@c -*-texinfo-*-
@c This is part of the GNU Emacs Lisp Reference Manual.
-@c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1998, 1999
-@c Free Software Foundation, Inc.
+@c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1998, 1999, 2002, 2003,
+@c 2004, 2005, 2006 Free Software Foundation, Inc.
@c See the file elisp.texi for copying conditions.
@setfilename ../info/windows
@node Windows, Frames, Buffers, Top
* Selecting Windows:: The selected window is the one that you edit in.
* Cyclic Window Ordering:: Moving around the existing windows.
* Buffers and Windows:: Each window displays the contents of a buffer.
-* Displaying Buffers:: Higher-lever functions for displaying a buffer
+* Displaying Buffers:: Higher-level functions for displaying a buffer
and choosing a window for it.
* Choosing Window:: How to choose a window for displaying a buffer.
* Window Point:: Each window has its own location of point.
* Size of Window:: Accessing the size of a window.
* Resizing Windows:: Changing the size of a window.
* Coordinates and Windows:: Converting coordinates to windows.
+* Window Tree:: The layout and sizes of all windows in a frame.
* Window Configurations:: Saving and restoring the state of the screen.
* Window Hooks:: Hooks for scrolling, window size changes,
redisplay going past a certain point,
In each frame, at any time, one and only one window is designated as
@dfn{selected within the frame}. The frame's cursor appears in that
-window. At any time, one frame is the selected frame; and the window
-selected within that frame is @dfn{the selected window}. The selected
-window's buffer is usually the current buffer (except when
+window, but the other windows have ``non-selected'' cursors, normally
+less visible. At any time, one frame is the selected frame; and the
+window selected within that frame is @dfn{the selected window}. The
+selected window's buffer is usually the current buffer (except when
@code{set-buffer} has been used). @xref{Current Buffer}.
+@defvar cursor-in-non-selected-windows
+If this variable is @code{nil}, Emacs displays only one cursor,
+in the selected window. Other windows have no cursor at all.
+@end defvar
+
For practical purposes, a window exists only while it is displayed in
a frame. Once removed from the frame, the window is effectively deleted
and should not be used, @emph{even though there may still be references
@item
how recently the window was selected
+
+@item
+fringe settings
+
+@item
+display margins
+
+@item
+scroll-bar settings
@end itemize
@cindex multiple windows
@end smallexample
Normally, Emacs indicates the border between two side-by-side windows
-with a scroll bar (@pxref{Window Frame Parameters,Scroll Bars}) or @samp{|}
+with a scroll bar (@pxref{Layout Parameters,Scroll Bars}) or @samp{|}
characters. The display table can specify alternative border
characters; see @ref{Display Tables}.
@end deffn
other, leaving the upper of the two windows selected, with @var{size}
lines. (If @var{size} is negative, then the lower of the two windows
gets @minus{} @var{size} lines and the upper window gets the rest, but
-the upper window is still the one selected.)
+the upper window is still the one selected.) However, if
+@code{split-window-keep-point} (see below) is @code{nil}, then either
+window can be selected.
+
+In other respects, this function is similar to @code{split-window}.
+In particular, the upper window is the original one and the return
+value is the new, lower window.
@end deffn
+@defopt split-window-keep-point
+If this variable is non-@code{nil} (the default), then
+@code{split-window-vertically} behaves as described above.
+
+If it is @code{nil}, then @code{split-window-vertically} adjusts point
+in each of the two windows to avoid scrolling. (This is useful on
+slow terminals.) It selects whichever window contains the screen line
+that point was previously on.
+
+This variable only affects the behavior of @code{split-window-vertically}.
+It has no effect on the other functions described here.
+@end defopt
+
@deffn Command split-window-horizontally &optional size
This function splits the selected window into two windows
-side-by-side, leaving the selected window with @var{size} columns.
+side-by-side, leaving the selected window on the left with @var{size}
+columns. If @var{size} is negative, the rightmost window gets
+@minus{} @var{size} columns, but the leftmost window still remains
+selected.
This function is basically an interface to @code{split-window}.
You could define a simplified version of the function like this:
This function returns non-@code{nil} if there is only one window. The
argument @var{no-mini}, if non-@code{nil}, means don't count the
minibuffer even if it is active; otherwise, the minibuffer window is
-included, if active, in the total number of windows, which is compared
-against one.
+counted when it is active.
The argument @var{all-frames} specifies which frames to consider. Here
are the possible values and their meanings:
The return value is @code{nil}.
@end deffn
-@deffn Command delete-windows-on buffer &optional frame
-This function deletes all windows showing @var{buffer}. If there are
-no windows showing @var{buffer}, it does nothing.
+@deffn Command delete-windows-on buffer-or-name &optional frame
+This function deletes all windows showing @var{buffer-or-name}. If
+there are no windows showing @var{buffer-or-name}, it does nothing.
+@var{buffer-or-name} must be a buffer or the name of an existing
+buffer.
@code{delete-windows-on} operates frame by frame. If a frame has
several windows showing different buffers, then those showing
-@var{buffer} are removed, and the others expand to fill the space. If
-all windows in some frame are showing @var{buffer} (including the case
-where there is only one window), then the frame reverts to having a
-single window showing another buffer chosen with @code{other-buffer}.
-@xref{The Buffer List}.
+@var{buffer-or-name} are removed, and the others expand to fill the
+space. If all windows in some frame are showing @var{buffer-or-name}
+(including the case where there is only one window), then the frame
+winds up with a single window showing another buffer chosen with
+@code{other-buffer}. @xref{The Buffer List}.
The argument @var{frame} controls which frames to operate on. This
function does not use it in quite the same way as the other functions
which the cursor appears and to which many commands apply.
@end defun
-@defun select-window window
+@defun select-window window &optional norecord
This function makes @var{window} the selected window. The cursor then
-appears in @var{window} (on redisplay). The buffer being displayed in
-@var{window} is immediately designated the current buffer.
+appears in @var{window} (on redisplay). Unless @var{window} was
+already selected, @code{select-window} makes @var{window}'s buffer the
+current buffer.
+
+Normally @var{window}'s selected buffer is moved to the front of the
+buffer list, but if @var{norecord} is non-@code{nil}, the buffer list
+order is unchanged.
The return value is @var{window}.
@end defun
@defmac save-selected-window forms@dots{}
-This macro records the selected window, executes @var{forms}
-in sequence, then restores the earlier selected window (unless that
-window is no longer alive).
-
-This macro does not save or restore anything about the sizes, arrangement
-or contents of windows; therefore, if the @var{forms} change them,
-the change persists.
-
-Each frame, at any time, has a window selected within the frame. This
-macro saves only @emph{the} selected window; it does not save anything
-about other frames. If the @var{forms} select some other frame and
-alter the window selected within it, the change persists.
+This macro records the selected frame, as well as the selected window
+of each frame, executes @var{forms} in sequence, then restores the
+earlier selected frame and windows. It also saves and restores the
+current buffer. It returns the value of the last form in @var{forms}.
+
+This macro does not save or restore anything about the sizes,
+arrangement or contents of windows; therefore, if the @var{forms}
+change them, the change persists. If the previously selected window
+of some frame is no longer live at the time of exit from @var{forms},
+that frame's selected window is left alone. If the previously
+selected window is no longer live, then whatever window is selected at
+the end of @var{forms} remains selected.
+@end defmac
+
+@defmac with-selected-window window forms@dots{}
+This macro selects @var{window} (without changing the buffer list),
+executes @var{forms} in sequence, then restores the previously
+selected window and current buffer. It is just like
+@code{save-selected-window}, except that it explicitly selects
+@var{window}, also without altering the buffer list sequence.
@end defmac
@cindex finding windows
The following functions choose one of the windows on the screen,
offering various criteria for the choice.
-@defun get-lru-window &optional frame
+@defun get-lru-window &optional frame dedicated
This function returns the window least recently ``used'' (that is,
-selected). The selected window is always the most recently used window.
+selected). If any full-width windows are present, it only considers
+these. The selected window is always the most recently used window.
The selected window can be the least recently used window if it is the
only window. A newly created window becomes the least recently used
-window until it is selected. A minibuffer window is never a candidate.
+window until it is selected. A minibuffer window is never a
+candidate. Dedicated windows are never candidates unless the
+@var{dedicated} argument is non-@code{nil}, so if all
+existing windows are dedicated, the value is @code{nil}.
The argument @var{frame} controls which windows are considered.
@end itemize
@end defun
-@defun get-largest-window &optional frame
+@defun get-largest-window &optional frame dedicated
This function returns the window with the largest area (height times
width). If there are no side-by-side windows, then this is the window
with the most lines. A minibuffer window is never a candidate.
+Dedicated windows are never candidates unless the
+@var{dedicated} argument is non-@code{nil}, so if all existing windows
+are dedicated, the value is @code{nil}.
-If there are two windows of the same size, then the function returns
-the window that is first in the cyclic ordering of windows (see
-following section), starting from the selected window.
+If there are two candidate windows of the same size, this function
+prefers the one that comes first in the cyclic ordering of windows
+(see following section), starting from the selected window.
The argument @var{frame} controls which set of windows to
consider. See @code{get-lru-window}, above.
@defun get-window-with-predicate predicate &optional minibuf all-frames default
This function returns a window satisfying @var{predicate}. It cycles
through all visible windows using @code{walk-windows} (@pxref{Cyclic
-Window Ordering}), calling @var{predicate} on each one one of them
+Window Ordering}), calling @var{predicate} on each one of them
with that window as its argument. The function returns the first
window for which @var{predicate} returns a non-@code{nil} value; if
that never happens, it returns @var{default}.
@table @asis
@item @code{nil}
Consider all the windows in @var{window}'s frame, plus the minibuffer
-used by that frame even if it lies in some other frame.
+used by that frame even if it lies in some other frame. If the
+minibuffer counts (as determined by @var{minibuf}), then all windows on
+all frames that share that minibuffer count too.
@item @code{t}
Consider all windows in all existing frames.
@item 0
Consider all windows in all visible or iconified frames.
+@item a frame
+Consider all windows on that frame.
+
@item anything else
Consider precisely the windows in @var{window}'s frame, and no others.
@end table
@c Emacs 19 feature
@defun walk-windows proc &optional minibuf all-frames
-This function cycles through all windows, calling @code{proc}
-once for each window with the window as its sole argument.
+This function cycles through all windows. It calls the function
+@code{proc} once for each window, with the window as its sole
+argument.
The optional arguments @var{minibuf} and @var{all-frames} specify the
set of windows to include in the scan. See @code{next-window}, above,
@defun window-list &optional frame minibuf window
This function returns a list of the windows on @var{frame}, starting
-with @var{window}. If @var{frame} is @code{nil} or omitted, the
-selected frame is used instead; if @var{window} is @code{nil} or
-omitted, the selected window is used instead.
-
-The value of @var{minibuf} determines if the minibuffer window will be
-included in the result list. If @var{minibuf} is @code{t}, the
-minibuffer window will be included, even if it isn't active. If
-@var{minibuf} is @code{nil} or omitted, the minibuffer window will
-only be included in the list if it is active. If @var{minibuf} is
-neither @code{nil} nor @code{t}, the minibuffer window is not
-included, whether or not it is active.
+with @var{window}. If @var{frame} is @code{nil} or omitted,
+@code{window-list} uses the selected frame instead; if @var{window} is
+@code{nil} or omitted, it uses the selected window.
+
+The value of @var{minibuf} determines if the minibuffer window is
+included in the result list. If @var{minibuf} is @code{t}, the result
+always includes the minibuffer window. If @var{minibuf} is @code{nil}
+or omitted, that includes the minibuffer window if it is active. If
+@var{minibuf} is neither @code{nil} nor @code{t}, the result never
+includes the minibuffer window.
@end defun
@node Buffers and Windows
employ heuristics in choosing or creating a window; use these functions
when you need complete control.
-@defun set-window-buffer window buffer-or-name
+@defun set-window-buffer window buffer-or-name &optional keep-margins
This function makes @var{window} display @var{buffer-or-name} as its
-contents. It returns @code{nil}. This is the fundamental primitive
-for changing which buffer is displayed in a window, and all ways
-of doing that call this function.
+contents. It returns @code{nil}. @var{buffer-or-name} must be a
+buffer, or the name of an existing buffer. This is the fundamental
+primitive for changing which buffer is displayed in a window, and all
+ways of doing that call this function.
@example
@group
@result{} nil
@end group
@end example
+
+Normally, displaying @var{buffer} in @var{window} resets the window's
+display margins, fringe widths, scroll bar settings, and position
+based on the local variables of @var{buffer}. However, if
+@var{keep-margins} is non-@code{nil}, the display margins and fringe
+widths of @var{window} remain unchanged. @xref{Fringes}.
@end defun
+@defvar buffer-display-count
+This buffer-local variable records the number of times a buffer is
+displayed in a window. It is incremented each time
+@code{set-window-buffer} is called for the buffer.
+@end defvar
+
@defun window-buffer &optional window
This function returns the buffer that @var{window} is displaying. If
@var{window} is omitted, this function returns the buffer for the
like the single optional argument of @code{get-buffer-window}. Perhaps
we should change @code{get-buffer-window} in the future to make it
compatible with the other functions.
-
-The argument @var{all-frames} controls which windows to consider.
-
-@itemize @bullet
-@item
-If it is @code{nil}, consider windows on the selected frame.
-@item
-If it is @code{t}, consider windows on all frames.
-@item
-If it is @code{visible}, consider windows on all visible frames.
-@item
-If it is 0, consider windows on all visible or iconified frames.
-@item
-If it is a frame, consider windows on that frame.
-@end itemize
@end defun
@defvar buffer-display-time
If @var{buffer-or-name} does not identify an existing buffer, then a new
buffer by that name is created. The major mode for the new buffer is
set according to the variable @code{default-major-mode}. @xref{Auto
-Major Mode}.
+Major Mode}. If @var{buffer-or-name} is @code{nil},
+@code{switch-to-buffer} chooses a buffer using @code{other-buffer}.
Normally the specified buffer is put at the front of the buffer list
(both the selected frame's buffer list and the frame-independent buffer
returns the buffer that it switched to.
@end deffn
+The next two functions are similar to @code{switch-to-buffer}, except
+for the described features.
+
@deffn Command switch-to-buffer-other-window buffer-or-name &optional norecord
This function makes @var{buffer-or-name} the current buffer and
displays it in a window not currently selected. It then selects that
switches to it in some window, preferably not the window previously
selected. The ``popped-to'' window becomes the selected window within
its frame. The return value is the buffer that was switched to.
+If @var{buffer-or-name} is @code{nil}, that means to choose some
+other buffer, but you don't specify which.
If the variable @code{pop-up-frames} is non-@code{nil},
@code{pop-to-buffer} looks for a window in any visible frame already
unless @var{norecord} is non-@code{nil}.
@end defun
-@deffn Command replace-buffer-in-windows buffer
-This function replaces @var{buffer} with some other buffer in all
-windows displaying it. The other buffer used is chosen with
+@deffn Command replace-buffer-in-windows buffer-or-name
+This function replaces @var{buffer-or-name} with some other buffer in all
+windows displaying it. It chooses the other buffer with
@code{other-buffer}. In the usual applications of this function, you
don't care which other buffer is used; you just want to make sure that
-@var{buffer} is no longer displayed.
+@var{buffer-or-name} is no longer displayed.
This function returns @code{nil}.
@end deffn
This command makes @var{buffer-or-name} appear in some window, like
@code{pop-to-buffer}, but it does not select that window and does not
make the buffer current. The identity of the selected window is
-unaltered by this function.
+unaltered by this function. @var{buffer-or-name} must be a buffer, or
+the name of an existing buffer.
If @var{not-this-window} is non-@code{nil}, it means to display the
specified buffer in a window other than the selected one, even if it is
@itemize @bullet
@item
If it is @code{nil}, consider windows on the selected frame.
+(Actually, the last non-minibuffer frame.)
@item
If it is @code{t}, consider windows on all frames.
@item
@end defopt
@c Emacs 19 feature
-@defvar pop-up-frame-function
+@defopt pop-up-frame-function
This variable specifies how to make a new frame if @code{pop-up-frames}
is non-@code{nil}.
function, which should return a frame. The default value of the
variable is a function that creates a frame using parameters from
@code{pop-up-frame-alist}.
-@end defvar
+@end defopt
@defopt pop-up-frame-alist
This variable holds an alist specifying frame parameters used when
By default, special display means to give the buffer a dedicated frame.
If an element is a list, instead of a string, then the @sc{car} of the
-list is the buffer name, and the rest of the list says how to create the
-frame. There are two possibilities for the rest of the list. It can be
-an alist, specifying frame parameters, or it can contain a function and
-arguments to give to it. (The function's first argument is always the
-buffer to be displayed; the arguments from the list come after that.)
+list is the buffer name, and the rest of the list says how to create
+the frame. There are two possibilities for the rest of the list (its
+@sc{cdr}). It can be an alist, specifying frame parameters, or it can
+contain a function and arguments to give to it. (The function's first
+argument is always the buffer to be displayed; the arguments from the
+list come after that.)
+
+For example:
+
+@example
+(("myfile" (minibuffer) (menu-bar-lines . 0)))
+@end example
+
+@noindent
+specifies to display a buffer named @samp{myfile} in a dedicated frame
+with specified @code{minibuffer} and @code{menu-bar-lines} parameters.
+
+The list of frame parameters can also use the phony frame parameters
+@code{same-frame} and @code{same-window}. If the specified frame
+parameters include @code{(same-window . @var{value})} and @var{value}
+is non-@code{nil}, that means to display the buffer in the current
+selected window. Otherwise, if they include @code{(same-frame .
+@var{value})} and @var{value} is non-@code{nil}, that means to display
+the buffer in a new window in the currently selected frame.
@end defopt
@defopt special-display-regexps
create the frame. See above, under @code{special-display-buffer-names}.
@end defopt
+@defun special-display-p buffer-name
+This function returns non-@code{nil} if displaying a buffer
+named @var{buffer-name} with @code{display-buffer} would
+create a special frame. The value is @code{t} if it would
+use the default frame parameters, or else the specified list
+of frame parameters.
+@end defun
+
@defvar special-display-function
This variable holds the function to call to display a buffer specially.
It receives the buffer as an argument, and should return the window in
@code{special-display-popup-frame}.
@end defvar
-@defun special-display-popup-frame buffer &rest args
+@defun special-display-popup-frame buffer &optional args
This function makes @var{buffer} visible in a frame of its own. If
@var{buffer} is already displayed in a window in some frame, it makes
the frame visible and raises it, to use that window. Otherwise, it
-creates a frame that will be dedicated to @var{buffer}.
+creates a frame that will be dedicated to @var{buffer}. This
+function returns the window it used.
If @var{args} is an alist, it specifies frame parameters for the new
frame.
@end defun
@defopt special-display-frame-alist
+@anchor{Definition of special-display-frame-alist}
This variable holds frame parameters for
@code{special-display-popup-frame} to use when it creates a frame.
@end defopt
buffer by switching to it in the selected window.
@end defopt
+@defun same-window-p buffer-name
+This function returns @code{t} if displaying a buffer
+named @var{buffer-name} with @code{display-buffer} would
+put it in the selected window.
+@end defun
+
@c Emacs 19 feature
@defvar display-buffer-function
This variable is the most flexible way to customize the behavior of
@code{display-buffer}. If it is non-@code{nil}, it should be a function
that @code{display-buffer} calls to do the work. The function should
-accept two arguments, the same two arguments that @code{display-buffer}
+accept two arguments, the first two arguments that @code{display-buffer}
received. It should choose or create a window, display the specified
-buffer, and then return the window.
+buffer in it, and then return the window.
This hook takes precedence over all the other options and hooks
described above.
other buffer.
@defun window-dedicated-p window
-This function returns @code{t} if @var{window} is marked as dedicated;
-otherwise @code{nil}.
+This function returns non-@code{nil} if @var{window} is marked as
+dedicated; otherwise @code{nil}.
@end defun
@defun set-window-dedicated-p window flag
@item
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.
+@end itemize
-@item
+@noindent
@xref{Positions}, for more details on buffer positions.
-@end itemize
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
@defun set-window-point window position
This function positions point in @var{window} at position
-@var{position} in @var{window}'s buffer.
+@var{position} in @var{window}'s buffer. It returns @var{position}.
+
+If @var{window} is selected, and its buffer is current,
+this simply does @code{goto-char}.
@end defun
@node Window Start
redisplay.
For a realistic example of using @code{window-start}, see the
-description of @code{count-lines} in @ref{Text Lines}.
+description of @code{count-lines}. @xref{Definition of count-lines}.
@end defun
@defun window-end &optional window update
@end defun
@defun pos-visible-in-window-p &optional position window partially
-This function returns @code{t} if @var{position} is within the range of
-text currently visible on the screen in @var{window}. It returns
-@code{nil} if @var{position} is scrolled vertically or horizontally out
-of view. Locations that are partially obscured are not considered
+This function returns non-@code{nil} if @var{position} is within the
+range of text currently visible on the screen in @var{window}. It
+returns @code{nil} if @var{position} is scrolled vertically out of
+view. Locations that are partially obscured are not considered
visible unless @var{partially} is non-@code{nil}. The argument
@var{position} defaults to the current position of point in
@var{window}; @var{window}, to the selected window.
+The @code{pos-visible-in-window-p} function considers only vertical
+scrolling. If @var{position} is out of view only because @var{window}
+has been scrolled horizontally, @code{pos-visible-in-window-p} returns
+non-@code{nil} anyway. @xref{Horizontal Scrolling}.
+
+If @var{position} is visible, @code{pos-visible-in-window-p} returns
+@code{t} if @var{partially} is @code{nil}; if @var{partially} is
+non-@code{nil}, it returns a list of the form @code{(@var{x} @var{y}
+@var{partial})}, where @var{x} and @var{y} are the pixel coordinates
+relative to the top left corner of the window, and @var{partial} is
+@code{nil} if the character after @var{position} is fully visible;
+otherwise it is a cons @code{(@var{rtop} . @var{rbot})} where the
+@var{rtop} and @var{rbot} specify the number of invisible pixels at
+the top and bottom of the row at @var{position}.
+
Here is an example:
@example
@group
+;; @r{If point is off the screen now, recenter it now.}
(or (pos-visible-in-window-p
(point) (selected-window))
(recenter 0))
@cindex textual scrolling
@cindex scrolling textually
- @dfn{Textual scrolling} means moving the text up or down though a
+ @dfn{Textual scrolling} means moving the text up or down through a
window. It works by changing the value of the window's display-start
location. It may also change the value of @code{window-point} to keep
point on the screen.
buffer is different from the buffer that is displayed in the selected
window. @xref{Current Buffer}.
+ If the window contains a row which is taller than the height of the
+window (for example in the presense of a large image), the scroll
+functions will adjust the window vscroll to scroll the partially
+visible row. To disable this feature, Lisp code may bind the variable
+`auto-window-vscroll' to @code{nil} (@pxref{Vertical Scrolling}).
+
@deffn Command scroll-up &optional count
This function scrolls the text in the selected window upward
@var{count} lines. If @var{count} is negative, scrolling is actually
is @code{next-screen-context-lines} lines less than the usable height of
the window (not counting its mode line).
-@code{scroll-up} returns @code{nil}.
+@code{scroll-up} returns @code{nil}, unless it gets an error
+because it can't scroll any further.
@end deffn
@deffn Command scroll-down &optional count
is @code{next-screen-context-lines} lines less than the usable height of
the window (not counting its mode line).
-@code{scroll-down} returns @code{nil}.
+@code{scroll-down} returns @code{nil}, unless it gets an error because
+it can't scroll any further.
@end deffn
@deffn Command scroll-other-window &optional count
the one at the top left corner. You can specify a different window to
scroll, when the minibuffer is selected, by setting the variable
@code{minibuffer-scroll-window}. This variable has no effect when any
-other window is selected. @xref{Minibuffer Misc}.
+other window is selected. When it is non-@code{nil} and the
+minibuffer is selected, it takes precedence over
+@code{other-window-scroll-buffer}. @xref{Definition of
+minibuffer-scroll-window}.
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,
@end defopt
@defopt scroll-preserve-screen-position
-If this option is non-@code{nil}, the scroll functions move point so
-that the vertical position of the cursor is unchanged, when that is
-possible.
+If this option is @code{t}, scrolling which would move the current
+point position out of the window chooses the new position of point
+so that the vertical position of the cursor is unchanged, if possible.
+
+If it is non-@code{nil} and not @code{t}, then the scrolling functions
+always preserve the vertical position of point, if possible.
@end defopt
@defopt next-screen-context-lines
@dfn{Vertical fractional scrolling} means shifting the image in the
window up or down by a specified multiple or fraction of a line.
-Starting in Emacs 21, each window has a @dfn{vertical scroll position},
+Each window has a @dfn{vertical scroll position},
which is a number, never less than zero. It specifies how far to raise
the contents of the window. Raising the window contents generally makes
all or part of some lines disappear off the top, and all or part of some
line whose height is very short off the screen, while a value of 3.3
could scroll just part of the way through a tall line or an image.
-@defun window-vscroll &optional window
+@defun window-vscroll &optional window pixels-p
This function returns the current vertical scroll position of
-@var{window}, If @var{window} is @code{nil}, the selected window is
-used.
+@var{window}. If @var{window} is @code{nil}, the selected window is
+used. If @var{pixels-p} is non-@code{nil}, the return value is
+measured in pixels, rather than in units of the normal line height.
@example
@group
@end example
@end defun
-@defun set-window-vscroll window lines
+@defun set-window-vscroll window lines &optional pixels-p
This function sets @var{window}'s vertical scroll position to
@var{lines}. The argument @var{lines} should be zero or positive; if
not, it is taken as zero.
@result{} 1.13
@end group
@end example
+
+If @var{pixels-p} is non-@code{nil}, @var{lines} specifies a number of
+pixels. In this case, the return value is @var{lines}.
@end defun
+@defvar auto-window-vscroll
+If this variable is non-@code{nil}, the line-move, scroll-up, and
+scroll-down functions will automatically modify the window vscroll to
+scroll through display rows that are taller that the height of the
+window, for example in the presense of large images.
+@end defvar
+
@node Horizontal Scrolling
@section Horizontal Scrolling
@cindex horizontal scrolling
left edge.
@vindex auto-hscroll-mode
- In Emacs 21, redisplay automatically alters the horizontal scrolling
-of a window as necessary to ensure that point is always visible, if
-@code{auto-hscroll-mode} is set. However, you can still set the
-horizontal scrolling value explicitly. The value you specify serves as
-a lower bound for automatic scrolling, i.e. automatic scrolling
-will not scroll a window to a column less than the specified one.
-
-@deffn Command scroll-left &optional count
+ If @code{auto-hscroll-mode} is set, redisplay automatically alters
+the horizontal scrolling of a window as necessary to ensure that point
+is always visible. However, you can still set the horizontal
+scrolling value explicitly. The value you specify serves as a lower
+bound for automatic scrolling, i.e. automatic scrolling will not
+scroll a window to a column less than the specified one.
+
+@deffn Command scroll-left &optional count set-minimum
This function scrolls the selected window @var{count} columns to the
left (or to the right if @var{count} is negative). The default
for @var{count} is the window width, minus 2.
-The return value is the total amount of leftward horizontal scrolling in
-effect after the change---just like the value returned by
-@code{window-hscroll} (below).
-@end deffn
-
-@deffn Command scroll-right &optional count
-This function scrolls the selected window @var{count} columns to the
-right (or to the left if @var{count} is negative). The default
-for @var{count} is the window width, minus 2.
-
The return value is the total amount of leftward horizontal scrolling in
effect after the change---just like the value returned by
@code{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.
+
+If @var{set-minimum} is non-@code{nil}, the new scroll amount becomes
+the lower bound for automatic scrolling; that is, automatic scrolling
+will not scroll a window to a column less than the value returned by
+this function. Interactive calls pass non-@code{nil} for
+@var{set-minimum}.
+@end deffn
+
+@deffn Command scroll-right &optional count set-minimum
+This function scrolls the selected window @var{count} columns to the
+right (or to the left if @var{count} is negative). The default
+for @var{count} is the window width, minus 2. Aside from the direction
+of scrolling, this works just like @code{scroll-left}.
@end deffn
@defun window-hscroll &optional window
@end defun
@defun set-window-hscroll window columns
-This function sets the number of columns from the left margin that
-@var{window} is scrolled from the value of @var{columns}. The argument
-@var{columns} should be zero or positive; if not, it is taken as zero.
-Fractional values of @var{columns} are not supported at present.
+This function sets horizontal scrolling of @var{window}. The value of
+@var{columns} specifies the amount of scrolling, in terms of columns
+from the left margin. The argument @var{columns} should be zero or
+positive; if not, it is taken as zero. Fractional values of
+@var{columns} are not supported at present.
Note that @code{set-window-hscroll} may appear not to work if you test
it by evaluating a call with @kbd{M-:} in a simple way. What happens
@defun window-height &optional window
This function returns the number of lines in @var{window}, including
its mode line and header line, if any. If @var{window} fills its
-entire frame except for the echo area, and there is no tool bar, this
-is typically one less than the value of @code{frame-height} on that
-frame.
+entire frame except for the echo area, this is typically one less than
+the value of @code{frame-height} on that frame.
If @var{window} is @code{nil}, the function uses the selected window.
@tindex window-body-height
@defun window-body-height &optional window
-Like @code{window-height} but the value does not include the
+Like @code{window-height} but the value does not include the
mode line (if any) or the header line (if any).
@end defun
rightmost column used by @var{window}, and @var{bottom} is one more than
the bottommost row used by @var{window} and its mode-line.
-If a window has a scroll bar, the right edge value includes the width of
-the scroll bar. Otherwise, if the window has a neighbor on the right,
-its right edge value includes the width of the separator line between
-the window and that neighbor. Since the width of the window does not
-include this separator, the width does not usually equal the difference
-between the right and left edges.
+The edges include the space used by the window's scroll bar, display
+margins, fringes, header line, and mode line, if it has them. Also,
+if the window has a neighbor on the right, its right edge value
+includes the width of the separator line between the window and that
+neighbor. Since the width of the window does not include this
+separator, the width does not usually equal the difference between the
+right and left edges.
+@end defun
-Here is the result obtained on a typical 24-line terminal with just one
-window:
+@defun window-inside-edges &optional window
+This is similar to @code{window-edges}, but the edge values
+it returns include only the text area of the window. They
+do not include the header line, mode line, scroll bar or
+vertical separator, fringes, or display margins.
+@end defun
+
+Here are the results obtained on a typical 24-line terminal with just
+one window, with menu bar enabled:
@example
@group
(window-edges (selected-window))
- @result{} (0 0 80 23)
+ @result{} (0 1 80 23)
+@end group
+@group
+(window-inside-edges (selected-window))
+ @result{} (0 1 80 22)
@end group
@end example
@noindent
The bottom edge is at line 23 because the last line is the echo area.
-
-If @var{window} is at the upper left corner of its frame, then
-@var{bottom} is the same as the value of @code{(window-height)},
-@var{right} is almost the same as the value of @code{(window-width)},
-and @var{top} and @var{left} are zero. For example, the edges of the
-following window are @w{@samp{0 0 8 5}}. Assuming that the frame has
-more than 8 columns, the last column of the window (column 7) holds a
-border rather than text. The last row (row 4) holds the mode line,
-shown here with @samp{xxxxxxxxx}.
+The bottom inside edge is at line 22, which is the window's mode line.
+
+If @var{window} is at the upper left corner of its frame, and there is
+no menu bar, then @var{bottom} returned by @code{window-edges} is the
+same as the value of @code{(window-height)}, @var{right} is almost the
+same as the value of @code{(window-width)}, and @var{top} and
+@var{left} are zero. For example, the edges of the following window
+are @w{@samp{0 0 8 5}}. Assuming that the frame has more than 8
+columns, the last column of the window (column 7) holds a border
+rather than text. The last row (row 4) holds the mode line, shown
+here with @samp{xxxxxxxxx}.
@example
@group
In the following example, let's suppose that the frame is 7
columns wide. Then the edges of the left window are @w{@samp{0 0 4 3}}
-and the edges of the right window are @w{@samp{4 0 8 3}}.
+and the edges of the right window are @w{@samp{4 0 7 3}}.
+The inside edges of the left window are @w{@samp{0 0 3 2}},
+and the inside edges of the right window are @w{@samp{4 0 7 2}},
@example
@group
0 34 7
@end group
@end example
+
+@defun window-pixel-edges &optional window
+This function is like @code{window-edges} except that, on a graphical
+display, the edge values are measured in pixels instead of in
+character lines and columns.
+@end defun
+
+@defun window-inside-pixel-edges &optional window
+This function is like @code{window-inside-edges} except that, on a
+graphical display, the edge values are measured in pixels instead of
+in character lines and columns.
@end defun
@node Resizing Windows
@example
@group
(defun enlarge-window-horizontally (columns)
+ (interactive "p")
(enlarge-window columns t))
@end group
@end example
@example
@group
(defun shrink-window-horizontally (columns)
+ (interactive "p")
(shrink-window columns t))
@end group
@end example
@end deffn
+@defun adjust-window-trailing-edge window delta horizontal
+This function makes the selected window @var{delta} lines taller or
+@var{delta} columns wider, by moving the bottom or right edge. This
+function does not delete other windows; if it cannot make the
+requested size adjustment, it signals an error. On success, this
+function returns @code{nil}.
+@end defun
+
+@defun fit-window-to-buffer &optional window max-height min-height
+This function makes @var{window} the right height to display its
+contents exactly. If @var{window} is omitted or @code{nil}, it uses
+the selected window.
+
+The argument @var{max-height} specifies the maximum height the window
+is allowed to be; @code{nil} means use the frame height. The argument
+@var{min-height} specifies the minimum height for the window;
+@code{nil} means use @code{window-min-height}. All these height
+values include the mode-line and/or header-line.
+@end defun
+
@deffn Command shrink-window-if-larger-than-buffer &optional window
-This command shrinks @var{window} to be as small as possible while still
-showing the full contents of its buffer---but not less than
-@code{window-min-height} lines. If @var{window} is not given,
-it defaults to the selected window.
+This command shrinks @var{window} vertically to be as small as
+possible while still showing the full contents of its buffer---but not
+less than @code{window-min-height} lines. If @var{window} is not
+given, it defaults to the selected window.
However, the command does nothing if the window is already too small to
display the whole text of the buffer, or if part of the contents are
currently scrolled off screen, or if the window is not the full width of
its frame, or if the window is the only window in its frame.
+
+This command returns non-@code{nil} if it actually shrank the window
+and @code{nil} otherwise.
@end deffn
@tindex window-size-fixed
If this variable is non-@code{nil}, in any given buffer,
then the size of any window displaying the buffer remains fixed
unless you explicitly change it or Emacs has no other choice.
-(This feature is new in Emacs 21.)
If the value is @code{height}, then only the window's height is fixed;
if the value is @code{width}, then only the window's width is fixed.
Any other non-@code{nil} value fixes both the width and the height.
-The usual way to use this variable is to give it a buffer-local value in
-a particular buffer. That way, the windows (but usually there is only
-one) displaying that buffer have fixed size.
+This variable automatically becomes buffer-local when set.
Explicit size-change functions such as @code{enlarge-window}
get an error if they would have to change a window size which is fixed.
have a scroll bar; positions in a scroll bar are considered outside the
window for these purposes.
+@item left-fringe
+@itemx right-fringe
+The coordinates are in the left or right fringe of the window.
+
+@item left-margin
+@itemx right-margin
+The coordinates are in the left or right margin of the window.
+
@item nil
The coordinates are not in any part of @var{window}.
@end table
argument because it always uses the frame that @var{window} is on.
@end defun
+@node Window Tree
+@section The Window Tree
+@cindex window tree
+
+ A @dfn{window tree} specifies the layout, size, and relationship
+between all windows in one frame.
+
+@defun window-tree &optional frame
+This function returns the window tree for frame @var{frame}.
+If @var{frame} is omitted, the selected frame is used.
+
+The return value is a list of the form @code{(@var{root} @var{mini})},
+where @var{root} represents the window tree of the frame's
+root window, and @var{mini} is the frame's minibuffer window.
+
+If the root window is not split, @var{root} is the root window itself.
+Otherwise, @var{root} is a list @code{(@var{dir} @var{edges} @var{w1}
+@var{w2} ...)} where @var{dir} is @code{nil} for a horizontal split,
+and @code{t} for a vertical split, @var{edges} gives the combined size and
+position of the subwindows in the split, and the rest of the elements
+are the subwindows in the split. Each of the subwindows may again be
+a window or a list representing a window split, and so on. The
+@var{edges} element is a list @code{(@var{left}@var{ top}@var{ right}@var{ bottom})}
+similar to the value returned by @code{window-edges}.
+@end defun
+
@node Window Configurations
@section Window Configurations
@cindex window configurations
A @dfn{window configuration} records the entire layout of one
frame---all windows, their sizes, which buffers they contain, what
part of each buffer is displayed, and the values of point and the
-mark. It also includes the values of @code{window-min-height},
+mark; also their fringes, margins, and scroll bar settings. It also
+includes the values of @code{window-min-height},
@code{window-min-width} and @code{minibuffer-scroll-window}. An
exception is made for point in the selected window for the current
buffer; its value is not saved in the window configuration.
If the frame which @var{configuration} was saved from is dead, all this
function does is restore the three variables @code{window-min-height},
-@code{window-min-width} and @code{minibuffer-scroll-window}.
+@code{window-min-width} and @code{minibuffer-scroll-window}. In this
+case, the function returns @code{nil}. Otherwise, it returns @code{t}.
Here is a way of using this function to get the same effect
as @code{save-window-excursion}:
@defspec save-window-excursion forms@dots{}
This special form records the window configuration, executes @var{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 @code{save-excursion} also, if you wish to preserve that.
+configuration includes, for each window, 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 @code{save-excursion} also, if you wish to
+preserve that.
-Don't use this construct when @code{save-selected-window} is all you need.
+Don't use this construct when @code{save-selected-window} is sufficient.
Exit from @code{save-window-excursion} always triggers execution of the
@code{window-size-change-functions}. (It doesn't know how to tell
saved point or mark.
@end defun
- 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. See the file @file{winner.el} for some more
-operations on windows configurations.
+@defun window-configuration-frame config
+This function returns the frame for which the window configuration
+@var{config} was made.
+@end defun
+
+ Other primitives to look inside of window configurations would make
+sense, but are not implemented because we did not need them. See the
+file @file{winner.el} for some more operations on windows
+configurations.
@node Window Hooks
@section Hooks for Window Scrolling and Changes
There are three actions that can change this: scrolling the window,
switching buffers in the window, and changing the size of the window.
The first two actions run @code{window-scroll-functions}; the last runs
-@code{window-size-change-functions}. The paradigmatic use of these
-hooks is in the implementation of Lazy Lock mode; see @ref{Support
-Modes, Lazy Lock, Font Lock Support Modes, emacs, The GNU Emacs Manual}.
+@code{window-size-change-functions}.
@defvar window-scroll-functions
This variable holds a list of functions that Emacs should call before
@defun window-redisplay-end-trigger &optional window
This function returns @var{window}'s current end trigger position.
+If @var{window} is @code{nil} or omitted, it uses the selected window.
@end defun
@defvar window-configuration-change-hook
window. The frame whose window configuration has changed is the
selected frame when this hook runs.
@end defvar
+
+@ignore
+ arch-tag: 3f6c36e8-df49-4986-b757-417feed88be3
+@end ignore