@cindex window size
@cindex size of window
-Emacs windows are rectangular. The structure of a live window can be
-roughly sketched as follows:
+ The following schematic shows the structure of a live window:
@smallexample
@group
- _________________________________________
- ^ |______________ Header Line_______________|
+ _________________________________________
+ ^ |______________ Header Line_______________|
| |LS|LF|LM| |RM|RF|RS| ^
| | | | | | | | | |
Window | | | | Text Area | | | | Window
@end smallexample
@cindex window body
+@cindex text area of a window
@cindex body of a window
-The text area constitutes the body of the window. In its most simple
-form, a window consists of its body alone. LS and RS stand for the left
-and right scroll bar (@pxref{Scroll Bars}) respectively. Only one of
-them can be present at any time. LF and RF denote the left and right
-fringe, see @ref{Fringes}. LM and RM, finally, stand for the left and
-right display margin, see @ref{Display Margins}. The header line, if
-present, is located above theses areas, the mode line below, see
-@ref{Mode Line Format}.
+ At the center of the window is the @dfn{text area}, or @dfn{body},
+where the buffer text is displayed. On each side of the text area is
+a series of vertical areas; from innermost to outermost, these are the
+left and right margins, denoted by LM and RM in the schematic
+(@pxref{Display Margins}); the left and right fringes, denoted by LF
+and RF (@pxref{Fringes}); and the left or right scroll bar, only one of
+which is present at any time, denoted by LS and RS (@pxref{Scroll
+Bars}). At the top of the window is an optional header line
+(@pxref{Header Lines}), and at the bottom of the window is the mode
+line (@pxref{Mode Line Format}).
+
+ Emacs provides several functions for finding the height and width of
+a window. Most of these functions report the values as integer
+multiples of the default character height and width. On a graphical
+display, the actual screen size of this default height and width are
+those specified by the frame's default font. Hence, if the buffer
+contains text that is displayed in a different size, the reported
+height and width of the window may differ from the actual number of
+text lines or columns displayed in it.
@cindex window height
-@cindex total window height
@cindex height of a window
@cindex total height of a window
-The @dfn{total height of a window} is specified as the total number of
-lines occupied by the window. Any mode or header line is included in a
-window's total height. For an internal window, the total height is
-calculated recursively from the total heights of its child windows.
-
@cindex window width
-@cindex total window width
@cindex width of a window
@cindex total width of a window
-The @dfn{total width of a window} denotes the total number of columns of
-the window. Any scroll bar and the column of @samp{|} characters that
-separate the window from its right sibling are included in a window's
-total width. On a window-system, fringes and display margins are
-included in a window's total width too. For an internal window, the
-total width is calculated recursively from the total widths of its child
-windows.
-
-@cindex total size of a window
-@cindex total window size
-The following function is the standard interface for getting the total
-size of any window:
-
-@defun window-total-size &optional window &optional horizontal
-This function returns the total number of lines of @var{window}. The
-argument @var{window} can denote any window and defaults to the selected
-one. If @var{window} is live, the return value includes any header or
-mode lines of @var{window}. If @var{window} is internal, the return
-value is the sum of the total heights of @var{window}'s child windows
-provided these are vertically combined and the height of @var{window}'s
-first child if they are horizontally combined.
-
- If the optional argument @var{horizontal} is non-@code{nil}, this
-function returns the total number of columns of @var{window}. If
-@var{window} is live, the return value includes any vertical divider
-column or scroll bars of @var{window}. On a window-system, the return
-value includes the space occupied by any margins and fringes of
-@var{window} too. If @var{window} is internal, the return value is the
-sum of the total widths of @var{window}'s child windows provided these
-are horizontally combined and the width of @var{window}'s first child
-otherwise.
-@end defun
-
-Alternatively, the following two functions can be used to retrieve
-either the total height or the total width of a window:
+ The @dfn{total height} of a window is the distance between the top
+and bottom of the window, including the header line (if one exists)
+and the mode line. The @dfn{total width} of a window is the distance
+between the left and right edges of the mode line. Note that the
+height of a frame is not the same as the height of its windows, since
+a frame may also contain an echo area, menu bar, and tool bar
+(@pxref{Size and Position}).
@defun window-total-height &optional window
-This function returns the total number of lines of @var{window}.
-@var{window} can be any window and defaults to the selected one. The
-return value includes @var{window}'s mode line and header line, if any.
-If @var{window} is internal the return value is the sum of heights of
-@var{window}'s child windows for a vertical combination and the height
-of @var{window}'s first child otherwise.
+This function returns the total height, in lines, of the window
+@var{window}. If @var{window} is omitted or @code{nil}, it defaults
+to the selected window. If @var{window} is an internal window, the
+return value is the total height occupied by its descendant windows.
@end defun
@defun window-total-width &optional window
-This function returns the total number of columns of @var{window}.
-@var{window} can be any window and defaults to the selected one. The
-return value includes any vertical dividers or scrollbars of
-@var{window}. On a window-system the return value also includes the
-space occupied by any margins and fringes of @var{window}. If
-@var{window} is internal, the return value is the sum of the widths of
-@var{window}'s child windows for a horizontal combination and the width
-of @var{window}'s first child otherwise.
-@end defun
-
-The total height of any window is usually less than the height of the
-window's frame, because the latter may also include the minibuffer
-window. Depending on the toolkit in use, the frame height can also
-include the menu bar and the tool bar (@pxref{Size and Position}).
-Therefore, in general it is not straightforward to compare window and
-frame heights. The following function is useful to determine whether
-there are no other windows above or below a specified window.
+This function returns the total width, in columns, of the window
+@var{window}. If @var{window} is omitted or @code{nil}, it defaults
+to the selected window. If @var{window} is internal, the return value
+is the total width occupied by its descendant windows.
+@end defun
-@cindex full-height window
-@defun window-full-height-p &optional window
-This function returns non-@code{nil} if there is no other window above
-or below @var{window} on the containing frame. More precisely, this
-function returns @code{t} if and only if the total height of
-@var{window} equals the total height of the root window (@pxref{Windows
-and Frames}) of @var{window}'s frame. The @var{window} argument may
-denote any window and defaults to the selected one.
+@defun window-total-size &optional window horizontal
+This function returns either the total height or width of the window
+@var{window}. If @var{horizontal} is omitted or @code{nil}, this is
+equivalent to calling @code{window-total-height} for @var{window};
+otherwise it is equivalent to calling @code{window-total-width} for
+@var{window}.
@end defun
@cindex full-width window
-The following function can be used to determine whether there are no
-other windows on the left or right of a specified window.
+@cindex full-height window
+ The following functions can be used to determine whether a given
+window has any adjacent windows.
+
+@defun window-full-height-p &optional window
+This function returns non-@code{nil} if @var{window} has no other
+window above or below it in its frame, i.e. its total height equals
+the total height of the root window on that frame. If @var{window} is
+omitted or @code{nil}, it defaults to the selected window.
+@end defun
@defun window-full-width-p &optional window
-This function returns non-@code{nil} if there are no other windows on
-the left or right of @var{window}; @code{nil} otherwise. More
-precisely, this function returns @code{t} if and only if the total width
-of @var{window} equals the total width of the root window
-(@pxref{Windows and Frames}) of @var{window}'s frame. The @var{window}
-argument may denote any window and defaults to the selected one.
+This function returns non-@code{nil} if @var{window} has no other
+window to the left or right in its frame, i.e. its total width equals
+that of the root window on that frame. If @var{window} is omitted or
+@code{nil}, it defaults to the selected window.
@end defun
-@cindex top line of window
-@cindex left column of window
- The windows of a frame are unambiguously characterized by the
-combination of their top line and left column within that frame.
+@cindex window position
+ The following functions can be used to determine the position of a
+window relative to the window area of its frame:
@defun window-top-line &optional window
-This function returns the top line of @var{window}. The argument
-@var{window} can denote any window and defaults to the selected one.
+This function returns the distance, in lines, between the top of
+@var{window} and the top of the frame's window area. For instance,
+the return value is 0 if there is no window above @var{window}. If
+@var{window} is omitted or @code{nil}, it defaults to the selected
+window.
@end defun
@defun window-left-column &optional window
-This function returns the left column of @var{window}. The argument
-@var{window} can denote any window and defaults to the selected one.
+This function returns the distance, in columns, between the left edge
+of @var{window} and the left edge of the frame's window area. For
+instance, the return value is 0 if there is no window to the left of
+@var{window}. If @var{window} is omitted or @code{nil}, it defaults
+to the selected window.
@end defun
-For a frame displaying one window only, that window's top line and left
-column are both zero. When a frame displays a window @var{WB} below a
-window @var{WA}, the top line of @var{WB} can be calculated by adding
-the total height of @var{WA} to the top line of @var{WA}. When a frame
-displays a window @var{WR} on the right of a window @var{WL}, the left
-column of @var{WR} can be calculated by adding the total width of
-@var{WL} to the left column of @var{WL}.
-
@cindex window body height
@cindex body height of a window
-The @dfn{body height of a window} is specified as the total number of
-lines occupied by the window's text area. Mode or header lines are not
-included in a window's body height.
-
@cindex window body width
@cindex body width of a window
-The @dfn{body width of a window} denotes the total number of columns
-occupied by the window's text area. Scroll bars or columns of @samp{|}
-characters that separate side-by-side windows are not included in a
-window's body width.
-
@cindex body size of a window
@cindex window body size
-@cindex canonical units of window/frame size
-The following functions retrieve height and width of the body of a
-live window. Note that the values these functions return are measured
-in @dfn{canonical units}, i.e.@: for the default frame's face. If the
-window shows some characters with non-default face, e.g., if the font
-of some characters is larger or smaller than the default font, the
-values returned by these functions will not match the actual number of
-lines or characters per line shown in the window. To get the actual
-number of columns and lines, move to the last character in the line
-(e.g., with @code{end-of-visual-line}) or to the last line of the
-window (e.g., with @code{window-end}), and use @code{posn-at-point} to
-find the line or column there.
-
-@defun window-body-size &optional window horizontal
-This function returns the number of lines of @var{window}'s text area.
-@var{window} must be a live window and defaults to the selected one.
-The return value does not count any mode or header line of @var{window}.
-
-Optional argument @var{horizontal} non-@code{nil} means to return the
-number of columns of @var{window}'s text area. In this case the return
-value does not include any vertical divider or scroll bar owned by
-@var{window}. On a window-system the return value does not include the
-number of columns used for @var{window}'s fringes or display margins
-either.
-@end defun
+ The @dfn{body height} of a window is the height of its text area,
+which does not include the mode or header line. Similarly, the
+@dfn{body width} is the width of the text area, which does not include
+the scroll bar, fringes, or margins.
@defun window-body-height &optional window
-This function returns the number of lines of @var{window}'s body.
-@var{window} must be a live window and defaults to the selected one.
+This function returns the body height, in lines, of the window
+@var{window}. If @var{window} is omitted or @code{nil}, it defaults
+to the selected window; otherwise it must be a live window.
-The return value does not include @var{window}'s mode line and header
-line, if any. If a line at the bottom of the window is only partially
-visible, that line is included in the return value. If you do not
-want to include a partially visible bottom line in the return value,
-use @code{window-text-height} instead.
+If there is a partially-visible line at the bottom of the text area,
+that counts as a whole line; to exclude such a partially-visible line,
+use @code{window-text-height}, below.
@end defun
@defun window-body-width &optional window
-This function returns the number of columns of @var{window}'s body.
-@var{window} must be a live window and defaults to the selected one.
-
-The return value does not include any vertical dividers or scroll bars
-owned by @var{window}. On a window-system the return value does not
-include the number of columns used for @var{window}'s fringes or
-display margins either.
+This function returns the body width, in columns, of the window
+@var{window}. If @var{window} is omitted or @code{nil}, it defaults
+to the selected window; otherwise it must be a live window.
@end defun
-The following functions have been used in earlier versions of Emacs.
-They are still supported but due to the confusing nomenclature they
-should not be used any more in future code.
-
-@defun window-height &optional window
-This function is an alias for `window-total-height', see above.
+@defun window-body-size &optional window horizontal
+This function returns the body height or body width of @var{window}.
+If @var{horizontal} is omitted or @code{nil}, it is equivalent to
+calling @code{window-body-height} for @var{window}; otherwise it is
+equivalent to calling @code{window-body-width}.
@end defun
-@defun window-width &optional window
-This function is an alias for `window-body-width', see above.
+@defun window-text-height &optional window
+This function is like @code{window-body-height}, except that any
+partially-visible line at the bottom of the text area is not counted.
@end defun
-@cindex minimum window size
- The following two options constrain the sizes of windows to a minimum
-height and width. Their values are honored when windows are split
-(@pxref{Splitting Windows}) or resized (@pxref{Resizing Windows}). Any
-request to make a window smaller than specified here will usually result
-in an error.
-
-@defopt window-min-height
-The value of this variable specifies how short a window may be. The
-value is measured in line units and has to account for any header or
-mode line. The default value for this option is @code{4}. Values less
-than @code{1} are ignored.
-@end defopt
-
-@defopt window-min-width
-The value of this variable specifies how narrow a window may be. The
-value is measured in characters and includes any margins, fringes,
-scroll bar and vertical divider column. The default value for this
-option is @code{10}. A value less than @code{2} is ignored.
-@end defopt
-
-Applications should not rebind these variables. To shrink a specific
-window to a height or width less than the one specified here, they
-should rather invoke @code{window-resize} (@pxref{Resizing Windows})
-with a non-@code{nil} @var{ignore} argument. The function
-@code{split-window} (@pxref{Splitting Windows}) can make a window
-smaller than specified here by calling it with a non-@code{nil}
-@var{size} argument. Interactively, the values specified here cannot be
-overridden.
-
- Earlier versions of Emacs could delete a window when its size dropped
-below @code{window-min-height} or @code{window-min-width}. As a rule,
-the current version of Emacs does no more delete windows by side-effect.
-The only exception to this rule are requests to resize a frame which may
-implicitly delete windows when they do not fit on the frame any more,
-see @ref{Size and Position}.
-
- The size of a window can be fixed which means that it cannot be split
-(@pxref{Splitting Windows}) or resized (@pxref{Resizing Windows}).
+ For compatibility with previous versions of Emacs,
+@code{window-height} is an alias for @code{window-body-height}, and
+@code{window-width} is an alias for @code{window-body-width}. These
+aliases are considered obsolete and will be removed in the future.
@cindex fixed-size window
+ Commands that change the size of windows (@pxref{Resizing Windows}),
+or split them (@pxref{Splitting Windows}), obey the variables
+@code{window-min-height} and @code{window-min-width}, which specify
+the smallest allowable window height and width. @xref{Change
+Window,,Deleting and Rearranging Windows, emacs, The GNU Emacs
+Manual}. They also obey the variable @code{window-size-fixed}, with
+which a window can be @dfn{fixed} in size:
+
@defvar window-size-fixed
-If this variable is non-@code{nil}, in a given buffer, then the size of
-any window displaying that buffer remains fixed unless you either
-explicitly change it or Emacs has no other choice.
+If this buffer-local variable is non-@code{nil}, the size of any
+window displaying the buffer cannot normally be changed. Deleting a
+window or changing the frame's size may still change its size, if
+there is no choice.
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.
-
-This variable automatically becomes buffer-local when set.
@end defvar
-Commands supposed to explicitly change the size of windows such as
-@code{enlarge-window} (@pxref{Resizing Windows}) get an error if they
-had to change a window size which is fixed. Other functions like
-@code{window-resize} (@pxref{Resizing Windows}) have an optional
-@var{ignore} argument which allows to change the size of fixed-size
-windows.
-
- Deleting a window or changing a frame's size may change the size of a
-fixed-size window, if there is no other alternative.
-
- The height of a vertical combination of windows cannot be changed
-when the height of all these windows is fixed. Its width cannot be
-changed if the width of at least one of these windows is fixed.
-Similarly, the width of a horizontal combination of windows cannot be
-changed when the width of all these windows is fixed. Its height cannot
-be changed if the height of at least one of these windows is fixed.
-
- The next function allows to check whether the size of an arbitrary
-window is fixed.
-
@defun window-size-fixed-p &optional window horizontal
-This function returns non-@code{nil} if @var{window}'s height is fixed.
-The argument @var{window} can be an arbitrary window and defaults to the
-selected one. Optional argument @var{horizontal} non-@code{nil} means
-return non-@code{nil} if @var{window}'s width is fixed.
+This function returns a non-@code{nil} value if @var{window}'s height
+is fixed. If @var{window} is omitted or @code{nil}, it defaults to
+the selected window. If the optional argument @var{horizontal} is
+non-@code{nil}, the return value is non-@code{nil} if @var{window}'s
+width is fixed.
-If this function returns @code{nil}, this does not necessarily mean that
-@var{window} can be resized in the desired direction. The function
-@code{window-resizable} (@pxref{Resizing Windows}) can tell that.
+A @code{nil} return value does not necessarily mean that @var{window}
+can be resized in the desired direction. To determine that, use the
+function @code{window-resizable}. @xref{Resizing Windows}.
@end defun
minimum value in the range from @var{delta} to 0 that can be used for
shrinking @var{window}.
-Optional argument @var{ignore} non-@code{nil} means ignore any
-restrictions imposed by the variables @code{window-min-height} or
-@code{window-min-width} and @code{window-size-fixed}. In this case the
-minimum height of a window is specified as the minimum number of lines
-that allow viewing any header or mode line and at least one line of the
-text area of window. The minimum width of a window includes any
-fringes, margins and the scroll bar as well as two text columns.
+Normally, the customizable variables @code{window-min-height} and
+@code{window-min-width} specify the smallest allowable size of a
+window. @xref{Change Window,,Deleting and Rearranging Windows,
+emacs, The GNU Emacs Manual}. If resizing would result in making any
+window smaller than this, this function usually signals an error.
+However, if the optional argument @var{ignore} is non-@code{nil}, this
+function ignores @code{window-min-height} and @code{window-min-width},
+as well as @code{window-size-fixed}. In that case, the minimum-height
+window consists of a header (if any), a mode line, plus a text area
+one line tall; the minimum-width window consists of any fringes,
+margins and scroll bar, plus a text area two columns wide.
If @var{ignore} denotes a window, this means to ignore restrictions for
that window only. If @var{ignore} equals the constant @code{safe}, this
right. If @var{delta} is less than zero, this moves the edge upwards or
to the left. If the edge can't be moved by @var{delta} lines or columns,
it is moved as far as possible in the desired direction but no error is
-signalled.
+signaled.
This function tries to resize windows adjacent to the edge that is
moved. Only if this is insufficient, it will also resize windows not
The optional argument @var{max-height} specifies the maximum total
height the window is allowed to be; @code{nil} means use the maximum
permissible height of a window on @var{window}'s frame. The optional
-argument @var{min-height} specifies the minimum toatl height for the
+argument @var{min-height} specifies the minimum total height for the
window; @code{nil} means use @code{window-min-height}. All these height
values include the mode line and/or header line.
divided evenly into two parts. (If there is an odd line, it is
allocated to the new window.)
-If splitting would result in making a window smaller than
-@code{window-min-height} or @code{window-min-width} (@pxref{Window
-Sizes}), this function usually signals an error. However, if @var{size}
-is non-@code{nil} and valid, a new window of the requested size is
-created. (A size value would be invalid if it assigned less than one
-line or less than two columns to the new window.)
+Normally, the customizable variables @code{window-min-height} and
+@code{window-min-width} specify the smallest allowable size of a
+window. @xref{Change Window,,Deleting and Rearranging Windows, emacs,
+The GNU Emacs Manual}. If splitting would result in making a window
+smaller than this, this function usually signals an error. However,
+if @var{size} is non-@code{nil} and valid, a new window of the
+requested size is created, provided it has enough space for a text
+area one line tall and/or two columns wide.
Optional third argument @var{side} @code{nil} (or @code{below})
specifies that the new window shall be located below @var{window}. The
The scenario sketched above is the standard way to obtain the desired
configuration. In Emacs 23 it was also the only way to do that since
-Emacs 23 did't allow splitting internal windows.
+Emacs 23 didn't allow splitting internal windows.
With Emacs 24 you can also proceed as follows: Split an initial window
@code{W6} by evaluating @code{(split-window W6 -3)} to produce the
@end deffn
The following function returns a copy of the list of windows in the
-cyclic odering.
+cyclic ordering.
@defun window-list-1 &optional window &optional minibuf &optional all_frames
This function returns a list of live windows. The optional arguments
The optional argument @var{window} specifies the first window to list
and defaults to the selected window. If @var{window} is not on the list
of windows returned, some other window will be listed first but no error
-is signalled.
+is signaled.
@end defun
The functions described below use @code{window-list-1} for generating a
returns @code{nil}. The argument @var{window} has to denote a live
window and defaults to the selected one. The argument
@var{buffer-or-name} must specify a buffer or the name of an existing
-buffer. An error is signalled when @var{window} is @dfn{strongly}
+buffer. An error is signaled when @var{window} is @dfn{strongly}
dedicated to its buffer (@pxref{Dedicated Windows}) and does not already
display @var{buffer-or-name}.
(@pxref{Dedicated Windows}) and is not the only window on its frame,
that window is deleted. If that window is the only window on its frame
and there are other frames on the frame's terminal, that frame is dealt
-with by the function spcecified by @code{frame-auto-hide-function}
+with by the function specified by @code{frame-auto-hide-function}
(@pxref{Quitting Windows}). Otherwise, the buffer provided by the
function @code{switch-to-prev-buffer} (@pxref{Window History}) is
displayed in the window instead.
displayed at a specified vertical position within the window. It does
not ``move point'' with respect to the text.
-If @var{count} is a nonnegative number, that puts the line containing
+If @var{count} is a non-negative number, that puts the line containing
point @var{count} lines down from the top of the window. If
@var{count} is a negative number, then it counts upward from the
bottom of the window, so that @minus{}1 stands for the last usable
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