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A frame is a rectangle on the screen that contains one or more Emacs windows. A frame initially contains a single main window (plus perhaps a minibuffer window) which you can subdivide vertically or horizontally into smaller windows.
When Emacs runs on a text-only terminal, it has just one frame, a terminal frame. There is no way to create another terminal frame after startup. If Emacs has an X display, it does not make a terminal frame; instead, it initially creates a single X window frame. You can create more; see section Creating Frames.
Function: framep object
This predicate returns
t if object is a frame, and
See section Emacs Display, for related information.
To create a new frame, call the function
Function: make-frame alist
This function creates a new frame, if the display mechanism permits creation of frames. (An X server does; an ordinary terminal does not.)
The argument is an alist specifying frame parameters. Any parameters
not mentioned in alist default according to the value of the
default-frame-alist; parameters not specified there
either default from the standard X defaults file and X resources.
The set of possible parameters depends in principle on what kind of window system Emacs uses to display its the frames. See section X Window Frame Parameters, for documentation of individual parameters you can specify when creating an X window frame.
An alist specifying default values of frame parameters. Each element has the form:
(parameter . value)
If you use options that specify window appearance when you invoke Emacs,
they take effect by adding elements to
A frame has many parameters that control how it displays.
These functions let you read and change the parameter values of a frame.
Function: frame-parameters frame
frame-parameters returns an alist of all the
parameters of frame.
Function: modify-frame-parameters frame alist
This function alters the parameters of frame frame based on the
elements of alist. Each element of alist has the form
(parm . value), where parm is a symbol naming a
parameter. If you don't mention a parameter in alist, its value
You can specify the parameters for the initial startup frame
initial-frame-alist in your `.emacs' file.
This variable's value is an alist of parameter values to when creating the initial X window frame.
If these parameters specify a separate minibuffer-only frame, and you have not created one, Emacs creates one for you.
This variable's value is an alist of parameter values to when creating an initial minibuffer-only frame--if such a frame is needed, according to the parameters for the main initial frame.
Just what parameters a frame has depends on what display mechanism it uses. Here is a table of the parameters of an X window frame:
onlymeans this frame is just a minibuffer, a minibuffer window (in some other frame) means the new frame uses that minibuffer.
nilmeans yes). (Horizontal scroll bars are not currently implemented.)
nilspecifies a bitmap icon,
nila text icon.
box. The value
barspecifies a vertical bar between characters as the cursor. The value
boxspecifies an ordinary black box overlaying the character after point; that is the default.
nil, this frame's window is never split automatically.
tfor visible, and
iconfor iconified. See section Visibility of Frames.
You can read or change the size and position of a frame using the
width. When you create a frame, you must specify either both
size parameters or neither. Likewise, you must specify either both
position parameters or neither. Whatever geometry parameters 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:
Function: set-frame-position frame left top
This function sets the position of the top left corner of frame---to left and top. These arguments are measured in pixels, counting from the top left corner of the screen.
Function: frame-height &optional frame
Function: frame-width &optional frame
These functions return the height and width of frame, measured in characters. If you don't supply frame, they use the selected frame.
Function: frame-pixel-height &optional frame
Function: frame-pixel-width &optional frame
These functions return the height and width of frame, measured in pixels. If you don't supply frame, they use the selected frame.
Function: frame-char-height &optional frame
Function: frame-char-width &optional frame
These functions return the height and width, respectively, of a character in frame, measured in pixels. The values depend on the choice of font. If you don't supply frame, these functions use the selected frame.
Function: set-frame-size frame cols rows
This function sets the size of frame, measured in characters; cols and rows specify the new width and height.
To set the size with values measured in pixels, use
modify-frame-parameters to set the
parameters. See section X Window Frame Parameters.
The old-fashioned functions
set-screen-width, which were used to specify the height and width
of the screen in Emacs versions that did not support multiple frames,
are still usable. They apply to the selected frame. See section Screen Size.
Function: x-parse-geometry geom
x-parse-geometry converts a standard X windows
geometry string to an alist which you can use as part of the argument to
The alist describes which parameters were specified in geom, and
gives the values specified for them. Each element looks like
(parameter . value). The possible parameter
(x-geometry "35x70+0-0") => ((width . 35) (height . 70) (left . 0) (top . -1))
Frames remain potentially visible until you explicitly 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. There is no way to cancel the deletion of a frame aside from restoring a saved frame configuration (see section Frame Configurations); this is similar to the way windows behave.
Command: delete-frame &optional frame
This function deletes the frame frame. By default, frame is the selected frame.
Function: frame-live-p frame
frame-live-p returns non-
nil if the frame
frame has not been deleted.
frame-list returns a list of all the frames that
have not been deleted. It is analogous to
buffers. The list that you get is newly created, so modifying the list
doesn't have any effect on the internals of Emacs.
This function returns a list of just the currently visible frames.
Function: next-frame &optional frame minibuf
next-frame lets you cycle conveniently through all
the frames from an arbitrary starting point. It returns the "next"
frame after frame in the cycle. If frame is omitted or
nil, it defaults to the selected frame.
The second argument, minibuf, says which frames to consider:
Function: previous-frame &optional frame minibuf
next-frame, but cycles through all frames in the opposite
All the non-minibuffer windows in a frame are arranged in a tree of
subdivisions; the root of this tree is available via the function
frame-root-window. Each window is part of one and
only one frame; you can get the frame with
Function: frame-root-window frame
This returns the root window of frame frame.
Function: window-frame window
This function returns the frame that window is on.
At any time, exactly one window on any frame is 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
Function: frame-selected-window frame
This function returns the window on frame which is selected within frame.
Conversely, selecting a window for Emacs with
makes that window selected within its frame. See section Selecting Windows.
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
minibuffer-window (see section Minibuffer Miscellany).
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 frame on which to find the
minibuffer to use. If you don't, then the minibuffer is found in the
frame which is the value of the variable
default-minibuffer-frame. Its value should be a frame which does
have a minibuffer.
At any time, one frame in Emacs is the selected frame. The selected window always resides on the selected frame.
This function returns the selected frame.
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 shift the focus to various X windows, overriding the normal behavior of the server.
Lisp programs can switch frames "temporarily" by calling
select-frame. This does not override the window
manager; rather, it escapes from the window manager's control until
that control is somehow reasserted.
Function: select-frame frame
This function selects frame frame, temporarily disregarding the X Windows focus. The selection of frame lasts until the next time the user does something to select a different frame, or until the next time this function is called.
Emacs 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
focus event. The command loop handles a focus event by calling
internal-select-frame. See section Focus Events.
Function: internal-select-frame frame
This function selects frame frame, assuming that the X server focus already points to frame.
Focus events normally do their job by invoking this command. Don't call it for any other reason.
A frame may be visible, invisible, or 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 in the screen, not even as an icon.
Command: make-frame-visible &optional frame
This function makes frame frame visible. If you omit frame, it makes the selected frame visible.
Command: make-frame-invisible &optional frame
This function makes frame frame invisible. If you omit frame, it makes the selected frame invisible.
Command: iconify-frame &optional frame
This function iconifies frame frame. If you omit frame, it iconifies the selected frame.
Function: frame-visible-p frame
This returns the visibility status of frame frame. The value is
t if frame is visible,
nil if it is invisible, and
icon if it is iconified.
The visibility status of a frame is also available as a frame parameter. You can read or change it as such. See section X Window Frame Parameters.
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.
A window's place in this ordering is not fixed; in fact, users tend to change the order frequently. Raising a window means moving it "up", to the top of the stack. 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 Emacs's X windows with these functions:
Function: raise-frame frame
This function raises frame frame.
Function: lower-frame frame
This function lowers frame frame.
You can also specify auto-raise (raising automatically when a frame is selected) or auto-lower (lowering automatically when it is deselected) for any frame using frame parameters. See section X Window Frame Parameters.
This function returns a frame configuration list which describes the current arrangement of frames, all their properties, and the window configuration of each one.
Function: set-frame-configuration configuration
This function restores the state of frames described in configuration.
Sometimes it is useful to track the mouse, which means, to display something to indicate where the mouse is and move the indicator as the mouse moves. For efficient mouse tracking, you need a way to wait until the mouse actually moves.
The convenient way to track the mouse is to ask for events to represent mouse motion. Then you can wait for motion by waiting for an event. In addition, you can easily handle any other sorts of events that may occur. That is useful, because normally you don't want to track the mouse forever--only until some other event, such as the release of a button.
Special Form: track-mouse body...
Execute body, meanwhile generating input events for mouse motion.
The code in body can read these events with
read-key-sequence. See section Motion Events, for the format of mouse
The value of
track-mouse is that of the last form in body.
The usual purpose of tracking mouse motion is to indicate on the screen the consequences of pushing or releasing a button at the current position.
The new functions
give access to the current position of the mouse.
This function returns a description of the position of the mouse. The
value looks like
(frame x . y), where x
and y are integers giving the position in pixels relative to the
top left corner of the inside of frame.
Function: set-mouse-position frame x y
Thus function warps the mouse to position x, y in frame frame. The arguments x and y are integers, giving the position in pixels relative to the top left corner of the inside of frame.
Warping the mouse means changing the screen position of the mouse as if the user had moved the physical mouse--thus simulating the effect of actual mouse motion.
Function: x-popup-menu position menu
This function displays a pop-up menu and returns an indication of what selection the user makes.
The argument position specifies where on the screen to put the menu. It can be either a mouse button event (which says to put the menu where the user actuated the button) or a list of this form:
((xoffset yoffset) window)
where xoffset and yoffset are positions measured in characters, counting from the top left corner of window's frame.
The argument menu says what to display in the menu. It can be a keymap or a list of keymaps (see section Menu Keymaps). Alternatively, it can have the following form:
(title pane1 pane2...)
where each pane is a list of form
(title (line item)...)
Each line should be a string, and each item should be the value to return if that line is chosen.
The X server records a set of selections which permit transfer of data between application programs. The various selections are distinguished by selection types, represented in Emacs by symbols. X clients including Emacs can read or set the selection for any given type.
Function: x-set-selection type data
This function sets a "selection" in the X server.
It takes two arguments: a selection type type, and the value to
assign to it, data. If data is
nil, it means to
clear out the selection. Otherwise, data may be a string, a
symbol, an integer (or a cons of two integers or list of two integers),
or a cons of two markers pointing to the same buffer. In the last case,
the selection is considered to be the text between the markers. The
data may also be a vector of valid non-vector selection values.
Each possible type has its own selection value, which changes
independently. The usual values of type are
SECONDARY; these are symbols with upper-case names, in accord
with X Windows conventions. The default is
Function: x-get-selection type data-type
This function accesses selections set up by Emacs or by other X
clients. It takes two optional arguments, type and
data-type. The default for type, the selection type, is
The data-type argument specifies the form of data conversion to
use, to convert the raw data obtained from another X client into Lisp
data. Meaningful values include
INTEGER. (These are symbols with
upper-case names in accord with X conventions.) The default for
The X server also has a set of numbered cut buffers which can store text or other data being moved between applications. Cut buffers are considered obsolete, but Emacs supports them for the sake of X clients that still use them.
Function: x-get-cut-buffer n
This function returns the contents of cut buffer number n.
Function: x-set-cut-buffer string
This function stores string into the first cut buffer (cut buffer 0), moving the other values down through the series of cut buffers, kill-ring-style.
This section describes how to access and change the overall status of the X server Emacs is using.
You can close the connection with the X server with the function
x-close-current-connection, and open a new one with
x-open-connection (perhaps with a different server and display).
This function closes the connection to the X server. It deletes all frames, making Emacs effectively inaccessible to the user; therefore, a Lisp program that closes the connection should open another one.
Function: x-open-connection display &optional resource-string
This function opens a connection to an X server, for use of display display.
The optional argument resource-string is a string of resource names and values, in the same format used in the `.Xresources' file. The values you specify override the resource values recorded in the X server itself. Here's an example of what this string might look like:
"*BorderWidth: 3\n*InternalBorder: 2\n"
t if the connected X display has color, and
Function: x-color-defined-p color
This function reports whether a color name is meaningful and supported
on the X display Emacs is using. It returns
t if the display
supports that color; otherwise,
Black-and-white displays support just two colors,
"white". Color displays support many other colors.
Function: x-synchronize flag
x-synchronize enables or disables synchronous
communication with the X server. It enables synchronous communication
if flag is non-
nil, and disables it if flag is
In synchronous mode, Emacs waits for a response to each X protocol command before doing anything else. This is useful for debugging Emacs, because protocol errors are reported right away, which helps you find the erroneous command. Synchronous mode is not the default because it is much slower.
Function: x-get-resource attribute &optional name class
x-get-resource retrieves a resource value from the X
Windows defaults database.
Resources are indexed by a combination of a key and a class. This function searches using a key of the form `instance.attribute', where instance is the name under which Emacs was invoked, and uses `Emacs' as the class.
The optional arguments component and subclass add to the key and the class, respectively. You must specify both of them or neither. If you specify them, the key is `instance.component.attribute', and the class is `Emacs.subclass'.
This section describes functions and a variable that you can use to get information about the capabilities and origin of the X server that Emacs is displaying its frames on.
This function returns the number of screens associated with the current display.
This function returns the list of version numbers of the X server in use.
This function returns the vendor supporting the X server in use.
This function returns the height of this X screen in pixels.
This function returns the height of this X screen in millimeters.
This function returns the width of this X screen in pixels.
This function returns the width of this X screen in millimeters.
This function returns the backing store capability of this screen.
Values can be the symbols
This function returns non-
nil if this X screen supports the
This function returns the number of planes this display supports.
This function returns the visual class for this X screen. The value is
one of the symbols
This function returns
t if the X screen in use is a color
This function returns the number of color cells this X screen supports.
This variable's value is is
t if no X window manager is in use.
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