@c -*-texinfo-*-
@c This is part of the XEmacs Lisp Reference Manual.
@c Copyright (C) 1990, 1991, 1992, 1993, 1994 Free Software Foundation, Inc. 
@c Copyright (C) 1995, 1996 Ben Wing.
@c See the file lispref.texi for copying conditions.
@setfilename ../../info/frames.info
@node Frames, Consoles and Devices, Windows, Top
@chapter Frames
@cindex frame

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

@cindex terminal frame
@cindex X window frame
  When XEmacs runs on a text-only terminal, it starts with one
@dfn{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 @dfn{X window frame}.
It can display multiple X window frames at the same time, each in its
own X window.

@defun framep object
This predicate returns @code{t} if @var{object} is a frame, and
@code{nil} otherwise.
@end defun

@menu
* Creating Frames::		Creating additional frames.
* Frame Properties::		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.
@end menu

  @xref{Display}, for related information.

@node Creating Frames
@section Creating Frames

To create a new frame, call the function @code{make-frame}.

@defun make-frame &optional props device
This function creates a new frame on @var{device}, if @var{device}
permits creation of frames.  (An X server does; an ordinary terminal
does not (yet).)  @var{device} defaults to the selected device if omitted.
@xref{Consoles and Devices}.

The argument @var{props} is a property list (a list of alternating
keyword-value specifications) of properties for the new frame. (An alist
is accepted for backward compatibility but should not be passed in.) Any
properties not mentioned in @var{props} default according to the value
of the variable @code{default-frame-plist}.  For X devices, properties
not specified in @code{default-frame-plist} default in turn from
@code{default-x-frame-plist} and, if not specified there, from the X
resources.  For TTY devices, @code{default-tty-frame-plist} is consulted
as well as @code{default-frame-plist}.

The set of possible properties depends in principle on what kind of
window system XEmacs uses to display its frames.  @xref{X Frame
Properties}, for documentation of individual properties you can specify
when creating an X window frame.
@end defun

@node Frame Properties
@section Frame Properties

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

Frame properties exist for the sake of window systems.  A terminal frame
has few properties, mostly for compatibility's sake; only the height,
width and @code{buffer-predicate} properties really do something.

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

@node Property Access
@subsection Access to Frame Properties

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

@defun frame-properties &optional frame
This function returns a plist listing all the properties of @var{frame}
and their values.
@end defun

@defun frame-property frame property &optional default
This function returns @var{frame}'s value for the property
@var{property}.
@end defun

@defun set-frame-properties frame plist
This function alters the properties of frame @var{frame} based on the
elements of property list @var{plist}.  If you don't mention a property
in @var{plist}, its value doesn't change.
@end defun

@defun set-frame-property frame prop val
This function sets the property @var{prop} of frame @var{frame} to the
value @var{val}.
@end defun

@node Initial Properties
@subsection Initial Frame Properties

You can specify the properties for the initial startup frame by setting
@code{initial-frame-plist} in your @file{.emacs} file.

@defvar initial-frame-plist
This variable's value is a plist of alternating property-value pairs
used when creating the initial X window frame.

XEmacs creates the initial frame before it reads your @file{~/.emacs}
file.  After reading that file, XEmacs checks @code{initial-frame-plist},
and applies the property 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.  @xref{Resources X,, X Resources, xemacs, The XEmacs User's Manual}.

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 properties in @code{default-frame-plist} to override the X
resources for subsequent frames; then, to prevent these from affecting
the initial frame, specify the same properties in
@code{initial-frame-plist} with values that match the X resources.
@end defvar

If these properties specify a separate minibuffer-only frame via a
@code{minibuffer} property of @code{nil}, and you have not yet created
one, XEmacs creates one for you.

@defvar minibuffer-frame-plist
This variable's value is a plist of properties used when creating an
initial minibuffer-only frame---if such a frame is needed, according to
the properties for the main initial frame.
@end defvar

@defvar default-frame-plist
This is a plist specifying default values of frame properties for
subsequent XEmacs frames (not the initial ones).
@end defvar

See also @code{special-display-frame-plist}, in @ref{Choosing Window}.

If you use options that specify window appearance when you invoke XEmacs,
they take effect by adding elements to @code{default-frame-plist}.  One
exception is @samp{-geometry}, which adds the specified position to
@code{initial-frame-plist} instead.  @xref{Command Arguments,,, xemacs,
The XEmacs User's Manual}.

@node X Frame Properties
@subsection X Window Frame Properties

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

@table @code
@item 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, XEmacs 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 XEmacs executable) when
looking up X resources for the frame.

@item display
The display on which to open this frame.  It should be a string of the
form @code{"@var{host}:@var{dpy}.@var{screen}"}, just like the
@code{DISPLAY} environment variable.

@item 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 @var{pos},
or a list of the form @code{(+ @var{pos})} which permits specifying a
negative @var{pos} value.

A negative number @minus{}@var{pos}, or a list of the form @code{(-
@var{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 @var{pos} counts toward the left.  If the property is a negative
integer @minus{}@var{pos} then @var{pos} is positive!

@item 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 @var{pos},
or a list of the form @code{(+ @var{pos})} which permits specifying a
negative @var{pos} value.

A negative number @minus{}@var{pos}, or a list of the form @code{(-
@var{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 @var{pos} counts toward the top.  If the property is a negative
integer @minus{}@var{pos} then @var{pos} is positive!

@item icon-left
The screen position of the left edge @emph{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.

@item icon-top
The screen position of the top edge @emph{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.

@item user-position
Non-@code{nil} if the screen position of the frame was explicitly
requested by the user (for example, with the @samp{-geometry} option).
Nothing automatically makes this property non-@code{nil}; it is up to
Lisp programs that call @code{make-frame} to specify this property as
well as specifying the @code{left} and @code{top} properties.

@item height
The height of the frame contents, in characters.  (To get the height in
pixels, call @code{frame-pixel-height}; see @ref{Size and Position}.)

@item width
The width of the frame contents, in characters.  (To get the height in
pixels, call @code{frame-pixel-width}; see @ref{Size and Position}.)

@item window-id
The number of the X window for the frame.

@item minibuffer
Whether this frame has its own minibuffer.  The value @code{t} means
yes, @code{nil} means no, @code{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.)

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

@item scroll-bar-width
The width of the vertical scroll bar, in pixels.

@ignore Not in XEmacs
@item icon-type
The type of icon to use for this frame when it is iconified.  If the
value is a string, that specifies a file containing a bitmap to use.
Any other non-@code{nil} value specifies the default bitmap icon (a
picture of a gnu); @code{nil} specifies a text icon.

@item icon-name
The name to use in the icon for this frame, when and if the icon
appears.  If this is @code{nil}, the frame's title is used.
@end ignore

@item cursor-color
The color for the cursor that shows point.

@item border-color
The color for the border of the frame.

@ignore Not in XEmacs
@item cursor-type
The way to display the cursor.  The legitimate values are @code{bar},
@code{box}, and @code{(bar . @var{width})}.  The symbol @code{box}
specifies an ordinary black box overlaying the character after point;
that is the default.  The symbol @code{bar} specifies a vertical bar
between characters as the cursor.  @code{(bar . @var{width})} specifies
a bar @var{width} pixels wide.
@end ignore

@item border-width
The width in pixels of the window border.

@item internal-border-width
The distance in pixels between text and border.

@item unsplittable
If non-@code{nil}, this frame's window is never split automatically.

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

@item modeline
Whether the frame has a modeline.
@end table

@node Size and Position
@subsection Frame Size And Position
@cindex size of frame
@cindex frame size
@cindex display lines
@cindex display columns
@cindex resize redisplay
@cindex frame position
@cindex position of frame

  You can read or change the size and position of a frame using the
frame properties @code{left}, @code{top}, @code{height}, and
@code{width}.  Whatever geometry properties 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:

@defun set-frame-position frame left top
This function sets the position of the top left corner of @var{frame} to
@var{left} and @var{top}.  These arguments are measured in pixels, and
count from the top left corner of the screen.  Negative property values
count up or rightward from the top left corner of the screen.
@end defun

@defun frame-height &optional frame
@defunx frame-width &optional frame
These functions return the height and width of @var{frame}, measured in
lines and columns.  If you don't supply @var{frame}, they use the selected
frame.
@end defun

@defun frame-pixel-height &optional frame
@defunx frame-pixel-width &optional frame
These functions return the height and width of @var{frame}, measured in
pixels.  If you don't supply @var{frame}, they use the selected frame.
@end defun

@defun set-frame-size frame cols rows &optional pretend
This function sets the size of @var{frame}, measured in characters;
@var{cols} and @var{rows} specify the new width and height.  (If
@var{pretend} is non-nil, it means that redisplay should act as if
the frame's size is @var{cols} by @var{rows}, but the actual size
of the frame should not be changed.  You should not normally use
this option.)
@end defun

  You can also use the functions @code{set-frame-height} and
@code{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, @var{pretend},
which has the same purpose as the corresponding argument in
@code{set-frame-size}.)

@ignore  @c Not in XEmacs
@defun x-parse-geometry geom
@cindex geometry specification
The function @code{x-parse-geometry} converts a standard X windows
geometry string to a plist that you can use as part of the argument to
@code{make-frame}.

The plist describes which properties were specified in @var{geom}, and
gives the values specified for them.  Each element looks like
@code{(@var{property} . @var{value})}.  The possible @var{property}
values are @code{left}, @code{top}, @code{width}, and @code{height}.

For the size properties, the value must be an integer.  The position
property names @code{left} and @code{top} are not totally accurate,
because some values indicate the position of the right or bottom edges
instead.  These are the @var{value} possibilities for the position
properties:

@table @asis
@item an integer
A positive integer relates the left edge or top edge of the window to
the left or top edge of the screen.  A negative integer relates the
right or bottom edge of the window to the right or bottom edge of the
screen.

@item @code{(+ @var{position})}
This specifies the position of the left or top edge of the window
relative to the left or top edge of the screen.  The integer
@var{position} may be positive or negative; a negative value specifies a
position outside the screen.

@item @code{(- @var{position})}
This specifies the position of the right or bottom edge of the window
relative to the right or bottom edge of the screen.  The integer
@var{position} may be positive or negative; a negative value specifies a
position outside the screen.
@end table

Here is an example:

@example
(x-parse-geometry "35x70+0-0")
     @result{} ((width . 35) (height . 70)
         (left . 0) (top - 0))
@end example
@end defun
@end ignore

@node Frame Name
@subsection The Name of a Frame (As Opposed to Its Title)
@cindex frame name

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.

@defun frame-name &optional frame
This function returns the name of @var{frame}, which defaults to the
selected frame if not specified.  The name of a frame can also be
obtained from the frame's properties.  @xref{Frame Properties}.
@end defun

@defvar default-frame-name
This variable holds the default name to assign to newly-created frames.
This can be overridden by arguments to @code{make-frame}.  This
must be a string.
@end defvar

@node Frame Titles
@section 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
@code{name} frame property.  But normally you don't specify this
explicitly, and XEmacs computes the title automatically.

XEmacs computes the frame title based on a template stored in the
variable @code{frame-title-format}.

@defvar 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
@code{modeline-format}.  @xref{Modeline Data}.
@end defvar

@defvar 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.
@end defvar

@defun 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
@code{make-image-instance}), a glyph object (as returned by
@code{make-glyph}), or @code{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).
@xref{Glyphs}.
@end defun

@node Deleting Frames
@section Deleting Frames
@cindex deletion of frames

Frames remain potentially visible until you explicitly @dfn{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.

@deffn Command delete-frame &optional frame
This function deletes the frame @var{frame}.  By default, @var{frame} is
the selected frame.
@end deffn

@defun frame-live-p frame
The function @code{frame-live-p} returns non-@code{nil} if the frame
@var{frame} has not been deleted.
@end defun

@ignore Not in XEmacs currently
  Some window managers provide a command to delete a window.  These work
by sending a special message to the program that operates the window.
When XEmacs gets one of these commands, it generates a
@code{delete-frame} event, whose normal definition is a command that
calls the function @code{delete-frame}.  @xref{Misc Events}.
@end ignore

@node Finding All Frames
@section Finding All Frames

@defun frame-list
The function @code{frame-list} returns a list of all the frames that
have not been deleted.  It is analogous to @code{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.
@end defun

@defun device-frame-list &optional device
This function returns a list of all frames on @var{device}.  If
@var{device} is @code{nil}, the selected device will be used.
@end defun

@defun visible-frame-list &optional device
This function returns a list of just the currently visible frames.
If @var{device} is specified only frames on that device will be returned.
@xref{Visibility of Frames}.  (TTY frames always count as
``visible'', even though only the selected one is actually displayed.)
@end defun

@defun next-frame &optional frame minibuf
The function @code{next-frame} lets you cycle conveniently through all
the frames from an arbitrary starting point.  It returns the ``next''
frame after @var{frame} in the cycle.  If @var{frame} is omitted or
@code{nil}, it defaults to the selected frame.

The second argument, @var{minibuf}, says which frames to consider:

@table @asis
@item @code{nil}
Exclude minibuffer-only frames.
@item @code{visible}
Consider all visible frames.
@item 0
Consider all visible or iconified frames.
@item a window
Consider only the frames using that particular window as their
minibuffer.
@item the symbol @code{visible}
Include all visible frames.
@item @code{0}
Include all visible and iconified frames.
@item anything else
Consider all frames.
@end table
@end defun

@defun previous-frame &optional frame minibuf
Like @code{next-frame}, but cycles through all frames in the opposite
direction.
@end defun

  See also @code{next-window} and @code{previous-window}, in @ref{Cyclic
Window Ordering}.

@node Frames and Windows
@section Frames and Windows

  Each window is part of one and only one frame; you can get the frame
with @code{window-frame}.

@defun frame-root-window &optional frame
This returns the root window of frame @var{frame}.  @var{frame}
defaults to the selected frame if not specified.
@end defun

@defun window-frame &optional window
This function returns the frame that @var{window} is on.  @var{window}
defaults to the selected window if omitted.
@end defun

  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.

@defun frame-top-window frame
This returns the topmost, leftmost window of frame @var{frame}.
@end defun

At any time, exactly one window on any frame is @dfn{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 @code{frame-selected-window}.

@defun frame-selected-window &optional frame
This function returns the window on @var{frame} that is selected within
@var{frame}.  @var{frame} defaults to the selected frame if not
specified.
@end defun

Conversely, selecting a window for XEmacs with @code{select-window} also
makes that window selected within its frame.  @xref{Selecting Windows}.

Another function that (usually) returns one of the windows in a frame is
@code{minibuffer-window}.  @xref{Minibuffer Misc}.

@node Minibuffers and Frames
@section Minibuffers and Frames

Normally, each frame has its own minibuffer window at the bottom, which
is used whenever that frame is selected.  If the frame has a minibuffer,
you can get it with @code{minibuffer-window} (@pxref{Minibuffer Misc}).

However, you can also create a frame with no minibuffer.  Such a frame
must use the minibuffer window of some other frame.  When you create the
frame, you can specify explicitly the minibuffer window to use (in some
other frame).  If you don't, then the minibuffer is found in the frame
which is the value of the variable @code{default-minibuffer-frame}.  Its
value should be a frame which does have a minibuffer.

@ignore Not yet in XEmacs
If you use a minibuffer-only frame, you might want that frame to raise
when you enter the minibuffer.  If so, set the variable
@code{minibuffer-auto-raise} to @code{t}.  @xref{Raising and Lowering}.
@end ignore

@defvar default-minibuffer-frame
This variable specifies the frame to use for the minibuffer window, by
default.
@end defvar

@node Input Focus
@section Input Focus
@cindex input focus
@cindex selected frame

At any time, one frame in XEmacs is the @dfn{selected frame}.  The selected
window always resides on the selected frame.  As the focus moves from
device to device, the selected frame on each device is remembered and
restored when the focus moves back to that device.

@defun selected-frame &optional device
This function returns the selected frame on @var{device}.  If
@var{device} is not specified, the selected device will be used.  If no
frames exist on the device, @code{nil} is returned.
@end defun

The X server normally directs keyboard input to the X window that the
mouse is in.  Some window managers use mouse clicks or keyboard events
to @dfn{shift the focus} to various X windows, overriding the normal
behavior of the server.

Lisp programs can switch frames ``temporarily'' by calling
the function @code{select-frame}.  This does not override the window
manager; rather, it escapes from the window manager's control until
that control is somehow reasserted.

When using a text-only terminal, there is no window manager; therefore,
@code{select-frame} is the only way to switch frames, and the effect
lasts until overridden by a subsequent call to @code{select-frame}.
Only the selected terminal frame is actually displayed on the terminal.
Each terminal screen except for the initial one has a number, and the
number of the selected frame appears in the mode line after the word
@samp{XEmacs} (@pxref{Modeline Variables}).

@defun select-frame frame
This function selects frame @var{frame}, temporarily disregarding the
focus of the X server if any.  The selection of @var{frame} lasts until
the next time the user does something to select a different frame, or
until the next time this function is called.

Note that @code{select-frame} does not actually cause the window-system
focus to be set to this frame, or the @code{select-frame-hook} or
@code{deselect-frame-hook} to be run, until the next time that XEmacs is
waiting for an event.

Also note that when the variable @code{focus-follows-mouse} is
non-@code{nil}, the frame selection is temporary and is reverted when
the current command terminates, much like the buffer selected by
@code{set-buffer}.  In order to effect a permanent focus change use
@code{focus-frame}.
@end defun

@defun focus-frame frame
This function selects @var{frame} and gives it the window system focus.
The operation of @code{focus-frame} is not affected by the value of
@code{focus-follows-mouse}.
@end defun

@defmac save-selected-frame forms@dots{}
This macro records the selected frame, executes @var{forms} in sequence,
then restores the earlier selected frame.  The value returned is the
value of the last form.
@end defmac

@defmac with-selected-frame frame forms@dots{}
This macro records the selected frame, then selects @var{frame} and
executes @var{forms} in sequence.  After the last form is finished, the
earlier selected frame is restored.  The value returned is the value of
the last form.
@end defmac

@ignore (FSF Emacs, continued from defun select-frame)
XEmacs cooperates with the X server and the window managers by arranging
to select frames according to what the server and window manager ask
for.  It does so by generating a special kind of input event, called a
@dfn{focus} event.  The command loop handles a focus event by calling
@code{handle-select-frame}.  @xref{Focus Events}.

@deffn Command handle-switch-frame frame
This function handles a focus event by selecting frame @var{frame}.

Focus events normally do their job by invoking this command.
Don't call it for any other reason.
@end deffn

@defun redirect-frame-focus frame focus-frame
This function redirects focus from @var{frame} to @var{focus-frame}.
This means that @var{focus-frame} will receive subsequent keystrokes
intended for @var{frame}.  After such an event, the value of
@code{last-event-frame} will be @var{focus-frame}.  Also, switch-frame
events specifying @var{frame} will instead select @var{focus-frame}.

If @var{focus-frame} is @code{nil}, that cancels any existing
redirection for @var{frame}, which therefore once again receives its own
events.

One use of focus redirection is for frames that don't have minibuffers.
These frames use minibuffers on other frames.  Activating a minibuffer
on another frame redirects focus to that frame.  This puts the focus on
the minibuffer's frame, where it belongs, even though the mouse remains
in the frame that activated the minibuffer.

Selecting a frame can also change focus redirections.  Selecting frame
@code{bar}, when @code{foo} had been selected, changes any redirections
pointing to @code{foo} so that they point to @code{bar} instead.  This
allows focus redirection to work properly when the user switches from
one frame to another using @code{select-window}.

This means that a frame whose focus is redirected to itself is treated
differently from a frame whose focus is not redirected.
@code{select-frame} affects the former but not the latter.

The redirection lasts until @code{redirect-frame-focus} is called to
change it.
@end defun
@end ignore

@node Visibility of Frames
@section Visibility of Frames
@cindex visible frame
@cindex invisible frame
@cindex iconified frame
@cindex frame visibility

An X window frame may be @dfn{visible}, @dfn{invisible}, or
@dfn{iconified}.  If it is visible, you can see its contents.  If it is
iconified, the frame's contents do not appear on the screen, but an icon
does.  If the frame is invisible, it doesn't show on the screen, not
even as an icon.

Visibility is meaningless for TTY frames, since only the selected
one is actually displayed in any case.

@deffn Command make-frame-visible &optional frame
This function makes frame @var{frame} visible.  If you omit @var{frame},
it makes the selected frame visible.
@end deffn

@deffn Command make-frame-invisible &optional frame
This function makes frame @var{frame} invisible.
@end deffn

@deffn Command iconify-frame &optional frame
This function iconifies frame @var{frame}.
@end deffn

@deffn Command deiconify-frame &optional frame
This function de-iconifies frame @var{frame}.  Under X, this is
equivalent to @code{make-frame-visible}.
@end deffn

@defun frame-visible-p frame
This returns whether @var{frame} is currently ``visible'' (actually in
use for display).  A frame that is not visible is not updated, and, if
it works through a window system, may not show at all.
@end defun

@defun frame-iconified-p frame
This returns whether @var{frame} is iconified.  Not all window managers
use icons; some merely unmap the window, so this function is not the
inverse of @code{frame-visible-p}.  It is possible for a frame to not
be visible and not be iconified either.  However, if the frame is
iconified, it will not be visible.  (Under FSF Emacs, the functionality
of this function is obtained through @code{frame-visible-p}.)
@end defun

@defun frame-totally-visible-p frame
This returns whether @var{frame} is not obscured by any other X
windows.  On TTY frames, this is the same as @code{frame-visible-p}.
@end defun

@ignore  @c Not in XEmacs.
  The visibility status of a frame is also available as a frame
property.  You can read or change it as such.  @xref{X Frame
Properties}.

The user can iconify and deiconify frames with the window manager.  This
happens below the level at which XEmacs can exert any control, but XEmacs
does provide events that you can use to keep track of such changes.
@xref{Misc Events}.
@end ignore

@node Raising and Lowering
@section Raising and Lowering Frames

The X Window System uses a desktop metaphor.  Part of this metaphor is
the idea that windows are stacked in a notional third dimension
perpendicular to the screen surface, and thus ordered from ``highest''
to ``lowest''.  Where two windows overlap, the one higher up covers the
one underneath.  Even a window at the bottom of the stack can be seen if
no other window overlaps it.

@cindex raising a frame
@cindex lowering a frame
A window's place in this ordering is not fixed; in fact, users tend to
change the order frequently.  @dfn{Raising} a window means moving it
``up'', to the top of the stack.  @dfn{Lowering} a window means moving
it to the bottom of the stack.  This motion is in the notional third
dimension only, and does not change the position of the window on the
screen.

You can raise and lower XEmacs's X windows with these functions:

@deffn Command raise-frame &optional frame
This function raises frame @var{frame}.
@end deffn

@deffn Command lower-frame &optional frame
This function lowers frame @var{frame}.
@end deffn

You can also specify auto-raise (raising automatically when a frame is
selected) or auto-lower (lowering automatically when it is deselected).
Under X, most ICCCM-compliant window managers will have an option to do
this for you, but the following variables are provided in case you're
using a broken WM.  (Under FSF Emacs, the same functionality is
provided through the @code{auto-raise} and @code{auto-lower}
frame properties.)

@defvar auto-raise-frame
This variable's value is @code{t} if frames will be raised to the top
when selected.
@end defvar

@ignore Not in XEmacs
@defopt minibuffer-auto-raise
If this is non-@code{nil}, activation of the minibuffer raises the frame
that the minibuffer window is in.
@end defopt
@end ignore

@defvar auto-lower-frame
This variable's value is @code{t} if frames will be lowered to the bottom
when no longer selected.
@end defvar

Auto-raising and auto-lowering is implemented through functions attached
to @code{select-frame-hook} and @code{deselect-frame-hook}
(@pxref{Frame Hooks}).  Under normal circumstances, you should not call
these functions directly.

@defun default-select-frame-hook
This hook function implements the @code{auto-raise-frame} variable; it is
for use as the value of @code{select-frame-hook}.
@end defun

@defun default-deselect-frame-hook
This hook function implements the @code{auto-lower-frame} variable; it is
for use as the value of @code{deselect-frame-hook}.
@end defun

@node Frame Configurations
@section Frame Configurations
@cindex frame configuration

  A @dfn{frame configuration} records the current arrangement of frames,
all their properties, and the window configuration of each one.

@defun current-frame-configuration
This function returns a frame configuration list that describes
the current arrangement of frames and their contents.
@end defun

@defun set-frame-configuration configuration
This function restores the state of frames described in
@var{configuration}.
@end defun

@node Frame Hooks
@section Hooks for Customizing Frame Behavior
@cindex frame hooks

XEmacs provides many hooks that are called at various times during a
frame's lifetime.  @xref{Hooks}.

@defvar create-frame-hook
This hook is called each time a frame is created.  The functions are called
with one argument, the newly-created frame.
@end defvar

@defvar delete-frame-hook
This hook is called each time a frame is deleted.  The functions are called
with one argument, the about-to-be-deleted frame.
@end defvar

@defvar select-frame-hook
This is a normal hook that is run just after a frame is selected.  The
function @code{default-select-frame-hook}, which implements auto-raising
(@pxref{Raising and Lowering}), is normally attached to this hook.

Note that calling @code{select-frame} does not necessarily set the
focus: The actual window-system focus will not be changed until the next
time that XEmacs is waiting for an event, and even then, the window
manager may refuse the focus-change request.
@end defvar

@defvar deselect-frame-hook
This is a normal hook that is run just before a frame is deselected
(and another frame is selected).  The function
@code{default-deselect-frame-hook}, which implements auto-lowering
(@pxref{Raising and Lowering}), is normally attached to this hook.
@end defvar

@defvar map-frame-hook
This hook is called each time a frame is mapped (i.e. made visible).
The functions are called with one argument, the newly mapped frame.
@end defvar

@defvar unmap-frame-hook
This hook is called each time a frame is unmapped (i.e. made invisible
or iconified).  The functions are called with one argument, the
newly unmapped frame.
@end defvar
