summaryrefslogtreecommitdiff
path: root/lisp/window.el
blob: 0b55ccbe9a3329dd6508fe9384be801095d38dd0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
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
;;; window.el --- GNU Emacs window commands aside from those written in C.

;; Copyright (C) 1985, 1989, 1992, 1993, 1994 Free Software Foundation, Inc.

;; Maintainer: FSF

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Code:

;;;; Window tree functions.

(defun one-window-p (&optional nomini all-frames)
  "Returns non-nil if the selected window is the only window (in its frame).
Optional arg NOMINI non-nil means don't count the minibuffer
even if it is active.

The optional arg ALL-FRAMES t means count windows on all frames.
If it is `visible', count windows on all visible frames.
ALL-FRAMES nil or omitted means count only the selected frame, 
plus the minibuffer it uses (which may be on another frame).
If ALL-FRAMES is neither nil nor t, count only the selected frame."
  (let ((base-window (selected-window)))
    (if (and nomini (eq base-window (minibuffer-window)))
	(setq base-window (next-window base-window)))
    (eq base-window
	(next-window base-window (if nomini 'arg) all-frames))))

(defun 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
if not active.  MINIBUF nil or omitted means count the minibuffer iff
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.
Anything else means restrict to the selected frame."
  ;; If we start from the minibuffer window, don't fail to come back to it.
  (if (window-minibuffer-p (selected-window))
      (setq minibuf t))
  (let* ((walk-windows-start (selected-window))
	 (walk-windows-current walk-windows-start))
    (while (progn
	     (setq walk-windows-current
		   (next-window walk-windows-current minibuf all-frames))
	     (funcall proc walk-windows-current)
	     (not (eq walk-windows-current walk-windows-start))))))

(defun minibuffer-window-active-p (window)
  "Return t if WINDOW (a minibuffer window) is now active."
  (eq window (active-minibuffer-window)))

(defmacro save-selected-window (&rest body)
  "Execute BODY, then select the window that was selected before BODY."
  (list 'let
	'((save-selected-window-window (selected-window)))
	(list 'unwind-protect
	      (cons 'progn body)
	      (list 'select-window 'save-selected-window-window)))) 

(defun count-windows (&optional minibuf)
   "Returns the number of visible windows.
Optional arg MINIBUF non-nil means count the minibuffer
even if it is inactive."
   (let ((count 0))
     (walk-windows (function (lambda (w)
			       (setq count (+ count 1))))
		   minibuf)
     count))

(defun balance-windows ()
  "Makes all visible windows the same height (approximately)."
  (interactive)
  (let ((count -1) levels newsizes size
	;; Don't count the lines that are above the uppermost windows.
	;; (These are the menu bar lines, if any.)
	(mbl (nth 1 (window-edges (frame-first-window (selected-frame))))))
    ;; Find all the different vpos's at which windows start,
    ;; then count them.  But ignore levels that differ by only 1.
    (save-window-excursion
      (let (tops (prev-top -2))
	(walk-windows (function (lambda (w)
				  (setq tops (cons (nth 1 (window-edges w))
						   tops))))
		      'nomini)
	(setq tops (sort tops '<))
	(while tops
	  (if (> (car tops) (1+ prev-top))
	      (setq prev-top (car tops)
		    count (1+ count)))
	  (setq levels (cons (cons (car tops) count) levels))
	  (setq tops (cdr tops)))
	(setq count (1+ count))))
    ;; Subdivide the frame into that many vertical levels.
    (setq size (/ (- (frame-height) mbl) count))
    (walk-windows (function
		   (lambda (w)
		     (select-window w)
		     (let ((newtop (cdr (assq (nth 1 (window-edges))
					      levels)))
			   (newbot (or (cdr (assq (+ (window-height)
						     (nth 1 (window-edges)))
						  levels))
				       count)))
		       (setq newsizes
			     (cons (cons w (* size (- newbot newtop)))
				   newsizes)))))
		  'nomini)
    (walk-windows (function (lambda (w)
			      (select-window w)
			      (let ((newsize (cdr (assq w newsizes))))
				(enlarge-window (- newsize
						   (window-height))))))
		  'nomini)))

;;; I think this should be the default; I think people will prefer it--rms.
(defvar split-window-keep-point t
  "*If non-nil, split windows keeps the original point in both children.
This is often more convenient for editing.
If nil, adjust point in each of the two windows to minimize redisplay.
This is convenient on slow terminals, but point can move strangely.")

(defun split-window-vertically (&optional arg)
  "Split current window into two windows, one above the other.
The uppermost window gets ARG lines and the other gets the rest.
Negative arg means select the size of the lowermost window instead.
With no argument, split equally or close to it.
Both windows display the same buffer now current.

If the variable split-window-keep-point is non-nil, both new windows
will get the same value of point as the current window.  This is often
more convenient for editing.

Otherwise, we chose window starts so as to minimize the amount of
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
new mode line."
  (interactive "P")
  (let ((old-w (selected-window))
	(old-point (point))
	(size (and arg (prefix-numeric-value arg)))
        (window-full-p nil)
	new-w bottom switch moved)
    (and size (< size 0) (setq size (+ (window-height) size)))
    (setq new-w (split-window nil size))
    (or split-window-keep-point
	(progn
	  (save-excursion
	    (set-buffer (window-buffer))
	    (goto-char (window-start))
            (setq moved (vertical-motion (window-height)))
	    (set-window-start new-w (point))
	    (if (> (point) (window-point new-w))
		(set-window-point new-w (point)))
            (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)))))
    new-w))

(defun split-window-horizontally (&optional arg)
  "Split current window into two windows side by side.
This window becomes the leftmost of the two, and gets ARG columns.
Negative arg means select the size of the rightmost window instead.
No arg means split equally."
  (interactive "P")
  (let ((size (and arg (prefix-numeric-value arg))))
    (and size (< size 0)
	 (setq size (+ (window-width) size)))
    (split-window nil size t)))

(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))

(defun shrink-window-if-larger-than-buffer (&optional window)
  "Shrink the WINDOW to be as small as possible to display its contents.
Do not shrink to less than `window-min-height' lines.
Do nothing if the buffer contains more lines than the present window height,
or if some of the window's contents are scrolled out of view,
or if the window is not the full width of the frame,
or if the window is the only window of its frame."
  (interactive)
  (or window (setq window (selected-window)))
  (save-excursion
    (set-buffer (window-buffer window))
    (let* ((w (selected-window))	;save-window-excursion can't win
	   (buffer-file-name buffer-file-name)
	   (p (point))
	   (n 0)
	   (ignore-final-newline
	    ;; If buffer ends with a newline, ignore it when counting height
	    ;; unless point is after it.
	    (and (not (eobp))
		 (eq ?\n (char-after (1- (point-max))))))
	   (buffer-read-only nil)
	   (modified (buffer-modified-p))
	   (buffer (current-buffer))
	   (params (frame-parameters (window-frame window)))
	   (mini (cdr (assq 'minibuffer params)))
	   (edges (window-edges (selected-window))))
      (if (and (< 1 (let ((frame (selected-frame)))
		      (select-frame (window-frame window))
		      (unwind-protect
			  (count-windows)
			(select-frame frame))))
	       (= (window-width window) (frame-width (window-frame window)))
	       (pos-visible-in-window-p (point-min) window)
	       (not (eq mini 'only))
	       (or (not mini)
		   (< (nth 3 edges)
		      (nth 1 (window-edges mini)))
		   (> (nth 1 edges)
		      (cdr (assq 'menu-bar-lines params)))))
	  (unwind-protect
	      (progn
		(select-window (or window w))
		(goto-char (point-min))
		(while (pos-visible-in-window-p
			(- (point-max)
			   (if ignore-final-newline 1 0)))
		  ;; defeat file locking... don't try this at home, kids!
		  (setq buffer-file-name nil)
		  (insert ?\n) (setq n (1+ n)))
		(if (> n 0)
		    (shrink-window (min (1- n)
					(- (window-height)
					   window-min-height)))))
	    (delete-region (point-min) (point))
	    (set-buffer-modified-p modified)
	    (goto-char p)
	    (select-window w)
	    ;; Make sure we unbind buffer-read-only
	    ;; with the proper current buffer.
	    (set-buffer buffer))))))

(defun kill-buffer-and-window ()
  "Kill the current buffer and delete the selected window."
  (interactive)
  (if (yes-or-no-p (format "Kill buffer `%s'? " (buffer-name)))
      (let ((buffer (current-buffer)))
	(delete-window (selected-window))
	(kill-buffer buffer))
    (error "Aborted")))

(define-key ctl-x-map "2" 'split-window-vertically)
(define-key ctl-x-map "3" 'split-window-horizontally)
(define-key ctl-x-map "}" 'enlarge-window-horizontally)
(define-key ctl-x-map "{" 'shrink-window-horizontally)
(define-key ctl-x-map "-" 'shrink-window-if-larger-than-buffer)
(define-key ctl-x-map "+" 'balance-windows)
(define-key ctl-x-4-map "0" 'kill-buffer-and-window)

;;; windows.el ends here