live-window window))
  (if (eq window (selected-window))
      (with-current-buffer (window-buffer window)
	(goto-char pos))
    (set-window-point window pos)))

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(defun window-at-side-p (&optional window side)
  "Return t if WINDOW is at SIDE of its containing frame.
WINDOW can be any window and defaults to the selected one.  SIDE
can be any of the symbols `left', `top', `right' or `bottom'.
The default value nil is handled like `bottom'."
  (setq window (window-normalize-any-window window))
  (let ((edge
	 (cond
	  ((eq side 'left) 0)
	  ((eq side 'top) 1)
	  ((eq side 'right) 2)
	  ((memq side '(bottom nil)) 3))))
    (= (nth edge (window-edges window))
       (nth edge (window-edges (frame-root-window window))))))

(defun windows-at-side (&optional frame side)
  "Return list of all windows on SIDE of FRAME.
FRAME must be a live frame and defaults to the selected frame.
SIDE can be any of the symbols `left', `top', `right' or
`bottom'.  The default value nil is handled like `bottom'."
  (setq frame (window-normalize-frame frame))
  (let (windows)
    (walk-window-tree
     (lambda (window)
       (when (window-at-side-p window side)
	 (setq windows (cons window windows))))
     frame)
    (nreverse windows)))

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(defun window-in-direction-2 (window posn &optional horizontal)
  "Support function for `window-in-direction'."
  (if horizontal
      (let ((top (window-top-line window)))
	(if (> top posn)
	    (- top posn)
	  (- posn top (window-total-height window))))
    (let ((left (window-left-column window)))
      (if (> left posn)
	  (- left posn)
	(- posn left (window-total-width window))))))

(defun window-in-direction (direction &optional window ignore)
  "Return window in DIRECTION as seen from WINDOW.
DIRECTION must be one of `above', `below', `left' or `right'.
WINDOW must be a live window and defaults to the selected one.
IGNORE, when non-nil means a window can be returned even if its
`no-other-window' parameter is non-nil."
1134
  (setq window (window-normalize-live-window window))
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  (unless (memq direction '(above below left right))
    (error "Wrong direction %s" direction))
  (let* ((frame (window-frame window))
	 (hor (memq direction '(left right)))
	 (first (if hor
		    (window-left-column window)
		  (window-top-line window)))
	 (last (+ first (if hor
			    (window-total-width window)
			  (window-total-height window))))
1145
	 (posn-cons (nth 6 (posn-at-point (window-point-1 window) window)))
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	 ;; The column / row value of `posn-at-point' can be nil for the
	 ;; mini-window, guard against that.
	 (posn (if hor
		   (+ (or (cdr posn-cons) 1) (window-top-line window))
		 (+ (or (car posn-cons) 1) (window-left-column window))))
	 (best-edge
	  (cond
	   ((eq direction 'below) (frame-height frame))
	   ((eq direction 'right) (frame-width frame))
	   (t -1)))
	 (best-edge-2 best-edge)
	 (best-diff-2 (if hor (frame-height frame) (frame-width frame)))
	 best best-2 best-diff-2-new)
    (walk-window-tree
     (lambda (w)
       (let* ((w-top (window-top-line w))
	      (w-left (window-left-column w)))
	 (cond
	  ((or (eq window w)
	       ;; Ignore ourselves.
	       (and (window-parameter w 'no-other-window)
		    ;; Ignore W unless IGNORE is non-nil.
		    (not ignore))))
	  (hor
	   (cond
	    ((and (<= w-top posn)
		  (< posn (+ w-top (window-total-height w))))
	     ;; W is to the left or right of WINDOW and covers POSN.
	     (when (or (and (eq direction 'left)
			    (<= w-left first) (> w-left best-edge))
		       (and (eq direction 'right)
			    (>= w-left last) (< w-left best-edge)))
	       (setq best-edge w-left)
	       (setq best w)))
	    ((and (or (and (eq direction 'left)
			   (<= (+ w-left (window-total-width w)) first))
		      (and (eq direction 'right) (<= last w-left)))
		  ;; W is to the left or right of WINDOW but does not
		  ;; cover POSN.
		  (setq best-diff-2-new
			(window-in-direction-2 w posn hor))
		  (or (< best-diff-2-new best-diff-2)
		      (and (= best-diff-2-new best-diff-2)
			   (if (eq direction 'left)
			       (> w-left best-edge-2)
			     (< w-left best-edge-2)))))
	     (setq best-edge-2 w-left)
	     (setq best-diff-2 best-diff-2-new)
	     (setq best-2 w))))
	  (t
	   (cond
	    ((and (<= w-left posn)
		  (< posn (+ w-left (window-total-width w))))
	     ;; W is above or below WINDOW and covers POSN.
	     (when (or (and (eq direction 'above)
			    (<= w-top first) (> w-top best-edge))
		       (and (eq direction 'below)
			    (>= w-top first) (< w-top best-edge)))
	       (setq best-edge w-top)
	       (setq best w)))
	    ((and (or (and (eq direction 'above)
			   (<= (+ w-top (window-total-height w)) first))
		      (and (eq direction 'below) (<= last w-top)))
		  ;; W is above or below WINDOW but does not cover POSN.
		  (setq best-diff-2-new
			(window-in-direction-2 w posn hor))
		  (or (< best-diff-2-new best-diff-2)
		      (and (= best-diff-2-new best-diff-2)
			   (if (eq direction 'above)
			       (> w-top best-edge-2)
			     (< w-top best-edge-2)))))
	     (setq best-edge-2 w-top)
	     (setq best-diff-2 best-diff-2-new)
	     (setq best-2 w)))))))
     (window-frame window))
    (or best best-2)))
1222

1223
(defun get-window-with-predicate (predicate &optional minibuf all-frames default)
1224 1225 1226 1227
  "Return a live window satisfying PREDICATE.
More precisely, cycle through all windows calling the function
PREDICATE on each one of them with the window as its sole
argument.  Return the first window for which PREDICATE returns
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non-nil.  Windows are scanned starting with the window following
the selcted window.  If no window satisfies PREDICATE, return
DEFAULT.

MINIBUF t means include the minibuffer window even if the
minibuffer is not active.  MINIBUF nil or omitted means include
the minibuffer window only if the minibuffer is active.  Any
other value means do not include the minibuffer window even if
the minibuffer is active.
1237 1238 1239 1240 1241 1242

ALL-FRAMES nil or omitted means consider all windows on the selected
frame, plus the minibuffer window if specified by the MINIBUF
argument.  If the minibuffer counts, consider all windows on all
frames that share that minibuffer too.  The following non-nil
values of ALL-FRAMES have special meanings:
1243

1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255
- t means consider all windows on all existing frames.

- `visible' means consider all windows on all visible frames on
  the current terminal.

- 0 (the number zero) means consider all windows on all visible
  and iconified frames on the current terminal.

- A frame means consider all windows on that frame only.

Anything else means consider all windows on the selected frame
and no others."
1256
  (catch 'found
1257 1258 1259
    (dolist (window (window-list-1
		     (next-window nil minibuf all-frames)
		     minibuf all-frames))
1260 1261
      (when (funcall predicate window)
	(throw 'found window)))
1262 1263 1264 1265
    default))

(defalias 'some-window 'get-window-with-predicate)

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(defun get-lru-window (&optional all-frames dedicated)
   "Return the least recently used window on frames specified by ALL-FRAMES.
Return a full-width window if possible.  A minibuffer window is
never a candidate.  A dedicated window is never a candidate
unless DEDICATED is non-nil, so if all windows are dedicated, the
value is nil.  Avoid returning the selected window if possible.

The following non-nil values of the optional argument ALL-FRAMES
have special meanings:

- t means consider all windows on all existing frames.

- `visible' means consider all windows on all visible frames on
  the current terminal.

- 0 (the number zero) means consider all windows on all visible
  and iconified frames on the current terminal.

- A frame means consider all windows on that frame only.

Any other value of ALL-FRAMES means consider all windows on the
selected frame and no others."
   (let (best-window best-time second-best-window second-best-time time)
1289
    (dolist (window (window-list-1 nil 'nomini all-frames))
1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301
      (when (or dedicated (not (window-dedicated-p window)))
	(setq time (window-use-time window))
	(if (or (eq window (selected-window))
		(not (window-full-width-p window)))
	    (when (or (not second-best-time) (< time second-best-time))
	      (setq second-best-time time)
	      (setq second-best-window window))
	  (when (or (not best-time) (< time best-time))
	    (setq best-time time)
	    (setq best-window window)))))
    (or best-window second-best-window)))

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(defun get-mru-window (&optional all-frames)
   "Return the most recently used window on frames specified by ALL-FRAMES.
Do not return a minibuffer window.

The following non-nil values of the optional argument ALL-FRAMES
have special meanings:

- t means consider all windows on all existing frames.

- `visible' means consider all windows on all visible frames on
  the current terminal.

- 0 (the number zero) means consider all windows on all visible
  and iconified frames on the current terminal.

- A frame means consider all windows on that frame only.

Any other value of ALL-FRAMES means consider all windows on the
selected frame and no others."
   (let (best-window best-time time)
1322
    (dolist (window (window-list-1 nil 'nomini all-frames))
1323 1324 1325 1326 1327 1328
      (setq time (window-use-time window))
      (when (or (not best-time) (> time best-time))
	(setq best-time time)
	(setq best-window window)))
    best-window))

1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351
(defun get-largest-window (&optional all-frames dedicated)
  "Return the largest window on frames specified by ALL-FRAMES.
A minibuffer window is never a candidate.  A dedicated window is
never a candidate unless DEDICATED is non-nil, so if all windows
are dedicated, the value is nil.

The following non-nil values of the optional argument ALL-FRAMES
have special meanings:

- t means consider all windows on all existing frames.

- `visible' means consider all windows on all visible frames on
  the current terminal.

- 0 (the number zero) means consider all windows on all visible
  and iconified frames on the current terminal.

- A frame means consider all windows on that frame only.

Any other value of ALL-FRAMES means consider all windows on the
selected frame and no others."
  (let ((best-size 0)
	best-window size)
1352
    (dolist (window (window-list-1 nil 'nomini all-frames))
1353 1354 1355 1356 1357 1358 1359 1360
      (when (or dedicated (not (window-dedicated-p window)))
	(setq size (* (window-total-size window)
		      (window-total-size window t)))
	(when (> size best-size)
	  (setq best-size size)
	  (setq best-window window))))
    best-window))

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(defun get-buffer-window-list (&optional buffer-or-name minibuf all-frames)
  "Return list of all windows displaying BUFFER-OR-NAME, or nil if none.
BUFFER-OR-NAME may be a buffer or the name of an existing buffer
1364 1365
and defaults to the current buffer.  Windows are scanned starting
with the selected window.
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MINIBUF t means include the minibuffer window even if the
minibuffer is not active.  MINIBUF nil or omitted means include
the minibuffer window only if the minibuffer is active.  Any
other value means do not include the minibuffer window even if
the minibuffer is active.

ALL-FRAMES nil or omitted means consider all windows on the
selected frame, plus the minibuffer window if specified by the
MINIBUF argument.  If the minibuffer counts, consider all windows
on all frames that share that minibuffer too.  The following
non-nil values of ALL-FRAMES have special meanings:

- t means consider all windows on all existing frames.

- `visible' means consider all windows on all visible frames on
  the current terminal.

- 0 (the number zero) means consider all windows on all visible
  and iconified frames on the current terminal.

- A frame means consider all windows on that frame only.

Anything else means consider all windows on the selected frame
and no others."
1391
  (let ((buffer (window-normalize-buffer buffer-or-name))
1392
	windows)
1393
    (dolist (window (window-list-1 (selected-window) minibuf all-frames))
1394 1395 1396
      (when (eq (window-buffer window) buffer)
	(setq windows (cons window windows))))
    (nreverse windows)))
1397 1398 1399 1400

(defun minibuffer-window-active-p (window)
  "Return t if WINDOW is the currently active minibuffer window."
  (eq window (active-minibuffer-window)))
1401

1402
(defun count-windows (&optional minibuf)
1403
   "Return the number of live windows on the selected frame.
1404 1405 1406
The optional argument MINIBUF specifies whether the minibuffer
window shall be counted.  See `walk-windows' for the precise
meaning of this argument."
1407
   (length (window-list-1 nil minibuf)))
1408 1409

;;; Resizing windows.
1410
(defun window--resize-reset (&optional frame horizontal)
1411 1412 1413 1414 1415 1416 1417
  "Reset resize values for all windows on FRAME.
FRAME defaults to the selected frame.

This function stores the current value of `window-total-size' applied
with argument HORIZONTAL in the new total size of all windows on
FRAME.  It also resets the new normal size of each of these
windows."
1418 1419
  (window--resize-reset-1
   (frame-root-window (window-normalize-frame frame)) horizontal))
1420

1421 1422
(defun window--resize-reset-1 (window horizontal)
  "Internal function of `window--resize-reset'."
1423 1424 1425 1426 1427
  ;; Register old size in the new total size.
  (set-window-new-total window (window-total-size window horizontal))
  ;; Reset new normal size.
  (set-window-new-normal window)
  (when (window-child window)
1428
    (window--resize-reset-1 (window-child window) horizontal))
1429
  (when (window-right window)
1430
    (window--resize-reset-1 (window-right window) horizontal)))
1431

1432 1433
;; The following routine is used to manually resize the minibuffer
;; window and is currently used, for example, by ispell.el.
1434
(defun window--resize-mini-window (window delta)
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  "Resize minibuffer window WINDOW by DELTA lines.
If WINDOW cannot be resized by DELTA lines make it as large \(or
as small) as possible but don't signal an error."
  (when (window-minibuffer-p window)
    (let* ((frame (window-frame window))
	   (root (frame-root-window frame))
	   (height (window-total-size window))
	   (min-delta
	    (- (window-total-size root)
	       (window-min-size root))))
      ;; Sanitize DELTA.
      (cond
       ((<= (+ height delta) 0)
	(setq delta (- (- height 1))))
       ((> delta min-delta)
	(setq delta min-delta)))

      ;; Resize now.
1453
      (window--resize-reset frame)
1454 1455 1456
      ;; Ideally we should be able to resize just the last subwindow of
      ;; root here.  See the comment in `resize-root-window-vertically'
      ;; for why we do not do that.
1457
      (window--resize-this-window root (- delta) nil nil t)
1458 1459 1460 1461 1462
      (set-window-new-total window (+ height delta))
      ;; The following routine catches the case where we want to resize
      ;; a minibuffer-only frame.
      (resize-mini-window-internal window))))

1463
(defun window-resize (window delta &optional horizontal ignore)
1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488
  "Resize WINDOW vertically by DELTA lines.
WINDOW can be an arbitrary window and defaults to the selected
one.  An attempt to resize the root window of a frame will raise
an error though.

DELTA a positive number means WINDOW shall be enlarged by DELTA
lines.  DELTA negative means WINDOW shall be shrunk by -DELTA
lines.

Optional argument HORIZONTAL non-nil means resize WINDOW
horizontally by DELTA columns.  In this case a positive DELTA
means enlarge WINDOW by DELTA columns.  DELTA negative means
WINDOW shall be shrunk by -DELTA columns.

Optional argument IGNORE non-nil means ignore any restrictions
imposed by fixed size windows, `window-min-height' or
`window-min-width' settings.  IGNORE any window means ignore
restrictions for that window only.  IGNORE equal `safe' means
live windows may get as small as `window-safe-min-height' lines
and `window-safe-min-width' columns.

This function resizes other windows proportionally and never
deletes any windows.  If you want to move only the low (right)
edge of WINDOW consider using `adjust-window-trailing-edge'
instead."
1489
  (setq window (window-normalize-any-window window))
1490 1491 1492 1493 1494 1495
  (let* ((frame (window-frame window))
	 sibling)
    (cond
     ((eq window (frame-root-window frame))
      (error "Cannot resize the root window of a frame"))
     ((window-minibuffer-p window)
1496
      (window--resize-mini-window window delta))
1497
     ((window-resizable-p window delta horizontal ignore)
1498 1499
      (window--resize-reset frame horizontal)
      (window--resize-this-window window delta horizontal ignore t)
1500 1501 1502 1503 1504 1505 1506 1507 1508 1509
      (if (and (not (window-splits window))
	       (window-iso-combined-p window horizontal)
	       (setq sibling (or (window-right window) (window-left window)))
	       (window-sizable-p sibling (- delta) horizontal ignore))
	  ;; If window-splits returns nil for WINDOW, WINDOW is part of
	  ;; an iso-combination, and WINDOW's neighboring right or left
	  ;; sibling can be resized as requested, resize that sibling.
	  (let ((normal-delta
		 (/ (float delta)
		    (window-total-size (window-parent window) horizontal))))
1510
	    (window--resize-this-window sibling (- delta) horizontal nil t)
1511 1512 1513 1514 1515 1516 1517
	    (set-window-new-normal
	     window (+ (window-normal-size window horizontal)
		       normal-delta))
	    (set-window-new-normal
	     sibling (- (window-normal-size sibling horizontal)
			normal-delta)))
	;; Otherwise, resize all other windows in the same combination.
1518
	(window--resize-siblings window delta horizontal ignore))
1519
      (window-resize-apply frame horizontal))
1520 1521 1522
     (t
      (error "Cannot resize window %s" window)))))

1523
(defsubst window--resize-subwindows-skip-p (window)
1524 1525 1526
  "Return non-nil if WINDOW shall be skipped by resizing routines."
  (memq (window-new-normal window) '(ignore stuck skip)))

1527
(defun window--resize-subwindows-normal (parent horizontal window this-delta &optional trail other-delta)
1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623
  "Set the new normal height of subwindows of window PARENT.
HORIZONTAL non-nil means set the new normal width of these
windows.  WINDOW specifies a subwindow of PARENT that has been
resized by THIS-DELTA lines \(columns).

Optional argument TRAIL either 'before or 'after means set values
for windows before or after WINDOW only.  Optional argument
OTHER-DELTA a number specifies that this many lines \(columns)
have been obtained from \(or returned to) an ancestor window of
PARENT in order to resize WINDOW."
  (let* ((delta-normal
	  (if (and (= (- this-delta) (window-total-size window horizontal))
		   (zerop other-delta))
	      ;; When WINDOW gets deleted and we can return its entire
	      ;; space to its siblings, use WINDOW's normal size as the
	      ;; normal delta.
	      (- (window-normal-size window horizontal))
	    ;; In any other case calculate the normal delta from the
	    ;; relation of THIS-DELTA to the total size of PARENT.
	    (/ (float this-delta) (window-total-size parent horizontal))))
	 (sub (window-child parent))
	 (parent-normal 0.0)
	 (skip (eq trail 'after)))

    ;; Set parent-normal to the sum of the normal sizes of all
    ;; subwindows of PARENT that shall be resized, excluding only WINDOW
    ;; and any windows specified by the optional TRAIL argument.
    (while sub
      (cond
       ((eq sub window)
	(setq skip (eq trail 'before)))
       (skip)
       (t
	(setq parent-normal
	      (+ parent-normal (window-normal-size sub horizontal)))))
      (setq sub (window-right sub)))

    ;; Set the new normal size of all subwindows of PARENT from what
    ;; they should have contributed for recovering THIS-DELTA lines
    ;; (columns).
    (setq sub (window-child parent))
    (setq skip (eq trail 'after))
    (while sub
      (cond
       ((eq sub window)
	(setq skip (eq trail 'before)))
       (skip)
       (t
	(let ((old-normal (window-normal-size sub horizontal)))
	  (set-window-new-normal
	   sub (min 1.0 ; Don't get larger than 1.
		    (max (- old-normal
			    (* (/ old-normal parent-normal)
			       delta-normal))
			 ;; Don't drop below 0.
			 0.0))))))
      (setq sub (window-right sub)))

    (when (numberp other-delta)
      ;; Set the new normal size of windows from what they should have
      ;; contributed for recovering OTHER-DELTA lines (columns).
      (setq delta-normal (/ (float (window-total-size parent horizontal))
			    (+ (window-total-size parent horizontal)
			       other-delta)))
      (setq sub (window-child parent))
      (setq skip (eq trail 'after))
      (while sub
	(cond
	 ((eq sub window)
	  (setq skip (eq trail 'before)))
	 (skip)
	 (t
	  (set-window-new-normal
	   sub (min 1.0 ; Don't get larger than 1.
		    (max (* (window-new-normal sub) delta-normal)
			 ;; Don't drop below 0.
			 0.0)))))
	(setq sub (window-right sub))))

    ;; Set the new normal size of WINDOW to what is left by the sum of
    ;; the normal sizes of its siblings.
    (set-window-new-normal
     window
     (let ((sum 0))
       (setq sub (window-child parent))
       (while sub
	 (cond
	  ((eq sub window))
	  ((not (numberp (window-new-normal sub)))
	   (setq sum (+ sum (window-normal-size sub horizontal))))
	  (t
	   (setq sum (+ sum (window-new-normal sub)))))
	 (setq sub (window-right sub)))
       ;; Don't get larger than 1 or smaller than 0.
       (min 1.0 (max (- 1.0 sum) 0.0))))))

1624
(defun window--resize-subwindows (parent delta &optional horizontal window ignore trail edge)
1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659
  "Resize subwindows of window PARENT vertically by DELTA lines.
PARENT must be a vertically combined internal window.

Optional argument HORIZONTAL non-nil means resize subwindows of
PARENT horizontally by DELTA columns.  In this case PARENT must
be a horizontally combined internal window.

WINDOW, if specified, must denote a child window of PARENT that
is resized by DELTA lines.

Optional argument IGNORE non-nil means ignore any restrictions
imposed by fixed size windows, `window-min-height' or
`window-min-width' settings.  IGNORE equal `safe' means live
windows may get as small as `window-safe-min-height' lines and
`window-safe-min-width' columns.  IGNORE any window means ignore
restrictions for that window only.

Optional arguments TRAIL and EDGE, when non-nil, restrict the set
of windows that shall be resized.  If TRAIL equals `before',
resize only windows on the left or above EDGE.  If TRAIL equals
`after', resize only windows on the right or below EDGE.  Also,
preferably only resize windows adjacent to EDGE.

Return the symbol `normalized' if new normal sizes have been
already set by this routine."
  (let* ((first (window-child parent))
	 (sub first)
	 (parent-total (+ (window-total-size parent horizontal) delta))
	 best-window best-value)

    (if (and edge (memq trail '(before after))
	     (progn
	       (setq sub first)
	       (while (and (window-right sub)
			   (or (and (eq trail 'before)
1660
				    (not (window--resize-subwindows-skip-p
1661 1662
					  (window-right sub))))
			       (and (eq trail 'after)
1663
				    (window--resize-subwindows-skip-p sub))))
1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679
		 (setq sub (window-right sub)))
	       sub)
	     (if horizontal
		 (if (eq trail 'before)
		     (= (+ (window-left-column sub)
			   (window-total-size sub t))
			edge)
		   (= (window-left-column sub) edge))
	       (if (eq trail 'before)
		   (= (+ (window-top-line sub)
			 (window-total-size sub))
		      edge)
		 (= (window-top-line sub) edge)))
	     (window-sizable-p sub delta horizontal ignore))
	;; Resize only windows adjacent to EDGE.
	(progn
1680 1681
	  (window--resize-this-window
	   sub delta horizontal ignore t trail edge)
1682 1683 1684 1685 1686 1687 1688 1689 1690
	  (if (and window (eq (window-parent sub) parent))
	      (progn
		;; Assign new normal sizes.
		(set-window-new-normal
		 sub (/ (float (window-new-total sub)) parent-total))
		(set-window-new-normal
		 window (- (window-normal-size window horizontal)
			   (- (window-new-normal sub)
			      (window-normal-size sub horizontal)))))
1691 1692 1693
	    (window--resize-subwindows-normal
	     parent horizontal sub 0 trail delta))
	  ;; Return 'normalized to notify `window--resize-siblings' that
1694 1695 1696 1697 1698 1699
	  ;; normal sizes have been already set.
	  'normalized)
      ;; Resize all windows proportionally.
      (setq sub first)
      (while sub
	(cond
1700
	 ((or (window--resize-subwindows-skip-p sub)
1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784
	      ;; Ignore windows to skip and fixed-size subwindows - in
	      ;; the latter case make it a window to skip.
	      (and (not ignore)
		   (window-size-fixed-p sub horizontal)
		   (set-window-new-normal sub 'ignore))))
	 ((< delta 0)
	  ;; When shrinking store the number of lines/cols we can get
	  ;; from this window here together with the total/normal size
	  ;; factor.
	  (set-window-new-normal
	   sub
	   (cons
	    ;; We used to call this with NODOWN t, "fixed" 2011-05-11.
	    (window-min-delta sub horizontal ignore trail t) ; t)
	    (- (/ (float (window-total-size sub horizontal))
		  parent-total)
	       (window-normal-size sub horizontal)))))
	 ((> delta 0)
	  ;; When enlarging store the total/normal size factor only
	  (set-window-new-normal
	   sub
	   (- (/ (float (window-total-size sub horizontal))
		 parent-total)
	      (window-normal-size sub horizontal)))))

	(setq sub (window-right sub)))

      (cond
       ((< delta 0)
	;; Shrink windows by delta.
	(setq best-window t)
	(while (and best-window (not (zerop delta)))
	  (setq sub first)
	  (setq best-window nil)
	  (setq best-value most-negative-fixnum)
	  (while sub
	    (when (and (consp (window-new-normal sub))
		       (not (zerop (car (window-new-normal sub))))
		       (> (cdr (window-new-normal sub)) best-value))
	      (setq best-window sub)
	      (setq best-value (cdr (window-new-normal sub))))

	    (setq sub (window-right sub)))

	  (when best-window
	    (setq delta (1+ delta)))
	  (set-window-new-total best-window -1 t)
	  (set-window-new-normal
	   best-window
	   (if (= (car (window-new-normal best-window)) 1)
	       'skip ; We can't shrink best-window any further.
	     (cons (1- (car (window-new-normal best-window)))
		   (- (/ (float (window-new-total best-window))
			 parent-total)
		      (window-normal-size best-window horizontal)))))))
       ((> delta 0)
	;; Enlarge windows by delta.
	(setq best-window t)
	(while (and best-window (not (zerop delta)))
	  (setq sub first)
	  (setq best-window nil)
	  (setq best-value most-positive-fixnum)
	  (while sub
	    (when (and (numberp (window-new-normal sub))
		       (< (window-new-normal sub) best-value))
	      (setq best-window sub)
	      (setq best-value (window-new-normal sub)))

	    (setq sub (window-right sub)))

	  (when best-window
	    (setq delta (1- delta)))
	  (set-window-new-total best-window 1 t)
	  (set-window-new-normal
	   best-window
	   (- (/ (float (window-new-total best-window))
		 parent-total)
	      (window-normal-size best-window horizontal))))))

      (when best-window
	(setq sub first)
	(while sub
	  (when (or (consp (window-new-normal sub))
		    (numberp (window-new-normal sub)))
1785
	    ;; Reset new normal size fields so `window-resize-apply'
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	    ;; won't use them to apply new sizes.
	    (set-window-new-normal sub))

	  (unless (eq (window-new-normal sub) 'ignore)
	    ;; Resize this subwindow's subwindows (back-engineering
	    ;; delta from sub's old and new total sizes).
	    (let ((delta (- (window-new-total sub)
			    (window-total-size sub horizontal))))
	      (unless (and (zerop delta) (not trail))
		;; For the TRAIL non-nil case we have to resize SUB
		;; recursively even if it's size does not change.
1797
		(window--resize-this-window
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		 sub delta horizontal ignore nil trail edge))))
	  (setq sub (window-right sub)))))))

1801
(defun window--resize-siblings (window delta &optional horizontal ignore trail edge)
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