21.4 The Window Object

Windows have the following accessible fields:

frame

The frame that this window is on.

mini_p

Non-nil if this window is a minibuffer window.

buffer

The buffer that the window is displaying. This may change often during the life of the window.

dedicated

Non-nil if this window is dedicated to its buffer.

pointm

This is the value of point in the current buffer when this window is selected; when it is not selected, it retains its previous value.

start

The position in the buffer that is the first character to be displayed in the window.

force_start

If this flag is non-nil, it says that the window has been scrolled explicitly by the Lisp program. This affects what the next redisplay does if point is off the screen: instead of scrolling the window to show the text around point, it moves point to a location that is on the screen.

last_modified

The modified field of the window’s buffer, as of the last time a redisplay completed in this window.

last_point

The buffer’s value of point, as of the last time a redisplay completed in this window.

left

This is the left-hand edge of the window, measured in columns. (The leftmost column on the screen is column 0.)

top

This is the top edge of the window, measured in lines. (The top line on the screen is line 0.)

height

The height of the window, measured in lines.

width

The width of the window, measured in columns.

next

This is the window that is the next in the chain of siblings. It is nil in a window that is the rightmost or bottommost of a group of siblings.

prev

This is the window that is the previous in the chain of siblings. It is nil in a window that is the leftmost or topmost of a group of siblings.

parent

Internally, SXEmacs arranges windows in a tree; each group of siblings has a parent window whose area includes all the siblings. This field points to a window’s parent.

Parent windows do not display buffers, and play little role in display except to shape their child windows. Emacs Lisp programs usually have no access to the parent windows; they operate on the windows at the leaves of the tree, which actually display buffers.

hscroll

This is the number of columns that the display in the window is scrolled horizontally to the left. Normally, this is 0.

use_time

This is the last time that the window was selected. The function get-lru-window uses this field.

display_table

The window’s display table, or nil if none is specified for it.

update_mode_line

Non-nil means this window’s mode line needs to be updated.

base_line_number

The line number of a certain position in the buffer, or nil. This is used for displaying the line number of point in the mode line.

base_line_pos

The position in the buffer for which the line number is known, or nil meaning none is known.

region_showing

If the region (or part of it) is highlighted in this window, this field holds the mark position that made one end of that region. Otherwise, this field is nil.