window.el 64.6 KB
Newer Older
1
;;; window.el --- GNU Emacs window commands aside from those written in C
Eric S. Raymond's avatar
Eric S. Raymond committed
2

3
;; Copyright (C) 1985, 1989, 1992, 1993, 1994, 2000, 2001, 2002,
Glenn Morris's avatar
Glenn Morris committed
4
;;   2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
Joseph Arceneaux's avatar
Joseph Arceneaux committed
5

Eric S. Raymond's avatar
Eric S. Raymond committed
6
;; Maintainer: FSF
Gerd Moellmann's avatar
Gerd Moellmann committed
7
;; Keywords: internal
Eric S. Raymond's avatar
Eric S. Raymond committed
8

Joseph Arceneaux's avatar
Joseph Arceneaux committed
9 10
;; This file is part of GNU Emacs.

11
;; GNU Emacs is free software: you can redistribute it and/or modify
Joseph Arceneaux's avatar
Joseph Arceneaux committed
12
;; it under the terms of the GNU General Public License as published by
13 14
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
Joseph Arceneaux's avatar
Joseph Arceneaux committed
15 16 17 18 19 20 21

;; 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
22
;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
Joseph Arceneaux's avatar
Joseph Arceneaux committed
23

24 25 26 27 28
;;; Commentary:

;; Window tree functions.

;;; Code:
29

Andreas Schwab's avatar
Andreas Schwab committed
30 31
(eval-when-compile (require 'cl))

32 33
(defvar window-size-fixed nil
 "*Non-nil in a buffer means windows displaying the buffer are fixed-size.
34
If the value is `height', then only the window's height is fixed.
35 36 37 38 39 40
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)

41 42
(defmacro save-selected-window (&rest body)
  "Execute BODY, then select the window that was selected before BODY.
43 44 45 46
The value returned is the value of the last form in BODY.

This macro saves and restores the current buffer, since otherwise
its normal operation could potentially make a different
Richard M. Stallman's avatar
Richard M. Stallman committed
47
buffer current.  It does not alter the buffer list ordering.
48 49 50 51 52 53 54

This macro saves and restores the selected window, as well as
the selected window in each frame.  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.  If the selected window is
no longer live, then whatever window is selected at the end of
BODY remains selected."
55
  `(let ((save-selected-window-window (selected-window))
Richard M. Stallman's avatar
Richard M. Stallman committed
56 57 58
	 ;; It is necessary to save all of these, because calling
	 ;; select-window changes frame-selected-window for whatever
	 ;; frame that window is in.
59
	 (save-selected-window-alist
60
	  (mapcar (lambda (frame) (cons frame (frame-selected-window frame)))
61
		  (frame-list))))
62 63 64 65 66
     (save-current-buffer
       (unwind-protect
	   (progn ,@body)
	 (dolist (elt save-selected-window-alist)
	   (and (frame-live-p (car elt))
67 68
		(window-live-p (cdr elt))
		(set-frame-selected-window (car elt) (cdr elt))))
69 70
	 (if (window-live-p save-selected-window-window)
	     (select-window save-selected-window-window))))))
71

72 73 74 75
(defun window-body-height (&optional window)
  "Return number of lines in window WINDOW for actual buffer text.
This does not include the mode line (if any) or the header line (if any)."
  (or window (setq window (selected-window)))
76 77 78 79 80 81
  (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))))))
82

83
(defun one-window-p (&optional nomini all-frames)
84
  "Return non-nil if the selected window is the only window.
85
Optional arg NOMINI non-nil means don't count the minibuffer
86 87
even if it is active.  Otherwise, the minibuffer is counted
when it is active.
88 89 90

The optional arg ALL-FRAMES t means count windows on all frames.
If it is `visible', count windows on all visible frames.
91
ALL-FRAMES nil or omitted means count only the selected frame,
92
plus the minibuffer it uses (which may be on another frame).
93 94
ALL-FRAMES 0 means count all windows in all visible or iconified frames.
If ALL-FRAMES is anything else, count only the selected frame."
95 96 97 98 99 100
  (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))))

101 102
(defun window-current-scroll-bars (&optional window)
  "Return the current scroll-bar settings in window WINDOW.
103
Value is a cons (VERTICAL . HORIZONTAL) where VERTICAL specifies the
104
current location of the vertical scroll-bars (left, right, or nil),
105
and HORIZONTAL specifies the current location of the horizontal scroll
106 107 108 109
bars (top, bottom, or nil)."
  (let ((vert (nth 2 (window-scroll-bars window)))
	(hor nil))
    (when (or (eq vert t) (eq hor t))
110
      (let ((fcsb (frame-current-scroll-bars
111 112 113 114 115 116 117
		   (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)))

118 119 120 121 122
(defun walk-windows (proc &optional minibuf all-frames)
  "Cycle through all visible windows, calling PROC for each one.
PROC is called with a window as argument.

Optional second arg MINIBUF t means count the minibuffer window even
123
if not active.  MINIBUF nil or omitted means count the minibuffer only if
124 125 126 127 128
it is active.  MINIBUF neither t nor nil means not to count the
minibuffer even if it is active.

Several frames may share a single minibuffer; if the minibuffer
counts, all windows on all frames that share that minibuffer count
Richard M. Stallman's avatar
Richard M. Stallman committed
129 130
too.  Therefore, if you are using a separate minibuffer frame
and the minibuffer is active and MINIBUF says it counts,
131
`walk-windows' includes the windows in the frame from which you
Richard M. Stallman's avatar
Richard M. Stallman committed
132
entered the minibuffer, as well as the minibuffer window.
133

Richard M. Stallman's avatar
Richard M. Stallman committed
134 135 136
ALL-FRAMES is the optional third argument.
ALL-FRAMES nil or omitted means cycle within the frames as specified above.
ALL-FRAMES = `visible' means include windows on all visible frames.
137
ALL-FRAMES = 0 means include windows on all visible and iconified frames.
Richard M. Stallman's avatar
Richard M. Stallman committed
138
ALL-FRAMES = t means include windows on all frames including invisible frames.
139
If ALL-FRAMES is a frame, it means include windows on that frame.
Richard M. Stallman's avatar
Richard M. Stallman committed
140
Anything else means restrict to the selected frame."
141 142 143
  ;; If we start from the minibuffer window, don't fail to come back to it.
  (if (window-minibuffer-p (selected-window))
      (setq minibuf t))
144 145 146
  (save-selected-window
    (if (framep all-frames)
	(select-window (frame-first-window all-frames)))
Gerd Moellmann's avatar
Gerd Moellmann committed
147 148
    (let* (walk-windows-already-seen
	   (walk-windows-current (selected-window)))
149 150 151
      (while (progn
	       (setq walk-windows-current
		     (next-window walk-windows-current minibuf all-frames))
Gerd Moellmann's avatar
Gerd Moellmann committed
152 153 154 155 156
	       (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)))))

157 158
(defun get-window-with-predicate (predicate &optional minibuf
					    all-frames default)
Gerd Moellmann's avatar
Gerd Moellmann committed
159 160 161 162 163 164 165 166 167
  "Return a window satisfying PREDICATE.

This function cycles through all visible windows using `walk-windows',
calling PREDICATE on each one.  PREDICATE is called with a window as
argument.  The first window for which PREDICATE returns a non-nil
value is returned.  If no window satisfies PREDICATE, DEFAULT is
returned.

Optional second arg MINIBUF t means count the minibuffer window even
168
if not active.  MINIBUF nil or omitted means count the minibuffer only if
Gerd Moellmann's avatar
Gerd Moellmann committed
169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186
it is active.  MINIBUF neither t nor nil means not to count the
minibuffer even if it is active.

Several frames may share a single minibuffer; if the minibuffer
counts, all windows on all frames that share that minibuffer count
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 is the optional third argument.
ALL-FRAMES nil or omitted means cycle within the frames as specified above.
ALL-FRAMES = `visible' means include windows on all visible frames.
ALL-FRAMES = 0 means include windows on all visible and iconified frames.
ALL-FRAMES = t means include windows on all frames including invisible frames.
If ALL-FRAMES is a frame, it means include windows on that frame.
Anything else means restrict to the selected frame."
  (catch 'found
187
    (walk-windows #'(lambda (window)
Gerd Moellmann's avatar
Gerd Moellmann committed
188 189 190 191
		      (when (funcall predicate window)
			(throw 'found window)))
		  minibuf all-frames)
    default))
192

193 194
(defalias 'some-window 'get-window-with-predicate)

195
;; This should probably be written in C (i.e., without using `walk-windows').
196
(defun get-buffer-window-list (buffer &optional minibuf all-frames)
197 198
  "Return list of all windows displaying BUFFER, or nil if none.
BUFFER can be a buffer or a buffer name.
199
See `walk-windows' for the meaning of MINIBUF and ALL-FRAMES."
200 201 202 203
  (let ((buffer (if (bufferp buffer) buffer (get-buffer buffer))) windows)
    (walk-windows (function (lambda (window)
			      (if (eq (window-buffer window) buffer)
				  (setq windows (cons window windows)))))
204
		  minibuf all-frames)
205 206
    windows))

207 208
(defun minibuffer-window-active-p (window)
  "Return t if WINDOW (a minibuffer window) is now active."
209
  (eq window (active-minibuffer-window)))
210

Joseph Arceneaux's avatar
Joseph Arceneaux committed
211
(defun count-windows (&optional minibuf)
212
   "Return the number of visible windows.
213 214 215
This counts the windows in the selected frame and (if the minibuffer is
to be counted) its minibuffer frame (if that's not the same frame).
The optional arg MINIBUF non-nil means count the minibuffer
Karl Heuer's avatar
Karl Heuer committed
216
even if it is inactive."
Joseph Arceneaux's avatar
Joseph Arceneaux committed
217
   (let ((count 0))
218
     (walk-windows (lambda (w) (setq count (+ count 1)))
Joseph Arceneaux's avatar
Joseph Arceneaux committed
219 220 221
		   minibuf)
     count))

222
(defun window-safely-shrinkable-p (&optional window)
223 224
  "Non-nil if the WINDOW can be shrunk without shrinking other windows.
If WINDOW is nil or omitted, it defaults to the currently selected window."
225 226 227 228 229
  (with-selected-window (or window (selected-window))
    (let ((edges (window-edges)))
      (or (= (nth 2 edges) (nth 2 (window-edges (previous-window))))
	  (= (nth 0 edges) (nth 0 (window-edges (next-window))))))))

230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; `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)))
248 249 250 251
    (when subtree
      (if (integerp subtree)
	  nil
	(bw-get-tree-1 subtree)))))
252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299

(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

300
(defun bw-l (obj)
301 302
  "Left edge of OBJ."
  (if (windowp obj) (nth 0 (window-edges obj)) (cdr (assq 'l obj))))
303
(defun bw-t (obj)
304 305
  "Top edge of OBJ."
  (if (windowp obj) (nth 1 (window-edges obj)) (cdr (assq 't obj))))
306
(defun bw-r (obj)
307 308
  "Right edge of OBJ."
  (if (windowp obj) (nth 2 (window-edges obj)) (cdr (assq 'r obj))))
309
(defun bw-b (obj)
310 311 312 313 314
  "Bottom edge of OBJ."
  (if (windowp obj) (nth 3 (window-edges obj)) (cdr (assq 'b obj))))

;;; Split directions

315
(defun bw-dir (obj)
316
  "Return window split tree direction if OBJ.
317
If OBJ is a window return 'both.  If it is a window split tree
318 319 320 321 322 323 324 325 326 327
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))))

328
(defun bw-eqdir (obj1 obj2)
329 330
  "Return t if window split tree directions are equal.
OBJ1 and OBJ2 should be either windows or window split trees in
331
our format.  The directions returned by `bw-dir' are compared and
332 333 334 335 336 337 338 339 340
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

341
(defun bw-refresh-edges (obj)
342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366
  "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

367
(defun balance-windows (&optional window-or-frame)
368 369 370
  "Make windows the same heights or widths in window split subtrees.

When called non-interactively WINDOW-OR-FRAME may be either a
371 372
window or a frame.  It then balances the windows on the implied
frame.  If the parameter is a window only the corresponding window
373
subtree is balanced."
Joseph Arceneaux's avatar
Joseph Arceneaux committed
374
  (interactive)
375 376 377 378 379 380
  (let (
        (wt (bw-get-tree window-or-frame))
        (w)
        (h)
        (tried-sizes)
        (last-sizes)
381
        (windows (window-list nil 0)))
382 383 384
    (when wt
      (while (not (member last-sizes tried-sizes))
        (when last-sizes (setq tried-sizes (cons last-sizes tried-sizes)))
385
        (setq last-sizes (mapcar (lambda (w)
386 387 388 389 390 391 392 393
                                   (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)))))

394
(defun bw-adjust-window (window delta horizontal)
395 396
  "Wrapper around `adjust-window-trailing-edge' with error checking.
Arguments WINDOW, DELTA and HORIZONTAL are passed on to that function."
397 398 399 400 401 402 403 404 405
  ;; `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))))))
406

407
(defun bw-balance-sub (wt w h)
408 409 410 411 412 413 414 415
  (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)
416
              (bw-adjust-window wt dw t))))
417 418 419 420 421 422 423 424
        (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)
425
        (bw-balance-sub c cw ch)))))
426

427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442
;;; A different solution to balance-windows

(defun window-fixed-size-p (&optional window direction)
  "Non-nil if WINDOW cannot be resized in DIRECTION.
DIRECTION can be nil (i.e. any), `height' or `width'."
  (with-current-buffer (window-buffer window)
    (let ((fixed (and (boundp 'window-size-fixed) window-size-fixed)))
      (when fixed
	(not (and direction
		  (member (cons direction window-size-fixed)
			  '((height . width) (width . height)))))))))

(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.")
443
(make-variable-buffer-local 'window-area-factor)
444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520

(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)
    ))

521

522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545
(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)

(defun special-display-p (buffer-name)
  "Return non-nil if a buffer named BUFFER-NAME gets a special frame.
If the value is t, `display-buffer' or `pop-to-buffer' would
create a special frame for that buffer using the default frame
parameters.

If the value is a list, it is a list of frame parameters that
would be used to make a frame for that buffer.  The variables
`special-display-buffer-names' and `special-display-regexps'
control this."
546
  (let (tmp)
547 548 549 550
  (cond
   ((not (stringp buffer-name)))
   ;; Make sure to return t in the following two cases.
   ((member buffer-name special-display-buffer-names) t)
551
     ((setq tmp (assoc buffer-name special-display-buffer-names)) (cdr tmp))
552 553 554 555 556 557 558 559
   ((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))
560
            (throw 'found (cdr regexp))))))))))
561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745

(defcustom special-display-buffer-names nil
  "List of buffer names that should have their own special frames.
Displaying a buffer with `display-buffer' or `pop-to-buffer', if
its name is in this list, makes a special frame for it using
`special-display-function'.  See also `special-display-regexps'.

An element of the list can be a list instead of just a string.
There are two ways to use a list as an element:
  (BUFFER FRAME-PARAMETERS...)  (BUFFER FUNCTION OTHER-ARGS...)
In the first case, the FRAME-PARAMETERS are pairs of the form
\(PARAMETER . VALUE); these parameter values are used to create
the frame.  In the second case, FUNCTION is called with BUFFER as
the first argument, followed by the OTHER-ARGS--it can display
BUFFER in any way it likes.  All this is done by the function
found in `special-display-function'.

If the specified frame parameters include (same-buffer . t), the
buffer is displayed in the currently selected window.  Otherwise, if
they include (same-frame . t), the buffer is displayed in a new window
in the currently selected frame.

If this variable appears \"not to work\", because you add a name to it
but that buffer still appears in the selected window, look at the
values of `same-window-buffer-names' and `same-window-regexps'.
Those variables take precedence over this one."
  :type '(repeat (choice :tag "Buffer"
			 :value ""
			 (string :format "%v")
			 (cons :tag "With attributes"
			       :format "%v"
			       :value ("" . nil)
			       (string :format "%v")
			       (repeat :tag "Attributes"
				       (cons :format "%v"
					     (symbol :tag "Parameter")
					     (sexp :tag "Value"))))))
  :group 'frames)

(defcustom special-display-regexps nil
  "List of regexps saying which buffers should have their own special frames.
When displaying a buffer with `display-buffer' or
`pop-to-buffer', if any regexp in this list matches the buffer
name, it makes a special frame for the buffer by calling
`special-display-function'.

An element of the list can be a list instead of just a string.
There are two ways to use a list as an element:
  (REGEXP FRAME-PARAMETERS...)  (REGEXP FUNCTION OTHER-ARGS...)
In the first case, the FRAME-PARAMETERS are pairs of the form
\(PARAMETER . VALUE); these parameter values are used to create
the frame.  In the second case, FUNCTION is called with BUFFER as
the first argument, followed by the OTHER-ARGS--it can display
the buffer in any way it likes.  All this is done by the function
found in `special-display-function'.

If the specified frame parameters include (same-buffer . t), the
buffer is displayed in the currently selected window.  Otherwise,
if they include (same-frame . t), the buffer is displayed in a
new window in the currently selected frame.

If this variable appears \"not to work\", because you add a
regexp to it but the matching buffers still appear in the
selected window, look at the values of `same-window-buffer-names'
and `same-window-regexps'.  Those variables take precedence over
this one."
  :type '(repeat (choice :tag "Buffer"
			 :value ""
			 (regexp :format "%v")
			 (cons :tag "With attributes"
			       :format "%v"
			       :value ("" . nil)
			       (regexp :format "%v")
			       (repeat :tag "Attributes"
				       (cons :format "%v"
					     (symbol :tag "Parameter")
					     (sexp :tag "Value"))))))
  :group 'frames)

(defcustom special-display-function 'special-display-popup-frame
  "Function to call to make a new frame for a special buffer.
It is called with two arguments, the buffer and optional buffer
specific data, and should return a window displaying that buffer.
The default value normally makes a separate frame for the buffer,
using `special-display-frame-alist' to specify the frame
parameters.

But if the buffer specific data includes (same-buffer . t) then
the buffer is displayed in the current selected window.
Otherwise if it includes (same-frame . t) then the buffer is
displayed in a new window in the currently selected frame.

A buffer is special if it is listed in
`special-display-buffer-names' or matches a regexp in
`special-display-regexps'."
  :type 'function
  :group 'frames)

(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 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 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 car must be a string, which specifies
the buffer name.  This is for compatibility with
`special-display-buffer-names'; the cdr of the cons cell is
ignored.

See also `same-window-buffer-names'."
  :type '(repeat (regexp :format "%v"))
  :group 'windows)

(defcustom pop-up-frames nil
  "Non-nil means `display-buffer' should make a separate frame."
  :type 'boolean
  :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-frame-function nil
  "Function to call to handle automatic new frame creation.
It is called with no arguments and should return a newly created frame.

A typical value might be

`(lambda () (new-frame pop-up-frame-alist))'

where `pop-up-frame-alist' would hold the default frame
parameters."
  :type '(choice
	  (const nil)
	  (function :tag "function"))
  :group 'windows)

(defcustom pop-up-windows t
  "Non-nil means `display-buffer' should make a new window."
  :type 'boolean
  :group 'windows)

(defcustom split-height-threshold 80
746 747 748 749 750 751 752 753
  "Minimum height of window to be split vertically.
If the value is a number, `display-buffer' can split a window
only if it has at least as many lines.  If the value is nil,
`display-buffer' cannot split a window vertically.

If the window is the only window on its frame, `display-buffer'
can split it regardless of this value."
  :type '(choice (const nil) (number :tag "lines"))
754 755 756 757 758
  :type 'number
  :version "23.1"
  :group 'windows)

(defcustom split-width-threshold 160
759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775
  "Minimum width of window to be split horizontally.
If the value is a number, `display-buffer' can split a window
only if it has at least as many columns.  If the value is nil,
`display-buffer' cannot split a window horizontally."
  :type '(choice (const nil) (number :tag "columns"))
  :version "23.1"
  :group 'windows)

(defcustom split-window-preferred-function nil
  "Function used by `display-buffer' to split windows.
If non-nil, a function called with a window as single argument
supposed to split that window and return the new window.  If the
function returns nil the window is not split.

If nil, `display-buffer' will split the window respecting the
values of `split-height-threshold' and `split-width-threshold'."
  :type '(choice (const nil) (function :tag "Function"))
776 777 778 779 780 781 782 783 784 785 786
  :version "23.1"
  :group 'windows)

(defun window--splittable-p (window &optional horizontal)
  "Return non-nil if window WINDOW can be split evenly.
Optional argument HORIZONTAL non-nil means check whether WINDOW
can be split horizontally.

WINDOW can be split vertically when the following conditions
hold:

787 788
- `window-size-fixed' is either nil or equals `width' for the
  buffer of WINDOW.
789

790 791
- `split-height-threshold' is a number and WINDOW is at least as
  high as `split-height-threshold'.
792 793 794 795 796 797 798 799 800 801 802

- When WINDOW is split evenly, the emanating windows are at least
  `window-min-height' lines tall and can accomodate at least one
  line plus - if WINDOW has one - a modeline.

WINDOW can be split horizontally when the following conditions
hold:

- `window-size-fixed' is either nil or equals `height' for the
  buffer of WINDOW.

803 804
- `split-width-threshold' is a number and WINDOW is at least as
  wide as `split-width-threshold'.
805 806 807 808

- 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)
809
    (with-current-buffer (window-buffer window)
810 811 812 813 814 815
      (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))
816 817 818 819
	       ;; 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)
820 821 822 823
	       (>= (window-width window)
		   (max split-width-threshold
			(* 2 (max window-min-width 2)))))
	;; A window can be split vertically when its height is not
824 825 826
	;; 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.
827
	(and (memq window-size-fixed '(nil width))
828
	     (numberp split-height-threshold)
829
	     (>= (window-height window)
830
		 (max split-height-threshold
831 832 833 834 835
		      (* 2 (max window-min-height
				(if mode-line-format 2 1))))))))))

(defun window--try-to-split-window (window)
  "Split window WINDOW if it is splittable.
836 837 838
See `window--splittable-p' for how to determine whether a window
is splittable.  If WINDOW can be split, return the value returned
by `split-window' or `split-window-preferred-function'."
839 840
  (when (and (window-live-p window)
	     (not (frame-parameter (window-frame window) 'unsplittable)))
841 842 843 844 845 846 847 848 849
    (if (functionp split-window-preferred-function)
	;; `split-window-preferred-function' is specified, so use it.
	(funcall split-window-preferred-function window)
      (or (and (window--splittable-p window)
	       ;; Split window vertically.
	       (split-window window))
	  (and (window--splittable-p window t)
	       ;; Split window horizontally.
	       (split-window window nil t))
850 851 852 853 854
	  (and (eq window (frame-root-window (window-frame window)))
	       (not (window-minibuffer-p window))
	       ;; If WINDOW is the only window on its frame and not the
	       ;; minibuffer window, attempt to split it vertically
	       ;; disregarding the value of `split-height-threshold'.
855 856 857
	       (let ((split-height-threshold 0))
		 (window--splittable-p window)
		 (split-window window)))))))
858 859 860

(defun window--frame-usable-p (frame)
  "Return frame FRAME if it can be used to display another buffer."
861 862 863 864 865 866 867 868 869
  (when (framep 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.
      (when (or (not (window-live-p window))
		(and (not (window-minibuffer-p window))
		     (not (window-dedicated-p window))))
	frame))))
870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944

(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)
  "Even heights of window WINDOW and selected window.
Do this only if these windows are vertically adjacent to each
other and `even-window-heights' is non-nil."
  (when (and even-window-heights
	     (not (eq window (selected-window)))
	     ;; Don't resize minibuffer windows.
	     (not (window-minibuffer-p (selected-window)))
	     (/= (window-height (selected-window)) (window-height window)) 
	     (eq (window-frame window) (window-frame (selected-window)))
	     (let ((sel-edges (window-edges (selected-window)))
		   (win-edges (window-edges window)))
	       (and (= (nth 0 sel-edges) (nth 0 win-edges))
		    (= (nth 2 sel-edges) (nth 2 win-edges))
		    (or (= (nth 1 sel-edges) (nth 3 win-edges))
			(= (nth 3 sel-edges) (nth 1 win-edges))))))
    (let ((window-min-height 1))
      ;; Don't throw an error if we can't even window heights for
      ;; whatever reason.
      (condition-case nil
	  (enlarge-window (/ (- (window-height window) (window-height)) 2))
	(error nil)))))

(defun window--display-buffer-1 (window)
  "Deiconify the frame containing the window WINDOW.
Do not deiconify the selected frame.  Return WINDOW."
  (let* ((frame (window-frame window))
	 (visible (frame-visible-p frame)))
    (unless (or (not visible)
		;; Assume the selected frame is already visible enough.
		(eq frame (selected-frame))
		;; Assume the frame from which we invoked the minibuffer
		;; is visible.
		(and (minibuffer-window-active-p (selected-window))
		     (eq frame (window-frame (minibuffer-selected-window)))))
      (when (eq visible 'icon)
	(make-frame-visible frame))
      (raise-frame frame))
    window))

(defun window--display-buffer-2 (buffer window)
  "Display buffer BUFFER in window WINDOW and make its frame visible.
Return WINDOW."
  (when (and (buffer-live-p buffer) (window-live-p window))
    (set-window-buffer window buffer)
    (window--display-buffer-1 window)))

(defun display-buffer (buffer-or-name &optional not-this-window frame)
  "Make buffer BUFFER-OR-NAME appear in some window but don't select it.
BUFFER-OR-NAME must be a buffer or the name of an existing
buffer.  Return the window chosen to display BUFFER-OR-NAME or
nil is no such window is found.

Optional argument NOT-THIS-WINDOW non-nil means display the
buffer in a window other than the selected one, even if it is
already displayed in the selected window.

Optional argument FRAME specifies which frames to investigate
when the specified buffer is already displayed.  If the buffer is
already displayed in some window on one of these frames simply
return that window.  Possible values of FRAME are:

`visible' - consider windows on all visible frames.

0 - consider windows on all visible or iconified frames.

945
t - consider windows on all frames.
946 947 948

A specific frame - consider windows on that frame only.

949
nil - consider windows on the selected frame \(actually the
950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001
last non-minibuffer frame\) only.  If, however, either
`display-buffer-reuse-frames' or `pop-up-frames' is non-nil,
consider all visible or iconified frames."
  (interactive "BDisplay buffer:\nP")
  (let* ((can-use-selected-window
	  ;; The selected window is usable unless either NOT-THIS-WINDOW
	  ;; is non-nil, it is dedicated to its buffer, or it is the
	  ;; `minibuffer-window'.
	  (not (or not-this-window
		   (window-dedicated-p (selected-window))
		   (window-minibuffer-p))))
	 (buffer (if (bufferp buffer-or-name)
		     buffer-or-name
		   (get-buffer buffer-or-name)))
	 (name-of-buffer (buffer-name buffer))
	 ;; `frame-to-use' is the frame where to show `buffer' - either
	 ;; the selected frame or the last nonminibuffer frame.
	 (frame-to-use
	  (or (window--frame-usable-p (selected-frame))
	      (window--frame-usable-p (last-nonminibuffer-frame))))
	 ;; `window-to-use' is the window we use for showing `buffer'.
	 window-to-use)
    (cond
     ((not (buffer-live-p buffer))
      (error "No such buffer %s" buffer))
     (display-buffer-function
      ;; Let `display-buffer-function' do the job.
      (funcall display-buffer-function buffer not-this-window))
     ((and (not not-this-window)
	   (eq (window-buffer (selected-window)) buffer))
      ;; The selected window already displays BUFFER and
      ;; `not-this-window' is nil, so use it.
      (window--display-buffer-1 (selected-window)))
     ((and can-use-selected-window (same-window-p name-of-buffer))
      ;; If the buffer's name tells us to use the selected window do so.
      (window--display-buffer-2 buffer (selected-window)))
     ((let ((frames (or frame
			(and (or pop-up-frames display-buffer-reuse-frames
				 (not (last-nonminibuffer-frame)))
			     0)
			(last-nonminibuffer-frame))))
	(and (setq window-to-use (get-buffer-window buffer frames))
	     (or can-use-selected-window
		 (not (eq (selected-window) window-to-use)))))
      ;; If the buffer is already displayed in some window use that.
      (window--display-buffer-1 window-to-use))
     ((and special-display-function
	   ;; `special-display-p' returns either t or a list of frame
	   ;; parameters to pass to `special-display-function'.
	   (let ((pars (special-display-p name-of-buffer)))
	     (when pars
	       (funcall special-display-function
1002
			buffer (if (listp pars) pars))))))
1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015
     ((or pop-up-frames (not frame-to-use))
      ;; We want or need a new frame.
      (window--display-buffer-2
       buffer (frame-selected-window (funcall pop-up-frame-function))))
     ((and pop-up-windows
	   ;; Make a new window.
	   (or (not (frame-parameter frame-to-use 'unsplittable))
	       ;; If the selected frame cannot be split look at
	       ;; `last-nonminibuffer-frame'.
	       (and (eq frame-to-use (selected-frame))
		    (setq frame-to-use (last-nonminibuffer-frame))
		    (window--frame-usable-p frame-to-use)
		    (not (frame-parameter frame-to-use 'unsplittable))))
1016
	   ;; Attempt to split largest or least recently used window.
1017 1018 1019 1020
	   (setq window-to-use
		 (or (window--try-to-split-window
		      (get-largest-window frame-to-use t))
		     (window--try-to-split-window
1021
		      (get-lru-window frame-to-use t))))
1022 1023 1024
	   (window--display-buffer-2 buffer window-to-use)))
     ((setq window-to-use
	    ;; Reuse an existing window.
1025 1026
	    (or (get-lru-window frame-to-use)
		(get-buffer-window buffer 'visible)
1027 1028 1029
		(get-largest-window 'visible nil)
		(get-buffer-window buffer 0)
		(get-largest-window 0 nil)
1030
		(frame-selected-window (funcall pop-up-frame-function))))
1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065
      (window--even-window-heights window-to-use)
      (window--display-buffer-2 buffer window-to-use)))))

(defun pop-to-buffer (buffer-or-name &optional other-window norecord)
  "Select buffer BUFFER-OR-NAME in some window, preferably a different one.
BUFFER-OR-NAME may be a buffer, a string \(a buffer name), or
nil.  If BUFFER-OR-NAME is a string not naming an existent
buffer, create a buffer with that name.  If BUFFER-OR-NAME is
nil, choose some other buffer.

If `pop-up-windows' is non-nil, windows can be split to display
the buffer.  If optional second arg OTHER-WINDOW is non-nil,
insist on finding another window even if the specified buffer is
already visible in the selected window, and ignore
`same-window-regexps' and `same-window-buffer-names'.

This function returns the buffer it switched to.  This uses the
function `display-buffer' as a subroutine; see the documentation
of `display-buffer' for additional customization information.

Optional third arg NORECORD non-nil means do not put this buffer
at the front of the list of recently selected ones."
  (let ((buffer
         ;; FIXME: This behavior is carried over from the previous C version
         ;; of pop-to-buffer, but really we should use just
         ;; `get-buffer' here.
         (if (null buffer-or-name) (other-buffer (current-buffer))
           (or (get-buffer buffer-or-name)
               (let ((buf (get-buffer-create buffer-or-name)))
                 (set-buffer-major-mode buf)
                 buf)))))
    (set-buffer buffer)
    (select-window (display-buffer buffer other-window) norecord)
    buffer))

1066
;; I think this should be the default; I think people will prefer it--rms.
Richard M. Stallman's avatar
Richard M. Stallman committed
1067
(defcustom split-window-keep-point t
1068
  "If non-nil, \\[split-window-vertically] keeps the original point \
1069
in both children.
1070 1071
This is often more convenient for editing.
If nil, adjust point in each of the two windows to minimize redisplay.
1072 1073 1074 1075
This is convenient on slow terminals, but point can move strangely.

This option applies only to `split-window-vertically' and
functions that call it.  `split-window' always keeps the original
1076
point in both children."
Richard M. Stallman's avatar
Richard M. Stallman committed
1077 1078
  :type 'boolean
  :group 'windows)
Jim Blandy's avatar
Jim Blandy committed
1079

Joseph Arceneaux's avatar
Joseph Arceneaux committed
1080 1081
(defun split-window-vertically (&optional arg)
  "Split current window into two windows, one above the other.
1082
The uppermost window gets ARG lines and the other gets the rest.
1083
Negative ARG means select the size of the lowermost window instead.
1084 1085 1086
With no argument, split equally or close to it.
Both windows display the same buffer now current.

1087
If the variable `split-window-keep-point' is non-nil, both new windows
Jim Blandy's avatar
Jim Blandy committed
1088
will get the same value of point as the current window.  This is often
1089
more convenient for editing.  The upper window is the selected window.
Jim Blandy's avatar
Jim Blandy committed
1090

1091
Otherwise, we choose window starts so as to minimize the amount of
Jim Blandy's avatar
Jim Blandy committed
1092 1093 1094
redisplay; this is convenient on slow terminals.  The new selected
window is the one that the current value of point appears in.  The
value of point can change if the text around point is hidden by the
1095 1096 1097 1098 1099
new mode line.

Regardless of the value of `split-window-keep-point', the upper
window is the original one and the return value is the new, lower
window."
Joseph Arceneaux's avatar
Joseph Arceneaux committed
1100 1101
  (interactive "P")
  (let ((old-w (selected-window))
1102
	(old-point (point))
1103
	(size (and arg (prefix-numeric-value arg)))
1104
        (window-full-p nil)
1105
	new-w bottom moved)
1106 1107
    (and size (< size 0) (setq size (+ (window-height) size)))
    (setq new-w (split-window nil size))
Jim Blandy's avatar
Jim Blandy committed
1108
    (or split-window-keep-point
1109
	(progn
Jim Blandy's avatar
Jim Blandy committed
1110 1111 1112
	  (save-excursion
	    (set-buffer (window-buffer))
	    (goto-char (window-start))
1113
            (setq moved (vertical-motion (window-height)))
Jim Blandy's avatar
Jim Blandy committed
1114 1115 1116
	    (set-window-start new-w (point))
	    (if (> (point) (window-point new-w))
		(set-window-point new-w (point)))
1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129
            (and (= moved (window-height))
                 (progn
                   (setq window-full-p t)
                   (vertical-motion -1)))
            (setq bottom (point)))
          (and window-full-p
               (<= bottom (point))
               (set-window-point old-w (1- bottom)))
	  (and window-full-p
               (<= (window-start new-w) old-point)
               (progn
                 (set-window-point new-w old-point)
                 (select-window new-w)))))
1130 1131
    (split-window-save-restore-data new-w old-w)))

1132 1133 1134
;; This is to avoid compiler warnings.
(defvar view-return-to-alist)

1135
(defun split-window-save-restore-data (new-w old-w)
1136
  (with-current-buffer (window-buffer)
1137 1138
    (if view-mode
	(let ((old-info (assq old-w view-return-to-alist)))
1139 1140 1141
	  (if old-info
	      (push (cons new-w (cons (car (cdr old-info)) t))
		    view-return-to-alist))))
1142
    new-w))
Joseph Arceneaux's avatar
Joseph Arceneaux committed
1143 1144 1145

(defun split-window-horizontally (&optional arg)
  "Split current window into two windows side by side.
1146
This window becomes the leftmost of the two, and gets ARG columns.
1147
Negative ARG means select the size of the rightmost window instead.
1148 1149
The argument includes the width of the window's scroll bar; if there
are no scroll bars, it includes the width of the divider column
1150 1151 1152 1153
to the window's right, if any.  No ARG means split equally.

The original, leftmost window remains selected.
The return value is the new, rightmost window."
Joseph Arceneaux's avatar
Joseph Arceneaux committed
1154
  (interactive "P")
1155 1156
  (let ((old-w (selected-window))
	(size (and arg (prefix-numeric-value arg))))
1157 1158
    (and size (< size 0)
	 (setq size (+ (window-width) size)))
1159
    (split-window-save-restore-data (split-window nil size t) old-w)))
1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173


(defun set-window-text-height (window height)
  "Sets the height in lines of the text display area of WINDOW to HEIGHT.
This doesn't include the mode-line (or header-line if any) or any
partial-height lines in the text display area.

If WINDOW is nil, the selected window is used.

Note that the current implementation of this function cannot always set
the height exactly, but attempts to be conservative, by allocating more
lines than are actually needed in the case where some error may be present."
  (let ((delta (- height (window-text-height window))))
    (unless (zerop delta)
1174 1175 1176 1177 1178
      ;; Setting window-min-height to a value like 1 can lead to very
      ;; bizarre displays because it also allows Emacs to make *other*
      ;; windows 1-line tall, which means that there's no more space for
      ;; the modeline.
      (let ((window-min-height (min 2 height))) ;One text line plus a modeline.
1179 1180 1181 1182 1183
	(if (and window (not (eq window (selected-window))))
	    (save-selected-window
	      (select-window window)
	      (enlarge-window delta))
	  (enlarge-window delta))))))
1184

1185

Joseph Arceneaux's avatar
Joseph Arceneaux committed
1186 1187 1188 1189 1190 1191 1192 1193 1194 1195
(defun enlarge-window-horizontally (arg)
  "Make current window ARG columns wider."
  (interactive "p")
  (enlarge-window arg t))

(defun shrink-window-horizontally (arg)
  "Make current window ARG columns narrower."
  (interactive "p")
  (shrink-window arg t))

1196 1197
(defun window-buffer-height (window)
  "Return the height (in screen lines) of the buffer that WINDOW is displaying."
1198 1199 1200 1201 1202 1203 1204
  (with-current-buffer (window-buffer window)
    (max 1
	 (count-screen-lines (point-min) (point-max)
			     ;; If buffer ends with a newline, ignore it when
			     ;; counting height unless point is after it.
			     (eobp)
			     window))))
1205

1206 1207 1208 1209 1210 1211 1212 1213
(defun count-screen-lines (&optional beg end count-final-newline window)
  "Return the number of screen lines in the region.
The number of screen lines may be different from the number of actual lines,
due to line breaking, display table, etc.

Optional arguments BEG and END default to `point-min' and `point-max'
respectively.

1214
If region ends with a newline, ignore it unless optional third argument
1215 1216 1217
COUNT-FINAL-NEWLINE is non-nil.

The optional fourth argument WINDOW specifies the window used for obtaining
1218
parameters such as width, horizontal scrolling, and so on.  The default is
1219 1220 1221
to use the selected window's parameters.

Like `vertical-motion', `count-screen-lines' always uses the current buffer,
1222
regardless of which buffer is displayed in WINDOW.  This makes possible to use
1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241
`count-screen-lines' in any buffer, whether or not it is currently displayed
in some window."
  (unless beg
    (setq beg (point-min)))
  (unless end
    (setq end (point-max)))
  (if (= beg end)
      0
    (save-excursion
      (save-restriction
        (widen)
        (narrow-to-region (min beg end)
                          (if (and (not count-final-newline)
                                   (= ?\n (char-before (max beg end))))
                              (1- (max beg end))
                            (max beg end)))
        (goto-char (point-min))
        (1+ (vertical-motion (buffer-size) window))))))

1242
(defun fit-window-to-buffer (&optional window max-height min-height)
1243
  "Make WINDOW the right height to display its contents exactly.
1244
If WINDOW is omitted or nil, it defaults to the selected window.
1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255
If the optional argument MAX-HEIGHT is supplied, it is the maximum height
  the window is allowed to be, defaulting to the frame height.
If the optional argument MIN-HEIGHT is supplied, it is the minimum
  height the window is allowed to be, defaulting to `window-min-height'.

The heights in MAX-HEIGHT and MIN-HEIGHT include the mode-line and/or
header-line."
  (interactive)

  (when (null window)
    (setq window (selected-window)))
1256 1257
  (when (null max-height)
    (setq max-height (frame-height (window-frame window))))
1258

1259 1260 1261 1262
  (let* ((buf
	  ;; Buffer that is displayed in WINDOW
	  (window-buffer window))
	 (window-height
1263 1264
	  ;; The current height of WINDOW
	  (window-height window))
1265
	 (desired-height