Mercurial > hg > xemacs-beta
annotate man/lispref/windows.texi @ 5214:0b4d355771bd
Import buffer-display-count, buffer-display-time; thank you, Jeff Sparkes.
man/ChangeLog addition:
2010-05-17 Jeff Sparkes <jsparkes@gmail.com>
* lispref/windows.texi (Buffers and Windows):
Document buffer-display-count and buffer-display-time with
descriptions from GNU emacs lispref.
* lispref/locals.texi (Standard Buffer-Local Variables):
Add buffer-display-count and buffer-display-time.
src/ChangeLog addition:
2010-05-17 Jeff Sparkes <jsparkes@gmail.com>
* buffer.c (complex_vars_of_buffer):
Add buffer local variables buffer-display-count and
buffer-display-time.
(common_init_complex_vars_of_buffer):
Initialize them here.
* bufslots.h: Add slots for buffer-display-count and buffer-display-time.
* window.c (Fset_window_buffer): Update buffer-display-count and
buffer-display-time whenever a buffer is displayed.
| author | Aidan Kehoe <kehoea@parhasard.net> |
|---|---|
| date | Fri, 28 May 2010 13:48:22 +0100 |
| parents | 755ae5b97edb |
| children | 956d54c39176 |
| rev | line source |
|---|---|
| 428 | 1 @c -*-texinfo-*- |
| 2 @c This is part of the XEmacs Lisp Reference Manual. | |
| 444 | 3 @c Copyright (C) 1990, 1991, 1992, 1993, 1994 Free Software Foundation, Inc. |
| 428 | 4 @c See the file lispref.texi for copying conditions. |
| 5 @setfilename ../../info/windows.info | |
| 6 @node Windows, Frames, Buffers, Top | |
| 7 @chapter Windows | |
| 8 | |
| 9 This chapter describes most of the functions and variables related to | |
| 10 Emacs windows. See @ref{Display}, for information on how text is | |
| 11 displayed in windows. | |
| 12 | |
| 13 @menu | |
| 14 * Basic Windows:: Basic information on using windows. | |
| 15 * Splitting Windows:: Splitting one window into two windows. | |
| 16 * Deleting Windows:: Deleting a window gives its space to other windows. | |
| 17 * Selecting Windows:: The selected window is the one that you edit in. | |
| 18 * Cyclic Window Ordering:: Moving around the existing windows. | |
| 19 * Buffers and Windows:: Each window displays the contents of a buffer. | |
| 20 * Displaying Buffers:: Higher-lever functions for displaying a buffer | |
| 21 and choosing a window for it. | |
| 22 * Choosing Window:: How to choose a window for displaying a buffer. | |
| 23 * Window Point:: Each window has its own location of point. | |
| 24 * Window Start:: The display-start position controls which text | |
| 444 | 25 is on-screen in the window. |
| 428 | 26 * Vertical Scrolling:: Moving text up and down in the window. |
| 27 * Horizontal Scrolling:: Moving text sideways on the window. | |
| 28 * Size of Window:: Accessing the size of a window. | |
| 29 * Position of Window:: Accessing the position of a window. | |
| 30 * Resizing Windows:: Changing the size of a window. | |
| 31 * Window Configurations:: Saving and restoring the state of the screen. | |
| 32 @end menu | |
| 33 | |
| 34 @node Basic Windows | |
| 35 @section Basic Concepts of Emacs Windows | |
| 36 @cindex window | |
| 37 @cindex selected window | |
| 38 | |
| 39 A @dfn{window} in XEmacs is the physical area of the screen in which a | |
| 40 buffer is displayed. The term is also used to refer to a Lisp object that | |
| 41 represents that screen area in XEmacs Lisp. It should be | |
| 42 clear from the context which is meant. | |
| 43 | |
| 44 XEmacs groups windows into frames. A frame represents an area of | |
| 45 screen available for XEmacs to use. Each frame always contains at least | |
| 46 one window, but you can subdivide it vertically or horizontally into | |
| 47 multiple nonoverlapping Emacs windows. | |
| 48 | |
| 49 In each frame, at any time, one and only one window is designated as | |
| 50 @dfn{selected within the frame}. The frame's cursor appears in that | |
| 2355 | 51 window. At any time, one frame is the selected frame; and the window |
| 428 | 52 selected within that frame is @dfn{the selected window}. The selected |
| 53 window's buffer is usually the current buffer (except when | |
| 54 @code{set-buffer} has been used). @xref{Current Buffer}. | |
| 55 | |
| 56 For practical purposes, a window exists only while it is displayed in | |
| 57 a frame. Once removed from the frame, the window is effectively deleted | |
| 58 and should not be used, @emph{even though there may still be references | |
| 59 to it} from other Lisp objects. Restoring a saved window configuration | |
| 60 is the only way for a window no longer on the screen to come back to | |
| 61 life. (@xref{Deleting Windows}.) | |
| 62 | |
| 63 Each window has the following attributes: | |
| 64 | |
| 65 @itemize @bullet | |
| 66 @item | |
| 67 containing frame | |
| 68 | |
| 444 | 69 @item |
| 428 | 70 window height |
| 71 | |
| 444 | 72 @item |
| 428 | 73 window width |
| 74 | |
| 444 | 75 @item |
| 428 | 76 window edges with respect to the frame or screen |
| 77 | |
| 444 | 78 @item |
| 428 | 79 the buffer it displays |
| 80 | |
| 444 | 81 @item |
| 428 | 82 position within the buffer at the upper left of the window |
| 83 | |
| 444 | 84 @item |
| 428 | 85 amount of horizontal scrolling, in columns |
| 86 | |
| 444 | 87 @item |
| 428 | 88 point |
| 89 | |
| 444 | 90 @item |
| 428 | 91 the mark |
| 92 | |
| 444 | 93 @item |
| 428 | 94 how recently the window was selected |
| 95 @end itemize | |
| 96 | |
| 97 @cindex multiple windows | |
| 98 Users create multiple windows so they can look at several buffers at | |
| 99 once. Lisp libraries use multiple windows for a variety of reasons, but | |
| 100 most often to display related information. In Rmail, for example, you | |
| 101 can move through a summary buffer in one window while the other window | |
| 102 shows messages one at a time as they are reached. | |
| 103 | |
| 104 The meaning of ``window'' in XEmacs is similar to what it means in the | |
| 105 context of general-purpose window systems such as X, but not identical. | |
| 106 The X Window System places X windows on the screen; XEmacs uses one or | |
| 107 more X windows as frames, and subdivides them into | |
| 108 Emacs windows. When you use XEmacs on a character-only terminal, XEmacs | |
| 109 treats the whole terminal screen as one frame. | |
| 110 | |
| 111 @cindex terminal frame | |
| 112 @cindex frame of terminal | |
| 113 @cindex tiled windows | |
| 114 Most window systems support arbitrarily located overlapping windows. | |
| 115 In contrast, Emacs windows are @dfn{tiled}; they never overlap, and | |
| 116 together they fill the whole screen or frame. Because of the way | |
| 117 in which XEmacs creates new windows and resizes them, you can't create | |
| 118 every conceivable tiling of windows on an Emacs frame. @xref{Splitting | |
| 119 Windows}, and @ref{Size of Window}. | |
| 120 | |
| 121 @xref{Display}, for information on how the contents of the | |
| 122 window's buffer are displayed in the window. | |
| 123 | |
| 124 @defun windowp object | |
| 125 This function returns @code{t} if @var{object} is a window. | |
| 126 @end defun | |
| 127 | |
| 128 @node Splitting Windows | |
| 129 @section Splitting Windows | |
| 130 @cindex splitting windows | |
| 131 @cindex window splitting | |
| 132 | |
| 133 The functions described here are the primitives used to split a window | |
| 134 into two windows. Two higher level functions sometimes split a window, | |
| 135 but not always: @code{pop-to-buffer} and @code{display-buffer} | |
| 136 (@pxref{Displaying Buffers}). | |
| 137 | |
| 138 The functions described here do not accept a buffer as an argument. | |
| 139 The two ``halves'' of the split window initially display the same buffer | |
| 140 previously visible in the window that was split. | |
| 141 | |
| 444 | 142 @defun one-window-p &optional nomini which-frames which-devices |
| 428 | 143 This function returns non-@code{nil} if there is only one window. The |
| 444 | 144 argument @var{nomini}, if non-@code{nil}, means don't count the |
| 428 | 145 minibuffer even if it is active; otherwise, the minibuffer window is |
| 146 included, if active, in the total number of windows which is compared | |
| 147 against one. | |
| 148 | |
| 444 | 149 The remaining arguments controls which set of windows are counted, as |
| 150 with @code{next-window}. | |
| 428 | 151 @end defun |
| 152 | |
| 153 @deffn Command split-window &optional window size horizontal | |
| 154 This function splits @var{window} into two windows. The original | |
| 155 window @var{window} remains the selected window, but occupies only | |
| 156 part of its former screen area. The rest is occupied by a newly created | |
| 157 window which is returned as the value of this function. | |
| 158 | |
| 159 If @var{horizontal} is non-@code{nil}, then @var{window} splits into | |
| 160 two side by side windows. The original window @var{window} keeps the | |
| 161 leftmost @var{size} columns, and gives the rest of the columns to the | |
| 162 new window. Otherwise, it splits into windows one above the other, and | |
| 163 @var{window} keeps the upper @var{size} lines and gives the rest of the | |
| 164 lines to the new window. The original window is therefore the | |
| 165 left-hand or upper of the two, and the new window is the right-hand or | |
| 166 lower. | |
| 167 | |
| 168 If @var{window} is omitted or @code{nil}, then the selected window is | |
| 169 split. If @var{size} is omitted or @code{nil}, then @var{window} is | |
| 170 divided evenly into two parts. (If there is an odd line, it is | |
| 171 allocated to the new window.) When @code{split-window} is called | |
| 172 interactively, all its arguments are @code{nil}. | |
| 173 | |
| 174 The following example starts with one window on a frame that is 50 | |
| 175 lines high by 80 columns wide; then the window is split. | |
| 176 | |
| 177 @smallexample | |
| 178 @group | |
| 179 (setq w (selected-window)) | |
| 180 @result{} #<window 8 on windows.texi> | |
| 181 (window-edges) ; @r{Edges in order:} | |
| 182 @result{} (0 0 80 50) ; @r{left--top--right--bottom} | |
| 183 @end group | |
| 184 | |
| 185 @group | |
| 186 ;; @r{Returns window created} | |
| 444 | 187 (setq w2 (split-window w 15)) |
| 428 | 188 @result{} #<window 28 on windows.texi> |
| 189 @end group | |
| 190 @group | |
| 191 (window-edges w2) | |
| 192 @result{} (0 15 80 50) ; @r{Bottom window;} | |
| 193 ; @r{top is line 15} | |
| 194 @end group | |
| 195 @group | |
| 196 (window-edges w) | |
| 197 @result{} (0 0 80 15) ; @r{Top window} | |
| 198 @end group | |
| 199 @end smallexample | |
| 200 | |
| 201 The frame looks like this: | |
| 202 | |
| 203 @smallexample | |
| 204 @group | |
| 444 | 205 __________ |
| 206 | | line 0 | |
| 428 | 207 | w | |
| 208 |__________| | |
| 209 | | line 15 | |
| 210 | w2 | | |
| 211 |__________| | |
| 212 line 50 | |
| 213 column 0 column 80 | |
| 214 @end group | |
| 215 @end smallexample | |
| 216 | |
| 217 Next, the top window is split horizontally: | |
| 218 | |
| 219 @smallexample | |
| 220 @group | |
| 221 (setq w3 (split-window w 35 t)) | |
| 222 @result{} #<window 32 on windows.texi> | |
| 223 @end group | |
| 224 @group | |
| 225 (window-edges w3) | |
| 226 @result{} (35 0 80 15) ; @r{Left edge at column 35} | |
| 227 @end group | |
| 228 @group | |
| 229 (window-edges w) | |
| 230 @result{} (0 0 35 15) ; @r{Right edge at column 35} | |
| 231 @end group | |
| 232 @group | |
| 233 (window-edges w2) | |
| 234 @result{} (0 15 80 50) ; @r{Bottom window unchanged} | |
| 235 @end group | |
| 236 @end smallexample | |
| 237 | |
| 238 @need 3000 | |
| 239 Now, the screen looks like this: | |
| 240 | |
| 241 @smallexample | |
| 242 @group | |
| 243 column 35 | |
| 444 | 244 __________ |
| 245 | | | line 0 | |
| 428 | 246 | w | w3 | |
| 247 |___|______| | |
| 248 | | line 15 | |
| 249 | w2 | | |
| 250 |__________| | |
| 251 line 50 | |
| 252 column 0 column 80 | |
| 253 @end group | |
| 254 @end smallexample | |
| 255 | |
| 256 Normally, Emacs indicates the border between two side-by-side windows | |
| 257 with a scroll bar (@pxref{X Frame Properties,Scroll Bars}) or @samp{|} | |
| 258 characters. The display table can specify alternative border | |
| 259 characters; see @ref{Display Tables}. | |
| 260 @end deffn | |
| 261 | |
| 262 @deffn Command split-window-vertically &optional size | |
| 263 This function splits the selected window into two windows, one above | |
| 264 the other, leaving the selected window with @var{size} lines. | |
| 265 | |
| 444 | 266 This function is simply an interface to @code{split-window}. |
| 428 | 267 Here is the complete function definition for it: |
| 268 | |
| 269 @smallexample | |
| 270 @group | |
| 271 (defun split-window-vertically (&optional arg) | |
| 272 "Split current window into two windows, one above the other." | |
| 273 (interactive "P") | |
| 274 (split-window nil (and arg (prefix-numeric-value arg)))) | |
| 275 @end group | |
| 276 @end smallexample | |
| 277 @end deffn | |
| 278 | |
| 279 @deffn Command split-window-horizontally &optional size | |
| 280 This function splits the selected window into two windows | |
| 281 side-by-side, leaving the selected window with @var{size} columns. | |
| 282 | |
| 444 | 283 This function is simply an interface to @code{split-window}. Here is |
| 428 | 284 the complete definition for @code{split-window-horizontally} (except for |
| 285 part of the documentation string): | |
| 286 | |
| 287 @smallexample | |
| 288 @group | |
| 289 (defun split-window-horizontally (&optional arg) | |
| 290 "Split selected window into two windows, side by side..." | |
| 291 (interactive "P") | |
| 292 (split-window nil (and arg (prefix-numeric-value arg)) t)) | |
| 293 @end group | |
| 294 @end smallexample | |
| 295 @end deffn | |
| 296 | |
| 297 @node Deleting Windows | |
| 298 @section Deleting Windows | |
| 299 @cindex deleting windows | |
| 300 | |
| 301 A window remains visible on its frame unless you @dfn{delete} it by | |
| 302 calling certain functions that delete windows. A deleted window cannot | |
| 303 appear on the screen, but continues to exist as a Lisp object until | |
| 304 there are no references to it. There is no way to cancel the deletion | |
| 305 of a window aside from restoring a saved window configuration | |
| 306 (@pxref{Window Configurations}). Restoring a window configuration also | |
| 307 deletes any windows that aren't part of that configuration. | |
| 308 | |
| 309 When you delete a window, the space it took up is given to one | |
| 310 adjacent sibling. (In Emacs version 18, the space was divided evenly | |
| 311 among all the siblings.) | |
| 312 | |
| 313 @c Emacs 19 feature | |
| 314 @defun window-live-p window | |
| 315 This function returns @code{nil} if @var{window} is deleted, and | |
| 316 @code{t} otherwise. | |
| 317 | |
| 318 @strong{Warning:} Erroneous information or fatal errors may result from | |
| 319 using a deleted window as if it were live. | |
| 320 @end defun | |
| 321 | |
| 444 | 322 @deffn Command delete-window &optional window force |
| 323 This function removes @var{window} from the display. If @var{window} is | |
| 324 omitted, then the selected window is deleted. If window is the only one | |
| 325 on its frame, the frame is deleted as well. | |
| 326 | |
| 327 Normally, you cannot delete the last non-minibuffer-only frame (you must | |
| 328 use @code{save-buffers-kill-emacs} or @code{kill-emacs}); an error is | |
| 329 signaled instead. However, if optional second argument @var{force} is | |
| 330 non-@code{nil}, you can delete the last frame. (This will automatically | |
| 331 call @code{save-buffers-kill-emacs}.) | |
| 428 | 332 |
| 333 This function returns @code{nil}. | |
| 334 | |
| 444 | 335 When @code{delete-window} is called interactively, the selected window |
| 336 is deleted. | |
| 428 | 337 @end deffn |
| 338 | |
| 339 @deffn Command delete-other-windows &optional window | |
| 340 This function makes @var{window} the only window on its frame, by | |
| 341 deleting the other windows in that frame. If @var{window} is omitted or | |
| 342 @code{nil}, then the selected window is used by default. | |
| 343 | |
| 344 The result is @code{nil}. | |
| 345 @end deffn | |
| 346 | |
| 444 | 347 @deffn Command delete-windows-on buffer &optional which-frames which-devices |
| 428 | 348 This function deletes all windows showing @var{buffer}. If there are |
| 349 no windows showing @var{buffer}, it does nothing. | |
| 350 | |
| 351 @code{delete-windows-on} operates frame by frame. If a frame has | |
| 352 several windows showing different buffers, then those showing | |
| 353 @var{buffer} are removed, and the others expand to fill the space. If | |
| 354 all windows in some frame are showing @var{buffer} (including the case | |
| 355 where there is only one window), then the frame reverts to having a | |
| 356 single window showing another buffer chosen with @code{other-buffer}. | |
| 357 @xref{The Buffer List}. | |
| 358 | |
| 444 | 359 The argument @var{which-frames} controls which frames to operate on: |
| 360 | |
| 361 @table @asis | |
| 362 @item @code{nil} | |
| 363 Delete all windows showing @var{buffer} in any frame. | |
| 364 | |
| 365 @item @code{t} | |
| 366 Delete only windows showing @var{buffer} in the selected frame. | |
| 367 | |
| 368 @item @code{visible} | |
| 369 Delete all windows showing @var{buffer} in any visible frame. | |
| 370 | |
| 371 @item @code{0} | |
| 372 Delete all windows showing @var{buffer} in any visible frame. | |
| 373 | |
| 374 @item @var{frame} | |
| 375 If it is a frame, delete all windows showing @var{buffer} in that frame. | |
| 376 @end table | |
| 377 | |
| 378 @strong{Warning:} This is similar to, but not identical to, the meaning | |
| 379 of the @var{which-frames} argument to @code{next-window}; the meanings | |
| 380 of @code{nil} and @code{t} are reversed. | |
| 428 | 381 |
| 444 | 382 The optional argument @var{which-devices} further clarifies on which |
| 383 devices to search for frames as specified by @var{which-frames}. | |
| 384 This value is only meaningful if @var{which-frames} is not @code{t}. | |
| 385 | |
| 386 @table @asis | |
| 387 @item @code{nil} | |
| 388 Consider all devices on the selected console. | |
| 389 | |
| 390 @item @var{device} | |
| 391 Consider only the one device @var{device}. | |
| 392 | |
| 393 @item @var{console} | |
| 394 Consider all devices on @var{console}. | |
| 395 | |
| 396 @item @var{device-type} | |
| 397 Consider all devices with device type @var{device-type}. | |
| 398 | |
| 399 @item @code{window-system} | |
| 400 Consider all devices on window system consoles. | |
| 401 | |
| 402 @item anything else | |
| 403 Consider all devices without restriction. | |
| 404 @end table | |
| 428 | 405 |
| 406 This function always returns @code{nil}. | |
| 407 @end deffn | |
| 408 | |
| 409 @node Selecting Windows | |
| 410 @section Selecting Windows | |
| 411 @cindex selecting windows | |
| 412 | |
| 413 When a window is selected, the buffer in the window becomes the current | |
| 414 buffer, and the cursor will appear in it. | |
| 415 | |
| 416 @defun selected-window &optional device | |
| 417 This function returns the selected window. This is the window in | |
| 418 which the cursor appears and to which many commands apply. Each | |
| 419 separate device can have its own selected window, which is remembered | |
| 420 as focus changes from device to device. Optional argument @var{device} | |
| 421 specifies which device to return the selected window for, and defaults | |
| 422 to the selected device. | |
| 423 @end defun | |
| 424 | |
| 425 @defun select-window window &optional norecord | |
| 426 This function makes @var{window} the selected window. The cursor then | |
| 427 appears in @var{window} (on redisplay). The buffer being displayed in | |
| 428 @var{window} is immediately designated the current buffer. | |
| 429 | |
| 430 If optional argument @var{norecord} is non-@code{nil} then the global | |
| 431 and per-frame buffer orderings are not modified, as by the function | |
| 444 | 432 @code{record-buffer}. |
| 428 | 433 |
| 434 The return value is @var{window}. | |
| 435 | |
| 436 @example | |
| 437 @group | |
| 438 (setq w (next-window)) | |
| 439 (select-window w) | |
| 440 @result{} #<window 65 on windows.texi> | |
| 441 @end group | |
| 442 @end example | |
| 443 @end defun | |
| 444 | |
| 444 | 445 @defspec save-selected-window forms@dots{} |
|
4905
755ae5b97edb
Change "special form" to "special operator" in our sources.
Aidan Kehoe <kehoea@parhasard.net>
parents:
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diff
changeset
|
446 This macro records the selected window, executes @var{forms} in |
| 444 | 447 sequence, then restores the earlier selected window. It does not save |
| 448 or restore anything about the sizes, arrangement or contents of windows; | |
| 449 therefore, if the @var{forms} change them, the changes are permanent. | |
| 450 @end defspec | |
| 428 | 451 |
| 452 @cindex finding windows | |
| 453 The following functions choose one of the windows on the screen, | |
| 454 offering various criteria for the choice. | |
| 455 | |
| 444 | 456 @defun get-lru-window &optional which-frames which-devices |
| 428 | 457 This function returns the window least recently ``used'' (that is, |
| 458 selected). The selected window is always the most recently used window. | |
| 459 | |
| 460 The selected window can be the least recently used window if it is the | |
| 461 only window. A newly created window becomes the least recently used | |
| 462 window until it is selected. A minibuffer window is never a candidate. | |
| 463 | |
| 444 | 464 By default, only the windows in the selected frame are considered. |
| 465 The optional argument @var{which-frames} changes this behavior. | |
| 466 Here are the possible values and their meanings: | |
| 467 | |
| 468 @table @asis | |
| 469 @item @code{nil} | |
| 470 Consider all the windows in the selected windows's frame, plus the | |
| 471 minibuffer used by that frame even if it lies in some other frame. | |
| 472 | |
| 473 @item @code{t} | |
| 474 Consider all windows in all existing frames. | |
| 475 | |
| 476 @item @code{visible} | |
| 477 Consider all windows in all visible frames. (To get useful results, you | |
| 478 must ensure @var{window} is in a visible frame.) | |
| 479 | |
| 480 @item @code{0} | |
| 481 Consider all windows in all visible or iconified frames. | |
| 482 | |
| 483 @item @var{frame} | |
| 484 Consider all windows on frame @var{frame}. | |
| 428 | 485 |
| 444 | 486 @item anything else |
| 487 Consider precisely the windows in the selected window's frame, and no others. | |
| 488 @end table | |
| 489 | |
| 490 The optional argument @var{which-devices} further clarifies on which | |
| 491 devices to search for frames as specified by @var{which-frames}. | |
| 492 This value is only meaningful if @var{which-frames} is non-@code{nil}. | |
| 493 | |
| 494 @table @asis | |
| 495 @item @code{nil} | |
| 496 Consider all devices on the selected console. | |
| 497 | |
| 498 @item @var{device} | |
| 499 Consider only the one device @var{device}. | |
| 500 | |
| 501 @item @var{console} | |
| 502 Consider all devices on @var{console}. | |
| 503 | |
| 504 @item @var{device-type} | |
| 505 Consider all devices with device type @var{device-type}. | |
| 506 | |
| 507 @item @code{window-system} | |
| 508 Consider all devices on window system consoles. | |
| 509 | |
| 510 @item anything else | |
| 511 Consider all devices without restriction. | |
| 512 @end table | |
| 513 | |
| 428 | 514 @end defun |
| 515 | |
| 444 | 516 @defun get-largest-window &optional which-frames which-devices |
| 428 | 517 This function returns the window with the largest area (height times |
| 518 width). If there are no side-by-side windows, then this is the window | |
| 519 with the most lines. A minibuffer window is never a candidate. | |
| 520 | |
| 521 If there are two windows of the same size, then the function returns | |
| 522 the window that is first in the cyclic ordering of windows (see | |
| 523 following section), starting from the selected window. | |
| 524 | |
| 444 | 525 The remaining arguments control which set of windows are considered. |
| 526 See @code{next-window}, above. | |
| 428 | 527 @end defun |
| 528 | |
| 529 @node Cyclic Window Ordering | |
| 530 @section Cyclic Ordering of Windows | |
| 531 @cindex cyclic ordering of windows | |
| 532 @cindex ordering of windows, cyclic | |
| 444 | 533 @cindex window ordering, cyclic |
| 428 | 534 |
| 535 When you use the command @kbd{C-x o} (@code{other-window}) to select | |
| 536 the next window, it moves through all the windows on the screen in a | |
| 537 specific cyclic order. For any given configuration of windows, this | |
| 538 order never varies. It is called the @dfn{cyclic ordering of windows}. | |
| 539 | |
| 540 This ordering generally goes from top to bottom, and from left to | |
| 541 right. But it may go down first or go right first, depending on the | |
| 542 order in which the windows were split. | |
| 543 | |
| 544 If the first split was vertical (into windows one above each other), | |
| 545 and then the subwindows were split horizontally, then the ordering is | |
| 546 left to right in the top of the frame, and then left to right in the | |
| 547 next lower part of the frame, and so on. If the first split was | |
| 548 horizontal, the ordering is top to bottom in the left part, and so on. | |
| 549 In general, within each set of siblings at any level in the window tree, | |
| 550 the order is left to right, or top to bottom. | |
| 551 | |
| 444 | 552 @defun next-window &optional window minibuf which-frames which-devices |
| 428 | 553 @cindex minibuffer window |
| 554 This function returns the window following @var{window} in the cyclic | |
| 555 ordering of windows. This is the window that @kbd{C-x o} would select | |
| 556 if typed when @var{window} is selected. If @var{window} is the only | |
| 557 window visible, then this function returns @var{window}. If omitted, | |
| 558 @var{window} defaults to the selected window. | |
| 559 | |
| 560 The value of the argument @var{minibuf} determines whether the | |
| 561 minibuffer is included in the window order. Normally, when | |
| 562 @var{minibuf} is @code{nil}, the minibuffer is included if it is | |
| 563 currently active; this is the behavior of @kbd{C-x o}. (The minibuffer | |
| 564 window is active while the minibuffer is in use. @xref{Minibuffers}.) | |
| 565 | |
| 566 If @var{minibuf} is @code{t}, then the cyclic ordering includes the | |
| 567 minibuffer window even if it is not active. | |
| 568 | |
| 569 If @var{minibuf} is neither @code{t} nor @code{nil}, then the minibuffer | |
| 570 window is not included even if it is active. | |
| 571 | |
| 444 | 572 By default, only the windows in the selected frame are considered. |
| 573 The optional argument @var{which-frames} changes this behavior. | |
| 574 Here are the possible values and their meanings: | |
| 428 | 575 |
| 576 @table @asis | |
| 577 @item @code{nil} | |
| 578 Consider all the windows in @var{window}'s frame, plus the minibuffer | |
| 579 used by that frame even if it lies in some other frame. | |
| 580 | |
| 581 @item @code{t} | |
| 582 Consider all windows in all existing frames. | |
| 583 | |
| 584 @item @code{visible} | |
| 585 Consider all windows in all visible frames. (To get useful results, you | |
| 586 must ensure @var{window} is in a visible frame.) | |
| 587 | |
| 444 | 588 @item @code{0} |
| 428 | 589 Consider all windows in all visible or iconified frames. |
| 590 | |
| 444 | 591 @item @var{frame} |
| 592 Consider all windows on frame @var{frame}. | |
| 593 | |
| 428 | 594 @item anything else |
| 595 Consider precisely the windows in @var{window}'s frame, and no others. | |
| 596 @end table | |
| 597 | |
| 444 | 598 The optional argument @var{which-devices} further clarifies on which |
| 599 devices to search for frames as specified by @var{which-frames}. | |
| 600 This value is only meaningful if @var{which-frames} is non-@code{nil}. | |
| 601 | |
| 602 @table @asis | |
| 603 @item @code{nil} | |
| 604 Consider all devices on the selected console. | |
| 605 | |
| 606 @item @var{device} | |
| 607 Consider only the one device @var{device}. | |
| 608 | |
| 609 @item @var{console} | |
| 610 Consider all devices on @var{console}. | |
| 611 | |
| 612 @item @var{device-type} | |
| 613 Consider all devices with device type @var{device-type}. | |
| 614 | |
| 615 @item @code{window-system} | |
| 616 Consider all devices on window system consoles. | |
| 617 | |
| 618 @item anything else | |
| 619 Consider all devices without restriction. | |
| 620 @end table | |
| 621 | |
| 622 If you use consistent values for @var{minibuf}, @var{which-frames}, and | |
| 623 @var{which-devices}, you can use @code{next-window} to iterate through the | |
| 624 entire cycle of acceptable windows, eventually ending up back at the | |
| 625 window you started with. @code{previous-window} traverses the same | |
| 626 cycle, in the reverse order. | |
| 627 | |
| 628 This example assumes there are two windows, both displaying the | |
| 428 | 629 buffer @samp{windows.texi}: |
| 630 | |
| 631 @example | |
| 632 @group | |
| 633 (selected-window) | |
| 634 @result{} #<window 56 on windows.texi> | |
| 635 @end group | |
| 636 @group | |
| 637 (next-window (selected-window)) | |
| 638 @result{} #<window 52 on windows.texi> | |
| 639 @end group | |
| 640 @group | |
| 641 (next-window (next-window (selected-window))) | |
| 642 @result{} #<window 56 on windows.texi> | |
| 643 @end group | |
| 644 @end example | |
| 645 @end defun | |
| 646 | |
| 444 | 647 @defun previous-window &optional window minibuf which-frames which-devices |
| 428 | 648 This function returns the window preceding @var{window} in the cyclic |
| 649 ordering of windows. The other arguments specify which windows to | |
| 650 include in the cycle, as in @code{next-window}. | |
| 651 @end defun | |
| 652 | |
| 444 | 653 @deffn Command other-window count &optional which-frames which-devices |
| 654 This function selects the @var{count}th following window in the cyclic order. | |
| 655 If @var{count} is negative, then it selects the @minus{}@var{count}th | |
| 428 | 656 preceding window. It returns @code{nil}. |
| 657 | |
| 658 In an interactive call, @var{count} is the numeric prefix argument. | |
| 659 | |
| 444 | 660 The other arguments specify which windows to include in the cycle, as in |
| 661 @code{next-window}. | |
| 428 | 662 @end deffn |
| 663 | |
| 444 | 664 @defun walk-windows function &optional minibuf which-frames which-devices |
| 665 This function cycles through all windows, calling @code{function} | |
| 428 | 666 once for each window with the window as its sole argument. |
| 667 | |
| 444 | 668 The other arguments specify which windows to cycle through, as in |
| 669 @code{next-window}. | |
| 428 | 670 @end defun |
| 671 | |
| 672 @node Buffers and Windows | |
| 673 @section Buffers and Windows | |
| 674 @cindex examining windows | |
| 675 @cindex windows, controlling precisely | |
| 676 @cindex buffers, controlled in windows | |
| 677 | |
| 678 This section describes low-level functions to examine windows or to | |
| 679 display buffers in windows in a precisely controlled fashion. | |
| 680 @iftex | |
| 681 See the following section for | |
| 682 @end iftex | |
| 683 @ifinfo | |
| 684 @xref{Displaying Buffers}, for | |
| 685 @end ifinfo | |
| 686 related functions that find a window to use and specify a buffer for it. | |
| 687 The functions described there are easier to use than these, but they | |
| 688 employ heuristics in choosing or creating a window; use these functions | |
| 689 when you need complete control. | |
| 690 | |
| 444 | 691 @defun set-window-buffer window buffer-or-name &optional norecord |
| 428 | 692 This function makes @var{window} display @var{buffer-or-name} as its |
| 444 | 693 contents. @var{buffer-or-name} can be a buffer or a buffer name. |
| 694 | |
| 695 With non-@code{nil} optional argument @var{norecord}, do not modify the | |
| 696 global or per-frame buffer ordering. | |
| 697 | |
| 698 This function returns @code{nil}. | |
| 428 | 699 |
| 700 @example | |
| 701 @group | |
| 702 (set-window-buffer (selected-window) "foo") | |
| 703 @result{} nil | |
| 704 @end group | |
| 705 @end example | |
| 706 @end defun | |
| 707 | |
|
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708 @defvar buffer-display-count |
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709 This buffer-local variable records the number of times a buffer has been |
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710 displayed in a window. It is incremented each time |
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711 @code{set-window-buffer} is called for the buffer. |
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712 @end defvar |
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713 |
| 428 | 714 @defun window-buffer &optional window |
| 715 This function returns the buffer that @var{window} is displaying. If | |
| 716 @var{window} is omitted, this function returns the buffer for the | |
| 717 selected window. | |
| 718 | |
| 719 @example | |
| 720 @group | |
| 721 (window-buffer) | |
| 722 @result{} #<buffer windows.texi> | |
| 723 @end group | |
| 724 @end example | |
| 725 @end defun | |
| 726 | |
| 444 | 727 @defun get-buffer-window buffer-or-name &optional which-frames which-devices |
| 428 | 728 This function returns a window currently displaying |
| 729 @var{buffer-or-name}, or @code{nil} if there is none. If there are | |
| 730 several such windows, then the function returns the first one in the | |
| 731 cyclic ordering of windows, starting from the selected window. | |
| 732 @xref{Cyclic Window Ordering}. | |
| 733 | |
| 444 | 734 The remaining arguments control which windows to consider. They have |
| 735 the same meaning as for @code{next-window}. | |
| 428 | 736 @end defun |
| 737 | |
|
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738 |
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739 @defvar buffer-display-time |
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740 This variable records the time at which a buffer was last made visible |
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741 in a window. It is always local in each buffer; each time |
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742 @code{set-window-buffer} is called, it sets this variable to |
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743 @code{(current-time)} in the specified buffer (@pxref{Time of Day}). |
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744 When a buffer is first created, @code{buffer-display-time} starts out |
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745 with the value @code{nil}. |
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746 @end defvar |
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747 |
| 428 | 748 @node Displaying Buffers |
| 749 @section Displaying Buffers in Windows | |
| 750 @cindex switching to a buffer | |
| 751 @cindex displaying a buffer | |
| 752 | |
| 753 In this section we describe convenient functions that choose a window | |
| 754 automatically and use it to display a specified buffer. These functions | |
| 755 can also split an existing window in certain circumstances. We also | |
| 756 describe variables that parameterize the heuristics used for choosing a | |
| 757 window. | |
| 758 @iftex | |
| 759 See the preceding section for | |
| 760 @end iftex | |
| 761 @ifinfo | |
| 762 @xref{Buffers and Windows}, for | |
| 763 @end ifinfo | |
| 764 low-level functions that give you more precise control. | |
| 765 | |
| 766 Do not use the functions in this section in order to make a buffer | |
| 767 current so that a Lisp program can access or modify it; they are too | |
| 768 drastic for that purpose, since they change the display of buffers in | |
| 769 windows, which is gratuitous and will surprise the user. Instead, use | |
| 770 @code{set-buffer} (@pxref{Current Buffer}) and @code{save-excursion} | |
| 771 (@pxref{Excursions}), which designate buffers as current for programmed | |
| 772 access without affecting the display of buffers in windows. | |
| 773 | |
| 774 @deffn Command switch-to-buffer buffer-or-name &optional norecord | |
| 775 This function makes @var{buffer-or-name} the current buffer, and also | |
| 776 displays the buffer in the selected window. This means that a human can | |
| 777 see the buffer and subsequent keyboard commands will apply to it. | |
| 778 Contrast this with @code{set-buffer}, which makes @var{buffer-or-name} | |
| 779 the current buffer but does not display it in the selected window. | |
| 780 @xref{Current Buffer}. | |
| 781 | |
| 782 If @var{buffer-or-name} does not identify an existing buffer, then a new | |
| 783 buffer by that name is created. The major mode for the new buffer is | |
| 784 set according to the variable @code{default-major-mode}. @xref{Auto | |
| 785 Major Mode}. | |
| 786 | |
| 787 Normally the specified buffer is put at the front of the buffer list. | |
| 788 This affects the operation of @code{other-buffer}. However, if | |
| 789 @var{norecord} is non-@code{nil}, this is not done. @xref{The Buffer | |
| 790 List}. | |
| 791 | |
| 792 The @code{switch-to-buffer} function is often used interactively, as | |
| 793 the binding of @kbd{C-x b}. It is also used frequently in programs. It | |
| 794 always returns @code{nil}. | |
| 795 @end deffn | |
| 796 | |
| 797 @deffn Command switch-to-buffer-other-window buffer-or-name | |
| 798 This function makes @var{buffer-or-name} the current buffer and | |
| 799 displays it in a window not currently selected. It then selects that | |
| 800 window. The handling of the buffer is the same as in | |
| 801 @code{switch-to-buffer}. | |
| 802 | |
| 803 The currently selected window is absolutely never used to do the job. | |
| 804 If it is the only window, then it is split to make a distinct window for | |
| 805 this purpose. If the selected window is already displaying the buffer, | |
| 806 then it continues to do so, but another window is nonetheless found to | |
| 807 display it in as well. | |
| 808 @end deffn | |
| 809 | |
| 810 @defun pop-to-buffer buffer-or-name &optional other-window on-frame | |
| 811 This function makes @var{buffer-or-name} the current buffer and | |
| 812 switches to it in some window, preferably not the window previously | |
| 813 selected. The ``popped-to'' window becomes the selected window within | |
| 814 its frame. | |
| 815 | |
| 816 If the variable @code{pop-up-frames} is non-@code{nil}, | |
| 817 @code{pop-to-buffer} looks for a window in any visible frame already | |
| 818 displaying the buffer; if there is one, it returns that window and makes | |
| 819 it be selected within its frame. If there is none, it creates a new | |
| 820 frame and displays the buffer in it. | |
| 821 | |
| 822 If @code{pop-up-frames} is @code{nil}, then @code{pop-to-buffer} | |
| 823 operates entirely within the selected frame. (If the selected frame has | |
| 824 just a minibuffer, @code{pop-to-buffer} operates within the most | |
| 825 recently selected frame that was not just a minibuffer.) | |
| 826 | |
| 827 If the variable @code{pop-up-windows} is non-@code{nil}, windows may | |
| 828 be split to create a new window that is different from the original | |
| 829 window. For details, see @ref{Choosing Window}. | |
| 830 | |
| 831 If @var{other-window} is non-@code{nil}, @code{pop-to-buffer} finds or | |
| 832 creates another window even if @var{buffer-or-name} is already visible | |
| 833 in the selected window. Thus @var{buffer-or-name} could end up | |
| 834 displayed in two windows. On the other hand, if @var{buffer-or-name} is | |
| 835 already displayed in the selected window and @var{other-window} is | |
| 836 @code{nil}, then the selected window is considered sufficient display | |
| 837 for @var{buffer-or-name}, so that nothing needs to be done. | |
| 838 | |
| 839 All the variables that affect @code{display-buffer} affect | |
| 840 @code{pop-to-buffer} as well. @xref{Choosing Window}. | |
| 841 | |
| 842 If @var{buffer-or-name} is a string that does not name an existing | |
| 843 buffer, a buffer by that name is created. The major mode for the new | |
| 844 buffer is set according to the variable @code{default-major-mode}. | |
| 845 @xref{Auto Major Mode}. | |
| 846 | |
| 847 If @var{on-frame} is non-@code{nil}, it is the frame to pop to this | |
| 848 buffer on. | |
| 849 | |
| 850 An example use of this function is found at the end of @ref{Filter | |
| 851 Functions}. | |
| 852 @end defun | |
| 853 | |
| 444 | 854 @deffn Command replace-buffer-in-windows buffer &optional which-frames which-devices |
| 428 | 855 This function replaces @var{buffer} with some other buffer in all |
| 856 windows displaying it. The other buffer used is chosen with | |
| 857 @code{other-buffer}. In the usual applications of this function, you | |
| 858 don't care which other buffer is used; you just want to make sure that | |
| 859 @var{buffer} is no longer displayed. | |
| 860 | |
| 444 | 861 The optional arguments @var{which-frames} and @var{which-devices} have |
| 862 the same meaning as with @code{delete-windows-on}. | |
| 863 | |
| 428 | 864 This function returns @code{nil}. |
| 865 @end deffn | |
| 866 | |
| 867 @node Choosing Window | |
| 868 @section Choosing a Window for Display | |
| 869 | |
| 870 This section describes the basic facility that chooses a window to | |
| 871 display a buffer in---@code{display-buffer}. All the higher-level | |
| 872 functions and commands use this subroutine. Here we describe how to use | |
| 873 @code{display-buffer} and how to customize it. | |
| 874 | |
| 444 | 875 @deffn Command display-buffer buffer-or-name &optional not-this-window override-frame |
| 428 | 876 This command makes @var{buffer-or-name} appear in some window, like |
| 877 @code{pop-to-buffer}, but it does not select that window and does not | |
| 878 make the buffer current. The identity of the selected window is | |
| 879 unaltered by this function. | |
| 880 | |
| 444 | 881 @var{buffer-or-name} can be a buffer or the name of one. |
| 882 | |
| 428 | 883 If @var{not-this-window} is non-@code{nil}, it means to display the |
| 884 specified buffer in a window other than the selected one, even if it is | |
| 885 already on display in the selected window. This can cause the buffer to | |
| 886 appear in two windows at once. Otherwise, if @var{buffer-or-name} is | |
| 887 already being displayed in any window, that is good enough, so this | |
| 888 function does nothing. | |
| 889 | |
| 444 | 890 If @var{override-frame} is non-@code{nil}, display on that frame instead |
| 891 of the current frame (or the dedicated frame). | |
| 892 | |
| 893 @code{display-buffer} returns the window chosen to display @var{buffer-or-name}. | |
| 428 | 894 |
| 895 Precisely how @code{display-buffer} finds or creates a window depends on | |
| 896 the variables described below. | |
| 897 @end deffn | |
| 898 | |
| 899 @c Emacs 19 feature | |
| 900 @cindex dedicated window | |
| 901 A window can be marked as ``dedicated'' to a particular buffer. | |
| 902 Then XEmacs will not automatically change which buffer appears in the | |
| 903 window, such as @code{display-buffer} might normally do. | |
| 904 | |
| 905 @defun window-dedicated-p window | |
| 906 This function returns @var{window}'s dedicated object, usually @code{t} | |
| 907 or @code{nil}. | |
| 908 @end defun | |
| 909 | |
| 910 @defun set-window-buffer-dedicated window buffer | |
| 911 This function makes @var{window} display @var{buffer} and be dedicated | |
| 912 to that buffer. Then XEmacs will not automatically change which buffer | |
| 913 appears in @var{window}. If @var{buffer} is @code{nil}, this function makes | |
| 914 @var{window} not be dedicated (but doesn't change which buffer appears | |
| 915 in it currently). | |
| 916 @end defun | |
| 917 | |
| 918 @defopt pop-up-windows | |
| 919 This variable controls whether @code{display-buffer} makes new windows. | |
| 920 If it is non-@code{nil} and there is only one window, then that window | |
| 921 is split. If it is @code{nil}, then @code{display-buffer} does not | |
| 922 split the single window, but uses it whole. | |
| 923 @end defopt | |
| 924 | |
| 925 @defopt split-height-threshold | |
| 926 This variable determines when @code{display-buffer} may split a window, | |
| 927 if there are multiple windows. @code{display-buffer} always splits the | |
| 928 largest window if it has at least this many lines. If the largest | |
| 929 window is not this tall, it is split only if it is the sole window and | |
| 930 @code{pop-up-windows} is non-@code{nil}. | |
| 931 @end defopt | |
| 932 | |
| 933 @c Emacs 19 feature | |
| 934 @defopt pop-up-frames | |
| 935 This variable controls whether @code{display-buffer} makes new frames. | |
| 936 If it is non-@code{nil}, @code{display-buffer} looks for an existing | |
| 937 window already displaying the desired buffer, on any visible frame. If | |
| 938 it finds one, it returns that window. Otherwise it makes a new frame. | |
| 939 The variables @code{pop-up-windows} and @code{split-height-threshold} do | |
| 940 not matter if @code{pop-up-frames} is non-@code{nil}. | |
| 941 | |
| 942 If @code{pop-up-frames} is @code{nil}, then @code{display-buffer} either | |
| 943 splits a window or reuses one. | |
| 944 | |
| 945 @xref{Frames}, for more information. | |
| 946 @end defopt | |
| 947 | |
| 948 @c Emacs 19 feature | |
| 949 @defvar pop-up-frame-function | |
| 950 This variable specifies how to make a new frame if @code{pop-up-frames} | |
| 951 is non-@code{nil}. | |
| 952 | |
| 953 Its value should be a function of no arguments. When | |
| 954 @code{display-buffer} makes a new frame, it does so by calling that | |
| 955 function, which should return a frame. The default value of the | |
| 956 variable is a function that creates a frame using properties from | |
| 957 @code{pop-up-frame-plist}. | |
| 958 @end defvar | |
| 959 | |
| 960 @defvar pop-up-frame-plist | |
| 961 This variable holds a plist specifying frame properties used when | |
| 962 @code{display-buffer} makes a new frame. @xref{Frame Properties}, for | |
| 963 more information about frame properties. | |
| 964 @end defvar | |
| 965 | |
| 966 @defvar special-display-buffer-names | |
| 967 A list of buffer names for buffers that should be displayed specially. | |
| 968 If the buffer's name is in this list, @code{display-buffer} handles the | |
| 969 buffer specially. | |
| 970 | |
| 971 By default, special display means to give the buffer a dedicated frame. | |
| 972 | |
| 973 If an element is a list, instead of a string, then the @sc{car} of the | |
| 974 list is the buffer name, and the rest of the list says how to create the | |
| 975 frame. There are two possibilities for the rest of the list. It can be | |
| 976 a plist, specifying frame properties, or it can contain a function and | |
| 977 arguments to give to it. (The function's first argument is always the | |
| 978 buffer to be displayed; the arguments from the list come after that.) | |
| 979 @end defvar | |
| 980 | |
| 981 @defvar special-display-regexps | |
| 982 A list of regular expressions that specify buffers that should be | |
| 983 displayed specially. If the buffer's name matches any of the regular | |
| 984 expressions in this list, @code{display-buffer} handles the buffer | |
| 985 specially. | |
| 986 | |
| 987 By default, special display means to give the buffer a dedicated frame. | |
| 988 | |
| 989 If an element is a list, instead of a string, then the @sc{car} of the | |
| 990 list is the regular expression, and the rest of the list says how to | |
| 991 create the frame. See above, under @code{special-display-buffer-names}. | |
| 992 @end defvar | |
| 993 | |
| 994 @defvar special-display-function | |
| 995 This variable holds the function to call to display a buffer specially. | |
| 996 It receives the buffer as an argument, and should return the window in | |
| 997 which it is displayed. | |
| 998 | |
| 999 The default value of this variable is | |
| 1000 @code{special-display-popup-frame}. | |
| 1001 @end defvar | |
| 1002 | |
| 1003 @defun special-display-popup-frame buffer | |
| 1004 This function makes @var{buffer} visible in a frame of its own. If | |
| 1005 @var{buffer} is already displayed in a window in some frame, it makes | |
| 1006 the frame visible and raises it, to use that window. Otherwise, it | |
| 1007 creates a frame that will be dedicated to @var{buffer}. | |
| 1008 | |
| 1009 This function uses an existing window displaying @var{buffer} whether or | |
| 1010 not it is in a frame of its own; but if you set up the above variables | |
| 1011 in your init file, before @var{buffer} was created, then presumably the | |
| 1012 window was previously made by this function. | |
| 1013 @end defun | |
| 1014 | |
| 1015 @defopt special-display-frame-plist | |
| 1016 This variable holds frame properties for | |
| 1017 @code{special-display-popup-frame} to use when it creates a frame. | |
| 1018 @end defopt | |
| 1019 | |
| 1020 @defvar same-window-buffer-names | |
| 1021 A list of buffer names for buffers that should be displayed in the | |
| 1022 selected window. If the buffer's name is in this list, | |
| 1023 @code{display-buffer} handles the buffer by switching to it in the | |
| 1024 selected window. | |
| 1025 @end defvar | |
| 1026 | |
| 1027 @defvar same-window-regexps | |
| 1028 A list of regular expressions that specify buffers that should be | |
| 1029 displayed in the selected window. If the buffer's name matches any of | |
| 1030 the regular expressions in this list, @code{display-buffer} handles the | |
| 1031 buffer by switching to it in the selected window. | |
| 1032 @end defvar | |
| 1033 | |
| 1034 @c Emacs 19 feature | |
| 1035 @defvar display-buffer-function | |
| 1036 This variable is the most flexible way to customize the behavior of | |
| 1037 @code{display-buffer}. If it is non-@code{nil}, it should be a function | |
| 1038 that @code{display-buffer} calls to do the work. The function should | |
| 1039 accept two arguments, the same two arguments that @code{display-buffer} | |
| 1040 received. It should choose or create a window, display the specified | |
| 1041 buffer, and then return the window. | |
| 1042 | |
| 1043 This hook takes precedence over all the other options and hooks | |
| 1044 described above. | |
| 1045 @end defvar | |
| 1046 | |
| 1047 @c Emacs 19 feature | |
| 1048 @cindex dedicated window | |
| 1049 A window can be marked as ``dedicated'' to its buffer. Then | |
| 1050 @code{display-buffer} does not try to use that window. | |
| 1051 | |
| 1052 @defun window-dedicated-p window | |
| 1053 This function returns @code{t} if @var{window} is marked as dedicated; | |
| 1054 otherwise @code{nil}. | |
| 1055 @end defun | |
| 1056 | |
| 1057 @defun set-window-dedicated-p window flag | |
| 1058 This function marks @var{window} as dedicated if @var{flag} is | |
| 1059 non-@code{nil}, and nondedicated otherwise. | |
| 1060 @end defun | |
| 1061 | |
| 1062 @node Window Point | |
| 1063 @section Windows and Point | |
| 1064 @cindex window position | |
| 1065 @cindex window point | |
| 1066 @cindex position in window | |
| 1067 @cindex point in window | |
| 2289 | 1068 @cindex cursor in window |
| 428 | 1069 |
| 1070 Each window has its own value of point, independent of the value of | |
| 1071 point in other windows displaying the same buffer. This makes it useful | |
| 1072 to have multiple windows showing one buffer. | |
| 1073 | |
| 1074 @itemize @bullet | |
| 1075 @item | |
| 1076 The window point is established when a window is first created; it is | |
| 1077 initialized from the buffer's point, or from the window point of another | |
| 1078 window opened on the buffer if such a window exists. | |
| 1079 | |
| 1080 @item | |
| 1081 Selecting a window sets the value of point in its buffer to the window's | |
| 1082 value of point. Conversely, deselecting a window sets the window's | |
| 1083 value of point from that of the buffer. Thus, when you switch between | |
| 1084 windows that display a given buffer, the point value for the selected | |
| 1085 window is in effect in the buffer, while the point values for the other | |
| 1086 windows are stored in those windows. | |
| 1087 | |
| 1088 @item | |
| 1089 As long as the selected window displays the current buffer, the window's | |
| 1090 point and the buffer's point always move together; they remain equal. | |
| 1091 | |
| 1092 @item | |
| 1093 @xref{Positions}, for more details on buffer positions. | |
| 1094 @end itemize | |
| 1095 | |
| 1096 As far as the user is concerned, point is where the cursor is, and | |
| 1097 when the user switches to another buffer, the cursor jumps to the | |
| 1098 position of point in that buffer. | |
| 1099 | |
| 444 | 1100 @defun window-point &optional window |
| 428 | 1101 This function returns the current position of point in @var{window}. |
| 442 | 1102 For a non-selected window, this is the value point would have (in that |
| 428 | 1103 window's buffer) if that window were selected. |
| 1104 | |
| 1105 When @var{window} is the selected window and its buffer is also the | |
| 444 | 1106 current buffer, the value returned is the same as the value of point in |
| 1107 that buffer. | |
| 428 | 1108 |
| 1109 Strictly speaking, it would be more correct to return the | |
| 1110 ``top-level'' value of point, outside of any @code{save-excursion} | |
| 1111 forms. But that value is hard to find. | |
| 1112 @end defun | |
| 1113 | |
| 1114 @defun set-window-point window position | |
| 1115 This function positions point in @var{window} at position | |
| 1116 @var{position} in @var{window}'s buffer. | |
| 1117 @end defun | |
| 1118 | |
| 2289 | 1119 @defun current-pixel-row &optional window pos |
| 1120 @defunx current-pixel-column &optional window pos | |
| 1121 @cindex cursor pixel row | |
| 1122 @cindex window point pixel row | |
| 1123 @cindex cursor pixel column | |
| 1124 @cindex window point pixel column | |
| 1125 The function, @code{current-pixel-row}, returns the vertical location, | |
| 1126 in pixels, of the point @var{pos} within the specified @var{window}; | |
| 1127 similarly, @code{current-pixel-column} returns the corresponding | |
| 1128 horizontal location. The position returned is that of the upper-left | |
| 1129 corner of the cursor, and is relative to the upper-left location of the | |
| 1130 window. If @var{window} is @code{nil}, the function uses the selected | |
| 1131 window. If @var{pos} is @code{nil}, the value of @code{window-point} is | |
| 1132 used. | |
| 1133 | |
| 1134 Note that the coordinates are relative to the current XEmacs window, and | |
| 1135 are not relative to the XEmacs X11 window. To obtain the coordinates | |
| 1136 relative to the X11 window, you must also take into account the spacings | |
| 1137 of any menubars, gutters, toolbars, margins, etc., as well as any window | |
| 1138 offsets. The function, @code{window-pixel-edges} (@pxref{Position of | |
| 1139 Window}), can be used to help calculate the location relative to the | |
| 1140 frame. | |
| 1141 | |
| 1142 @emph{Important note}: in order for these functions to return a correct, | |
| 1143 non-nil value, two criteria @emph{must} be satisfied: | |
| 1144 | |
| 1145 @itemize @bullet | |
| 1146 | |
| 1147 @item | |
| 1148 The location of @code{pos} must be visible within the specified window. | |
| 1149 If @var{pos} is outside the visible area, @code{nil} is returned. | |
| 1150 | |
| 1151 @item | |
| 1152 As the pixel location is determined from the redisplay tables, the | |
| 1153 redisplay tables must be up-to-date. In other words, the XEmacs | |
| 1154 window(s), as seen by the user, must be correct (to improve performance, | |
| 1155 XEmacs generally defers display updates until control returns back to | |
| 1156 the idle loop). To insure that the redisplay tables are up-to-date, one | |
| 1157 of the following must generally be done @emph{before} calling | |
| 1158 @code{current-pixel-row} or @code{current-pixel-column}: | |
| 1159 | |
| 1160 @itemize @bullet | |
| 1161 | |
| 1162 @item | |
| 1163 If the window in question is not in a new frame, you can force a | |
| 1164 redisplay using @code{(sit-for 0)}. See @code{sit-for} in | |
| 1165 @ref{Waiting}. | |
| 1166 | |
| 1167 @item | |
| 1168 If the window in question is in a new frame, you must call code like the | |
| 1169 following: | |
| 1170 | |
| 1171 @example | |
| 1172 @group | |
| 1173 (while (not (frame-visible-p frame)) | |
| 1174 (sleep-for .5)) | |
| 1175 @end group | |
| 1176 @end example | |
| 1177 | |
| 1178 @end itemize | |
| 1179 | |
| 1180 @end itemize | |
| 1181 | |
| 1182 If one of these is not done, the return value may be incorrect, even if | |
| 1183 it is non-nil. | |
| 1184 | |
| 1185 @end defun | |
| 1186 | |
| 428 | 1187 @node Window Start |
| 1188 @section The Window Start Position | |
| 1189 | |
| 1190 Each window contains a marker used to keep track of a buffer position | |
| 1191 that specifies where in the buffer display should start. This position | |
| 1192 is called the @dfn{display-start} position of the window (or just the | |
| 1193 @dfn{start}). The character after this position is the one that appears | |
| 1194 at the upper left corner of the window. It is usually, but not | |
| 1195 inevitably, at the beginning of a text line. | |
| 1196 | |
| 1197 @defun window-start &optional window | |
| 1198 @cindex window top line | |
| 1199 This function returns the display-start position of window | |
| 1200 @var{window}. If @var{window} is @code{nil}, the selected window is | |
| 444 | 1201 used. For example, |
| 428 | 1202 |
| 1203 @example | |
| 1204 @group | |
| 1205 (window-start) | |
| 1206 @result{} 7058 | |
| 1207 @end group | |
| 1208 @end example | |
| 1209 | |
| 1210 When you create a window, or display a different buffer in it, the | |
| 1211 display-start position is set to a display-start position recently used | |
| 1212 for the same buffer, or 1 if the buffer doesn't have any. | |
| 1213 | |
| 1214 For a realistic example, see the description of @code{count-lines} in | |
| 1215 @ref{Text Lines}. | |
| 1216 @end defun | |
| 1217 | |
| 444 | 1218 @defun window-end &optional window guarantee |
| 428 | 1219 This function returns the position of the end of the display in window |
| 1220 @var{window}. If @var{window} is @code{nil}, the selected window is | |
| 1221 used. | |
| 1222 | |
| 444 | 1223 Simply changing the buffer text or setting @code{window-start} does not |
| 1224 update the value that @code{window-end} returns. The value is updated | |
| 1225 only when Emacs redisplays and redisplay actually finishes. | |
| 428 | 1226 |
| 1227 If the last redisplay of @var{window} was preempted, and did not finish, | |
| 1228 Emacs does not know the position of the end of display in that window. | |
| 1229 In that case, this function returns a value that is not correct. In a | |
| 1230 future version, @code{window-end} will return @code{nil} in that case. | |
| 444 | 1231 |
| 1232 If optional arg @var{guarantee} is non-@code{nil}, the return value is | |
| 1233 guaranteed to be the same as @code{window-end} would return at the end | |
| 1234 of the next full redisplay assuming nothing else changes in the | |
| 1235 meantime. This function is potentially much slower with this flag set. | |
| 1236 | |
| 428 | 1237 @ignore |
| 1238 in that case, this function returns @code{nil}. You can compute where | |
| 1239 the end of the window @emph{would} have been, if redisplay had finished, | |
| 1240 like this: | |
| 1241 | |
| 1242 @example | |
| 1243 (save-excursion | |
| 1244 (goto-char (window-start window)) | |
| 1245 (vertical-motion (1- (window-height window)) | |
| 1246 window) | |
| 1247 (point)) | |
| 1248 @end example | |
| 1249 @end ignore | |
| 1250 @end defun | |
| 1251 | |
| 1252 @defun set-window-start window position &optional noforce | |
| 1253 This function sets the display-start position of @var{window} to | |
| 1254 @var{position} in @var{window}'s buffer. It returns @var{position}. | |
| 1255 | |
| 1256 The display routines insist that the position of point be visible when a | |
| 1257 buffer is displayed. Normally, they change the display-start position | |
| 1258 (that is, scroll the window) whenever necessary to make point visible. | |
| 1259 However, if you specify the start position with this function using | |
| 1260 @code{nil} for @var{noforce}, it means you want display to start at | |
| 1261 @var{position} even if that would put the location of point off the | |
| 1262 screen. If this does place point off screen, the display routines move | |
| 1263 point to the left margin on the middle line in the window. | |
| 1264 | |
| 1265 For example, if point @w{is 1} and you set the start of the window @w{to | |
| 1266 2}, then point would be ``above'' the top of the window. The display | |
| 1267 routines will automatically move point if it is still 1 when redisplay | |
| 1268 occurs. Here is an example: | |
| 1269 | |
| 1270 @example | |
| 1271 @group | |
| 1272 ;; @r{Here is what @samp{foo} looks like before executing} | |
| 1273 ;; @r{the @code{set-window-start} expression.} | |
| 1274 @end group | |
| 1275 | |
| 1276 @group | |
| 1277 ---------- Buffer: foo ---------- | |
| 1278 @point{}This is the contents of buffer foo. | |
| 1279 2 | |
| 1280 3 | |
| 1281 4 | |
| 1282 5 | |
| 1283 6 | |
| 1284 ---------- Buffer: foo ---------- | |
| 1285 @end group | |
| 1286 | |
| 1287 @group | |
| 1288 (set-window-start | |
| 1289 (selected-window) | |
| 1290 (1+ (window-start))) | |
| 1291 @result{} 2 | |
| 1292 @end group | |
| 1293 | |
| 1294 @group | |
| 1295 ;; @r{Here is what @samp{foo} looks like after executing} | |
| 1296 ;; @r{the @code{set-window-start} expression.} | |
| 1297 ---------- Buffer: foo ---------- | |
| 1298 his is the contents of buffer foo. | |
| 1299 2 | |
| 1300 3 | |
| 1301 @point{}4 | |
| 1302 5 | |
| 1303 6 | |
| 1304 ---------- Buffer: foo ---------- | |
| 1305 @end group | |
| 1306 @end example | |
| 1307 | |
| 1308 If @var{noforce} is non-@code{nil}, and @var{position} would place point | |
| 1309 off screen at the next redisplay, then redisplay computes a new window-start | |
| 1310 position that works well with point, and thus @var{position} is not used. | |
| 1311 @end defun | |
| 1312 | |
| 1313 @defun pos-visible-in-window-p &optional position window | |
| 1314 This function returns @code{t} if @var{position} is within the range | |
| 1315 of text currently visible on the screen in @var{window}. It returns | |
| 1316 @code{nil} if @var{position} is scrolled vertically out of view. The | |
| 1317 argument @var{position} defaults to the current position of point; | |
| 1318 @var{window}, to the selected window. Here is an example: | |
| 1319 | |
| 1320 @example | |
| 1321 @group | |
| 1322 (or (pos-visible-in-window-p | |
| 1323 (point) (selected-window)) | |
| 1324 (recenter 0)) | |
| 1325 @end group | |
| 1326 @end example | |
| 1327 | |
| 1328 The @code{pos-visible-in-window-p} function considers only vertical | |
| 1329 scrolling. If @var{position} is out of view only because @var{window} | |
| 1330 has been scrolled horizontally, @code{pos-visible-in-window-p} returns | |
| 1331 @code{t}. @xref{Horizontal Scrolling}. | |
| 1332 @end defun | |
| 1333 | |
| 1334 @node Vertical Scrolling | |
| 1335 @section Vertical Scrolling | |
| 1336 @cindex vertical scrolling | |
| 1337 @cindex scrolling vertically | |
| 1338 | |
| 1339 Vertical scrolling means moving the text up or down in a window. It | |
| 1340 works by changing the value of the window's display-start location. It | |
| 1341 may also change the value of @code{window-point} to keep it on the | |
| 1342 screen. | |
| 1343 | |
| 1344 In the commands @code{scroll-up} and @code{scroll-down}, the directions | |
| 1345 ``up'' and ``down'' refer to the motion of the text in the buffer at which | |
| 1346 you are looking through the window. Imagine that the text is | |
| 1347 written on a long roll of paper and that the scrolling commands move the | |
| 1348 paper up and down. Thus, if you are looking at text in the middle of a | |
| 1349 buffer and repeatedly call @code{scroll-down}, you will eventually see | |
| 1350 the beginning of the buffer. | |
| 1351 | |
| 1352 Some people have urged that the opposite convention be used: they | |
| 1353 imagine that the window moves over text that remains in place. Then | |
| 1354 ``down'' commands would take you to the end of the buffer. This view is | |
| 1355 more consistent with the actual relationship between windows and the | |
| 1356 text in the buffer, but it is less like what the user sees. The | |
| 1357 position of a window on the terminal does not move, and short scrolling | |
| 1358 commands clearly move the text up or down on the screen. We have chosen | |
| 1359 names that fit the user's point of view. | |
| 1360 | |
| 1361 The scrolling functions (aside from @code{scroll-other-window}) have | |
| 1362 unpredictable results if the current buffer is different from the buffer | |
| 1363 that is displayed in the selected window. @xref{Current Buffer}. | |
| 1364 | |
| 444 | 1365 @deffn Command scroll-up &optional lines |
| 428 | 1366 This function scrolls the text in the selected window upward |
| 444 | 1367 @var{lines} lines. If @var{lines} is negative, scrolling is actually |
| 428 | 1368 downward. |
| 1369 | |
| 444 | 1370 If @var{lines} is @code{nil} (or omitted), then the length of scroll |
| 428 | 1371 is @code{next-screen-context-lines} lines less than the usable height of |
| 1372 the window (not counting its modeline). | |
| 1373 | |
| 1374 @code{scroll-up} returns @code{nil}. | |
| 1375 @end deffn | |
| 1376 | |
| 444 | 1377 @deffn Command scroll-down &optional lines |
| 428 | 1378 This function scrolls the text in the selected window downward |
| 444 | 1379 @var{lines} lines. If @var{lines} is negative, scrolling is actually |
| 428 | 1380 upward. |
| 1381 | |
| 444 | 1382 If @var{lines} is omitted or @code{nil}, then the length of the scroll |
| 428 | 1383 is @code{next-screen-context-lines} lines less than the usable height of |
| 1384 the window (not counting its mode line). | |
| 1385 | |
| 1386 @code{scroll-down} returns @code{nil}. | |
| 1387 @end deffn | |
| 1388 | |
| 444 | 1389 @deffn Command scroll-other-window &optional lines |
| 1390 This function scrolls the text in another window upward @var{lines} | |
| 1391 lines. Negative values of @var{lines}, or @code{nil}, are handled | |
| 428 | 1392 as in @code{scroll-up}. |
| 1393 | |
| 1394 You can specify a buffer to scroll with the variable | |
| 1395 @code{other-window-scroll-buffer}. When the selected window is the | |
| 1396 minibuffer, the next window is normally the one at the top left corner. | |
| 1397 You can specify a different window to scroll with the variable | |
| 1398 @code{minibuffer-scroll-window}. This variable has no effect when any | |
| 1399 other window is selected. @xref{Minibuffer Misc}. | |
| 1400 | |
| 1401 When the minibuffer is active, it is the next window if the selected | |
| 1402 window is the one at the bottom right corner. In this case, | |
| 1403 @code{scroll-other-window} attempts to scroll the minibuffer. If the | |
| 1404 minibuffer contains just one line, it has nowhere to scroll to, so the | |
| 1405 line reappears after the echo area momentarily displays the message | |
| 1406 ``Beginning of buffer''. | |
| 1407 @end deffn | |
| 1408 | |
| 1409 @c Emacs 19 feature | |
| 1410 @defvar other-window-scroll-buffer | |
| 1411 If this variable is non-@code{nil}, it tells @code{scroll-other-window} | |
| 1412 which buffer to scroll. | |
| 1413 @end defvar | |
| 1414 | |
| 1415 @defopt scroll-step | |
| 1416 This variable controls how scrolling is done automatically when point | |
| 1417 moves off the screen. If the value is zero, then redisplay scrolls the | |
| 1418 text to center point vertically in the window. If the value is a | |
| 1419 positive integer @var{n}, then redisplay brings point back on screen by | |
| 1420 scrolling @var{n} lines in either direction, if possible; otherwise, it | |
| 1421 centers point. The default value is zero. | |
| 1422 @end defopt | |
| 1423 | |
| 1424 @defopt scroll-conservatively | |
| 1425 This variable controls how many lines Emacs tries to scroll before | |
| 1426 recentering. If you set it to a small number, then when you move point | |
| 1427 a short distance off the screen, XEmacs will scroll the screen just far | |
| 1428 enough to bring point back on screen, provided that does not exceed | |
| 1429 @code{scroll-conservatively} lines. This variable overrides the | |
| 1430 redisplay preemption. | |
| 1431 @end defopt | |
| 1432 | |
| 1433 @defopt next-screen-context-lines | |
| 1434 The value of this variable is the number of lines of continuity to | |
| 1435 retain when scrolling by full screens. For example, @code{scroll-up} | |
| 1436 with an argument of @code{nil} scrolls so that this many lines at the | |
| 1437 bottom of the window appear instead at the top. The default value is | |
| 1438 @code{2}. | |
| 1439 @end defopt | |
| 1440 | |
| 444 | 1441 @deffn Command recenter &optional location window |
| 428 | 1442 @cindex centering point |
| 444 | 1443 This function scrolls @var{window} (which defaults to the selected |
| 1444 window) to put the text where point is located at a specified vertical | |
| 1445 position within the window. | |
| 428 | 1446 |
| 444 | 1447 If @var{location} is a nonnegative number, it puts the line containing |
| 1448 point @var{location} lines down from the top of the window. If @var{location} | |
| 428 | 1449 is a negative number, then it counts upward from the bottom of the |
| 1450 window, so that @minus{}1 stands for the last usable line in the window. | |
| 444 | 1451 If @var{location} is a non-@code{nil} list, then it stands for the line in |
| 428 | 1452 the middle of the window. |
| 1453 | |
| 444 | 1454 If @var{location} is @code{nil}, @code{recenter} puts the line containing |
| 428 | 1455 point in the middle of the window, then clears and redisplays the entire |
| 1456 selected frame. | |
| 1457 | |
| 444 | 1458 When @code{recenter} is called interactively, @var{location} is the raw |
| 428 | 1459 prefix argument. Thus, typing @kbd{C-u} as the prefix sets the |
| 444 | 1460 @var{location} to a non-@code{nil} list, while typing @kbd{C-u 4} sets |
| 1461 @var{location} to 4, which positions the current line four lines from the | |
| 428 | 1462 top. |
| 1463 | |
| 1464 With an argument of zero, @code{recenter} positions the current line at | |
| 1465 the top of the window. This action is so handy that some people make a | |
| 1466 separate key binding to do this. For example, | |
| 1467 | |
| 1468 @example | |
| 1469 @group | |
| 1470 (defun line-to-top-of-window () | |
| 1471 "Scroll current line to top of window. | |
| 1472 Replaces three keystroke sequence C-u 0 C-l." | |
| 444 | 1473 (interactive) |
| 428 | 1474 (recenter 0)) |
| 1475 | |
| 444 | 1476 (global-set-key [kp-multiply] 'line-to-top-of-window) |
| 428 | 1477 @end group |
| 1478 @end example | |
| 1479 @end deffn | |
| 1480 | |
| 1481 @node Horizontal Scrolling | |
| 1482 @section Horizontal Scrolling | |
| 1483 @cindex horizontal scrolling | |
| 1484 | |
| 1485 Because we read English first from top to bottom and second from left | |
| 1486 to right, horizontal scrolling is not like vertical scrolling. Vertical | |
| 1487 scrolling involves selection of a contiguous portion of text to display. | |
| 1488 Horizontal scrolling causes part of each line to go off screen. The | |
| 1489 amount of horizontal scrolling is therefore specified as a number of | |
| 1490 columns rather than as a position in the buffer. It has nothing to do | |
| 1491 with the display-start position returned by @code{window-start}. | |
| 1492 | |
| 1493 Usually, no horizontal scrolling is in effect; then the leftmost | |
| 1494 column is at the left edge of the window. In this state, scrolling to | |
| 1495 the right is meaningless, since there is no data to the left of the | |
| 1496 screen to be revealed by it; so this is not allowed. Scrolling to the | |
| 1497 left is allowed; it scrolls the first columns of text off the edge of | |
| 1498 the window and can reveal additional columns on the right that were | |
| 1499 truncated before. Once a window has a nonzero amount of leftward | |
| 1500 horizontal scrolling, you can scroll it back to the right, but only so | |
| 1501 far as to reduce the net horizontal scroll to zero. There is no limit | |
| 1502 to how far left you can scroll, but eventually all the text will | |
| 1503 disappear off the left edge. | |
| 1504 | |
| 444 | 1505 @deffn Command scroll-left &optional count |
| 428 | 1506 This function scrolls the selected window @var{count} columns to the |
| 1507 left (or to the right if @var{count} is negative). The return value is | |
| 1508 the total amount of leftward horizontal scrolling in effect after the | |
| 1509 change---just like the value returned by @code{window-hscroll} (below). | |
| 1510 @end deffn | |
| 1511 | |
| 444 | 1512 @deffn Command scroll-right &optional count |
| 428 | 1513 This function scrolls the selected window @var{count} columns to the |
| 1514 right (or to the left if @var{count} is negative). The return value is | |
| 1515 the total amount of leftward horizontal scrolling in effect after the | |
| 1516 change---just like the value returned by @code{window-hscroll} (below). | |
| 1517 | |
| 1518 Once you scroll a window as far right as it can go, back to its normal | |
| 1519 position where the total leftward scrolling is zero, attempts to scroll | |
| 1520 any farther right have no effect. | |
| 1521 @end deffn | |
| 1522 | |
| 1523 @defun window-hscroll &optional window | |
| 1524 This function returns the total leftward horizontal scrolling of | |
| 1525 @var{window}---the number of columns by which the text in @var{window} | |
| 1526 is scrolled left past the left margin. | |
| 1527 | |
| 1528 The value is never negative. It is zero when no horizontal scrolling | |
| 1529 has been done in @var{window} (which is usually the case). | |
| 1530 | |
| 1531 If @var{window} is @code{nil}, the selected window is used. | |
| 1532 | |
| 1533 @example | |
| 1534 @group | |
| 1535 (window-hscroll) | |
| 1536 @result{} 0 | |
| 1537 @end group | |
| 1538 @group | |
| 1539 (scroll-left 5) | |
| 1540 @result{} 5 | |
| 1541 @end group | |
| 1542 @group | |
| 1543 (window-hscroll) | |
| 1544 @result{} 5 | |
| 1545 @end group | |
| 1546 @end example | |
| 1547 @end defun | |
| 1548 | |
| 1549 @defun set-window-hscroll window columns | |
| 1550 This function sets the number of columns from the left margin that | |
| 1551 @var{window} is scrolled to the value of @var{columns}. The argument | |
| 1552 @var{columns} should be zero or positive; if not, it is taken as zero. | |
| 1553 | |
| 1554 The value returned is @var{columns}. | |
| 1555 | |
| 1556 @example | |
| 1557 @group | |
| 1558 (set-window-hscroll (selected-window) 10) | |
| 1559 @result{} 10 | |
| 1560 @end group | |
| 1561 @end example | |
| 1562 @end defun | |
| 1563 | |
| 1564 Here is how you can determine whether a given position @var{position} | |
| 1565 is off the screen due to horizontal scrolling: | |
| 1566 | |
| 1567 @example | |
| 1568 @group | |
| 1569 (defun hscroll-on-screen (window position) | |
| 444 | 1570 (save-excursion |
| 428 | 1571 (goto-char position) |
| 444 | 1572 (and |
| 428 | 1573 (>= (- (current-column) (window-hscroll window)) 0) |
| 1574 (< (- (current-column) (window-hscroll window)) | |
| 1575 (window-width window))))) | |
| 1576 @end group | |
| 1577 @end example | |
| 1578 @node Size of Window | |
| 1579 @section The Size of a Window | |
| 1580 @cindex window size | |
| 1581 @cindex size of window | |
| 1582 | |
| 1583 An Emacs window is rectangular, and its size information consists of | |
| 1584 the height (in lines or pixels) and the width (in character positions | |
| 1585 or pixels). The modeline is included in the height. The pixel | |
| 1586 width and height values include scrollbars and margins, while the | |
| 1587 line/character-position values do not. | |
| 1588 | |
| 1589 Note that the height in lines, and the width in characters, are | |
| 1590 determined by dividing the corresponding pixel value by the height or | |
| 1591 width of the default font in that window (if this is a variable-width | |
| 1592 font, the average width is used). The resulting values may or may not | |
| 1593 represent the actual number of lines in the window, or the actual number | |
| 1594 of character positions in any particular line, esp. if there are pixmaps | |
| 1595 or various different fonts in the window. | |
| 1596 | |
| 1597 The following functions return size information about a window: | |
| 1598 | |
| 1599 @defun window-height &optional window | |
| 1600 This function returns the number of lines in @var{window}, including | |
| 1601 its modeline but not including the horizontal scrollbar, if any (this | |
| 1602 is different from @code{window-pixel-height}). If @var{window} is | |
| 1603 @code{nil}, the function uses the selected window. | |
| 1604 | |
| 1605 @example | |
| 1606 @group | |
| 1607 (window-height) | |
| 1608 @result{} 40 | |
| 1609 @end group | |
| 1610 @group | |
| 1611 (split-window-vertically) | |
| 1612 @result{} #<window on "windows.texi" 0x679b> | |
| 1613 @end group | |
| 1614 @group | |
| 1615 (window-height) | |
| 1616 @result{} 20 | |
| 1617 @end group | |
| 1618 @end example | |
| 1619 @end defun | |
| 1620 | |
| 1621 @defun window-width &optional window | |
| 1622 This function returns the number of columns in @var{window}, not | |
| 1623 including any left margin, right margin, or vertical scrollbar (this is | |
| 1624 different from @code{window-pixel-width}). If @var{window} is | |
| 1625 @code{nil}, the function uses the selected window. | |
| 1626 | |
| 1627 @example | |
| 1628 @group | |
| 1629 (window-width) | |
| 1630 @result{} 80 | |
| 1631 @end group | |
| 1632 @group | |
| 1633 (window-height) | |
| 1634 @result{} 40 | |
| 1635 @end group | |
| 1636 @group | |
| 1637 (split-window-horizontally) | |
| 1638 @result{} #<window on "windows.texi" 0x7538> | |
| 1639 @end group | |
| 1640 @group | |
| 1641 (window-width) | |
| 1642 @result{} 39 | |
| 1643 @end group | |
| 1644 @end example | |
| 1645 @end defun | |
| 1646 | |
| 1647 Note that after splitting the window into two side-by-side windows, | |
| 1648 the width of each window is less the half the width of the original | |
| 1649 window because a vertical scrollbar appeared between the windows, | |
| 1650 occupying two columns worth of space. Also, the height shrunk by | |
| 1651 one because horizontal scrollbars appeared that weren't there | |
| 1652 before. (Horizontal scrollbars appear only when lines are | |
| 1653 truncated, not when they wrap. This is usually the case for | |
| 1654 horizontally split windows but not for full-frame windows. You | |
| 1655 can change this using the variables @code{truncate-lines} and | |
| 1656 @code{truncate-partial-width-windows}.) | |
| 1657 | |
| 1658 @defun window-pixel-height &optional window | |
| 1659 This function returns the height of @var{window} in pixels, including | |
| 1660 its modeline and horizontal scrollbar, if any. If @var{window} is | |
| 1661 @code{nil}, the function uses the selected window. | |
| 1662 | |
| 1663 @example | |
| 1664 @group | |
| 1665 (window-pixel-height) | |
| 1666 @result{} 600 | |
| 1667 @end group | |
| 1668 @group | |
| 1669 (split-window-vertically) | |
| 1670 @result{} #<window on "windows.texi" 0x68a6> | |
| 1671 @end group | |
| 1672 @group | |
| 1673 (window-pixel-height) | |
| 1674 @result{} 300 | |
| 1675 @end group | |
| 1676 @end example | |
| 1677 @end defun | |
| 1678 | |
| 1679 @defun window-pixel-width &optional window | |
| 1680 This function returns the width of @var{window} in pixels, including | |
| 1681 any left margin, right margin, or vertical scrollbar that may be | |
| 1682 displayed alongside it. If @var{window} is @code{nil}, the function | |
| 1683 uses the selected window. | |
| 1684 | |
| 1685 @example | |
| 1686 @group | |
| 1687 (window-pixel-width) | |
| 1688 @result{} 735 | |
| 1689 @end group | |
| 1690 @group | |
| 1691 (window-pixel-height) | |
| 1692 @result{} 600 | |
| 1693 @end group | |
| 1694 @group | |
| 1695 (split-window-horizontally) | |
| 1696 @result{} #<window on "windows.texi" 0x7538> | |
| 1697 @end group | |
| 1698 @group | |
| 1699 (window-pixel-width) | |
| 1700 @result{} 367 | |
| 1701 @end group | |
| 1702 @group | |
| 1703 (window-pixel-height) | |
| 1704 @result{} 600 | |
| 1705 @end group | |
| 1706 @end example | |
| 1707 @end defun | |
| 1708 | |
| 1709 @defun window-text-area-pixel-height &optional window | |
| 1710 This function returns the height in pixels of the text displaying | |
| 1711 portion of @var{window}, which defaults to the selected window. Unlike | |
| 1712 @code{window-pixel-height}, the space occupied by the modeline and | |
| 1713 horizontal scrollbar, if any, is not counted. | |
| 1714 @end defun | |
| 1715 | |
| 1716 @defun window-text-area-pixel-width &optional window | |
| 1717 This function returns the width in pixels of the text displaying | |
| 1718 portion of @var{window}, which defaults to the selected window. Unlike | |
| 1719 @code{window-pixel-width}, the space occupied by the vertical scrollbar | |
| 1720 and divider, if any, is not counted. | |
| 1721 @end defun | |
| 1722 | |
| 1723 @defun window-displayed-text-pixel-height &optional window noclipped | |
| 1724 This function returns the height in pixels of the text displayed in | |
| 1725 @var{window}, which defaults to the selected window. Unlike | |
| 1726 @code{window-text-area-pixel-height}, any blank space below the | |
| 444 | 1727 end of the buffer is not included. If optional argument @var{noclipped} |
| 428 | 1728 is non-@code{nil}, any space occupied by clipped lines will not be |
| 1729 included. | |
| 1730 @end defun | |
| 1731 | |
| 1732 @node Position of Window | |
| 1733 @section The Position of a Window | |
| 1734 @cindex window position | |
| 1735 @cindex position of window | |
| 1736 | |
| 1737 XEmacs provides functions to determine the absolute location of windows | |
| 1738 within a frame, and the relative location of a window in comparison to | |
| 1739 other windows in the same frame. | |
| 1740 | |
| 1741 @defun window-pixel-edges &optional window | |
| 1742 This function returns a list of the pixel edge coordinates of | |
| 1743 @var{window}. If @var{window} is @code{nil}, the selected window is | |
| 1744 used. | |
| 1745 | |
| 1746 The order of the list is @code{(@var{left} @var{top} @var{right} | |
| 1747 @var{bottom})}, all elements relative to 0, 0 at the top left corner of | |
| 444 | 1748 @var{window}'s frame. The element @var{right} of the value is one more |
| 1749 than the rightmost pixel used by @var{window} (including any left | |
| 1750 margin, right margin, or vertical scrollbar displayed alongside it), and | |
| 428 | 1751 @var{bottom} is one more than the bottommost pixel used by @var{window} |
| 444 | 1752 (including any modeline or horizontal scrollbar displayed above or below |
| 1753 it). The frame area does not include any frame menubars, toolbars, or | |
| 1754 gutters that may be displayed; thus, for example, if there is only one | |
| 1755 window on the frame, the values for @var{left} and @var{top} will always | |
| 1756 be 0. | |
| 428 | 1757 |
| 1758 If @var{window} is at the upper left corner of its frame, @var{right} | |
| 1759 and @var{bottom} are the same as the values returned by | |
| 1760 @code{(window-pixel-width)} and @code{(window-pixel-height)} | |
| 444 | 1761 respectively, and @var{left} and @var{top} are zero. |
| 428 | 1762 @end defun |
| 1763 | |
| 1764 There is no longer a function @code{window-edges} because it does not | |
| 1765 make sense in a world with variable-width and variable-height lines, | |
| 1766 as are allowed in XEmacs. | |
| 1767 | |
| 1768 @defun window-highest-p window | |
| 1769 This function returns non-@code{nil} if @var{window} is along the | |
| 1770 top of its frame. | |
| 1771 @end defun | |
| 1772 | |
| 1773 @defun window-lowest-p window | |
| 1774 This function returns non-@code{nil} if @var{window} is along the | |
| 1775 bottom of its frame. | |
| 1776 @end defun | |
| 1777 | |
| 1778 @defun window-text-area-pixel-edges &optional window | |
| 1779 This function allows one to determine the location of the | |
| 1780 text-displaying portion of @var{window}, which defaults to the selected | |
| 1781 window, with respect to the top left corner of the window. It returns | |
| 1782 a list of integer pixel positions @code{(left top right bottom)}, all | |
| 1783 relative to @code{(0,0)} at the top left corner of the window. | |
| 1784 @end defun | |
| 1785 | |
| 1786 @node Resizing Windows | |
| 1787 @section Changing the Size of a Window | |
| 1788 @cindex window resizing | |
| 1789 @cindex changing window size | |
| 1790 @cindex window size, changing | |
| 1791 | |
| 1792 The window size functions fall into two classes: high-level commands | |
| 1793 that change the size of windows and low-level functions that access | |
| 1794 window size. XEmacs does not permit overlapping windows or gaps between | |
| 1795 windows, so resizing one window affects other windows. | |
| 1796 | |
| 444 | 1797 @deffn Command enlarge-window count &optional horizontal window |
| 1798 This function makes the selected window @var{count} lines taller, | |
| 428 | 1799 stealing lines from neighboring windows. It takes the lines from one |
| 1800 window at a time until that window is used up, then takes from another. | |
| 1801 If a window from which lines are stolen shrinks below | |
| 1802 @code{window-min-height} lines, that window disappears. | |
| 1803 | |
| 1804 If @var{horizontal} is non-@code{nil}, this function makes | |
| 444 | 1805 @var{window} wider by @var{count} columns, stealing columns instead of |
| 428 | 1806 lines. If a window from which columns are stolen shrinks below |
| 1807 @code{window-min-width} columns, that window disappears. | |
| 1808 | |
| 1809 If the requested size would exceed that of the window's frame, then the | |
| 1810 function makes the window occupy the entire height (or width) of the | |
| 1811 frame. | |
| 1812 | |
| 444 | 1813 If @var{count} is negative, this function shrinks the window by |
| 1814 @minus{}@var{count} lines or columns. If that makes the window smaller | |
| 428 | 1815 than the minimum size (@code{window-min-height} and |
| 1816 @code{window-min-width}), @code{enlarge-window} deletes the window. | |
| 1817 | |
| 1818 If @var{window} is non-@code{nil}, it specifies a window to change | |
| 1819 instead of the selected window. | |
| 1820 | |
| 444 | 1821 @code{enlarge-window} returns @code{nil}. |
| 428 | 1822 @end deffn |
| 1823 | |
| 1824 @deffn Command enlarge-window-horizontally columns | |
| 1825 This function makes the selected window @var{columns} wider. | |
| 1826 It could be defined as follows: | |
| 1827 | |
| 1828 @example | |
| 1829 @group | |
| 1830 (defun enlarge-window-horizontally (columns) | |
| 1831 (enlarge-window columns t)) | |
| 1832 @end group | |
| 1833 @end example | |
| 1834 @end deffn | |
| 1835 | |
| 1836 @deffn Command enlarge-window-pixels count &optional side window | |
| 444 | 1837 This function makes the selected window @var{count} pixels larger. |
| 1838 When called from Lisp, optional second argument @var{side} | |
| 1839 non-@code{nil} means to grow sideways @var{count} pixels, and optional | |
| 1840 third argument @var{window} specifies the window to change instead of | |
| 1841 the selected window. | |
| 428 | 1842 @end deffn |
| 1843 | |
| 444 | 1844 @deffn Command shrink-window count &optional horizontal window |
| 428 | 1845 This function is like @code{enlarge-window} but negates the argument |
| 444 | 1846 @var{count}, making the selected window smaller by giving lines (or |
| 428 | 1847 columns) to the other windows. If the window shrinks below |
| 1848 @code{window-min-height} or @code{window-min-width}, then it disappears. | |
| 1849 | |
| 444 | 1850 If @var{count} is negative, the window is enlarged by @minus{}@var{count} |
| 428 | 1851 lines or columns. |
| 1852 | |
| 1853 If @var{window} is non-@code{nil}, it specifies a window to change | |
| 1854 instead of the selected window. | |
| 1855 @end deffn | |
| 1856 | |
| 1857 @deffn Command shrink-window-horizontally columns | |
| 1858 This function makes the selected window @var{columns} narrower. | |
| 1859 It could be defined as follows: | |
| 1860 | |
| 1861 @example | |
| 1862 @group | |
| 1863 (defun shrink-window-horizontally (columns) | |
| 1864 (shrink-window columns t)) | |
| 1865 @end group | |
| 1866 @end example | |
| 1867 @end deffn | |
| 1868 | |
| 1869 @deffn Command shrink-window-pixels count &optional side window | |
| 1870 This function makes the selected window @var{count} pixels smaller. | |
| 1871 When called from Lisp, optional second argument @var{side} | |
| 1872 non-@code{nil} means to shrink sideways @var{count} pixels, and optional | |
| 1873 third argument @var{window} specifies the window to change instead of | |
| 1874 the selected window. | |
| 1875 @end deffn | |
| 1876 | |
| 1877 @cindex minimum window size | |
| 1878 The following two variables constrain the window-size-changing | |
| 1879 functions to a minimum height and width. | |
| 1880 | |
| 1881 @defopt window-min-height | |
| 1882 The value of this variable determines how short a window may become | |
| 1883 before it is automatically deleted. Making a window smaller than | |
| 1884 @code{window-min-height} automatically deletes it, and no window may be | |
| 1885 created shorter than this. The absolute minimum height is two (allowing | |
| 1886 one line for the mode line, and one line for the buffer display). | |
| 1887 Actions that change window sizes reset this variable to two if it is | |
| 1888 less than two. The default value is 4. | |
| 1889 @end defopt | |
| 1890 | |
| 1891 @defopt window-min-width | |
| 1892 The value of this variable determines how narrow a window may become | |
| 1893 before it automatically deleted. Making a window smaller than | |
| 1894 @code{window-min-width} automatically deletes it, and no window may be | |
| 1895 created narrower than this. The absolute minimum width is one; any | |
| 1896 value below that is ignored. The default value is 10. | |
| 1897 @end defopt | |
| 1898 | |
| 1899 @c This is not yet implemented. Why is it "documented"? | |
| 1900 @defvar window-size-change-functions | |
| 1901 This variable holds a list of functions to be called if the size of any | |
| 1902 window changes for any reason. The functions are called just once per | |
| 1903 redisplay, and just once for each frame on which size changes have | |
| 1904 occurred. | |
| 1905 | |
| 1906 Each function receives the frame as its sole argument. There is no | |
| 1907 direct way to find out which windows changed size, or precisely how; | |
| 1908 however, if your size-change function keeps track, after each change, of | |
| 1909 the windows that interest you, you can figure out what has changed by | |
| 1910 comparing the old size data with the new. | |
| 1911 | |
| 1912 Creating or deleting windows counts as a size change, and therefore | |
| 1913 causes these functions to be called. Changing the frame size also | |
| 1914 counts, because it changes the sizes of the existing windows. | |
| 1915 | |
| 1916 It is not a good idea to use @code{save-window-excursion} in these | |
| 1917 functions, because that always counts as a size change, and it would | |
| 1918 cause these functions to be called over and over. In most cases, | |
| 1919 @code{save-selected-window} is what you need here. | |
| 1920 @end defvar | |
| 1921 | |
| 1922 @node Window Configurations | |
| 1923 @section Window Configurations | |
| 1924 @cindex window configurations | |
| 1925 @cindex saving window information | |
| 1926 | |
| 1927 A @dfn{window configuration} records the entire layout of a | |
| 1928 frame---all windows, their sizes, which buffers they contain, what part | |
| 1929 of each buffer is displayed, and the values of point and the mark. You | |
| 1930 can bring back an entire previous layout by restoring a window | |
| 1931 configuration previously saved. | |
| 1932 | |
| 1933 If you want to record all frames instead of just one, use a frame | |
| 1934 configuration instead of a window configuration. @xref{Frame | |
| 1935 Configurations}. | |
| 1936 | |
| 444 | 1937 @defun current-window-configuration &optional frame |
| 625 | 1938 This function returns a new object representing the current window |
| 1939 configuration of @var{frame}, namely the number of windows, their sizes | |
| 1940 and current buffers, which window is the selected window, and for each | |
| 1941 window the displayed buffer, the display-start position, and the | |
| 444 | 1942 positions of point and the mark. An exception is made for point in the |
| 1943 current buffer, whose value is not saved. | |
| 1944 | |
| 1945 @var{frame} defaults to the selected frame. | |
| 428 | 1946 @end defun |
| 1947 | |
| 1948 @defun set-window-configuration configuration | |
| 1949 This function restores the configuration of XEmacs's windows and | |
| 1950 buffers to the state specified by @var{configuration}. The argument | |
| 1951 @var{configuration} must be a value that was previously returned by | |
| 1952 @code{current-window-configuration}. | |
| 1953 | |
| 1954 This function always counts as a window size change and triggers | |
| 1955 execution of the @code{window-size-change-functions}. (It doesn't know | |
| 1956 how to tell whether the new configuration actually differs from the old | |
| 1957 one.) | |
| 1958 | |
| 1959 Here is a way of using this function to get the same effect | |
| 1960 as @code{save-window-excursion}: | |
| 1961 | |
| 1962 @example | |
| 1963 @group | |
| 1964 (let ((config (current-window-configuration))) | |
| 1965 (unwind-protect | |
| 1966 (progn (split-window-vertically nil) | |
| 1967 @dots{}) | |
| 1968 (set-window-configuration config))) | |
| 1969 @end group | |
| 1970 @end example | |
| 1971 @end defun | |
| 1972 | |
| 1973 @defspec save-window-excursion forms@dots{} | |
|
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|
1974 This macro records the window configuration, executes @var{forms} |
| 428 | 1975 in sequence, then restores the earlier window configuration. The window |
| 1976 configuration includes the value of point and the portion of the buffer | |
| 1977 that is visible. It also includes the choice of selected window. | |
| 1978 However, it does not include the value of point in the current buffer; | |
| 1979 use @code{save-excursion} if you wish to preserve that. | |
| 1980 | |
| 1981 Don't use this construct when @code{save-selected-window} is all you need. | |
| 1982 | |
| 1983 Exit from @code{save-window-excursion} always triggers execution of the | |
| 1984 @code{window-size-change-functions}. (It doesn't know how to tell | |
| 1985 whether the restored configuration actually differs from the one in | |
| 1986 effect at the end of the @var{forms}.) | |
| 1987 | |
| 1988 The return value is the value of the final form in @var{forms}. | |
| 1989 For example: | |
| 1990 | |
| 1991 @example | |
| 1992 @group | |
| 1993 (split-window) | |
| 1994 @result{} #<window 25 on control.texi> | |
| 1995 @end group | |
| 1996 @group | |
| 1997 (setq w (selected-window)) | |
| 1998 @result{} #<window 19 on control.texi> | |
| 1999 @end group | |
| 2000 @group | |
| 2001 (save-window-excursion | |
| 2002 (delete-other-windows w) | |
| 2003 (switch-to-buffer "foo") | |
| 2004 'do-something) | |
| 2005 @result{} do-something | |
| 2006 ;; @r{The frame is now split again.} | |
| 2007 @end group | |
| 2008 @end example | |
| 2009 @end defspec | |
| 2010 | |
| 2011 @defun window-configuration-p object | |
| 2012 This function returns @code{t} if @var{object} is a window configuration. | |
| 2013 @end defun | |
| 2014 | |
| 2015 Primitives to look inside of window configurations would make sense, | |
| 2016 but none are implemented. It is not clear they are useful enough to be | |
| 2017 worth implementing. |