1 ;;; window.el --- GNU Emacs window commands aside from those written in C
3 ;; Copyright (C) 1985, 1989, 1992, 1993, 1994, 2000, 2001
4 ;; Free Software Foundation, Inc.
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)
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.
28 ;; Window tree functions.
32 (defun one-window-p (&optional nomini all-frames)
33 "Return non-nil if the selected window is the only window (in its frame).
34 Optional arg NOMINI non-nil means don't count the minibuffer
37 The optional arg ALL-FRAMES t means count windows on all frames.
38 If it is `visible', count windows on all visible frames.
39 ALL-FRAMES nil or omitted means count only the selected frame,
40 plus the minibuffer it uses (which may be on another frame).
41 If ALL-FRAMES is neither nil nor t, count only the selected frame."
42 (let ((base-window (selected-window)))
43 (if (and nomini (eq base-window (minibuffer-window)))
44 (setq base-window (next-window base-window)))
46 (next-window base-window (if nomini 'arg) all-frames))))
48 (defun walk-windows (proc &optional minibuf all-frames)
49 "Cycle through all visible windows, calling PROC for each one.
50 PROC is called with a window as argument.
52 Optional second arg MINIBUF t means count the minibuffer window even
53 if not active. MINIBUF nil or omitted means count the minibuffer iff
54 it is active. MINIBUF neither t nor nil means not to count the
55 minibuffer even if it is active.
57 Several frames may share a single minibuffer; if the minibuffer
58 counts, all windows on all frames that share that minibuffer count
59 too. Therefore, if you are using a separate minibuffer frame
60 and the minibuffer is active and MINIBUF says it counts,
61 `walk-windows' includes the windows in the frame from which you
62 entered the minibuffer, as well as the minibuffer window.
64 ALL-FRAMES is the optional third argument.
65 ALL-FRAMES nil or omitted means cycle within the frames as specified above.
66 ALL-FRAMES = `visible' means include windows on all visible frames.
67 ALL-FRAMES = 0 means include windows on all visible and iconified frames.
68 ALL-FRAMES = t means include windows on all frames including invisible frames.
69 If ALL-FRAMES is a frame, it means include windows on that frame.
70 Anything else means restrict to the selected frame."
71 ;; If we start from the minibuffer window, don't fail to come back to it.
72 (if (window-minibuffer-p (selected-window))
75 (if (framep all-frames)
76 (select-window (frame-first-window all-frames)))
77 (let* (walk-windows-already-seen
78 (walk-windows-current (selected-window)))
80 (setq walk-windows-current
81 (next-window walk-windows-current minibuf all-frames))
82 (not (memq walk-windows-current walk-windows-already-seen)))
83 (setq walk-windows-already-seen
84 (cons walk-windows-current walk-windows-already-seen))
85 (funcall proc walk-windows-current)))))
87 (defun get-window-with-predicate (predicate &optional minibuf
89 "Return a window satisfying PREDICATE.
91 This function cycles through all visible windows using `walk-windows',
92 calling PREDICATE on each one. PREDICATE is called with a window as
93 argument. The first window for which PREDICATE returns a non-nil
94 value is returned. If no window satisfies PREDICATE, DEFAULT is
97 Optional second arg MINIBUF t means count the minibuffer window even
98 if not active. MINIBUF nil or omitted means count the minibuffer iff
99 it is active. MINIBUF neither t nor nil means not to count the
100 minibuffer even if it is active.
102 Several frames may share a single minibuffer; if the minibuffer
103 counts, all windows on all frames that share that minibuffer count
104 too. Therefore, if you are using a separate minibuffer frame
105 and the minibuffer is active and MINIBUF says it counts,
106 `walk-windows' includes the windows in the frame from which you
107 entered the minibuffer, as well as the minibuffer window.
109 ALL-FRAMES is the optional third argument.
110 ALL-FRAMES nil or omitted means cycle within the frames as specified above.
111 ALL-FRAMES = `visible' means include windows on all visible frames.
112 ALL-FRAMES = 0 means include windows on all visible and iconified frames.
113 ALL-FRAMES = t means include windows on all frames including invisible frames.
114 If ALL-FRAMES is a frame, it means include windows on that frame.
115 Anything else means restrict to the selected frame."
117 (walk-windows #'(lambda (window)
118 (when (funcall predicate window)
119 (throw 'found window)))
123 (defalias 'some-window 'get-window-with-predicate)
125 (defun minibuffer-window-active-p (window)
126 "Return t if WINDOW (a minibuffer window) is now active."
127 (eq window (active-minibuffer-window)))
129 (defmacro save-selected-window (&rest body)
130 "Execute BODY, then select the window that was selected before BODY."
131 `(let ((save-selected-window-window (selected-window)))
134 (select-window save-selected-window-window))))
136 (defun count-windows (&optional minibuf)
137 "Return the number of visible windows.
138 This counts the windows in the selected frame and (if the minibuffer is
139 to be counted) its minibuffer frame (if that's not the same frame).
140 The optional arg MINIBUF non-nil means count the minibuffer
141 even if it is inactive."
143 (walk-windows (function (lambda (w)
144 (setq count (+ count 1))))
148 (defun window-safely-shrinkable-p (&optional window)
149 "Non-nil if the WINDOW can be shrunk without shrinking other windows.
150 If WINDOW is nil or omitted, it defaults to the currently selected window."
151 (save-selected-window
152 (when window (select-window window))
153 (or (and (not (eq window (frame-first-window)))
154 (= (car (window-edges))
155 (car (window-edges (previous-window)))))
156 (= (car (window-edges))
157 (car (window-edges (next-window)))))))
159 (defun balance-windows ()
160 "Make all visible windows the same height (approximately)."
162 (let ((count -1) levels newsizes size
163 ;; Don't count the lines that are above the uppermost windows.
164 ;; (These are the menu bar lines, if any.)
165 (mbl (nth 1 (window-edges (frame-first-window (selected-frame))))))
166 ;; Find all the different vpos's at which windows start,
167 ;; then count them. But ignore levels that differ by only 1.
168 (save-window-excursion
169 (let (tops (prev-top -2))
170 (walk-windows (function (lambda (w)
171 (setq tops (cons (nth 1 (window-edges w))
174 (setq tops (sort tops '<))
176 (if (> (car tops) (1+ prev-top))
177 (setq prev-top (car tops)
179 (setq levels (cons (cons (car tops) count) levels))
180 (setq tops (cdr tops)))
181 (setq count (1+ count))))
182 ;; Subdivide the frame into that many vertical levels.
183 (setq size (/ (- (frame-height) mbl) count))
184 (walk-windows (function
187 (let ((newtop (cdr (assq (nth 1 (window-edges))
189 (newbot (or (cdr (assq (+ (window-height)
190 (nth 1 (window-edges)))
194 (cons (cons w (* size (- newbot newtop)))
197 (walk-windows (function (lambda (w)
199 (let ((newsize (cdr (assq w newsizes))))
200 (enlarge-window (- newsize
204 ;;; I think this should be the default; I think people will prefer it--rms.
205 (defcustom split-window-keep-point t
206 "*If non-nil, split windows keeps the original point in both children.
207 This is often more convenient for editing.
208 If nil, adjust point in each of the two windows to minimize redisplay.
209 This is convenient on slow terminals, but point can move strangely."
213 (defun split-window-vertically (&optional arg)
214 "Split current window into two windows, one above the other.
215 The uppermost window gets ARG lines and the other gets the rest.
216 Negative arg means select the size of the lowermost window instead.
217 With no argument, split equally or close to it.
218 Both windows display the same buffer now current.
220 If the variable `split-window-keep-point' is non-nil, both new windows
221 will get the same value of point as the current window. This is often
222 more convenient for editing.
224 Otherwise, we chose window starts so as to minimize the amount of
225 redisplay; this is convenient on slow terminals. The new selected
226 window is the one that the current value of point appears in. The
227 value of point can change if the text around point is hidden by the
230 (let ((old-w (selected-window))
232 (size (and arg (prefix-numeric-value arg)))
234 new-w bottom switch moved)
235 (and size (< size 0) (setq size (+ (window-height) size)))
236 (setq new-w (split-window nil size))
237 (or split-window-keep-point
240 (set-buffer (window-buffer))
241 (goto-char (window-start))
242 (setq moved (vertical-motion (window-height)))
243 (set-window-start new-w (point))
244 (if (> (point) (window-point new-w))
245 (set-window-point new-w (point)))
246 (and (= moved (window-height))
248 (setq window-full-p t)
249 (vertical-motion -1)))
250 (setq bottom (point)))
253 (set-window-point old-w (1- bottom)))
255 (<= (window-start new-w) old-point)
257 (set-window-point new-w old-point)
258 (select-window new-w)))))
259 (split-window-save-restore-data new-w old-w)))
261 ;; This is to avoid compiler warnings.
262 (defvar view-return-to-alist)
264 (defun split-window-save-restore-data (new-w old-w)
266 (set-buffer (window-buffer))
268 (let ((old-info (assq old-w view-return-to-alist)))
269 (setq view-return-to-alist
270 (cons (cons new-w (cons (and old-info (car (cdr old-info))) t))
271 view-return-to-alist))))
274 (defun split-window-horizontally (&optional arg)
275 "Split current window into two windows side by side.
276 This window becomes the leftmost of the two, and gets ARG columns.
277 Negative arg means select the size of the rightmost window instead.
278 The argument includes the width of the window's scroll bar; if there
279 are no scroll bars, it includes the width of the divider column
280 to the window's right, if any. No arg means split equally."
282 (let ((old-w (selected-window))
283 (size (and arg (prefix-numeric-value arg))))
285 (setq size (+ (window-width) size)))
286 (split-window-save-restore-data (split-window nil size t) old-w)))
289 (defun set-window-text-height (window height)
290 "Sets the height in lines of the text display area of WINDOW to HEIGHT.
291 This doesn't include the mode-line (or header-line if any) or any
292 partial-height lines in the text display area.
294 If WINDOW is nil, the selected window is used.
296 Note that the current implementation of this function cannot always set
297 the height exactly, but attempts to be conservative, by allocating more
298 lines than are actually needed in the case where some error may be present."
299 (let ((delta (- height (window-text-height window))))
300 (unless (zerop delta)
301 (let ((window-min-height 1))
302 (if (and window (not (eq window (selected-window))))
303 (save-selected-window
304 (select-window window)
305 (enlarge-window delta))
306 (enlarge-window delta))))))
309 (defun enlarge-window-horizontally (arg)
310 "Make current window ARG columns wider."
312 (enlarge-window arg t))
314 (defun shrink-window-horizontally (arg)
315 "Make current window ARG columns narrower."
317 (shrink-window arg t))
319 (defun window-buffer-height (window)
320 "Return the height (in screen lines) of the buffer that WINDOW is displaying."
322 (set-buffer (window-buffer window))
323 (goto-char (point-min))
324 (let ((ignore-final-newline
325 ;; If buffer ends with a newline, ignore it when counting height
326 ;; unless point is after it.
327 (and (not (eobp)) (eq ?\n (char-after (1- (point-max)))))))
328 (+ 1 (nth 2 (compute-motion (point-min)
330 (- (point-max) (if ignore-final-newline 1 0))
332 (window-width window)
336 (defun count-screen-lines (&optional beg end count-final-newline window)
337 "Return the number of screen lines in the region.
338 The number of screen lines may be different from the number of actual lines,
339 due to line breaking, display table, etc.
341 Optional arguments BEG and END default to `point-min' and `point-max'
344 If region ends with a newline, ignore it unless optional third argument
345 COUNT-FINAL-NEWLINE is non-nil.
347 The optional fourth argument WINDOW specifies the window used for obtaining
348 parameters such as width, horizontal scrolling, and so on. The default is
349 to use the selected window's parameters.
351 Like `vertical-motion', `count-screen-lines' always uses the current buffer,
352 regardless of which buffer is displayed in WINDOW. This makes possible to use
353 `count-screen-lines' in any buffer, whether or not it is currently displayed
356 (setq beg (point-min)))
358 (setq end (point-max)))
364 (narrow-to-region (min beg end)
365 (if (and (not count-final-newline)
366 (= ?\n (char-before (max beg end))))
369 (goto-char (point-min))
370 (1+ (vertical-motion (buffer-size) window))))))
372 (defun fit-window-to-buffer (&optional window max-height min-height)
373 "Make WINDOW the right size to display its contents exactly.
374 If WINDOW is omitted or nil, it defaults to the selected window.
375 If the optional argument MAX-HEIGHT is supplied, it is the maximum height
376 the window is allowed to be, defaulting to the frame height.
377 If the optional argument MIN-HEIGHT is supplied, it is the minimum
378 height the window is allowed to be, defaulting to `window-min-height'.
380 The heights in MAX-HEIGHT and MIN-HEIGHT include the mode-line and/or
385 (setq window (selected-window)))
386 (when (null max-height)
387 (setq max-height (frame-height (window-frame window))))
390 ;; Buffer that is displayed in WINDOW
391 (window-buffer window))
393 ;; The current height of WINDOW
394 (window-height window))
396 ;; The height necessary to show the buffer displayed by WINDOW
397 ;; (`count-screen-lines' always works on the current buffer).
398 (with-current-buffer buf
399 (+ (count-screen-lines)
400 ;; If the buffer is empty, (count-screen-lines) is
401 ;; zero. But, even in that case, we need one text line
403 (if (= (point-min) (point-max))
405 ;; For non-minibuffers, count the mode-line, if any
406 (if (and (not (window-minibuffer-p window))
409 ;; Count the header-line, if any
410 (if header-line-format 1 0))))
412 ;; Calculate how much the window height has to change to show
413 ;; desired-height lines, constrained by MIN-HEIGHT and MAX-HEIGHT.
414 (- (max (min desired-height max-height)
415 (or min-height window-min-height))
417 ;; We do our own height checking, so avoid any restrictions due to
418 ;; window-min-height.
419 (window-min-height 1))
421 ;; Don't try to redisplay with the cursor at the end
422 ;; on its own line--that would force a scroll and spoil things.
423 (when (with-current-buffer buf
424 (and (eobp) (bolp) (not (bobp))))
425 (set-window-point window (1- (window-point window))))
427 (save-selected-window
428 (select-window window)
430 ;; Adjust WINDOW to the nominally correct size (which may actually
431 ;; be slightly off because of variable height text, etc).
432 (unless (zerop delta)
433 (enlarge-window delta))
435 ;; Check if the last line is surely fully visible. If not,
436 ;; enlarge the window.
437 (let ((end (with-current-buffer buf
439 (goto-char (point-max))
440 (when (and (bolp) (not (bobp)))
441 ;; Don't include final newline
444 ;; If line-wrapping is turned off, test the
445 ;; beginning of the last line for visibility
446 ;; instead of the end, as the end of the line
447 ;; could be invisible by virtue of extending past
448 ;; the edge of the window.
451 (set-window-vscroll window 0)
452 (while (and (< desired-height max-height)
453 (= desired-height (window-height window))
454 (not (pos-visible-in-window-p end window)))
456 (setq desired-height (1+ desired-height)))))))
458 (defun shrink-window-if-larger-than-buffer (&optional window)
459 "Shrink the WINDOW to be as small as possible to display its contents.
460 If WINDOW is omitted or nil, it defaults to the selected window.
461 Do not shrink to less than `window-min-height' lines.
462 Do nothing if the buffer contains more lines than the present window height,
463 or if some of the window's contents are scrolled out of view,
464 or if shrinking this window would also shrink another window.
465 or if the window is the only window of its frame.
466 Return non-nil if the window was shrunk."
469 (setq window (selected-window)))
470 (let* ((frame (window-frame window))
471 (mini (frame-parameter frame 'minibuffer))
472 (edges (window-edges window)))
473 (if (and (not (eq window (frame-root-window frame)))
474 (window-safely-shrinkable-p)
475 (pos-visible-in-window-p (point-min) window)
476 (not (eq mini 'only))
478 (let ((mini-window (minibuffer-window frame)))
479 (or (null mini-window)
480 (not (eq frame (window-frame mini-window)))
482 (nth 1 (window-edges mini-window)))
484 (frame-parameter frame 'menu-bar-lines))))))
485 (fit-window-to-buffer window (window-height window)))))
487 (defun kill-buffer-and-window ()
488 "Kill the current buffer and delete the selected window."
490 (if (yes-or-no-p (format "Kill buffer `%s'? " (buffer-name)))
491 (let ((buffer (current-buffer)))
492 (delete-window (selected-window))
493 (kill-buffer buffer))
496 (defun quit-window (&optional kill window)
497 "Quit the current buffer. Bury it, and maybe delete the selected frame.
498 \(The frame is deleted if it is contains a dedicated window for the buffer.)
499 With a prefix argument, kill the buffer instead.
501 Noninteractively, if KILL is non-nil, then kill the current buffer,
504 If WINDOW is non-nil, it specifies a window; we delete that window,
505 and the buffer that is killed or buried is the one in that window."
507 (let ((buffer (window-buffer window))
508 (frame (window-frame (or window (selected-window))))
510 (save-selected-window
512 (select-window window))
516 (save-selected-window
518 (select-window window))
519 (or (window-minibuffer-p)
520 (window-dedicated-p (selected-window))
521 (switch-to-buffer (other-buffer))))
523 ;; Get rid of the frame, if it has just one dedicated window
524 ;; and other visible frames exist.
525 (and (or (window-minibuffer-p) (window-dedicated-p window))
526 (delq frame (visible-frame-list))
528 (if (and (eq default-minibuffer-frame frame)
529 (= 1 (length (minibuffer-frame-list))))
532 (setq window-handled t)))
534 ;; Deal with the buffer.
537 (bury-buffer buffer))
539 ;; Maybe get rid of the window.
540 (and window (not window-handled) (not window-solitary)
541 (delete-window window))))
543 (define-key ctl-x-map "2" 'split-window-vertically)
544 (define-key ctl-x-map "3" 'split-window-horizontally)
545 (define-key ctl-x-map "}" 'enlarge-window-horizontally)
546 (define-key ctl-x-map "{" 'shrink-window-horizontally)
547 (define-key ctl-x-map "-" 'shrink-window-if-larger-than-buffer)
548 (define-key ctl-x-map "+" 'balance-windows)
549 (define-key ctl-x-4-map "0" 'kill-buffer-and-window)
551 ;;; window.el ends here