* viper-ex.el: Patch by Samuel Padgett. Copyright papers received.
[emacs.git] / lisp / window.el
blobcb4de12a9cf3930dac43aff15eb5bac6820d4d3b
1 ;;; window.el --- GNU Emacs window commands aside from those written in C
3 ;; Copyright (C) 1985, 1989, 1992, 1993, 1994, 2000, 2001, 2002
4 ;; Free Software Foundation, Inc.
6 ;; Maintainer: FSF
7 ;; Keywords: internal
9 ;; This file is part of GNU Emacs.
11 ;; GNU Emacs is free software; you can redistribute it and/or modify
12 ;; it under the terms of the GNU General Public License as published by
13 ;; the Free Software Foundation; either version 2, or (at your option)
14 ;; any later version.
16 ;; GNU Emacs is distributed in the hope that it will be useful,
17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 ;; GNU General Public License for more details.
21 ;; You should have received a copy of the GNU General Public License
22 ;; along with GNU Emacs; see the file COPYING. If not, write to the
23 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
24 ;; Boston, MA 02111-1307, USA.
26 ;;; Commentary:
28 ;; Window tree functions.
30 ;;; Code:
32 (defmacro save-selected-window (&rest body)
33 "Execute BODY, then select the window that was selected before BODY.
34 However, if that window has become dead, don't get an error,
35 just refrain from switching to it."
36 `(let ((save-selected-window-window (selected-window)))
37 (unwind-protect
38 (progn ,@body)
39 (if (window-live-p save-selected-window-window)
40 (select-window save-selected-window-window)))))
42 (defun window-body-height (&optional window)
43 "Return number of lines in window WINDOW for actual buffer text.
44 This does not include the mode line (if any) or the header line (if any)."
45 (or window (setq window (selected-window)))
46 (if (window-minibuffer-p window)
47 (window-height window)
48 (with-current-buffer (window-buffer window)
49 (max 1 (- (window-height window)
50 (if mode-line-format 1 0)
51 (if header-line-format 1 0))))))
53 (defun one-window-p (&optional nomini all-frames)
54 "Return non-nil if the selected window is the only window (in its frame).
55 Optional arg NOMINI non-nil means don't count the minibuffer
56 even if it is active.
58 The optional arg ALL-FRAMES t means count windows on all frames.
59 If it is `visible', count windows on all visible frames.
60 ALL-FRAMES nil or omitted means count only the selected frame,
61 plus the minibuffer it uses (which may be on another frame).
62 If ALL-FRAMES is neither nil nor t, count only the selected frame."
63 (let ((base-window (selected-window)))
64 (if (and nomini (eq base-window (minibuffer-window)))
65 (setq base-window (next-window base-window)))
66 (eq base-window
67 (next-window base-window (if nomini 'arg) all-frames))))
69 (defun walk-windows (proc &optional minibuf all-frames)
70 "Cycle through all visible windows, calling PROC for each one.
71 PROC is called with a window as argument.
73 Optional second arg MINIBUF t means count the minibuffer window even
74 if not active. MINIBUF nil or omitted means count the minibuffer iff
75 it is active. MINIBUF neither t nor nil means not to count the
76 minibuffer even if it is active.
78 Several frames may share a single minibuffer; if the minibuffer
79 counts, all windows on all frames that share that minibuffer count
80 too. Therefore, if you are using a separate minibuffer frame
81 and the minibuffer is active and MINIBUF says it counts,
82 `walk-windows' includes the windows in the frame from which you
83 entered the minibuffer, as well as the minibuffer window.
85 ALL-FRAMES is the optional third argument.
86 ALL-FRAMES nil or omitted means cycle within the frames as specified above.
87 ALL-FRAMES = `visible' means include windows on all visible frames.
88 ALL-FRAMES = 0 means include windows on all visible and iconified frames.
89 ALL-FRAMES = t means include windows on all frames including invisible frames.
90 If ALL-FRAMES is a frame, it means include windows on that frame.
91 Anything else means restrict to the selected frame."
92 ;; If we start from the minibuffer window, don't fail to come back to it.
93 (if (window-minibuffer-p (selected-window))
94 (setq minibuf t))
95 (save-selected-window
96 (if (framep all-frames)
97 (select-window (frame-first-window all-frames)))
98 (let* (walk-windows-already-seen
99 (walk-windows-current (selected-window)))
100 (while (progn
101 (setq walk-windows-current
102 (next-window walk-windows-current minibuf all-frames))
103 (not (memq walk-windows-current walk-windows-already-seen)))
104 (setq walk-windows-already-seen
105 (cons walk-windows-current walk-windows-already-seen))
106 (funcall proc walk-windows-current)))))
108 (defun get-window-with-predicate (predicate &optional minibuf
109 all-frames default)
110 "Return a window satisfying PREDICATE.
112 This function cycles through all visible windows using `walk-windows',
113 calling PREDICATE on each one. PREDICATE is called with a window as
114 argument. The first window for which PREDICATE returns a non-nil
115 value is returned. If no window satisfies PREDICATE, DEFAULT is
116 returned.
118 Optional second arg MINIBUF t means count the minibuffer window even
119 if not active. MINIBUF nil or omitted means count the minibuffer iff
120 it is active. MINIBUF neither t nor nil means not to count the
121 minibuffer even if it is active.
123 Several frames may share a single minibuffer; if the minibuffer
124 counts, all windows on all frames that share that minibuffer count
125 too. Therefore, if you are using a separate minibuffer frame
126 and the minibuffer is active and MINIBUF says it counts,
127 `walk-windows' includes the windows in the frame from which you
128 entered the minibuffer, as well as the minibuffer window.
130 ALL-FRAMES is the optional third argument.
131 ALL-FRAMES nil or omitted means cycle within the frames as specified above.
132 ALL-FRAMES = `visible' means include windows on all visible frames.
133 ALL-FRAMES = 0 means include windows on all visible and iconified frames.
134 ALL-FRAMES = t means include windows on all frames including invisible frames.
135 If ALL-FRAMES is a frame, it means include windows on that frame.
136 Anything else means restrict to the selected frame."
137 (catch 'found
138 (walk-windows #'(lambda (window)
139 (when (funcall predicate window)
140 (throw 'found window)))
141 minibuf all-frames)
142 default))
144 (defalias 'some-window 'get-window-with-predicate)
146 (defun minibuffer-window-active-p (window)
147 "Return t if WINDOW (a minibuffer window) is now active."
148 (eq window (active-minibuffer-window)))
150 (defun count-windows (&optional minibuf)
151 "Return the number of visible windows.
152 This counts the windows in the selected frame and (if the minibuffer is
153 to be counted) its minibuffer frame (if that's not the same frame).
154 The optional arg MINIBUF non-nil means count the minibuffer
155 even if it is inactive."
156 (let ((count 0))
157 (walk-windows (function (lambda (w)
158 (setq count (+ count 1))))
159 minibuf)
160 count))
162 (defun window-safely-shrinkable-p (&optional window)
163 "Non-nil if the WINDOW can be shrunk without shrinking other windows.
164 If WINDOW is nil or omitted, it defaults to the currently selected window."
165 (save-selected-window
166 (when window (select-window window))
167 (or (and (not (eq window (frame-first-window)))
168 (= (car (window-edges))
169 (car (window-edges (previous-window)))))
170 (= (car (window-edges))
171 (car (window-edges (next-window)))))))
173 (defun balance-windows ()
174 "Make all visible windows the same height (approximately)."
175 (interactive)
176 (let ((count -1) levels newsizes level-size
177 ;; Don't count the lines that are above the uppermost windows.
178 ;; (These are the menu bar lines, if any.)
179 (mbl (nth 1 (window-edges (frame-first-window (selected-frame)))))
180 (last-window (previous-window (frame-first-window (selected-frame))))
181 ;; Don't count the lines that are past the lowest main window.
182 total)
183 ;; Bottom edge of last window determines what size we have to work with.
184 (setq total
185 (+ (window-height last-window)
186 (nth 1 (window-edges last-window))))
188 ;; Find all the different vpos's at which windows start,
189 ;; then count them. But ignore levels that differ by only 1.
190 (let (tops (prev-top -2))
191 (walk-windows (function (lambda (w)
192 (setq tops (cons (nth 1 (window-edges w))
193 tops))))
194 'nomini)
195 (setq tops (sort tops '<))
196 (while tops
197 (if (> (car tops) (1+ prev-top))
198 (setq prev-top (car tops)
199 count (1+ count)))
200 (setq levels (cons (cons (car tops) count) levels))
201 (setq tops (cdr tops)))
202 (setq count (1+ count)))
203 ;; Subdivide the frame into desired number of vertical levels.
204 (setq level-size (/ (- total mbl) count))
205 (save-selected-window
206 ;; Set up NEWSIZES to map windows to their desired sizes.
207 ;; If a window ends at the bottom level, don't include
208 ;; it in NEWSIZES. Those windows get the right sizes
209 ;; by adjusting the ones above them.
210 (walk-windows (function
211 (lambda (w)
212 (let ((newtop (cdr (assq (nth 1 (window-edges w))
213 levels)))
214 (newbot (cdr (assq (+ (window-height w)
215 (nth 1 (window-edges w)))
216 levels))))
217 (if newbot
218 (setq newsizes
219 (cons (cons w (* level-size (- newbot newtop)))
220 newsizes))))))
221 'nomini)
222 ;; Make walk-windows start with the topmost window.
223 (select-window (previous-window (frame-first-window (selected-frame))))
224 (let (done (count 0))
225 ;; Give each window its precomputed size, or at least try.
226 ;; Keep trying until they all get the intended sizes,
227 ;; but not more than 3 times (to prevent infinite loop).
228 (while (and (not done) (< count 3))
229 (setq done t)
230 (setq count (1+ count))
231 (walk-windows (function (lambda (w)
232 (select-window w)
233 (let ((newsize (cdr (assq w newsizes))))
234 (when newsize
235 (enlarge-window (- newsize
236 (window-height))
237 nil t)
238 (unless (= (window-height) newsize)
239 (setq done nil))))))
240 'nomini))))))
242 ;;; I think this should be the default; I think people will prefer it--rms.
243 (defcustom split-window-keep-point t
244 "*If non-nil, split windows keeps the original point in both children.
245 This is often more convenient for editing.
246 If nil, adjust point in each of the two windows to minimize redisplay.
247 This is convenient on slow terminals, but point can move strangely."
248 :type 'boolean
249 :group 'windows)
251 (defun split-window-vertically (&optional arg)
252 "Split current window into two windows, one above the other.
253 The uppermost window gets ARG lines and the other gets the rest.
254 Negative arg means select the size of the lowermost window instead.
255 With no argument, split equally or close to it.
256 Both windows display the same buffer now current.
258 If the variable `split-window-keep-point' is non-nil, both new windows
259 will get the same value of point as the current window. This is often
260 more convenient for editing.
262 Otherwise, we chose window starts so as to minimize the amount of
263 redisplay; this is convenient on slow terminals. The new selected
264 window is the one that the current value of point appears in. The
265 value of point can change if the text around point is hidden by the
266 new mode line."
267 (interactive "P")
268 (let ((old-w (selected-window))
269 (old-point (point))
270 (size (and arg (prefix-numeric-value arg)))
271 (window-full-p nil)
272 new-w bottom switch moved)
273 (and size (< size 0) (setq size (+ (window-height) size)))
274 (setq new-w (split-window nil size))
275 (or split-window-keep-point
276 (progn
277 (save-excursion
278 (set-buffer (window-buffer))
279 (goto-char (window-start))
280 (setq moved (vertical-motion (window-height)))
281 (set-window-start new-w (point))
282 (if (> (point) (window-point new-w))
283 (set-window-point new-w (point)))
284 (and (= moved (window-height))
285 (progn
286 (setq window-full-p t)
287 (vertical-motion -1)))
288 (setq bottom (point)))
289 (and window-full-p
290 (<= bottom (point))
291 (set-window-point old-w (1- bottom)))
292 (and window-full-p
293 (<= (window-start new-w) old-point)
294 (progn
295 (set-window-point new-w old-point)
296 (select-window new-w)))))
297 (split-window-save-restore-data new-w old-w)))
299 ;; This is to avoid compiler warnings.
300 (defvar view-return-to-alist)
302 (defun split-window-save-restore-data (new-w old-w)
303 (save-excursion
304 (set-buffer (window-buffer))
305 (if view-mode
306 (let ((old-info (assq old-w view-return-to-alist)))
307 (setq view-return-to-alist
308 (cons (cons new-w (cons (and old-info (car (cdr old-info))) t))
309 view-return-to-alist))))
310 new-w))
312 (defun split-window-horizontally (&optional arg)
313 "Split current window into two windows side by side.
314 This window becomes the leftmost of the two, and gets ARG columns.
315 Negative arg means select the size of the rightmost window instead.
316 The argument includes the width of the window's scroll bar; if there
317 are no scroll bars, it includes the width of the divider column
318 to the window's right, if any. No arg means split equally."
319 (interactive "P")
320 (let ((old-w (selected-window))
321 (size (and arg (prefix-numeric-value arg))))
322 (and size (< size 0)
323 (setq size (+ (window-width) size)))
324 (split-window-save-restore-data (split-window nil size t) old-w)))
327 (defun set-window-text-height (window height)
328 "Sets the height in lines of the text display area of WINDOW to HEIGHT.
329 This doesn't include the mode-line (or header-line if any) or any
330 partial-height lines in the text display area.
332 If WINDOW is nil, the selected window is used.
334 Note that the current implementation of this function cannot always set
335 the height exactly, but attempts to be conservative, by allocating more
336 lines than are actually needed in the case where some error may be present."
337 (let ((delta (- height (window-text-height window))))
338 (unless (zerop delta)
339 (let ((window-min-height 1))
340 (if (and window (not (eq window (selected-window))))
341 (save-selected-window
342 (select-window window)
343 (enlarge-window delta))
344 (enlarge-window delta))))))
347 (defun enlarge-window-horizontally (arg)
348 "Make current window ARG columns wider."
349 (interactive "p")
350 (enlarge-window arg t))
352 (defun shrink-window-horizontally (arg)
353 "Make current window ARG columns narrower."
354 (interactive "p")
355 (shrink-window arg t))
357 (defun window-buffer-height (window)
358 "Return the height (in screen lines) of the buffer that WINDOW is displaying."
359 (save-excursion
360 (set-buffer (window-buffer window))
361 (goto-char (point-min))
362 (let ((ignore-final-newline
363 ;; If buffer ends with a newline, ignore it when counting height
364 ;; unless point is after it.
365 (and (not (eobp)) (eq ?\n (char-after (1- (point-max)))))))
366 (+ 1 (nth 2 (compute-motion (point-min)
367 '(0 . 0)
368 (- (point-max) (if ignore-final-newline 1 0))
369 (cons 0 100000000)
370 (window-width window)
372 window))))))
374 (defun count-screen-lines (&optional beg end count-final-newline window)
375 "Return the number of screen lines in the region.
376 The number of screen lines may be different from the number of actual lines,
377 due to line breaking, display table, etc.
379 Optional arguments BEG and END default to `point-min' and `point-max'
380 respectively.
382 If region ends with a newline, ignore it unless optional third argument
383 COUNT-FINAL-NEWLINE is non-nil.
385 The optional fourth argument WINDOW specifies the window used for obtaining
386 parameters such as width, horizontal scrolling, and so on. The default is
387 to use the selected window's parameters.
389 Like `vertical-motion', `count-screen-lines' always uses the current buffer,
390 regardless of which buffer is displayed in WINDOW. This makes possible to use
391 `count-screen-lines' in any buffer, whether or not it is currently displayed
392 in some window."
393 (unless beg
394 (setq beg (point-min)))
395 (unless end
396 (setq end (point-max)))
397 (if (= beg end)
399 (save-excursion
400 (save-restriction
401 (widen)
402 (narrow-to-region (min beg end)
403 (if (and (not count-final-newline)
404 (= ?\n (char-before (max beg end))))
405 (1- (max beg end))
406 (max beg end)))
407 (goto-char (point-min))
408 (1+ (vertical-motion (buffer-size) window))))))
410 (defun fit-window-to-buffer (&optional window max-height min-height)
411 "Make WINDOW the right size to display its contents exactly.
412 If WINDOW is omitted or nil, it defaults to the selected window.
413 If the optional argument MAX-HEIGHT is supplied, it is the maximum height
414 the window is allowed to be, defaulting to the frame height.
415 If the optional argument MIN-HEIGHT is supplied, it is the minimum
416 height the window is allowed to be, defaulting to `window-min-height'.
418 The heights in MAX-HEIGHT and MIN-HEIGHT include the mode-line and/or
419 header-line."
420 (interactive)
422 (when (null window)
423 (setq window (selected-window)))
424 (when (null max-height)
425 (setq max-height (frame-height (window-frame window))))
427 (let* ((buf
428 ;; Buffer that is displayed in WINDOW
429 (window-buffer window))
430 (window-height
431 ;; The current height of WINDOW
432 (window-height window))
433 (desired-height
434 ;; The height necessary to show the buffer displayed by WINDOW
435 ;; (`count-screen-lines' always works on the current buffer).
436 (with-current-buffer buf
437 (+ (count-screen-lines)
438 ;; If the buffer is empty, (count-screen-lines) is
439 ;; zero. But, even in that case, we need one text line
440 ;; for cursor.
441 (if (= (point-min) (point-max))
442 1 0)
443 ;; For non-minibuffers, count the mode-line, if any
444 (if (and (not (window-minibuffer-p window))
445 mode-line-format)
446 1 0)
447 ;; Count the header-line, if any
448 (if header-line-format 1 0))))
449 (delta
450 ;; Calculate how much the window height has to change to show
451 ;; desired-height lines, constrained by MIN-HEIGHT and MAX-HEIGHT.
452 (- (max (min desired-height max-height)
453 (or min-height window-min-height))
454 window-height))
455 ;; We do our own height checking, so avoid any restrictions due to
456 ;; window-min-height.
457 (window-min-height 1))
459 ;; Don't try to redisplay with the cursor at the end
460 ;; on its own line--that would force a scroll and spoil things.
461 (when (with-current-buffer buf
462 (and (eobp) (bolp) (not (bobp))))
463 (set-window-point window (1- (window-point window))))
465 (save-selected-window
466 (select-window window)
468 ;; Adjust WINDOW to the nominally correct size (which may actually
469 ;; be slightly off because of variable height text, etc).
470 (unless (zerop delta)
471 (enlarge-window delta))
473 ;; Check if the last line is surely fully visible. If not,
474 ;; enlarge the window.
475 (let ((end (with-current-buffer buf
476 (save-excursion
477 (goto-char (point-max))
478 (when (and (bolp) (not (bobp)))
479 ;; Don't include final newline
480 (backward-char 1))
481 (when truncate-lines
482 ;; If line-wrapping is turned off, test the
483 ;; beginning of the last line for visibility
484 ;; instead of the end, as the end of the line
485 ;; could be invisible by virtue of extending past
486 ;; the edge of the window.
487 (forward-line 0))
488 (point)))))
489 (set-window-vscroll window 0)
490 (while (and (< desired-height max-height)
491 (= desired-height (window-height window))
492 (not (pos-visible-in-window-p end window)))
493 (enlarge-window 1)
494 (setq desired-height (1+ desired-height)))))))
496 (defun shrink-window-if-larger-than-buffer (&optional window)
497 "Shrink the WINDOW to be as small as possible to display its contents.
498 If WINDOW is omitted or nil, it defaults to the selected window.
499 Do not shrink to less than `window-min-height' lines.
500 Do nothing if the buffer contains more lines than the present window height,
501 or if some of the window's contents are scrolled out of view,
502 or if shrinking this window would also shrink another window.
503 or if the window is the only window of its frame.
504 Return non-nil if the window was shrunk."
505 (interactive)
506 (when (null window)
507 (setq window (selected-window)))
508 (let* ((frame (window-frame window))
509 (mini (frame-parameter frame 'minibuffer))
510 (edges (window-edges window)))
511 (if (and (not (eq window (frame-root-window frame)))
512 (window-safely-shrinkable-p)
513 (pos-visible-in-window-p (point-min) window)
514 (not (eq mini 'only))
515 (or (not mini)
516 (let ((mini-window (minibuffer-window frame)))
517 (or (null mini-window)
518 (not (eq frame (window-frame mini-window)))
519 (< (nth 3 edges)
520 (nth 1 (window-edges mini-window)))
521 (> (nth 1 edges)
522 (frame-parameter frame 'menu-bar-lines))))))
523 (fit-window-to-buffer window (window-height window)))))
525 (defun kill-buffer-and-window ()
526 "Kill the current buffer and delete the selected window."
527 (interactive)
528 (if (yes-or-no-p (format "Kill buffer `%s'? " (buffer-name)))
529 (let ((buffer (current-buffer)))
530 (delete-window (selected-window))
531 (kill-buffer buffer))
532 (error "Aborted")))
534 (defun quit-window (&optional kill window)
535 "Quit the current buffer. Bury it, and maybe delete the selected frame.
536 \(The frame is deleted if it is contains a dedicated window for the buffer.)
537 With a prefix argument, kill the buffer instead.
539 Noninteractively, if KILL is non-nil, then kill the current buffer,
540 otherwise bury it.
542 If WINDOW is non-nil, it specifies a window; we delete that window,
543 and the buffer that is killed or buried is the one in that window."
544 (interactive "P")
545 (let ((buffer (window-buffer window))
546 (frame (window-frame (or window (selected-window))))
547 (window-solitary
548 (save-selected-window
549 (if window
550 (select-window window))
551 (one-window-p t)))
552 window-handled)
554 (save-selected-window
555 (if window
556 (select-window window))
557 (or (window-minibuffer-p)
558 (window-dedicated-p (selected-window))
559 (switch-to-buffer (other-buffer))))
561 ;; Get rid of the frame, if it has just one dedicated window
562 ;; and other visible frames exist.
563 (and (or (window-minibuffer-p) (window-dedicated-p window))
564 (delq frame (visible-frame-list))
565 window-solitary
566 (if (and (eq default-minibuffer-frame frame)
567 (= 1 (length (minibuffer-frame-list))))
568 (setq window nil)
569 (delete-frame frame)
570 (setq window-handled t)))
572 ;; Deal with the buffer.
573 (if kill
574 (kill-buffer buffer)
575 (bury-buffer buffer))
577 ;; Maybe get rid of the window.
578 (and window (not window-handled) (not window-solitary)
579 (delete-window window))))
581 (defun handle-select-window (event)
582 "Handle select-window events."
583 (interactive "e")
584 (let ((window (posn-window (event-start event))))
585 (if (or (not (window-minibuffer-p window))
586 (minibuffer-window-active-p window))
587 (select-window window))))
589 (define-key ctl-x-map "2" 'split-window-vertically)
590 (define-key ctl-x-map "3" 'split-window-horizontally)
591 (define-key ctl-x-map "}" 'enlarge-window-horizontally)
592 (define-key ctl-x-map "{" 'shrink-window-horizontally)
593 (define-key ctl-x-map "-" 'shrink-window-if-larger-than-buffer)
594 (define-key ctl-x-map "+" 'balance-windows)
595 (define-key ctl-x-4-map "0" 'kill-buffer-and-window)
597 ;;; window.el ends here