2 @c This is part of the GNU Emacs Lisp Reference Manual.
3 @c Copyright (C) 1990-1995, 1998-1999, 2001-2015 Free Software
5 @c See the file elisp.texi for copying conditions.
10 A @dfn{frame} is a screen object that contains one or more Emacs
11 windows (@pxref{Windows}). It is the kind of object called a
12 ``window'' in the terminology of graphical environments; but we can't
13 call it a ``window'' here, because Emacs uses that word in a different
14 way. In Emacs Lisp, a @dfn{frame object} is a Lisp object that
15 represents a frame on the screen. @xref{Frame Type}.
17 A frame initially contains a single main window and/or a minibuffer
18 window; you can subdivide the main window vertically or horizontally
19 into smaller windows. @xref{Splitting Windows}.
22 A @dfn{terminal} is a display device capable of displaying one or
23 more Emacs frames. In Emacs Lisp, a @dfn{terminal object} is a Lisp
24 object that represents a terminal. @xref{Terminal Type}.
27 @cindex graphical terminal
28 @cindex graphical display
29 There are two classes of terminals: @dfn{text terminals} and
30 @dfn{graphical terminals}. Text terminals are non-graphics-capable
31 displays, including @command{xterm} and other terminal emulators. On
32 a text terminal, each Emacs frame occupies the terminal's entire
33 screen; although you can create additional frames and switch between
34 them, the terminal only shows one frame at a time. Graphical
35 terminals, on the other hand, are managed by graphical display systems
36 such as the X Window System, which allow Emacs to show multiple frames
37 simultaneously on the same display.
39 On GNU and Unix systems, you can create additional frames on any
40 available terminal, within a single Emacs session, regardless of
41 whether Emacs was started on a text or graphical terminal. Emacs can
42 display on both graphical and text terminals simultaneously. This
43 comes in handy, for instance, when you connect to the same session
44 from several remote locations. @xref{Multiple Terminals}.
47 This predicate returns a non-@code{nil} value if @var{object} is a
48 frame, and @code{nil} otherwise. For a frame, the value indicates which
49 kind of display the frame uses:
53 The frame is displayed on a text terminal.
55 The frame is displayed on an X graphical terminal.
57 The frame is displayed on a MS-Windows graphical terminal.
59 The frame is displayed on a GNUstep or Macintosh Cocoa graphical
62 The frame is displayed on an MS-DOS terminal.
66 @defun frame-terminal &optional frame
67 This function returns the terminal object that displays @var{frame}.
68 If @var{frame} is @code{nil} or unspecified, it defaults to the
72 @defun terminal-live-p object
73 This predicate returns a non-@code{nil} value if @var{object} is a
74 terminal that is live (i.e., not deleted), and @code{nil} otherwise.
75 For live terminals, the return value indicates what kind of frames are
76 displayed on that terminal; the list of possible values is the same as
77 for @code{framep} above.
81 * Creating Frames:: Creating additional frames.
82 * Multiple Terminals:: Displaying on several different devices.
83 * Frame Geometry:: Geometric properties of frames.
84 * Frame Parameters:: Controlling frame size, position, font, etc.
85 * Terminal Parameters:: Parameters common for all frames on terminal.
86 * Frame Titles:: Automatic updating of frame titles.
87 * Deleting Frames:: Frames last until explicitly deleted.
88 * Finding All Frames:: How to examine all existing frames.
89 * Minibuffers and Frames:: How a frame finds the minibuffer to use.
90 * Input Focus:: Specifying the selected frame.
91 * Visibility of Frames:: Frames may be visible or invisible, or icons.
92 * Raising and Lowering:: Raising a frame makes it hide other windows;
93 lowering it makes the others hide it.
94 * Frame Configurations:: Saving the state of all frames.
95 * Mouse Tracking:: Getting events that say when the mouse moves.
96 * Mouse Position:: Asking where the mouse is, or moving it.
97 * Pop-Up Menus:: Displaying a menu for the user to select from.
98 * Dialog Boxes:: Displaying a box to ask yes or no.
99 * Pointer Shape:: Specifying the shape of the mouse pointer.
100 * Window System Selections:: Transferring text to and from other X clients.
101 * Drag and Drop:: Internals of Drag-and-Drop implementation.
102 * Color Names:: Getting the definitions of color names.
103 * Text Terminal Colors:: Defining colors for text terminals.
104 * Resources:: Getting resource values from the server.
105 * Display Feature Testing:: Determining the features of a terminal.
108 @node Creating Frames
109 @section Creating Frames
110 @cindex frame creation
112 To create a new frame, call the function @code{make-frame}.
114 @deffn Command make-frame &optional alist
115 This function creates and returns a new frame, displaying the current
118 The @var{alist} argument is an alist that specifies frame parameters
119 for the new frame. @xref{Frame Parameters}. If you specify the
120 @code{terminal} parameter in @var{alist}, the new frame is created on
121 that terminal. Otherwise, if you specify the @code{window-system}
122 frame parameter in @var{alist}, that determines whether the frame
123 should be displayed on a text terminal or a graphical terminal.
124 @xref{Window Systems}. If neither is specified, the new frame is
125 created in the same terminal as the selected frame.
127 Any parameters not mentioned in @var{alist} default to the values in
128 the alist @code{default-frame-alist} (@pxref{Initial Parameters});
129 parameters not specified there default from the X resources or its
130 equivalent on your operating system (@pxref{X Resources,, X Resources,
131 emacs, The GNU Emacs Manual}). After the frame is created, Emacs
132 applies any parameters listed in @code{frame-inherited-parameters}
133 (see below) and not present in the argument, taking the values from
134 the frame that was selected when @code{make-frame} was called.
136 Note that on multi-monitor displays (@pxref{Multiple Terminals}), the
137 window manager might position the frame differently than specified by
138 the positional parameters in @var{alist} (@pxref{Position
139 Parameters}). For example, some window managers have a policy of
140 displaying the frame on the monitor that contains the largest part of
141 the window (a.k.a.@: the @dfn{dominating} monitor).
143 This function itself does not make the new frame the selected frame.
144 @xref{Input Focus}. The previously selected frame remains selected.
145 On graphical terminals, however, the windowing system may select the
146 new frame for its own reasons.
149 @defvar before-make-frame-hook
150 A normal hook run by @code{make-frame} before it creates the frame.
153 @defvar after-make-frame-functions
154 An abnormal hook run by @code{make-frame} after it creates the frame.
155 Each function in @code{after-make-frame-functions} receives one argument, the
159 @defvar frame-inherited-parameters
160 This variable specifies the list of frame parameters that a newly
161 created frame inherits from the currently selected frame. For each
162 parameter (a symbol) that is an element in the list and is not present
163 in the argument to @code{make-frame}, the function sets the value of
164 that parameter in the created frame to its value in the selected
168 @node Multiple Terminals
169 @section Multiple Terminals
170 @cindex multiple terminals
172 @cindex multiple X displays
173 @cindex displays, multiple
175 Emacs represents each terminal as a @dfn{terminal object} data type
176 (@pxref{Terminal Type}). On GNU and Unix systems, Emacs can use
177 multiple terminals simultaneously in each session. On other systems,
178 it can only use a single terminal. Each terminal object has the
179 following attributes:
183 The name of the device used by the terminal (e.g., @samp{:0.0} or
187 The terminal and keyboard coding systems used on the terminal.
188 @xref{Terminal I/O Encoding}.
191 The kind of display associated with the terminal. This is the symbol
192 returned by the function @code{terminal-live-p} (i.e., @code{x},
193 @code{t}, @code{w32}, @code{ns}, or @code{pc}). @xref{Frames}.
196 A list of terminal parameters. @xref{Terminal Parameters}.
199 There is no primitive for creating terminal objects. Emacs creates
200 them as needed, such as when you call @code{make-frame-on-display}
203 @defun terminal-name &optional terminal
204 This function returns the file name of the device used by
205 @var{terminal}. If @var{terminal} is omitted or @code{nil}, it
206 defaults to the selected frame's terminal. @var{terminal} can also be
207 a frame, meaning that frame's terminal.
211 This function returns a list of all live terminal objects.
214 @defun get-device-terminal device
215 This function returns a terminal whose device name is given by
216 @var{device}. If @var{device} is a string, it can be either the file
217 name of a terminal device, or the name of an X display of the form
218 @samp{@var{host}:@var{server}.@var{screen}}. If @var{device} is a
219 frame, this function returns that frame's terminal; @code{nil} means
220 the selected frame. Finally, if @var{device} is a terminal object
221 that represents a live terminal, that terminal is returned. The
222 function signals an error if its argument is none of the above.
225 @defun delete-terminal &optional terminal force
226 This function deletes all frames on @var{terminal} and frees the
227 resources used by it. It runs the abnormal hook
228 @code{delete-terminal-functions}, passing @var{terminal} as the
229 argument to each function.
231 If @var{terminal} is omitted or @code{nil}, it defaults to the
232 selected frame's terminal. @var{terminal} can also be a frame,
233 meaning that frame's terminal.
235 Normally, this function signals an error if you attempt to delete the
236 sole active terminal, but if @var{force} is non-@code{nil}, you are
237 allowed to do so. Emacs automatically calls this function when the
238 last frame on a terminal is deleted (@pxref{Deleting Frames}).
241 @defvar delete-terminal-functions
242 An abnormal hook run by @code{delete-terminal}. Each function
243 receives one argument, the @var{terminal} argument passed to
244 @code{delete-terminal}. Due to technical details, the functions may
245 be called either just before the terminal is deleted, or just
249 @cindex terminal-local variables
250 A few Lisp variables are @dfn{terminal-local}; that is, they have a
251 separate binding for each terminal. The binding in effect at any time
252 is the one for the terminal that the currently selected frame belongs
253 to. These variables include @code{default-minibuffer-frame},
254 @code{defining-kbd-macro}, @code{last-kbd-macro}, and
255 @code{system-key-alist}. They are always terminal-local, and can
256 never be buffer-local (@pxref{Buffer-Local Variables}).
258 On GNU and Unix systems, each X display is a separate graphical
259 terminal. When Emacs is started from within the X window system, it
260 uses the X display specified by the @env{DISPLAY} environment
261 variable, or by the @samp{--display} option (@pxref{Initial Options,,,
262 emacs, The GNU Emacs Manual}). Emacs can connect to other X displays
263 via the command @code{make-frame-on-display}. Each X display has its
264 own selected frame and its own minibuffer windows; however, only one
265 of those frames is @emph{the} selected frame at any given moment
266 (@pxref{Input Focus}). Emacs can even connect to other text
267 terminals, by interacting with the @command{emacsclient} program.
268 @xref{Emacs Server,,, emacs, The GNU Emacs Manual}.
270 @cindex X display names
271 @cindex display name on X
272 A single X server can handle more than one display. Each X display
273 has a three-part name,
274 @samp{@var{hostname}:@var{displaynumber}.@var{screennumber}}. The
275 first part, @var{hostname}, specifies the name of the machine to which
276 the display is physically connected. The second part,
277 @var{displaynumber}, is a zero-based number that identifies one or
278 more monitors connected to that machine that share a common keyboard
279 and pointing device (mouse, tablet, etc.). The third part,
280 @var{screennumber}, identifies a zero-based screen number (a separate
281 monitor) that is part of a single monitor collection on that X server.
282 When you use two or more screens belonging to one server, Emacs knows
283 by the similarity in their names that they share a single keyboard.
285 Systems that don't use the X window system, such as MS-Windows,
286 don't support the notion of X displays, and have only one display on
287 each host. The display name on these systems doesn't follow the above
288 3-part format; for example, the display name on MS-Windows systems is
289 a constant string @samp{w32}, and exists for compatibility, so that
290 you could pass it to functions that expect a display name.
292 @deffn Command make-frame-on-display display &optional parameters
293 This function creates and returns a new frame on @var{display}, taking
294 the other frame parameters from the alist @var{parameters}.
295 @var{display} should be the name of an X display (a string).
297 Before creating the frame, this function ensures that Emacs is set
298 up to display graphics. For instance, if Emacs has not processed X
299 resources (e.g., if it was started on a text terminal), it does so at
300 this time. In all other respects, this function behaves like
301 @code{make-frame} (@pxref{Creating Frames}).
304 @defun x-display-list
305 This function returns a list that indicates which X displays Emacs has
306 a connection to. The elements of the list are strings, and each one
310 @defun x-open-connection display &optional xrm-string must-succeed
311 This function opens a connection to the X display @var{display},
312 without creating a frame on that display. Normally, Emacs Lisp
313 programs need not call this function, as @code{make-frame-on-display}
314 calls it automatically. The only reason for calling it is to check
315 whether communication can be established with a given X display.
317 The optional argument @var{xrm-string}, if not @code{nil}, is a string
318 of resource names and values, in the same format used in the
319 @file{.Xresources} file. @xref{X Resources,, X Resources, emacs, The
320 GNU Emacs Manual}. These values apply to all Emacs frames created on
321 this display, overriding the resource values recorded in the X server.
322 Here's an example of what this string might look like:
325 "*BorderWidth: 3\n*InternalBorder: 2\n"
328 If @var{must-succeed} is non-@code{nil}, failure to open the connection
329 terminates Emacs. Otherwise, it is an ordinary Lisp error.
332 @defun x-close-connection display
333 This function closes the connection to display @var{display}. Before
334 you can do this, you must first delete all the frames that were open
335 on that display (@pxref{Deleting Frames}).
338 @cindex multi-monitor
339 On some multi-monitor setups, a single X display outputs to more
340 than one physical monitor. You can use the functions
341 @code{display-monitor-attributes-list} and @code{frame-monitor-attributes}
342 to obtain information about such setups.
344 @defun display-monitor-attributes-list &optional display
345 This function returns a list of physical monitor attributes on
346 @var{display}, which can be a display name (a string), a terminal, or
347 a frame; if omitted or @code{nil}, it defaults to the selected frame's
348 display. Each element of the list is an association list,
349 representing the attributes of a physical monitor. The first element
350 corresponds to the primary monitor. The attribute keys and values
355 Position of the top-left corner of the monitor's screen and its size,
356 in pixels, as @samp{(@var{x} @var{y} @var{width} @var{height})}. Note
357 that, if the monitor is not the primary monitor, some of the
358 coordinates might be negative.
361 Position of the top-left corner and size of the work area (usable
362 space) in pixels as @samp{(@var{x} @var{y} @var{width} @var{height})}.
363 This may be different from @samp{geometry} in that space occupied by
364 various window manager features (docks, taskbars, etc.)@: may be
365 excluded from the work area. Whether or not such features actually
366 subtract from the work area depends on the platform and environment.
367 Again, if the monitor is not the primary monitor, some of the
368 coordinates might be negative.
371 Width and height in millimeters as @samp{(@var{width} @var{height})}
374 List of frames that this physical monitor dominates (see below).
377 Name of the physical monitor as @var{string}.
380 Source of the multi-monitor information as @var{string};
381 e.g., @samp{XRandr} or @samp{Xinerama}.
384 @var{x}, @var{y}, @var{width}, and @var{height} are integers.
385 @samp{name} and @samp{source} may be absent.
387 A frame is @dfn{dominated} by a physical monitor when either the
388 largest area of the frame resides in that monitor, or (if the frame
389 does not intersect any physical monitors) that monitor is the closest
390 to the frame. Every (non-tooltip) frame (whether visible or not) in a
391 graphical display is dominated by exactly one physical monitor at a
392 time, though the frame can span multiple (or no) physical monitors.
394 Here's an example of the data produced by this function on a 2-monitor
398 (display-monitor-attributes-list)
400 (((geometry 0 0 1920 1080) ;; @r{Left-hand, primary monitor}
401 (workarea 0 0 1920 1050) ;; @r{A taskbar occupies some of the height}
404 (frames #<frame emacs@@host *Messages* 0x11578c0>
405 #<frame emacs@@host *scratch* 0x114b838>))
406 ((geometry 1920 0 1680 1050) ;; @r{Right-hand monitor}
407 (workarea 1920 0 1680 1050) ;; @r{Whole screen can be used}
415 @defun frame-monitor-attributes &optional frame
416 This function returns the attributes of the physical monitor
417 dominating (see above) @var{frame}, which defaults to the selected frame.
422 @section Frame Geometry
423 @cindex frame geometry
424 @cindex frame position
425 @cindex position of frame
427 @cindex size of frame
429 The geometry of a frame depends on the toolkit that was used to build
430 this instance of Emacs and the terminal that displays the frame. This
431 chapter describes these dependencies and some of the functions to deal
432 with them. Note that the @var{frame} argument of all of these functions
433 has to specify a live frame (@pxref{Deleting Frames}). If omitted or
434 @code{nil}, it specifies the selected frame (@pxref{Input Focus}).
437 * Frame Layout:: Basic layout of frames.
438 * Frame Font:: The default font of a frame and how to set it.
439 * Size and Position:: Changing the size and position of a frame.
440 * Implied Frame Resizing:: Implied resizing of frames and how to prevent it.
445 @subsection Frame Layout
447 @cindex layout of frame
449 The drawing below sketches the layout of a frame on a graphical
454 <------------ Outer Frame Width ----------->
455 ___________________________________________
456 ^(0) ___________ External Border __________ |
457 | | |_____________ Title Bar ______________| |
458 | | (1)_____________ Menu Bar ______________| | ^
459 | | (2)_____________ Tool Bar ______________| | ^
460 | | (3) _________ Internal Border ________ | | ^
463 Outer | | | Inner | | | Native
464 Frame | | | Frame | | | Frame
465 Height | | | Height | | | Height
467 | | | |<--+--- Inner Frame Width ------->| | | |
469 | | | |___v______________________________| | | |
470 | | |___________ Internal Border __________| | v
471 v |______________ External Border _____________|
472 <-------- Native Frame Width -------->
477 In practice not all of the areas shown in the drawing will or may be
478 present. The meaning of these areas is:
486 The @dfn{outer frame} is a rectangle comprising all areas shown in the
487 drawing. The edges of that rectangle are called the @dfn{outer edges}
488 of the frame. The @dfn{outer width} and @dfn{outer height} of the frame
489 specify the size of that rectangle.
491 @cindex outer position
492 The upper left corner of the outer frame (indicated by @samp{(0)} in the
493 drawing above) is the @dfn{outer position} or the frame. It is
494 specified by and settable via the @code{left} and @code{top} frame
495 parameters (@pxref{Position Parameters}) as well as the functions
496 @code{frame-position} and @code{set-frame-position} (@pxref{Size and
499 @item External Border
500 @cindex external border
501 The @dfn{external border} is part of the decorations supplied by the
502 window manager. It's typically used for resizing the frame with the
503 mouse. The external border is normally not shown on fullboth and
504 maximized frames (@pxref{Size Parameters}) and doesn't exist for text
507 The external border should not be confused with the @dfn{outer
508 border} specified by the @code{border-width} frame parameter
509 (@pxref{Layout Parameters}). Since the outer border is usually ignored
510 on most platforms it is not covered here.
514 The @dfn{title bar} is also part of the window manager's decorations and
515 typically displays the title of the frame (@pxref{Frame Titles}) as well
516 as buttons for minimizing, maximizing and deleting the frame. The title
517 bar is usually not displayed on fullboth (@pxref{Size Parameters})
518 or tooltip frames. Title bars don't exist for text terminal frames.
521 @cindex internal menu bar
522 @cindex external menu bar
523 The menu bar (@pxref{Menu Bar}) can be either internal (drawn by Emacs
524 itself) or external (drawn by a toolkit). Most builds (GTK+, Lucid,
525 Motif and Windows) rely on an external menu bar. NS also uses an
526 external menu bar which, however, is not part of the outer frame.
527 Non-toolkit builds can provide an internal menu bar. On text terminal
528 frames, the menu bar is part of the frame's root window (@pxref{Windows
532 @cindex internal tool bar
533 @cindex external tool bar
534 Like the menu bar, the tool bar (@pxref{Tool Bar}) can be either
535 internal (drawn by Emacs itself) or external (drawn by a toolkit). The
536 GTK+ and NS builds have the tool bar drawn by the toolkit. The
537 remaining builds use internal tool bars. With GTK+ the tool bar can be
538 located on either side of the frame, immediately outside the internal
545 @cindex native height
547 The @dfn{native frame} is a rectangle located entirely within the outer
548 frame. It excludes the areas occupied by the external border, the title
549 bar and any external menu or external tool bar. The area enclosed by
550 the native frame is sometimes also referred to as the @dfn{display area}
551 of the frame. The edges of the native frame are called the @dfn{native
552 edges} of the frame. The @dfn{native width} and @dfn{native height} of
553 the frame specify the size of the rectangle.
555 @cindex native position
556 The top left corner of the native frame specifies the @dfn{native
557 position} of the frame. (1)--(3) in the drawing above indicate that
558 position for the various builds:
561 @item (1) non-toolkit and terminal frames
563 @item (2) Lucid, Motif and Windows frames
565 @item (3) GTK+ and NS frames
568 Accordingly, the native height of a frame includes the height of the
569 tool bar but not that of the menu bar (Lucid, Motif, Windows) or those
570 of the menu bar and the tool bar (non-toolkit and text terminal frames).
572 The native position of a frame is the reference position of functions
573 that set or return the current position of the mouse (@pxref{Mouse
574 Position}) and for functions dealing with the position of windows like
575 @code{window-edges}, @code{window-at} or @code{coordinates-in-window-p}
576 (@pxref{Coordinates and Windows}).
578 @item Internal Border
579 The internal border (@pxref{Layout Parameters}) is a border drawn by
580 Emacs around the inner frame (see below).
587 The @dfn{inner frame} is the rectangle reserved for the frame's windows.
588 It's enclosed by the internal border which, however, is not part of the
589 inner frame. Its edges are called the @dfn{inner edges} of the frame.
590 The @dfn{inner width} and @dfn{inner height} specify the size of the
593 @cindex minibuffer-less frame
594 @cindex minibuffer-only frame
595 As a rule, the inner frame is subdivided into the frame's root window
596 (@pxref{Windows and Frames}) and the frame's minibuffer window
597 (@pxref{Minibuffer Windows}). There are two notable exceptions to this
598 rule: A @dfn{minibuffer-less frame} contains a root window only and does
599 not contain a minibuffer window. A @dfn{minibuffer-only frame} contains
600 only a minibuffer window which also serves as that frame's root window.
601 See @ref{Initial Parameters} for how to create such frame
606 The @dfn{text area} of a frame is a somewhat fictitious area located
607 entirely within the native frame. It can be obtained by removing from
608 the native frame any internal borders, one vertical and one horizontal
609 scroll bar, and one left and one right fringe as specified for this
610 frame, see @ref{Layout Parameters}.
613 @cindex absolute position
614 The @dfn{absolute position} of a frame or its edges is usually given in
615 terms of pixels counted from an origin at position (0, 0) of the frame's
616 display. Note that with multiple monitors the origin does not
617 necessarily coincide with the top left corner of the entire usable
618 display area. Hence the absolute outer position of a frame or the
619 absolute positions of the edges of the outer, native or inner frame can
620 be negative in such an environment even when that frame is completely
623 For a frame on a graphical terminal the following function returns the
624 sizes of the areas described above:
626 @defun frame-geometry &optional frame
627 This function returns geometric attributes of @var{frame}. The return
628 value is an association list of the attributes listed below. All
629 coordinate, height and width values are integers counting pixels.
633 A cons of the absolute X- and Y-coordinates of the outer position of
634 @var{frame}, relative to the origin at position (0, 0) of @var{frame}'s
638 A cons of the outer width and height of @var{frame}.
640 @item external-border-size
641 A cons of the horizontal and vertical width of @var{frame}'s external
642 borders as supplied by the window manager. If the window manager
643 doesn't supply these values, Emacs will try to guess them from the
644 coordinates of the outer and inner frame.
647 A cons of the width and height of the title bar of @var{frame} as
648 supplied by the window manager or operating system. If both of them are
649 zero, the frame has no title bar. If only the width is zero, Emacs was
650 not able to retrieve the width information.
652 @item menu-bar-external
653 If non-@code{nil}, this means the menu bar is external (not part of the
654 native frame of @var{frame}).
657 A cons of the width and height of the menu bar of @var{frame}.
659 @item tool-bar-external
660 If non-@code{nil}, this means the tool bar is external (not part of the
661 native frame of @var{frame}).
663 @item tool-bar-position
664 This tells on which side the tool bar on @var{frame} is and can be one
665 of @code{left}, @code{top}, @code{right} or @code{bottom}. The only
666 toolkit that currently supports a value other than @code{top} is GTK+.
669 A cons of the width and height of the tool bar of @var{frame}.
671 @item internal-border-width
672 The width of the internal border of @var{frame}.
676 The following function can be used to retrieve the edges of the outer,
677 native and inner frame.
679 @defun frame-edges &optional frame type
680 This function returns the edges of the outer, native or inner frame of
681 @var{frame}. @var{frame} must be a live frame and defaults to the
682 selected one. The list returned has the form (@var{left} @var{top}
683 @var{right} @var{bottom}) where all values are in pixels relative to the
684 position (0, 0) of @var{frame}'s display. For terminal frames
685 @var{left} and @var{top} are both zero.
687 Optional argument @var{type} specifies the type of the edges to return:
688 @var{type} @code{outer-edges} means to return the outer edges of
689 @var{frame}, @code{native-edges} (or @code{nil}) means to return its
690 native edges and @code{inner-edges} means to return its inner edges.
692 Notice that the pixels at the positions @var{bottom} and @var{right}
693 lie immediately outside the corresponding frame. This means that if you
694 have, for example, two side-by-side frames positioned such that the
695 right outer edge of the frame on the left equals the left outer edge of
696 the frame on the right, the pixels representing that edge are part
697 of the frame on the right.
702 @subsection Frame Font
704 @cindex default character size
705 @cindex default character width
706 @cindex default width of character
707 @cindex default character height
708 @cindex default height of character
709 Each frame has a @dfn{default font} which specifies the default
710 character size for that frame. This size is meant when retrieving or
711 changing the size of a frame in terms of columns or lines
712 (@pxref{Size Parameters}). It is also used when resizing (@pxref{Window
713 Sizes}) or splitting (@pxref{Splitting Windows}) windows.
717 The term @dfn{line height} is sometimes used instead of ``default
718 character height''. Similarly, the term @dfn{column width} is used as
719 shorthand for ``default character width''.
721 @defun frame-char-height &optional frame
722 @defunx frame-char-width &optional frame
723 These functions return the default height and width of a character in
724 @var{frame}, measured in pixels. Together, these values establish the
725 size of the default font on @var{frame}. The values depend on the
726 choice of font for @var{frame}, see @ref{Font and Color Parameters}.
729 The default font can be also set directly with the following function:
731 @deffn Command set-frame-font font &optional keep-size frames
732 This sets the default font to @var{font}. When called interactively, it
733 prompts for the name of a font, and uses that font on the selected
734 frame. When called from Lisp, @var{font} should be a font name (a
735 string), a font object, font entity, or a font spec.
737 If the optional argument @var{keep-size} is @code{nil}, this keeps the
738 number of frame lines and columns fixed. (If non-@code{nil}, the option
739 @code{frame-inhibit-implied-resize} described in the next section will
740 override this.) If @var{keep-size} is non-@code{nil} (or with a prefix
741 argument), it tries to keep the size of the display area of the current
742 frame fixed by adjusting the number of lines and columns.
744 If the optional argument @var{frames} is @code{nil}, this applies the
745 font to the selected frame only. If @var{frames} is non-@code{nil}, it
746 should be a list of frames to act upon, or @code{t} meaning all existing
747 and all future graphical frames.
751 @node Size and Position
752 @subsection Size and Position
754 @cindex frame position
755 @cindex position of frame
757 You can read or change the position of a frame using the frame
758 parameters @code{left} and @code{top} (@pxref{Position Parameters}) and
759 its size using the @code{height} and @code{width} parameters
760 (@pxref{Size Parameters}). Here are some special features for working
761 with sizes and positions. For all of these functions the argument
762 @var{frame} must denote a live frame and defaults to the selected frame.
764 @defun frame-position &optional Lisp_Object &optional frame
765 This function returns the outer position (@pxref{Frame Layout}) of
766 @var{frame} in pixels. The value is a cons giving the coordinates of
767 the top left corner of the outer frame of @var{frame} relative to an
768 origin at the position (0, 0) of the frame's display. On a text
769 terminal frame both values are zero.
772 @defun set-frame-position frame X Y
773 This function sets the outer frame position of @var{frame} to @var{X}
774 and @var{Y}. The latter arguments specify pixels and normally count
775 from an origin at the position (0, 0) of @var{frame}'s display.
777 A negative parameter value positions the right edge of the outer frame
778 by @var{-x} pixels left from the right edge of the screen or the bottom
779 edge by @var{-y} pixels up from the bottom edge of the screen.
781 This function has no effect on text terminal frames.
784 @defun frame-pixel-height &optional frame
785 @defunx frame-pixel-width &optional frame
786 These functions return the inner height and width (the height and
787 width of the display area, see @ref{Frame Layout}) of @var{frame} in
788 pixels. For a text terminal, the results are in characters rather than
792 @defun frame-text-height &optional frame
793 @defunx frame-text-width &optional frame
794 These functions return the height and width of the text area of
795 @var{frame} (@pxref{Frame Layout}), measured in pixels. For a text
796 terminal, the results are in characters rather than pixels.
798 The value returned by @code{frame-text-height} differs from that
799 returned by @code{frame-pixel-height} by not including the heights of
800 any internal tool bar or menu bar, the height of one horizontal scroll
801 bar and the widths of the internal border.
803 The value returned by @code{frame-text-width} differs from that returned
804 by @code{frame-pixel-width} by not including the width of one vertical
805 scroll bar, the widths of one left and one right fringe and the widths
806 of the internal border.
809 @defun frame-height &optional frame
810 @defunx frame-width &optional frame
811 These functions return the height and width of the text area of
812 @var{frame}, measured in units of the default font height and width of
813 @var{frame} (@pxref{Frame Font}). These functions are plain shorthands
814 for writing @code{(frame-parameter frame 'height)} and
815 @code{(frame-parameter frame 'width)}.
817 If the text area of @var{frame} measured in pixels is not a multiple of
818 its default font size, the values returned by these functions are
819 rounded down to the number of characters of the default font that fully
820 fit into the text area.
823 @defopt frame-resize-pixelwise
824 If this option is @code{nil}, a frame's size is usually rounded to a
825 multiple of the current values of that frame's @code{frame-char-height}
826 and @code{frame-char-width} whenever the frame is resized. If this is
827 non-@code{nil}, no rounding occurs, hence frame sizes can
828 increase/decrease by one pixel.
830 Setting this variable usually causes the next resize operation to pass
831 the corresponding size hints to the window manager. This means that
832 this variable should be set only in a user's initial file; applications
833 should never bind it temporarily.
835 The precise meaning of a value of @code{nil} for this option depends on
836 the toolkit used. Dragging the external border with the mouse is done
837 character-wise provided the window manager is willing to process the
838 corresponding size hints. Calling @code{set-frame-size} (see below)
839 with arguments that do not specify the frame size as an integer multiple
840 of its character size, however, may: be ignored, cause a rounding
841 (GTK+), or be accepted (Lucid, Motif, MS-Windows).
843 With some window managers you may have to set this to non-@code{nil} in
844 order to make a frame appear truly maximized or fullscreen.
847 @defun set-frame-size frame width height pixelwise
848 This function sets the size of the text area of @var{frame}, measured in
849 terms of the canonical height and width of a character on @var{frame}
850 (@pxref{Frame Font}).
852 The optional argument @var{pixelwise} non-@code{nil} means to measure
853 the new width and height in units of pixels instead. Note that if
854 @code{frame-resize-pixelwise} is @code{nil}, some toolkits may refuse to
855 fully honor the request if it does not increase/decrease the frame size
856 to a multiple of its character size.
859 @defun set-frame-height frame height &optional pretend pixelwise
860 This function resizes the text area of @var{frame} to a height of
861 @var{height} lines. The sizes of existing windows in @var{frame} are
862 altered proportionally to fit.
864 If @var{pretend} is non-@code{nil}, then Emacs displays @var{height}
865 lines of output in @var{frame}, but does not change its value for the
866 actual height of the frame. This is only useful on text terminals.
867 Using a smaller height than the terminal actually implements may be
868 useful to reproduce behavior observed on a smaller screen, or if the
869 terminal malfunctions when using its whole screen. Setting the frame
870 height directly does not always work, because knowing the correct
871 actual size may be necessary for correct cursor positioning on
874 The optional fourth argument @var{pixelwise} non-@code{nil} means that
875 @var{frame} should be @var{height} pixels high. Note that if
876 @code{frame-resize-pixelwise} is @code{nil}, some toolkits may refuse to
877 fully honor the request if it does not increase/decrease the frame
878 height to a multiple of its character height.
881 @defun set-frame-width frame width &optional pretend pixelwise
882 This function sets the width of the text area of @var{frame}, measured
883 in characters. The argument @var{pretend} has the same meaning as in
884 @code{set-frame-height}.
886 The optional fourth argument @var{pixelwise} non-@code{nil} means that
887 @var{frame} should be @var{width} pixels wide. Note that if
888 @code{frame-resize-pixelwise} is @code{nil}, some toolkits may refuse to
889 fully honor the request if it does not increase/decrease the frame width
890 to a multiple of its character width.
893 None of these three functions will make a frame smaller than needed to
894 display all of its windows together with their scroll bars, fringes,
895 margins, dividers, mode and header lines. This contrasts with requests
896 by the window manager triggered, for example, by dragging the external
897 border of a frame with the mouse. Such requests are always honored by
898 clipping, if necessary, portions that cannot be displayed at the right,
899 bottom corner of the frame.
902 @node Implied Frame Resizing
903 @subsection Implied Frame Resizing
904 @cindex implied frame resizing
905 @cindex implied resizing of frame
907 By default, Emacs tries to keep the number of lines and columns of a
908 frame's text area unaltered when, for example, adding or removing the
909 menu bar, changing the default font or setting the width of the frame's
910 scroll bars. This means, however, that in such case Emacs must ask the
911 window manager to resize the outer frame in order to accommodate the
912 size change. Note that wrapping a menu or tool bar usually does not
913 resize the frame's outer size, hence this will alter the number of
916 Occasionally, such @dfn{implied frame resizing} may be unwanted, for
917 example, when the frame is maximized or made fullscreen (where it's
918 turned off by default). In other cases you can disable implied resizing
919 with the following option:
921 @defopt frame-inhibit-implied-resize
922 If this option is @code{nil}, changing font, menu bar, tool bar,
923 internal borders, fringes or scroll bars of a specific frame may
924 implicitly resize the frame's display area in order to preserve the
925 number of columns or lines the frame displays. If this option is
926 non-@code{nil}, no implied resizing is done.
928 The value of this option can be also be a list of frame parameters. In
929 that case, implied resizing is inhibited when changing a parameter that
930 appears in this list. The frame parameters currently handled by this
931 option are: @code{font}, @code{font-backend},
932 @code{internal-border-width}, @code{menu-bar-lines} and
933 @code{tool-bar-lines}.
935 Changing any of the @code{scroll-bar-width}, @code{scroll-bar-height},
936 @code{vertical-scroll-bars}, @code{horizontal-scroll-bars},
937 @code{left-fringe} and @code{right-fringe} frame parameters is handled
938 as if the frame contained just one live window. This means, for
939 example, that removing vertical scroll bars on a frame containing
940 several side by side windows will shrink the outer frame width by the
941 width of one scroll bar provided this option is @code{nil} and keep it
942 unchanged if this option is either @code{t} or a list containing
943 @code{vertical-scroll-bars}.
945 The default value is @code{'(tool-bar-lines)} for Lucid, Motif and
946 Windows (which means that adding/removing a tool bar there does not
947 change the outer frame height), @code{nil} on all other window systems
948 including GTK+ (which means that changing any of the parameters listed
949 above may change the size of the outer frame), and @code{t} otherwise
950 (which means the outer frame size never changes implicitly when there's
951 no window system support).
953 Note that when a frame is not large enough to accommodate a change of
954 any of the parameters listed above, Emacs may try to enlarge the frame
955 even if this option is non-@code{nil}.
959 @node Frame Parameters
960 @section Frame Parameters
961 @cindex frame parameters
963 A frame has many parameters that control its appearance and behavior.
964 Just what parameters a frame has depends on what display mechanism it
967 Frame parameters exist mostly for the sake of graphical displays.
968 Most frame parameters have no effect when applied to a frame on a text
969 terminal; only the @code{height}, @code{width}, @code{name},
970 @code{title}, @code{menu-bar-lines}, @code{buffer-list} and
971 @code{buffer-predicate} parameters do something special. If the
972 terminal supports colors, the parameters @code{foreground-color},
973 @code{background-color}, @code{background-mode} and
974 @code{display-type} are also meaningful. If the terminal supports
975 frame transparency, the parameter @code{alpha} is also meaningful.
978 * Parameter Access:: How to change a frame's parameters.
979 * Initial Parameters:: Specifying frame parameters when you make a frame.
980 * Window Frame Parameters:: List of frame parameters for window systems.
981 * Geometry:: Parsing geometry specifications.
984 @node Parameter Access
985 @subsection Access to Frame Parameters
987 These functions let you read and change the parameter values of a
990 @defun frame-parameter frame parameter
991 This function returns the value of the parameter @var{parameter} (a
992 symbol) of @var{frame}. If @var{frame} is @code{nil}, it returns the
993 selected frame's parameter. If @var{frame} has no setting for
994 @var{parameter}, this function returns @code{nil}.
997 @defun frame-parameters &optional frame
998 The function @code{frame-parameters} returns an alist listing all the
999 parameters of @var{frame} and their values. If @var{frame} is
1000 @code{nil} or omitted, this returns the selected frame's parameters
1003 @defun modify-frame-parameters frame alist
1004 This function alters the parameters of frame @var{frame} based on the
1005 elements of @var{alist}. Each element of @var{alist} has the form
1006 @code{(@var{parm} . @var{value})}, where @var{parm} is a symbol naming a
1007 parameter. If you don't mention a parameter in @var{alist}, its value
1008 doesn't change. If @var{frame} is @code{nil}, it defaults to the selected
1012 @defun set-frame-parameter frame parm value
1013 This function sets the frame parameter @var{parm} to the specified
1014 @var{value}. If @var{frame} is @code{nil}, it defaults to the
1018 @defun modify-all-frames-parameters alist
1019 This function alters the frame parameters of all existing frames
1020 according to @var{alist}, then modifies @code{default-frame-alist}
1021 (and, if necessary, @code{initial-frame-alist}) to apply the same
1022 parameter values to frames that will be created henceforth.
1025 @node Initial Parameters
1026 @subsection Initial Frame Parameters
1027 @cindex parameters of initial frame
1029 You can specify the parameters for the initial startup frame by
1030 setting @code{initial-frame-alist} in your init file (@pxref{Init
1033 @defopt initial-frame-alist
1034 This variable's value is an alist of parameter values used when
1035 creating the initial frame. You can set this variable to specify the
1036 appearance of the initial frame without altering subsequent frames.
1037 Each element has the form:
1040 (@var{parameter} . @var{value})
1043 Emacs creates the initial frame before it reads your init
1044 file. After reading that file, Emacs checks @code{initial-frame-alist},
1045 and applies the parameter settings in the altered value to the already
1046 created initial frame.
1048 If these settings affect the frame geometry and appearance, you'll see
1049 the frame appear with the wrong ones and then change to the specified
1050 ones. If that bothers you, you can specify the same geometry and
1051 appearance with X resources; those do take effect before the frame is
1052 created. @xref{X Resources,, X Resources, emacs, The GNU Emacs Manual}.
1054 X resource settings typically apply to all frames. If you want to
1055 specify some X resources solely for the sake of the initial frame, and
1056 you don't want them to apply to subsequent frames, here's how to achieve
1057 this. Specify parameters in @code{default-frame-alist} to override the
1058 X resources for subsequent frames; then, to prevent these from affecting
1059 the initial frame, specify the same parameters in
1060 @code{initial-frame-alist} with values that match the X resources.
1063 @cindex minibuffer-only frame
1064 If these parameters include @code{(minibuffer . nil)}, that indicates
1065 that the initial frame should have no minibuffer. In this case, Emacs
1066 creates a separate @dfn{minibuffer-only frame} as well.
1068 @defopt minibuffer-frame-alist
1069 This variable's value is an alist of parameter values used when
1070 creating an initial minibuffer-only frame (i.e., the minibuffer-only
1071 frame that Emacs creates if @code{initial-frame-alist} specifies a
1072 frame with no minibuffer).
1075 @defopt default-frame-alist
1076 This is an alist specifying default values of frame parameters for all
1077 Emacs frames---the first frame, and subsequent frames. When using the X
1078 Window System, you can get the same results by means of X resources
1081 Setting this variable does not affect existing frames. Furthermore,
1082 functions that display a buffer in a separate frame may override the
1083 default parameters by supplying their own parameters.
1086 If you invoke Emacs with command-line options that specify frame
1087 appearance, those options take effect by adding elements to either
1088 @code{initial-frame-alist} or @code{default-frame-alist}. Options
1089 which affect just the initial frame, such as @samp{--geometry} and
1090 @samp{--maximized}, add to @code{initial-frame-alist}; the others add
1091 to @code{default-frame-alist}. @pxref{Emacs Invocation,, Command Line
1092 Arguments for Emacs Invocation, emacs, The GNU Emacs Manual}.
1094 @node Window Frame Parameters
1095 @subsection Window Frame Parameters
1096 @cindex frame parameters for windowed displays
1098 Just what parameters a frame has depends on what display mechanism
1099 it uses. This section describes the parameters that have special
1100 meanings on some or all kinds of terminals. Of these, @code{name},
1101 @code{title}, @code{height}, @code{width}, @code{buffer-list} and
1102 @code{buffer-predicate} provide meaningful information in terminal
1103 frames, and @code{tty-color-mode} is meaningful only for frames on
1107 * Basic Parameters:: Parameters that are fundamental.
1108 * Position Parameters:: The position of the frame on the screen.
1109 * Size Parameters:: Frame's size.
1110 * Layout Parameters:: Size of parts of the frame, and
1111 enabling or disabling some parts.
1112 * Buffer Parameters:: Which buffers have been or should be shown.
1113 * Management Parameters:: Communicating with the window manager.
1114 * Cursor Parameters:: Controlling the cursor appearance.
1115 * Font and Color Parameters:: Fonts and colors for the frame text.
1118 @node Basic Parameters
1119 @subsubsection Basic Parameters
1121 These frame parameters give the most basic information about the
1122 frame. @code{title} and @code{name} are meaningful on all terminals.
1125 @vindex display, a frame parameter
1127 The display on which to open this frame. It should be a string of the
1128 form @samp{@var{host}:@var{dpy}.@var{screen}}, just like the
1129 @env{DISPLAY} environment variable. @xref{Multiple Terminals}, for
1130 more details about display names.
1132 @vindex display-type, a frame parameter
1134 This parameter describes the range of possible colors that can be used
1135 in this frame. Its value is @code{color}, @code{grayscale} or
1138 @vindex title, a frame parameter
1140 If a frame has a non-@code{nil} title, it appears in the window
1141 system's title bar at the top of the frame, and also in the mode line
1142 of windows in that frame if @code{mode-line-frame-identification} uses
1143 @samp{%F} (@pxref{%-Constructs}). This is normally the case when
1144 Emacs is not using a window system, and can only display one frame at
1145 a time. @xref{Frame Titles}.
1147 @vindex name, a frame parameter
1149 The name of the frame. The frame name serves as a default for the frame
1150 title, if the @code{title} parameter is unspecified or @code{nil}. If
1151 you don't specify a name, Emacs sets the frame name automatically
1152 (@pxref{Frame Titles}).
1154 If you specify the frame name explicitly when you create the frame, the
1155 name is also used (instead of the name of the Emacs executable) when
1156 looking up X resources for the frame.
1159 If the frame name was specified explicitly when the frame was created,
1160 this parameter will be that name. If the frame wasn't explicitly
1161 named, this parameter will be @code{nil}.
1164 @node Position Parameters
1165 @subsubsection Position Parameters
1166 @cindex window position on display
1167 @cindex frame position
1169 Position parameters' values are normally measured in pixels, but on
1170 text terminals they count characters or lines instead.
1173 @vindex left, a frame parameter
1175 The position, in pixels, of the left (or right) edge of the frame with
1176 respect to the left (or right) edge of the screen. The value may be:
1180 A positive integer relates the left edge of the frame to the left edge
1181 of the screen. A negative integer relates the right frame edge to the
1184 @item @code{(+ @var{pos})}
1185 This specifies the position of the left frame edge relative to the left
1186 screen edge. The integer @var{pos} may be positive or negative; a
1187 negative value specifies a position outside the screen or on a monitor
1188 other than the primary one (for multi-monitor displays).
1190 @item @code{(- @var{pos})}
1191 This specifies the position of the right frame edge relative to the right
1192 screen edge. The integer @var{pos} may be positive or negative; a
1193 negative value specifies a position outside the screen or on a monitor
1194 other than the primary one (for multi-monitor displays).
1197 Some window managers ignore program-specified positions. If you want to
1198 be sure the position you specify is not ignored, specify a
1199 non-@code{nil} value for the @code{user-position} parameter as well.
1201 If the window manager refuses to align a frame at the left or top screen
1202 edge, combining position notation and @code{user-position} as in
1205 (modify-frame-parameters
1206 nil '((user-position . t) (left . (+ -4))))
1209 may help to override that.
1211 @vindex top, a frame parameter
1213 The screen position of the top (or bottom) edge, in pixels, with respect
1214 to the top (or bottom) edge of the screen. It works just like
1215 @code{left}, except vertically instead of horizontally.
1217 @vindex icon-left, a frame parameter
1219 The screen position of the left edge of the frame's icon, in pixels,
1220 counting from the left edge of the screen. This takes effect when the
1221 frame is iconified, if the window manager supports this feature. If
1222 you specify a value for this parameter, then you must also specify a
1223 value for @code{icon-top} and vice versa.
1225 @vindex icon-top, a frame parameter
1227 The screen position of the top edge of the frame's icon, in pixels,
1228 counting from the top edge of the screen. This takes effect when the
1229 frame is iconified, if the window manager supports this feature.
1231 @vindex user-position, a frame parameter
1233 When you create a frame and specify its screen position with the
1234 @code{left} and @code{top} parameters, use this parameter to say whether
1235 the specified position was user-specified (explicitly requested in some
1236 way by a human user) or merely program-specified (chosen by a program).
1237 A non-@code{nil} value says the position was user-specified.
1239 @cindex window positions and window managers
1240 Window managers generally heed user-specified positions, and some heed
1241 program-specified positions too. But many ignore program-specified
1242 positions, placing the window in a default fashion or letting the user
1243 place it with the mouse. Some window managers, including @code{twm},
1244 let the user specify whether to obey program-specified positions or
1247 When you call @code{make-frame}, you should specify a non-@code{nil}
1248 value for this parameter if the values of the @code{left} and @code{top}
1249 parameters represent the user's stated preference; otherwise, use
1254 @node Size Parameters
1255 @subsubsection Size Parameters
1256 @cindex window size on display
1258 Frame parameters specify frame sizes in character units. On
1259 graphical displays, the @code{default} face determines the actual
1260 pixel sizes of these character units (@pxref{Face Attributes}).
1263 @vindex height, a frame parameter
1265 The height of the frame's text area (@pxref{Frame Geometry}), in
1268 @vindex width, a frame parameter
1270 The width of the frame's text area (@pxref{Frame Geometry}), in
1273 @vindex user-size, a frame parameter
1275 This does for the size parameters @code{height} and @code{width} what
1276 the @code{user-position} parameter (@pxref{Position Parameters,
1277 user-position}) does for the position parameters @code{top} and
1280 @cindex fullboth frames
1281 @cindex fullheight frames
1282 @cindex fullwidth frames
1283 @cindex maximized frames
1284 @vindex fullscreen, a frame parameter
1286 This parameter specifies whether to maximize the frame’s width, height
1287 or both. Its value can be @code{fullwidth}, @code{fullheight},
1288 @code{fullboth}, or @code{maximized}. A @dfn{fullwidth} frame is as
1289 wide as possible, a @dfn{fulleight} frame is as tall as possible, and
1290 a @dfn{fullboth} frame is both as wide and as tall as possible. A
1291 @dfn{maximized} frame is like a fullboth frame, except that it usually
1292 keeps its title bar and the buttons for resizing
1293 and closing the frame. Also, maximized frames typically avoid hiding
1294 any task bar or panels displayed on the desktop. A fullboth frame,
1295 on the other hand, usually omits the title bar and occupies the entire
1296 available screen space.
1298 Fullheight and fullwidth frames are more similar to maximized
1299 frames in this regard. However, these typically display an external
1300 border which might be absent with maximized frames. Hence the heights
1301 of maximized and fullheight frames and the widths of maximized and
1302 fullwidth frames often differ by a few pixels.
1304 With some window managers you may have to customize the variable
1305 @code{frame-resize-pixelwise} (@pxref{Size and Position}) in order to
1306 make a frame truly appear maximized or fullscreen. Moreover,
1307 some window managers might not support smooth transition between the
1308 various fullscreen or maximization states. Customizing the variable
1309 @code{x-frame-normalize-before-maximize} can help to overcome that.
1311 @vindex fullscreen-restore, a frame parameter
1312 @item fullscreen-restore
1313 This parameter specifies the desired fullscreen state of the frame
1314 after invoking the @code{toggle-frame-fullscreen} command (@pxref{Frame
1315 Commands,,, emacs, The GNU Emacs Manual}) in the fullboth state.
1316 Normally this parameter is installed automatically by that command when
1317 toggling the state to fullboth. If, however, you start Emacs in the
1318 fullboth state, you have to specify the desired behavior in your initial
1319 file as, for example
1322 (setq default-frame-alist
1323 '((fullscreen . fullboth) (fullscreen-restore . fullheight)))
1326 This will give a new frame full height after typing in it @key{F11} for
1331 @node Layout Parameters
1332 @subsubsection Layout Parameters
1333 @cindex layout parameters of frames
1334 @cindex frame layout parameters
1336 These frame parameters enable or disable various parts of the
1337 frame, or control their sizes.
1340 @vindex border-width, a frame parameter
1342 The width in pixels of the frame's border.
1344 @vindex internal-border-width, a frame parameter
1345 @item internal-border-width
1346 The distance in pixels between text (or fringe) and the frame's border.
1348 @vindex vertical-scroll-bars, a frame parameter
1349 @item vertical-scroll-bars
1350 Whether the frame has scroll bars for vertical scrolling, and which side
1351 of the frame they should be on. The possible values are @code{left},
1352 @code{right}, and @code{nil} for no scroll bars.
1354 @vindex horizontal-scroll-bars, a frame parameter
1355 @item horizontal-scroll-bars
1356 Whether the frame has scroll bars for horizontal scrolling (@code{t} and
1357 @code{bottom} mean yes, @code{nil} means no).
1359 @vindex scroll-bar-width, a frame parameter
1360 @item scroll-bar-width
1361 The width of vertical scroll bars, in pixels, or @code{nil} meaning to
1362 use the default width.
1364 @vindex scroll-bar-height, a frame parameter
1365 @item scroll-bar-height
1366 The height of horizontal scroll bars, in pixels, or @code{nil} meaning
1367 to use the default height.
1369 @vindex left-fringe, a frame parameter
1370 @vindex right-fringe, a frame parameter
1373 The default width of the left and right fringes of windows in this
1374 frame (@pxref{Fringes}). If either of these is zero, that effectively
1375 removes the corresponding fringe.
1377 When you use @code{frame-parameter} to query the value of either of
1378 these two frame parameters, the return value is always an integer.
1379 When using @code{set-frame-parameter}, passing a @code{nil} value
1380 imposes an actual default value of 8 pixels.
1382 @vindex right-divider-width, a frame parameter
1383 @item right-divider-width
1384 The width (thickness) reserved for the right divider (@pxref{Window
1385 Dividers}) of any window on the frame, in pixels. A value of zero means
1386 to not draw right dividers.
1388 @vindex bottom-divider-width, a frame parameter
1389 @item bottom-divider-width
1390 The width (thickness) reserved for the bottom divider (@pxref{Window
1391 Dividers}) of any window on the frame, in pixels. A value of zero means
1392 to not draw bottom dividers.
1394 @vindex menu-bar-lines frame parameter
1395 @item menu-bar-lines
1396 The number of lines to allocate at the top of the frame for a menu
1397 bar. The default is 1 if Menu Bar mode is enabled, and 0 otherwise.
1398 @xref{Menu Bars,,,emacs, The GNU Emacs Manual}.
1400 @vindex tool-bar-lines frame parameter
1401 @item tool-bar-lines
1402 The number of lines to use for the tool bar. The default is 1 if Tool
1403 Bar mode is enabled, and 0 otherwise. @xref{Tool Bars,,,emacs, The
1406 @vindex tool-bar-position frame parameter
1407 @item tool-bar-position
1408 The position of the tool bar. Currently only for the GTK tool bar.
1409 Value can be one of @code{top}, @code{bottom} @code{left}, @code{right}.
1410 The default is @code{top}.
1412 @vindex line-spacing, a frame parameter
1414 Additional space to leave below each text line, in pixels (a positive
1415 integer). @xref{Line Height}, for more information.
1418 @node Buffer Parameters
1419 @subsubsection Buffer Parameters
1420 @cindex frame, which buffers to display
1421 @cindex buffers to display on frame
1423 These frame parameters, meaningful on all kinds of terminals, deal
1424 with which buffers have been, or should, be displayed in the frame.
1427 @vindex minibuffer, a frame parameter
1429 Whether this frame has its own minibuffer. The value @code{t} means
1430 yes, @code{nil} means no, @code{only} means this frame is just a
1431 minibuffer. If the value is a minibuffer window (in some other
1432 frame), the frame uses that minibuffer.
1434 This frame parameter takes effect when the frame is created, and can
1435 not be changed afterwards.
1437 @vindex buffer-predicate, a frame parameter
1438 @item buffer-predicate
1439 The buffer-predicate function for this frame. The function
1440 @code{other-buffer} uses this predicate (from the selected frame) to
1441 decide which buffers it should consider, if the predicate is not
1442 @code{nil}. It calls the predicate with one argument, a buffer, once for
1443 each buffer; if the predicate returns a non-@code{nil} value, it
1444 considers that buffer.
1446 @vindex buffer-list, a frame parameter
1448 A list of buffers that have been selected in this frame, ordered
1449 most-recently-selected first.
1451 @vindex unsplittable, a frame parameter
1453 If non-@code{nil}, this frame's window is never split automatically.
1456 @node Management Parameters
1457 @subsubsection Window Management Parameters
1458 @cindex window manager interaction, and frame parameters
1460 The following frame parameters control various aspects of the
1461 frame's interaction with the window manager. They have no effect on
1465 @vindex visibility, a frame parameter
1467 The state of visibility of the frame. There are three possibilities:
1468 @code{nil} for invisible, @code{t} for visible, and @code{icon} for
1469 iconified. @xref{Visibility of Frames}.
1471 @vindex auto-raise, a frame parameter
1473 If non-@code{nil}, Emacs automatically raises the frame when it is
1474 selected. Some window managers do not allow this.
1476 @vindex auto-lower, a frame parameter
1478 If non-@code{nil}, Emacs automatically lowers the frame when it is
1479 deselected. Some window managers do not allow this.
1481 @vindex icon-type, a frame parameter
1483 The type of icon to use for this frame. If the value is a string,
1484 that specifies a file containing a bitmap to use; @code{nil} specifies
1485 no icon (in which case the window manager decides what to show); any
1486 other non-@code{nil} value specifies the default Emacs icon.
1488 @vindex icon-name, a frame parameter
1490 The name to use in the icon for this frame, when and if the icon
1491 appears. If this is @code{nil}, the frame's title is used.
1493 @vindex window-id, a frame parameter
1495 The ID number which the graphical display uses for this frame. Emacs
1496 assigns this parameter when the frame is created; changing the
1497 parameter has no effect on the actual ID number.
1499 @vindex outer-window-id, a frame parameter
1500 @item outer-window-id
1501 The ID number of the outermost window-system window in which the frame
1502 exists. As with @code{window-id}, changing this parameter has no
1505 @vindex wait-for-wm, a frame parameter
1507 If non-@code{nil}, tell Xt to wait for the window manager to confirm
1508 geometry changes. Some window managers, including versions of Fvwm2
1509 and KDE, fail to confirm, so Xt hangs. Set this to @code{nil} to
1510 prevent hanging with those window managers.
1512 @vindex sticky, a frame parameter
1514 If non-@code{nil}, the frame is visible on all virtual desktops on systems
1515 with virtual desktops.
1518 @vindex parent-id, a frame parameter
1520 @c ??? Not yet working.
1521 The X window number of the window that should be the parent of this one.
1522 Specifying this lets you create an Emacs window inside some other
1523 application's window. (It is not certain this will be implemented; try
1524 it and see if it works.)
1528 @node Cursor Parameters
1529 @subsubsection Cursor Parameters
1530 @cindex cursor, and frame parameters
1532 This frame parameter controls the way the cursor looks.
1535 @vindex cursor-type, a frame parameter
1537 How to display the cursor. Legitimate values are:
1541 Display a filled box. (This is the default.)
1543 Display a hollow box.
1545 Don't display a cursor.
1547 Display a vertical bar between characters.
1548 @item (bar . @var{width})
1549 Display a vertical bar @var{width} pixels wide between characters.
1551 Display a horizontal bar.
1552 @item (hbar . @var{height})
1553 Display a horizontal bar @var{height} pixels high.
1558 The @code{cursor-type} frame parameter may be overridden by the
1559 variables @code{cursor-type} and
1560 @code{cursor-in-non-selected-windows}:
1563 This buffer-local variable controls how the cursor looks in a selected
1564 window showing the buffer. If its value is @code{t}, that means to
1565 use the cursor specified by the @code{cursor-type} frame parameter.
1566 Otherwise, the value should be one of the cursor types listed above,
1567 and it overrides the @code{cursor-type} frame parameter.
1570 @defopt cursor-in-non-selected-windows
1571 This buffer-local variable controls how the cursor looks in a window
1572 that is not selected. It supports the same values as the
1573 @code{cursor-type} frame parameter; also, @code{nil} means don't
1574 display a cursor in nonselected windows, and @code{t} (the default)
1575 means use a standard modification of the usual cursor type (solid box
1576 becomes hollow box, and bar becomes a narrower bar).
1579 @defopt blink-cursor-alist
1580 This variable specifies how to blink the cursor. Each element has the
1581 form @code{(@var{on-state} . @var{off-state})}. Whenever the cursor
1582 type equals @var{on-state} (comparing using @code{equal}), the
1583 corresponding @var{off-state} specifies what the cursor looks like
1584 when it blinks off. Both @var{on-state} and @var{off-state}
1585 should be suitable values for the @code{cursor-type} frame parameter.
1587 There are various defaults for how to blink each type of cursor, if
1588 the type is not mentioned as an @var{on-state} here. Changes in this
1589 variable do not take effect immediately, only when you specify the
1590 @code{cursor-type} frame parameter.
1593 @node Font and Color Parameters
1594 @subsubsection Font and Color Parameters
1595 @cindex font and color, frame parameters
1597 These frame parameters control the use of fonts and colors.
1600 @vindex font-backend, a frame parameter
1602 A list of symbols, specifying the @dfn{font backends} to use for
1603 drawing fonts in the frame, in order of priority. On X, there are
1604 currently two available font backends: @code{x} (the X core font
1605 driver) and @code{xft} (the Xft font driver). On MS-Windows, there are
1606 currently two available font backends: @code{gdi} and
1607 @code{uniscribe} (@pxref{Windows Fonts,,, emacs, The GNU Emacs
1608 Manual}). On other systems, there is only one available font backend,
1609 so it does not make sense to modify this frame parameter.
1611 @vindex background-mode, a frame parameter
1612 @item background-mode
1613 This parameter is either @code{dark} or @code{light}, according
1614 to whether the background color is a light one or a dark one.
1616 @vindex tty-color-mode, a frame parameter
1617 @item tty-color-mode
1618 @cindex standard colors for character terminals
1619 This parameter overrides the terminal's color support as given by the
1620 system's terminal capabilities database in that this parameter's value
1621 specifies the color mode to use on a text terminal. The value can be
1622 either a symbol or a number. A number specifies the number of colors
1623 to use (and, indirectly, what commands to issue to produce each
1624 color). For example, @code{(tty-color-mode . 8)} specifies use of the
1625 ANSI escape sequences for 8 standard text colors. A value of -1 turns
1628 If the parameter's value is a symbol, it specifies a number through
1629 the value of @code{tty-color-mode-alist}, and the associated number is
1632 @vindex screen-gamma, a frame parameter
1634 @cindex gamma correction
1635 If this is a number, Emacs performs gamma correction which adjusts
1636 the brightness of all colors. The value should be the screen gamma of
1639 Usual PC monitors have a screen gamma of 2.2, so color values in
1640 Emacs, and in X windows generally, are calibrated to display properly
1641 on a monitor with that gamma value. If you specify 2.2 for
1642 @code{screen-gamma}, that means no correction is needed. Other values
1643 request correction, designed to make the corrected colors appear on
1644 your screen the way they would have appeared without correction on an
1645 ordinary monitor with a gamma value of 2.2.
1647 If your monitor displays colors too light, you should specify a
1648 @code{screen-gamma} value smaller than 2.2. This requests correction
1649 that makes colors darker. A screen gamma value of 1.5 may give good
1650 results for LCD color displays.
1652 @vindex alpha, a frame parameter
1654 @cindex opacity, frame
1655 @cindex transparency, frame
1656 @vindex frame-alpha-lower-limit
1657 This parameter specifies the opacity of the frame, on graphical
1658 displays that support variable opacity. It should be an integer
1659 between 0 and 100, where 0 means completely transparent and 100 means
1660 completely opaque. It can also have a @code{nil} value, which tells
1661 Emacs not to set the frame opacity (leaving it to the window manager).
1663 To prevent the frame from disappearing completely from view, the
1664 variable @code{frame-alpha-lower-limit} defines a lower opacity limit.
1665 If the value of the frame parameter is less than the value of this
1666 variable, Emacs uses the latter. By default,
1667 @code{frame-alpha-lower-limit} is 20.
1669 The @code{alpha} frame parameter can also be a cons cell
1670 @code{(@var{active} . @var{inactive})}, where @var{active} is the
1671 opacity of the frame when it is selected, and @var{inactive} is the
1672 opacity when it is not selected.
1675 The following frame parameters are semi-obsolete in that they are
1676 automatically equivalent to particular face attributes of particular
1677 faces (@pxref{Standard Faces,,, emacs, The Emacs Manual}):
1680 @vindex font, a frame parameter
1682 The name of the font for displaying text in the frame. This is a
1683 string, either a valid font name for your system or the name of an Emacs
1684 fontset (@pxref{Fontsets}). It is equivalent to the @code{font}
1685 attribute of the @code{default} face.
1687 @vindex foreground-color, a frame parameter
1688 @item foreground-color
1689 The color to use for the image of a character. It is equivalent to
1690 the @code{:foreground} attribute of the @code{default} face.
1692 @vindex background-color, a frame parameter
1693 @item background-color
1694 The color to use for the background of characters. It is equivalent to
1695 the @code{:background} attribute of the @code{default} face.
1697 @vindex mouse-color, a frame parameter
1699 The color for the mouse pointer. It is equivalent to the @code{:background}
1700 attribute of the @code{mouse} face.
1702 @vindex cursor-color, a frame parameter
1704 The color for the cursor that shows point. It is equivalent to the
1705 @code{:background} attribute of the @code{cursor} face.
1707 @vindex border-color, a frame parameter
1709 The color for the border of the frame. It is equivalent to the
1710 @code{:background} attribute of the @code{border} face.
1712 @vindex scroll-bar-foreground, a frame parameter
1713 @item scroll-bar-foreground
1714 If non-@code{nil}, the color for the foreground of scroll bars. It is
1715 equivalent to the @code{:foreground} attribute of the
1716 @code{scroll-bar} face.
1718 @vindex scroll-bar-background, a frame parameter
1719 @item scroll-bar-background
1720 If non-@code{nil}, the color for the background of scroll bars. It is
1721 equivalent to the @code{:background} attribute of the
1722 @code{scroll-bar} face.
1727 @subsection Geometry
1729 Here's how to examine the data in an X-style window geometry
1732 @defun x-parse-geometry geom
1733 @cindex geometry specification
1734 The function @code{x-parse-geometry} converts a standard X window
1735 geometry string to an alist that you can use as part of the argument to
1738 The alist describes which parameters were specified in @var{geom}, and
1739 gives the values specified for them. Each element looks like
1740 @code{(@var{parameter} . @var{value})}. The possible @var{parameter}
1741 values are @code{left}, @code{top}, @code{width}, and @code{height}.
1743 For the size parameters, the value must be an integer. The position
1744 parameter names @code{left} and @code{top} are not totally accurate,
1745 because some values indicate the position of the right or bottom edges
1746 instead. The @var{value} possibilities for the position parameters are:
1747 an integer, a list @code{(+ @var{pos})}, or a list @code{(- @var{pos})};
1748 as previously described (@pxref{Position Parameters}).
1753 (x-parse-geometry "35x70+0-0")
1754 @result{} ((height . 70) (width . 35)
1755 (top - 0) (left . 0))
1759 @node Terminal Parameters
1760 @section Terminal Parameters
1761 @cindex terminal parameters
1763 Each terminal has a list of associated parameters. These
1764 @dfn{terminal parameters} are mostly a convenient way of storage for
1765 terminal-local variables, but some terminal parameters have a special
1768 This section describes functions to read and change the parameter values
1769 of a terminal. They all accept as their argument either a terminal or
1770 a frame; the latter means use that frame's terminal. An argument of
1771 @code{nil} means the selected frame's terminal.
1773 @defun terminal-parameters &optional terminal
1774 This function returns an alist listing all the parameters of
1775 @var{terminal} and their values.
1778 @defun terminal-parameter terminal parameter
1779 This function returns the value of the parameter @var{parameter} (a
1780 symbol) of @var{terminal}. If @var{terminal} has no setting for
1781 @var{parameter}, this function returns @code{nil}.
1784 @defun set-terminal-parameter terminal parameter value
1785 This function sets the parameter @var{parameter} of @var{terminal} to the
1786 specified @var{value}, and returns the previous value of that
1790 Here's a list of a few terminal parameters that have a special
1794 @item background-mode
1795 The classification of the terminal's background color, either
1796 @code{light} or @code{dark}.
1797 @item normal-erase-is-backspace
1798 Value is either 1 or 0, depending on whether
1799 @code{normal-erase-is-backspace-mode} is turned on or off on this
1800 terminal. @xref{DEL Does Not Delete,,, emacs, The Emacs Manual}.
1801 @item terminal-initted
1802 After the terminal is initialized, this is set to the
1803 terminal-specific initialization function.
1804 @item tty-mode-set-strings
1805 When present, a list of strings containing escape sequences that Emacs
1806 will output while configuring a tty for rendering. Emacs emits these
1807 strings only when configuring a terminal: if you want to enable a mode
1808 on a terminal that is already active (for example, while in
1809 @code{tty-setup-hook}), explicitly output the necessary escape
1810 sequence using @code{send-string-to-terminal} in addition to adding
1811 the sequence to @code{tty-mode-set-strings}.
1812 @item tty-mode-reset-strings
1813 When present, a list of strings that undo the effects of the strings
1814 in @code{tty-mode-set-strings}. Emacs emits these strings when
1815 exiting, deleting a terminal, or suspending itself.
1819 @section Frame Titles
1822 Every frame has a @code{name} parameter; this serves as the default
1823 for the frame title which window systems typically display at the top of
1824 the frame. You can specify a name explicitly by setting the @code{name}
1827 Normally you don't specify the name explicitly, and Emacs computes the
1828 frame name automatically based on a template stored in the variable
1829 @code{frame-title-format}. Emacs recomputes the name each time the
1830 frame is redisplayed.
1832 @defvar frame-title-format
1833 This variable specifies how to compute a name for a frame when you have
1834 not explicitly specified one. The variable's value is actually a mode
1835 line construct, just like @code{mode-line-format}, except that the
1836 @samp{%c} and @samp{%l} constructs are ignored. @xref{Mode Line
1840 @defvar icon-title-format
1841 This variable specifies how to compute the name for an iconified frame,
1842 when you have not explicitly specified the frame title. This title
1843 appears in the icon itself.
1846 @defvar multiple-frames
1847 This variable is set automatically by Emacs. Its value is @code{t} when
1848 there are two or more frames (not counting minibuffer-only frames or
1849 invisible frames). The default value of @code{frame-title-format} uses
1850 @code{multiple-frames} so as to put the buffer name in the frame title
1851 only when there is more than one frame.
1853 The value of this variable is not guaranteed to be accurate except
1854 while processing @code{frame-title-format} or
1855 @code{icon-title-format}.
1858 @node Deleting Frames
1859 @section Deleting Frames
1860 @cindex deleting frames
1862 A @dfn{live frame} is one that has not been deleted. When a frame
1863 is deleted, it is removed from its terminal display, although it may
1864 continue to exist as a Lisp object until there are no more references
1867 @deffn Command delete-frame &optional frame force
1868 @vindex delete-frame-functions
1869 This function deletes the frame @var{frame}. Unless @var{frame} is a
1870 tooltip, it first runs the hook @code{delete-frame-functions} (each
1871 function gets one argument, @var{frame}). By default, @var{frame} is
1874 A frame cannot be deleted as long as its minibuffer serves as surrogate
1875 minibuffer for another frame (@pxref{Minibuffers and Frames}).
1876 Normally, you cannot delete a frame if all other frames are invisible,
1877 but if @var{force} is non-@code{nil}, then you are allowed to do so.
1880 @defun frame-live-p frame
1881 The function @code{frame-live-p} returns non-@code{nil} if the frame
1882 @var{frame} has not been deleted. The possible non-@code{nil} return
1883 values are like those of @code{framep}. @xref{Frames}.
1886 Some window managers provide a command to delete a window. These work
1887 by sending a special message to the program that operates the window.
1888 When Emacs gets one of these commands, it generates a
1889 @code{delete-frame} event, whose normal definition is a command that
1890 calls the function @code{delete-frame}. @xref{Misc Events}.
1892 @node Finding All Frames
1893 @section Finding All Frames
1894 @cindex frames, scanning all
1897 This function returns a list of all the live frames, i.e., those that
1898 have not been deleted. It is analogous to @code{buffer-list} for
1899 buffers, and includes frames on all terminals. The list that you get
1900 is newly created, so modifying the list doesn't have any effect on the
1904 @defun visible-frame-list
1905 This function returns a list of just the currently visible frames.
1906 @xref{Visibility of Frames}. Frames on text terminals always count as
1907 visible, even though only the selected one is actually displayed.
1910 @defun next-frame &optional frame minibuf
1911 This function lets you cycle conveniently through all the frames on
1912 the current display from an arbitrary starting point. It returns the
1913 next frame after @var{frame} in the cycle. If @var{frame} is
1914 omitted or @code{nil}, it defaults to the selected frame (@pxref{Input
1917 The second argument, @var{minibuf}, says which frames to consider:
1921 Exclude minibuffer-only frames.
1922 @item @code{visible}
1923 Consider all visible frames.
1925 Consider all visible or iconified frames.
1927 Consider only the frames using that particular window as their
1930 Consider all frames.
1934 @defun previous-frame &optional frame minibuf
1935 Like @code{next-frame}, but cycles through all frames in the opposite
1939 See also @code{next-window} and @code{previous-window}, in @ref{Cyclic
1942 @node Minibuffers and Frames
1943 @section Minibuffers and Frames
1945 Normally, each frame has its own minibuffer window at the bottom, which
1946 is used whenever that frame is selected. If the frame has a minibuffer,
1947 you can get it with @code{minibuffer-window} (@pxref{Definition of
1948 minibuffer-window}).
1950 @cindex frame without a minibuffer
1951 @cindex surrogate minibuffer frame
1952 However, you can also create a frame without a minibuffer. Such a frame
1953 must use the minibuffer window of some other frame. That other frame
1954 will serve as @dfn{surrogate minibuffer frame} for this frame and cannot
1955 be deleted via @code{delete-frame} (@pxref{Deleting Frames}) as long as
1958 When you create the frame, you can explicitly specify the minibuffer
1959 window to use (in some other frame). If you don't, then the minibuffer
1960 is found in the frame which is the value of the variable
1961 @code{default-minibuffer-frame}. Its value should be a frame that does
1964 If you use a minibuffer-only frame, you might want that frame to raise
1965 when you enter the minibuffer. If so, set the variable
1966 @code{minibuffer-auto-raise} to @code{t}. @xref{Raising and Lowering}.
1968 @defvar default-minibuffer-frame
1969 This variable specifies the frame to use for the minibuffer window, by
1970 default. It does not affect existing frames. It is always local to
1971 the current terminal and cannot be buffer-local. @xref{Multiple
1976 @section Input Focus
1978 @c @cindex selected frame Duplicates selected-frame, same for selected-window.
1980 At any time, one frame in Emacs is the @dfn{selected frame}. The selected
1981 window always resides on the selected frame.
1983 When Emacs displays its frames on several terminals (@pxref{Multiple
1984 Terminals}), each terminal has its own selected frame. But only one
1985 of these is @emph{the} selected frame: it's the frame that belongs
1986 to the terminal from which the most recent input came. That is, when
1987 Emacs runs a command that came from a certain terminal, the selected
1988 frame is the one of that terminal. Since Emacs runs only a single
1989 command at any given time, it needs to consider only one selected
1990 frame at a time; this frame is what we call @dfn{the selected frame}
1991 in this manual. The display on which the selected frame is shown is
1992 the @dfn{selected frame's display}.
1994 @defun selected-frame
1995 This function returns the selected frame.
1998 Some window systems and window managers direct keyboard input to the
1999 window object that the mouse is in; others require explicit clicks or
2000 commands to @dfn{shift the focus} to various window objects. Either
2001 way, Emacs automatically keeps track of which frame has the focus. To
2002 explicitly switch to a different frame from a Lisp function, call
2003 @code{select-frame-set-input-focus}.
2005 Lisp programs can also switch frames temporarily by calling the
2006 function @code{select-frame}. This does not alter the window system's
2007 concept of focus; rather, it escapes from the window manager's control
2008 until that control is somehow reasserted.
2010 When using a text terminal, only one frame can be displayed at a time
2011 on the terminal, so after a call to @code{select-frame}, the next
2012 redisplay actually displays the newly selected frame. This frame
2013 remains selected until a subsequent call to @code{select-frame}. Each
2014 frame on a text terminal has a number which appears in the mode line
2015 before the buffer name (@pxref{Mode Line Variables}).
2017 @defun select-frame-set-input-focus frame &optional norecord
2018 This function selects @var{frame}, raises it (should it happen to be
2019 obscured by other frames) and tries to give it the X server's focus.
2020 On a text terminal, the next redisplay displays the new frame on the
2021 entire terminal screen. The optional argument @var{norecord} has the
2022 same meaning as for @code{select-frame} (see below). The return value
2023 of this function is not significant.
2026 @deffn Command select-frame frame &optional norecord
2027 This function selects frame @var{frame}, temporarily disregarding the
2028 focus of the X server if any. The selection of @var{frame} lasts until
2029 the next time the user does something to select a different frame, or
2030 until the next time this function is called. (If you are using a
2031 window system, the previously selected frame may be restored as the
2032 selected frame after return to the command loop, because it still may
2033 have the window system's input focus.)
2035 The specified @var{frame} becomes the selected frame, and its terminal
2036 becomes the selected terminal. This function then calls
2037 @code{select-window} as a subroutine, passing the window selected
2038 within @var{frame} as its first argument and @var{norecord} as its
2039 second argument (hence, if @var{norecord} is non-@code{nil}, this
2040 avoids changing the order of recently selected windows nor the buffer
2041 list). @xref{Selecting Windows}.
2043 This function returns @var{frame}, or @code{nil} if @var{frame} has
2046 In general, you should never use @code{select-frame} in a way that
2047 could switch to a different terminal without switching back when
2051 Emacs cooperates with the window system by arranging to select frames as
2052 the server and window manager request. It does so by generating a
2053 special kind of input event, called a @dfn{focus} event, when
2054 appropriate. The command loop handles a focus event by calling
2055 @code{handle-switch-frame}. @xref{Focus Events}.
2057 @deffn Command handle-switch-frame frame
2058 This function handles a focus event by selecting frame @var{frame}.
2060 Focus events normally do their job by invoking this command.
2061 Don't call it for any other reason.
2064 @defun redirect-frame-focus frame &optional focus-frame
2065 This function redirects focus from @var{frame} to @var{focus-frame}.
2066 This means that @var{focus-frame} will receive subsequent keystrokes and
2067 events intended for @var{frame}. After such an event, the value of
2068 @code{last-event-frame} will be @var{focus-frame}. Also, switch-frame
2069 events specifying @var{frame} will instead select @var{focus-frame}.
2071 If @var{focus-frame} is omitted or @code{nil}, that cancels any existing
2072 redirection for @var{frame}, which therefore once again receives its own
2075 One use of focus redirection is for frames that don't have minibuffers.
2076 These frames use minibuffers on other frames. Activating a minibuffer
2077 on another frame redirects focus to that frame. This puts the focus on
2078 the minibuffer's frame, where it belongs, even though the mouse remains
2079 in the frame that activated the minibuffer.
2081 Selecting a frame can also change focus redirections. Selecting frame
2082 @code{bar}, when @code{foo} had been selected, changes any redirections
2083 pointing to @code{foo} so that they point to @code{bar} instead. This
2084 allows focus redirection to work properly when the user switches from
2085 one frame to another using @code{select-window}.
2087 This means that a frame whose focus is redirected to itself is treated
2088 differently from a frame whose focus is not redirected.
2089 @code{select-frame} affects the former but not the latter.
2091 The redirection lasts until @code{redirect-frame-focus} is called to
2095 @defvar focus-in-hook
2096 This is a normal hook run when an Emacs frame gains input focus.
2099 @defvar focus-out-hook
2100 This is a normal hook run when an Emacs frame loses input focus.
2103 @defopt focus-follows-mouse
2104 This option is how you inform Emacs whether the window manager transfers
2105 focus when the user moves the mouse. Non-@code{nil} says that it does.
2106 When this is so, the command @code{other-frame} moves the mouse to a
2107 position consistent with the new selected frame.
2110 @node Visibility of Frames
2111 @section Visibility of Frames
2112 @cindex visible frame
2113 @cindex invisible frame
2114 @cindex iconified frame
2115 @cindex minimized frame
2116 @cindex frame visibility
2118 A frame on a graphical display may be @dfn{visible}, @dfn{invisible},
2119 or @dfn{iconified}. If it is visible, its contents are displayed in
2120 the usual manner. If it is iconified, its contents are not displayed,
2121 but there is a little icon somewhere to bring the frame back into view
2122 (some window managers refer to this state as @dfn{minimized} rather
2123 than @dfn{iconified}, but from Emacs' point of view they are the same
2124 thing). If a frame is invisible, it is not displayed at all.
2126 Visibility is meaningless on text terminals, since only the selected
2127 one is actually displayed in any case.
2129 @defun frame-visible-p frame
2130 This function returns the visibility status of frame @var{frame}. The
2131 value is @code{t} if @var{frame} is visible, @code{nil} if it is
2132 invisible, and @code{icon} if it is iconified.
2134 On a text terminal, all frames are considered visible for the
2135 purposes of this function, even though only one frame is displayed.
2136 @xref{Raising and Lowering}.
2139 @deffn Command iconify-frame &optional frame
2140 This function iconifies frame @var{frame}. If you omit @var{frame}, it
2141 iconifies the selected frame.
2144 @deffn Command make-frame-visible &optional frame
2145 This function makes frame @var{frame} visible. If you omit
2146 @var{frame}, it makes the selected frame visible. This does not raise
2147 the frame, but you can do that with @code{raise-frame} if you wish
2148 (@pxref{Raising and Lowering}).
2151 @deffn Command make-frame-invisible &optional frame force
2152 This function makes frame @var{frame} invisible. If you omit
2153 @var{frame}, it makes the selected frame invisible.
2155 Unless @var{force} is non-@code{nil}, this function refuses to make
2156 @var{frame} invisible if all other frames are invisible..
2159 The visibility status of a frame is also available as a frame
2160 parameter. You can read or change it as such. @xref{Management
2161 Parameters}. The user can also iconify and deiconify frames with the
2162 window manager. This happens below the level at which Emacs can exert
2163 any control, but Emacs does provide events that you can use to keep
2164 track of such changes. @xref{Misc Events}.
2166 @node Raising and Lowering
2167 @section Raising and Lowering Frames
2169 @cindex raising a frame
2170 @cindex lowering a frame
2171 Most window systems use a desktop metaphor. Part of this metaphor
2172 is the idea that system-level windows (e.g., Emacs frames) are
2173 stacked in a notional third dimension perpendicular to the screen
2174 surface. Where two overlap, the one higher up covers the one
2175 underneath. You can @dfn{raise} or @dfn{lower} a frame using the
2176 functions @code{raise-frame} and @code{lower-frame}.
2178 @deffn Command raise-frame &optional frame
2179 This function raises frame @var{frame} (default, the selected frame).
2180 If @var{frame} is invisible or iconified, this makes it visible.
2183 @deffn Command lower-frame &optional frame
2184 This function lowers frame @var{frame} (default, the selected frame).
2187 @defopt minibuffer-auto-raise
2188 If this is non-@code{nil}, activation of the minibuffer raises the frame
2189 that the minibuffer window is in.
2192 On window systems, you can also enable auto-raising (on frame
2193 selection) or auto-lowering (on frame deselection) using frame
2194 parameters. @xref{Management Parameters}.
2197 The concept of raising and lowering frames also applies to text
2198 terminal frames. On each text terminal, only the top frame is
2199 displayed at any one time.
2201 @defun tty-top-frame terminal
2202 This function returns the top frame on @var{terminal}. @var{terminal}
2203 should be a terminal object, a frame (meaning that frame's terminal),
2204 or @code{nil} (meaning the selected frame's terminal). If it does not
2205 refer to a text terminal, the return value is @code{nil}.
2208 @node Frame Configurations
2209 @section Frame Configurations
2210 @cindex frame configuration
2212 A @dfn{frame configuration} records the current arrangement of frames,
2213 all their properties, and the window configuration of each one.
2214 (@xref{Window Configurations}.)
2216 @defun current-frame-configuration
2217 This function returns a frame configuration list that describes
2218 the current arrangement of frames and their contents.
2221 @defun set-frame-configuration configuration &optional nodelete
2222 This function restores the state of frames described in
2223 @var{configuration}. However, this function does not restore deleted
2226 Ordinarily, this function deletes all existing frames not listed in
2227 @var{configuration}. But if @var{nodelete} is non-@code{nil}, the
2228 unwanted frames are iconified instead.
2231 @node Mouse Tracking
2232 @section Mouse Tracking
2233 @cindex mouse tracking
2234 @c @cindex tracking the mouse Duplicates track-mouse
2236 Sometimes it is useful to @dfn{track} the mouse, which means to display
2237 something to indicate where the mouse is and move the indicator as the
2238 mouse moves. For efficient mouse tracking, you need a way to wait until
2239 the mouse actually moves.
2241 The convenient way to track the mouse is to ask for events to represent
2242 mouse motion. Then you can wait for motion by waiting for an event. In
2243 addition, you can easily handle any other sorts of events that may
2244 occur. That is useful, because normally you don't want to track the
2245 mouse forever---only until some other event, such as the release of a
2248 @defspec track-mouse body@dots{}
2249 This special form executes @var{body}, with generation of mouse motion
2250 events enabled. Typically, @var{body} would use @code{read-event} to
2251 read the motion events and modify the display accordingly. @xref{Motion
2252 Events}, for the format of mouse motion events.
2254 The value of @code{track-mouse} is that of the last form in @var{body}.
2255 You should design @var{body} to return when it sees the up-event that
2256 indicates the release of the button, or whatever kind of event means
2257 it is time to stop tracking.
2259 The @code{track-mouse} form causes Emacs to generate mouse motion
2260 events by binding the variable @code{track-mouse} to a
2261 non-@code{nil} value. If that variable has the special value
2262 @code{dragging}, it additionally instructs the display engine to
2263 refrain from changing the shape of the mouse pointer. This is
2264 desirable in Lisp programs that require mouse dragging across large
2265 portions of Emacs display, which might otherwise cause the mouse
2266 pointer to change its shape according to the display portion it hovers
2267 on (@pxref{Pointer Shape}). Therefore, Lisp programs that need the
2268 mouse pointer to retain its original shape during dragging should bind
2269 @code{track-mouse} to the value @code{dragging} at the beginning of
2273 The usual purpose of tracking mouse motion is to indicate on the screen
2274 the consequences of pushing or releasing a button at the current
2277 In many cases, you can avoid the need to track the mouse by using
2278 the @code{mouse-face} text property (@pxref{Special Properties}).
2279 That works at a much lower level and runs more smoothly than
2280 Lisp-level mouse tracking.
2283 @c These are not implemented yet.
2285 These functions change the screen appearance instantaneously. The
2286 effect is transient, only until the next ordinary Emacs redisplay. That
2287 is OK for mouse tracking, since it doesn't make sense for mouse tracking
2288 to change the text, and the body of @code{track-mouse} normally reads
2289 the events itself and does not do redisplay.
2291 @defun x-contour-region window beg end
2292 This function draws lines to make a box around the text from @var{beg}
2293 to @var{end}, in window @var{window}.
2296 @defun x-uncontour-region window beg end
2297 This function erases the lines that would make a box around the text
2298 from @var{beg} to @var{end}, in window @var{window}. Use it to remove
2299 a contour that you previously made by calling @code{x-contour-region}.
2302 @defun x-draw-rectangle frame left top right bottom
2303 This function draws a hollow rectangle on frame @var{frame} with the
2304 specified edge coordinates, all measured in pixels from the inside top
2305 left corner. It uses the cursor color, the one used for indicating the
2309 @defun x-erase-rectangle frame left top right bottom
2310 This function erases a hollow rectangle on frame @var{frame} with the
2311 specified edge coordinates, all measured in pixels from the inside top
2312 left corner. Erasure means redrawing the text and background that
2313 normally belong in the specified rectangle.
2317 @node Mouse Position
2318 @section Mouse Position
2319 @cindex mouse position
2320 @cindex position of mouse
2322 The functions @code{mouse-position} and @code{set-mouse-position}
2323 give access to the current position of the mouse.
2325 @defun mouse-position
2326 This function returns a description of the position of the mouse. The
2327 value looks like @code{(@var{frame} @var{x} . @var{y})}, where @var{x}
2328 and @var{y} are integers giving the (possibly rounded) position in
2329 multiples of the default character size of @var{frame} (@pxref{Frame
2330 Font}) relative to the native position of @var{frame} (@pxref{Frame
2334 @defvar mouse-position-function
2335 If non-@code{nil}, the value of this variable is a function for
2336 @code{mouse-position} to call. @code{mouse-position} calls this
2337 function just before returning, with its normal return value as the
2338 sole argument, and it returns whatever this function returns to it.
2340 This abnormal hook exists for the benefit of packages like
2341 @file{xt-mouse.el} that need to do mouse handling at the Lisp level.
2344 @defun set-mouse-position frame x y
2345 This function @dfn{warps the mouse} to position @var{x}, @var{y} in
2346 frame @var{frame}. The arguments @var{x} and @var{y} are integers,
2347 giving the position in multiples of the default character size of
2348 @var{frame} (@pxref{Frame Font}) relative to the native position of
2349 @var{frame} (@pxref{Frame Geometry}).
2351 The resulting mouse position is constrained to the native frame of
2352 @var{frame}. If @var{frame} is not visible, this function does nothing.
2353 The return value is not significant.
2356 @defun mouse-pixel-position
2357 This function is like @code{mouse-position} except that it returns
2358 coordinates in units of pixels rather than units of characters.
2361 @defun set-mouse-pixel-position frame x y
2362 This function warps the mouse like @code{set-mouse-position} except that
2363 @var{x} and @var{y} are in units of pixels rather than units of
2366 The resulting mouse position is not constrained to the native frame of
2367 @var{frame}. If @var{frame} is not visible, this function does nothing.
2368 The return value is not significant.
2371 On a graphical terminal the following two functions allow to retrieve
2372 and set the absolute position of the mouse cursor.
2374 @defun mouse-absolute-pixel-position
2375 This function returns a cons cell (@var{x} . @var{y}) of the coordinates
2376 of the mouse cursor position in pixels, relative to a position (0, 0) of
2377 the selected frame's display.
2380 @defun set-mouse-absolute-pixel-position x y
2381 This function moves the mouse cursor to the position (@var{x}, @var{y}).
2382 The coordinates @var{x} and @var{y} are interpreted in pixels relative
2383 to a position (0, 0) of the selected frame's display.
2386 The following function can tell whether the mouse cursor is currently
2389 @defun frame-pointer-visible-p &optional frame
2390 This predicate function returns non-@code{nil} if the mouse pointer
2391 displayed on @var{frame} is visible; otherwise it returns @code{nil}.
2392 @var{frame} omitted or @code{nil} means the selected frame. This is
2393 useful when @code{make-pointer-invisible} is set to @code{t}: it
2394 allows to know if the pointer has been hidden.
2395 @xref{Mouse Avoidance,,,emacs, The Emacs Manual}.
2401 @section Pop-Up Menus
2402 @cindex menus, popup
2404 A Lisp program can pop up a menu so that the user can choose an
2405 alternative with the mouse. On a text terminal, if the mouse is not
2406 available, the user can choose an alternative using the keyboard
2407 motion keys---@kbd{C-n}, @kbd{C-p}, or up- and down-arrow keys.
2409 @defun x-popup-menu position menu
2410 This function displays a pop-up menu and returns an indication of
2411 what selection the user makes.
2413 The argument @var{position} specifies where on the screen to put the
2414 top left corner of the menu. It can be either a mouse button event
2415 (which says to put the menu where the user actuated the button) or a
2419 ((@var{xoffset} @var{yoffset}) @var{window})
2423 where @var{xoffset} and @var{yoffset} are coordinates, measured in
2424 pixels, counting from the top left corner of @var{window}. @var{window}
2425 may be a window or a frame.
2427 If @var{position} is @code{t}, it means to use the current mouse
2428 position (or the top-left corner of the frame if the mouse is not
2429 available on a text terminal). If @var{position} is @code{nil}, it
2430 means to precompute the key binding equivalents for the keymaps
2431 specified in @var{menu}, without actually displaying or popping up the
2434 The argument @var{menu} says what to display in the menu. It can be a
2435 keymap or a list of keymaps (@pxref{Menu Keymaps}). In this case, the
2436 return value is the list of events corresponding to the user's choice.
2437 This list has more than one element if the choice occurred in a
2438 submenu. (Note that @code{x-popup-menu} does not actually execute the
2439 command bound to that sequence of events.) On text terminals and
2440 toolkits that support menu titles, the title is taken from the prompt
2441 string of @var{menu} if @var{menu} is a keymap, or from the prompt
2442 string of the first keymap in @var{menu} if it is a list of keymaps
2443 (@pxref{Defining Menus}).
2445 Alternatively, @var{menu} can have the following form:
2448 (@var{title} @var{pane1} @var{pane2}...)
2452 where each pane is a list of form
2455 (@var{title} @var{item1} @var{item2}...)
2458 Each @var{item} should be a cons cell, @code{(@var{line} . @var{value})},
2459 where @var{line} is a string and @var{value} is the value to return if
2460 that @var{line} is chosen. Unlike in a menu keymap, a @code{nil}
2461 @var{value} does not make the menu item non-selectable.
2462 Alternatively, each @var{item} can be a string rather than a cons
2463 cell; this makes a non-selectable menu item.
2465 If the user gets rid of the menu without making a valid choice, for
2466 instance by clicking the mouse away from a valid choice or by typing
2467 @kbd{C-g}, then this normally results in a quit and
2468 @code{x-popup-menu} does not return. But if @var{position} is a mouse
2469 button event (indicating that the user invoked the menu with the
2470 mouse) then no quit occurs and @code{x-popup-menu} returns @code{nil}.
2473 @strong{Usage note:} Don't use @code{x-popup-menu} to display a menu
2474 if you could do the job with a prefix key defined with a menu keymap.
2475 If you use a menu keymap to implement a menu, @kbd{C-h c} and @kbd{C-h
2476 a} can see the individual items in that menu and provide help for them.
2477 If instead you implement the menu by defining a command that calls
2478 @code{x-popup-menu}, the help facilities cannot know what happens inside
2479 that command, so they cannot give any help for the menu's items.
2481 The menu bar mechanism, which lets you switch between submenus by
2482 moving the mouse, cannot look within the definition of a command to see
2483 that it calls @code{x-popup-menu}. Therefore, if you try to implement a
2484 submenu using @code{x-popup-menu}, it cannot work with the menu bar in
2485 an integrated fashion. This is why all menu bar submenus are
2486 implemented with menu keymaps within the parent menu, and never with
2487 @code{x-popup-menu}. @xref{Menu Bar}.
2489 If you want a menu bar submenu to have contents that vary, you should
2490 still use a menu keymap to implement it. To make the contents vary, add
2491 a hook function to @code{menu-bar-update-hook} to update the contents of
2492 the menu keymap as necessary.
2495 @section Dialog Boxes
2496 @cindex dialog boxes
2498 A dialog box is a variant of a pop-up menu---it looks a little
2499 different, it always appears in the center of a frame, and it has just
2500 one level and one or more buttons. The main use of dialog boxes is
2501 for asking questions that the user can answer with ``yes'', ``no'',
2502 and a few other alternatives. With a single button, they can also
2503 force the user to acknowledge important information. The functions
2504 @code{y-or-n-p} and @code{yes-or-no-p} use dialog boxes instead of the
2505 keyboard, when called from commands invoked by mouse clicks.
2507 @defun x-popup-dialog position contents &optional header
2508 This function displays a pop-up dialog box and returns an indication of
2509 what selection the user makes. The argument @var{contents} specifies
2510 the alternatives to offer; it has this format:
2513 (@var{title} (@var{string} . @var{value})@dots{})
2517 which looks like the list that specifies a single pane for
2518 @code{x-popup-menu}.
2520 The return value is @var{value} from the chosen alternative.
2522 As for @code{x-popup-menu}, an element of the list may be just a
2523 string instead of a cons cell @code{(@var{string} . @var{value})}.
2524 That makes a box that cannot be selected.
2526 If @code{nil} appears in the list, it separates the left-hand items from
2527 the right-hand items; items that precede the @code{nil} appear on the
2528 left, and items that follow the @code{nil} appear on the right. If you
2529 don't include a @code{nil} in the list, then approximately half the
2530 items appear on each side.
2532 Dialog boxes always appear in the center of a frame; the argument
2533 @var{position} specifies which frame. The possible values are as in
2534 @code{x-popup-menu}, but the precise coordinates or the individual
2535 window don't matter; only the frame matters.
2537 If @var{header} is non-@code{nil}, the frame title for the box is
2538 @samp{Information}, otherwise it is @samp{Question}. The former is used
2539 for @code{message-box} (@pxref{message-box}). (On text terminals, the
2540 box title is not displayed.)
2542 In some configurations, Emacs cannot display a real dialog box; so
2543 instead it displays the same items in a pop-up menu in the center of the
2546 If the user gets rid of the dialog box without making a valid choice,
2547 for instance using the window manager, then this produces a quit and
2548 @code{x-popup-dialog} does not return.
2552 @section Pointer Shape
2553 @cindex pointer shape
2554 @cindex mouse pointer shape
2556 You can specify the mouse pointer style for particular text or
2557 images using the @code{pointer} text property, and for images with the
2558 @code{:pointer} and @code{:map} image properties. The values you can
2559 use in these properties are @code{text} (or @code{nil}), @code{arrow},
2560 @code{hand}, @code{vdrag}, @code{hdrag}, @code{modeline}, and
2561 @code{hourglass}. @code{text} stands for the usual mouse pointer
2562 style used over text.
2564 Over void parts of the window (parts that do not correspond to any
2565 of the buffer contents), the mouse pointer usually uses the
2566 @code{arrow} style, but you can specify a different style (one of
2567 those above) by setting @code{void-text-area-pointer}.
2569 @defopt void-text-area-pointer
2570 This variable specifies the mouse pointer style for void text areas.
2571 These include the areas after the end of a line or below the last line
2572 in the buffer. The default is to use the @code{arrow} (non-text)
2576 When using X, you can specify what the @code{text} pointer style
2577 really looks like by setting the variable @code{x-pointer-shape}.
2579 @defvar x-pointer-shape
2580 This variable specifies the pointer shape to use ordinarily in the
2581 Emacs frame, for the @code{text} pointer style.
2584 @defvar x-sensitive-text-pointer-shape
2585 This variable specifies the pointer shape to use when the mouse
2586 is over mouse-sensitive text.
2589 These variables affect newly created frames. They do not normally
2590 affect existing frames; however, if you set the mouse color of a
2591 frame, that also installs the current value of those two variables.
2592 @xref{Font and Color Parameters}.
2594 The values you can use, to specify either of these pointer shapes, are
2595 defined in the file @file{lisp/term/x-win.el}. Use @kbd{M-x apropos
2596 @key{RET} x-pointer @key{RET}} to see a list of them.
2598 @node Window System Selections
2599 @section Window System Selections
2600 @cindex selection (for window systems)
2602 @cindex primary selection
2603 @cindex secondary selection
2605 In the X window system, data can be transferred between different
2606 applications by means of @dfn{selections}. X defines an arbitrary
2607 number of @dfn{selection types}, each of which can store its own data;
2608 however, only three are commonly used: the @dfn{clipboard},
2609 @dfn{primary selection}, and @dfn{secondary selection}. @xref{Cut and
2610 Paste,, Cut and Paste, emacs, The GNU Emacs Manual}, for Emacs
2611 commands that make use of these selections. This section documents
2612 the low-level functions for reading and setting X selections.
2614 @deffn Command x-set-selection type data
2615 This function sets an X selection. It takes two arguments: a
2616 selection type @var{type}, and the value to assign to it, @var{data}.
2618 @var{type} should be a symbol; it is usually one of @code{PRIMARY},
2619 @code{SECONDARY} or @code{CLIPBOARD}. These are symbols with
2620 upper-case names, in accord with X Window System conventions. If
2621 @var{type} is @code{nil}, that stands for @code{PRIMARY}.
2623 If @var{data} is @code{nil}, it means to clear out the selection.
2624 Otherwise, @var{data} may be a string, a symbol, an integer (or a cons
2625 of two integers or list of two integers), an overlay, or a cons of two
2626 markers pointing to the same buffer. An overlay or a pair of markers
2627 stands for text in the overlay or between the markers. The argument
2628 @var{data} may also be a vector of valid non-vector selection values.
2630 This function returns @var{data}.
2633 @defun x-get-selection &optional type data-type
2634 This function accesses selections set up by Emacs or by other X
2635 clients. It takes two optional arguments, @var{type} and
2636 @var{data-type}. The default for @var{type}, the selection type, is
2639 The @var{data-type} argument specifies the form of data conversion to
2640 use, to convert the raw data obtained from another X client into Lisp
2641 data. Meaningful values include @code{TEXT}, @code{STRING},
2642 @code{UTF8_STRING}, @code{TARGETS}, @code{LENGTH}, @code{DELETE},
2643 @code{FILE_NAME}, @code{CHARACTER_POSITION}, @code{NAME},
2644 @code{LINE_NUMBER}, @code{COLUMN_NUMBER}, @code{OWNER_OS},
2645 @code{HOST_NAME}, @code{USER}, @code{CLASS}, @code{ATOM}, and
2646 @code{INTEGER}. (These are symbols with upper-case names in accord
2647 with X conventions.) The default for @var{data-type} is
2651 @defopt selection-coding-system
2652 This variable specifies the coding system to use when reading and
2653 writing selections or the clipboard. @xref{Coding
2654 Systems}. The default is @code{compound-text-with-extensions}, which
2655 converts to the text representation that X11 normally uses.
2658 @cindex clipboard support (for MS-Windows)
2659 When Emacs runs on MS-Windows, it does not implement X selections in
2660 general, but it does support the clipboard. @code{x-get-selection}
2661 and @code{x-set-selection} on MS-Windows support the text data type
2662 only; if the clipboard holds other types of data, Emacs treats the
2666 @section Drag and Drop
2667 @cindex drag and drop
2669 @vindex x-dnd-test-function
2670 @vindex x-dnd-known-types
2671 When a user drags something from another application over Emacs, that other
2672 application expects Emacs to tell it if Emacs can handle the data that is
2673 dragged. The variable @code{x-dnd-test-function} is used by Emacs to determine
2674 what to reply. The default value is @code{x-dnd-default-test-function}
2675 which accepts drops if the type of the data to be dropped is present in
2676 @code{x-dnd-known-types}. You can customize @code{x-dnd-test-function} and/or
2677 @code{x-dnd-known-types} if you want Emacs to accept or reject drops based
2678 on some other criteria.
2680 @vindex x-dnd-types-alist
2681 If you want to change the way Emacs handles drop of different types
2682 or add a new type, customize @code{x-dnd-types-alist}. This requires
2683 detailed knowledge of what types other applications use for drag and
2686 @vindex dnd-protocol-alist
2687 When an URL is dropped on Emacs it may be a file, but it may also be
2688 another URL type (ftp, http, etc.). Emacs first checks
2689 @code{dnd-protocol-alist} to determine what to do with the URL@. If
2690 there is no match there and if @code{browse-url-browser-function} is
2691 an alist, Emacs looks for a match there. If no match is found the
2692 text for the URL is inserted. If you want to alter Emacs behavior,
2693 you can customize these variables.
2696 @section Color Names
2699 @cindex specify color
2700 @cindex numerical RGB color specification
2701 A color name is text (usually in a string) that specifies a color.
2702 Symbolic names such as @samp{black}, @samp{white}, @samp{red}, etc.,
2703 are allowed; use @kbd{M-x list-colors-display} to see a list of
2704 defined names. You can also specify colors numerically in forms such
2705 as @samp{#@var{rgb}} and @samp{RGB:@var{r}/@var{g}/@var{b}}, where
2706 @var{r} specifies the red level, @var{g} specifies the green level,
2707 and @var{b} specifies the blue level. You can use either one, two,
2708 three, or four hex digits for @var{r}; then you must use the same
2709 number of hex digits for all @var{g} and @var{b} as well, making
2710 either 3, 6, 9 or 12 hex digits in all. (See the documentation of the
2711 X Window System for more details about numerical RGB specification of
2714 These functions provide a way to determine which color names are
2715 valid, and what they look like. In some cases, the value depends on the
2716 @dfn{selected frame}, as described below; see @ref{Input Focus}, for the
2717 meaning of the term ``selected frame''.
2719 To read user input of color names with completion, use
2720 @code{read-color} (@pxref{High-Level Completion, read-color}).
2722 @defun color-defined-p color &optional frame
2723 This function reports whether a color name is meaningful. It returns
2724 @code{t} if so; otherwise, @code{nil}. The argument @var{frame} says
2725 which frame's display to ask about; if @var{frame} is omitted or
2726 @code{nil}, the selected frame is used.
2728 Note that this does not tell you whether the display you are using
2729 really supports that color. When using X, you can ask for any defined
2730 color on any kind of display, and you will get some result---typically,
2731 the closest it can do. To determine whether a frame can really display
2732 a certain color, use @code{color-supported-p} (see below).
2734 @findex x-color-defined-p
2735 This function used to be called @code{x-color-defined-p},
2736 and that name is still supported as an alias.
2739 @defun defined-colors &optional frame
2740 This function returns a list of the color names that are defined
2741 and supported on frame @var{frame} (default, the selected frame).
2742 If @var{frame} does not support colors, the value is @code{nil}.
2744 @findex x-defined-colors
2745 This function used to be called @code{x-defined-colors},
2746 and that name is still supported as an alias.
2749 @defun color-supported-p color &optional frame background-p
2750 This returns @code{t} if @var{frame} can really display the color
2751 @var{color} (or at least something close to it). If @var{frame} is
2752 omitted or @code{nil}, the question applies to the selected frame.
2754 Some terminals support a different set of colors for foreground and
2755 background. If @var{background-p} is non-@code{nil}, that means you are
2756 asking whether @var{color} can be used as a background; otherwise you
2757 are asking whether it can be used as a foreground.
2759 The argument @var{color} must be a valid color name.
2762 @defun color-gray-p color &optional frame
2763 This returns @code{t} if @var{color} is a shade of gray, as defined on
2764 @var{frame}'s display. If @var{frame} is omitted or @code{nil}, the
2765 question applies to the selected frame. If @var{color} is not a valid
2766 color name, this function returns @code{nil}.
2769 @defun color-values color &optional frame
2771 This function returns a value that describes what @var{color} should
2772 ideally look like on @var{frame}. If @var{color} is defined, the
2773 value is a list of three integers, which give the amount of red, the
2774 amount of green, and the amount of blue. Each integer ranges in
2775 principle from 0 to 65535, but some displays may not use the full
2776 range. This three-element list is called the @dfn{rgb values} of the
2779 If @var{color} is not defined, the value is @code{nil}.
2782 (color-values "black")
2784 (color-values "white")
2785 @result{} (65280 65280 65280)
2786 (color-values "red")
2787 @result{} (65280 0 0)
2788 (color-values "pink")
2789 @result{} (65280 49152 51968)
2790 (color-values "hungry")
2794 The color values are returned for @var{frame}'s display. If
2795 @var{frame} is omitted or @code{nil}, the information is returned for
2796 the selected frame's display. If the frame cannot display colors, the
2797 value is @code{nil}.
2799 @findex x-color-values
2800 This function used to be called @code{x-color-values},
2801 and that name is still supported as an alias.
2804 @node Text Terminal Colors
2805 @section Text Terminal Colors
2806 @cindex colors on text terminals
2808 Text terminals usually support only a small number of colors, and
2809 the computer uses small integers to select colors on the terminal.
2810 This means that the computer cannot reliably tell what the selected
2811 color looks like; instead, you have to inform your application which
2812 small integers correspond to which colors. However, Emacs does know
2813 the standard set of colors and will try to use them automatically.
2815 The functions described in this section control how terminal colors
2818 Several of these functions use or return @dfn{rgb values}, described
2819 in @ref{Color Names}.
2821 These functions accept a display (either a frame or the name of a
2822 terminal) as an optional argument. We hope in the future to make
2823 Emacs support different colors on different text terminals; then this
2824 argument will specify which terminal to operate on (the default being
2825 the selected frame's terminal; @pxref{Input Focus}). At present,
2826 though, the @var{frame} argument has no effect.
2828 @defun tty-color-define name number &optional rgb frame
2829 This function associates the color name @var{name} with
2830 color number @var{number} on the terminal.
2832 The optional argument @var{rgb}, if specified, is an rgb value, a list
2833 of three numbers that specify what the color actually looks like.
2834 If you do not specify @var{rgb}, then this color cannot be used by
2835 @code{tty-color-approximate} to approximate other colors, because
2836 Emacs will not know what it looks like.
2839 @defun tty-color-clear &optional frame
2840 This function clears the table of defined colors for a text terminal.
2843 @defun tty-color-alist &optional frame
2844 This function returns an alist recording the known colors supported by
2847 Each element has the form @code{(@var{name} @var{number} . @var{rgb})}
2848 or @code{(@var{name} @var{number})}. Here, @var{name} is the color
2849 name, @var{number} is the number used to specify it to the terminal.
2850 If present, @var{rgb} is a list of three color values (for red, green,
2851 and blue) that says what the color actually looks like.
2854 @defun tty-color-approximate rgb &optional frame
2855 This function finds the closest color, among the known colors
2856 supported for @var{display}, to that described by the rgb value
2857 @var{rgb} (a list of color values). The return value is an element of
2858 @code{tty-color-alist}.
2861 @defun tty-color-translate color &optional frame
2862 This function finds the closest color to @var{color} among the known
2863 colors supported for @var{display} and returns its index (an integer).
2864 If the name @var{color} is not defined, the value is @code{nil}.
2868 @section X Resources
2870 This section describes some of the functions and variables for
2871 querying and using X resources, or their equivalent on your operating
2872 system. @xref{X Resources,, X Resources, emacs, The GNU Emacs
2873 Manual}, for more information about X resources.
2875 @defun x-get-resource attribute class &optional component subclass
2876 The function @code{x-get-resource} retrieves a resource value from the X
2877 Window defaults database.
2879 Resources are indexed by a combination of a @dfn{key} and a @dfn{class}.
2880 This function searches using a key of the form
2881 @samp{@var{instance}.@var{attribute}} (where @var{instance} is the name
2882 under which Emacs was invoked), and using @samp{Emacs.@var{class}} as
2885 The optional arguments @var{component} and @var{subclass} add to the key
2886 and the class, respectively. You must specify both of them or neither.
2887 If you specify them, the key is
2888 @samp{@var{instance}.@var{component}.@var{attribute}}, and the class is
2889 @samp{Emacs.@var{class}.@var{subclass}}.
2892 @defvar x-resource-class
2893 This variable specifies the application name that @code{x-get-resource}
2894 should look up. The default value is @code{"Emacs"}. You can examine X
2895 resources for other application names by binding this
2896 variable to some other string, around a call to @code{x-get-resource}.
2899 @defvar x-resource-name
2900 This variable specifies the instance name that @code{x-get-resource}
2901 should look up. The default value is the name Emacs was invoked with,
2902 or the value specified with the @samp{-name} or @samp{-rn} switches.
2905 To illustrate some of the above, suppose that you have the line:
2908 xterm.vt100.background: yellow
2912 in your X resources file (whose name is usually @file{~/.Xdefaults}
2913 or @file{~/.Xresources}). Then:
2917 (let ((x-resource-class "XTerm") (x-resource-name "xterm"))
2918 (x-get-resource "vt100.background" "VT100.Background"))
2922 (let ((x-resource-class "XTerm") (x-resource-name "xterm"))
2923 (x-get-resource "background" "VT100" "vt100" "Background"))
2928 @defvar inhibit-x-resources
2929 If this variable is non-@code{nil}, Emacs does not look up X
2930 resources, and X resources do not have any effect when creating new
2934 @node Display Feature Testing
2935 @section Display Feature Testing
2936 @cindex display feature testing
2938 The functions in this section describe the basic capabilities of a
2939 particular display. Lisp programs can use them to adapt their behavior
2940 to what the display can do. For example, a program that ordinarily uses
2941 a popup menu could use the minibuffer if popup menus are not supported.
2943 The optional argument @var{display} in these functions specifies which
2944 display to ask the question about. It can be a display name, a frame
2945 (which designates the display that frame is on), or @code{nil} (which
2946 refers to the selected frame's display, @pxref{Input Focus}).
2948 @xref{Color Names}, @ref{Text Terminal Colors}, for other functions to
2949 obtain information about displays.
2951 @defun display-popup-menus-p &optional display
2952 This function returns @code{t} if popup menus are supported on
2953 @var{display}, @code{nil} if not. Support for popup menus requires
2954 that the mouse be available, since the menu is popped up by clicking
2955 the mouse on some portion of the Emacs display.
2958 @defun display-graphic-p &optional display
2959 This function returns @code{t} if @var{display} is a graphic display
2960 capable of displaying several frames and several different fonts at
2961 once. This is true for displays that use a window system such as X,
2962 and false for text terminals.
2965 @defun display-mouse-p &optional display
2966 @cindex mouse, availability
2967 This function returns @code{t} if @var{display} has a mouse available,
2971 @defun display-color-p &optional display
2972 @findex x-display-color-p
2973 This function returns @code{t} if the screen is a color screen.
2974 It used to be called @code{x-display-color-p}, and that name
2975 is still supported as an alias.
2978 @defun display-grayscale-p &optional display
2979 This function returns @code{t} if the screen can display shades of gray.
2980 (All color displays can do this.)
2983 @defun display-supports-face-attributes-p attributes &optional display
2984 @anchor{Display Face Attribute Testing}
2985 This function returns non-@code{nil} if all the face attributes in
2986 @var{attributes} are supported (@pxref{Face Attributes}).
2988 The definition of ``supported'' is somewhat heuristic, but basically
2989 means that a face containing all the attributes in @var{attributes},
2990 when merged with the default face for display, can be represented in a
2995 different in appearance than the default face, and
2998 close in spirit to what the attributes specify, if not exact.
3001 Point (2) implies that a @code{:weight black} attribute will be
3002 satisfied by any display that can display bold, as will
3003 @code{:foreground "yellow"} as long as some yellowish color can be
3004 displayed, but @code{:slant italic} will @emph{not} be satisfied by
3005 the tty display code's automatic substitution of a dim face for
3009 @defun display-selections-p &optional display
3010 This function returns @code{t} if @var{display} supports selections.
3011 Windowed displays normally support selections, but they may also be
3012 supported in some other cases.
3015 @defun display-images-p &optional display
3016 This function returns @code{t} if @var{display} can display images.
3017 Windowed displays ought in principle to handle images, but some
3018 systems lack the support for that. On a display that does not support
3019 images, Emacs cannot display a tool bar.
3022 @defun display-screens &optional display
3023 This function returns the number of screens associated with the display.
3026 @defun display-pixel-height &optional display
3027 This function returns the height of the screen in pixels.
3028 On a character terminal, it gives the height in characters.
3030 For graphical terminals, note that on multi-monitor setups this
3031 refers to the pixel height for all physical monitors associated with
3032 @var{display}. @xref{Multiple Terminals}.
3035 @defun display-pixel-width &optional display
3036 This function returns the width of the screen in pixels.
3037 On a character terminal, it gives the width in characters.
3039 For graphical terminals, note that on multi-monitor setups this
3040 refers to the pixel width for all physical monitors associated with
3041 @var{display}. @xref{Multiple Terminals}.
3044 @defun display-mm-height &optional display
3045 This function returns the height of the screen in millimeters,
3046 or @code{nil} if Emacs cannot get that information.
3048 For graphical terminals, note that on multi-monitor setups this
3049 refers to the height for all physical monitors associated with
3050 @var{display}. @xref{Multiple Terminals}.
3053 @defun display-mm-width &optional display
3054 This function returns the width of the screen in millimeters,
3055 or @code{nil} if Emacs cannot get that information.
3057 For graphical terminals, note that on multi-monitor setups this
3058 refers to the width for all physical monitors associated with
3059 @var{display}. @xref{Multiple Terminals}.
3062 @defopt display-mm-dimensions-alist
3063 This variable allows the user to specify the dimensions of graphical
3064 displays returned by @code{display-mm-height} and
3065 @code{display-mm-width} in case the system provides incorrect values.
3068 @cindex backing store
3069 @defun display-backing-store &optional display
3070 This function returns the backing store capability of the display.
3071 Backing store means recording the pixels of windows (and parts of
3072 windows) that are not exposed, so that when exposed they can be
3073 displayed very quickly.
3075 Values can be the symbols @code{always}, @code{when-mapped}, or
3076 @code{not-useful}. The function can also return @code{nil}
3077 when the question is inapplicable to a certain kind of display.
3080 @cindex SaveUnder feature
3081 @defun display-save-under &optional display
3082 This function returns non-@code{nil} if the display supports the
3083 SaveUnder feature. That feature is used by pop-up windows
3084 to save the pixels they obscure, so that they can pop down
3088 @defun display-planes &optional display
3089 This function returns the number of planes the display supports.
3090 This is typically the number of bits per pixel.
3091 For a tty display, it is log to base two of the number of colors supported.
3094 @defun display-visual-class &optional display
3095 This function returns the visual class for the screen. The value is
3096 one of the symbols @code{static-gray} (a limited, unchangeable number
3097 of grays), @code{gray-scale} (a full range of grays),
3098 @code{static-color} (a limited, unchangeable number of colors),
3099 @code{pseudo-color} (a limited number of colors), @code{true-color} (a
3100 full range of colors), and @code{direct-color} (a full range of
3104 @defun display-color-cells &optional display
3105 This function returns the number of color cells the screen supports.
3108 These functions obtain additional information about the window
3109 system in use where Emacs shows the specified @var{display}. (Their
3110 names begin with @code{x-} for historical reasons.)
3112 @defun x-server-version &optional display
3113 This function returns the list of version numbers of the GUI window
3114 system running on @var{display}, such as the X server on GNU and Unix
3115 systems. The value is a list of three integers: the major and minor
3116 version numbers of the protocol, and the distributor-specific release
3117 number of the window system software itself. On GNU and Unix systems,
3118 these are normally the version of the X protocol and the
3119 distributor-specific release number of the X server software. On
3120 MS-Windows, this is the version of the Windows OS.
3123 @defun x-server-vendor &optional display
3124 This function returns the vendor that provided the window system
3125 software (as a string). On GNU and Unix systems this really means
3126 whoever distributes the X server. On MS-Windows this is the vendor ID
3127 string of the Windows OS (Microsoft).
3129 When the developers of X labeled software distributors as
3130 ``vendors'', they showed their false assumption that no system could
3131 ever be developed and distributed noncommercially.
3135 @defvar x-no-window-manager
3136 This variable's value is @code{t} if no X window manager is in use.
3142 The functions @code{x-pixel-width} and @code{x-pixel-height} return the
3143 width and height of an X Window frame, measured in pixels.