Mercurial > hg > xemacs-beta
annotate man/lispref/windows.texi @ 5353:38e24b8be4ea
Improve the lexical scoping in #'block, #'return-from.
lisp/ChangeLog addition:
2011-02-07 Aidan Kehoe <kehoea@parhasard.net>
* bytecomp.el:
* bytecomp.el (byte-compile-initial-macro-environment):
Shadow `block', `return-from' here, we implement them differently
when byte-compiling.
* bytecomp.el (byte-compile-active-blocks): New.
* bytecomp.el (byte-compile-block-1): New.
* bytecomp.el (byte-compile-return-from-1): New.
* bytecomp.el (return-from-1): New.
* bytecomp.el (block-1): New.
These are two aliases that exist to have their own associated
byte-compile functions, which functions implement `block' and
`return-from'.
* cl-extra.el (cl-macroexpand-all):
Fix a bug here when macros in the environment have been compiled.
* cl-macs.el (block):
* cl-macs.el (return):
* cl-macs.el (return-from):
Be more careful about lexical scope in these macros.
* cl.el:
* cl.el ('cl-block-wrapper): Removed.
* cl.el ('cl-block-throw): Removed.
These aren't needed in code generated by this XEmacs. They
shouldn't be needed in code generated by XEmacs 21.4, but if it
turns out the packages do need them, we can put them back.
2011-01-30 Mike Sperber <mike@xemacs.org>
* font-lock.el (font-lock-fontify-pending-extents): Don't fail if
`font-lock-mode' is unset, which can happen in the middle of
`revert-buffer'.
2011-01-23 Aidan Kehoe <kehoea@parhasard.net>
* cl-macs.el (delete):
* cl-macs.el (delq):
* cl-macs.el (remove):
* cl-macs.el (remq):
Don't use the compiler macro if these functions were given the
wrong number of arguments, as happens in lisp-tests.el.
* cl-seq.el (remove, remq): Removed.
I added these to subr.el, and forgot to remove them from here.
2011-01-22 Aidan Kehoe <kehoea@parhasard.net>
* bytecomp.el (byte-compile-setq, byte-compile-set):
Remove kludge allowing keywords' values to be set, all the code
that does that is gone.
* cl-compat.el (elt-satisfies-test-p):
* faces.el (set-face-parent):
* faces.el (face-doc-string):
* gtk-font-menu.el:
* gtk-font-menu.el (gtk-reset-device-font-menus):
* msw-font-menu.el:
* msw-font-menu.el (mswindows-reset-device-font-menus):
* package-get.el (package-get-installedp):
* select.el (select-convert-from-image-data):
* sound.el:
* sound.el (load-sound-file):
* x-font-menu.el (x-reset-device-font-menus-core):
Don't quote keywords, they're self-quoting, and the
win from backward-compatibility is sufficiently small now that the
style problem overrides it.
2011-01-22 Aidan Kehoe <kehoea@parhasard.net>
* cl-macs.el (block, return-from): Require that NAME be a symbol
in these macros, as always documented in the #'block docstring and
as required by Common Lisp.
* descr-text.el (unidata-initialize-unihan-database):
Correct the use of non-symbols in #'block and #'return-from in
this function.
2011-01-15 Aidan Kehoe <kehoea@parhasard.net>
* cl-extra.el (concatenate): Accept more complicated TYPEs in this
function, handing the sequences over to #'coerce if we don't
understand them here.
* cl-macs.el (inline): Don't proclaim #'concatenate as inline, its
compiler macro is more useful than doing that.
2011-01-11 Aidan Kehoe <kehoea@parhasard.net>
* subr.el (delete, delq, remove, remq): Move #'remove, #'remq
here, they don't belong in cl-seq.el; move #'delete, #'delq here
from fns.c, implement them in terms of #'delete*, allowing support
for sequences generally.
* update-elc.el (do-autoload-commands): Use #'delete*, not #'delq
here, now the latter's no longer dumped.
* cl-macs.el (delete, delq): Add compiler macros transforming
#'delete and #'delq to #'delete* calls.
2011-01-10 Aidan Kehoe <kehoea@parhasard.net>
* dialog.el (make-dialog-box): Correct a misplaced parenthesis
here, thank you Mats Lidell in 87zkr9gqrh.fsf@mail.contactor.se !
2011-01-02 Aidan Kehoe <kehoea@parhasard.net>
* dialog.el (make-dialog-box):
* list-mode.el (display-completion-list):
These functions used to use cl-parsing-keywords; change them to
use defun* instead, fixing the build. (Not sure what led to me
not including this change in d1b17a33450b!)
2011-01-02 Aidan Kehoe <kehoea@parhasard.net>
* cl-macs.el (define-star-compiler-macros):
Make sure the form has ITEM and LIST specified before attempting
to change to calls with explicit tests; necessary for some tests
in lisp-tests.el to compile correctly.
(stable-union, stable-intersection): Add compiler macros for these
functions, in the same way we do for most of the other functions
in cl-seq.el.
2011-01-01 Aidan Kehoe <kehoea@parhasard.net>
* cl-macs.el (dolist, dotimes, do-symbols, macrolet)
(symbol-macrolet):
Define these macros with defmacro* instead of parsing the argument
list by hand, for the sake of style and readability; use backquote
where appropriate, instead of calling #'list and and friends, for
the same reason.
2010-12-30 Aidan Kehoe <kehoea@parhasard.net>
* x-misc.el (device-x-display):
Provide this function, documented in the Lispref for years, but
not existing previously. Thank you Julian Bradfield, thank you
Jeff Mincy.
2010-12-30 Aidan Kehoe <kehoea@parhasard.net>
* cl-seq.el:
Move the heavy lifting from this file to C. Dump the
cl-parsing-keywords macro, but don't use defun* for the functions
we define that do take keywords, dynamic scope lossage makes that
not practical.
* subr.el (sort, fillarray): Move these aliases here.
(map-plist): #'nsublis is now built-in, but at this point #'eql
isn't necessarily available as a test; use #'eq.
* obsolete.el (cl-delete-duplicates): Make this available for old
compiler macros and old code.
(memql): Document that this is equivalent to #'member*, and worse.
* cl.el (adjoin, subst): Removed. These are in C.
2010-12-30 Aidan Kehoe <kehoea@parhasard.net>
* simple.el (assoc-ignore-case): Remove a duplicate definition of
this function (it's already in subr.el).
* iso8859-1.el (char-width):
On non-Mule, make this function equivalent to that produced by
(constantly 1), but preserve its docstring.
* subr.el (subst-char-in-string): Define this in terms of
#'substitute, #'nsubstitute.
(string-width): Define this using #'reduce and #'char-width.
(char-width): Give this a simpler definition, it makes far more
sense to check for mule at load time and redefine, as we do in
iso8859-1.el.
(store-substring): Implement this in terms of #'replace, now
#'replace is cheap.
2010-12-30 Aidan Kehoe <kehoea@parhasard.net>
* update-elc.el (lisp-files-needed-for-byte-compilation)
(lisp-files-needing-early-byte-compilation):
cl-macs belongs in the former, not the latter, it is as
fundamental as bytecomp.el.
2010-12-30 Aidan Kehoe <kehoea@parhasard.net>
* cl.el:
Provde the Common Lisp program-error, type-error as error
symbols. This doesn't nearly go far enough for anyone using the
Common Lisp errors.
2010-12-29 Aidan Kehoe <kehoea@parhasard.net>
* cl-macs.el (delete-duplicates):
If the form has an incorrect number of arguments, don't attempt a
compiler macroexpansion.
2010-12-29 Aidan Kehoe <kehoea@parhasard.net>
* cl-macs.el (cl-safe-expr-p):
Forms that start with the symbol lambda are also safe.
2010-12-29 Aidan Kehoe <kehoea@parhasard.net>
* cl-macs.el (= < > <= >=):
For these functions' compiler macros, the optimisation is safe
even if the first and the last arguments have side effects, since
they're only used the once.
2010-12-29 Aidan Kehoe <kehoea@parhasard.net>
* cl-macs.el (inline-side-effect-free-compiler-macros):
Unroll a loop here at macro-expansion time, so these compiler
macros are compiled. Use #'eql instead of #'eq in a couple of
places for better style.
2010-12-29 Aidan Kehoe <kehoea@parhasard.net>
* cl-extra.el (notany, notevery): Avoid some dynamic scope
stupidity with local variable names in these functions, when they
weren't prefixed with cl-; go into some more detail in the doc
strings.
2010-12-29 Aidan Kehoe <kehoea@parhasard.net>
* byte-optimize.el (side-effect-free-fns): #'remove, #'remq are
free of side-effects.
(side-effect-and-error-free-fns):
Drop dot, dot-marker from the list.
2010-11-17 Aidan Kehoe <kehoea@parhasard.net>
* cl-extra.el (coerce):
In the argument list, name the first argument OBJECT, not X; the
former name was always used in the doc string and is clearer.
Handle vector type specifications which include the length of the
target sequence, error if there's a mismatch.
* cl-macs.el (cl-make-type-test): Handle type specifications
starting with the symbol 'eql.
2010-11-14 Aidan Kehoe <kehoea@parhasard.net>
* cl-macs.el (eql): Don't remove the byte-compile property of this
symbol. That was necessary to override a bug in bytecomp.el where
#'eql was confused with #'eq, which bug we no longer have.
If neither expression is constant, don't attempt to handle the
expression in this compiler macro, leave it to byte-compile-eql,
which produces better code anyway.
* bytecomp.el (eq): #'eql is not the function associated with the
byte-eq byte code.
(byte-compile-eql): Add an explicit compile method for this
function, for cases where the cl-macs compiler macro hasn't
reduced it to #'eq or #'equal.
2010-10-25 Aidan Kehoe <kehoea@parhasard.net>
Add compiler macros and compilation sanity-checking for various
functions that take keywords.
* byte-optimize.el (side-effect-free-fns): #'symbol-value is
side-effect free and not error free.
* bytecomp.el (byte-compile-normal-call): Check keyword argument
lists for sanity; store information about the positions where
keyword arguments start using the new byte-compile-keyword-start
property.
* cl-macs.el (cl-const-expr-val): Take a new optional argument,
cl-not-constant, defaulting to nil, in this function; return it if
the expression is not constant.
(cl-non-fixnum-number-p): Make this into a separate function, we
want to pass it to #'every.
(eql): Use it.
(define-star-compiler-macros): Use the same code to generate the
member*, assoc* and rassoc* compiler macros; special-case some
code in #'add-to-list in subr.el.
(remove, remq): Add compiler macros for these two functions, in
preparation for #'remove being in C.
(define-foo-if-compiler-macros): Transform (remove-if-not ...) calls to
(remove ... :if-not) at compile time, which will be a real win
once the latter is in C.
(define-substitute-if-compiler-macros)
(define-subst-if-compiler-macros): Similarly for these functions.
(delete-duplicates): Change this compiler macro to use
#'plists-equal; if we don't have information about the type of
SEQUENCE at compile time, don't bother attempting to inline the
call, the function will be in C soon enough.
(equalp): Remove an old commented-out compiler macro for this, if
we want to see it it's in version control.
(subst-char-in-string): Transform this to a call to nsubstitute or
nsubstitute, if that is appropriate.
* cl.el (ldiff): Don't call setf here, this makes for a load-time
dependency problem in cl-macs.el
2010-06-14 Stephen J. Turnbull <stephen@xemacs.org>
* term/vt100.el:
Refer to XEmacs, not GNU Emacs, in permissions.
* term/bg-mouse.el:
* term/sup-mouse.el:
Put copyright notice in canonical "Copyright DATE AUTHOR" form.
Refer to XEmacs, not GNU Emacs, in permissions.
* site-load.el:
Add permission boilerplate.
* mule/canna-leim.el:
* alist.el:
Refer to XEmacs, not APEL/this program, in permissions.
* mule/canna-leim.el:
Remove my copyright, I've assigned it to the FSF.
2010-06-14 Stephen J. Turnbull <stephen@xemacs.org>
* gtk.el:
* gtk-widget-accessors.el:
* gtk-package.el:
* gtk-marshal.el:
* gtk-compose.el:
* gnome.el:
Add copyright notice based on internal evidence.
2010-06-14 Stephen J. Turnbull <stephen@xemacs.org>
* easymenu.el: Add reference to COPYING to permission notice.
* gutter.el:
* gutter-items.el:
* menubar-items.el:
Fix typo "Xmacs" in permissions notice.
2010-06-14 Stephen J. Turnbull <stephen@xemacs.org>
* auto-save.el:
* font.el:
* fontconfig.el:
* mule/kinsoku.el:
Add "part of XEmacs" text to permission notice.
2010-10-14 Aidan Kehoe <kehoea@parhasard.net>
* byte-optimize.el (side-effect-free-fns):
* cl-macs.el (remf, getf):
* cl-extra.el (tailp, cl-set-getf, cl-do-remf):
* cl.el (ldiff, endp):
Tighten up Common Lisp compatibility for #'ldiff, #'endp, #'tailp;
add circularity checking for the first two.
#'cl-set-getf and #'cl-do-remf were Lisp implementations of
#'plist-put and #'plist-remprop; change the names to aliases,
changes the macros that use them to using #'plist-put and
#'plist-remprop directly.
2010-10-12 Aidan Kehoe <kehoea@parhasard.net>
* abbrev.el (fundamental-mode-abbrev-table, global-abbrev-table):
Create both these abbrev tables using the usual
#'define-abbrev-table calls, rather than attempting to
special-case them.
* cl-extra.el: Force cl-macs to be loaded here, if cl-extra.el is
being loaded interpreted. Previously other, later files would
redundantly call (load "cl-macs") when interpreted, it's more
reasonable to do it here, once.
* cmdloop.el (read-quoted-char-radix): Use defcustom here, we
don't have any dump-order dependencies that would prevent that.
* custom.el (eval-when-compile): Don't load cl-macs when
interpreted or when byte-compiling, rely on cl-extra.el in the
former case and the appropriate entry in bytecomp-load-hook in the
latter. Get rid of custom-declare-variable-list, we have no
dump-time dependencies that would require it.
* faces.el (eval-when-compile): Don't load cl-macs when
interpreted or when byte-compiling.
* packages.el: Remove some inaccurate comments.
* post-gc.el (cleanup-simple-finalizers): Use #'delete-if-not
here, now the order of preloaded-file-list has been changed to
make it available.
* subr.el (custom-declare-variable-list): Remove. No need for it.
Also remove a stub define-abbrev-table from this file, given the
current order of preloaded-file-list there's no need for it.
2010-10-10 Aidan Kehoe <kehoea@parhasard.net>
* bytecomp.el (byte-compile-constp) Forms quoted with FUNCTION are
also constant.
(byte-compile-initial-macro-environment): In #'the, if FORM is
constant and does not match TYPE, warn at byte-compile time.
2010-10-10 Aidan Kehoe <kehoea@parhasard.net>
* backquote.el (bq-vector-contents, bq-list*): Remove; the former
is equivalent to (append VECTOR nil), the latter to (list* ...).
(bq-process-2): Use (append VECTOR nil) instead of using
#'bq-vector-contents to convert to a list.
(bq-process-1): Now we use list* instead of bq-list
* subr.el (list*): Moved from cl.el, since it is now required to
be available the first time a backquoted form is encountered.
* cl.el (list*): Move to subr.el.
2010-09-16 Aidan Kehoe <kehoea@parhasard.net>
* test-harness.el (Check-Message):
Add an omitted comma here, thank you the buildbot.
2010-09-16 Aidan Kehoe <kehoea@parhasard.net>
* hash-table.el (hash-table-key-list, hash-table-value-list)
(hash-table-key-value-alist, hash-table-key-value-plist):
Remove some useless #'nreverse calls in these files; our hash
tables have no order, it's not helpful to pretend they do.
* behavior.el (read-behavior):
Do the same in this file, in some code evidently copied from
hash-table.el.
2010-09-16 Aidan Kehoe <kehoea@parhasard.net>
* info.el (Info-insert-dir):
* format.el (format-deannotate-region):
* files.el (cd, save-buffers-kill-emacs):
Use #'some, #'every and related functions for applying boolean
operations to lists, instead of rolling our own ones that cons and
don't short-circuit.
2010-09-16 Aidan Kehoe <kehoea@parhasard.net>
* bytecomp.el (byte-compile-initial-macro-environment):
* cl-macs.el (the):
Rephrase the docstring, make its implementation when compiling
files a little nicer.
2010-09-16 Aidan Kehoe <kehoea@parhasard.net>
* descr-text.el (unidata-initialize-unicodedata-database)
(unidata-initialize-unihan-database, describe-char-unicode-data)
(describe-char-unicode-data):
Wrap calls to the database functions with (with-fboundp ...),
avoiding byte compile warnings on builds without support for the
database functions.
(describe-char): (reduce #'max ...), not (apply #'max ...), no
need to cons needlessly.
(describe-char): Remove a redundant lambda wrapping
#'extent-properties.
(describe-char-unicode-data): Call #'nsubst when replacing "" with
nil in the result of #'split-string, instead of consing inside
mapcar.
2010-09-16 Aidan Kehoe <kehoea@parhasard.net>
* x-faces.el (x-available-font-sizes):
* specifier.el (let-specifier):
* package-ui.el (pui-add-required-packages):
* msw-faces.el (mswindows-available-font-sizes):
* modeline.el (modeline-minor-mode-menu):
* minibuf.el (minibuf-directory-files):
Replace the O2N (delq nil (mapcar (lambda (W) (and X Y)) Z)) with
the ON (mapcan (lambda (W) (and X (list Y))) Z) in these files.
2010-09-16 Aidan Kehoe <kehoea@parhasard.net>
* cl-macs.el (= < > <= >=):
When these functions are handed more than two arguments, and those
arguments have no side effects, transform to a series of two
argument calls, avoiding funcall in the byte-compiled code.
* mule/mule-cmds.el (finish-set-language-environment):
Take advantage of this change in a function called 256 times at
startup.
2010-09-16 Aidan Kehoe <kehoea@parhasard.net>
* bytecomp.el (byte-compile-function-form, byte-compile-quote)
(byte-compile-quote-form):
Warn at compile time, and error at runtime, if a (quote ...) or a
(function ...) form attempts to quote more than one object.
2010-09-16 Aidan Kehoe <kehoea@parhasard.net>
* byte-optimize.el (byte-optimize-apply): Transform (apply 'nconc
(mapcar ...)) to (mapcan ...); warn about use of the first idiom.
* update-elc.el (do-autoload-commands):
* packages.el (packages-find-package-library-path):
* frame.el (frame-list):
* extents.el (extent-descendants):
* etags.el (buffer-tag-table-files):
* dumped-lisp.el (preloaded-file-list):
* device.el (device-list):
* bytecomp-runtime.el (proclaim-inline, proclaim-notinline)
Use #'mapcan, not (apply #'nconc (mapcar ...) in all these files.
* bytecomp-runtime.el (eval-when-compile, eval-and-compile):
In passing, mention that these macros also evaluate the body when
interpreted.
tests/ChangeLog addition:
2011-02-07 Aidan Kehoe <kehoea@parhasard.net>
* automated/lisp-tests.el:
Test lexical scope for `block', `return-from'; add a
Known-Bug-Expect-Failure for a contorted example that fails when
byte-compiled.
| author | Aidan Kehoe <kehoea@parhasard.net> |
|---|---|
| date | Mon, 07 Feb 2011 12:01:24 +0000 |
| parents | 956d54c39176 |
| children | 62b9ef1ed4ac |
| 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{} |
|
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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 variable, local to a given buffer, reflects the number of times |
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710 XEmacs has displayed the buffer in a window. |
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711 @end defvar |
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712 |
| 428 | 713 @defun window-buffer &optional window |
| 714 This function returns the buffer that @var{window} is displaying. If | |
| 715 @var{window} is omitted, this function returns the buffer for the | |
| 716 selected window. | |
| 717 | |
| 718 @example | |
| 719 @group | |
| 720 (window-buffer) | |
| 721 @result{} #<buffer windows.texi> | |
| 722 @end group | |
| 723 @end example | |
| 724 @end defun | |
| 725 | |
| 444 | 726 @defun get-buffer-window buffer-or-name &optional which-frames which-devices |
| 428 | 727 This function returns a window currently displaying |
| 728 @var{buffer-or-name}, or @code{nil} if there is none. If there are | |
| 729 several such windows, then the function returns the first one in the | |
| 730 cyclic ordering of windows, starting from the selected window. | |
| 731 @xref{Cyclic Window Ordering}. | |
| 732 | |
| 444 | 733 The remaining arguments control which windows to consider. They have |
| 734 the same meaning as for @code{next-window}. | |
| 428 | 735 @end defun |
| 736 | |
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737 |
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738 @defvar buffer-display-time |
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739 This variable records the time at which a buffer was last made visible |
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740 in a window. It is always local in each buffer; each time |
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741 @code{set-window-buffer} is called, it sets this variable to |
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742 @code{(current-time)} in the specified buffer (@pxref{Time of Day}). |
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743 When a buffer is first created, @code{buffer-display-time} starts out |
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744 with the value @code{nil}. |
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745 @end defvar |
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746 |
| 428 | 747 @node Displaying Buffers |
| 748 @section Displaying Buffers in Windows | |
| 749 @cindex switching to a buffer | |
| 750 @cindex displaying a buffer | |
| 751 | |
| 752 In this section we describe convenient functions that choose a window | |
| 753 automatically and use it to display a specified buffer. These functions | |
| 754 can also split an existing window in certain circumstances. We also | |
| 755 describe variables that parameterize the heuristics used for choosing a | |
| 756 window. | |
| 757 @iftex | |
| 758 See the preceding section for | |
| 759 @end iftex | |
| 760 @ifinfo | |
| 761 @xref{Buffers and Windows}, for | |
| 762 @end ifinfo | |
| 763 low-level functions that give you more precise control. | |
| 764 | |
| 765 Do not use the functions in this section in order to make a buffer | |
| 766 current so that a Lisp program can access or modify it; they are too | |
| 767 drastic for that purpose, since they change the display of buffers in | |
| 768 windows, which is gratuitous and will surprise the user. Instead, use | |
| 769 @code{set-buffer} (@pxref{Current Buffer}) and @code{save-excursion} | |
| 770 (@pxref{Excursions}), which designate buffers as current for programmed | |
| 771 access without affecting the display of buffers in windows. | |
| 772 | |
| 773 @deffn Command switch-to-buffer buffer-or-name &optional norecord | |
| 774 This function makes @var{buffer-or-name} the current buffer, and also | |
| 775 displays the buffer in the selected window. This means that a human can | |
| 776 see the buffer and subsequent keyboard commands will apply to it. | |
| 777 Contrast this with @code{set-buffer}, which makes @var{buffer-or-name} | |
| 778 the current buffer but does not display it in the selected window. | |
| 779 @xref{Current Buffer}. | |
| 780 | |
| 781 If @var{buffer-or-name} does not identify an existing buffer, then a new | |
| 782 buffer by that name is created. The major mode for the new buffer is | |
| 783 set according to the variable @code{default-major-mode}. @xref{Auto | |
| 784 Major Mode}. | |
| 785 | |
| 786 Normally the specified buffer is put at the front of the buffer list. | |
| 787 This affects the operation of @code{other-buffer}. However, if | |
| 788 @var{norecord} is non-@code{nil}, this is not done. @xref{The Buffer | |
| 789 List}. | |
| 790 | |
| 791 The @code{switch-to-buffer} function is often used interactively, as | |
| 792 the binding of @kbd{C-x b}. It is also used frequently in programs. It | |
| 793 always returns @code{nil}. | |
| 794 @end deffn | |
| 795 | |
| 796 @deffn Command switch-to-buffer-other-window buffer-or-name | |
| 797 This function makes @var{buffer-or-name} the current buffer and | |
| 798 displays it in a window not currently selected. It then selects that | |
| 799 window. The handling of the buffer is the same as in | |
| 800 @code{switch-to-buffer}. | |
| 801 | |
| 802 The currently selected window is absolutely never used to do the job. | |
| 803 If it is the only window, then it is split to make a distinct window for | |
| 804 this purpose. If the selected window is already displaying the buffer, | |
| 805 then it continues to do so, but another window is nonetheless found to | |
| 806 display it in as well. | |
| 807 @end deffn | |
| 808 | |
| 809 @defun pop-to-buffer buffer-or-name &optional other-window on-frame | |
| 810 This function makes @var{buffer-or-name} the current buffer and | |
| 811 switches to it in some window, preferably not the window previously | |
| 812 selected. The ``popped-to'' window becomes the selected window within | |
| 813 its frame. | |
| 814 | |
| 815 If the variable @code{pop-up-frames} is non-@code{nil}, | |
| 816 @code{pop-to-buffer} looks for a window in any visible frame already | |
| 817 displaying the buffer; if there is one, it returns that window and makes | |
| 818 it be selected within its frame. If there is none, it creates a new | |
| 819 frame and displays the buffer in it. | |
| 820 | |
| 821 If @code{pop-up-frames} is @code{nil}, then @code{pop-to-buffer} | |
| 822 operates entirely within the selected frame. (If the selected frame has | |
| 823 just a minibuffer, @code{pop-to-buffer} operates within the most | |
| 824 recently selected frame that was not just a minibuffer.) | |
| 825 | |
| 826 If the variable @code{pop-up-windows} is non-@code{nil}, windows may | |
| 827 be split to create a new window that is different from the original | |
| 828 window. For details, see @ref{Choosing Window}. | |
| 829 | |
| 830 If @var{other-window} is non-@code{nil}, @code{pop-to-buffer} finds or | |
| 831 creates another window even if @var{buffer-or-name} is already visible | |
| 832 in the selected window. Thus @var{buffer-or-name} could end up | |
| 833 displayed in two windows. On the other hand, if @var{buffer-or-name} is | |
| 834 already displayed in the selected window and @var{other-window} is | |
| 835 @code{nil}, then the selected window is considered sufficient display | |
| 836 for @var{buffer-or-name}, so that nothing needs to be done. | |
| 837 | |
| 838 All the variables that affect @code{display-buffer} affect | |
| 839 @code{pop-to-buffer} as well. @xref{Choosing Window}. | |
| 840 | |
| 841 If @var{buffer-or-name} is a string that does not name an existing | |
| 842 buffer, a buffer by that name is created. The major mode for the new | |
| 843 buffer is set according to the variable @code{default-major-mode}. | |
| 844 @xref{Auto Major Mode}. | |
| 845 | |
| 846 If @var{on-frame} is non-@code{nil}, it is the frame to pop to this | |
| 847 buffer on. | |
| 848 | |
| 849 An example use of this function is found at the end of @ref{Filter | |
| 850 Functions}. | |
| 851 @end defun | |
| 852 | |
| 444 | 853 @deffn Command replace-buffer-in-windows buffer &optional which-frames which-devices |
| 428 | 854 This function replaces @var{buffer} with some other buffer in all |
| 855 windows displaying it. The other buffer used is chosen with | |
| 856 @code{other-buffer}. In the usual applications of this function, you | |
| 857 don't care which other buffer is used; you just want to make sure that | |
| 858 @var{buffer} is no longer displayed. | |
| 859 | |
| 444 | 860 The optional arguments @var{which-frames} and @var{which-devices} have |
| 861 the same meaning as with @code{delete-windows-on}. | |
| 862 | |
| 428 | 863 This function returns @code{nil}. |
| 864 @end deffn | |
| 865 | |
| 866 @node Choosing Window | |
| 867 @section Choosing a Window for Display | |
| 868 | |
| 869 This section describes the basic facility that chooses a window to | |
| 870 display a buffer in---@code{display-buffer}. All the higher-level | |
| 871 functions and commands use this subroutine. Here we describe how to use | |
| 872 @code{display-buffer} and how to customize it. | |
| 873 | |
| 444 | 874 @deffn Command display-buffer buffer-or-name &optional not-this-window override-frame |
| 428 | 875 This command makes @var{buffer-or-name} appear in some window, like |
| 876 @code{pop-to-buffer}, but it does not select that window and does not | |
| 877 make the buffer current. The identity of the selected window is | |
| 878 unaltered by this function. | |
| 879 | |
| 444 | 880 @var{buffer-or-name} can be a buffer or the name of one. |
| 881 | |
| 428 | 882 If @var{not-this-window} is non-@code{nil}, it means to display the |
| 883 specified buffer in a window other than the selected one, even if it is | |
| 884 already on display in the selected window. This can cause the buffer to | |
| 885 appear in two windows at once. Otherwise, if @var{buffer-or-name} is | |
| 886 already being displayed in any window, that is good enough, so this | |
| 887 function does nothing. | |
| 888 | |
| 444 | 889 If @var{override-frame} is non-@code{nil}, display on that frame instead |
| 890 of the current frame (or the dedicated frame). | |
| 891 | |
| 892 @code{display-buffer} returns the window chosen to display @var{buffer-or-name}. | |
| 428 | 893 |
| 894 Precisely how @code{display-buffer} finds or creates a window depends on | |
| 895 the variables described below. | |
| 896 @end deffn | |
| 897 | |
| 898 @c Emacs 19 feature | |
| 899 @cindex dedicated window | |
| 900 A window can be marked as ``dedicated'' to a particular buffer. | |
| 901 Then XEmacs will not automatically change which buffer appears in the | |
| 902 window, such as @code{display-buffer} might normally do. | |
| 903 | |
| 904 @defun window-dedicated-p window | |
| 905 This function returns @var{window}'s dedicated object, usually @code{t} | |
| 906 or @code{nil}. | |
| 907 @end defun | |
| 908 | |
| 909 @defun set-window-buffer-dedicated window buffer | |
| 910 This function makes @var{window} display @var{buffer} and be dedicated | |
| 911 to that buffer. Then XEmacs will not automatically change which buffer | |
| 912 appears in @var{window}. If @var{buffer} is @code{nil}, this function makes | |
| 913 @var{window} not be dedicated (but doesn't change which buffer appears | |
| 914 in it currently). | |
| 915 @end defun | |
| 916 | |
| 917 @defopt pop-up-windows | |
| 918 This variable controls whether @code{display-buffer} makes new windows. | |
| 919 If it is non-@code{nil} and there is only one window, then that window | |
| 920 is split. If it is @code{nil}, then @code{display-buffer} does not | |
| 921 split the single window, but uses it whole. | |
| 922 @end defopt | |
| 923 | |
| 924 @defopt split-height-threshold | |
| 925 This variable determines when @code{display-buffer} may split a window, | |
| 926 if there are multiple windows. @code{display-buffer} always splits the | |
| 927 largest window if it has at least this many lines. If the largest | |
| 928 window is not this tall, it is split only if it is the sole window and | |
| 929 @code{pop-up-windows} is non-@code{nil}. | |
| 930 @end defopt | |
| 931 | |
| 932 @c Emacs 19 feature | |
| 933 @defopt pop-up-frames | |
| 934 This variable controls whether @code{display-buffer} makes new frames. | |
| 935 If it is non-@code{nil}, @code{display-buffer} looks for an existing | |
| 936 window already displaying the desired buffer, on any visible frame. If | |
| 937 it finds one, it returns that window. Otherwise it makes a new frame. | |
| 938 The variables @code{pop-up-windows} and @code{split-height-threshold} do | |
| 939 not matter if @code{pop-up-frames} is non-@code{nil}. | |
| 940 | |
| 941 If @code{pop-up-frames} is @code{nil}, then @code{display-buffer} either | |
| 942 splits a window or reuses one. | |
| 943 | |
| 944 @xref{Frames}, for more information. | |
| 945 @end defopt | |
| 946 | |
| 947 @c Emacs 19 feature | |
| 948 @defvar pop-up-frame-function | |
| 949 This variable specifies how to make a new frame if @code{pop-up-frames} | |
| 950 is non-@code{nil}. | |
| 951 | |
| 952 Its value should be a function of no arguments. When | |
| 953 @code{display-buffer} makes a new frame, it does so by calling that | |
| 954 function, which should return a frame. The default value of the | |
| 955 variable is a function that creates a frame using properties from | |
| 956 @code{pop-up-frame-plist}. | |
| 957 @end defvar | |
| 958 | |
| 959 @defvar pop-up-frame-plist | |
| 960 This variable holds a plist specifying frame properties used when | |
| 961 @code{display-buffer} makes a new frame. @xref{Frame Properties}, for | |
| 962 more information about frame properties. | |
| 963 @end defvar | |
| 964 | |
| 965 @defvar special-display-buffer-names | |
| 966 A list of buffer names for buffers that should be displayed specially. | |
| 967 If the buffer's name is in this list, @code{display-buffer} handles the | |
| 968 buffer specially. | |
| 969 | |
| 970 By default, special display means to give the buffer a dedicated frame. | |
| 971 | |
| 972 If an element is a list, instead of a string, then the @sc{car} of the | |
| 973 list is the buffer name, and the rest of the list says how to create the | |
| 974 frame. There are two possibilities for the rest of the list. It can be | |
| 975 a plist, specifying frame properties, or it can contain a function and | |
| 976 arguments to give to it. (The function's first argument is always the | |
| 977 buffer to be displayed; the arguments from the list come after that.) | |
| 978 @end defvar | |
| 979 | |
| 980 @defvar special-display-regexps | |
| 981 A list of regular expressions that specify buffers that should be | |
| 982 displayed specially. If the buffer's name matches any of the regular | |
| 983 expressions in this list, @code{display-buffer} handles the buffer | |
| 984 specially. | |
| 985 | |
| 986 By default, special display means to give the buffer a dedicated frame. | |
| 987 | |
| 988 If an element is a list, instead of a string, then the @sc{car} of the | |
| 989 list is the regular expression, and the rest of the list says how to | |
| 990 create the frame. See above, under @code{special-display-buffer-names}. | |
| 991 @end defvar | |
| 992 | |
| 993 @defvar special-display-function | |
| 994 This variable holds the function to call to display a buffer specially. | |
| 995 It receives the buffer as an argument, and should return the window in | |
| 996 which it is displayed. | |
| 997 | |
| 998 The default value of this variable is | |
| 999 @code{special-display-popup-frame}. | |
| 1000 @end defvar | |
| 1001 | |
| 1002 @defun special-display-popup-frame buffer | |
| 1003 This function makes @var{buffer} visible in a frame of its own. If | |
| 1004 @var{buffer} is already displayed in a window in some frame, it makes | |
| 1005 the frame visible and raises it, to use that window. Otherwise, it | |
| 1006 creates a frame that will be dedicated to @var{buffer}. | |
| 1007 | |
| 1008 This function uses an existing window displaying @var{buffer} whether or | |
| 1009 not it is in a frame of its own; but if you set up the above variables | |
| 1010 in your init file, before @var{buffer} was created, then presumably the | |
| 1011 window was previously made by this function. | |
| 1012 @end defun | |
| 1013 | |
| 1014 @defopt special-display-frame-plist | |
| 1015 This variable holds frame properties for | |
| 1016 @code{special-display-popup-frame} to use when it creates a frame. | |
| 1017 @end defopt | |
| 1018 | |
| 1019 @defvar same-window-buffer-names | |
| 1020 A list of buffer names for buffers that should be displayed in the | |
| 1021 selected window. If the buffer's name is in this list, | |
| 1022 @code{display-buffer} handles the buffer by switching to it in the | |
| 1023 selected window. | |
| 1024 @end defvar | |
| 1025 | |
| 1026 @defvar same-window-regexps | |
| 1027 A list of regular expressions that specify buffers that should be | |
| 1028 displayed in the selected window. If the buffer's name matches any of | |
| 1029 the regular expressions in this list, @code{display-buffer} handles the | |
| 1030 buffer by switching to it in the selected window. | |
| 1031 @end defvar | |
| 1032 | |
| 1033 @c Emacs 19 feature | |
| 1034 @defvar display-buffer-function | |
| 1035 This variable is the most flexible way to customize the behavior of | |
| 1036 @code{display-buffer}. If it is non-@code{nil}, it should be a function | |
| 1037 that @code{display-buffer} calls to do the work. The function should | |
| 1038 accept two arguments, the same two arguments that @code{display-buffer} | |
| 1039 received. It should choose or create a window, display the specified | |
| 1040 buffer, and then return the window. | |
| 1041 | |
| 1042 This hook takes precedence over all the other options and hooks | |
| 1043 described above. | |
| 1044 @end defvar | |
| 1045 | |
| 1046 @c Emacs 19 feature | |
| 1047 @cindex dedicated window | |
| 1048 A window can be marked as ``dedicated'' to its buffer. Then | |
| 1049 @code{display-buffer} does not try to use that window. | |
| 1050 | |
| 1051 @defun window-dedicated-p window | |
| 1052 This function returns @code{t} if @var{window} is marked as dedicated; | |
| 1053 otherwise @code{nil}. | |
| 1054 @end defun | |
| 1055 | |
| 1056 @defun set-window-dedicated-p window flag | |
| 1057 This function marks @var{window} as dedicated if @var{flag} is | |
| 1058 non-@code{nil}, and nondedicated otherwise. | |
| 1059 @end defun | |
| 1060 | |
| 1061 @node Window Point | |
| 1062 @section Windows and Point | |
| 1063 @cindex window position | |
| 1064 @cindex window point | |
| 1065 @cindex position in window | |
| 1066 @cindex point in window | |
| 2289 | 1067 @cindex cursor in window |
| 428 | 1068 |
| 1069 Each window has its own value of point, independent of the value of | |
| 1070 point in other windows displaying the same buffer. This makes it useful | |
| 1071 to have multiple windows showing one buffer. | |
| 1072 | |
| 1073 @itemize @bullet | |
| 1074 @item | |
| 1075 The window point is established when a window is first created; it is | |
| 1076 initialized from the buffer's point, or from the window point of another | |
| 1077 window opened on the buffer if such a window exists. | |
| 1078 | |
| 1079 @item | |
| 1080 Selecting a window sets the value of point in its buffer to the window's | |
| 1081 value of point. Conversely, deselecting a window sets the window's | |
| 1082 value of point from that of the buffer. Thus, when you switch between | |
| 1083 windows that display a given buffer, the point value for the selected | |
| 1084 window is in effect in the buffer, while the point values for the other | |
| 1085 windows are stored in those windows. | |
| 1086 | |
| 1087 @item | |
| 1088 As long as the selected window displays the current buffer, the window's | |
| 1089 point and the buffer's point always move together; they remain equal. | |
| 1090 | |
| 1091 @item | |
| 1092 @xref{Positions}, for more details on buffer positions. | |
| 1093 @end itemize | |
| 1094 | |
| 1095 As far as the user is concerned, point is where the cursor is, and | |
| 1096 when the user switches to another buffer, the cursor jumps to the | |
| 1097 position of point in that buffer. | |
| 1098 | |
| 444 | 1099 @defun window-point &optional window |
| 428 | 1100 This function returns the current position of point in @var{window}. |
| 442 | 1101 For a non-selected window, this is the value point would have (in that |
| 428 | 1102 window's buffer) if that window were selected. |
| 1103 | |
| 1104 When @var{window} is the selected window and its buffer is also the | |
| 444 | 1105 current buffer, the value returned is the same as the value of point in |
| 1106 that buffer. | |
| 428 | 1107 |
| 1108 Strictly speaking, it would be more correct to return the | |
| 1109 ``top-level'' value of point, outside of any @code{save-excursion} | |
| 1110 forms. But that value is hard to find. | |
| 1111 @end defun | |
| 1112 | |
| 1113 @defun set-window-point window position | |
| 1114 This function positions point in @var{window} at position | |
| 1115 @var{position} in @var{window}'s buffer. | |
| 1116 @end defun | |
| 1117 | |
| 2289 | 1118 @defun current-pixel-row &optional window pos |
| 1119 @defunx current-pixel-column &optional window pos | |
| 1120 @cindex cursor pixel row | |
| 1121 @cindex window point pixel row | |
| 1122 @cindex cursor pixel column | |
| 1123 @cindex window point pixel column | |
| 1124 The function, @code{current-pixel-row}, returns the vertical location, | |
| 1125 in pixels, of the point @var{pos} within the specified @var{window}; | |
| 1126 similarly, @code{current-pixel-column} returns the corresponding | |
| 1127 horizontal location. The position returned is that of the upper-left | |
| 1128 corner of the cursor, and is relative to the upper-left location of the | |
| 1129 window. If @var{window} is @code{nil}, the function uses the selected | |
| 1130 window. If @var{pos} is @code{nil}, the value of @code{window-point} is | |
| 1131 used. | |
| 1132 | |
| 1133 Note that the coordinates are relative to the current XEmacs window, and | |
| 1134 are not relative to the XEmacs X11 window. To obtain the coordinates | |
| 1135 relative to the X11 window, you must also take into account the spacings | |
| 1136 of any menubars, gutters, toolbars, margins, etc., as well as any window | |
| 1137 offsets. The function, @code{window-pixel-edges} (@pxref{Position of | |
| 1138 Window}), can be used to help calculate the location relative to the | |
| 1139 frame. | |
| 1140 | |
| 1141 @emph{Important note}: in order for these functions to return a correct, | |
| 1142 non-nil value, two criteria @emph{must} be satisfied: | |
| 1143 | |
| 1144 @itemize @bullet | |
| 1145 | |
| 1146 @item | |
| 1147 The location of @code{pos} must be visible within the specified window. | |
| 1148 If @var{pos} is outside the visible area, @code{nil} is returned. | |
| 1149 | |
| 1150 @item | |
| 1151 As the pixel location is determined from the redisplay tables, the | |
| 1152 redisplay tables must be up-to-date. In other words, the XEmacs | |
| 1153 window(s), as seen by the user, must be correct (to improve performance, | |
| 1154 XEmacs generally defers display updates until control returns back to | |
| 1155 the idle loop). To insure that the redisplay tables are up-to-date, one | |
| 1156 of the following must generally be done @emph{before} calling | |
| 1157 @code{current-pixel-row} or @code{current-pixel-column}: | |
| 1158 | |
| 1159 @itemize @bullet | |
| 1160 | |
| 1161 @item | |
| 1162 If the window in question is not in a new frame, you can force a | |
| 1163 redisplay using @code{(sit-for 0)}. See @code{sit-for} in | |
| 1164 @ref{Waiting}. | |
| 1165 | |
| 1166 @item | |
| 1167 If the window in question is in a new frame, you must call code like the | |
| 1168 following: | |
| 1169 | |
| 1170 @example | |
| 1171 @group | |
| 1172 (while (not (frame-visible-p frame)) | |
| 1173 (sleep-for .5)) | |
| 1174 @end group | |
| 1175 @end example | |
| 1176 | |
| 1177 @end itemize | |
| 1178 | |
| 1179 @end itemize | |
| 1180 | |
| 1181 If one of these is not done, the return value may be incorrect, even if | |
| 1182 it is non-nil. | |
| 1183 | |
| 1184 @end defun | |
| 1185 | |
| 428 | 1186 @node Window Start |
| 1187 @section The Window Start Position | |
| 1188 | |
| 1189 Each window contains a marker used to keep track of a buffer position | |
| 1190 that specifies where in the buffer display should start. This position | |
| 1191 is called the @dfn{display-start} position of the window (or just the | |
| 1192 @dfn{start}). The character after this position is the one that appears | |
| 1193 at the upper left corner of the window. It is usually, but not | |
| 1194 inevitably, at the beginning of a text line. | |
| 1195 | |
| 1196 @defun window-start &optional window | |
| 1197 @cindex window top line | |
| 1198 This function returns the display-start position of window | |
| 1199 @var{window}. If @var{window} is @code{nil}, the selected window is | |
| 444 | 1200 used. For example, |
| 428 | 1201 |
| 1202 @example | |
| 1203 @group | |
| 1204 (window-start) | |
| 1205 @result{} 7058 | |
| 1206 @end group | |
| 1207 @end example | |
| 1208 | |
| 1209 When you create a window, or display a different buffer in it, the | |
| 1210 display-start position is set to a display-start position recently used | |
| 1211 for the same buffer, or 1 if the buffer doesn't have any. | |
| 1212 | |
| 1213 For a realistic example, see the description of @code{count-lines} in | |
| 1214 @ref{Text Lines}. | |
| 1215 @end defun | |
| 1216 | |
| 444 | 1217 @defun window-end &optional window guarantee |
| 428 | 1218 This function returns the position of the end of the display in window |
| 1219 @var{window}. If @var{window} is @code{nil}, the selected window is | |
| 1220 used. | |
| 1221 | |
| 444 | 1222 Simply changing the buffer text or setting @code{window-start} does not |
| 1223 update the value that @code{window-end} returns. The value is updated | |
| 1224 only when Emacs redisplays and redisplay actually finishes. | |
| 428 | 1225 |
| 1226 If the last redisplay of @var{window} was preempted, and did not finish, | |
| 1227 Emacs does not know the position of the end of display in that window. | |
| 1228 In that case, this function returns a value that is not correct. In a | |
| 1229 future version, @code{window-end} will return @code{nil} in that case. | |
| 444 | 1230 |
| 1231 If optional arg @var{guarantee} is non-@code{nil}, the return value is | |
| 1232 guaranteed to be the same as @code{window-end} would return at the end | |
| 1233 of the next full redisplay assuming nothing else changes in the | |
| 1234 meantime. This function is potentially much slower with this flag set. | |
| 1235 | |
| 428 | 1236 @ignore |
| 1237 in that case, this function returns @code{nil}. You can compute where | |
| 1238 the end of the window @emph{would} have been, if redisplay had finished, | |
| 1239 like this: | |
| 1240 | |
| 1241 @example | |
| 1242 (save-excursion | |
| 1243 (goto-char (window-start window)) | |
| 1244 (vertical-motion (1- (window-height window)) | |
| 1245 window) | |
| 1246 (point)) | |
| 1247 @end example | |
| 1248 @end ignore | |
| 1249 @end defun | |
| 1250 | |
| 1251 @defun set-window-start window position &optional noforce | |
| 1252 This function sets the display-start position of @var{window} to | |
| 1253 @var{position} in @var{window}'s buffer. It returns @var{position}. | |
| 1254 | |
| 1255 The display routines insist that the position of point be visible when a | |
| 1256 buffer is displayed. Normally, they change the display-start position | |
| 1257 (that is, scroll the window) whenever necessary to make point visible. | |
| 1258 However, if you specify the start position with this function using | |
| 1259 @code{nil} for @var{noforce}, it means you want display to start at | |
| 1260 @var{position} even if that would put the location of point off the | |
| 1261 screen. If this does place point off screen, the display routines move | |
| 1262 point to the left margin on the middle line in the window. | |
| 1263 | |
| 1264 For example, if point @w{is 1} and you set the start of the window @w{to | |
| 1265 2}, then point would be ``above'' the top of the window. The display | |
| 1266 routines will automatically move point if it is still 1 when redisplay | |
| 1267 occurs. Here is an example: | |
| 1268 | |
| 1269 @example | |
| 1270 @group | |
| 1271 ;; @r{Here is what @samp{foo} looks like before executing} | |
| 1272 ;; @r{the @code{set-window-start} expression.} | |
| 1273 @end group | |
| 1274 | |
| 1275 @group | |
| 1276 ---------- Buffer: foo ---------- | |
| 1277 @point{}This is the contents of buffer foo. | |
| 1278 2 | |
| 1279 3 | |
| 1280 4 | |
| 1281 5 | |
| 1282 6 | |
| 1283 ---------- Buffer: foo ---------- | |
| 1284 @end group | |
| 1285 | |
| 1286 @group | |
| 1287 (set-window-start | |
| 1288 (selected-window) | |
| 1289 (1+ (window-start))) | |
| 1290 @result{} 2 | |
| 1291 @end group | |
| 1292 | |
| 1293 @group | |
| 1294 ;; @r{Here is what @samp{foo} looks like after executing} | |
| 1295 ;; @r{the @code{set-window-start} expression.} | |
| 1296 ---------- Buffer: foo ---------- | |
| 1297 his is the contents of buffer foo. | |
| 1298 2 | |
| 1299 3 | |
| 1300 @point{}4 | |
| 1301 5 | |
| 1302 6 | |
| 1303 ---------- Buffer: foo ---------- | |
| 1304 @end group | |
| 1305 @end example | |
| 1306 | |
| 1307 If @var{noforce} is non-@code{nil}, and @var{position} would place point | |
| 1308 off screen at the next redisplay, then redisplay computes a new window-start | |
| 1309 position that works well with point, and thus @var{position} is not used. | |
| 1310 @end defun | |
| 1311 | |
| 1312 @defun pos-visible-in-window-p &optional position window | |
| 1313 This function returns @code{t} if @var{position} is within the range | |
| 1314 of text currently visible on the screen in @var{window}. It returns | |
| 1315 @code{nil} if @var{position} is scrolled vertically out of view. The | |
| 1316 argument @var{position} defaults to the current position of point; | |
| 1317 @var{window}, to the selected window. Here is an example: | |
| 1318 | |
| 1319 @example | |
| 1320 @group | |
| 1321 (or (pos-visible-in-window-p | |
| 1322 (point) (selected-window)) | |
| 1323 (recenter 0)) | |
| 1324 @end group | |
| 1325 @end example | |
| 1326 | |
| 1327 The @code{pos-visible-in-window-p} function considers only vertical | |
| 1328 scrolling. If @var{position} is out of view only because @var{window} | |
| 1329 has been scrolled horizontally, @code{pos-visible-in-window-p} returns | |
| 1330 @code{t}. @xref{Horizontal Scrolling}. | |
| 1331 @end defun | |
| 1332 | |
| 1333 @node Vertical Scrolling | |
| 1334 @section Vertical Scrolling | |
| 1335 @cindex vertical scrolling | |
| 1336 @cindex scrolling vertically | |
| 1337 | |
| 1338 Vertical scrolling means moving the text up or down in a window. It | |
| 1339 works by changing the value of the window's display-start location. It | |
| 1340 may also change the value of @code{window-point} to keep it on the | |
| 1341 screen. | |
| 1342 | |
| 1343 In the commands @code{scroll-up} and @code{scroll-down}, the directions | |
| 1344 ``up'' and ``down'' refer to the motion of the text in the buffer at which | |
| 1345 you are looking through the window. Imagine that the text is | |
| 1346 written on a long roll of paper and that the scrolling commands move the | |
| 1347 paper up and down. Thus, if you are looking at text in the middle of a | |
| 1348 buffer and repeatedly call @code{scroll-down}, you will eventually see | |
| 1349 the beginning of the buffer. | |
| 1350 | |
| 1351 Some people have urged that the opposite convention be used: they | |
| 1352 imagine that the window moves over text that remains in place. Then | |
| 1353 ``down'' commands would take you to the end of the buffer. This view is | |
| 1354 more consistent with the actual relationship between windows and the | |
| 1355 text in the buffer, but it is less like what the user sees. The | |
| 1356 position of a window on the terminal does not move, and short scrolling | |
| 1357 commands clearly move the text up or down on the screen. We have chosen | |
| 1358 names that fit the user's point of view. | |
| 1359 | |
| 1360 The scrolling functions (aside from @code{scroll-other-window}) have | |
| 1361 unpredictable results if the current buffer is different from the buffer | |
| 1362 that is displayed in the selected window. @xref{Current Buffer}. | |
| 1363 | |
| 444 | 1364 @deffn Command scroll-up &optional lines |
| 428 | 1365 This function scrolls the text in the selected window upward |
| 444 | 1366 @var{lines} lines. If @var{lines} is negative, scrolling is actually |
| 428 | 1367 downward. |
| 1368 | |
| 444 | 1369 If @var{lines} is @code{nil} (or omitted), then the length of scroll |
| 428 | 1370 is @code{next-screen-context-lines} lines less than the usable height of |
| 1371 the window (not counting its modeline). | |
| 1372 | |
| 1373 @code{scroll-up} returns @code{nil}. | |
| 1374 @end deffn | |
| 1375 | |
| 444 | 1376 @deffn Command scroll-down &optional lines |
| 428 | 1377 This function scrolls the text in the selected window downward |
| 444 | 1378 @var{lines} lines. If @var{lines} is negative, scrolling is actually |
| 428 | 1379 upward. |
| 1380 | |
| 444 | 1381 If @var{lines} is omitted or @code{nil}, then the length of the scroll |
| 428 | 1382 is @code{next-screen-context-lines} lines less than the usable height of |
| 1383 the window (not counting its mode line). | |
| 1384 | |
| 1385 @code{scroll-down} returns @code{nil}. | |
| 1386 @end deffn | |
| 1387 | |
| 444 | 1388 @deffn Command scroll-other-window &optional lines |
| 1389 This function scrolls the text in another window upward @var{lines} | |
| 1390 lines. Negative values of @var{lines}, or @code{nil}, are handled | |
| 428 | 1391 as in @code{scroll-up}. |
| 1392 | |
| 1393 You can specify a buffer to scroll with the variable | |
| 1394 @code{other-window-scroll-buffer}. When the selected window is the | |
| 1395 minibuffer, the next window is normally the one at the top left corner. | |
| 1396 You can specify a different window to scroll with the variable | |
| 1397 @code{minibuffer-scroll-window}. This variable has no effect when any | |
| 1398 other window is selected. @xref{Minibuffer Misc}. | |
| 1399 | |
| 1400 When the minibuffer is active, it is the next window if the selected | |
| 1401 window is the one at the bottom right corner. In this case, | |
| 1402 @code{scroll-other-window} attempts to scroll the minibuffer. If the | |
| 1403 minibuffer contains just one line, it has nowhere to scroll to, so the | |
| 1404 line reappears after the echo area momentarily displays the message | |
| 1405 ``Beginning of buffer''. | |
| 1406 @end deffn | |
| 1407 | |
| 1408 @c Emacs 19 feature | |
| 1409 @defvar other-window-scroll-buffer | |
| 1410 If this variable is non-@code{nil}, it tells @code{scroll-other-window} | |
| 1411 which buffer to scroll. | |
| 1412 @end defvar | |
| 1413 | |
| 1414 @defopt scroll-step | |
| 1415 This variable controls how scrolling is done automatically when point | |
| 1416 moves off the screen. If the value is zero, then redisplay scrolls the | |
| 1417 text to center point vertically in the window. If the value is a | |
| 1418 positive integer @var{n}, then redisplay brings point back on screen by | |
| 1419 scrolling @var{n} lines in either direction, if possible; otherwise, it | |
| 1420 centers point. The default value is zero. | |
| 1421 @end defopt | |
| 1422 | |
| 1423 @defopt scroll-conservatively | |
| 1424 This variable controls how many lines Emacs tries to scroll before | |
| 1425 recentering. If you set it to a small number, then when you move point | |
| 1426 a short distance off the screen, XEmacs will scroll the screen just far | |
| 1427 enough to bring point back on screen, provided that does not exceed | |
| 1428 @code{scroll-conservatively} lines. This variable overrides the | |
| 1429 redisplay preemption. | |
| 1430 @end defopt | |
| 1431 | |
| 1432 @defopt next-screen-context-lines | |
| 1433 The value of this variable is the number of lines of continuity to | |
| 1434 retain when scrolling by full screens. For example, @code{scroll-up} | |
| 1435 with an argument of @code{nil} scrolls so that this many lines at the | |
| 1436 bottom of the window appear instead at the top. The default value is | |
| 1437 @code{2}. | |
| 1438 @end defopt | |
| 1439 | |
| 444 | 1440 @deffn Command recenter &optional location window |
| 428 | 1441 @cindex centering point |
| 444 | 1442 This function scrolls @var{window} (which defaults to the selected |
| 1443 window) to put the text where point is located at a specified vertical | |
| 1444 position within the window. | |
| 428 | 1445 |
| 444 | 1446 If @var{location} is a nonnegative number, it puts the line containing |
| 1447 point @var{location} lines down from the top of the window. If @var{location} | |
| 428 | 1448 is a negative number, then it counts upward from the bottom of the |
| 1449 window, so that @minus{}1 stands for the last usable line in the window. | |
| 444 | 1450 If @var{location} is a non-@code{nil} list, then it stands for the line in |
| 428 | 1451 the middle of the window. |
| 1452 | |
| 444 | 1453 If @var{location} is @code{nil}, @code{recenter} puts the line containing |
| 428 | 1454 point in the middle of the window, then clears and redisplays the entire |
| 1455 selected frame. | |
| 1456 | |
| 444 | 1457 When @code{recenter} is called interactively, @var{location} is the raw |
| 428 | 1458 prefix argument. Thus, typing @kbd{C-u} as the prefix sets the |
| 444 | 1459 @var{location} to a non-@code{nil} list, while typing @kbd{C-u 4} sets |
| 1460 @var{location} to 4, which positions the current line four lines from the | |
| 428 | 1461 top. |
| 1462 | |
| 1463 With an argument of zero, @code{recenter} positions the current line at | |
| 1464 the top of the window. This action is so handy that some people make a | |
| 1465 separate key binding to do this. For example, | |
| 1466 | |
| 1467 @example | |
| 1468 @group | |
| 1469 (defun line-to-top-of-window () | |
| 1470 "Scroll current line to top of window. | |
| 1471 Replaces three keystroke sequence C-u 0 C-l." | |
| 444 | 1472 (interactive) |
| 428 | 1473 (recenter 0)) |
| 1474 | |
| 444 | 1475 (global-set-key [kp-multiply] 'line-to-top-of-window) |
| 428 | 1476 @end group |
| 1477 @end example | |
| 1478 @end deffn | |
| 1479 | |
| 1480 @node Horizontal Scrolling | |
| 1481 @section Horizontal Scrolling | |
| 1482 @cindex horizontal scrolling | |
| 1483 | |
| 1484 Because we read English first from top to bottom and second from left | |
| 1485 to right, horizontal scrolling is not like vertical scrolling. Vertical | |
| 1486 scrolling involves selection of a contiguous portion of text to display. | |
| 1487 Horizontal scrolling causes part of each line to go off screen. The | |
| 1488 amount of horizontal scrolling is therefore specified as a number of | |
| 1489 columns rather than as a position in the buffer. It has nothing to do | |
| 1490 with the display-start position returned by @code{window-start}. | |
| 1491 | |
| 1492 Usually, no horizontal scrolling is in effect; then the leftmost | |
| 1493 column is at the left edge of the window. In this state, scrolling to | |
| 1494 the right is meaningless, since there is no data to the left of the | |
| 1495 screen to be revealed by it; so this is not allowed. Scrolling to the | |
| 1496 left is allowed; it scrolls the first columns of text off the edge of | |
| 1497 the window and can reveal additional columns on the right that were | |
| 1498 truncated before. Once a window has a nonzero amount of leftward | |
| 1499 horizontal scrolling, you can scroll it back to the right, but only so | |
| 1500 far as to reduce the net horizontal scroll to zero. There is no limit | |
| 1501 to how far left you can scroll, but eventually all the text will | |
| 1502 disappear off the left edge. | |
| 1503 | |
| 444 | 1504 @deffn Command scroll-left &optional count |
| 428 | 1505 This function scrolls the selected window @var{count} columns to the |
| 1506 left (or to the right if @var{count} is negative). The return value is | |
| 1507 the total amount of leftward horizontal scrolling in effect after the | |
| 1508 change---just like the value returned by @code{window-hscroll} (below). | |
| 1509 @end deffn | |
| 1510 | |
| 444 | 1511 @deffn Command scroll-right &optional count |
| 428 | 1512 This function scrolls the selected window @var{count} columns to the |
| 1513 right (or to the left if @var{count} is negative). The return value is | |
| 1514 the total amount of leftward horizontal scrolling in effect after the | |
| 1515 change---just like the value returned by @code{window-hscroll} (below). | |
| 1516 | |
| 1517 Once you scroll a window as far right as it can go, back to its normal | |
| 1518 position where the total leftward scrolling is zero, attempts to scroll | |
| 1519 any farther right have no effect. | |
| 1520 @end deffn | |
| 1521 | |
| 1522 @defun window-hscroll &optional window | |
| 1523 This function returns the total leftward horizontal scrolling of | |
| 1524 @var{window}---the number of columns by which the text in @var{window} | |
| 1525 is scrolled left past the left margin. | |
| 1526 | |
| 1527 The value is never negative. It is zero when no horizontal scrolling | |
| 1528 has been done in @var{window} (which is usually the case). | |
| 1529 | |
| 1530 If @var{window} is @code{nil}, the selected window is used. | |
| 1531 | |
| 1532 @example | |
| 1533 @group | |
| 1534 (window-hscroll) | |
| 1535 @result{} 0 | |
| 1536 @end group | |
| 1537 @group | |
| 1538 (scroll-left 5) | |
| 1539 @result{} 5 | |
| 1540 @end group | |
| 1541 @group | |
| 1542 (window-hscroll) | |
| 1543 @result{} 5 | |
| 1544 @end group | |
| 1545 @end example | |
| 1546 @end defun | |
| 1547 | |
| 1548 @defun set-window-hscroll window columns | |
| 1549 This function sets the number of columns from the left margin that | |
| 1550 @var{window} is scrolled to the value of @var{columns}. The argument | |
| 1551 @var{columns} should be zero or positive; if not, it is taken as zero. | |
| 1552 | |
| 1553 The value returned is @var{columns}. | |
| 1554 | |
| 1555 @example | |
| 1556 @group | |
| 1557 (set-window-hscroll (selected-window) 10) | |
| 1558 @result{} 10 | |
| 1559 @end group | |
| 1560 @end example | |
| 1561 @end defun | |
| 1562 | |
| 1563 Here is how you can determine whether a given position @var{position} | |
| 1564 is off the screen due to horizontal scrolling: | |
| 1565 | |
| 1566 @example | |
| 1567 @group | |
| 1568 (defun hscroll-on-screen (window position) | |
| 444 | 1569 (save-excursion |
| 428 | 1570 (goto-char position) |
| 444 | 1571 (and |
| 428 | 1572 (>= (- (current-column) (window-hscroll window)) 0) |
| 1573 (< (- (current-column) (window-hscroll window)) | |
| 1574 (window-width window))))) | |
| 1575 @end group | |
| 1576 @end example | |
| 1577 @node Size of Window | |
| 1578 @section The Size of a Window | |
| 1579 @cindex window size | |
| 1580 @cindex size of window | |
| 1581 | |
| 1582 An Emacs window is rectangular, and its size information consists of | |
| 1583 the height (in lines or pixels) and the width (in character positions | |
| 1584 or pixels). The modeline is included in the height. The pixel | |
| 1585 width and height values include scrollbars and margins, while the | |
| 1586 line/character-position values do not. | |
| 1587 | |
| 1588 Note that the height in lines, and the width in characters, are | |
| 1589 determined by dividing the corresponding pixel value by the height or | |
| 1590 width of the default font in that window (if this is a variable-width | |
| 1591 font, the average width is used). The resulting values may or may not | |
| 1592 represent the actual number of lines in the window, or the actual number | |
| 1593 of character positions in any particular line, esp. if there are pixmaps | |
| 1594 or various different fonts in the window. | |
| 1595 | |
| 1596 The following functions return size information about a window: | |
| 1597 | |
| 1598 @defun window-height &optional window | |
| 1599 This function returns the number of lines in @var{window}, including | |
| 1600 its modeline but not including the horizontal scrollbar, if any (this | |
| 1601 is different from @code{window-pixel-height}). If @var{window} is | |
| 1602 @code{nil}, the function uses the selected window. | |
| 1603 | |
| 1604 @example | |
| 1605 @group | |
| 1606 (window-height) | |
| 1607 @result{} 40 | |
| 1608 @end group | |
| 1609 @group | |
| 1610 (split-window-vertically) | |
| 1611 @result{} #<window on "windows.texi" 0x679b> | |
| 1612 @end group | |
| 1613 @group | |
| 1614 (window-height) | |
| 1615 @result{} 20 | |
| 1616 @end group | |
| 1617 @end example | |
| 1618 @end defun | |
| 1619 | |
| 1620 @defun window-width &optional window | |
| 1621 This function returns the number of columns in @var{window}, not | |
| 1622 including any left margin, right margin, or vertical scrollbar (this is | |
| 1623 different from @code{window-pixel-width}). If @var{window} is | |
| 1624 @code{nil}, the function uses the selected window. | |
| 1625 | |
| 1626 @example | |
| 1627 @group | |
| 1628 (window-width) | |
| 1629 @result{} 80 | |
| 1630 @end group | |
| 1631 @group | |
| 1632 (window-height) | |
| 1633 @result{} 40 | |
| 1634 @end group | |
| 1635 @group | |
| 1636 (split-window-horizontally) | |
| 1637 @result{} #<window on "windows.texi" 0x7538> | |
| 1638 @end group | |
| 1639 @group | |
| 1640 (window-width) | |
| 1641 @result{} 39 | |
| 1642 @end group | |
| 1643 @end example | |
| 1644 @end defun | |
| 1645 | |
| 1646 Note that after splitting the window into two side-by-side windows, | |
| 1647 the width of each window is less the half the width of the original | |
| 1648 window because a vertical scrollbar appeared between the windows, | |
| 1649 occupying two columns worth of space. Also, the height shrunk by | |
| 1650 one because horizontal scrollbars appeared that weren't there | |
| 1651 before. (Horizontal scrollbars appear only when lines are | |
| 1652 truncated, not when they wrap. This is usually the case for | |
| 1653 horizontally split windows but not for full-frame windows. You | |
| 1654 can change this using the variables @code{truncate-lines} and | |
| 1655 @code{truncate-partial-width-windows}.) | |
| 1656 | |
| 1657 @defun window-pixel-height &optional window | |
| 1658 This function returns the height of @var{window} in pixels, including | |
| 1659 its modeline and horizontal scrollbar, if any. If @var{window} is | |
| 1660 @code{nil}, the function uses the selected window. | |
| 1661 | |
| 1662 @example | |
| 1663 @group | |
| 1664 (window-pixel-height) | |
| 1665 @result{} 600 | |
| 1666 @end group | |
| 1667 @group | |
| 1668 (split-window-vertically) | |
| 1669 @result{} #<window on "windows.texi" 0x68a6> | |
| 1670 @end group | |
| 1671 @group | |
| 1672 (window-pixel-height) | |
| 1673 @result{} 300 | |
| 1674 @end group | |
| 1675 @end example | |
| 1676 @end defun | |
| 1677 | |
| 1678 @defun window-pixel-width &optional window | |
| 1679 This function returns the width of @var{window} in pixels, including | |
| 1680 any left margin, right margin, or vertical scrollbar that may be | |
| 1681 displayed alongside it. If @var{window} is @code{nil}, the function | |
| 1682 uses the selected window. | |
| 1683 | |
| 1684 @example | |
| 1685 @group | |
| 1686 (window-pixel-width) | |
| 1687 @result{} 735 | |
| 1688 @end group | |
| 1689 @group | |
| 1690 (window-pixel-height) | |
| 1691 @result{} 600 | |
| 1692 @end group | |
| 1693 @group | |
| 1694 (split-window-horizontally) | |
| 1695 @result{} #<window on "windows.texi" 0x7538> | |
| 1696 @end group | |
| 1697 @group | |
| 1698 (window-pixel-width) | |
| 1699 @result{} 367 | |
| 1700 @end group | |
| 1701 @group | |
| 1702 (window-pixel-height) | |
| 1703 @result{} 600 | |
| 1704 @end group | |
| 1705 @end example | |
| 1706 @end defun | |
| 1707 | |
| 1708 @defun window-text-area-pixel-height &optional window | |
| 1709 This function returns the height in pixels of the text displaying | |
| 1710 portion of @var{window}, which defaults to the selected window. Unlike | |
| 1711 @code{window-pixel-height}, the space occupied by the modeline and | |
| 1712 horizontal scrollbar, if any, is not counted. | |
| 1713 @end defun | |
| 1714 | |
| 1715 @defun window-text-area-pixel-width &optional window | |
| 1716 This function returns the width in pixels of the text displaying | |
| 1717 portion of @var{window}, which defaults to the selected window. Unlike | |
| 1718 @code{window-pixel-width}, the space occupied by the vertical scrollbar | |
| 1719 and divider, if any, is not counted. | |
| 1720 @end defun | |
| 1721 | |
| 1722 @defun window-displayed-text-pixel-height &optional window noclipped | |
| 1723 This function returns the height in pixels of the text displayed in | |
| 1724 @var{window}, which defaults to the selected window. Unlike | |
| 1725 @code{window-text-area-pixel-height}, any blank space below the | |
| 444 | 1726 end of the buffer is not included. If optional argument @var{noclipped} |
| 428 | 1727 is non-@code{nil}, any space occupied by clipped lines will not be |
| 1728 included. | |
| 1729 @end defun | |
| 1730 | |
| 1731 @node Position of Window | |
| 1732 @section The Position of a Window | |
| 1733 @cindex window position | |
| 1734 @cindex position of window | |
| 1735 | |
| 1736 XEmacs provides functions to determine the absolute location of windows | |
| 1737 within a frame, and the relative location of a window in comparison to | |
| 1738 other windows in the same frame. | |
| 1739 | |
| 1740 @defun window-pixel-edges &optional window | |
| 1741 This function returns a list of the pixel edge coordinates of | |
| 1742 @var{window}. If @var{window} is @code{nil}, the selected window is | |
| 1743 used. | |
| 1744 | |
| 1745 The order of the list is @code{(@var{left} @var{top} @var{right} | |
| 1746 @var{bottom})}, all elements relative to 0, 0 at the top left corner of | |
| 444 | 1747 @var{window}'s frame. The element @var{right} of the value is one more |
| 1748 than the rightmost pixel used by @var{window} (including any left | |
| 1749 margin, right margin, or vertical scrollbar displayed alongside it), and | |
| 428 | 1750 @var{bottom} is one more than the bottommost pixel used by @var{window} |
| 444 | 1751 (including any modeline or horizontal scrollbar displayed above or below |
| 1752 it). The frame area does not include any frame menubars, toolbars, or | |
| 1753 gutters that may be displayed; thus, for example, if there is only one | |
| 1754 window on the frame, the values for @var{left} and @var{top} will always | |
| 1755 be 0. | |
| 428 | 1756 |
| 1757 If @var{window} is at the upper left corner of its frame, @var{right} | |
| 1758 and @var{bottom} are the same as the values returned by | |
| 1759 @code{(window-pixel-width)} and @code{(window-pixel-height)} | |
| 444 | 1760 respectively, and @var{left} and @var{top} are zero. |
| 428 | 1761 @end defun |
| 1762 | |
| 1763 There is no longer a function @code{window-edges} because it does not | |
| 1764 make sense in a world with variable-width and variable-height lines, | |
| 1765 as are allowed in XEmacs. | |
| 1766 | |
| 1767 @defun window-highest-p window | |
| 1768 This function returns non-@code{nil} if @var{window} is along the | |
| 1769 top of its frame. | |
| 1770 @end defun | |
| 1771 | |
| 1772 @defun window-lowest-p window | |
| 1773 This function returns non-@code{nil} if @var{window} is along the | |
| 1774 bottom of its frame. | |
| 1775 @end defun | |
| 1776 | |
| 1777 @defun window-text-area-pixel-edges &optional window | |
| 1778 This function allows one to determine the location of the | |
| 1779 text-displaying portion of @var{window}, which defaults to the selected | |
| 1780 window, with respect to the top left corner of the window. It returns | |
| 1781 a list of integer pixel positions @code{(left top right bottom)}, all | |
| 1782 relative to @code{(0,0)} at the top left corner of the window. | |
| 1783 @end defun | |
| 1784 | |
| 1785 @node Resizing Windows | |
| 1786 @section Changing the Size of a Window | |
| 1787 @cindex window resizing | |
| 1788 @cindex changing window size | |
| 1789 @cindex window size, changing | |
| 1790 | |
| 1791 The window size functions fall into two classes: high-level commands | |
| 1792 that change the size of windows and low-level functions that access | |
| 1793 window size. XEmacs does not permit overlapping windows or gaps between | |
| 1794 windows, so resizing one window affects other windows. | |
| 1795 | |
| 444 | 1796 @deffn Command enlarge-window count &optional horizontal window |
| 1797 This function makes the selected window @var{count} lines taller, | |
| 428 | 1798 stealing lines from neighboring windows. It takes the lines from one |
| 1799 window at a time until that window is used up, then takes from another. | |
| 1800 If a window from which lines are stolen shrinks below | |
| 1801 @code{window-min-height} lines, that window disappears. | |
| 1802 | |
| 1803 If @var{horizontal} is non-@code{nil}, this function makes | |
| 444 | 1804 @var{window} wider by @var{count} columns, stealing columns instead of |
| 428 | 1805 lines. If a window from which columns are stolen shrinks below |
| 1806 @code{window-min-width} columns, that window disappears. | |
| 1807 | |
| 1808 If the requested size would exceed that of the window's frame, then the | |
| 1809 function makes the window occupy the entire height (or width) of the | |
| 1810 frame. | |
| 1811 | |
| 444 | 1812 If @var{count} is negative, this function shrinks the window by |
| 1813 @minus{}@var{count} lines or columns. If that makes the window smaller | |
| 428 | 1814 than the minimum size (@code{window-min-height} and |
| 1815 @code{window-min-width}), @code{enlarge-window} deletes the window. | |
| 1816 | |
| 1817 If @var{window} is non-@code{nil}, it specifies a window to change | |
| 1818 instead of the selected window. | |
| 1819 | |
| 444 | 1820 @code{enlarge-window} returns @code{nil}. |
| 428 | 1821 @end deffn |
| 1822 | |
| 1823 @deffn Command enlarge-window-horizontally columns | |
| 1824 This function makes the selected window @var{columns} wider. | |
| 1825 It could be defined as follows: | |
| 1826 | |
| 1827 @example | |
| 1828 @group | |
| 1829 (defun enlarge-window-horizontally (columns) | |
| 1830 (enlarge-window columns t)) | |
| 1831 @end group | |
| 1832 @end example | |
| 1833 @end deffn | |
| 1834 | |
| 1835 @deffn Command enlarge-window-pixels count &optional side window | |
| 444 | 1836 This function makes the selected window @var{count} pixels larger. |
| 1837 When called from Lisp, optional second argument @var{side} | |
| 1838 non-@code{nil} means to grow sideways @var{count} pixels, and optional | |
| 1839 third argument @var{window} specifies the window to change instead of | |
| 1840 the selected window. | |
| 428 | 1841 @end deffn |
| 1842 | |
| 444 | 1843 @deffn Command shrink-window count &optional horizontal window |
| 428 | 1844 This function is like @code{enlarge-window} but negates the argument |
| 444 | 1845 @var{count}, making the selected window smaller by giving lines (or |
| 428 | 1846 columns) to the other windows. If the window shrinks below |
| 1847 @code{window-min-height} or @code{window-min-width}, then it disappears. | |
| 1848 | |
| 444 | 1849 If @var{count} is negative, the window is enlarged by @minus{}@var{count} |
| 428 | 1850 lines or columns. |
| 1851 | |
| 1852 If @var{window} is non-@code{nil}, it specifies a window to change | |
| 1853 instead of the selected window. | |
| 1854 @end deffn | |
| 1855 | |
| 1856 @deffn Command shrink-window-horizontally columns | |
| 1857 This function makes the selected window @var{columns} narrower. | |
| 1858 It could be defined as follows: | |
| 1859 | |
| 1860 @example | |
| 1861 @group | |
| 1862 (defun shrink-window-horizontally (columns) | |
| 1863 (shrink-window columns t)) | |
| 1864 @end group | |
| 1865 @end example | |
| 1866 @end deffn | |
| 1867 | |
| 1868 @deffn Command shrink-window-pixels count &optional side window | |
| 1869 This function makes the selected window @var{count} pixels smaller. | |
| 1870 When called from Lisp, optional second argument @var{side} | |
| 1871 non-@code{nil} means to shrink sideways @var{count} pixels, and optional | |
| 1872 third argument @var{window} specifies the window to change instead of | |
| 1873 the selected window. | |
| 1874 @end deffn | |
| 1875 | |
| 1876 @cindex minimum window size | |
| 1877 The following two variables constrain the window-size-changing | |
| 1878 functions to a minimum height and width. | |
| 1879 | |
| 1880 @defopt window-min-height | |
| 1881 The value of this variable determines how short a window may become | |
| 1882 before it is automatically deleted. Making a window smaller than | |
| 1883 @code{window-min-height} automatically deletes it, and no window may be | |
| 1884 created shorter than this. The absolute minimum height is two (allowing | |
| 1885 one line for the mode line, and one line for the buffer display). | |
| 1886 Actions that change window sizes reset this variable to two if it is | |
| 1887 less than two. The default value is 4. | |
| 1888 @end defopt | |
| 1889 | |
| 1890 @defopt window-min-width | |
| 1891 The value of this variable determines how narrow a window may become | |
| 1892 before it automatically deleted. Making a window smaller than | |
| 1893 @code{window-min-width} automatically deletes it, and no window may be | |
| 1894 created narrower than this. The absolute minimum width is one; any | |
| 1895 value below that is ignored. The default value is 10. | |
| 1896 @end defopt | |
| 1897 | |
| 1898 @c This is not yet implemented. Why is it "documented"? | |
| 1899 @defvar window-size-change-functions | |
| 1900 This variable holds a list of functions to be called if the size of any | |
| 1901 window changes for any reason. The functions are called just once per | |
| 1902 redisplay, and just once for each frame on which size changes have | |
| 1903 occurred. | |
| 1904 | |
| 1905 Each function receives the frame as its sole argument. There is no | |
| 1906 direct way to find out which windows changed size, or precisely how; | |
| 1907 however, if your size-change function keeps track, after each change, of | |
| 1908 the windows that interest you, you can figure out what has changed by | |
| 1909 comparing the old size data with the new. | |
| 1910 | |
| 1911 Creating or deleting windows counts as a size change, and therefore | |
| 1912 causes these functions to be called. Changing the frame size also | |
| 1913 counts, because it changes the sizes of the existing windows. | |
| 1914 | |
| 1915 It is not a good idea to use @code{save-window-excursion} in these | |
| 1916 functions, because that always counts as a size change, and it would | |
| 1917 cause these functions to be called over and over. In most cases, | |
| 1918 @code{save-selected-window} is what you need here. | |
| 1919 @end defvar | |
| 1920 | |
| 1921 @node Window Configurations | |
| 1922 @section Window Configurations | |
| 1923 @cindex window configurations | |
| 1924 @cindex saving window information | |
| 1925 | |
| 1926 A @dfn{window configuration} records the entire layout of a | |
| 1927 frame---all windows, their sizes, which buffers they contain, what part | |
| 1928 of each buffer is displayed, and the values of point and the mark. You | |
| 1929 can bring back an entire previous layout by restoring a window | |
| 1930 configuration previously saved. | |
| 1931 | |
| 1932 If you want to record all frames instead of just one, use a frame | |
| 1933 configuration instead of a window configuration. @xref{Frame | |
| 1934 Configurations}. | |
| 1935 | |
| 444 | 1936 @defun current-window-configuration &optional frame |
| 625 | 1937 This function returns a new object representing the current window |
| 1938 configuration of @var{frame}, namely the number of windows, their sizes | |
| 1939 and current buffers, which window is the selected window, and for each | |
| 1940 window the displayed buffer, the display-start position, and the | |
| 444 | 1941 positions of point and the mark. An exception is made for point in the |
| 1942 current buffer, whose value is not saved. | |
| 1943 | |
| 1944 @var{frame} defaults to the selected frame. | |
| 428 | 1945 @end defun |
| 1946 | |
| 1947 @defun set-window-configuration configuration | |
| 1948 This function restores the configuration of XEmacs's windows and | |
| 1949 buffers to the state specified by @var{configuration}. The argument | |
| 1950 @var{configuration} must be a value that was previously returned by | |
| 1951 @code{current-window-configuration}. | |
| 1952 | |
| 1953 This function always counts as a window size change and triggers | |
| 1954 execution of the @code{window-size-change-functions}. (It doesn't know | |
| 1955 how to tell whether the new configuration actually differs from the old | |
| 1956 one.) | |
| 1957 | |
| 1958 Here is a way of using this function to get the same effect | |
| 1959 as @code{save-window-excursion}: | |
| 1960 | |
| 1961 @example | |
| 1962 @group | |
| 1963 (let ((config (current-window-configuration))) | |
| 1964 (unwind-protect | |
| 1965 (progn (split-window-vertically nil) | |
| 1966 @dots{}) | |
| 1967 (set-window-configuration config))) | |
| 1968 @end group | |
| 1969 @end example | |
| 1970 @end defun | |
| 1971 | |
| 1972 @defspec save-window-excursion forms@dots{} | |
|
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|
1973 This macro records the window configuration, executes @var{forms} |
| 428 | 1974 in sequence, then restores the earlier window configuration. The window |
| 1975 configuration includes the value of point and the portion of the buffer | |
| 1976 that is visible. It also includes the choice of selected window. | |
| 1977 However, it does not include the value of point in the current buffer; | |
| 1978 use @code{save-excursion} if you wish to preserve that. | |
| 1979 | |
| 1980 Don't use this construct when @code{save-selected-window} is all you need. | |
| 1981 | |
| 1982 Exit from @code{save-window-excursion} always triggers execution of the | |
| 1983 @code{window-size-change-functions}. (It doesn't know how to tell | |
| 1984 whether the restored configuration actually differs from the one in | |
| 1985 effect at the end of the @var{forms}.) | |
| 1986 | |
| 1987 The return value is the value of the final form in @var{forms}. | |
| 1988 For example: | |
| 1989 | |
| 1990 @example | |
| 1991 @group | |
| 1992 (split-window) | |
| 1993 @result{} #<window 25 on control.texi> | |
| 1994 @end group | |
| 1995 @group | |
| 1996 (setq w (selected-window)) | |
| 1997 @result{} #<window 19 on control.texi> | |
| 1998 @end group | |
| 1999 @group | |
| 2000 (save-window-excursion | |
| 2001 (delete-other-windows w) | |
| 2002 (switch-to-buffer "foo") | |
| 2003 'do-something) | |
| 2004 @result{} do-something | |
| 2005 ;; @r{The frame is now split again.} | |
| 2006 @end group | |
| 2007 @end example | |
| 2008 @end defspec | |
| 2009 | |
| 2010 @defun window-configuration-p object | |
| 2011 This function returns @code{t} if @var{object} is a window configuration. | |
| 2012 @end defun | |
| 2013 | |
| 2014 Primitives to look inside of window configurations would make sense, | |
| 2015 but none are implemented. It is not clear they are useful enough to be | |
| 2016 worth implementing. |