2 @c This is part of the GNU Emacs Lisp Reference Manual.
3 @c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1998, 1999, 2001,
4 @c 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
5 @c Free Software Foundation, Inc.
6 @c See the file elisp.texi for copying conditions.
7 @setfilename ../../info/frames
8 @node Frames, Positions, Windows, Top
12 A @dfn{frame} is a screen object that contains one or more Emacs
13 windows (@pxref{Windows}). It is the kind of object called a
14 ``window'' in the terminology of graphical environments; but we can't
15 call it a ``window'' here, because Emacs uses that word in a different
16 way. In Emacs Lisp, a @dfn{frame object} is a Lisp object that
17 represents a frame on the screen. @xref{Frame Type}.
19 A frame initially contains a single main window and/or a minibuffer
20 window; you can subdivide the main window vertically or horizontally
21 into smaller windows. @xref{Splitting Windows}.
24 A @dfn{terminal} is a display device capable of displaying one or
25 more Emacs frames. In Emacs Lisp, a @dfn{terminal object} is a Lisp
26 object that represents a terminal. @xref{Terminal Type}.
28 @cindex terminal frame
30 There are two classes of terminals: text-only terminals and
31 graphical terminals. Text-only terminals are non-graphics-capable
32 display devices, including ``terminal emulators'' such as xterm. On
33 text-only terminals, each frame occupies the entire terminal screen;
34 although you can create additional frames and switch between them,
35 only one frame can be shown at any given time. We refer to frames on
36 text-only terminals as @dfn{terminal frames}. Graphical terminals, on
37 the other hand, are graphics-capable windowing systems, such as the X
38 Window System. On a graphical terminal, Emacs can display multiple
39 frames simultaneously. We refer to such frames as @dfn{window
42 On GNU and Unix systems, you can create additional frames on any
43 available terminal, within a single Emacs session, regardless of
44 whether Emacs was started on a text-only or graphical terminal. Emacs
45 can display on both graphical and text-only terminals simultaneously.
46 This comes in handy, for instance, when you connect to the same
47 session from several remote locations. @xref{Multiple Terminals}.
50 This predicate returns a non-@code{nil} value if @var{object} is a
51 frame, and @code{nil} otherwise. For a frame, the value indicates which
52 kind of display the frame uses:
56 The frame is displayed in an X window.
58 A terminal frame on a character display.
60 The frame is displayed on MS-Windows 9X/NT.
62 The frame is displayed on a GNUstep or Macintosh Cocoa display.
64 The frame is displayed on an MS-DOS terminal.
68 @defun frame-terminal &optional frame
69 This function returns the terminal object that displays @var{frame}.
70 If @var{frame} is @code{nil} or unspecified, it defaults to the
74 @defun terminal-live-p object
75 This predicate returns a non-@code{nil} value if @var{object} is a
76 terminal that is alive (i.e.@: was not deleted), and @code{nil}
77 otherwise. For live terminals, the return value indicates what kind
78 of frames are displayed on that terminal; the list of possible values
79 is the same as for @code{framep} above.
83 * Creating Frames:: Creating additional frames.
84 * Multiple Terminals:: Displaying on several different devices.
85 * Frame Parameters:: Controlling frame size, position, font, etc.
86 * Terminal Parameters:: Parameters common for all frames on terminal.
87 * Frame Titles:: Automatic updating of frame titles.
88 * Deleting Frames:: Frames last until explicitly deleted.
89 * Finding All Frames:: How to examine all existing frames.
90 * Frames and Windows:: A frame contains windows;
91 display of text always works through windows.
92 * Minibuffers and Frames:: How a frame finds the minibuffer to use.
93 * Input Focus:: Specifying the selected frame.
94 * Visibility of Frames:: Frames may be visible or invisible, or icons.
95 * Raising and Lowering:: Raising a frame makes it hide other windows;
96 lowering it makes the others hide it.
97 * Frame Configurations:: Saving the state of all frames.
98 * Mouse Tracking:: Getting events that say when the mouse moves.
99 * Mouse Position:: Asking where the mouse is, or moving it.
100 * Pop-Up Menus:: Displaying a menu for the user to select from.
101 * Dialog Boxes:: Displaying a box to ask yes or no.
102 * Pointer Shape:: Specifying the shape of the mouse pointer.
103 * Window System Selections:: Transferring text to and from other X clients.
104 * Drag and Drop:: Internals of Drag-and-Drop implementation.
105 * Color Names:: Getting the definitions of color names.
106 * Text Terminal Colors:: Defining colors for text-only terminals.
107 * Resources:: Getting resource values from the server.
108 * Display Feature Testing:: Determining the features of a terminal.
111 @node Creating Frames
112 @section Creating Frames
114 To create a new frame, call the function @code{make-frame}.
116 @defun make-frame &optional alist
117 This function creates and returns a new frame, displaying the current
120 The @var{alist} argument is an alist that specifies frame parameters
121 for the new frame. @xref{Frame Parameters}. If you specify the
122 @code{terminal} parameter in @var{alist}, the new frame is created on
123 that terminal. Otherwise, if you specify the @code{window-system}
124 frame parameter in @var{alist}, that determines whether the frame
125 should be displayed on a text-only or graphical terminal.
126 @xref{Window Systems}. If neither is specified, the new frame is
127 created in the same terminal as the selected frame.
129 Any parameters not mentioned in @var{alist} default to the values in
130 the alist @code{default-frame-alist} (@pxref{Initial Parameters});
131 parameters not specified there default from the X resources or its
132 equivalent on your operating system (@pxref{X Resources,, X Resources,
133 emacs, The GNU Emacs Manual}). After the frame is created, Emacs
134 applies any parameters listed in @code{frame-inherited-parameters}
135 (see below) and not present in the argument, taking the values from
136 the frame that was selected when @code{make-frame} was called.
138 This function itself does not make the new frame the selected frame.
139 @xref{Input Focus}. The previously selected frame remains selected.
140 On graphical terminals, however, the windowing system may select the
141 new frame for its own reasons.
144 @defvar before-make-frame-hook
145 A normal hook run by @code{make-frame} before it creates the frame.
148 @defvar after-make-frame-functions
149 An abnormal hook run by @code{make-frame} after it creates the frame.
150 Each function in @code{after-make-frame-functions} receives one argument, the
154 @defvar frame-inherited-parameters
155 This variable specifies the list of frame parameters that a newly
156 created frame inherits from the currently selected frame. For each
157 parameter (a symbol) that is an element in the list and is not present
158 in the argument to @code{make-frame}, the function sets the value of
159 that parameter in the created frame to its value in the selected
163 @node Multiple Terminals
164 @section Multiple Terminals
165 @cindex multiple terminals
167 @cindex multiple X displays
168 @cindex displays, multiple
170 Emacs represents each terminal, whether graphical or text-only, as a
171 @dfn{terminal object} data type (@pxref{Terminal Type}). On GNU and
172 Unix systems, Emacs can use multiple terminals simultaneously in each
173 session. On other systems, it can only use a single terminal. Each
174 terminal object has the following attributes:
178 The name of the device used by the terminal (e.g., @samp{:0.0} or
182 The terminal and keyboard coding systems used on the terminal.
183 @xref{Terminal I/O Encoding}.
186 The kind of display associated with the terminal. This is the symbol
187 returned by the function @code{terminal-live-p} (i.e., @code{x},
188 @code{t}, @code{w32}, @code{ns}, or @code{pc}). @xref{Frames}.
191 A list of terminal parameters. @xref{Terminal Parameters}.
194 There is no primitive for creating terminal objects. Emacs creates
195 them as needed, such as when you call @code{make-frame-on-display}
196 (which is described below).
198 @defun terminal-name &optional terminal
199 This function returns the file name of the device used by
200 @var{terminal}. If @var{terminal} is omitted or @code{nil}, it
201 defaults to the selected frame's terminal. @var{terminal} can also be
202 a frame, meaning that frame's terminal.
206 This function returns a list of all terminal objects currently in use.
209 @defun get-device-terminal device
210 This function returns a terminal whose device name is given by
211 @var{device}. If @var{device} is a string, it can be either the file
212 name of a terminal device, or the name of an X display of the form
213 @samp{@var{host}:@var{server}.@var{screen}}. If @var{device} is a
214 frame, this function returns that frame's terminal; @code{nil} means
215 the selected frame. Finally, if @var{device} is a terminal object
216 that represents a live terminal, that terminal is returned. The
217 function signals an error if its argument is none of the above.
220 @defun delete-terminal &optional terminal force
221 This function deletes all frames on @var{terminal} and frees the
222 resources used by it. It runs the abnormal hook
223 @code{delete-terminal-functions}, passing @var{terminal} as the
224 argument to each function.
226 If @var{terminal} is omitted or @code{nil}, it defaults to the
227 selected frame's terminal. @var{terminal} can also be a frame,
228 meaning that frame's terminal.
230 Normally, this function signals an error if you attempt to delete the
231 sole active terminal, but if @var{force} is non-@code{nil}, you are
232 allowed to do so. Emacs automatically calls this function when the
233 last frame on a terminal is deleted (@pxref{Deleting Frames}).
236 @defvar delete-terminal-functions
237 An abnormal hook run by @code{delete-terminal}. Each function
238 receives one argument, the @var{terminal} argument passed to
239 @code{delete-terminal}. Due to technical details, the functions may
240 be called either just before the terminal is deleted, or just
244 @cindex terminal-local variables
245 A few Lisp variables are @dfn{terminal-local}; that is, they have a
246 separate binding for each terminal. The binding in effect at any time
247 is the one for the terminal that the currently selected frame belongs
248 to. These variables include @code{default-minibuffer-frame},
249 @code{defining-kbd-macro}, @code{last-kbd-macro}, and
250 @code{system-key-alist}. They are always terminal-local, and can
251 never be buffer-local (@pxref{Buffer-Local Variables}).
253 On GNU and Unix systems, each X display is a separate graphical
254 terminal. When Emacs is started from within the X window system, it
255 uses the X display chosen with the @code{DISPLAY} environment
256 variable, or with the @samp{--display} option. @xref{Initial
257 Options,,, emacs, The GNU Emacs Manual}. Emacs can connect to other X
258 displays via the command @code{make-frame-on-display}. Each X display
259 has its own selected frame and its own minibuffer windows; however,
260 only one of those frames is ``@emph{the} selected frame'' at any given
261 moment (@pxref{Input Focus}). Emacs can even connect to other
262 text-only terminals, by interacting with the @command{emacsclient}
263 program. @xref{Emacs Server,,, emacs, The GNU Emacs Manual}.
265 A single X server can handle more than one display. Each X display
266 has a three-part name, @samp{@var{host}:@var{server}.@var{screen}}.
267 The first two parts, @var{host} and @var{server}, identify the X
268 server; the third part, @var{screen}, identifies a screen number on
269 that X server. When you use two or more screens belonging to one
270 server, Emacs knows by the similarity in their names that they share a
273 On some ``multi-monitor'' setups, a single X display outputs to more
274 than one monitor. Currently, there is no way for Emacs to distinguish
275 between the different physical monitors.
277 @deffn Command make-frame-on-display display &optional parameters
278 This function creates and returns a new frame on @var{display}, taking
279 the other frame parameters from the alist @var{parameters}.
280 @var{display} should be the name of an X display (a string).
282 Before creating the frame, this function ensures that Emacs is ``set
283 up'' to display graphics. For instance, if Emacs has not processed X
284 resources (e.g., if it was started on a text-only terminal), it does
285 so at this time. In all other respects, this function behaves like
286 @code{make-frame} (@pxref{Creating Frames}).
289 @defun x-display-list
290 This function returns a list that indicates which X displays Emacs has
291 a connection to. The elements of the list are strings, and each one
295 @defun x-open-connection display &optional xrm-string must-succeed
296 This function opens a connection to the X display @var{display},
297 without creating a frame on that display. Normally, Emacs Lisp
298 programs need not call this function, as @code{make-frame-on-display}
299 calls it automatically. The only reason for calling it is to check
300 whether communication can be established with a given X display.
302 The optional argument @var{xrm-string}, if not @code{nil}, is a string
303 of resource names and values, in the same format used in the
304 @file{.Xresources} file. @xref{X Resources,, X Resources, emacs, The
305 GNU Emacs Manual}. These values apply to all Emacs frames created on
306 this display, overriding the resource values recorded in the X server.
307 Here's an example of what this string might look like:
310 "*BorderWidth: 3\n*InternalBorder: 2\n"
313 If @var{must-succeed} is non-@code{nil}, failure to open the connection
314 terminates Emacs. Otherwise, it is an ordinary Lisp error.
317 @defun x-close-connection display
318 This function closes the connection to display @var{display}. Before
319 you can do this, you must first delete all the frames that were open
320 on that display (@pxref{Deleting Frames}).
323 @node Frame Parameters
324 @section Frame Parameters
325 @cindex frame parameters
327 A frame has many parameters that control its appearance and behavior.
328 Just what parameters a frame has depends on what display mechanism it
331 Frame parameters exist mostly for the sake of window systems. A
332 terminal frame has a few parameters, mostly for compatibility's sake;
333 only the @code{height}, @code{width}, @code{name}, @code{title},
334 @code{menu-bar-lines}, @code{buffer-list} and @code{buffer-predicate}
335 parameters do something special. If the terminal supports colors, the
336 parameters @code{foreground-color}, @code{background-color},
337 @code{background-mode} and @code{display-type} are also meaningful.
338 If the terminal supports frame transparency, the parameter
339 @code{alpha} is also meaningful.
341 You can use frame parameters to define frame-local bindings for
342 variables. @xref{Frame-Local Variables}.
345 * Parameter Access:: How to change a frame's parameters.
346 * Initial Parameters:: Specifying frame parameters when you make a frame.
347 * Window Frame Parameters:: List of frame parameters for window systems.
348 * Size and Position:: Changing the size and position of a frame.
349 * Geometry:: Parsing geometry specifications.
352 @node Parameter Access
353 @subsection Access to Frame Parameters
355 These functions let you read and change the parameter values of a
358 @defun frame-parameter frame parameter
359 This function returns the value of the parameter @var{parameter} (a
360 symbol) of @var{frame}. If @var{frame} is @code{nil}, it returns the
361 selected frame's parameter. If @var{frame} has no setting for
362 @var{parameter}, this function returns @code{nil}.
365 @defun frame-parameters &optional frame
366 The function @code{frame-parameters} returns an alist listing all the
367 parameters of @var{frame} and their values. If @var{frame} is
368 @code{nil} or omitted, this returns the selected frame's parameters
371 @defun modify-frame-parameters frame alist
372 This function alters the parameters of frame @var{frame} based on the
373 elements of @var{alist}. Each element of @var{alist} has the form
374 @code{(@var{parm} . @var{value})}, where @var{parm} is a symbol naming a
375 parameter. If you don't mention a parameter in @var{alist}, its value
376 doesn't change. If @var{frame} is @code{nil}, it defaults to the selected
379 You can use this function to define frame-local bindings for
380 variables, see @ref{Frame-Local Variables}.
383 @defun set-frame-parameter frame parm value
384 This function sets the frame parameter @var{parm} to the specified
385 @var{value}. If @var{frame} is @code{nil}, it defaults to the
389 @defun modify-all-frames-parameters alist
390 This function alters the frame parameters of all existing frames
391 according to @var{alist}, then modifies @code{default-frame-alist}
392 (and, if necessary, @code{initial-frame-alist}) to apply the same
393 parameter values to frames that will be created henceforth.
396 @node Initial Parameters
397 @subsection Initial Frame Parameters
399 You can specify the parameters for the initial startup frame
400 by setting @code{initial-frame-alist} in your init file (@pxref{Init File}).
402 @defopt initial-frame-alist
403 This variable's value is an alist of parameter values used when creating
404 the initial window frame. You can set this variable to specify the
405 appearance of the initial frame without altering subsequent frames.
406 Each element has the form:
409 (@var{parameter} . @var{value})
412 Emacs creates the initial frame before it reads your init
413 file. After reading that file, Emacs checks @code{initial-frame-alist},
414 and applies the parameter settings in the altered value to the already
415 created initial frame.
417 If these settings affect the frame geometry and appearance, you'll see
418 the frame appear with the wrong ones and then change to the specified
419 ones. If that bothers you, you can specify the same geometry and
420 appearance with X resources; those do take effect before the frame is
421 created. @xref{X Resources,, X Resources, emacs, The GNU Emacs Manual}.
423 X resource settings typically apply to all frames. If you want to
424 specify some X resources solely for the sake of the initial frame, and
425 you don't want them to apply to subsequent frames, here's how to achieve
426 this. Specify parameters in @code{default-frame-alist} to override the
427 X resources for subsequent frames; then, to prevent these from affecting
428 the initial frame, specify the same parameters in
429 @code{initial-frame-alist} with values that match the X resources.
432 If these parameters specify a separate minibuffer-only frame with
433 @code{(minibuffer . nil)}, and you have not created one, Emacs creates
436 @defopt minibuffer-frame-alist
437 This variable's value is an alist of parameter values used when
438 creating an initial minibuffer-only frame. This is the
439 minibuffer-only frame that Emacs creates if @code{initial-frame-alist}
440 specifies a frame with no minibuffer.
443 @defopt default-frame-alist
444 This is an alist specifying default values of frame parameters for all
445 Emacs frames---the first frame, and subsequent frames. When using the X
446 Window System, you can get the same results by means of X resources
449 Setting this variable does not affect existing frames.
452 Functions that display a buffer in a separate frame can override the
453 default parameters by supplying their own parameters. @xref{Definition
454 of special-display-frame-alist}.
456 If you use options that specify window appearance when you invoke Emacs,
457 they take effect by adding elements to @code{default-frame-alist}. One
458 exception is @samp{-geometry}, which adds the specified position to
459 @code{initial-frame-alist} instead. @xref{Emacs Invocation,, Command
460 Line Arguments for Emacs Invocation, emacs, The GNU Emacs Manual}.
462 @node Window Frame Parameters
463 @subsection Window Frame Parameters
465 Just what parameters a frame has depends on what display mechanism
466 it uses. This section describes the parameters that have special
467 meanings on some or all kinds of terminals. Of these, @code{name},
468 @code{title}, @code{height}, @code{width}, @code{buffer-list} and
469 @code{buffer-predicate} provide meaningful information in terminal
470 frames, and @code{tty-color-mode} is meaningful @emph{only} in
474 * Basic Parameters:: Parameters that are fundamental.
475 * Position Parameters:: The position of the frame on the screen.
476 * Size Parameters:: Frame's size.
477 * Layout Parameters:: Size of parts of the frame, and
478 enabling or disabling some parts.
479 * Buffer Parameters:: Which buffers have been or should be shown.
480 * Management Parameters:: Communicating with the window manager.
481 * Cursor Parameters:: Controlling the cursor appearance.
482 * Font and Color Parameters:: Fonts and colors for the frame text.
485 @node Basic Parameters
486 @subsubsection Basic Parameters
488 These frame parameters give the most basic information about the
489 frame. @code{title} and @code{name} are meaningful on all terminals.
493 The display on which to open this frame. It should be a string of the
494 form @code{"@var{host}:@var{dpy}.@var{screen}"}, just like the
495 @code{DISPLAY} environment variable.
498 This parameter describes the range of possible colors that can be used
499 in this frame. Its value is @code{color}, @code{grayscale} or
503 If a frame has a non-@code{nil} title, it appears in the window
504 system's title bar at the top of the frame, and also in the mode line
505 of windows in that frame if @code{mode-line-frame-identification} uses
506 @samp{%F} (@pxref{%-Constructs}). This is normally the case when
507 Emacs is not using a window system, and can only display one frame at
508 a time. @xref{Frame Titles}.
511 The name of the frame. The frame name serves as a default for the frame
512 title, if the @code{title} parameter is unspecified or @code{nil}. If
513 you don't specify a name, Emacs sets the frame name automatically
514 (@pxref{Frame Titles}).
516 If you specify the frame name explicitly when you create the frame, the
517 name is also used (instead of the name of the Emacs executable) when
518 looking up X resources for the frame.
521 @node Position Parameters
522 @subsubsection Position Parameters
524 Position parameters' values are normally measured in pixels, but on
525 text-only terminals they count characters or lines instead.
529 The position, in pixels, of the left (or right) edge of the frame with
530 respect to the left (or right) edge of the screen. The value may be:
534 A positive integer relates the left edge of the frame to the left edge
535 of the screen. A negative integer relates the right frame edge to the
538 @item @code{(+ @var{pos})}
539 This specifies the position of the left frame edge relative to the left
540 screen edge. The integer @var{pos} may be positive or negative; a
541 negative value specifies a position outside the screen.
543 @item @code{(- @var{pos})}
544 This specifies the position of the right frame edge relative to the right
545 screen edge. The integer @var{pos} may be positive or negative; a
546 negative value specifies a position outside the screen.
549 Some window managers ignore program-specified positions. If you want to
550 be sure the position you specify is not ignored, specify a
551 non-@code{nil} value for the @code{user-position} parameter as well.
554 The screen position of the top (or bottom) edge, in pixels, with respect
555 to the top (or bottom) edge of the screen. It works just like
556 @code{left}, except vertically instead of horizontally.
559 The screen position of the left edge @emph{of the frame's icon}, in
560 pixels, counting from the left edge of the screen. This takes effect if
561 and when the frame is iconified.
563 If you specify a value for this parameter, then you must also specify
564 a value for @code{icon-top} and vice versa. The window manager may
565 ignore these two parameters.
568 The screen position of the top edge @emph{of the frame's icon}, in
569 pixels, counting from the top edge of the screen. This takes effect if
570 and when the frame is iconified.
573 When you create a frame and specify its screen position with the
574 @code{left} and @code{top} parameters, use this parameter to say whether
575 the specified position was user-specified (explicitly requested in some
576 way by a human user) or merely program-specified (chosen by a program).
577 A non-@code{nil} value says the position was user-specified.
579 Window managers generally heed user-specified positions, and some heed
580 program-specified positions too. But many ignore program-specified
581 positions, placing the window in a default fashion or letting the user
582 place it with the mouse. Some window managers, including @code{twm},
583 let the user specify whether to obey program-specified positions or
586 When you call @code{make-frame}, you should specify a non-@code{nil}
587 value for this parameter if the values of the @code{left} and @code{top}
588 parameters represent the user's stated preference; otherwise, use
592 @node Size Parameters
593 @subsubsection Size Parameters
595 Size parameters' values are normally measured in pixels, but on
596 text-only terminals they count characters or lines instead.
600 The height of the frame contents, in characters. (To get the height in
601 pixels, call @code{frame-pixel-height}; see @ref{Size and Position}.)
604 The width of the frame contents, in characters. (To get the width in
605 pixels, call @code{frame-pixel-width}; see @ref{Size and Position}.)
608 This does for the size parameters @code{height} and @code{width} what
609 the @code{user-position} parameter (see above) does for the position
610 parameters @code{top} and @code{left}.
613 Specify that width, height or both shall be maximized. The value
614 @code{fullwidth} specifies that width shall be as wide as possible.
615 The value @code{fullheight} specifies that height shall be as tall as
616 possible. The value @code{fullboth} specifies that both the width and
617 the height shall be set to the size of the screen. The value
618 @code{maximized} specifies that the frame shall be maximized. The
619 difference between @code{maximized} and @code{fullboth} is that the
620 former still has window manager decorations while the latter really
621 covers the whole screen.
624 @node Layout Parameters
625 @subsubsection Layout Parameters
627 These frame parameters enable or disable various parts of the
628 frame, or control their sizes.
632 The width in pixels of the frame's border.
634 @item internal-border-width
635 The distance in pixels between text (or fringe) and the frame's border.
637 @item vertical-scroll-bars
638 Whether the frame has scroll bars for vertical scrolling, and which side
639 of the frame they should be on. The possible values are @code{left},
640 @code{right}, and @code{nil} for no scroll bars.
643 @item horizontal-scroll-bars
644 Whether the frame has scroll bars for horizontal scrolling
645 (non-@code{nil} means yes). Horizontal scroll bars are not currently
649 @item scroll-bar-width
650 The width of vertical scroll bars, in pixels, or @code{nil} meaning to
651 use the default width.
655 The default width of the left and right fringes of windows in this
656 frame (@pxref{Fringes}). If either of these is zero, that effectively
657 removes the corresponding fringe. A value of @code{nil} stands for
658 the standard fringe width, which is the width needed to display the
661 The combined fringe widths must add up to an integral number of
662 columns, so the actual default fringe widths for the frame may be
663 larger than the specified values. The extra width needed to reach an
664 acceptable total is distributed evenly between the left and right
665 fringe. However, you can force one fringe or the other to a precise
666 width by specifying that width as a negative integer. If both widths are
667 negative, only the left fringe gets the specified width.
670 The number of lines to allocate at the top of the frame for a menu
671 bar. The default is 1. A value of @code{nil} means don't display a
672 menu bar. @xref{Menu Bar}. (The X toolkit and GTK allow at most one
673 menu bar line; they treat larger values as 1.)
676 The number of lines to use for the tool bar. A value of @code{nil}
677 means don't display a tool bar. (GTK and Nextstep allow at most one
678 tool bar line; they treat larger values as 1.)
680 @item tool-bar-position
681 The position of the tool bar. Currently only for the GTK tool bar.
682 Value can be one of @code{top}, @code{bottom} @code{left}, @code{right}.
683 The default is @code{top}.
686 Additional space to leave below each text line, in pixels (a positive
687 integer). @xref{Line Height}, for more information.
690 @node Buffer Parameters
691 @subsubsection Buffer Parameters
693 These frame parameters, meaningful on all kinds of terminals, deal
694 with which buffers have been, or should, be displayed in the frame.
698 Whether this frame has its own minibuffer. The value @code{t} means
699 yes, @code{nil} means no, @code{only} means this frame is just a
700 minibuffer. If the value is a minibuffer window (in some other
701 frame), the frame uses that minibuffer.
703 This frame parameter takes effect when the frame is created, and can
704 not be changed afterwards.
706 @item buffer-predicate
707 The buffer-predicate function for this frame. The function
708 @code{other-buffer} uses this predicate (from the selected frame) to
709 decide which buffers it should consider, if the predicate is not
710 @code{nil}. It calls the predicate with one argument, a buffer, once for
711 each buffer; if the predicate returns a non-@code{nil} value, it
712 considers that buffer.
715 A list of buffers that have been selected in this frame,
716 ordered most-recently-selected first.
719 If non-@code{nil}, this frame's window is never split automatically.
722 @node Management Parameters
723 @subsubsection Window Management Parameters
724 @cindex window manager, and frame parameters
726 These frame parameters, meaningful only on window system displays,
727 interact with the window manager.
731 The state of visibility of the frame. There are three possibilities:
732 @code{nil} for invisible, @code{t} for visible, and @code{icon} for
733 iconified. @xref{Visibility of Frames}.
736 Whether selecting the frame raises it (non-@code{nil} means yes).
739 Whether deselecting the frame lowers it (non-@code{nil} means yes).
742 The type of icon to use for this frame when it is iconified. If the
743 value is a string, that specifies a file containing a bitmap to use.
744 Any other non-@code{nil} value specifies the default bitmap icon (a
745 picture of a gnu); @code{nil} specifies a text icon.
748 The name to use in the icon for this frame, when and if the icon
749 appears. If this is @code{nil}, the frame's title is used.
752 The number of the window-system window used by the frame
753 to contain the actual Emacs windows.
755 @item outer-window-id
756 The number of the outermost window-system window used for the whole frame.
759 If non-@code{nil}, tell Xt to wait for the window manager to confirm
760 geometry changes. Some window managers, including versions of Fvwm2
761 and KDE, fail to confirm, so Xt hangs. Set this to @code{nil} to
762 prevent hanging with those window managers.
765 If non-@code{nil}, the frame is visible on all virtual desktops on systems
766 with virtual desktops.
770 @c ??? Not yet working.
771 The X window number of the window that should be the parent of this one.
772 Specifying this lets you create an Emacs window inside some other
773 application's window. (It is not certain this will be implemented; try
774 it and see if it works.)
778 @node Cursor Parameters
779 @subsubsection Cursor Parameters
781 This frame parameter controls the way the cursor looks.
785 How to display the cursor. Legitimate values are:
789 Display a filled box. (This is the default.)
791 Display a hollow box.
793 Don't display a cursor.
795 Display a vertical bar between characters.
796 @item (bar . @var{width})
797 Display a vertical bar @var{width} pixels wide between characters.
799 Display a horizontal bar.
800 @item (hbar . @var{height})
801 Display a horizontal bar @var{height} pixels high.
806 The buffer-local variable @code{cursor-type} overrides the value of
807 the @code{cursor-type} frame parameter, but if it is @code{t}, that
808 means to use the cursor specified for the frame.
810 @defopt blink-cursor-alist
811 This variable specifies how to blink the cursor. Each element has the
812 form @code{(@var{on-state} . @var{off-state})}. Whenever the cursor
813 type equals @var{on-state} (comparing using @code{equal}), the
814 corresponding @var{off-state} specifies what the cursor looks like
815 when it blinks ``off.'' Both @var{on-state} and @var{off-state}
816 should be suitable values for the @code{cursor-type} frame parameter.
818 There are various defaults for how to blink each type of cursor, if
819 the type is not mentioned as an @var{on-state} here. Changes in this
820 variable do not take effect immediately, only when you specify the
821 @code{cursor-type} frame parameter.
824 @defopt cursor-in-non-selected-windows
825 This variable controls how the cursor looks in a window that is not
826 selected. It supports the same values as the @code{cursor-type} frame
827 parameter; also, @code{nil} means don't display a cursor in
828 nonselected windows, and @code{t} (the default) means use a standard
829 modification of the usual cursor type (solid box becomes hollow box,
830 and bar becomes a narrower bar).
833 @node Font and Color Parameters
834 @subsubsection Font and Color Parameters
836 These frame parameters control the use of fonts and colors.
840 A list of symbols, specifying the @dfn{font backends} to use for
841 drawing fonts in the frame, in order of priority. On X, there are
842 currently two available font backends: @code{x} (the X core font
843 driver) and @code{xft} (the Xft font driver). On other systems, there
844 is only one available font backend, so it does not make sense to
845 modify this frame parameter.
847 @item background-mode
848 This parameter is either @code{dark} or @code{light}, according
849 to whether the background color is a light one or a dark one.
852 @cindex standard colors for character terminals
853 This parameter overrides the terminal's color support as given by the
854 system's terminal capabilities database in that this parameter's value
855 specifies the color mode to use in terminal frames. The value can be
856 either a symbol or a number. A number specifies the number of colors
857 to use (and, indirectly, what commands to issue to produce each
858 color). For example, @code{(tty-color-mode . 8)} specifies use of the
859 ANSI escape sequences for 8 standard text colors. A value of -1 turns
862 If the parameter's value is a symbol, it specifies a number through
863 the value of @code{tty-color-mode-alist}, and the associated number is
867 @cindex gamma correction
868 If this is a number, Emacs performs ``gamma correction'' which adjusts
869 the brightness of all colors. The value should be the screen gamma of
870 your display, a floating point number.
872 Usual PC monitors have a screen gamma of 2.2, so color values in
873 Emacs, and in X windows generally, are calibrated to display properly
874 on a monitor with that gamma value. If you specify 2.2 for
875 @code{screen-gamma}, that means no correction is needed. Other values
876 request correction, designed to make the corrected colors appear on
877 your screen the way they would have appeared without correction on an
878 ordinary monitor with a gamma value of 2.2.
880 If your monitor displays colors too light, you should specify a
881 @code{screen-gamma} value smaller than 2.2. This requests correction
882 that makes colors darker. A screen gamma value of 1.5 may give good
883 results for LCD color displays.
886 @cindex opacity, frame
887 @cindex transparency, frame
888 @vindex frame-alpha-lower-limit
889 This parameter specifies the opacity of the frame, on graphical
890 displays that support variable opacity. It should be an integer
891 between 0 and 100, where 0 means completely transparent and 100 means
892 completely opaque. It can also have a @code{nil} value, which tells
893 Emacs not to set the frame opacity (leaving it to the window manager).
895 To prevent the frame from disappearing completely from view, the
896 variable @code{frame-alpha-lower-limit} defines a lower opacity limit.
897 If the value of the frame parameter is less than the value of this
898 variable, Emacs uses the latter. By default,
899 @code{frame-alpha-lower-limit} is 20.
901 The @code{alpha} frame parameter can also be a cons cell
902 @code{(@samp{active} . @samp{inactive})}, where @samp{active} is the
903 opacity of the frame when it is selected, and @samp{inactive} is the
904 opactity when it is not selected.
907 The following frame parameters are semi-obsolete in that they are
908 automatically equivalent to particular face attributes of particular
909 faces (@pxref{Standard Faces,,, emacs, The Emacs Manual}):
913 The name of the font for displaying text in the frame. This is a
914 string, either a valid font name for your system or the name of an Emacs
915 fontset (@pxref{Fontsets}). It is equivalent to the @code{font}
916 attribute of the @code{default} face.
918 @item foreground-color
919 The color to use for the image of a character. It is equivalent to
920 the @code{:foreground} attribute of the @code{default} face.
922 @item background-color
923 The color to use for the background of characters. It is equivalent to
924 the @code{:background} attribute of the @code{default} face.
927 The color for the mouse pointer. It is equivalent to the @code{:background}
928 attribute of the @code{mouse} face.
931 The color for the cursor that shows point. It is equivalent to the
932 @code{:background} attribute of the @code{cursor} face.
935 The color for the border of the frame. It is equivalent to the
936 @code{:background} attribute of the @code{border} face.
938 @item scroll-bar-foreground
939 If non-@code{nil}, the color for the foreground of scroll bars. It is
940 equivalent to the @code{:foreground} attribute of the
941 @code{scroll-bar} face.
943 @item scroll-bar-background
944 If non-@code{nil}, the color for the background of scroll bars. It is
945 equivalent to the @code{:background} attribute of the
946 @code{scroll-bar} face.
949 @node Size and Position
950 @subsection Frame Size And Position
951 @cindex size of frame
956 You can read or change the size and position of a frame using the
957 frame parameters @code{left}, @code{top}, @code{height}, and
958 @code{width}. Whatever geometry parameters you don't specify are chosen
959 by the window manager in its usual fashion.
961 Here are some special features for working with sizes and positions.
962 (For the precise meaning of ``selected frame'' used by these functions,
963 see @ref{Input Focus}.)
965 @defun set-frame-position frame left top
966 This function sets the position of the top left corner of @var{frame} to
967 @var{left} and @var{top}. These arguments are measured in pixels, and
968 normally count from the top left corner of the screen.
970 Negative parameter values position the bottom edge of the window up from
971 the bottom edge of the screen, or the right window edge to the left of
972 the right edge of the screen. It would probably be better if the values
973 were always counted from the left and top, so that negative arguments
974 would position the frame partly off the top or left edge of the screen,
975 but it seems inadvisable to change that now.
978 @defun frame-height &optional frame
979 @defunx frame-width &optional frame
980 These functions return the height and width of @var{frame}, measured in
981 lines and columns. If you don't supply @var{frame}, they use the
985 @defun frame-pixel-height &optional frame
986 @defunx frame-pixel-width &optional frame
987 These functions return the height and width of the main display area
988 of @var{frame}, measured in pixels. If you don't supply @var{frame},
989 they use the selected frame. For a text-only terminal, the results are
990 in characters rather than pixels.
992 These values include the internal borders, and windows' scroll bars and
993 fringes (which belong to individual windows, not to the frame itself).
994 The exact value of the heights depends on the window-system and toolkit
995 in use. With Gtk+, the height does not include any tool bar or menu
996 bar. With the Motif or Lucid toolkits, it includes the tool bar but
997 not the menu bar. In a graphical version with no toolkit, it includes
998 both the tool bar and menu bar. For a text-only terminal, the result
999 includes the menu bar.
1002 @defun frame-char-height &optional frame
1003 @defunx frame-char-width &optional frame
1004 These functions return the height and width of a character in
1005 @var{frame}, measured in pixels. The values depend on the choice of
1006 font. If you don't supply @var{frame}, these functions use the selected
1010 @defun set-frame-size frame cols rows
1011 This function sets the size of @var{frame}, measured in characters;
1012 @var{cols} and @var{rows} specify the new width and height.
1014 To set the size based on values measured in pixels, use
1015 @code{frame-char-height} and @code{frame-char-width} to convert
1016 them to units of characters.
1019 @defun set-frame-height frame lines &optional pretend
1020 This function resizes @var{frame} to a height of @var{lines} lines. The
1021 sizes of existing windows in @var{frame} are altered proportionally to
1024 If @var{pretend} is non-@code{nil}, then Emacs displays @var{lines}
1025 lines of output in @var{frame}, but does not change its value for the
1026 actual height of the frame. This is only useful for a terminal frame.
1027 Using a smaller height than the terminal actually implements may be
1028 useful to reproduce behavior observed on a smaller screen, or if the
1029 terminal malfunctions when using its whole screen. Setting the frame
1030 height ``for real'' does not always work, because knowing the correct
1031 actual size may be necessary for correct cursor positioning on a
1035 @defun set-frame-width frame width &optional pretend
1036 This function sets the width of @var{frame}, measured in characters.
1037 The argument @var{pretend} has the same meaning as in
1038 @code{set-frame-height}.
1041 @findex set-screen-height
1042 @findex set-screen-width
1043 The older functions @code{set-screen-height} and
1044 @code{set-screen-width} were used to specify the height and width of the
1045 screen, in Emacs versions that did not support multiple frames. They
1046 are semi-obsolete, but still work; they apply to the selected frame.
1049 @subsection Geometry
1051 Here's how to examine the data in an X-style window geometry
1054 @defun x-parse-geometry geom
1055 @cindex geometry specification
1056 The function @code{x-parse-geometry} converts a standard X window
1057 geometry string to an alist that you can use as part of the argument to
1060 The alist describes which parameters were specified in @var{geom}, and
1061 gives the values specified for them. Each element looks like
1062 @code{(@var{parameter} . @var{value})}. The possible @var{parameter}
1063 values are @code{left}, @code{top}, @code{width}, and @code{height}.
1065 For the size parameters, the value must be an integer. The position
1066 parameter names @code{left} and @code{top} are not totally accurate,
1067 because some values indicate the position of the right or bottom edges
1068 instead. The @var{value} possibilities for the position parameters are:
1069 an integer, a list @code{(+ @var{pos})}, or a list @code{(- @var{pos})};
1070 as previously described (@pxref{Position Parameters}).
1075 (x-parse-geometry "35x70+0-0")
1076 @result{} ((height . 70) (width . 35)
1077 (top - 0) (left . 0))
1081 @node Terminal Parameters
1082 @section Terminal Parameters
1083 @cindex terminal parameters
1085 Each terminal has a list of associated parameters. These
1086 @dfn{terminal parameters} are mostly a convenient way of storage for
1087 terminal-local variables, but some terminal parameters have a special
1090 This section describes functions to read and change the parameter values
1091 of a terminal. They all accept as their argument either a terminal or
1092 a frame; the latter means use that frame's terminal. An argument of
1093 @code{nil} means the selected frame's terminal.
1095 @defun terminal-parameters &optional terminal
1096 This function returns an alist listing all the parameters of
1097 @var{terminal} and their values.
1100 @defun terminal-parameter terminal parameter
1101 This function returns the value of the parameter @var{parameter} (a
1102 symbol) of @var{terminal}. If @var{terminal} has no setting for
1103 @var{parameter}, this function returns @code{nil}.
1106 @defun set-terminal-parameter terminal parameter value
1107 This function sets the parameter @var{parm} of @var{terminal} to the
1108 specified @var{value}, and returns the previous value of that
1112 Here's a list of a few terminal parameters that have a special
1116 @item background-mode
1117 The classification of the terminal's background color, either
1118 @code{light} or @code{dark}.
1119 @item normal-erase-is-backspace
1120 Value is either 1 or 0, depending on whether
1121 @code{normal-erase-is-backspace-mode} is turned on or off on this
1122 terminal. @xref{DEL Does Not Delete,,, emacs, The Emacs Manual}.
1123 @item terminal-initted
1124 After the terminal is initialized, this is set to the
1125 terminal-specific initialization function.
1129 @section Frame Titles
1132 Every frame has a @code{name} parameter; this serves as the default
1133 for the frame title which window systems typically display at the top of
1134 the frame. You can specify a name explicitly by setting the @code{name}
1137 Normally you don't specify the name explicitly, and Emacs computes the
1138 frame name automatically based on a template stored in the variable
1139 @code{frame-title-format}. Emacs recomputes the name each time the
1140 frame is redisplayed.
1142 @defvar frame-title-format
1143 This variable specifies how to compute a name for a frame when you have
1144 not explicitly specified one. The variable's value is actually a mode
1145 line construct, just like @code{mode-line-format}, except that the
1146 @samp{%c} and @samp{%l} constructs are ignored. @xref{Mode Line
1150 @defvar icon-title-format
1151 This variable specifies how to compute the name for an iconified frame,
1152 when you have not explicitly specified the frame title. This title
1153 appears in the icon itself.
1156 @defvar multiple-frames
1157 This variable is set automatically by Emacs. Its value is @code{t} when
1158 there are two or more frames (not counting minibuffer-only frames or
1159 invisible frames). The default value of @code{frame-title-format} uses
1160 @code{multiple-frames} so as to put the buffer name in the frame title
1161 only when there is more than one frame.
1163 The value of this variable is not guaranteed to be accurate except
1164 while processing @code{frame-title-format} or
1165 @code{icon-title-format}.
1168 @node Deleting Frames
1169 @section Deleting Frames
1170 @cindex deleting frames
1172 Frames remain potentially visible until you explicitly @dfn{delete}
1173 them. A deleted frame cannot appear on the screen, but continues to
1174 exist as a Lisp object until there are no references to it.
1176 @deffn Command delete-frame &optional frame force
1177 @vindex delete-frame-functions
1178 This function deletes the frame @var{frame}. Unless @var{frame} is a
1179 tooltip, it first runs the hook @code{delete-frame-functions} (each
1180 function gets one argument, @var{frame}). By default, @var{frame} is
1183 A frame cannot be deleted if its minibuffer is used by other frames.
1184 Normally, you cannot delete a frame if all other frames are invisible,
1185 but if @var{force} is non-@code{nil}, then you are allowed to do so.
1188 @defun frame-live-p frame
1189 The function @code{frame-live-p} returns non-@code{nil} if the frame
1190 @var{frame} has not been deleted. The possible non-@code{nil} return
1191 values are like those of @code{framep}. @xref{Frames}.
1194 Some window managers provide a command to delete a window. These work
1195 by sending a special message to the program that operates the window.
1196 When Emacs gets one of these commands, it generates a
1197 @code{delete-frame} event, whose normal definition is a command that
1198 calls the function @code{delete-frame}. @xref{Misc Events}.
1200 @node Finding All Frames
1201 @section Finding All Frames
1202 @cindex frames, scanning all
1205 The function @code{frame-list} returns a list of all the live frames,
1206 i.e.@: those that have not been deleted. It is analogous to
1207 @code{buffer-list} for buffers, and includes frames on all terminals.
1208 The list that you get is newly created, so modifying the list doesn't
1209 have any effect on the internals of Emacs.
1212 @defun visible-frame-list
1213 This function returns a list of just the currently visible frames.
1214 @xref{Visibility of Frames}. (Terminal frames always count as
1215 ``visible,'' even though only the selected one is actually displayed.)
1218 @defun next-frame &optional frame minibuf
1219 The function @code{next-frame} lets you cycle conveniently through all
1220 the frames on the current display from an arbitrary starting point. It
1221 returns the ``next'' frame after @var{frame} in the cycle. If
1222 @var{frame} is omitted or @code{nil}, it defaults to the selected frame
1223 (@pxref{Input Focus}).
1225 The second argument, @var{minibuf}, says which frames to consider:
1229 Exclude minibuffer-only frames.
1230 @item @code{visible}
1231 Consider all visible frames.
1233 Consider all visible or iconified frames.
1235 Consider only the frames using that particular window as their
1238 Consider all frames.
1242 @defun previous-frame &optional frame minibuf
1243 Like @code{next-frame}, but cycles through all frames in the opposite
1247 See also @code{next-window} and @code{previous-window}, in @ref{Cyclic
1250 @node Frames and Windows
1251 @section Frames and Windows
1253 Each window is part of one and only one frame; you can get that frame
1254 with @code{window-frame}.
1256 @defun window-frame window
1257 This function returns the frame that @var{window} is on.
1260 All the non-minibuffer windows in a frame are arranged in a cyclic
1261 order. The order runs from the frame's top window, which is at the
1262 upper left corner, down and to the right, until it reaches the window at
1263 the lower right corner (always the minibuffer window, if the frame has
1264 one), and then it moves back to the top. @xref{Cyclic Window Ordering}.
1266 @defun frame-first-window &optional frame
1267 This returns the topmost, leftmost window of frame @var{frame}.
1268 If omitted or @code{nil}, @var{frame} defaults to the selected frame.
1271 At any time, exactly one window on any frame is @dfn{selected within the
1272 frame}. The significance of this designation is that selecting the
1273 frame also selects this window. Conversely, selecting a window for
1274 Emacs with @code{select-window} also makes that window selected within
1275 its frame. @xref{Selecting Windows}.
1277 @defun frame-selected-window &optional frame
1278 This function returns the window on @var{frame} that is selected
1279 within @var{frame}. If omitted or @code{nil}, @var{frame} defaults to
1283 @defun set-frame-selected-window frame window &optional norecord
1284 This sets the selected window of frame @var{frame} to @var{window}.
1285 If @var{frame} is @code{nil}, it operates on the selected frame. If
1286 @var{frame} is the selected frame, this makes @var{window} the
1287 selected window. This function returns @var{window}.
1289 Optional argument @var{norecord} non-@code{nil} means to neither change
1290 the order of recently selected windows nor the buffer list (@pxref{The
1294 Another function that (usually) returns one of the windows in a given
1295 frame is @code{minibuffer-window}. @xref{Definition of minibuffer-window}.
1297 @node Minibuffers and Frames
1298 @section Minibuffers and Frames
1300 Normally, each frame has its own minibuffer window at the bottom, which
1301 is used whenever that frame is selected. If the frame has a minibuffer,
1302 you can get it with @code{minibuffer-window} (@pxref{Definition of
1303 minibuffer-window}).
1305 However, you can also create a frame with no minibuffer. Such a frame
1306 must use the minibuffer window of some other frame. When you create the
1307 frame, you can specify explicitly the minibuffer window to use (in some
1308 other frame). If you don't, then the minibuffer is found in the frame
1309 which is the value of the variable @code{default-minibuffer-frame}. Its
1310 value should be a frame that does have a minibuffer.
1312 If you use a minibuffer-only frame, you might want that frame to raise
1313 when you enter the minibuffer. If so, set the variable
1314 @code{minibuffer-auto-raise} to @code{t}. @xref{Raising and Lowering}.
1316 @defvar default-minibuffer-frame
1317 This variable specifies the frame to use for the minibuffer window, by
1318 default. It does not affect existing frames. It is always local to
1319 the current terminal and cannot be buffer-local. @xref{Multiple
1324 @section Input Focus
1326 @c @cindex selected frame Duplicates selected-frame
1328 At any time, one frame in Emacs is the @dfn{selected frame}. The selected
1329 window always resides on the selected frame.
1331 When Emacs displays its frames on several terminals (@pxref{Multiple
1332 Terminals}), each terminal has its own selected frame. But only one
1333 of these is ``@emph{the} selected frame'': it's the frame that belongs
1334 to the terminal from which the most recent input came. That is, when
1335 Emacs runs a command that came from a certain terminal, the selected
1336 frame is the one of that terminal. Since Emacs runs only a single
1337 command at any given time, it needs to consider only one selected
1338 frame at a time; this frame is what we call @dfn{the selected frame}
1339 in this manual. The display on which the selected frame is shown is
1340 the @dfn{selected frame's display}.
1342 @defun selected-frame
1343 This function returns the selected frame.
1346 Some window systems and window managers direct keyboard input to the
1347 window object that the mouse is in; others require explicit clicks or
1348 commands to @dfn{shift the focus} to various window objects. Either
1349 way, Emacs automatically keeps track of which frame has the focus. To
1350 explicitly switch to a different frame from a Lisp function, call
1351 @code{select-frame-set-input-focus}.
1353 Lisp programs can also switch frames ``temporarily'' by calling the
1354 function @code{select-frame}. This does not alter the window system's
1355 concept of focus; rather, it escapes from the window manager's control
1356 until that control is somehow reasserted.
1358 When using a text-only terminal, only one frame can be displayed at a
1359 time on the terminal, so after a call to @code{select-frame}, the next
1360 redisplay actually displays the newly selected frame. This frame
1361 remains selected until a subsequent call to @code{select-frame}. Each
1362 terminal frame has a number which appears in the mode line before the
1363 buffer name (@pxref{Mode Line Variables}).
1365 @defun select-frame-set-input-focus frame
1366 This function selects @var{frame}, raises it (should it happen to be
1367 obscured by other frames) and tries to give it the X server's focus. On
1368 a text-only terminal, the next redisplay displays the new frame on the
1369 entire terminal screen. The return value of this function is not
1373 @c ??? This is not yet implemented properly.
1374 @defun select-frame frame &optional norecord
1375 This function selects frame @var{frame}, temporarily disregarding the
1376 focus of the X server if any. The selection of @var{frame} lasts until
1377 the next time the user does something to select a different frame, or
1378 until the next time this function is called. (If you are using a
1379 window system, the previously selected frame may be restored as the
1380 selected frame after return to the command loop, because it still may
1381 have the window system's input focus.)
1383 The specified @var{frame} becomes the selected frame, as explained
1384 above, and the terminal that @var{frame} is on becomes the selected
1385 terminal. The window selected within @var{frame} becomes the selected
1386 window. This function returns @var{frame}, or @code{nil} if @var{frame}
1389 Optional argument @var{norecord} non-@code{nil} means to neither change
1390 the order of recently selected windows nor the buffer list. @xref{The
1393 In general, you should never use @code{select-frame} in a way that could
1394 switch to a different terminal without switching back when you're done.
1397 Emacs cooperates with the window system by arranging to select frames as
1398 the server and window manager request. It does so by generating a
1399 special kind of input event, called a @dfn{focus} event, when
1400 appropriate. The command loop handles a focus event by calling
1401 @code{handle-switch-frame}. @xref{Focus Events}.
1403 @deffn Command handle-switch-frame frame
1404 This function handles a focus event by selecting frame @var{frame}.
1406 Focus events normally do their job by invoking this command.
1407 Don't call it for any other reason.
1410 @defun redirect-frame-focus frame &optional focus-frame
1411 This function redirects focus from @var{frame} to @var{focus-frame}.
1412 This means that @var{focus-frame} will receive subsequent keystrokes and
1413 events intended for @var{frame}. After such an event, the value of
1414 @code{last-event-frame} will be @var{focus-frame}. Also, switch-frame
1415 events specifying @var{frame} will instead select @var{focus-frame}.
1417 If @var{focus-frame} is omitted or @code{nil}, that cancels any existing
1418 redirection for @var{frame}, which therefore once again receives its own
1421 One use of focus redirection is for frames that don't have minibuffers.
1422 These frames use minibuffers on other frames. Activating a minibuffer
1423 on another frame redirects focus to that frame. This puts the focus on
1424 the minibuffer's frame, where it belongs, even though the mouse remains
1425 in the frame that activated the minibuffer.
1427 Selecting a frame can also change focus redirections. Selecting frame
1428 @code{bar}, when @code{foo} had been selected, changes any redirections
1429 pointing to @code{foo} so that they point to @code{bar} instead. This
1430 allows focus redirection to work properly when the user switches from
1431 one frame to another using @code{select-window}.
1433 This means that a frame whose focus is redirected to itself is treated
1434 differently from a frame whose focus is not redirected.
1435 @code{select-frame} affects the former but not the latter.
1437 The redirection lasts until @code{redirect-frame-focus} is called to
1441 @defopt focus-follows-mouse
1442 This option is how you inform Emacs whether the window manager transfers
1443 focus when the user moves the mouse. Non-@code{nil} says that it does.
1444 When this is so, the command @code{other-frame} moves the mouse to a
1445 position consistent with the new selected frame.
1448 @node Visibility of Frames
1449 @section Visibility of Frames
1450 @cindex visible frame
1451 @cindex invisible frame
1452 @cindex iconified frame
1453 @cindex frame visibility
1455 A window frame may be @dfn{visible}, @dfn{invisible}, or
1456 @dfn{iconified}. If it is visible, you can see its contents, unless
1457 other windows cover it. If it is iconified, the frame's contents do
1458 not appear on the screen, but an icon does. (Note: because of the
1459 way in which some window managers implement the concept of multiple
1460 workspaces, or desktops, all frames on other workspaces may appear to
1461 Emacs to be iconified.) If the frame is invisible, it doesn't show on
1462 the screen, not even as an icon.
1464 Visibility is meaningless for terminal frames, since only the selected
1465 one is actually displayed in any case.
1467 @deffn Command make-frame-visible &optional frame
1468 This function makes frame @var{frame} visible. If you omit
1469 @var{frame}, it makes the selected frame visible. This does not raise
1470 the frame, but you can do that with @code{raise-frame} if you wish
1471 (@pxref{Raising and Lowering}).
1474 @deffn Command make-frame-invisible &optional frame force
1475 This function makes frame @var{frame} invisible. If you omit
1476 @var{frame}, it makes the selected frame invisible.
1478 Unless @var{force} is non-@code{nil}, this function refuses to make
1479 @var{frame} invisible if all other frames are invisible..
1482 @deffn Command iconify-frame &optional frame
1483 This function iconifies frame @var{frame}. If you omit @var{frame}, it
1484 iconifies the selected frame.
1487 @defun frame-visible-p frame
1488 This returns the visibility status of frame @var{frame}. The value is
1489 @code{t} if @var{frame} is visible, @code{nil} if it is invisible, and
1490 @code{icon} if it is iconified.
1492 On a text-only terminal, all frames are considered visible, whether
1493 they are currently being displayed or not, and this function returns
1494 @code{t} for all frames.
1497 The visibility status of a frame is also available as a frame
1498 parameter. You can read or change it as such. @xref{Management
1501 The user can iconify and deiconify frames with the window manager.
1502 This happens below the level at which Emacs can exert any control, but
1503 Emacs does provide events that you can use to keep track of such
1504 changes. @xref{Misc Events}.
1506 @node Raising and Lowering
1507 @section Raising and Lowering Frames
1509 Most window systems use a desktop metaphor. Part of this metaphor is
1510 the idea that windows are stacked in a notional third dimension
1511 perpendicular to the screen surface, and thus ordered from ``highest''
1512 to ``lowest.'' Where two windows overlap, the one higher up covers
1513 the one underneath. Even a window at the bottom of the stack can be
1514 seen if no other window overlaps it.
1516 @c @cindex raising a frame redundant with raise-frame
1517 @cindex lowering a frame
1518 A window's place in this ordering is not fixed; in fact, users tend
1519 to change the order frequently. @dfn{Raising} a window means moving
1520 it ``up,'' to the top of the stack. @dfn{Lowering} a window means
1521 moving it to the bottom of the stack. This motion is in the notional
1522 third dimension only, and does not change the position of the window
1525 With Emacs, frames constitute the windows in the metaphor sketched
1526 above. You can raise and lower frames using these functions:
1528 @deffn Command raise-frame &optional frame
1529 This function raises frame @var{frame} (default, the selected frame).
1530 If @var{frame} is invisible or iconified, this makes it visible.
1533 @deffn Command lower-frame &optional frame
1534 This function lowers frame @var{frame} (default, the selected frame).
1537 @defopt minibuffer-auto-raise
1538 If this is non-@code{nil}, activation of the minibuffer raises the frame
1539 that the minibuffer window is in.
1542 You can also enable auto-raise (raising automatically when a frame is
1543 selected) or auto-lower (lowering automatically when it is deselected)
1544 for any frame using frame parameters. @xref{Management Parameters}.
1546 @node Frame Configurations
1547 @section Frame Configurations
1548 @cindex frame configuration
1550 A @dfn{frame configuration} records the current arrangement of frames,
1551 all their properties, and the window configuration of each one.
1552 (@xref{Window Configurations}.)
1554 @defun current-frame-configuration
1555 This function returns a frame configuration list that describes
1556 the current arrangement of frames and their contents.
1559 @defun set-frame-configuration configuration &optional nodelete
1560 This function restores the state of frames described in
1561 @var{configuration}. However, this function does not restore deleted
1564 Ordinarily, this function deletes all existing frames not listed in
1565 @var{configuration}. But if @var{nodelete} is non-@code{nil}, the
1566 unwanted frames are iconified instead.
1569 @node Mouse Tracking
1570 @section Mouse Tracking
1571 @cindex mouse tracking
1572 @c @cindex tracking the mouse Duplicates track-mouse
1574 Sometimes it is useful to @dfn{track} the mouse, which means to display
1575 something to indicate where the mouse is and move the indicator as the
1576 mouse moves. For efficient mouse tracking, you need a way to wait until
1577 the mouse actually moves.
1579 The convenient way to track the mouse is to ask for events to represent
1580 mouse motion. Then you can wait for motion by waiting for an event. In
1581 addition, you can easily handle any other sorts of events that may
1582 occur. That is useful, because normally you don't want to track the
1583 mouse forever---only until some other event, such as the release of a
1586 @defspec track-mouse body@dots{}
1587 This special form executes @var{body}, with generation of mouse motion
1588 events enabled. Typically, @var{body} would use @code{read-event} to
1589 read the motion events and modify the display accordingly. @xref{Motion
1590 Events}, for the format of mouse motion events.
1592 The value of @code{track-mouse} is that of the last form in @var{body}.
1593 You should design @var{body} to return when it sees the up-event that
1594 indicates the release of the button, or whatever kind of event means
1595 it is time to stop tracking.
1598 The usual purpose of tracking mouse motion is to indicate on the screen
1599 the consequences of pushing or releasing a button at the current
1602 In many cases, you can avoid the need to track the mouse by using
1603 the @code{mouse-face} text property (@pxref{Special Properties}).
1604 That works at a much lower level and runs more smoothly than
1605 Lisp-level mouse tracking.
1608 @c These are not implemented yet.
1610 These functions change the screen appearance instantaneously. The
1611 effect is transient, only until the next ordinary Emacs redisplay. That
1612 is OK for mouse tracking, since it doesn't make sense for mouse tracking
1613 to change the text, and the body of @code{track-mouse} normally reads
1614 the events itself and does not do redisplay.
1616 @defun x-contour-region window beg end
1617 This function draws lines to make a box around the text from @var{beg}
1618 to @var{end}, in window @var{window}.
1621 @defun x-uncontour-region window beg end
1622 This function erases the lines that would make a box around the text
1623 from @var{beg} to @var{end}, in window @var{window}. Use it to remove
1624 a contour that you previously made by calling @code{x-contour-region}.
1627 @defun x-draw-rectangle frame left top right bottom
1628 This function draws a hollow rectangle on frame @var{frame} with the
1629 specified edge coordinates, all measured in pixels from the inside top
1630 left corner. It uses the cursor color, the one used for indicating the
1634 @defun x-erase-rectangle frame left top right bottom
1635 This function erases a hollow rectangle on frame @var{frame} with the
1636 specified edge coordinates, all measured in pixels from the inside top
1637 left corner. Erasure means redrawing the text and background that
1638 normally belong in the specified rectangle.
1642 @node Mouse Position
1643 @section Mouse Position
1644 @cindex mouse position
1645 @cindex position of mouse
1647 The functions @code{mouse-position} and @code{set-mouse-position}
1648 give access to the current position of the mouse.
1650 @defun mouse-position
1651 This function returns a description of the position of the mouse. The
1652 value looks like @code{(@var{frame} @var{x} . @var{y})}, where @var{x}
1653 and @var{y} are integers giving the position in characters relative to
1654 the top left corner of the inside of @var{frame}.
1657 @defvar mouse-position-function
1658 If non-@code{nil}, the value of this variable is a function for
1659 @code{mouse-position} to call. @code{mouse-position} calls this
1660 function just before returning, with its normal return value as the
1661 sole argument, and it returns whatever this function returns to it.
1663 This abnormal hook exists for the benefit of packages like
1664 @file{xt-mouse.el} that need to do mouse handling at the Lisp level.
1667 @defun set-mouse-position frame x y
1668 This function @dfn{warps the mouse} to position @var{x}, @var{y} in
1669 frame @var{frame}. The arguments @var{x} and @var{y} are integers,
1670 giving the position in characters relative to the top left corner of the
1671 inside of @var{frame}. If @var{frame} is not visible, this function
1672 does nothing. The return value is not significant.
1675 @defun mouse-pixel-position
1676 This function is like @code{mouse-position} except that it returns
1677 coordinates in units of pixels rather than units of characters.
1680 @defun set-mouse-pixel-position frame x y
1681 This function warps the mouse like @code{set-mouse-position} except that
1682 @var{x} and @var{y} are in units of pixels rather than units of
1683 characters. These coordinates are not required to be within the frame.
1685 If @var{frame} is not visible, this function does nothing. The return
1686 value is not significant.
1692 @section Pop-Up Menus
1694 When using a window system, a Lisp program can pop up a menu so that
1695 the user can choose an alternative with the mouse.
1697 @defun x-popup-menu position menu
1698 This function displays a pop-up menu and returns an indication of
1699 what selection the user makes.
1701 The argument @var{position} specifies where on the screen to put the
1702 top left corner of the menu. It can be either a mouse button event
1703 (which says to put the menu where the user actuated the button) or a
1707 ((@var{xoffset} @var{yoffset}) @var{window})
1711 where @var{xoffset} and @var{yoffset} are coordinates, measured in
1712 pixels, counting from the top left corner of @var{window}. @var{window}
1713 may be a window or a frame.
1715 If @var{position} is @code{t}, it means to use the current mouse
1716 position. If @var{position} is @code{nil}, it means to precompute the
1717 key binding equivalents for the keymaps specified in @var{menu},
1718 without actually displaying or popping up the menu.
1720 The argument @var{menu} says what to display in the menu. It can be a
1721 keymap or a list of keymaps (@pxref{Menu Keymaps}). In this case, the
1722 return value is the list of events corresponding to the user's choice.
1723 (This list has more than one element if the choice occurred in a
1724 submenu.) Note that @code{x-popup-menu} does not actually execute the
1725 command bound to that sequence of events.
1727 Alternatively, @var{menu} can have the following form:
1730 (@var{title} @var{pane1} @var{pane2}...)
1734 where each pane is a list of form
1737 (@var{title} @var{item1} @var{item2}...)
1740 Each item should normally be a cons cell @code{(@var{line} . @var{value})},
1741 where @var{line} is a string, and @var{value} is the value to return if
1742 that @var{line} is chosen. An item can also be a string; this makes a
1743 non-selectable line in the menu.
1745 If the user gets rid of the menu without making a valid choice, for
1746 instance by clicking the mouse away from a valid choice or by typing
1747 keyboard input, then this normally results in a quit and
1748 @code{x-popup-menu} does not return. But if @var{position} is a mouse
1749 button event (indicating that the user invoked the menu with the
1750 mouse) then no quit occurs and @code{x-popup-menu} returns @code{nil}.
1753 @strong{Usage note:} Don't use @code{x-popup-menu} to display a menu
1754 if you could do the job with a prefix key defined with a menu keymap.
1755 If you use a menu keymap to implement a menu, @kbd{C-h c} and @kbd{C-h
1756 a} can see the individual items in that menu and provide help for them.
1757 If instead you implement the menu by defining a command that calls
1758 @code{x-popup-menu}, the help facilities cannot know what happens inside
1759 that command, so they cannot give any help for the menu's items.
1761 The menu bar mechanism, which lets you switch between submenus by
1762 moving the mouse, cannot look within the definition of a command to see
1763 that it calls @code{x-popup-menu}. Therefore, if you try to implement a
1764 submenu using @code{x-popup-menu}, it cannot work with the menu bar in
1765 an integrated fashion. This is why all menu bar submenus are
1766 implemented with menu keymaps within the parent menu, and never with
1767 @code{x-popup-menu}. @xref{Menu Bar}.
1769 If you want a menu bar submenu to have contents that vary, you should
1770 still use a menu keymap to implement it. To make the contents vary, add
1771 a hook function to @code{menu-bar-update-hook} to update the contents of
1772 the menu keymap as necessary.
1775 @section Dialog Boxes
1776 @cindex dialog boxes
1778 A dialog box is a variant of a pop-up menu---it looks a little
1779 different, it always appears in the center of a frame, and it has just
1780 one level and one or more buttons. The main use of dialog boxes is
1781 for asking questions that the user can answer with ``yes,'' ``no,''
1782 and a few other alternatives. With a single button, they can also
1783 force the user to acknowledge important information. The functions
1784 @code{y-or-n-p} and @code{yes-or-no-p} use dialog boxes instead of the
1785 keyboard, when called from commands invoked by mouse clicks.
1787 @defun x-popup-dialog position contents &optional header
1788 This function displays a pop-up dialog box and returns an indication of
1789 what selection the user makes. The argument @var{contents} specifies
1790 the alternatives to offer; it has this format:
1793 (@var{title} (@var{string} . @var{value})@dots{})
1797 which looks like the list that specifies a single pane for
1798 @code{x-popup-menu}.
1800 The return value is @var{value} from the chosen alternative.
1802 As for @code{x-popup-menu}, an element of the list may be just a
1803 string instead of a cons cell @code{(@var{string} . @var{value})}.
1804 That makes a box that cannot be selected.
1806 If @code{nil} appears in the list, it separates the left-hand items from
1807 the right-hand items; items that precede the @code{nil} appear on the
1808 left, and items that follow the @code{nil} appear on the right. If you
1809 don't include a @code{nil} in the list, then approximately half the
1810 items appear on each side.
1812 Dialog boxes always appear in the center of a frame; the argument
1813 @var{position} specifies which frame. The possible values are as in
1814 @code{x-popup-menu}, but the precise coordinates or the individual
1815 window don't matter; only the frame matters.
1817 If @var{header} is non-@code{nil}, the frame title for the box is
1818 @samp{Information}, otherwise it is @samp{Question}. The former is used
1819 for @code{message-box} (@pxref{message-box}).
1821 In some configurations, Emacs cannot display a real dialog box; so
1822 instead it displays the same items in a pop-up menu in the center of the
1825 If the user gets rid of the dialog box without making a valid choice,
1826 for instance using the window manager, then this produces a quit and
1827 @code{x-popup-dialog} does not return.
1831 @section Pointer Shape
1832 @cindex pointer shape
1833 @cindex mouse pointer shape
1835 You can specify the mouse pointer style for particular text or
1836 images using the @code{pointer} text property, and for images with the
1837 @code{:pointer} and @code{:map} image properties. The values you can
1838 use in these properties are @code{text} (or @code{nil}), @code{arrow},
1839 @code{hand}, @code{vdrag}, @code{hdrag}, @code{modeline}, and
1840 @code{hourglass}. @code{text} stands for the usual mouse pointer
1841 style used over text.
1843 Over void parts of the window (parts that do not correspond to any
1844 of the buffer contents), the mouse pointer usually uses the
1845 @code{arrow} style, but you can specify a different style (one of
1846 those above) by setting @code{void-text-area-pointer}.
1848 @defvar void-text-area-pointer
1849 This variable specifies the mouse pointer style for void text areas.
1850 These include the areas after the end of a line or below the last line
1851 in the buffer. The default is to use the @code{arrow} (non-text)
1855 When using X, you can specify what the @code{text} pointer style
1856 really looks like by setting the variable @code{x-pointer-shape}.
1858 @defvar x-pointer-shape
1859 This variable specifies the pointer shape to use ordinarily in the
1860 Emacs frame, for the @code{text} pointer style.
1863 @defvar x-sensitive-text-pointer-shape
1864 This variable specifies the pointer shape to use when the mouse
1865 is over mouse-sensitive text.
1868 These variables affect newly created frames. They do not normally
1869 affect existing frames; however, if you set the mouse color of a
1870 frame, that also installs the current value of those two variables.
1871 @xref{Font and Color Parameters}.
1873 The values you can use, to specify either of these pointer shapes, are
1874 defined in the file @file{lisp/term/x-win.el}. Use @kbd{M-x apropos
1875 @key{RET} x-pointer @key{RET}} to see a list of them.
1877 @node Window System Selections
1878 @section Window System Selections
1879 @cindex selection (for window systems)
1881 The X server records a set of @dfn{selections} which permit transfer of
1882 data between application programs. The various selections are
1883 distinguished by @dfn{selection types}, represented in Emacs by
1884 symbols. X clients including Emacs can read or set the selection for
1887 @deffn Command x-set-selection type data
1888 This function sets a ``selection'' in the X server. It takes two
1889 arguments: a selection type @var{type}, and the value to assign to it,
1890 @var{data}. If @var{data} is @code{nil}, it means to clear out the
1891 selection. Otherwise, @var{data} may be a string, a symbol, an integer
1892 (or a cons of two integers or list of two integers), an overlay, or a
1893 cons of two markers pointing to the same buffer. An overlay or a pair
1894 of markers stands for text in the overlay or between the markers.
1896 The argument @var{data} may also be a vector of valid non-vector
1899 Each possible @var{type} has its own selection value, which changes
1900 independently. The usual values of @var{type} are @code{PRIMARY},
1901 @code{SECONDARY} and @code{CLIPBOARD}; these are symbols with upper-case
1902 names, in accord with X Window System conventions. If @var{type} is
1903 @code{nil}, that stands for @code{PRIMARY}.
1905 This function returns @var{data}.
1908 @defun x-get-selection &optional type data-type
1909 This function accesses selections set up by Emacs or by other X
1910 clients. It takes two optional arguments, @var{type} and
1911 @var{data-type}. The default for @var{type}, the selection type, is
1914 The @var{data-type} argument specifies the form of data conversion to
1915 use, to convert the raw data obtained from another X client into Lisp
1916 data. Meaningful values include @code{TEXT}, @code{STRING},
1917 @code{UTF8_STRING}, @code{TARGETS}, @code{LENGTH}, @code{DELETE},
1918 @code{FILE_NAME}, @code{CHARACTER_POSITION}, @code{NAME},
1919 @code{LINE_NUMBER}, @code{COLUMN_NUMBER}, @code{OWNER_OS},
1920 @code{HOST_NAME}, @code{USER}, @code{CLASS}, @code{ATOM}, and
1921 @code{INTEGER}. (These are symbols with upper-case names in accord
1922 with X conventions.) The default for @var{data-type} is
1927 The X server also has a set of eight numbered @dfn{cut buffers} which can
1928 store text or other data being moved between applications. Cut buffers
1929 are considered obsolete, but Emacs supports them for the sake of X
1930 clients that still use them. Cut buffers are numbered from 0 to 7.
1932 @defun x-get-cut-buffer &optional n
1933 This function returns the contents of cut buffer number @var{n}.
1934 If omitted @var{n} defaults to 0.
1937 @defun x-set-cut-buffer string &optional push
1938 @anchor{Definition of x-set-cut-buffer}
1939 This function stores @var{string} into the first cut buffer (cut buffer
1940 0). If @var{push} is @code{nil}, only the first cut buffer is changed.
1941 If @var{push} is non-@code{nil}, that says to move the values down
1942 through the series of cut buffers, much like the way successive kills in
1943 Emacs move down the kill ring. In other words, the previous value of
1944 the first cut buffer moves into the second cut buffer, and the second to
1945 the third, and so on through all eight cut buffers.
1948 @defopt selection-coding-system
1949 This variable specifies the coding system to use when reading and
1950 writing selections or the clipboard. @xref{Coding
1951 Systems}. The default is @code{compound-text-with-extensions}, which
1952 converts to the text representation that X11 normally uses.
1955 @cindex clipboard support (for MS-Windows)
1956 When Emacs runs on MS-Windows, it does not implement X selections in
1957 general, but it does support the clipboard. @code{x-get-selection}
1958 and @code{x-set-selection} on MS-Windows support the text data type
1959 only; if the clipboard holds other types of data, Emacs treats the
1962 @defopt x-select-enable-clipboard
1963 If this is non-@code{nil}, the Emacs yank functions consult the
1964 clipboard before the primary selection, and the kill functions store in
1965 the clipboard as well as the primary selection. Otherwise they do not
1966 access the clipboard at all. The default is @code{nil} on most systems,
1967 but @code{t} on MS-Windows.
1971 @section Drag and Drop
1973 @vindex x-dnd-test-function
1974 @vindex x-dnd-known-types
1975 When a user drags something from another application over Emacs, that other
1976 application expects Emacs to tell it if Emacs can handle the data that is
1977 dragged. The variable @code{x-dnd-test-function} is used by Emacs to determine
1978 what to reply. The default value is @code{x-dnd-default-test-function}
1979 which accepts drops if the type of the data to be dropped is present in
1980 @code{x-dnd-known-types}. You can customize @code{x-dnd-test-function} and/or
1981 @code{x-dnd-known-types} if you want Emacs to accept or reject drops based
1982 on some other criteria.
1984 @vindex x-dnd-types-alist
1985 If you want to change the way Emacs handles drop of different types
1986 or add a new type, customize @code{x-dnd-types-alist}. This requires
1987 detailed knowledge of what types other applications use for drag and
1990 @vindex dnd-protocol-alist
1991 When an URL is dropped on Emacs it may be a file, but it may also be
1992 another URL type (ftp, http, etc.). Emacs first checks
1993 @code{dnd-protocol-alist} to determine what to do with the URL. If
1994 there is no match there and if @code{browse-url-browser-function} is
1995 an alist, Emacs looks for a match there. If no match is found the
1996 text for the URL is inserted. If you want to alter Emacs behavior,
1997 you can customize these variables.
2000 @section Color Names
2003 @cindex specify color
2004 @cindex numerical RGB color specification
2005 A color name is text (usually in a string) that specifies a color.
2006 Symbolic names such as @samp{black}, @samp{white}, @samp{red}, etc.,
2007 are allowed; use @kbd{M-x list-colors-display} to see a list of
2008 defined names. You can also specify colors numerically in forms such
2009 as @samp{#@var{rgb}} and @samp{RGB:@var{r}/@var{g}/@var{b}}, where
2010 @var{r} specifies the red level, @var{g} specifies the green level,
2011 and @var{b} specifies the blue level. You can use either one, two,
2012 three, or four hex digits for @var{r}; then you must use the same
2013 number of hex digits for all @var{g} and @var{b} as well, making
2014 either 3, 6, 9 or 12 hex digits in all. (See the documentation of the
2015 X Window System for more details about numerical RGB specification of
2018 These functions provide a way to determine which color names are
2019 valid, and what they look like. In some cases, the value depends on the
2020 @dfn{selected frame}, as described below; see @ref{Input Focus}, for the
2021 meaning of the term ``selected frame.''
2023 To read user input of color names with completion, use
2024 @code{read-color} (@pxref{High-Level Completion, read-color}).
2026 @defun color-defined-p color &optional frame
2027 This function reports whether a color name is meaningful. It returns
2028 @code{t} if so; otherwise, @code{nil}. The argument @var{frame} says
2029 which frame's display to ask about; if @var{frame} is omitted or
2030 @code{nil}, the selected frame is used.
2032 Note that this does not tell you whether the display you are using
2033 really supports that color. When using X, you can ask for any defined
2034 color on any kind of display, and you will get some result---typically,
2035 the closest it can do. To determine whether a frame can really display
2036 a certain color, use @code{color-supported-p} (see below).
2038 @findex x-color-defined-p
2039 This function used to be called @code{x-color-defined-p},
2040 and that name is still supported as an alias.
2043 @defun defined-colors &optional frame
2044 This function returns a list of the color names that are defined
2045 and supported on frame @var{frame} (default, the selected frame).
2046 If @var{frame} does not support colors, the value is @code{nil}.
2048 @findex x-defined-colors
2049 This function used to be called @code{x-defined-colors},
2050 and that name is still supported as an alias.
2053 @defun color-supported-p color &optional frame background-p
2054 This returns @code{t} if @var{frame} can really display the color
2055 @var{color} (or at least something close to it). If @var{frame} is
2056 omitted or @code{nil}, the question applies to the selected frame.
2058 Some terminals support a different set of colors for foreground and
2059 background. If @var{background-p} is non-@code{nil}, that means you are
2060 asking whether @var{color} can be used as a background; otherwise you
2061 are asking whether it can be used as a foreground.
2063 The argument @var{color} must be a valid color name.
2066 @defun color-gray-p color &optional frame
2067 This returns @code{t} if @var{color} is a shade of gray, as defined on
2068 @var{frame}'s display. If @var{frame} is omitted or @code{nil}, the
2069 question applies to the selected frame. If @var{color} is not a valid
2070 color name, this function returns @code{nil}.
2073 @defun color-values color &optional frame
2075 This function returns a value that describes what @var{color} should
2076 ideally look like on @var{frame}. If @var{color} is defined, the
2077 value is a list of three integers, which give the amount of red, the
2078 amount of green, and the amount of blue. Each integer ranges in
2079 principle from 0 to 65535, but some displays may not use the full
2080 range. This three-element list is called the @dfn{rgb values} of the
2083 If @var{color} is not defined, the value is @code{nil}.
2086 (color-values "black")
2088 (color-values "white")
2089 @result{} (65280 65280 65280)
2090 (color-values "red")
2091 @result{} (65280 0 0)
2092 (color-values "pink")
2093 @result{} (65280 49152 51968)
2094 (color-values "hungry")
2098 The color values are returned for @var{frame}'s display. If
2099 @var{frame} is omitted or @code{nil}, the information is returned for
2100 the selected frame's display. If the frame cannot display colors, the
2101 value is @code{nil}.
2103 @findex x-color-values
2104 This function used to be called @code{x-color-values},
2105 and that name is still supported as an alias.
2108 @node Text Terminal Colors
2109 @section Text Terminal Colors
2110 @cindex colors on text-only terminals
2112 Text-only terminals usually support only a small number of colors,
2113 and the computer uses small integers to select colors on the terminal.
2114 This means that the computer cannot reliably tell what the selected
2115 color looks like; instead, you have to inform your application which
2116 small integers correspond to which colors. However, Emacs does know
2117 the standard set of colors and will try to use them automatically.
2119 The functions described in this section control how terminal colors
2122 Several of these functions use or return @dfn{rgb values}, described
2123 in @ref{Color Names}.
2125 These functions accept a display (either a frame or the name of a
2126 terminal) as an optional argument. We hope in the future to make
2127 Emacs support different colors on different text-only terminals; then
2128 this argument will specify which terminal to operate on (the default
2129 being the selected frame's terminal; @pxref{Input Focus}). At
2130 present, though, the @var{frame} argument has no effect.
2132 @defun tty-color-define name number &optional rgb frame
2133 This function associates the color name @var{name} with
2134 color number @var{number} on the terminal.
2136 The optional argument @var{rgb}, if specified, is an rgb value, a list
2137 of three numbers that specify what the color actually looks like.
2138 If you do not specify @var{rgb}, then this color cannot be used by
2139 @code{tty-color-approximate} to approximate other colors, because
2140 Emacs will not know what it looks like.
2143 @defun tty-color-clear &optional frame
2144 This function clears the table of defined colors for a text-only terminal.
2147 @defun tty-color-alist &optional frame
2148 This function returns an alist recording the known colors supported by a
2151 Each element has the form @code{(@var{name} @var{number} . @var{rgb})}
2152 or @code{(@var{name} @var{number})}. Here, @var{name} is the color
2153 name, @var{number} is the number used to specify it to the terminal.
2154 If present, @var{rgb} is a list of three color values (for red, green,
2155 and blue) that says what the color actually looks like.
2158 @defun tty-color-approximate rgb &optional frame
2159 This function finds the closest color, among the known colors
2160 supported for @var{display}, to that described by the rgb value
2161 @var{rgb} (a list of color values). The return value is an element of
2162 @code{tty-color-alist}.
2165 @defun tty-color-translate color &optional frame
2166 This function finds the closest color to @var{color} among the known
2167 colors supported for @var{display} and returns its index (an integer).
2168 If the name @var{color} is not defined, the value is @code{nil}.
2172 @section X Resources
2174 This section describes some of the functions and variables for
2175 querying and using X resources, or their equivalent on your operating
2176 system. @xref{X Resources,, X Resources, emacs, The GNU Emacs
2177 Manual}, for more information about X resources.
2179 @defun x-get-resource attribute class &optional component subclass
2180 The function @code{x-get-resource} retrieves a resource value from the X
2181 Window defaults database.
2183 Resources are indexed by a combination of a @dfn{key} and a @dfn{class}.
2184 This function searches using a key of the form
2185 @samp{@var{instance}.@var{attribute}} (where @var{instance} is the name
2186 under which Emacs was invoked), and using @samp{Emacs.@var{class}} as
2189 The optional arguments @var{component} and @var{subclass} add to the key
2190 and the class, respectively. You must specify both of them or neither.
2191 If you specify them, the key is
2192 @samp{@var{instance}.@var{component}.@var{attribute}}, and the class is
2193 @samp{Emacs.@var{class}.@var{subclass}}.
2196 @defvar x-resource-class
2197 This variable specifies the application name that @code{x-get-resource}
2198 should look up. The default value is @code{"Emacs"}. You can examine X
2199 resources for application names other than ``Emacs'' by binding this
2200 variable to some other string, around a call to @code{x-get-resource}.
2203 @defvar x-resource-name
2204 This variable specifies the instance name that @code{x-get-resource}
2205 should look up. The default value is the name Emacs was invoked with,
2206 or the value specified with the @samp{-name} or @samp{-rn} switches.
2209 To illustrate some of the above, suppose that you have the line:
2212 xterm.vt100.background: yellow
2216 in your X resources file (whose name is usually @file{~/.Xdefaults}
2217 or @file{~/.Xresources}). Then:
2221 (let ((x-resource-class "XTerm") (x-resource-name "xterm"))
2222 (x-get-resource "vt100.background" "VT100.Background"))
2226 (let ((x-resource-class "XTerm") (x-resource-name "xterm"))
2227 (x-get-resource "background" "VT100" "vt100" "Background"))
2232 @defvar inhibit-x-resources
2233 If this variable is non-@code{nil}, Emacs does not look up X
2234 resources, and X resources do not have any effect when creating new
2238 @node Display Feature Testing
2239 @section Display Feature Testing
2240 @cindex display feature testing
2242 The functions in this section describe the basic capabilities of a
2243 particular display. Lisp programs can use them to adapt their behavior
2244 to what the display can do. For example, a program that ordinarily uses
2245 a popup menu could use the minibuffer if popup menus are not supported.
2247 The optional argument @var{display} in these functions specifies which
2248 display to ask the question about. It can be a display name, a frame
2249 (which designates the display that frame is on), or @code{nil} (which
2250 refers to the selected frame's display, @pxref{Input Focus}).
2252 @xref{Color Names}, @ref{Text Terminal Colors}, for other functions to
2253 obtain information about displays.
2255 @defun display-popup-menus-p &optional display
2256 This function returns @code{t} if popup menus are supported on
2257 @var{display}, @code{nil} if not. Support for popup menus requires that
2258 the mouse be available, since the user cannot choose menu items without
2262 @defun display-graphic-p &optional display
2263 This function returns @code{t} if @var{display} is a graphic display
2264 capable of displaying several frames and several different fonts at
2265 once. This is true for displays that use a window system such as X, and
2266 false for text-only terminals.
2269 @defun display-mouse-p &optional display
2270 @cindex mouse, availability
2271 This function returns @code{t} if @var{display} has a mouse available,
2275 @defun display-color-p &optional display
2276 @findex x-display-color-p
2277 This function returns @code{t} if the screen is a color screen.
2278 It used to be called @code{x-display-color-p}, and that name
2279 is still supported as an alias.
2282 @defun display-grayscale-p &optional display
2283 This function returns @code{t} if the screen can display shades of gray.
2284 (All color displays can do this.)
2287 @defun display-supports-face-attributes-p attributes &optional display
2288 @anchor{Display Face Attribute Testing}
2289 This function returns non-@code{nil} if all the face attributes in
2290 @var{attributes} are supported (@pxref{Face Attributes}).
2292 The definition of `supported' is somewhat heuristic, but basically
2293 means that a face containing all the attributes in @var{attributes},
2294 when merged with the default face for display, can be represented in a
2299 different in appearance than the default face, and
2302 `close in spirit' to what the attributes specify, if not exact.
2305 Point (2) implies that a @code{:weight black} attribute will be
2306 satisfied by any display that can display bold, as will
2307 @code{:foreground "yellow"} as long as some yellowish color can be
2308 displayed, but @code{:slant italic} will @emph{not} be satisfied by
2309 the tty display code's automatic substitution of a `dim' face for
2313 @defun display-selections-p &optional display
2314 This function returns @code{t} if @var{display} supports selections.
2315 Windowed displays normally support selections, but they may also be
2316 supported in some other cases.
2319 @defun display-images-p &optional display
2320 This function returns @code{t} if @var{display} can display images.
2321 Windowed displays ought in principle to handle images, but some
2322 systems lack the support for that. On a display that does not support
2323 images, Emacs cannot display a tool bar.
2326 @defun display-screens &optional display
2327 This function returns the number of screens associated with the display.
2330 @defun display-pixel-height &optional display
2331 This function returns the height of the screen in pixels.
2332 On a character terminal, it gives the height in characters.
2334 For graphical terminals, note that on ``multi-monitor'' setups this
2335 refers to the pixel width for all physical monitors associated with
2336 @var{display}. @xref{Multiple Terminals}.
2339 @defun display-pixel-width &optional display
2340 This function returns the width of the screen in pixels.
2341 On a character terminal, it gives the width in characters.
2343 For graphical terminals, note that on ``multi-monitor'' setups this
2344 refers to the pixel width for all physical monitors associated with
2345 @var{display}. @xref{Multiple Terminals}.
2348 @defun display-mm-height &optional display
2349 This function returns the height of the screen in millimeters,
2350 or @code{nil} if Emacs cannot get that information.
2353 @defun display-mm-width &optional display
2354 This function returns the width of the screen in millimeters,
2355 or @code{nil} if Emacs cannot get that information.
2358 @defopt display-mm-dimensions-alist
2359 This variable allows the user to specify the dimensions of graphical
2360 displays returned by @code{display-mm-height} and
2361 @code{display-mm-width} in case the system provides incorrect values.
2364 @defun display-backing-store &optional display
2365 This function returns the backing store capability of the display.
2366 Backing store means recording the pixels of windows (and parts of
2367 windows) that are not exposed, so that when exposed they can be
2368 displayed very quickly.
2370 Values can be the symbols @code{always}, @code{when-mapped}, or
2371 @code{not-useful}. The function can also return @code{nil}
2372 when the question is inapplicable to a certain kind of display.
2375 @defun display-save-under &optional display
2376 This function returns non-@code{nil} if the display supports the
2377 SaveUnder feature. That feature is used by pop-up windows
2378 to save the pixels they obscure, so that they can pop down
2382 @defun display-planes &optional display
2383 This function returns the number of planes the display supports.
2384 This is typically the number of bits per pixel.
2385 For a tty display, it is log to base two of the number of colors supported.
2388 @defun display-visual-class &optional display
2389 This function returns the visual class for the screen. The value is one
2390 of the symbols @code{static-gray}, @code{gray-scale},
2391 @code{static-color}, @code{pseudo-color}, @code{true-color}, and
2392 @code{direct-color}.
2395 @defun display-color-cells &optional display
2396 This function returns the number of color cells the screen supports.
2399 These functions obtain additional information specifically
2402 @defun x-server-version &optional display
2403 This function returns the list of version numbers of the X server
2404 running the display. The value is a list of three integers: the major
2405 and minor version numbers of the X protocol, and the
2406 distributor-specific release number of the X server software itself.
2409 @defun x-server-vendor &optional display
2410 This function returns the ``vendor'' that provided the X server
2411 software (as a string). Really this means whoever distributes the X
2414 When the developers of X labelled software distributors as
2415 ``vendors,'' they showed their false assumption that no system could
2416 ever be developed and distributed noncommercially.
2420 @defvar x-no-window-manager
2421 This variable's value is @code{t} if no X window manager is in use.
2427 The functions @code{x-pixel-width} and @code{x-pixel-height} return the
2428 width and height of an X Window frame, measured in pixels.
2433 arch-tag: 94977df6-3dca-4730-b57b-c6329e9282ba