/
window.el
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window.el
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;;; window.el --- GNU Emacs window commands aside from those written in C
;; Copyright (C) 1985, 1989, 1992, 1993, 1994, 2000, 2001, 2002,
;; 2003, 2004, 2005, 2006, 2007, 2008, 2009
;; Free Software Foundation, Inc.
;; Maintainer: FSF
;; Keywords: internal
;; 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))
(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 you explicitly change the size, or Emacs has no other choice.")
(make-variable-buffer-local 'window-size-fixed)
(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)."
`(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))))))
(defun window-body-height (&optional window)
"Return number of lines in WINDOW available for actual buffer text.
WINDOW defaults to the selected window.
The return value does not include the mode line or the 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."
(or window (setq window (selected-window)))
(if (window-minibuffer-p window)
(window-height window)
(with-current-buffer (window-buffer window)
(max 1 (- (window-height window)
(if mode-line-format 1 0)
(if header-line-format 1 0))))))
;; See discussion in bug#4543.
(defun window-full-height-p (&optional window)
"Return non-nil if WINDOW is not the result of a vertical split.
WINDOW defaults to the selected window. (This function is not
appropriate for minibuffers.)"
(unless window
(setq window (selected-window)))
(= (window-height window)
(window-height (frame-root-window (window-frame window)))))
(defun one-window-p (&optional nomini all-frames)
"Return non-nil if the selected window is the only window.
Optional arg NOMINI non-nil means don't count the minibuffer
even if it is active. Otherwise, the minibuffer is counted
when it is active.
The optional arg ALL-FRAMES t means count windows on all frames.
If it is `visible', count windows on all visible frames.
ALL-FRAMES nil or omitted means count only the selected frame,
plus the minibuffer it uses (which may be on another frame).
ALL-FRAMES 0 means count all windows in all visible or iconified frames.
If ALL-FRAMES is anything else, count only the selected frame."
(let ((base-window (selected-window)))
(if (and nomini (eq base-window (minibuffer-window)))
(setq base-window (next-window base-window)))
(eq base-window
(next-window base-window (if nomini 'arg) all-frames))))
(defun window-current-scroll-bars (&optional window)
"Return the current scroll bar settings for WINDOW.
WINDOW defaults to the selected window.
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."
(let ((vert (nth 2 (window-scroll-bars window)))
(hor nil))
(when (or (eq vert t) (eq hor t))
(let ((fcsb (frame-current-scroll-bars
(window-frame (or window (selected-window))))))
(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)
"Cycle through all windows, calling PROC for each one.
PROC must specify a function with a window as its sole argument.
The optional arguments MINIBUF and ALL-FRAMES specify the set of
windows to include in the walk, see also `next-window'.
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.
Several frames may share a single minibuffer; if the minibuffer
is active, all windows on all frames that share that minibuffer
are included too. Therefore, if you are using a separate
minibuffer frame and the minibuffer is active and MINIBUF says it
counts, `walk-windows' includes the windows in the frame from
which you entered the minibuffer, as well as the minibuffer
window.
ALL-FRAMES nil or omitted means cycle through all windows on
WINDOW's frame, plus the minibuffer window if specified by the
MINIBUF argument, see above. If the minibuffer counts, cycle
through all windows on all frames that share that minibuffer
too.
ALL-FRAMES t means cycle through all windows on all existing
frames.
ALL-FRAMES `visible' means cycle through all windows on all
visible frames.
ALL-FRAMES 0 means cycle through all windows on all visible and
iconified frames.
ALL-FRAMES a frame means cycle through all windows on that frame
only.
Anything else means cycle through all windows on WINDOW's frame
and no others.
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))
(let* (walk-windows-already-seen
(walk-windows-current (selected-window)))
(while (progn
(setq walk-windows-current
(next-window walk-windows-current minibuf all-frames))
(not (memq walk-windows-current walk-windows-already-seen)))
(setq walk-windows-already-seen
(cons walk-windows-current walk-windows-already-seen))
(funcall proc walk-windows-current)))))
(defun get-window-with-predicate (predicate &optional minibuf
all-frames default)
"Return a window satisfying PREDICATE.
More precisely, cycle through all windows using `walk-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 non-nil. If no window satisfies PREDICATE,
return DEFAULT.
The optional arguments MINIBUF and ALL-FRAMES specify the set of
windows to include. See `walk-windows' for the meaning of these
arguments."
(catch 'found
(walk-windows #'(lambda (window)
(when (funcall predicate window)
(throw 'found window)))
minibuf all-frames)
default))
(defalias 'some-window 'get-window-with-predicate)
;; This should probably be written in C (i.e., without using `walk-windows').
(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
and defaults to the current buffer.
The optional arguments MINIBUF and ALL-FRAMES specify the set of
windows to consider. See `walk-windows' for the precise meaning
of these arguments."
(let ((buffer (cond
((not buffer-or-name) (current-buffer))
((bufferp buffer-or-name) buffer-or-name)
(t (get-buffer buffer-or-name))))
windows)
(walk-windows (function (lambda (window)
(if (eq (window-buffer window) buffer)
(setq windows (cons window windows)))))
minibuf all-frames)
windows))
(defun minibuffer-window-active-p (window)
"Return t if WINDOW is the currently active minibuffer window."
(eq window (active-minibuffer-window)))
(defun count-windows (&optional minibuf)
"Return the number of visible windows.
The optional argument MINIBUF specifies whether the minibuffer
window shall be counted. See `walk-windows' for the precise
meaning of this argument."
(let ((count 0))
(walk-windows (lambda (w) (setq count (+ count 1)))
minibuf)
count))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; `balance-windows' subroutines using `window-tree'
;;; Translate from internal window tree format
(defun bw-get-tree (&optional window-or-frame)
"Get a window split tree in our format.
WINDOW-OR-FRAME must be nil, a frame, or a window. If it is nil,
then the whole window split tree for `selected-frame' is returned.
If it is a frame, then this is used instead. If it is a window,
then the smallest tree containing that window is returned."
(when window-or-frame
(unless (or (framep window-or-frame)
(windowp window-or-frame))
(error "Not a frame or window: %s" window-or-frame)))
(let ((subtree (bw-find-tree-sub window-or-frame)))
(when subtree
(if (integerp subtree)
nil
(bw-get-tree-1 subtree)))))
(defun bw-get-tree-1 (split)
(if (windowp split)
split
(let ((dir (car split))
(edges (car (cdr split)))
(childs (cdr (cdr split))))
(list
(cons 'dir (if dir 'ver 'hor))
(cons 'b (nth 3 edges))
(cons 'r (nth 2 edges))
(cons 't (nth 1 edges))
(cons 'l (nth 0 edges))
(cons 'childs (mapcar #'bw-get-tree-1 childs))))))
(defun bw-find-tree-sub (window-or-frame &optional get-parent)
(let* ((window (when (windowp window-or-frame) window-or-frame))
(frame (when (windowp window) (window-frame window)))
(wt (car (window-tree frame))))
(when (< 1 (length (window-list frame 0)))
(if window
(bw-find-tree-sub-1 wt window get-parent)
wt))))
(defun bw-find-tree-sub-1 (tree win &optional get-parent)
(unless (windowp win) (error "Not a window: %s" win))
(if (memq win tree)
(if get-parent
get-parent
tree)
(let ((childs (cdr (cdr tree)))
child
subtree)
(while (and childs (not subtree))
(setq child (car childs))
(setq childs (cdr childs))
(when (and child (listp child))
(setq subtree (bw-find-tree-sub-1 child win get-parent))))
(if (integerp subtree)
(progn
(if (= 1 subtree)
tree
(1- subtree)))
subtree
))))
;;; Window or object edges
(defun bw-l (obj)
"Left edge of OBJ."
(if (windowp obj) (nth 0 (window-edges obj)) (cdr (assq 'l obj))))
(defun bw-t (obj)
"Top edge of OBJ."
(if (windowp obj) (nth 1 (window-edges obj)) (cdr (assq 't obj))))
(defun bw-r (obj)
"Right edge of OBJ."
(if (windowp obj) (nth 2 (window-edges obj)) (cdr (assq 'r obj))))
(defun bw-b (obj)
"Bottom edge of OBJ."
(if (windowp obj) (nth 3 (window-edges obj)) (cdr (assq 'b obj))))
;;; Split directions
(defun bw-dir (obj)
"Return window split tree direction if OBJ.
If OBJ is a window return 'both. If it is a window split tree
then return its direction."
(if (symbolp obj)
obj
(if (windowp obj)
'both
(let ((dir (cdr (assq 'dir obj))))
(unless (memq dir '(hor ver both))
(error "Can't find dir in %s" obj))
dir))))
(defun bw-eqdir (obj1 obj2)
"Return t if window split tree directions are equal.
OBJ1 and OBJ2 should be either windows or window split trees in
our format. The directions returned by `bw-dir' are compared and
t is returned if they are `eq' or one of them is 'both."
(let ((dir1 (bw-dir obj1))
(dir2 (bw-dir obj2)))
(or (eq dir1 dir2)
(eq dir1 'both)
(eq dir2 'both))))
;;; Building split tree
(defun bw-refresh-edges (obj)
"Refresh the edge information of OBJ and return OBJ."
(unless (windowp obj)
(let ((childs (cdr (assq 'childs obj)))
(ol 1000)
(ot 1000)
(or -1)
(ob -1))
(dolist (o childs)
(when (> ol (bw-l o)) (setq ol (bw-l o)))
(when (> ot (bw-t o)) (setq ot (bw-t o)))
(when (< or (bw-r o)) (setq or (bw-r o)))
(when (< ob (bw-b o)) (setq ob (bw-b o))))
(setq obj (delq 'l obj))
(setq obj (delq 't obj))
(setq obj (delq 'r obj))
(setq obj (delq 'b obj))
(add-to-list 'obj (cons 'l ol))
(add-to-list 'obj (cons 't ot))
(add-to-list 'obj (cons 'r or))
(add-to-list 'obj (cons 'b ob))
))
obj)
;;; Balance windows
(defun balance-windows (&optional window-or-frame)
"Make windows the same heights or widths in window split subtrees.
When called non-interactively WINDOW-OR-FRAME may be either a
window or a frame. It then balances the windows on the implied
frame. If the parameter is a window only the corresponding window
subtree is balanced."
(interactive)
(let (
(wt (bw-get-tree window-or-frame))
(w)
(h)
(tried-sizes)
(last-sizes)
(windows (window-list nil 0)))
(when wt
(while (not (member last-sizes tried-sizes))
(when last-sizes (setq tried-sizes (cons last-sizes tried-sizes)))
(setq last-sizes (mapcar (lambda (w)
(window-edges w))
windows))
(when (eq 'hor (bw-dir wt))
(setq w (- (bw-r wt) (bw-l wt))))
(when (eq 'ver (bw-dir wt))
(setq h (- (bw-b wt) (bw-t wt))))
(bw-balance-sub wt w h)))))
(defun bw-adjust-window (window delta horizontal)
"Wrapper around `adjust-window-trailing-edge' with error checking.
Arguments WINDOW, DELTA and HORIZONTAL are passed on to that function."
;; `adjust-window-trailing-edge' may fail if delta is too large.
(while (>= (abs delta) 1)
(condition-case err
(progn
(adjust-window-trailing-edge window delta horizontal)
(setq delta 0))
(error
;;(message "adjust: %s" (error-message-string err))
(setq delta (/ delta 2))))))
(defun bw-balance-sub (wt w h)
(setq wt (bw-refresh-edges wt))
(unless w (setq w (- (bw-r wt) (bw-l wt))))
(unless h (setq h (- (bw-b wt) (bw-t wt))))
(if (windowp wt)
(progn
(when w
(let ((dw (- w (- (bw-r wt) (bw-l wt)))))
(when (/= 0 dw)
(bw-adjust-window wt dw t))))
(when h
(let ((dh (- h (- (bw-b wt) (bw-t wt)))))
(when (/= 0 dh)
(bw-adjust-window wt dh nil)))))
(let* ((childs (cdr (assq 'childs wt)))
(cw (when w (/ w (if (bw-eqdir 'hor wt) (length childs) 1))))
(ch (when h (/ h (if (bw-eqdir 'ver wt) (length childs) 1)))))
(dolist (c childs)
(bw-balance-sub c cw ch)))))
(defun window-fixed-size-p (&optional window direction)
"Return t if WINDOW cannot be resized in DIRECTION.
WINDOW defaults to the selected window. DIRECTION can be
nil (i.e. any), `height' or `width'."
(with-current-buffer (window-buffer window)
(when (and (boundp 'window-size-fixed) window-size-fixed)
(not (and direction
(member (cons direction window-size-fixed)
'((height . width) (width . height))))))))
;;; A different solution to balance-windows.
(defvar window-area-factor 1
"Factor by which the window area should be over-estimated.
This is used by `balance-windows-area'.
Changing this globally has no effect.")
(make-variable-buffer-local 'window-area-factor)
(defun balance-windows-area ()
"Make all visible windows the same area (approximately).
See also `window-area-factor' to change the relative size of
specific buffers."
(interactive)
(let* ((unchanged 0) (carry 0) (round 0)
;; Remove fixed-size windows.
(wins (delq nil (mapcar (lambda (win)
(if (not (window-fixed-size-p win)) win))
(window-list nil 'nomini))))
(changelog nil)
next)
;; Resizing a window changes the size of surrounding windows in complex
;; ways, so it's difficult to balance them all. The introduction of
;; `adjust-window-trailing-edge' made it a bit easier, but it is still
;; very difficult to do. `balance-window' above takes an off-line
;; approach: get the whole window tree, then balance it, then try to
;; adjust the windows so they fit the result.
;; Here, instead, we take a "local optimization" approach, where we just
;; go through all the windows several times until nothing needs to be
;; changed. The main problem with this approach is that it's difficult
;; to make sure it terminates, so we use some heuristic to try and break
;; off infinite loops.
;; After a round without any change, we allow a second, to give a chance
;; to the carry to propagate a minor imbalance from the end back to
;; the beginning.
(while (< unchanged 2)
;; (message "New round")
(setq unchanged (1+ unchanged) round (1+ round))
(dolist (win wins)
(setq next win)
(while (progn (setq next (next-window next))
(window-fixed-size-p next)))
;; (assert (eq next (or (cadr (member win wins)) (car wins))))
(let* ((horiz
(< (car (window-edges win)) (car (window-edges next))))
(areadiff (/ (- (* (window-height next) (window-width next)
(buffer-local-value 'window-area-factor
(window-buffer next)))
(* (window-height win) (window-width win)
(buffer-local-value 'window-area-factor
(window-buffer win))))
(max (buffer-local-value 'window-area-factor
(window-buffer win))
(buffer-local-value 'window-area-factor
(window-buffer next)))))
(edgesize (if horiz
(+ (window-height win) (window-height next))
(+ (window-width win) (window-width next))))
(diff (/ areadiff edgesize)))
(when (zerop diff)
;; Maybe diff is actually closer to 1 than to 0.
(setq diff (/ (* 3 areadiff) (* 2 edgesize))))
(when (and (zerop diff) (not (zerop areadiff)))
(setq diff (/ (+ areadiff carry) edgesize))
;; Change things smoothly.
(if (or (> diff 1) (< diff -1)) (setq diff (/ diff 2))))
(if (zerop diff)
;; Make sure negligible differences don't accumulate to
;; become significant.
(setq carry (+ carry areadiff))
(bw-adjust-window win diff horiz)
;; (sit-for 0.5)
(let ((change (cons win (window-edges win))))
;; If the same change has been seen already for this window,
;; we're most likely in an endless loop, so don't count it as
;; a change.
(unless (member change changelog)
(push change changelog)
(setq unchanged 0 carry 0)))))))
;; We've now basically balanced all the windows.
;; But there may be some minor off-by-one imbalance left over,
;; so let's do some fine tuning.
;; (bw-finetune wins)
;; (message "Done in %d rounds" round)
))
(defcustom display-buffer-function nil
"If non-nil, function to call to handle `display-buffer'.
It will receive two args, the buffer and a flag which if non-nil
means that the currently selected window is not acceptable. It
should choose or create a window, display the specified buffer in
it, and return the window.
Commands such as `switch-to-buffer-other-window' and
`find-file-other-window' work using this function."
:type '(choice
(const nil)
(function :tag "function"))
:group 'windows)
(defcustom special-display-buffer-names nil
"List of names of buffers that should be displayed specially.
Displaying a buffer with `display-buffer' or `pop-to-buffer', if
its name is in this list, displays the buffer in a way specified
by `special-display-function'. `special-display-popup-frame'
\(the default for `special-display-function') usually displays
the buffer in a separate frame made with the parameters specified
by `special-display-frame-alist'. If `special-display-function'
has been set to some other function, that function is called with
the buffer as first, and nil as second argument.
Alternatively, an element of this list can be specified as
\(BUFFER-NAME FRAME-PARAMETERS), where BUFFER-NAME is a buffer
name and FRAME-PARAMETERS an alist of \(PARAMETER . VALUE) pairs.
`special-display-popup-frame' will interpret such pairs as frame
parameters when it creates a special frame, overriding the
corresponding values from `special-display-frame-alist'.
As a special case, if FRAME-PARAMETERS contains (same-window . t)
`special-display-popup-frame' displays that buffer in the
selected window. If FRAME-PARAMETERS contains (same-frame . t),
it displays that buffer in a window on the selected frame.
If `special-display-function' specifies some other function than
`special-display-popup-frame', that function is called with the
buffer named BUFFER-NAME as first, and FRAME-PARAMETERS as second
argument.
Finally, an element of this list can be also specified as
\(BUFFER-NAME FUNCTION OTHER-ARGS). In that case,
`special-display-popup-frame' will call FUNCTION with the buffer
named BUFFER-NAME as first argument, and OTHER-ARGS as the
second. If `special-display-function' specifies some other
function, that function is called with the buffer named
BUFFER-NAME as first, and the element's cdr as second argument.
If this variable appears \"not to work\", because you added a
name to it but the corresponding buffer is displayed in the
selected window, look at the values of `same-window-buffer-names'
and `same-window-regexps'. Those variables take precedence over
this one.
See also `special-display-regexps'."
:type '(repeat
(choice :tag "Buffer"
:value ""
(string :format "%v")
(cons :tag "With parameters"
:format "%v"
:value ("" . nil)
(string :format "%v")
(repeat :tag "Parameters"
(cons :format "%v"
(symbol :tag "Parameter")
(sexp :tag "Value"))))
(list :tag "With function"
:format "%v"
:value ("" . nil)
(string :format "%v")
(function :tag "Function")
(repeat :tag "Arguments" (sexp)))))
:group 'windows
:group 'frames)
;;;###autoload
(put 'special-display-buffer-names 'risky-local-variable t)
(defcustom special-display-regexps nil
"List of regexps saying which buffers should be displayed specially.
Displaying a buffer with `display-buffer' or `pop-to-buffer', if
any regexp in this list matches its name, displays it specially
using `special-display-function'. `special-display-popup-frame'
\(the default for `special-display-function') usually displays
the buffer in a separate frame made with the parameters specified
by `special-display-frame-alist'. If `special-display-function'
has been set to some other function, that function is called with
the buffer as first, and nil as second argument.
Alternatively, an element of this list can be specified as
\(REGEXP FRAME-PARAMETERS), where REGEXP is a regexp as above and
FRAME-PARAMETERS an alist of (PARAMETER . VALUE) pairs.
`special-display-popup-frame' will then interpret these pairs as
frame parameters when creating a special frame for a buffer whose
name matches REGEXP, overriding the corresponding values from
`special-display-frame-alist'.
As a special case, if FRAME-PARAMETERS contains (same-window . t)
`special-display-popup-frame' displays buffers matching REGEXP in
the selected window. \(same-frame . t) in FRAME-PARAMETERS means
to display such buffers in a window on the selected frame.
If `special-display-function' specifies some other function than
`special-display-popup-frame', that function is called with the
buffer whose name matched REGEXP as first, and FRAME-PARAMETERS
as second argument.
Finally, an element of this list can be also specified as
\(REGEXP FUNCTION OTHER-ARGS). `special-display-popup-frame'
will then call FUNCTION with the buffer whose name matched
REGEXP as first, and OTHER-ARGS as second argument. If
`special-display-function' specifies some other function, that
function is called with the buffer whose name matched REGEXP
as first, and the element's cdr as second argument.
If this variable appears \"not to work\", because you added a
name to it but the corresponding buffer is displayed in the
selected window, look at the values of `same-window-buffer-names'
and `same-window-regexps'. Those variables take precedence over
this one.
See also `special-display-buffer-names'."
:type '(repeat
(choice :tag "Buffer"
:value ""
(regexp :format "%v")
(cons :tag "With parameters"
:format "%v"
:value ("" . nil)
(regexp :format "%v")
(repeat :tag "Parameters"
(cons :format "%v"
(symbol :tag "Parameter")
(sexp :tag "Value"))))
(list :tag "With function"
:format "%v"
:value ("" . nil)
(regexp :format "%v")
(function :tag "Function")
(repeat :tag "Arguments" (sexp)))))
:group 'windows
:group 'frames)
(defun special-display-p (buffer-name)
"Return non-nil if a buffer named BUFFER-NAME gets a special frame.
More precisely, return t if `special-display-buffer-names' or
`special-display-regexps' contain a string entry equaling or
matching BUFFER-NAME. If `special-display-buffer-names' or
`special-display-regexps' contain a list entry whose car equals
or matches BUFFER-NAME, the return value is the cdr of that
entry."
(let (tmp)
(cond
((not (stringp buffer-name)))
((member buffer-name special-display-buffer-names)
t)
((setq tmp (assoc buffer-name special-display-buffer-names))
(cdr tmp))
((catch 'found
(dolist (regexp special-display-regexps)
(cond
((stringp regexp)
(when (string-match-p regexp buffer-name)
(throw 'found t)))
((and (consp regexp) (stringp (car regexp))
(string-match-p (car regexp) buffer-name))
(throw 'found (cdr regexp))))))))))
(defcustom special-display-function 'special-display-popup-frame
"Function to call for displaying special buffers.
This function is called with two arguments - the buffer and,
optionally, a list - and should return a window displaying that
buffer. The default value usually makes a separate frame for the
buffer using `special-display-frame-alist' to specify the frame
parameters. See the definition of `special-display-popup-frame'
for how to specify such a function.
A buffer is special when its name is either listed in
`special-display-buffer-names' or matches a regexp in
`special-display-regexps'."
:type 'function
:group 'frames)
(defcustom same-window-buffer-names nil
"List of names of buffers that should appear in the \"same\" window.
`display-buffer' and `pop-to-buffer' show a buffer whose name is
on this list in the selected rather than some other window.
An element of this list can be a cons cell instead of just a
string. In that case, the cell's car must be a string specifying
the buffer name. This is for compatibility with
`special-display-buffer-names'; the cdr of the cons cell is
ignored.
See also `same-window-regexps'."
:type '(repeat (string :format "%v"))
:group 'windows)
(defcustom same-window-regexps nil
"List of regexps saying which buffers should appear in the \"same\" window.
`display-buffer' and `pop-to-buffer' show a buffer whose name
matches a regexp on this list in the selected rather than some
other window.
An element of this list can be a cons cell instead of just a
string. In that case, the cell's car must be a regexp matching
the buffer name. This is for compatibility with
`special-display-regexps'; the cdr of the cons cell is ignored.
See also `same-window-buffer-names'."
:type '(repeat (regexp :format "%v"))
:group 'windows)
(defun same-window-p (buffer-name)
"Return non-nil if a buffer named BUFFER-NAME would be shown in the \"same\" window.
This function returns non-nil if `display-buffer' or
`pop-to-buffer' would show a buffer named BUFFER-NAME in the
selected rather than \(as usual\) some other window. See
`same-window-buffer-names' and `same-window-regexps'."
(cond
((not (stringp buffer-name)))
;; The elements of `same-window-buffer-names' can be buffer
;; names or cons cells whose cars are buffer names.
((member buffer-name same-window-buffer-names))
((assoc buffer-name same-window-buffer-names))
((catch 'found
(dolist (regexp same-window-regexps)
;; The elements of `same-window-regexps' can be regexps
;; or cons cells whose cars are regexps.
(when (or (and (stringp regexp)
(string-match regexp buffer-name))
(and (consp regexp) (stringp (car regexp))
(string-match-p (car regexp) buffer-name)))
(throw 'found t)))))))
(defcustom pop-up-frames nil
"Whether `display-buffer' should make a separate frame.
If nil, never make a seperate frame.
If the value is `graphic-only', make a separate frame
on graphic displays only.
Any other non-nil value means always make a separate frame."
:type '(choice
(const :tag "Never" nil)
(const :tag "On graphic displays only" graphic-only)
(const :tag "Always" t))
:group 'windows)
(defcustom display-buffer-reuse-frames nil
"Non-nil means `display-buffer' should reuse frames.
If the buffer in question is already displayed in a frame, raise
that frame."
:type 'boolean
:version "21.1"
:group 'windows)
(defcustom pop-up-windows t
"Non-nil means `display-buffer' should make a new window."
:type 'boolean
:group 'windows)
(defcustom split-window-preferred-function 'split-window-sensibly
"Function called by `display-buffer' routines to split a window.
This function is called with a window as single argument and is
supposed to split that window and return the new window. If the
window can (or shall) not be split, it is supposed to return nil.
The default is to call the function `split-window-sensibly' which
tries to split the window in a way which seems most suitable.
You can customize the options `split-height-threshold' and/or
`split-width-threshold' in order to have `split-window-sensibly'
prefer either vertical or horizontal splitting.
If you set this to any other function, bear in mind that the
`display-buffer' routines may call this function two times. The
argument of the first call is the largest window on its frame.
If that call fails to return a live window, the function is
called again with the least recently used window as argument. If
that call fails too, `display-buffer' will use an existing window
to display its buffer.
The window selected at the time `display-buffer' was invoked is
still selected when this function is called. Hence you can
compare the window argument with the value of `selected-window'
if you intend to split the selected window instead or if you do
not want to split the selected window."
:type 'function
:version "23.1"
:group 'windows)
(defcustom split-height-threshold 80
"Minimum height for splitting windows sensibly.
If this is an integer, `split-window-sensibly' may split a window
vertically only if it has at least this many lines. If this is
nil, `split-window-sensibly' is not allowed to split a window
vertically. If, however, a window is the only window on its
frame, `split-window-sensibly' may split it vertically
disregarding the value of this variable."
:type '(choice (const nil) (integer :tag "lines"))
:version "23.1"
:group 'windows)
(defcustom split-width-threshold 160
"Minimum width for splitting windows sensibly.
If this is an integer, `split-window-sensibly' may split a window
horizontally only if it has at least this many columns. If this
is nil, `split-window-sensibly' is not allowed to split a window
horizontally."
:type '(choice (const nil) (integer :tag "columns"))
:version "23.1"
:group 'windows)
(defun window-splittable-p (window &optional horizontal)
"Return non-nil if `split-window-sensibly' may split WINDOW.
Optional argument HORIZONTAL nil or omitted means check whether
`split-window-sensibly' may split WINDOW vertically. HORIZONTAL
non-nil means check whether WINDOW may be split horizontally.
WINDOW may be split vertically when the following conditions
hold:
- `window-size-fixed' is either nil or equals `width' for the
buffer of WINDOW.
- `split-height-threshold' is an integer and WINDOW is at least as
high as `split-height-threshold'.
- When WINDOW is split evenly, the emanating windows are at least
`window-min-height' lines tall and can accommodate at least one
line plus - if WINDOW has one - a mode line.
WINDOW may be split horizontally when the following conditions
hold:
- `window-size-fixed' is either nil or equals `height' for the
buffer of WINDOW.
- `split-width-threshold' is an integer and WINDOW is at least as
wide as `split-width-threshold'.
- When WINDOW is split evenly, the emanating windows are at least
`window-min-width' or two (whichever is larger) columns wide."
(when (window-live-p window)
(with-current-buffer (window-buffer window)
(if horizontal
;; A window can be split horizontally when its width is not
;; fixed, it is at least `split-width-threshold' columns wide
;; and at least twice as wide as `window-min-width' and 2 (the
;; latter value is hardcoded).
(and (memq window-size-fixed '(nil height))
;; Testing `window-full-width-p' here hardly makes any
;; sense nowadays. This can be done more intuitively by
;; setting up `split-width-threshold' appropriately.
(numberp split-width-threshold)
(>= (window-width window)
(max split-width-threshold
(* 2 (max window-min-width 2)))))
;; A window can be split vertically when its height is not
;; fixed, it is at least `split-height-threshold' lines high,
;; and it is at least twice as high as `window-min-height' and 2
;; if it has a modeline or 1.
(and (memq window-size-fixed '(nil width))
(numberp split-height-threshold)
(>= (window-height window)
(max split-height-threshold
(* 2 (max window-min-height
(if mode-line-format 2 1))))))))))
(defun split-window-sensibly (window)
"Split WINDOW in a way suitable for `display-buffer'.
If `split-height-threshold' specifies an integer, WINDOW is at
least `split-height-threshold' lines tall and can be split
vertically, split WINDOW into two windows one above the other and
return the lower window. Otherwise, if `split-width-threshold'
specifies an integer, WINDOW is at least `split-width-threshold'
columns wide and can be split horizontally, split WINDOW into two
windows side by side and return the window on the right. If this
can't be done either and WINDOW is the only window on its frame,
try to split WINDOW vertically disregarding any value specified
by `split-height-threshold'. If that succeeds, return the lower
window. Return nil otherwise.
By default `display-buffer' routines call this function to split
the largest or least recently used window. To change the default
customize the option `split-window-preferred-function'.
You can enforce this function to not split WINDOW horizontally,
by setting \(or binding) the variable `split-width-threshold' to
nil. If, in addition, you set `split-height-threshold' to zero,
chances increase that this function does split WINDOW vertically.
In order to not split WINDOW vertically, set \(or bind) the
variable `split-height-threshold' to nil. Additionally, you can
set `split-width-threshold' to zero to make a horizontal split
more likely to occur.
Have a look at the function `window-splittable-p' if you want to
know how `split-window-sensibly' determines whether WINDOW can be
split."
(or (and (window-splittable-p window)
;; Split window vertically.
(with-selected-window window
(split-window-vertically)))
(and (window-splittable-p window t)
;; Split window horizontally.
(with-selected-window window
(split-window-horizontally)))
(and (eq window (frame-root-window (window-frame window)))
(not (window-minibuffer-p window))
;; If WINDOW is the only window on its frame and is not the
;; minibuffer window, try to split it vertically disregarding
;; the value of `split-height-threshold'.
(let ((split-height-threshold 0))
(when (window-splittable-p window)
(with-selected-window window
(split-window-vertically)))))))
(defun window--try-to-split-window (window)
"Try to split WINDOW.
Return value returned by `split-window-preferred-function' if it
represents a live window, nil otherwise."
(and (window-live-p window)
(not (frame-parameter (window-frame window) 'unsplittable))
(let ((new-window
;; Since `split-window-preferred-function' might
;; throw an error use `condition-case'.
(condition-case nil
(funcall split-window-preferred-function window)
(error nil))))
(and (window-live-p new-window) new-window))))
(defun window--frame-usable-p (frame)
"Return FRAME if it can be used to display a buffer."
(when (frame-live-p frame)
(let ((window (frame-root-window frame)))
;; `frame-root-window' may be an internal window which is considered
;; "dead" by `window-live-p'. Hence if `window' is not live we
;; implicitly know that `frame' has a visible window we can use.
(unless (and (window-live-p window)
(or (window-minibuffer-p window)
;; If the window is soft-dedicated, the frame is usable.
;; Actually, even if the window is really dedicated,
;; the frame is still usable by splitting it.
;; At least Emacs-22 allowed it, and it is desirable
;; when displaying same-frame windows.
nil ; (eq t (window-dedicated-p window))
))
frame))))
(defcustom even-window-heights t
"If non-nil `display-buffer' will try to even window heights.
Otherwise `display-buffer' will leave the window configuration
alone. Heights are evened only when `display-buffer' chooses a
window that appears above or below the selected window."
:type 'boolean
:group 'windows)
(defun window--even-window-heights (window)