This is Info file ../../info/lispref.info, produced by Makeinfo-1.63
from the input file lispref.texi.

   Edition History:

   GNU Emacs Lisp Reference Manual Second Edition (v2.01), May 1993 GNU
Emacs Lisp Reference Manual Further Revised (v2.02), August 1993 Lucid
Emacs Lisp Reference Manual (for 19.10) First Edition, March 1994
XEmacs Lisp Programmer's Manual (for 19.12) Second Edition, April 1995
GNU Emacs Lisp Reference Manual v2.4, June 1995 XEmacs Lisp
Programmer's Manual (for 19.13) Third Edition, July 1995 XEmacs Lisp
Reference Manual (for 19.14 and 20.0) v3.1, March 1996

   Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995 Free Software
Foundation, Inc.  Copyright (C) 1994, 1995 Sun Microsystems, Inc.
Copyright (C) 1995, 1996 Ben Wing.

   Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.

   Permission is granted to copy and distribute modified versions of
this manual under the conditions for verbatim copying, provided that the
entire resulting derived work is distributed under the terms of a
permission notice identical to this one.

   Permission is granted to copy and distribute translations of this
manual into another language, under the above conditions for modified
versions, except that this permission notice may be stated in a
translation approved by the Foundation.

   Permission is granted to copy and distribute modified versions of
this manual under the conditions for verbatim copying, provided also
that the section entitled "GNU General Public License" is included
exactly as in the original, and provided that the entire resulting
derived work is distributed under the terms of a permission notice
identical to this one.

   Permission is granted to copy and distribute translations of this
manual into another language, under the above conditions for modified
versions, except that the section entitled "GNU General Public License"
may be included in a translation approved by the Free Software
Foundation instead of in the original English.


File: lispref.info,  Node: Window Point,  Next: Window Start,  Prev: Choosing Window,  Up: Windows

Windows and Point
=================

   Each window has its own value of point, independent of the value of
point in other windows displaying the same buffer.  This makes it useful
to have multiple windows showing one buffer.

   * The window point is established when a window is first created; it
     is initialized from the buffer's point, or from the window point
     of another window opened on the buffer if such a window exists.

   * Selecting a window sets the value of point in its buffer to the
     window's value of point.  Conversely, deselecting a window sets
     the window's value of point from that of the buffer.  Thus, when
     you switch between windows that display a given buffer, the point
     value for the selected window is in effect in the buffer, while
     the point values for the other windows are stored in those windows.

   * As long as the selected window displays the current buffer, the
     window's point and the buffer's point always move together; they
     remain equal.

   * *Note Positions::, for more details on buffer positions.

   As far as the user is concerned, point is where the cursor is, and
when the user switches to another buffer, the cursor jumps to the
position of point in that buffer.

 - Function: window-point WINDOW
     This function returns the current position of point in WINDOW.
     For a nonselected window, this is the value point would have (in
     that window's buffer) if that window were selected.

     When WINDOW is the selected window and its buffer is also the
     current buffer, the value returned is the same as point in that
     buffer.

     Strictly speaking, it would be more correct to return the
     "top-level" value of point, outside of any `save-excursion' forms.
     But that value is hard to find.

 - Function: set-window-point WINDOW POSITION
     This function positions point in WINDOW at position POSITION in
     WINDOW's buffer.


File: lispref.info,  Node: Window Start,  Next: Vertical Scrolling,  Prev: Window Point,  Up: Windows

The Window Start Position
=========================

   Each window contains a marker used to keep track of a buffer position
that specifies where in the buffer display should start.  This position
is called the "display-start" position of the window (or just the
"start").  The character after this position is the one that appears at
the upper left corner of the window.  It is usually, but not
inevitably, at the beginning of a text line.

 - Function: window-start &optional WINDOW
     This function returns the display-start position of window WINDOW.
     If WINDOW is `nil', the selected window is used.  For example,

          (window-start)
               => 7058

     When you create a window, or display a different buffer in it, the
     display-start position is set to a display-start position recently
     used for the same buffer, or 1 if the buffer doesn't have any.

     For a realistic example, see the description of `count-lines' in
     *Note Text Lines::.

 - Function: window-end &optional WINDOW
     This function returns the position of the end of the display in
     window WINDOW.  If WINDOW is `nil', the selected window is used.

     Simply changing the buffer text or moving point does not update the
     value that `window-end' returns.  The value is updated only when
     Emacs redisplays and redisplay actually finishes.

     If the last redisplay of WINDOW was preempted, and did not finish,
     Emacs does not know the position of the end of display in that
     window.  In that case, this function returns a value that is not
     correct.  In a future version, `window-end' will return `nil' in
     that case.

 - Function: set-window-start WINDOW POSITION &optional NOFORCE
     This function sets the display-start position of WINDOW to
     POSITION in WINDOW's buffer.  It returns POSITION.

     The display routines insist that the position of point be visible
     when a buffer is displayed.  Normally, they change the
     display-start position (that is, scroll the window) whenever
     necessary to make point visible.  However, if you specify the
     start position with this function using `nil' for NOFORCE, it
     means you want display to start at POSITION even if that would put
     the location of point off the screen.  If this does place point
     off screen, the display routines move point to the left margin on
     the middle line in the window.

     For example, if point is 1 and you set the start of the window
     to 2, then point would be "above" the top of the window.  The
     display routines will automatically move point if it is still 1
     when redisplay occurs.  Here is an example:

          ;; Here is what `foo' looks like before executing
          ;;   the `set-window-start' expression.
          
          ---------- Buffer: foo ----------
          -!-This is the contents of buffer foo.
          2
          3
          4
          5
          6
          ---------- Buffer: foo ----------
          
          (set-window-start
           (selected-window)
           (1+ (window-start)))
          => 2
          
          ;; Here is what `foo' looks like after executing
          ;;   the `set-window-start' expression.
          ---------- Buffer: foo ----------
          his is the contents of buffer foo.
          2
          3
          -!-4
          5
          6
          ---------- Buffer: foo ----------

     If NOFORCE is non-`nil', and POSITION would place point off screen
     at the next redisplay, then redisplay computes a new window-start
     position that works well with point, and thus POSITION is not used.

 - Function: pos-visible-in-window-p &optional POSITION WINDOW
     This function returns `t' if POSITION is within the range of text
     currently visible on the screen in WINDOW.  It returns `nil' if
     POSITION is scrolled vertically out of view.  The argument
     POSITION defaults to the current position of point; WINDOW, to the
     selected window.  Here is an example:

          (or (pos-visible-in-window-p
               (point) (selected-window))
              (recenter 0))

     The `pos-visible-in-window-p' function considers only vertical
     scrolling.  If POSITION is out of view only because WINDOW has
     been scrolled horizontally, `pos-visible-in-window-p' returns `t'.
     *Note Horizontal Scrolling::.


File: lispref.info,  Node: Vertical Scrolling,  Next: Horizontal Scrolling,  Prev: Window Start,  Up: Windows

Vertical Scrolling
==================

   Vertical scrolling means moving the text up or down in a window.  It
works by changing the value of the window's display-start location.  It
may also change the value of `window-point' to keep it on the screen.

   In the commands `scroll-up' and `scroll-down', the directions "up"
and "down" refer to the motion of the text in the buffer at which you
are looking through the window.  Imagine that the text is written on a
long roll of paper and that the scrolling commands move the paper up
and down.  Thus, if you are looking at text in the middle of a buffer
and repeatedly call `scroll-down', you will eventually see the
beginning of the buffer.

   Some people have urged that the opposite convention be used: they
imagine that the window moves over text that remains in place.  Then
"down" commands would take you to the end of the buffer.  This view is
more consistent with the actual relationship between windows and the
text in the buffer, but it is less like what the user sees.  The
position of a window on the terminal does not move, and short scrolling
commands clearly move the text up or down on the screen.  We have chosen
names that fit the user's point of view.

   The scrolling functions (aside from `scroll-other-window') have
unpredictable results if the current buffer is different from the buffer
that is displayed in the selected window.  *Note Current Buffer::.

 - Command: scroll-up &optional COUNT
     This function scrolls the text in the selected window upward COUNT
     lines.  If COUNT is negative, scrolling is actually downward.

     If COUNT is `nil' (or omitted), then the length of scroll is
     `next-screen-context-lines' lines less than the usable height of
     the window (not counting its modeline).

     `scroll-up' returns `nil'.

 - Command: scroll-down &optional COUNT
     This function scrolls the text in the selected window downward
     COUNT lines.  If COUNT is negative, scrolling is actually upward.

     If COUNT is omitted or `nil', then the length of the scroll is
     `next-screen-context-lines' lines less than the usable height of
     the window (not counting its mode line).

     `scroll-down' returns `nil'.

 - Command: scroll-other-window &optional COUNT
     This function scrolls the text in another window upward COUNT
     lines.  Negative values of COUNT, or `nil', are handled as in
     `scroll-up'.

     You can specify a buffer to scroll with the variable
     `other-window-scroll-buffer'.  When the selected window is the
     minibuffer, the next window is normally the one at the top left
     corner.  You can specify a different window to scroll with the
     variable `minibuffer-scroll-window'.  This variable has no effect
     when any other window is selected.  *Note Minibuffer Misc::.

     When the minibuffer is active, it is the next window if the
     selected window is the one at the bottom right corner.  In this
     case, `scroll-other-window' attempts to scroll the minibuffer.  If
     the minibuffer contains just one line, it has nowhere to scroll
     to, so the line reappears after the echo area momentarily displays
     the message "Beginning of buffer".

 - Variable: other-window-scroll-buffer
     If this variable is non-`nil', it tells `scroll-other-window'
     which buffer to scroll.

 - User Option: scroll-step
     This variable controls how scrolling is done automatically when
     point moves off the screen.  If the value is zero, then redisplay
     scrolls the text to center point vertically in the window.  If the
     value is a positive integer N, then redisplay brings point back on
     screen by scrolling N lines in either direction, if possible;
     otherwise, it centers point.  The default value is zero.

 - User Option: next-screen-context-lines
     The value of this variable is the number of lines of continuity to
     retain when scrolling by full screens.  For example, `scroll-up'
     with an argument of `nil' scrolls so that this many lines at the
     bottom of the window appear instead at the top.  The default value
     is `2'.

 - Command: recenter &optional COUNT
     This function scrolls the selected window to put the text where
     point is located at a specified vertical position within the
     window.

     If COUNT is a nonnegative number, it puts the line containing
     point COUNT lines down from the top of the window.  If COUNT is a
     negative number, then it counts upward from the bottom of the
     window, so that -1 stands for the last usable line in the window.
     If COUNT is a non-`nil' list, then it stands for the line in the
     middle of the window.

     If COUNT is `nil', `recenter' puts the line containing point in
     the middle of the window, then clears and redisplays the entire
     selected frame.

     When `recenter' is called interactively, COUNT is the raw prefix
     argument.  Thus, typing `C-u' as the prefix sets the COUNT to a
     non-`nil' list, while typing `C-u 4' sets COUNT to 4, which
     positions the current line four lines from the top.

     With an argument of zero, `recenter' positions the current line at
     the top of the window.  This action is so handy that some people
     make a separate key binding to do this.  For example,

          (defun line-to-top-of-window ()
            "Scroll current line to top of window.
          Replaces three keystroke sequence C-u 0 C-l."
            (interactive)
            (recenter 0))
          
          (global-set-key [kp-multiply] 'line-to-top-of-window)


File: lispref.info,  Node: Horizontal Scrolling,  Next: Size of Window,  Prev: Vertical Scrolling,  Up: Windows

Horizontal Scrolling
====================

   Because we read English first from top to bottom and second from left
to right, horizontal scrolling is not like vertical scrolling.  Vertical
scrolling involves selection of a contiguous portion of text to display.
Horizontal scrolling causes part of each line to go off screen.  The
amount of horizontal scrolling is therefore specified as a number of
columns rather than as a position in the buffer.  It has nothing to do
with the display-start position returned by `window-start'.

   Usually, no horizontal scrolling is in effect; then the leftmost
column is at the left edge of the window.  In this state, scrolling to
the right is meaningless, since there is no data to the left of the
screen to be revealed by it; so this is not allowed.  Scrolling to the
left is allowed; it scrolls the first columns of text off the edge of
the window and can reveal additional columns on the right that were
truncated before.  Once a window has a nonzero amount of leftward
horizontal scrolling, you can scroll it back to the right, but only so
far as to reduce the net horizontal scroll to zero.  There is no limit
to how far left you can scroll, but eventually all the text will
disappear off the left edge.

 - Command: scroll-left COUNT
     This function scrolls the selected window COUNT columns to the
     left (or to the right if COUNT is negative).  The return value is
     the total amount of leftward horizontal scrolling in effect after
     the change--just like the value returned by `window-hscroll'
     (below).

 - Command: scroll-right COUNT
     This function scrolls the selected window COUNT columns to the
     right (or to the left if COUNT is negative).  The return value is
     the total amount of leftward horizontal scrolling in effect after
     the change--just like the value returned by `window-hscroll'
     (below).

     Once you scroll a window as far right as it can go, back to its
     normal position where the total leftward scrolling is zero,
     attempts to scroll any farther right have no effect.

 - Function: window-hscroll &optional WINDOW
     This function returns the total leftward horizontal scrolling of
     WINDOW--the number of columns by which the text in WINDOW is
     scrolled left past the left margin.

     The value is never negative.  It is zero when no horizontal
     scrolling has been done in WINDOW (which is usually the case).

     If WINDOW is `nil', the selected window is used.

          (window-hscroll)
               => 0
          (scroll-left 5)
               => 5
          (window-hscroll)
               => 5

 - Function: set-window-hscroll WINDOW COLUMNS
     This function sets the number of columns from the left margin that
     WINDOW is scrolled to the value of COLUMNS.  The argument COLUMNS
     should be zero or positive; if not, it is taken as zero.

     The value returned is COLUMNS.

          (set-window-hscroll (selected-window) 10)
               => 10

   Here is how you can determine whether a given position POSITION is
off the screen due to horizontal scrolling:

     (defun hscroll-on-screen (window position)
       (save-excursion
         (goto-char position)
         (and
          (>= (- (current-column) (window-hscroll window)) 0)
          (< (- (current-column) (window-hscroll window))
             (window-width window)))))


File: lispref.info,  Node: Size of Window,  Next: Position of Window,  Prev: Horizontal Scrolling,  Up: Windows

The Size of a Window
====================

   An Emacs window is rectangular, and its size information consists of
the height (in lines or pixels) and the width (in character positions
or pixels).  The modeline is included in the height.  The pixel width
and height values include scrollbars and margins, while the
line/character-position values do not.

   Note that the height in lines, and the width in characters, are
determined by dividing the corresponding pixel value by the height or
width of the default font in that window (if this is a variable-width
font, the average width is used).  The resulting values may or may not
represent the actual number of lines in the window, or the actual number
of character positions in any particular line, esp. if there are pixmaps
or various different fonts in the window.

   The following functions return size information about a window:

 - Function: window-height &optional WINDOW
     This function returns the number of lines in WINDOW, including its
     modeline but not including the horizontal scrollbar, if any (this
     is different from `window-pixel-height').  If WINDOW is `nil', the
     function uses the selected window.

          (window-height)
               => 40
          (split-window-vertically)
               => #<window on "windows.texi" 0x679b>
          (window-height)
               => 20

 - Function: window-width &optional WINDOW
     This function returns the number of columns in WINDOW, not
     including any left margin, right margin, or vertical scrollbar
     (this is different from `window-pixel-width').  If WINDOW is
     `nil', the function uses the selected window.

          (window-width)
               => 80
          (window-height)
               => 40
          (split-window-horizontally)
               => #<window on "windows.texi" 0x7538>
          (window-width)
               => 39

   Note that after splitting the window into two side-by-side windows,
the width of each window is less the half the width of the original
window because a vertical scrollbar appeared between the windows,
occupying two columns worth of space.  Also, the height shrunk by one
because horizontal scrollbars appeared that weren't there before.
(Horizontal scrollbars appear only when lines are truncated, not when
they wrap.  This is usually the case for horizontally split windows but
not for full-frame windows.  You can change this using the variables
`truncate-lines' and `truncate-partial-width-windows'.)

 - Function: window-pixel-height &optional WINDOW
     This function returns the height of WINDOW in pixels, including
     its modeline and horizontal scrollbar, if any.  If WINDOW is
     `nil', the function uses the selected window.

          (window-pixel-height)
               => 600
          (split-window-vertically)
               => #<window on "windows.texi" 0x68a6>
          (window-pixel-height)
               => 300

 - Function: window-pixel-width &optional WINDOW
     This function returns the width of WINDOW in pixels, including any
     left margin, right margin, or vertical scrollbar that may be
     displayed alongside it.  If WINDOW is `nil', the function uses the
     selected window.

          (window-pixel-width)
               => 735
          (window-pixel-height)
               => 600
          (split-window-horizontally)
               => #<window on "windows.texi" 0x7538>
          (window-pixel-width)
               => 367
          (window-pixel-height)
               => 600


File: lispref.info,  Node: Position of Window,  Next: Resizing Windows,  Prev: Size of Window,  Up: Windows

The Position of a Window
========================

   XEmacs provides functions to determine the absolute location of
windows within a frame, and the relative location of a window in
comparison to other windows in the same frame.

 - Function: window-pixel-edges &optional WINDOW
     This function returns a list of the pixel edge coordinates of
     WINDOW.  If WINDOW is `nil', the selected window is used.

     The order of the list is `(LEFT TOP RIGHT BOTTOM)', all elements
     relative to 0, 0 at the top left corner of the frame.  The element
     RIGHT of the value is one more than the rightmost pixel used by
     WINDOW (including any left margin, right margin, or vertical
     scrollbar displayed alongside it), and BOTTOM is one more than the
     bottommost pixel used by WINDOW (including any modeline or
     horizontal scrollbar displayed above or below it).  The frame area
     does not include any frame menubars or toolbars that may be
     displayed; thus, for example, if there is only one window on the
     frame, the values for LEFT and TOP will always be 0.

     If WINDOW is at the upper left corner of its frame, RIGHT and
     BOTTOM are the same as the values returned by
     `(window-pixel-width)' and `(window-pixel-height)' respectively,
     and TOP and BOTTOM are zero.

   There is no longer a function `window-edges' because it does not
make sense in a world with variable-width and variable-height lines, as
are allowed in XEmacs.

 - Function: window-highest-p WINDOW
     This function returns non-`nil' if WINDOW is along the top of its
     frame.

 - Function: window-lowest-p WINDOW
     This function returns non-`nil' if WINDOW is along the bottom of
     its frame.


File: lispref.info,  Node: Resizing Windows,  Next: Window Configurations,  Prev: Position of Window,  Up: Windows

Changing the Size of a Window
=============================

   The window size functions fall into two classes: high-level commands
that change the size of windows and low-level functions that access
window size.  XEmacs does not permit overlapping windows or gaps between
windows, so resizing one window affects other windows.

 - Command: enlarge-window SIZE &optional HORIZONTAL
     This function makes the selected window SIZE lines taller,
     stealing lines from neighboring windows.  It takes the lines from
     one window at a time until that window is used up, then takes from
     another.  If a window from which lines are stolen shrinks below
     `window-min-height' lines, that window disappears.

     If HORIZONTAL is non-`nil', this function makes WINDOW wider by
     SIZE columns, stealing columns instead of lines.  If a window from
     which columns are stolen shrinks below `window-min-width' columns,
     that window disappears.

     If the requested size would exceed that of the window's frame,
     then the function makes the window occupy the entire height (or
     width) of the frame.

     If SIZE is negative, this function shrinks the window by -SIZE
     lines or columns.  If that makes the window smaller than the
     minimum size (`window-min-height' and `window-min-width'),
     `enlarge-window' deletes the window.

     `enlarge-window' returns `nil'.

 - Command: enlarge-window-horizontally COLUMNS
     This function makes the selected window COLUMNS wider.  It could
     be defined as follows:

          (defun enlarge-window-horizontally (columns)
            (enlarge-window columns t))

 - Command: shrink-window SIZE &optional HORIZONTAL
     This function is like `enlarge-window' but negates the argument
     SIZE, making the selected window smaller by giving lines (or
     columns) to the other windows.  If the window shrinks below
     `window-min-height' or `window-min-width', then it disappears.

     If SIZE is negative, the window is enlarged by -SIZE lines or
     columns.

 - Command: shrink-window-horizontally COLUMNS
     This function makes the selected window COLUMNS narrower.  It
     could be defined as follows:

          (defun shrink-window-horizontally (columns)
            (shrink-window columns t))

   The following two variables constrain the window-size-changing
functions to a minimum height and width.

 - User Option: window-min-height
     The value of this variable determines how short a window may become
     before it is automatically deleted.  Making a window smaller than
     `window-min-height' automatically deletes it, and no window may be
     created shorter than this.  The absolute minimum height is two
     (allowing one line for the mode line, and one line for the buffer
     display).  Actions that change window sizes reset this variable to
     two if it is less than two.  The default value is 4.

 - User Option: window-min-width
     The value of this variable determines how narrow a window may
     become before it automatically deleted.  Making a window smaller
     than `window-min-width' automatically deletes it, and no window
     may be created narrower than this.  The absolute minimum width is
     one; any value below that is ignored.  The default value is 10.

 - Variable: window-size-change-functions
     This variable holds a list of functions to be called if the size
     of any window changes for any reason.  The functions are called
     just once per redisplay, and just once for each frame on which
     size changes have occurred.

     Each function receives the frame as its sole argument.  There is no
     direct way to find out which windows changed size, or precisely
     how; however, if your size-change function keeps track, after each
     change, of the windows that interest you, you can figure out what
     has changed by comparing the old size data with the new.

     Creating or deleting windows counts as a size change, and therefore
     causes these functions to be called.  Changing the frame size also
     counts, because it changes the sizes of the existing windows.

     It is not a good idea to use `save-window-excursion' in these
     functions, because that always counts as a size change, and it
     would cause these functions to be called over and over.  In most
     cases, `save-selected-window' is what you need here.


File: lispref.info,  Node: Window Configurations,  Prev: Resizing Windows,  Up: Windows

Window Configurations
=====================

   A "window configuration" records the entire layout of a frame--all
windows, their sizes, which buffers they contain, what part of each
buffer is displayed, and the values of point and the mark.  You can
bring back an entire previous layout by restoring a window
configuration previously saved.

   If you want to record all frames instead of just one, use a frame
configuration instead of a window configuration.  *Note Frame
Configurations::.

 - Function: current-window-configuration
     This function returns a new object representing XEmacs's current
     window configuration, namely the number of windows, their sizes
     and current buffers, which window is the selected window, and for
     each window the displayed buffer, the display-start position, and
     the positions of point and the mark.  An exception is made for
     point in the current buffer, whose value is not saved.

 - Function: set-window-configuration CONFIGURATION
     This function restores the configuration of XEmacs's windows and
     buffers to the state specified by CONFIGURATION.  The argument
     CONFIGURATION must be a value that was previously returned by
     `current-window-configuration'.

     This function always counts as a window size change and triggers
     execution of the `window-size-change-functions'.  (It doesn't know
     how to tell whether the new configuration actually differs from
     the old one.)

     Here is a way of using this function to get the same effect as
     `save-window-excursion':

          (let ((config (current-window-configuration)))
            (unwind-protect
                (progn (split-window-vertically nil)
                       ...)
              (set-window-configuration config)))

 - Special Form: save-window-excursion FORMS...
     This special form records the window configuration, executes FORMS
     in sequence, then restores the earlier window configuration.  The
     window configuration includes the value of point and the portion
     of the buffer that is visible.  It also includes the choice of
     selected window.  However, it does not include the value of point
     in the current buffer; use `save-excursion' if you wish to
     preserve that.

     Don't use this construct when `save-selected-window' is all you
     need.

     Exit from `save-window-excursion' always triggers execution of the
     `window-size-change-functions'.  (It doesn't know how to tell
     whether the restored configuration actually differs from the one in
     effect at the end of the FORMS.)

     The return value is the value of the final form in FORMS.  For
     example:

          (split-window)
               => #<window 25 on control.texi>
          (setq w (selected-window))
               => #<window 19 on control.texi>
          (save-window-excursion
            (delete-other-windows w)
            (switch-to-buffer "foo")
            'do-something)
               => do-something
               ;; The frame is now split again.

 - Function: window-configuration-p OBJECT
     This function returns `t' if OBJECT is a window configuration.

   Primitives to look inside of window configurations would make sense,
but none are implemented.  It is not clear they are useful enough to be
worth implementing.


File: lispref.info,  Node: Frames,  Next: Consoles and Devices,  Prev: Windows,  Up: Top

Frames
******

   A FRAME is a rectangle on the screen that contains one or more Emacs
windows.  A frame initially contains a single main window (plus perhaps
a minibuffer window), which you can subdivide vertically or
horizontally into smaller windows.

   When XEmacs runs on a text-only terminal, it starts with one "TTY
frame".  If you create additional ones, XEmacs displays one and only
one at any given time--on the terminal screen, of course.

   When XEmacs communicates directly with an X server, it does not have
a TTY frame; instead, it starts with a single "X window frame".  It can
display multiple X window frames at the same time, each in its own X
window.

 - Function: framep OBJECT
     This predicate returns `t' if OBJECT is a frame, and `nil'
     otherwise.

* Menu:

* Creating Frames::		Creating additional frames.
* Frame Parameters::		Controlling frame size, position, font, etc.
* Frame Titles::                Automatic updating of frame titles.
* Deleting Frames::		Frames last until explicitly deleted.
* Finding All Frames::		How to examine all existing frames.
* Frames and Windows::		A frame contains windows;
				  display of text always works through windows.
* Minibuffers and Frames::	How a frame finds the minibuffer to use.
* Input Focus::			Specifying the selected frame.
* Visibility of Frames::	Frames may be visible or invisible, or icons.
* Raising and Lowering::	Raising a frame makes it hide other X windows;
				  lowering it makes the others hide them.
* Frame Configurations::	Saving the state of all frames.
* Frame Hooks::                 Hooks for customizing frame behavior.

   *Note Display::, for related information.


File: lispref.info,  Node: Creating Frames,  Next: Frame Parameters,  Up: Frames

Creating Frames
===============

   To create a new frame, call the function `make-frame'.

 - Function: make-frame &optional ALIST DEVICE
     This function creates a new frame on DEVICE, if DEVICE permits
     creation of frames.  (An X server does; an ordinary terminal does
     not.)  DEVICE defaults to the selected device if omitted.  *Note
     Consoles and Devices::.

     The argument is an alist specifying frame parameters.  Any
     parameters not mentioned in ALIST default according to the value
     of the variable `default-frame-alist'.  For X devices, parameters
     not specified in `default-frame-alist' default in turn from
     `default-x-frame-alist' and, if not specified there, from the X
     resources.  For TTY devices, `default-tty-frame-alist' is
     consulted as well as `default-frame-alist'.

     The set of possible parameters depends in principle on what kind of
     window system XEmacs uses to display its frames.  *Note X Frame
     Parameters::, for documentation of individual parameters you can
     specify when creating an X window frame.


File: lispref.info,  Node: Frame Parameters,  Next: Frame Titles,  Prev: Creating Frames,  Up: Frames

Frame Parameters
================

   A frame has many parameters that control its appearance and behavior.
Just what parameters a frame has depends on what display mechanism it
uses.

   Frame parameters exist for the sake of window systems.  A terminal
frame has a few parameters, mostly for compatibility's sake; only the
height, width and `buffer-predicate' parameters really do something.

* Menu:

* Parameter Access::       How to change a frame's parameters.
* Initial Parameters::	   Specifying frame parameters when you make a frame.
* X Frame Parameters::     List of frame parameters.
* Size and Position::      Changing the size and position of a frame.
* Frame Name::             The name of a frame (as opposed to its title).


File: lispref.info,  Node: Parameter Access,  Next: Initial Parameters,  Up: Frame Parameters

Access to Frame Parameters
--------------------------

   These functions let you read and change the parameter values of a
frame.

 - Function: frame-parameters FRAME
     The function `frame-parameters' returns an alist listing all the
     parameters of FRAME and their values.

 - Function: modify-frame-parameters FRAME ALIST
     This function alters the parameters of frame FRAME based on the
     elements of ALIST.  Each element of ALIST has the form `(PARM .
     VALUE)', where PARM is a symbol naming a parameter.  If you don't
     mention a parameter in ALIST, its value doesn't change.


File: lispref.info,  Node: Initial Parameters,  Next: X Frame Parameters,  Prev: Parameter Access,  Up: Frame Parameters

Initial Frame Parameters
------------------------

   You can specify the parameters for the initial startup frame by
setting `initial-frame-alist' in your `.emacs' file.

 - Variable: initial-frame-alist
     This variable's value is an alist of parameter values used when
     creating the initial X window frame.  Each element has the form:

          (PARAMETER . VALUE)

     Emacs creates the initial frame before it reads your `~/.emacs'
     file.  After reading that file, Emacs checks `initial-frame-alist',
     and applies the parameter settings in the altered value to the
     already created initial frame.

     If these settings affect the frame geometry and appearance, you'll
     see the frame appear with the wrong ones and then change to the
     specified ones.  If that bothers you, you can specify the same
     geometry and appearance with X resources; those do take affect
     before the frame is created.  *Note X Resources: (emacs)Resources
     X.

     X resource settings typically apply to all frames.  If you want to
     specify some X resources solely for the sake of the initial frame,
     and you don't want them to apply to subsequent frames, here's how
     to achieve this.  Specify parameters in `default-frame-alist' to
     override the X resources for subsequent frames; then, to prevent
     these from affecting the initial frame, specify the same
     parameters in `initial-frame-alist' with values that match the X
     resources.

   If these parameters specify a separate minibuffer-only frame with
`(minibuffer . nil)', and you have not created one, Emacs creates one
for you.

 - Variable: minibuffer-frame-alist
     This variable's value is an alist of parameter values used when
     creating an initial minibuffer-only frame--if such a frame is
     needed, according to the parameters for the main initial frame.

 - Variable: default-frame-alist
     This is an alist specifying default values of frame parameters for
     subsequent Emacs frames (not the initial ones).

   See also `special-display-frame-alist', in *Note Choosing Window::.

   If you use options that specify window appearance when you invoke
Emacs, they take effect by adding elements to `default-frame-alist'.
One exception is `-geometry', which adds the specified position to
`initial-frame-alist' instead.  *Note Command Arguments: (emacs)Command
Arguments.


File: lispref.info,  Node: X Frame Parameters,  Next: Size and Position,  Prev: Initial Parameters,  Up: Frame Parameters

X Window Frame Parameters
-------------------------

   Just what parameters a frame has depends on what display mechanism it
uses.  Here is a table of the parameters of an X window frame; of these,
`name', `height', `width', and `buffer-predicate' provide meaningful
information in non-X frames.

`name'
     The name of the frame.  Most window managers display the frame's
     name in the frame's border, at the top of the frame.  If you don't
     specify a name, and you have more than one frame, Emacs sets the
     frame name based on the buffer displayed in the frame's selected
     window.

     If you specify the frame name explicitly when you create the
     frame, the name is also used (instead of the name of the Emacs
     executable) when looking up X resources for the frame.

`display'
     The display on which to open this frame.  It should be a string of
     the form `"HOST:DPY.SCREEN"', just like the `DISPLAY' environment
     variable.

`left'
     The screen position of the left edge, in pixels, with respect to
     the left edge of the screen.  The value may be a positive number
     POS, or a list of the form `(+ POS)' which permits specifying a
     negative POS value.

     A negative number -POS, or a list of the form `(- POS)', actually
     specifies the position of the right edge of the window with
     respect to the right edge of the screen.  A positive value of POS
     counts toward the left.  If the parameter is a negative integer
     -POS then POS is positive!

`top'
     The screen position of the top edge, in pixels, with respect to the
     top edge of the screen.  The value may be a positive number POS,
     or a list of the form `(+ POS)' which permits specifying a
     negative POS value.

     A negative number -POS, or a list of the form `(- POS)', actually
     specifies the position of the bottom edge of the window with
     respect to the bottom edge of the screen.  A positive value of POS
     counts toward the top.  If the parameter is a negative integer
     -POS then POS is positive!

`icon-left'
     The screen position of the left edge *of the frame's icon*, in
     pixels, counting from the left edge of the screen.  This takes
     effect if and when the frame is iconified.

`icon-top'
     The screen position of the top edge *of the frame's icon*, in
     pixels, counting from the top edge of the screen.  This takes
     effect if and when the frame is iconified.

`user-position'
     Non-`nil' if the screen position of the frame was explicitly
     requested by the user (for example, with the `-geometry' option).
     Nothing automatically makes this parameter non-`nil'; it is up to
     Lisp programs that call `make-frame' to specify this parameter as
     well as specifying the `left' and `top' parameters.

`height'
     The height of the frame contents, in characters.  (To get the
     height in pixels, call `frame-pixel-height'; see *Note Size and
     Position::.)

`width'
     The width of the frame contents, in characters.  (To get the
     height in pixels, call `frame-pixel-width'; see *Note Size and
     Position::.)

`window-id'
     The number of the X window for the frame.

`minibuffer'
     Whether this frame has its own minibuffer.  The value `t' means
     yes, `nil' means no, `only' means this frame is just a minibuffer.
     If the value is a minibuffer window (in some other frame), the
     new frame uses that minibuffer. (Minibuffer-only and
     minibuffer-less frames are not yet implemented in XEmacs.)

`buffer-predicate'
     The buffer-predicate function for this frame.  The function
     `other-buffer' uses this predicate (from the selected frame) to
     decide which buffers it should consider, if the predicate is not
     `nil'.  It calls the predicate with one arg, a buffer, once for
     each buffer; if the predicate returns a non-`nil' value, it
     considers that buffer.

`scroll-bar-width'
     The width of the vertical scroll bar, in pixels.

`cursor-color'
     The color for the cursor that shows point.

`border-color'
     The color for the border of the frame.

`border-width'
     The width in pixels of the window border.

`internal-border-width'
     The distance in pixels between text and border.

`unsplittable'
     If non-`nil', this frame's window is never split automatically.

`inter-line-space'
     The space in pixels between adjacent lines of text. (Not currently
     implemented.)

`modeline'
     Whether the frame has a modeline.


File: lispref.info,  Node: Size and Position,  Next: Frame Name,  Prev: X Frame Parameters,  Up: Frame Parameters

Frame Size And Position
-----------------------

   You can read or change the size and position of a frame using the
frame parameters `left', `top', `height', and `width'.  Whatever
geometry parameters you don't specify are chosen by the window manager
in its usual fashion.

   Here are some special features for working with sizes and positions:

 - Function: set-frame-position FRAME LEFT TOP
     This function sets the position of the top left corner of FRAME to
     LEFT and TOP.  These arguments are measured in pixels, and count
     from the top left corner of the screen.  Negative parameter values
     count up or rightward from the top left corner of the screen.

 - Function: frame-height &optional FRAME
 - Function: frame-width &optional FRAME
     These functions return the height and width of FRAME, measured in
     lines and columns.  If you don't supply FRAME, they use the
     selected frame.

 - Function: frame-pixel-height &optional FRAME
 - Function: frame-pixel-width &optional FRAME
     These functions return the height and width of FRAME, measured in
     pixels.  If you don't supply FRAME, they use the selected frame.

 - Function: set-frame-size FRAME COLS ROWS &optional PRETEND
     This function sets the size of FRAME, measured in characters; COLS
     and ROWS specify the new width and height.  (If PRETEND is
     non-nil, it means that redisplay should act as if the frame's size
     is COLS by ROWS, but the actual size of the frame should not be
     changed.  You should not normally use this option.)

   You can also use the functions `set-frame-height' and
`set-frame-width' to set the height and width individually.  The frame
is the first argument and the size (in rows or columns) is the second.
(There is an optional third argument, PRETEND, which has the same
purpose as the corresponding argument in `set-frame-size'.)


File: lispref.info,  Node: Frame Name,  Prev: Size and Position,  Up: Frame Parameters

The Name of a Frame (As Opposed to Its Title)
---------------------------------------------

   Under X, every frame has a name, which is not the same as the title
of the frame.  A frame's name is used to look up its resources and does
not normally change over the lifetime of a frame.  It is perfectly
allowable, and quite common, for multiple frames to have the same name.

 - Function: frame-name &optional FRAME
     This function returns the name of FRAME, which defaults to the
     selected frame if not specified.  The name of a frame can also be
     obtained from the frame's parameters.  *Note Frame Parameters::.

 - Variable: default-frame-name
     This variable holds the default name to assign to newly-created
     frames.  This can be overridden by arguments to `make-frame'.  This
     must be a string.


File: lispref.info,  Node: Frame Titles,  Next: Deleting Frames,  Prev: Frame Parameters,  Up: Frames

Frame Titles
============

   Every frame has a title; most window managers display the frame
title at the top of the frame.  You can specify an explicit title with
the `name' frame property.  But normally you don't specify this
explicitly, and Emacs computes the title automatically.

   Emacs computes the frame title based on a template stored in the
variable `frame-title-format'.

 - Variable: frame-title-format
     This variable specifies how to compute a title for a frame when
     you have not explicitly specified one.

     The variable's value is actually a modeline construct, just like
     `modeline-format'.  *Note Modeline Data::.

 - Variable: frame-icon-title-format
     This variable specifies how to compute the title for an iconified
     frame, when you have not explicitly specified the frame title.
     This title appears in the icon itself.

 - Function: x-set-frame-icon-pixmap FRAME PIXMAP &optional MASK
     This function sets the icon of the given frame to the given image
     instance, which should be an image instance object (as returned by
     `make-image-instance'), a glyph object (as returned by
     `make-glyph'), or `nil'.  If a glyph object is given, the glyph
     will be instantiated on the frame to produce an image instance
     object.

     If the given image instance has a mask, that will be used as the
     icon mask; however, not all window managers support this.

     The window manager is also not required to support color pixmaps,
     only bitmaps (one plane deep).

     If the image instance does not have a mask, then the optional
     third argument may be the image instance to use as the mask (it
     must be one plane deep).  *Note Glyphs::.


File: lispref.info,  Node: Deleting Frames,  Next: Finding All Frames,  Prev: Frame Titles,  Up: Frames

Deleting Frames
===============

   Frames remain potentially visible until you explicitly "delete"
them.  A deleted frame cannot appear on the screen, but continues to
exist as a Lisp object until there are no references to it.

 - Command: delete-frame &optional FRAME
     This function deletes the frame FRAME.  By default, FRAME is the
     selected frame.

 - Function: frame-live-p FRAME
     The function `frame-live-p' returns non-`nil' if the frame FRAME
     has not been deleted.


File: lispref.info,  Node: Finding All Frames,  Next: Frames and Windows,  Prev: Deleting Frames,  Up: Frames

Finding All Frames
==================

 - Function: frame-list
     The function `frame-list' returns a list of all the frames that
     have not been deleted.  It is analogous to `buffer-list' for
     buffers.  The list that you get is newly created, so modifying the
     list doesn't have any effect on the internals of XEmacs.

 - Function: device-frame-list &optional DEVICE
     This function returns a list of all frames on DEVICE.  If DEVICE
     is `nil', the selected device will be used.

 - Function: visible-frame-list &optional DEVICE
     This function returns a list of just the currently visible frames.
     If DEVICE is specified only frames on that device will be returned.
     *Note Visibility of Frames::.  (TTY frames always count as
     "visible", even though only the selected one is actually
     displayed.)

 - Function: next-frame &optional FRAME MINIBUF
     The function `next-frame' lets you cycle conveniently through all
     the frames from an arbitrary starting point.  It returns the "next"
     frame after FRAME in the cycle.  If FRAME is omitted or `nil', it
     defaults to the selected frame.

     The second argument, MINIBUF, says which frames to consider:

    `nil'
          Exclude minibuffer-only frames.

    `visible'
          Consider all visible frames.

    0
          Consider all visible or iconified frames.

    a window
          Consider only the frames using that particular window as their
          minibuffer.

    the symbol `visible'
          Include all visible frames.

    `0'
          Include all visible and iconified frames.

    anything else
          Consider all frames.

 - Function: previous-frame &optional FRAME MINIBUF
     Like `next-frame', but cycles through all frames in the opposite
     direction.

   See also `next-window' and `previous-window', in *Note Cyclic Window
Ordering::.


File: lispref.info,  Node: Frames and Windows,  Next: Minibuffers and Frames,  Prev: Finding All Frames,  Up: Frames

Frames and Windows
==================

   Each window is part of one and only one frame; you can get the frame
with `window-frame'.

 - Function: frame-root-window &optional FRAME
     This returns the root window of frame FRAME.  FRAME defaults to
     the selected frame if not specified.

 - Function: window-frame &optional WINDOW
     This function returns the frame that WINDOW is on.  WINDOW
     defaults to the selected window if omitted.

   All the non-minibuffer windows in a frame are arranged in a cyclic
order.  The order runs from the frame's top window, which is at the
upper left corner, down and to the right, until it reaches the window at
the lower right corner (always the minibuffer window, if the frame has
one), and then it moves back to the top.

 - Function: frame-top-window FRAME
     This returns the topmost, leftmost window of frame FRAME.

   At any time, exactly one window on any frame is "selected within the
frame".  The significance of this designation is that selecting the
frame also selects this window.  You can get the frame's current
selected window with `frame-selected-window'.

 - Function: frame-selected-window &optional FRAME
     This function returns the window on FRAME that is selected within
     FRAME.  FRAME defaults to the selected frame if not specified.

   Conversely, selecting a window for XEmacs with `select-window' also
makes that window selected within its frame.  *Note Selecting Windows::.

   Another function that (usually) returns one of the windows in a
frame is `minibuffer-window'.  *Note Minibuffer Misc::.

