window).
@end defun
+@anchor{Window Group}Sometimes several windows collectively and
+cooperatively display a buffer, for example, under the management of
+Follow Mode (@pxref{Follow Mode,,, emacs}), where the windows together
+display a bigger portion of the buffer than one window could alone.
+It is often useful to consider such a @dfn{window group} as a single
+entity. Several functions such as @code{window-group-start}
+(@pxref{Window Start and End}) allow you to do this by supplying, as
+an argument, one of the windows as a stand in for the whole group.
+
+@defun selected-window-group
+@vindex selected-window-group-function
+When the selected window is a member of a group of windows, this
+function returns a list of the windows in the group, ordered such that
+the first window in the list is displaying the earliest part of the
+buffer, and so on. Otherwise the function returns a list containing
+just the selected window.
+
+The selected window is considered part of a group when the buffer
+local variable @code{selected-window-group-function} is set to a
+function. In this case, @code{selected-window-group} calls it with no
+arguments and returns its result (which should be the list of windows
+in the group).
+@end defun
+
@node Windows and Frames
@section Windows and Frames
children.
@end defun
-@cindex window pixel height
-@cindex pixel height of a window
-@cindex total pixel height of a window
+@cindex window pixel width
+@cindex pixel width of a window
+@cindex total pixel width of a window
@defun window-pixel-width &optional Lisp_Object &optional window
This function returns the width of window @var{window} in pixels.
@cindex window body height
@cindex body height of a window
-@cindex window body width
The @dfn{body height} of a window is the height of its text area, which
does not include a mode or header line, a horizontal scroll bar, or a
bottom divider.
exceed its total height as returned by @code{window-total-height}.
@end defun
+@cindex window body width
@cindex body width of a window
-@cindex body size of a window
-@cindex window body size
The @dfn{body width} of a window is the width of its text area, which
does not include the scroll bar, fringes, margins or a right divider.
exceed its total width as returned by @code{window-total-width}.
@end defun
+@cindex window body size
+@cindex body size of a window
@defun window-body-size &optional window horizontal pixelwise
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
argument @var{pixelwise} is passed to the function called.
@end defun
- For compatibility with previous versions of Emacs,
+For compatibility with previous versions of Emacs,
@code{window-height} is an alias for @code{window-total-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.
(@pxref{Scroll Bars}), and display margins (@pxref{Display Margins}) are
described in the corresponding sections.
+If your Lisp program needs to make layout decisions, you will find the
+following function useful:
+
+@defun window-max-chars-per-line &optional window face
+This function returns the number of characters displayed in the
+specified @var{face} in the specified @var{window} (which must be a
+live window). If @var{face} was remapped (@pxref{Face Remapping}),
+the information is returned for the remapped face. If omitted or
+@code{nil}, @var{face} defaults to the default face, and @var{window}
+defaults to the selected window. Unlike @code{window-body-width},
+this function accounts for the actual size of the @var{face}'s font,
+instead of working in units of frame's canonical character width. It
+also accounts for space used by the continuation glyph, if
+@var{window} lacks one or both of its fringes.
+@end defun
+
@cindex fixed-size window
@vindex window-min-height
@vindex window-min-width
@code{window-min-height} and @code{window-min-width}, which specify the
smallest allowable window height and width. They also obey the variable
@code{window-size-fixed}, with which a window can be @dfn{fixed} in
-size:
+size (@pxref{Preserving Window Sizes}).
@defopt window-min-height
This option specifies the minimum total height, in lines, of any window.
position to change in response until after the next redisplay.
@end defun
+@defun window-group-start &optional window
+@vindex window-group-start-function
+This function is like @code{window-start}, except that when
+@var{window} is a part of a group of windows (@pxref{Window Group}),
+@code{window-group-start} returns the start position of the entire
+group. This condition holds when the buffer local variable
+@code{window-group-start-function} is set to a function. In this
+case, @code{window-group-start} calls the function with the single
+argument @var{window}, then returns its result.
+@end defun
+
@cindex window end position
@defun window-end &optional window update
This function returns the position where display of its buffer ends in
text will end if scrolling is not required.
@end defun
+@vindex window-group-end-function
+@defun window-group-end window update
+This function is like @code{window-end}, except that when @var{window}
+is a part of a group of windows (@pxref{Window Group}),
+@code{window-group-end} returns the end position of the entire group.
+This condition holds when the buffer local variable
+@code{window-group-end-function} is set to a function. In this case,
+@code{window-group-end} calls the function with the two arguments
+@var{window} and @var{update}, then returns its result. The argument
+@var{update} has the same meaning as in @code{window-end}.
+@end defun
+
@defun set-window-start window position &optional noforce
This function sets the display-start position of @var{window} to
@var{position} in @var{window}'s buffer. It returns @var{position}.
position that works well with point, and thus @var{position} is not used.
@end defun
+@vindex set-window-group-start-function
+@defun set-window-group-start window position &optional noforce
+This function is like @code{set-window-start}, except that when
+@var{window} is a part of a group of windows (@pxref{Window Group}),
+@code{set-window-group-start} sets the start position of the entire
+group. This condition holds when the buffer local variable
+@code{set-window-group-start-function} is set to a function. In this
+case, @code{set-window-group-start} calls the function with the three
+arguments @var{window}, @var{position}, and @var{noforce}, then
+returns its result. The arguments @var{position} and @var{noforce} in
+this function have the same meaning as in @code{set-window-start}.
+@end defun
+
@defun pos-visible-in-window-p &optional position window partially
This function returns non-@code{nil} if @var{position} is within the
range of text currently visible on the screen in @var{window}. It
@end example
@end defun
+@vindex pos-visible-in-window-group-p-function
+@defun pos-visible-in-window-group-p &optional position window partially
+This function is like @code{pos-visible-in-window-p}, except that when
+@var{window} is a part of a group of windows (@pxref{Window Group}),
+@code{pos-visible-in-window-group-p} tests the visibility of @var{pos}
+in the entire group, not just in the single @var{window}. This
+condition holds when the buffer local variable
+@code{pos-visible-in-window-group-p-function} is set to a function.
+In this case @code{pos-visible-in-window-group-p} calls the function
+with the three arguments @var{position}, @var{window}, and
+@var{partially}, then returns its result. The arguments
+@var{position} and @var{partially} have the same meaning as in
+@code{pos-visible-in-window-p}.
+@end defun
+
@defun window-line-height &optional line window
This function returns the height of text line @var{line} in
@var{window}. If @var{line} is one of @code{header-line} or
a more convenient way to achieve this.
@end deffn
+@vindex recenter-group-function
+@defun recenter-group &optional count
+This function is like @code{recenter}, except that when the selected
+window is part of a group of windows (@pxref{Window Group}),
+@code{recenter-group} scrolls the entire group. This condition holds
+when the buffer local variable @code{recenter-group-function} is set
+to a function. In this case, @code{recenter-group} calls the function
+with the argument @var{count}, then returns its result. The argument
+@var{count} has the same meaning as in @code{recenter}, but with
+respect to the entire window group.
+@end defun
+
@defopt recenter-redisplay
If this variable is non-@code{nil}, calling @code{recenter} with a
@code{nil} argument redraws the frame. The default value is
@group
(let ((edges (window-absolute-body-pixel-edges))
(position (pos-visible-in-window-p nil nil t)))
- (x-set-mouse-absolute-pixel-position
+ (set-mouse-absolute-pixel-position
(+ (nth 0 edges) (nth 0 position))
(+ (nth 1 edges) (nth 1 position))))
@end group
@end defvar
@defvar window-size-change-functions
-This variable holds a list of functions to be called if the size of any
-window changes for any reason. The functions are called just once per
-redisplay, and just once for each frame on which size changes have
-occurred.
+This variable holds a list of functions to be called if the size of
+any window changes for any reason. The functions are called at the
+beginning of a redisplay cycle, and just once for each frame on which
+size changes have occurred.
Each function receives the frame as its sole argument. There is no
direct way to find out which windows on that frame have changed size, or