Commit | Line | Data |
---|---|---|
b8d4c8d0 GM |
1 | @c -*-texinfo-*- |
2 | @c This is part of the GNU Emacs Lisp Reference Manual. | |
3 | @c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1998, 1999, 2001, | |
57ebf0be | 4 | @c 2002, 2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc. |
b8d4c8d0 | 5 | @c See the file elisp.texi for copying conditions. |
6336d8c3 | 6 | @setfilename ../../info/frames |
b8d4c8d0 GM |
7 | @node Frames, Positions, Windows, Top |
8 | @chapter Frames | |
9 | @cindex frame | |
10 | ||
11 | In Emacs editing, A @dfn{frame} is a screen object that contains one | |
12 | or more Emacs windows. It's the kind of object that is called a | |
13 | ``window'' in the terminology of graphical environments; but we can't | |
14 | call it a ``window'' here, because Emacs uses that word in a different | |
15 | way. | |
16 | ||
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. In Emacs Lisp, a @dfn{frame object} is a Lisp | |
20 | object that represents a frame on the screen. | |
21 | ||
22 | @cindex terminal frame | |
23 | When Emacs runs on a text-only terminal, it starts with one | |
24 | @dfn{terminal frame}. If you create additional ones, Emacs displays | |
25 | one and only one at any given time---on the terminal screen, of course. | |
26 | ||
27 | @cindex window frame | |
28 | When Emacs communicates directly with a supported window system, such | |
29 | as X, it does not have a terminal frame; instead, it starts with | |
30 | a single @dfn{window frame}, but you can create more, and Emacs can | |
31 | display several such frames at once as is usual for window systems. | |
32 | ||
33 | @defun framep object | |
34 | This predicate returns a non-@code{nil} value if @var{object} is a | |
35 | frame, and @code{nil} otherwise. For a frame, the value indicates which | |
36 | kind of display the frame uses: | |
37 | ||
38 | @table @code | |
39 | @item x | |
40 | The frame is displayed in an X window. | |
41 | @item t | |
42 | A terminal frame on a character display. | |
43 | @item mac | |
44 | The frame is displayed on a Macintosh. | |
45 | @item w32 | |
46 | The frame is displayed on MS-Windows 9X/NT. | |
47 | @item pc | |
48 | The frame is displayed on an MS-DOS terminal. | |
49 | @end table | |
50 | @end defun | |
51 | ||
52 | @menu | |
53 | * Creating Frames:: Creating additional frames. | |
54 | * Multiple Displays:: Creating frames on other displays. | |
55 | * Frame Parameters:: Controlling frame size, position, font, etc. | |
56 | * Frame Titles:: Automatic updating of frame titles. | |
57 | * Deleting Frames:: Frames last until explicitly deleted. | |
58 | * Finding All Frames:: How to examine all existing frames. | |
59 | * Frames and Windows:: A frame contains windows; | |
60 | display of text always works through windows. | |
61 | * Minibuffers and Frames:: How a frame finds the minibuffer to use. | |
62 | * Input Focus:: Specifying the selected frame. | |
63 | * Visibility of Frames:: Frames may be visible or invisible, or icons. | |
64 | * Raising and Lowering:: Raising a frame makes it hide other windows; | |
65 | lowering it makes the others hide it. | |
66 | * Frame Configurations:: Saving the state of all frames. | |
67 | * Mouse Tracking:: Getting events that say when the mouse moves. | |
68 | * Mouse Position:: Asking where the mouse is, or moving it. | |
69 | * Pop-Up Menus:: Displaying a menu for the user to select from. | |
70 | * Dialog Boxes:: Displaying a box to ask yes or no. | |
71 | * Pointer Shape:: Specifying the shape of the mouse pointer. | |
72 | * Window System Selections:: Transferring text to and from other X clients. | |
73 | * Drag and Drop:: Internals of Drag-and-Drop implementation. | |
74 | * Color Names:: Getting the definitions of color names. | |
75 | * Text Terminal Colors:: Defining colors for text-only terminals. | |
76 | * Resources:: Getting resource values from the server. | |
77 | * Display Feature Testing:: Determining the features of a terminal. | |
78 | @end menu | |
79 | ||
80 | @xref{Display}, for information about the related topic of | |
81 | controlling Emacs redisplay. | |
82 | ||
83 | @node Creating Frames | |
84 | @section Creating Frames | |
85 | ||
86 | To create a new frame, call the function @code{make-frame}. | |
87 | ||
88 | @defun make-frame &optional alist | |
89 | This function creates and returns a new frame, displaying the current | |
90 | buffer. If you are using a supported window system, it makes a window | |
91 | frame; otherwise, it makes a terminal frame. | |
92 | ||
93 | The argument is an alist specifying frame parameters. Any parameters | |
94 | not mentioned in @var{alist} default according to the value of the | |
95 | variable @code{default-frame-alist}; parameters not specified even there | |
96 | default from the standard X resources or whatever is used instead on | |
97 | your system. | |
98 | ||
99 | The set of possible parameters depends in principle on what kind of | |
100 | window system Emacs uses to display its frames. @xref{Window Frame | |
101 | Parameters}, for documentation of individual parameters you can specify. | |
102 | ||
103 | This function itself does not make the new frame the selected frame. | |
104 | @xref{Input Focus}. The previously selected frame remains selected. | |
105 | However, the window system may select the new frame for its own reasons, | |
106 | for instance if the frame appears under the mouse pointer and your | |
107 | setup is for focus to follow the pointer. | |
108 | @end defun | |
109 | ||
110 | @defvar before-make-frame-hook | |
111 | A normal hook run by @code{make-frame} before it actually creates the | |
112 | frame. | |
113 | @end defvar | |
114 | ||
115 | @defvar after-make-frame-functions | |
116 | An abnormal hook run by @code{make-frame} after it creates the frame. | |
117 | Each function in @code{after-make-frame-functions} receives one argument, the | |
118 | frame just created. | |
119 | @end defvar | |
120 | ||
121 | @node Multiple Displays | |
122 | @section Multiple Displays | |
123 | @cindex multiple X displays | |
124 | @cindex displays, multiple | |
125 | ||
126 | A single Emacs can talk to more than one X display. | |
127 | Initially, Emacs uses just one display---the one chosen with the | |
128 | @code{DISPLAY} environment variable or with the @samp{--display} option | |
129 | (@pxref{Initial Options,,, emacs, The GNU Emacs Manual}). To connect to | |
130 | another display, use the command @code{make-frame-on-display} or specify | |
131 | the @code{display} frame parameter when you create the frame. | |
132 | ||
133 | Emacs treats each X server as a separate terminal, giving each one its | |
134 | own selected frame and its own minibuffer windows. However, only one of | |
135 | those frames is ``@emph{the} selected frame'' at any given moment, see | |
136 | @ref{Input Focus}. | |
137 | ||
138 | A few Lisp variables are @dfn{terminal-local}; that is, they have a | |
139 | separate binding for each terminal. The binding in effect at any time | |
140 | is the one for the terminal that the currently selected frame belongs | |
141 | to. These variables include @code{default-minibuffer-frame}, | |
142 | @code{defining-kbd-macro}, @code{last-kbd-macro}, and | |
143 | @code{system-key-alist}. They are always terminal-local, and can never | |
56353e47 | 144 | be buffer-local (@pxref{Buffer-Local Variables}). |
b8d4c8d0 GM |
145 | |
146 | A single X server can handle more than one screen. A display name | |
147 | @samp{@var{host}:@var{server}.@var{screen}} has three parts; the last | |
148 | part specifies the screen number for a given server. When you use two | |
149 | screens belonging to one server, Emacs knows by the similarity in their | |
150 | names that they share a single keyboard, and it treats them as a single | |
151 | terminal. | |
152 | ||
153 | Note that some graphical terminals can output to more than a one | |
154 | monitor (or other output device) at the same time. On these | |
155 | ``multi-monitor'' setups, a single @var{display} value controls the | |
156 | output to all the physical monitors. In this situation, there is | |
157 | currently no platform-independent way for Emacs to distinguish between | |
158 | the different physical monitors. | |
159 | ||
160 | @deffn Command make-frame-on-display display &optional parameters | |
161 | This creates and returns a new frame on display @var{display}, taking | |
162 | the other frame parameters from @var{parameters}. Aside from the | |
163 | @var{display} argument, it is like @code{make-frame} (@pxref{Creating | |
164 | Frames}). | |
165 | @end deffn | |
166 | ||
167 | @defun x-display-list | |
168 | This returns a list that indicates which X displays Emacs has a | |
169 | connection to. The elements of the list are strings, and each one is | |
170 | a display name. | |
171 | @end defun | |
172 | ||
173 | @defun x-open-connection display &optional xrm-string must-succeed | |
174 | This function opens a connection to the X display @var{display}. It | |
175 | does not create a frame on that display, but it permits you to check | |
176 | that communication can be established with that display. | |
177 | ||
178 | The optional argument @var{xrm-string}, if not @code{nil}, is a | |
179 | string of resource names and values, in the same format used in the | |
180 | @file{.Xresources} file. The values you specify override the resource | |
181 | values recorded in the X server itself; they apply to all Emacs frames | |
182 | created on this display. Here's an example of what this string might | |
183 | look like: | |
184 | ||
185 | @example | |
186 | "*BorderWidth: 3\n*InternalBorder: 2\n" | |
187 | @end example | |
188 | ||
189 | @xref{X Resources,, X Resources, emacs, The GNU Emacs Manual}. | |
190 | ||
191 | If @var{must-succeed} is non-@code{nil}, failure to open the connection | |
192 | terminates Emacs. Otherwise, it is an ordinary Lisp error. | |
193 | @end defun | |
194 | ||
195 | @defun x-close-connection display | |
196 | This function closes the connection to display @var{display}. Before | |
197 | you can do this, you must first delete all the frames that were open on | |
198 | that display (@pxref{Deleting Frames}). | |
199 | @end defun | |
200 | ||
201 | @node Frame Parameters | |
202 | @section Frame Parameters | |
203 | @cindex frame parameters | |
204 | ||
205 | A frame has many parameters that control its appearance and behavior. | |
206 | Just what parameters a frame has depends on what display mechanism it | |
207 | uses. | |
208 | ||
209 | Frame parameters exist mostly for the sake of window systems. A | |
210 | terminal frame has a few parameters, mostly for compatibility's sake; | |
211 | only the @code{height}, @code{width}, @code{name}, @code{title}, | |
212 | @code{menu-bar-lines}, @code{buffer-list} and @code{buffer-predicate} | |
213 | parameters do something special. If the terminal supports colors, the | |
214 | parameters @code{foreground-color}, @code{background-color}, | |
215 | @code{background-mode} and @code{display-type} are also meaningful. | |
216 | ||
217 | @menu | |
218 | * Parameter Access:: How to change a frame's parameters. | |
219 | * Initial Parameters:: Specifying frame parameters when you make a frame. | |
220 | * Window Frame Parameters:: List of frame parameters for window systems. | |
221 | * Size and Position:: Changing the size and position of a frame. | |
222 | * Geometry:: Parsing geometry specifications. | |
223 | @end menu | |
224 | ||
225 | @node Parameter Access | |
226 | @subsection Access to Frame Parameters | |
227 | ||
228 | These functions let you read and change the parameter values of a | |
229 | frame. | |
230 | ||
231 | @defun frame-parameter frame parameter | |
232 | This function returns the value of the parameter @var{parameter} (a | |
233 | symbol) of @var{frame}. If @var{frame} is @code{nil}, it returns the | |
234 | selected frame's parameter. If @var{frame} has no setting for | |
235 | @var{parameter}, this function returns @code{nil}. | |
236 | @end defun | |
237 | ||
238 | @defun frame-parameters &optional frame | |
239 | The function @code{frame-parameters} returns an alist listing all the | |
240 | parameters of @var{frame} and their values. If @var{frame} is | |
241 | @code{nil} or omitted, this returns the selected frame's parameters | |
242 | @end defun | |
243 | ||
244 | @defun modify-frame-parameters frame alist | |
245 | This function alters the parameters of frame @var{frame} based on the | |
246 | elements of @var{alist}. Each element of @var{alist} has the form | |
247 | @code{(@var{parm} . @var{value})}, where @var{parm} is a symbol naming a | |
248 | parameter. If you don't mention a parameter in @var{alist}, its value | |
249 | doesn't change. If @var{frame} is @code{nil}, it defaults to the selected | |
250 | frame. | |
251 | @end defun | |
252 | ||
253 | @defun modify-all-frames-parameters alist | |
254 | This function alters the frame parameters of all existing frames | |
255 | according to @var{alist}, then modifies @code{default-frame-alist} | |
256 | (and, if necessary, @code{initial-frame-alist}) to apply the same | |
257 | parameter values to frames that will be created henceforth. | |
258 | @end defun | |
259 | ||
260 | @node Initial Parameters | |
261 | @subsection Initial Frame Parameters | |
262 | ||
263 | You can specify the parameters for the initial startup frame | |
264 | by setting @code{initial-frame-alist} in your init file (@pxref{Init File}). | |
265 | ||
266 | @defvar initial-frame-alist | |
267 | This variable's value is an alist of parameter values used when creating | |
268 | the initial window frame. You can set this variable to specify the | |
269 | appearance of the initial frame without altering subsequent frames. | |
270 | Each element has the form: | |
271 | ||
272 | @example | |
273 | (@var{parameter} . @var{value}) | |
274 | @end example | |
275 | ||
276 | Emacs creates the initial frame before it reads your init | |
277 | file. After reading that file, Emacs checks @code{initial-frame-alist}, | |
278 | and applies the parameter settings in the altered value to the already | |
279 | created initial frame. | |
280 | ||
281 | If these settings affect the frame geometry and appearance, you'll see | |
282 | the frame appear with the wrong ones and then change to the specified | |
283 | ones. If that bothers you, you can specify the same geometry and | |
284 | appearance with X resources; those do take effect before the frame is | |
285 | created. @xref{X Resources,, X Resources, emacs, The GNU Emacs Manual}. | |
286 | ||
287 | X resource settings typically apply to all frames. If you want to | |
288 | specify some X resources solely for the sake of the initial frame, and | |
289 | you don't want them to apply to subsequent frames, here's how to achieve | |
290 | this. Specify parameters in @code{default-frame-alist} to override the | |
291 | X resources for subsequent frames; then, to prevent these from affecting | |
292 | the initial frame, specify the same parameters in | |
293 | @code{initial-frame-alist} with values that match the X resources. | |
294 | @end defvar | |
295 | ||
296 | If these parameters specify a separate minibuffer-only frame with | |
297 | @code{(minibuffer . nil)}, and you have not created one, Emacs creates | |
298 | one for you. | |
299 | ||
300 | @defvar minibuffer-frame-alist | |
301 | This variable's value is an alist of parameter values used when creating | |
302 | an initial minibuffer-only frame---if such a frame is needed, according | |
303 | to the parameters for the main initial frame. | |
304 | @end defvar | |
305 | ||
306 | @defvar default-frame-alist | |
307 | This is an alist specifying default values of frame parameters for all | |
308 | Emacs frames---the first frame, and subsequent frames. When using the X | |
309 | Window System, you can get the same results by means of X resources | |
310 | in many cases. | |
311 | ||
312 | Setting this variable does not affect existing frames. | |
313 | @end defvar | |
314 | ||
315 | See also @code{special-display-frame-alist}. @xref{Definition of | |
316 | special-display-frame-alist}. | |
317 | ||
318 | If you use options that specify window appearance when you invoke Emacs, | |
319 | they take effect by adding elements to @code{default-frame-alist}. One | |
320 | exception is @samp{-geometry}, which adds the specified position to | |
321 | @code{initial-frame-alist} instead. @xref{Emacs Invocation,, Command | |
322 | Line Arguments for Emacs Invocation, emacs, The GNU Emacs Manual}. | |
323 | ||
324 | @node Window Frame Parameters | |
325 | @subsection Window Frame Parameters | |
326 | ||
327 | Just what parameters a frame has depends on what display mechanism | |
328 | it uses. This section describes the parameters that have special | |
329 | meanings on some or all kinds of terminals. Of these, @code{name}, | |
330 | @code{title}, @code{height}, @code{width}, @code{buffer-list} and | |
331 | @code{buffer-predicate} provide meaningful information in terminal | |
332 | frames, and @code{tty-color-mode} is meaningful @emph{only} in | |
333 | terminal frames. | |
334 | ||
335 | @menu | |
336 | * Basic Parameters:: Parameters that are fundamental. | |
337 | * Position Parameters:: The position of the frame on the screen. | |
338 | * Size Parameters:: Frame's size. | |
339 | * Layout Parameters:: Size of parts of the frame, and | |
340 | enabling or disabling some parts. | |
341 | * Buffer Parameters:: Which buffers have been or should be shown. | |
342 | * Management Parameters:: Communicating with the window manager. | |
343 | * Cursor Parameters:: Controlling the cursor appearance. | |
344 | * Color Parameters:: Colors of various parts of the frame. | |
345 | @end menu | |
346 | ||
347 | @node Basic Parameters | |
348 | @subsubsection Basic Parameters | |
349 | ||
350 | These frame parameters give the most basic information about the | |
351 | frame. @code{title} and @code{name} are meaningful on all terminals. | |
352 | ||
353 | @table @code | |
354 | @item display | |
355 | The display on which to open this frame. It should be a string of the | |
356 | form @code{"@var{host}:@var{dpy}.@var{screen}"}, just like the | |
357 | @code{DISPLAY} environment variable. | |
358 | ||
359 | @item display-type | |
360 | This parameter describes the range of possible colors that can be used | |
361 | in this frame. Its value is @code{color}, @code{grayscale} or | |
362 | @code{mono}. | |
363 | ||
364 | @item title | |
7f9e0c04 RS |
365 | If a frame has a non-@code{nil} title, it appears in the window |
366 | system's title bar at the top of the frame, and also in the mode line | |
367 | of windows in that frame if @code{mode-line-frame-identification} uses | |
368 | @samp{%F} (@pxref{%-Constructs}). This is normally the case when | |
369 | Emacs is not using a window system, and can only display one frame at | |
370 | a time. @xref{Frame Titles}. | |
b8d4c8d0 GM |
371 | |
372 | @item name | |
373 | The name of the frame. The frame name serves as a default for the frame | |
374 | title, if the @code{title} parameter is unspecified or @code{nil}. If | |
375 | you don't specify a name, Emacs sets the frame name automatically | |
376 | (@pxref{Frame Titles}). | |
377 | ||
378 | If you specify the frame name explicitly when you create the frame, the | |
379 | name is also used (instead of the name of the Emacs executable) when | |
380 | looking up X resources for the frame. | |
381 | ||
382 | @item display-environment-variable | |
383 | The value of the @code{DISPLAY} environment variable for the frame. It | |
384 | is passed to child processes. | |
385 | ||
386 | @item term-environment-variable | |
387 | The value of the @code{TERM} environment variable for the frame. It | |
388 | is passed to child processes. | |
389 | @end table | |
390 | ||
391 | @node Position Parameters | |
392 | @subsubsection Position Parameters | |
393 | ||
394 | Position parameters' values are normally measured in pixels, but on | |
395 | text-only terminals they count characters or lines instead. | |
396 | ||
397 | @table @code | |
398 | @item left | |
399 | The screen position of the left edge, in pixels, with respect to the | |
400 | left edge of the screen. The value may be a positive number @var{pos}, | |
401 | or a list of the form @code{(+ @var{pos})} which permits specifying a | |
402 | negative @var{pos} value. | |
403 | ||
404 | A negative number @minus{}@var{pos}, or a list of the form @code{(- | |
405 | @var{pos})}, actually specifies the position of the right edge of the | |
406 | window with respect to the right edge of the screen. A positive value | |
407 | of @var{pos} counts toward the left. @strong{Reminder:} if the | |
408 | parameter is a negative integer @minus{}@var{pos}, then @var{pos} is | |
409 | positive. | |
410 | ||
411 | Some window managers ignore program-specified positions. If you want to | |
412 | be sure the position you specify is not ignored, specify a | |
413 | non-@code{nil} value for the @code{user-position} parameter as well. | |
414 | ||
415 | @item top | |
416 | The screen position of the top edge, in pixels, with respect to the | |
417 | top edge of the screen. It works just like @code{left}, except vertically | |
418 | instead of horizontally. | |
419 | ||
420 | @item icon-left | |
421 | The screen position of the left edge @emph{of the frame's icon}, in | |
422 | pixels, counting from the left edge of the screen. This takes effect if | |
423 | and when the frame is iconified. | |
424 | ||
425 | If you specify a value for this parameter, then you must also specify | |
426 | a value for @code{icon-top} and vice versa. The window manager may | |
427 | ignore these two parameters. | |
428 | ||
429 | @item icon-top | |
430 | The screen position of the top edge @emph{of the frame's icon}, in | |
431 | pixels, counting from the top edge of the screen. This takes effect if | |
432 | and when the frame is iconified. | |
433 | ||
434 | @item user-position | |
435 | When you create a frame and specify its screen position with the | |
436 | @code{left} and @code{top} parameters, use this parameter to say whether | |
437 | the specified position was user-specified (explicitly requested in some | |
438 | way by a human user) or merely program-specified (chosen by a program). | |
439 | A non-@code{nil} value says the position was user-specified. | |
440 | ||
441 | Window managers generally heed user-specified positions, and some heed | |
442 | program-specified positions too. But many ignore program-specified | |
443 | positions, placing the window in a default fashion or letting the user | |
444 | place it with the mouse. Some window managers, including @code{twm}, | |
445 | let the user specify whether to obey program-specified positions or | |
446 | ignore them. | |
447 | ||
448 | When you call @code{make-frame}, you should specify a non-@code{nil} | |
449 | value for this parameter if the values of the @code{left} and @code{top} | |
450 | parameters represent the user's stated preference; otherwise, use | |
451 | @code{nil}. | |
452 | @end table | |
453 | ||
454 | @node Size Parameters | |
455 | @subsubsection Size Parameters | |
456 | ||
457 | Size parameters' values are normally measured in pixels, but on | |
458 | text-only terminals they count characters or lines instead. | |
459 | ||
460 | @table @code | |
461 | @item height | |
462 | The height of the frame contents, in characters. (To get the height in | |
463 | pixels, call @code{frame-pixel-height}; see @ref{Size and Position}.) | |
464 | ||
465 | @item width | |
101a6cea | 466 | The width of the frame contents, in characters. (To get the width in |
b8d4c8d0 GM |
467 | pixels, call @code{frame-pixel-width}; see @ref{Size and Position}.) |
468 | ||
469 | @item user-size | |
470 | This does for the size parameters @code{height} and @code{width} what | |
471 | the @code{user-position} parameter (see above) does for the position | |
472 | parameters @code{top} and @code{left}. | |
473 | ||
474 | @item fullscreen | |
475 | Specify that width, height or both shall be set to the size of the screen. | |
476 | The value @code{fullwidth} specifies that width shall be the size of the | |
477 | screen. The value @code{fullheight} specifies that height shall be the | |
478 | size of the screen. The value @code{fullboth} specifies that both the | |
479 | width and the height shall be set to the size of the screen. | |
480 | @end table | |
481 | ||
482 | @node Layout Parameters | |
483 | @subsubsection Layout Parameters | |
484 | ||
485 | These frame parameters enable or disable various parts of the | |
486 | frame, or control their sizes. | |
487 | ||
488 | @table @code | |
489 | @item border-width | |
490 | The width in pixels of the frame's border. | |
491 | ||
492 | @item internal-border-width | |
493 | The distance in pixels between text (or fringe) and the frame's border. | |
494 | ||
495 | @item vertical-scroll-bars | |
496 | Whether the frame has scroll bars for vertical scrolling, and which side | |
497 | of the frame they should be on. The possible values are @code{left}, | |
498 | @code{right}, and @code{nil} for no scroll bars. | |
499 | ||
500 | @ignore | |
501 | @item horizontal-scroll-bars | |
502 | Whether the frame has scroll bars for horizontal scrolling | |
503 | (non-@code{nil} means yes). Horizontal scroll bars are not currently | |
504 | implemented. | |
505 | @end ignore | |
506 | ||
507 | @item scroll-bar-width | |
508 | The width of vertical scroll bars, in pixels, or @code{nil} meaning to | |
509 | use the default width. | |
510 | ||
511 | @item left-fringe | |
512 | @itemx right-fringe | |
513 | The default width of the left and right fringes of windows in this | |
514 | frame (@pxref{Fringes}). If either of these is zero, that effectively | |
515 | removes the corresponding fringe. A value of @code{nil} stands for | |
516 | the standard fringe width, which is the width needed to display the | |
517 | fringe bitmaps. | |
518 | ||
519 | The combined fringe widths must add up to an integral number of | |
520 | columns, so the actual default fringe widths for the frame may be | |
521 | larger than the specified values. The extra width needed to reach an | |
522 | acceptable total is distributed evenly between the left and right | |
523 | fringe. However, you can force one fringe or the other to a precise | |
524 | width by specifying that width as a negative integer. If both widths are | |
525 | negative, only the left fringe gets the specified width. | |
526 | ||
527 | @item menu-bar-lines | |
528 | The number of lines to allocate at the top of the frame for a menu | |
529 | bar. The default is 1. A value of @code{nil} means don't display a | |
530 | menu bar. @xref{Menu Bar}. (The X toolkit and GTK allow at most one | |
531 | menu bar line; they treat larger values as 1.) | |
532 | ||
533 | @item tool-bar-lines | |
534 | The number of lines to use for the tool bar. A value of @code{nil} | |
535 | means don't display a tool bar. (GTK allows at most one tool bar line; | |
536 | it treats larger values as 1.) | |
537 | ||
538 | @item line-spacing | |
539 | Additional space to leave below each text line, in pixels (a positive | |
540 | integer). @xref{Line Height}, for more information. | |
541 | @end table | |
542 | ||
543 | @node Buffer Parameters | |
544 | @subsubsection Buffer Parameters | |
545 | ||
546 | These frame parameters, meaningful on all kinds of terminals, deal | |
547 | with which buffers have been, or should, be displayed in the frame. | |
548 | ||
549 | @table @code | |
550 | @item minibuffer | |
551 | Whether this frame has its own minibuffer. The value @code{t} means | |
552 | yes, @code{nil} means no, @code{only} means this frame is just a | |
553 | minibuffer. If the value is a minibuffer window (in some other frame), | |
554 | the new frame uses that minibuffer. | |
555 | ||
556 | @item buffer-predicate | |
557 | The buffer-predicate function for this frame. The function | |
558 | @code{other-buffer} uses this predicate (from the selected frame) to | |
559 | decide which buffers it should consider, if the predicate is not | |
560 | @code{nil}. It calls the predicate with one argument, a buffer, once for | |
561 | each buffer; if the predicate returns a non-@code{nil} value, it | |
562 | considers that buffer. | |
563 | ||
564 | @item buffer-list | |
565 | A list of buffers that have been selected in this frame, | |
566 | ordered most-recently-selected first. | |
567 | ||
568 | @item unsplittable | |
569 | If non-@code{nil}, this frame's window is never split automatically. | |
570 | @end table | |
571 | ||
572 | @node Management Parameters | |
573 | @subsubsection Window Management Parameters | |
574 | @cindex window manager, and frame parameters | |
575 | ||
576 | These frame parameters, meaningful only on window system displays, | |
577 | interact with the window manager. | |
578 | ||
579 | @table @code | |
580 | @item visibility | |
581 | The state of visibility of the frame. There are three possibilities: | |
582 | @code{nil} for invisible, @code{t} for visible, and @code{icon} for | |
583 | iconified. @xref{Visibility of Frames}. | |
584 | ||
585 | @item auto-raise | |
586 | Whether selecting the frame raises it (non-@code{nil} means yes). | |
587 | ||
588 | @item auto-lower | |
589 | Whether deselecting the frame lowers it (non-@code{nil} means yes). | |
590 | ||
591 | @item icon-type | |
592 | The type of icon to use for this frame when it is iconified. If the | |
593 | value is a string, that specifies a file containing a bitmap to use. | |
594 | Any other non-@code{nil} value specifies the default bitmap icon (a | |
595 | picture of a gnu); @code{nil} specifies a text icon. | |
596 | ||
597 | @item icon-name | |
598 | The name to use in the icon for this frame, when and if the icon | |
599 | appears. If this is @code{nil}, the frame's title is used. | |
600 | ||
601 | @item window-id | |
602 | The number of the window-system window used by the frame | |
603 | to contain the actual Emacs windows. | |
604 | ||
605 | @item outer-window-id | |
606 | The number of the outermost window-system window used for the whole frame. | |
607 | ||
608 | @item wait-for-wm | |
609 | If non-@code{nil}, tell Xt to wait for the window manager to confirm | |
610 | geometry changes. Some window managers, including versions of Fvwm2 | |
611 | and KDE, fail to confirm, so Xt hangs. Set this to @code{nil} to | |
612 | prevent hanging with those window managers. | |
613 | ||
614 | @ignore | |
615 | @item parent-id | |
616 | @c ??? Not yet working. | |
617 | The X window number of the window that should be the parent of this one. | |
618 | Specifying this lets you create an Emacs window inside some other | |
619 | application's window. (It is not certain this will be implemented; try | |
620 | it and see if it works.) | |
621 | @end ignore | |
622 | @end table | |
623 | ||
624 | @node Cursor Parameters | |
625 | @subsubsection Cursor Parameters | |
626 | ||
627 | This frame parameter controls the way the cursor looks. | |
628 | ||
629 | @table @code | |
630 | @item cursor-type | |
631 | How to display the cursor. Legitimate values are: | |
632 | ||
633 | @table @code | |
634 | @item box | |
635 | Display a filled box. (This is the default.) | |
636 | @item hollow | |
637 | Display a hollow box. | |
638 | @item nil | |
639 | Don't display a cursor. | |
640 | @item bar | |
641 | Display a vertical bar between characters. | |
642 | @item (bar . @var{width}) | |
643 | Display a vertical bar @var{width} pixels wide between characters. | |
644 | @item hbar | |
645 | Display a horizontal bar. | |
646 | @item (hbar . @var{height}) | |
647 | Display a horizontal bar @var{height} pixels high. | |
648 | @end table | |
649 | @end table | |
650 | ||
651 | @vindex cursor-type | |
652 | The buffer-local variable @code{cursor-type} overrides the value of | |
653 | the @code{cursor-type} frame parameter, but if it is @code{t}, that | |
654 | means to use the cursor specified for the frame. | |
655 | ||
656 | @defvar blink-cursor-alist | |
657 | This variable specifies how to blink the cursor. Each element has the | |
658 | form @code{(@var{on-state} . @var{off-state})}. Whenever the cursor | |
659 | type equals @var{on-state} (comparing using @code{equal}), the | |
660 | corresponding @var{off-state} specifies what the cursor looks like | |
661 | when it blinks ``off.'' Both @var{on-state} and @var{off-state} | |
662 | should be suitable values for the @code{cursor-type} frame parameter. | |
663 | ||
664 | There are various defaults for how to blink each type of cursor, if | |
665 | the type is not mentioned as an @var{on-state} here. Changes in this | |
36c763fd RS |
666 | variable do not take effect immediately, only when you specify the |
667 | @code{cursor-type} frame parameter. | |
668 | @end defvar | |
669 | ||
670 | @defvar cursor-in-non-selected-windows | |
671 | This variable controls how the cursor looks in a window that is not | |
672 | selected. It supports the same values as the @code{cursor-type} frame | |
673 | parameter; also, @code{nil} means don't display a cursor in | |
674 | nonselected windows, and @code{t} (the default) means use a standard | |
675 | modificatoin of the usual cursor type (solid box becomes hollow box, | |
676 | and bar becomes a narrower bar). | |
b8d4c8d0 GM |
677 | @end defvar |
678 | ||
679 | @node Color Parameters | |
680 | @subsubsection Color Parameters | |
681 | ||
682 | These frame parameters control the use of colors. | |
683 | ||
684 | @table @code | |
685 | @item background-mode | |
686 | This parameter is either @code{dark} or @code{light}, according | |
687 | to whether the background color is a light one or a dark one. | |
688 | ||
689 | @item tty-color-mode | |
690 | @cindex standard colors for character terminals | |
691 | This parameter overrides the terminal's color support as given by the | |
692 | system's terminal capabilities database in that this parameter's value | |
693 | specifies the color mode to use in terminal frames. The value can be | |
694 | either a symbol or a number. A number specifies the number of colors | |
695 | to use (and, indirectly, what commands to issue to produce each | |
696 | color). For example, @code{(tty-color-mode . 8)} specifies use of the | |
697 | ANSI escape sequences for 8 standard text colors. A value of -1 turns | |
698 | off color support. | |
699 | ||
700 | If the parameter's value is a symbol, it specifies a number through | |
701 | the value of @code{tty-color-mode-alist}, and the associated number is | |
702 | used instead. | |
703 | ||
704 | @item screen-gamma | |
705 | @cindex gamma correction | |
706 | If this is a number, Emacs performs ``gamma correction'' which adjusts | |
707 | the brightness of all colors. The value should be the screen gamma of | |
708 | your display, a floating point number. | |
709 | ||
710 | Usual PC monitors have a screen gamma of 2.2, so color values in | |
711 | Emacs, and in X windows generally, are calibrated to display properly | |
712 | on a monitor with that gamma value. If you specify 2.2 for | |
713 | @code{screen-gamma}, that means no correction is needed. Other values | |
714 | request correction, designed to make the corrected colors appear on | |
715 | your screen the way they would have appeared without correction on an | |
716 | ordinary monitor with a gamma value of 2.2. | |
717 | ||
718 | If your monitor displays colors too light, you should specify a | |
719 | @code{screen-gamma} value smaller than 2.2. This requests correction | |
720 | that makes colors darker. A screen gamma value of 1.5 may give good | |
721 | results for LCD color displays. | |
722 | @end table | |
723 | ||
724 | These frame parameters are semi-obsolete in that they are automatically | |
725 | equivalent to particular face attributes of particular faces. | |
726 | @xref{Standard Faces,,, emacs, The Emacs Manual}. | |
727 | ||
728 | @table @code | |
729 | @item font | |
730 | The name of the font for displaying text in the frame. This is a | |
731 | string, either a valid font name for your system or the name of an Emacs | |
732 | fontset (@pxref{Fontsets}). It is equivalent to the @code{font} | |
733 | attribute of the @code{default} face. | |
734 | ||
735 | @item foreground-color | |
736 | The color to use for the image of a character. It is equivalent to | |
737 | the @code{:foreground} attribute of the @code{default} face. | |
738 | ||
739 | @item background-color | |
740 | The color to use for the background of characters. It is equivalent to | |
741 | the @code{:background} attribute of the @code{default} face. | |
742 | ||
743 | @item mouse-color | |
744 | The color for the mouse pointer. It is equivalent to the @code{:background} | |
745 | attribute of the @code{mouse} face. | |
746 | ||
747 | @item cursor-color | |
748 | The color for the cursor that shows point. It is equivalent to the | |
749 | @code{:background} attribute of the @code{cursor} face. | |
750 | ||
751 | @item border-color | |
752 | The color for the border of the frame. It is equivalent to the | |
753 | @code{:background} attribute of the @code{border} face. | |
754 | ||
755 | @item scroll-bar-foreground | |
756 | If non-@code{nil}, the color for the foreground of scroll bars. It is | |
757 | equivalent to the @code{:foreground} attribute of the | |
758 | @code{scroll-bar} face. | |
759 | ||
760 | @item scroll-bar-background | |
761 | If non-@code{nil}, the color for the background of scroll bars. It is | |
762 | equivalent to the @code{:background} attribute of the | |
763 | @code{scroll-bar} face. | |
764 | @end table | |
765 | ||
766 | @node Size and Position | |
767 | @subsection Frame Size And Position | |
768 | @cindex size of frame | |
769 | @cindex screen size | |
770 | @cindex frame size | |
771 | @cindex resize frame | |
772 | ||
773 | You can read or change the size and position of a frame using the | |
774 | frame parameters @code{left}, @code{top}, @code{height}, and | |
775 | @code{width}. Whatever geometry parameters you don't specify are chosen | |
776 | by the window manager in its usual fashion. | |
777 | ||
778 | Here are some special features for working with sizes and positions. | |
779 | (For the precise meaning of ``selected frame'' used by these functions, | |
780 | see @ref{Input Focus}.) | |
781 | ||
782 | @defun set-frame-position frame left top | |
783 | This function sets the position of the top left corner of @var{frame} to | |
784 | @var{left} and @var{top}. These arguments are measured in pixels, and | |
785 | normally count from the top left corner of the screen. | |
786 | ||
787 | Negative parameter values position the bottom edge of the window up from | |
788 | the bottom edge of the screen, or the right window edge to the left of | |
789 | the right edge of the screen. It would probably be better if the values | |
790 | were always counted from the left and top, so that negative arguments | |
791 | would position the frame partly off the top or left edge of the screen, | |
792 | but it seems inadvisable to change that now. | |
793 | @end defun | |
794 | ||
795 | @defun frame-height &optional frame | |
796 | @defunx frame-width &optional frame | |
797 | These functions return the height and width of @var{frame}, measured in | |
798 | lines and columns. If you don't supply @var{frame}, they use the | |
799 | selected frame. | |
800 | @end defun | |
801 | ||
802 | @defun screen-height | |
803 | @defunx screen-width | |
804 | These functions are old aliases for @code{frame-height} and | |
805 | @code{frame-width}. When you are using a non-window terminal, the size | |
806 | of the frame is normally the same as the size of the terminal screen. | |
807 | @end defun | |
808 | ||
809 | @defun frame-pixel-height &optional frame | |
810 | @defunx frame-pixel-width &optional frame | |
041817a4 RS |
811 | These functions return the height and width of the main display area |
812 | of @var{frame}, measured in pixels. If you don't supply @var{frame}, | |
813 | they use the selected frame. | |
814 | ||
815 | These values include the internal borders, and windows' scroll bars | |
816 | and fringes (which belong to individual windows, not to the frame | |
817 | itself), but do not include menu bars or tool bars (except when using | |
818 | X without an X toolkit). | |
b8d4c8d0 GM |
819 | @end defun |
820 | ||
821 | @defun frame-char-height &optional frame | |
822 | @defunx frame-char-width &optional frame | |
823 | These functions return the height and width of a character in | |
824 | @var{frame}, measured in pixels. The values depend on the choice of | |
825 | font. If you don't supply @var{frame}, these functions use the selected | |
826 | frame. | |
827 | @end defun | |
828 | ||
829 | @defun set-frame-size frame cols rows | |
830 | This function sets the size of @var{frame}, measured in characters; | |
831 | @var{cols} and @var{rows} specify the new width and height. | |
832 | ||
833 | To set the size based on values measured in pixels, use | |
834 | @code{frame-char-height} and @code{frame-char-width} to convert | |
835 | them to units of characters. | |
836 | @end defun | |
837 | ||
838 | @defun set-frame-height frame lines &optional pretend | |
839 | This function resizes @var{frame} to a height of @var{lines} lines. The | |
840 | sizes of existing windows in @var{frame} are altered proportionally to | |
841 | fit. | |
842 | ||
843 | If @var{pretend} is non-@code{nil}, then Emacs displays @var{lines} | |
844 | lines of output in @var{frame}, but does not change its value for the | |
845 | actual height of the frame. This is only useful for a terminal frame. | |
846 | Using a smaller height than the terminal actually implements may be | |
847 | useful to reproduce behavior observed on a smaller screen, or if the | |
848 | terminal malfunctions when using its whole screen. Setting the frame | |
849 | height ``for real'' does not always work, because knowing the correct | |
850 | actual size may be necessary for correct cursor positioning on a | |
851 | terminal frame. | |
852 | @end defun | |
853 | ||
854 | @defun set-frame-width frame width &optional pretend | |
855 | This function sets the width of @var{frame}, measured in characters. | |
856 | The argument @var{pretend} has the same meaning as in | |
857 | @code{set-frame-height}. | |
858 | @end defun | |
859 | ||
860 | @findex set-screen-height | |
861 | @findex set-screen-width | |
862 | The older functions @code{set-screen-height} and | |
863 | @code{set-screen-width} were used to specify the height and width of the | |
864 | screen, in Emacs versions that did not support multiple frames. They | |
865 | are semi-obsolete, but still work; they apply to the selected frame. | |
866 | ||
867 | @node Geometry | |
868 | @subsection Geometry | |
869 | ||
870 | Here's how to examine the data in an X-style window geometry | |
871 | specification: | |
872 | ||
873 | @defun x-parse-geometry geom | |
874 | @cindex geometry specification | |
875 | The function @code{x-parse-geometry} converts a standard X window | |
876 | geometry string to an alist that you can use as part of the argument to | |
877 | @code{make-frame}. | |
878 | ||
879 | The alist describes which parameters were specified in @var{geom}, and | |
880 | gives the values specified for them. Each element looks like | |
881 | @code{(@var{parameter} . @var{value})}. The possible @var{parameter} | |
882 | values are @code{left}, @code{top}, @code{width}, and @code{height}. | |
883 | ||
884 | For the size parameters, the value must be an integer. The position | |
885 | parameter names @code{left} and @code{top} are not totally accurate, | |
886 | because some values indicate the position of the right or bottom edges | |
887 | instead. These are the @var{value} possibilities for the position | |
888 | parameters: | |
889 | ||
890 | @table @asis | |
891 | @item an integer | |
892 | A positive integer relates the left edge or top edge of the window to | |
893 | the left or top edge of the screen. A negative integer relates the | |
894 | right or bottom edge of the window to the right or bottom edge of the | |
895 | screen. | |
896 | ||
897 | @item @code{(+ @var{position})} | |
898 | This specifies the position of the left or top edge of the window | |
899 | relative to the left or top edge of the screen. The integer | |
900 | @var{position} may be positive or negative; a negative value specifies a | |
901 | position outside the screen. | |
902 | ||
903 | @item @code{(- @var{position})} | |
904 | This specifies the position of the right or bottom edge of the window | |
905 | relative to the right or bottom edge of the screen. The integer | |
906 | @var{position} may be positive or negative; a negative value specifies a | |
907 | position outside the screen. | |
908 | @end table | |
909 | ||
910 | Here is an example: | |
911 | ||
912 | @example | |
913 | (x-parse-geometry "35x70+0-0") | |
914 | @result{} ((height . 70) (width . 35) | |
915 | (top - 0) (left . 0)) | |
916 | @end example | |
917 | @end defun | |
918 | ||
919 | @node Frame Titles | |
920 | @section Frame Titles | |
921 | @cindex frame title | |
922 | ||
923 | Every frame has a @code{name} parameter; this serves as the default | |
924 | for the frame title which window systems typically display at the top of | |
925 | the frame. You can specify a name explicitly by setting the @code{name} | |
926 | frame property. | |
927 | ||
928 | Normally you don't specify the name explicitly, and Emacs computes the | |
929 | frame name automatically based on a template stored in the variable | |
930 | @code{frame-title-format}. Emacs recomputes the name each time the | |
931 | frame is redisplayed. | |
932 | ||
933 | @defvar frame-title-format | |
934 | This variable specifies how to compute a name for a frame when you have | |
935 | not explicitly specified one. The variable's value is actually a mode | |
936 | line construct, just like @code{mode-line-format}, except that the | |
937 | @samp{%c} and @samp{%l} constructs are ignored. @xref{Mode Line | |
938 | Data}. | |
939 | @end defvar | |
940 | ||
941 | @defvar icon-title-format | |
942 | This variable specifies how to compute the name for an iconified frame, | |
943 | when you have not explicitly specified the frame title. This title | |
944 | appears in the icon itself. | |
945 | @end defvar | |
946 | ||
947 | @defvar multiple-frames | |
948 | This variable is set automatically by Emacs. Its value is @code{t} when | |
949 | there are two or more frames (not counting minibuffer-only frames or | |
950 | invisible frames). The default value of @code{frame-title-format} uses | |
951 | @code{multiple-frames} so as to put the buffer name in the frame title | |
952 | only when there is more than one frame. | |
953 | ||
954 | The value of this variable is not guaranteed to be accurate except | |
955 | while processing @code{frame-title-format} or | |
956 | @code{icon-title-format}. | |
957 | @end defvar | |
958 | ||
959 | @node Deleting Frames | |
960 | @section Deleting Frames | |
961 | @cindex deleting frames | |
962 | ||
963 | Frames remain potentially visible until you explicitly @dfn{delete} | |
964 | them. A deleted frame cannot appear on the screen, but continues to | |
965 | exist as a Lisp object until there are no references to it. | |
966 | ||
967 | @deffn Command delete-frame &optional frame force | |
968 | @vindex delete-frame-functions | |
969 | This function deletes the frame @var{frame}. Unless @var{frame} is a | |
970 | tooltip, it first runs the hook @code{delete-frame-functions} (each | |
971 | function gets one argument, @var{frame}). By default, @var{frame} is | |
972 | the selected frame. | |
973 | ||
974 | A frame cannot be deleted if its minibuffer is used by other frames. | |
975 | Normally, you cannot delete a frame if all other frames are invisible, | |
976 | but if the @var{force} is non-@code{nil}, then you are allowed to do so. | |
977 | @end deffn | |
978 | ||
979 | @defun frame-live-p frame | |
980 | The function @code{frame-live-p} returns non-@code{nil} if the frame | |
981 | @var{frame} has not been deleted. The possible non-@code{nil} return | |
982 | values are like those of @code{framep}. @xref{Frames}. | |
983 | @end defun | |
984 | ||
985 | Some window managers provide a command to delete a window. These work | |
986 | by sending a special message to the program that operates the window. | |
987 | When Emacs gets one of these commands, it generates a | |
988 | @code{delete-frame} event, whose normal definition is a command that | |
989 | calls the function @code{delete-frame}. @xref{Misc Events}. | |
990 | ||
991 | @node Finding All Frames | |
992 | @section Finding All Frames | |
993 | @cindex frames, scanning all | |
994 | ||
995 | @defun frame-list | |
996 | The function @code{frame-list} returns a list of all the frames that | |
997 | have not been deleted. It is analogous to @code{buffer-list} for | |
998 | buffers, and includes frames on all terminals. The list that you get is | |
999 | newly created, so modifying the list doesn't have any effect on the | |
1000 | internals of Emacs. | |
1001 | @end defun | |
1002 | ||
1003 | @defun visible-frame-list | |
1004 | This function returns a list of just the currently visible frames. | |
1005 | @xref{Visibility of Frames}. (Terminal frames always count as | |
1006 | ``visible,'' even though only the selected one is actually displayed.) | |
1007 | @end defun | |
1008 | ||
1009 | @defun next-frame &optional frame minibuf | |
1010 | The function @code{next-frame} lets you cycle conveniently through all | |
1011 | the frames on the current display from an arbitrary starting point. It | |
1012 | returns the ``next'' frame after @var{frame} in the cycle. If | |
1013 | @var{frame} is omitted or @code{nil}, it defaults to the selected frame | |
1014 | (@pxref{Input Focus}). | |
1015 | ||
1016 | The second argument, @var{minibuf}, says which frames to consider: | |
1017 | ||
1018 | @table @asis | |
1019 | @item @code{nil} | |
1020 | Exclude minibuffer-only frames. | |
1021 | @item @code{visible} | |
1022 | Consider all visible frames. | |
1023 | @item 0 | |
1024 | Consider all visible or iconified frames. | |
1025 | @item a window | |
1026 | Consider only the frames using that particular window as their | |
1027 | minibuffer. | |
1028 | @item anything else | |
1029 | Consider all frames. | |
1030 | @end table | |
1031 | @end defun | |
1032 | ||
1033 | @defun previous-frame &optional frame minibuf | |
1034 | Like @code{next-frame}, but cycles through all frames in the opposite | |
1035 | direction. | |
1036 | @end defun | |
1037 | ||
1038 | See also @code{next-window} and @code{previous-window}, in @ref{Cyclic | |
1039 | Window Ordering}. | |
1040 | ||
1041 | @node Frames and Windows | |
1042 | @section Frames and Windows | |
1043 | ||
1044 | Each window is part of one and only one frame; you can get the frame | |
1045 | with @code{window-frame}. | |
1046 | ||
1047 | @defun window-frame window | |
1048 | This function returns the frame that @var{window} is on. | |
1049 | @end defun | |
1050 | ||
1051 | All the non-minibuffer windows in a frame are arranged in a cyclic | |
1052 | order. The order runs from the frame's top window, which is at the | |
1053 | upper left corner, down and to the right, until it reaches the window at | |
1054 | the lower right corner (always the minibuffer window, if the frame has | |
1055 | one), and then it moves back to the top. @xref{Cyclic Window Ordering}. | |
1056 | ||
1057 | @defun frame-first-window &optional frame | |
1058 | This returns the topmost, leftmost window of frame @var{frame}. | |
1059 | If omitted or @code{nil}, @var{frame} defaults to the selected frame. | |
1060 | @end defun | |
1061 | ||
1062 | At any time, exactly one window on any frame is @dfn{selected within the | |
1063 | frame}. The significance of this designation is that selecting the | |
1064 | frame also selects this window. You can get the frame's current | |
1065 | selected window with @code{frame-selected-window}. | |
1066 | ||
1067 | @defun frame-selected-window &optional frame | |
1068 | This function returns the window on @var{frame} that is selected | |
1069 | within @var{frame}. If omitted or @code{nil}, @var{frame} defaults to | |
1070 | the selected frame. | |
1071 | @end defun | |
1072 | ||
1073 | @defun set-frame-selected-window frame window | |
1074 | This sets the selected window of frame @var{frame} to @var{window}. | |
1075 | If @var{frame} is @code{nil}, it operates on the selected frame. If | |
1076 | @var{frame} is the selected frame, this makes @var{window} the | |
1077 | selected window. This function returns @var{window}. | |
1078 | @end defun | |
1079 | ||
1080 | Conversely, selecting a window for Emacs with @code{select-window} also | |
1081 | makes that window selected within its frame. @xref{Selecting Windows}. | |
1082 | ||
1083 | Another function that (usually) returns one of the windows in a given | |
1084 | frame is @code{minibuffer-window}. @xref{Definition of minibuffer-window}. | |
1085 | ||
1086 | @node Minibuffers and Frames | |
1087 | @section Minibuffers and Frames | |
1088 | ||
1089 | Normally, each frame has its own minibuffer window at the bottom, which | |
1090 | is used whenever that frame is selected. If the frame has a minibuffer, | |
1091 | you can get it with @code{minibuffer-window} (@pxref{Definition of | |
1092 | minibuffer-window}). | |
1093 | ||
1094 | However, you can also create a frame with no minibuffer. Such a frame | |
1095 | must use the minibuffer window of some other frame. When you create the | |
1096 | frame, you can specify explicitly the minibuffer window to use (in some | |
1097 | other frame). If you don't, then the minibuffer is found in the frame | |
1098 | which is the value of the variable @code{default-minibuffer-frame}. Its | |
1099 | value should be a frame that does have a minibuffer. | |
1100 | ||
1101 | If you use a minibuffer-only frame, you might want that frame to raise | |
1102 | when you enter the minibuffer. If so, set the variable | |
1103 | @code{minibuffer-auto-raise} to @code{t}. @xref{Raising and Lowering}. | |
1104 | ||
1105 | @defvar default-minibuffer-frame | |
1106 | This variable specifies the frame to use for the minibuffer window, by | |
1107 | default. It does not affect existing frames. It is always local to | |
1108 | the current terminal and cannot be buffer-local. @xref{Multiple | |
1109 | Displays}. | |
1110 | @end defvar | |
1111 | ||
1112 | @node Input Focus | |
1113 | @section Input Focus | |
1114 | @cindex input focus | |
1115 | @c @cindex selected frame Duplicates selected-frame | |
1116 | ||
1117 | At any time, one frame in Emacs is the @dfn{selected frame}. The selected | |
1118 | window always resides on the selected frame. | |
1119 | ||
1120 | When Emacs displays its frames on several terminals (@pxref{Multiple | |
1121 | Displays}), each terminal has its own selected frame. But only one of | |
1122 | these is ``@emph{the} selected frame'': it's the frame that belongs to | |
1123 | the terminal from which the most recent input came. That is, when Emacs | |
1124 | runs a command that came from a certain terminal, the selected frame is | |
1125 | the one of that terminal. Since Emacs runs only a single command at any | |
1126 | given time, it needs to consider only one selected frame at a time; this | |
1127 | frame is what we call @dfn{the selected frame} in this manual. The | |
1128 | display on which the selected frame is displayed is the @dfn{selected | |
1129 | frame's display}. | |
1130 | ||
1131 | @defun selected-frame | |
1132 | This function returns the selected frame. | |
1133 | @end defun | |
1134 | ||
1135 | Some window systems and window managers direct keyboard input to the | |
1136 | window object that the mouse is in; others require explicit clicks or | |
1137 | commands to @dfn{shift the focus} to various window objects. Either | |
1138 | way, Emacs automatically keeps track of which frame has the focus. To | |
1139 | switch to a different frame from a Lisp function, call | |
1140 | @code{select-frame-set-input-focus}. | |
1141 | ||
1142 | Lisp programs can also switch frames ``temporarily'' by calling the | |
1143 | function @code{select-frame}. This does not alter the window system's | |
1144 | concept of focus; rather, it escapes from the window manager's control | |
1145 | until that control is somehow reasserted. | |
1146 | ||
1147 | When using a text-only terminal, only one frame can be displayed at a | |
1148 | time on the terminal, so after a call to @code{select-frame}, the next | |
1149 | redisplay actually displays the newly selected frame. This frame | |
1150 | remains selected until a subsequent call to @code{select-frame} or | |
1151 | @code{select-frame-set-input-focus}. Each terminal frame has a number | |
1152 | which appears in the mode line before the buffer name (@pxref{Mode | |
1153 | Line Variables}). | |
1154 | ||
1155 | @defun select-frame-set-input-focus frame | |
1156 | This function makes @var{frame} the selected frame, raises it (should | |
1157 | it happen to be obscured by other frames) and tries to give it the X | |
1158 | server's focus. On a text-only terminal, the next redisplay displays | |
1159 | the new frame on the entire terminal screen. The return value of this | |
1160 | function is not significant. | |
1161 | @end defun | |
1162 | ||
1163 | @c ??? This is not yet implemented properly. | |
1164 | @defun select-frame frame | |
1165 | This function selects frame @var{frame}, temporarily disregarding the | |
1166 | focus of the X server if any. The selection of @var{frame} lasts until | |
1167 | the next time the user does something to select a different frame, or | |
1168 | until the next time this function is called. (If you are using a | |
1169 | window system, the previously selected frame may be restored as the | |
1170 | selected frame after return to the command loop, because it still may | |
1171 | have the window system's input focus.) The specified @var{frame} | |
1172 | becomes the selected frame, as explained above, and the terminal that | |
1173 | @var{frame} is on becomes the selected terminal. This function | |
1174 | returns @var{frame}, or @code{nil} if @var{frame} has been deleted. | |
1175 | ||
1176 | In general, you should never use @code{select-frame} in a way that could | |
1177 | switch to a different terminal without switching back when you're done. | |
1178 | @end defun | |
1179 | ||
1180 | Emacs cooperates with the window system by arranging to select frames as | |
1181 | the server and window manager request. It does so by generating a | |
1182 | special kind of input event, called a @dfn{focus} event, when | |
1183 | appropriate. The command loop handles a focus event by calling | |
1184 | @code{handle-switch-frame}. @xref{Focus Events}. | |
1185 | ||
1186 | @deffn Command handle-switch-frame frame | |
1187 | This function handles a focus event by selecting frame @var{frame}. | |
1188 | ||
1189 | Focus events normally do their job by invoking this command. | |
1190 | Don't call it for any other reason. | |
1191 | @end deffn | |
1192 | ||
1193 | @defun redirect-frame-focus frame &optional focus-frame | |
1194 | This function redirects focus from @var{frame} to @var{focus-frame}. | |
1195 | This means that @var{focus-frame} will receive subsequent keystrokes and | |
1196 | events intended for @var{frame}. After such an event, the value of | |
1197 | @code{last-event-frame} will be @var{focus-frame}. Also, switch-frame | |
1198 | events specifying @var{frame} will instead select @var{focus-frame}. | |
1199 | ||
1200 | If @var{focus-frame} is omitted or @code{nil}, that cancels any existing | |
1201 | redirection for @var{frame}, which therefore once again receives its own | |
1202 | events. | |
1203 | ||
1204 | One use of focus redirection is for frames that don't have minibuffers. | |
1205 | These frames use minibuffers on other frames. Activating a minibuffer | |
1206 | on another frame redirects focus to that frame. This puts the focus on | |
1207 | the minibuffer's frame, where it belongs, even though the mouse remains | |
1208 | in the frame that activated the minibuffer. | |
1209 | ||
1210 | Selecting a frame can also change focus redirections. Selecting frame | |
1211 | @code{bar}, when @code{foo} had been selected, changes any redirections | |
1212 | pointing to @code{foo} so that they point to @code{bar} instead. This | |
1213 | allows focus redirection to work properly when the user switches from | |
1214 | one frame to another using @code{select-window}. | |
1215 | ||
1216 | This means that a frame whose focus is redirected to itself is treated | |
1217 | differently from a frame whose focus is not redirected. | |
1218 | @code{select-frame} affects the former but not the latter. | |
1219 | ||
1220 | The redirection lasts until @code{redirect-frame-focus} is called to | |
1221 | change it. | |
1222 | @end defun | |
1223 | ||
1224 | @defopt focus-follows-mouse | |
1225 | This option is how you inform Emacs whether the window manager transfers | |
1226 | focus when the user moves the mouse. Non-@code{nil} says that it does. | |
1227 | When this is so, the command @code{other-frame} moves the mouse to a | |
1228 | position consistent with the new selected frame. (This option has no | |
1229 | effect on MS-Windows, where the mouse pointer is always automatically | |
1230 | moved by the OS to the selected frame.) | |
1231 | @end defopt | |
1232 | ||
1233 | @node Visibility of Frames | |
1234 | @section Visibility of Frames | |
1235 | @cindex visible frame | |
1236 | @cindex invisible frame | |
1237 | @cindex iconified frame | |
1238 | @cindex frame visibility | |
1239 | ||
1240 | A window frame may be @dfn{visible}, @dfn{invisible}, or | |
1241 | @dfn{iconified}. If it is visible, you can see its contents, unless | |
1242 | other windows cover it. If it is iconified, the frame's contents do | |
1243 | not appear on the screen, but an icon does. If the frame is | |
1244 | invisible, it doesn't show on the screen, not even as an icon. | |
1245 | ||
1246 | Visibility is meaningless for terminal frames, since only the selected | |
1247 | one is actually displayed in any case. | |
1248 | ||
1249 | @deffn Command make-frame-visible &optional frame | |
1250 | This function makes frame @var{frame} visible. If you omit | |
1251 | @var{frame}, it makes the selected frame visible. This does not raise | |
1252 | the frame, but you can do that with @code{raise-frame} if you wish | |
1253 | (@pxref{Raising and Lowering}). | |
1254 | @end deffn | |
1255 | ||
1256 | @deffn Command make-frame-invisible &optional frame force | |
1257 | This function makes frame @var{frame} invisible. If you omit | |
1258 | @var{frame}, it makes the selected frame invisible. | |
1259 | ||
1260 | Unless @var{force} is non-@code{nil}, this function refuses to make | |
1261 | @var{frame} invisible if all other frames are invisible.. | |
1262 | @end deffn | |
1263 | ||
1264 | @deffn Command iconify-frame &optional frame | |
1265 | This function iconifies frame @var{frame}. If you omit @var{frame}, it | |
1266 | iconifies the selected frame. | |
1267 | @end deffn | |
1268 | ||
1269 | @defun frame-visible-p frame | |
1270 | This returns the visibility status of frame @var{frame}. The value is | |
1271 | @code{t} if @var{frame} is visible, @code{nil} if it is invisible, and | |
1272 | @code{icon} if it is iconified. | |
1273 | ||
1274 | On a text-only terminal, all frames are considered visible, whether | |
1275 | they are currently being displayed or not, and this function returns | |
1276 | @code{t} for all frames. | |
1277 | @end defun | |
1278 | ||
1279 | The visibility status of a frame is also available as a frame | |
1280 | parameter. You can read or change it as such. @xref{Management | |
1281 | Parameters}. | |
1282 | ||
1283 | The user can iconify and deiconify frames with the window manager. | |
1284 | This happens below the level at which Emacs can exert any control, but | |
1285 | Emacs does provide events that you can use to keep track of such | |
1286 | changes. @xref{Misc Events}. | |
1287 | ||
1288 | @node Raising and Lowering | |
1289 | @section Raising and Lowering Frames | |
1290 | ||
1291 | Most window systems use a desktop metaphor. Part of this metaphor is | |
1292 | the idea that windows are stacked in a notional third dimension | |
1293 | perpendicular to the screen surface, and thus ordered from ``highest'' | |
1294 | to ``lowest.'' Where two windows overlap, the one higher up covers | |
1295 | the one underneath. Even a window at the bottom of the stack can be | |
1296 | seen if no other window overlaps it. | |
1297 | ||
1298 | @c @cindex raising a frame redundant with raise-frame | |
1299 | @cindex lowering a frame | |
1300 | A window's place in this ordering is not fixed; in fact, users tend | |
1301 | to change the order frequently. @dfn{Raising} a window means moving | |
1302 | it ``up,'' to the top of the stack. @dfn{Lowering} a window means | |
1303 | moving it to the bottom of the stack. This motion is in the notional | |
1304 | third dimension only, and does not change the position of the window | |
1305 | on the screen. | |
1306 | ||
1307 | You can raise and lower Emacs frame Windows with these functions: | |
1308 | ||
1309 | @deffn Command raise-frame &optional frame | |
1310 | This function raises frame @var{frame} (default, the selected frame). | |
1311 | If @var{frame} is invisible or iconified, this makes it visible. | |
1312 | @end deffn | |
1313 | ||
1314 | @deffn Command lower-frame &optional frame | |
1315 | This function lowers frame @var{frame} (default, the selected frame). | |
1316 | @end deffn | |
1317 | ||
1318 | @defopt minibuffer-auto-raise | |
1319 | If this is non-@code{nil}, activation of the minibuffer raises the frame | |
1320 | that the minibuffer window is in. | |
1321 | @end defopt | |
1322 | ||
1323 | You can also enable auto-raise (raising automatically when a frame is | |
1324 | selected) or auto-lower (lowering automatically when it is deselected) | |
1325 | for any frame using frame parameters. @xref{Management Parameters}. | |
1326 | ||
1327 | @node Frame Configurations | |
1328 | @section Frame Configurations | |
1329 | @cindex frame configuration | |
1330 | ||
1331 | A @dfn{frame configuration} records the current arrangement of frames, | |
1332 | all their properties, and the window configuration of each one. | |
1333 | (@xref{Window Configurations}.) | |
1334 | ||
1335 | @defun current-frame-configuration | |
1336 | This function returns a frame configuration list that describes | |
1337 | the current arrangement of frames and their contents. | |
1338 | @end defun | |
1339 | ||
1340 | @defun set-frame-configuration configuration &optional nodelete | |
1341 | This function restores the state of frames described in | |
1342 | @var{configuration}. However, this function does not restore deleted | |
1343 | frames. | |
1344 | ||
1345 | Ordinarily, this function deletes all existing frames not listed in | |
1346 | @var{configuration}. But if @var{nodelete} is non-@code{nil}, the | |
1347 | unwanted frames are iconified instead. | |
1348 | @end defun | |
1349 | ||
1350 | @node Mouse Tracking | |
1351 | @section Mouse Tracking | |
1352 | @cindex mouse tracking | |
1353 | @c @cindex tracking the mouse Duplicates track-mouse | |
1354 | ||
1355 | Sometimes it is useful to @dfn{track} the mouse, which means to display | |
1356 | something to indicate where the mouse is and move the indicator as the | |
1357 | mouse moves. For efficient mouse tracking, you need a way to wait until | |
1358 | the mouse actually moves. | |
1359 | ||
1360 | The convenient way to track the mouse is to ask for events to represent | |
1361 | mouse motion. Then you can wait for motion by waiting for an event. In | |
1362 | addition, you can easily handle any other sorts of events that may | |
1363 | occur. That is useful, because normally you don't want to track the | |
1364 | mouse forever---only until some other event, such as the release of a | |
1365 | button. | |
1366 | ||
1367 | @defspec track-mouse body@dots{} | |
1368 | This special form executes @var{body}, with generation of mouse motion | |
1369 | events enabled. Typically @var{body} would use @code{read-event} to | |
1370 | read the motion events and modify the display accordingly. @xref{Motion | |
1371 | Events}, for the format of mouse motion events. | |
1372 | ||
1373 | The value of @code{track-mouse} is that of the last form in @var{body}. | |
1374 | You should design @var{body} to return when it sees the up-event that | |
1375 | indicates the release of the button, or whatever kind of event means | |
1376 | it is time to stop tracking. | |
1377 | @end defspec | |
1378 | ||
1379 | The usual purpose of tracking mouse motion is to indicate on the screen | |
1380 | the consequences of pushing or releasing a button at the current | |
1381 | position. | |
1382 | ||
1383 | In many cases, you can avoid the need to track the mouse by using | |
1384 | the @code{mouse-face} text property (@pxref{Special Properties}). | |
1385 | That works at a much lower level and runs more smoothly than | |
1386 | Lisp-level mouse tracking. | |
1387 | ||
1388 | @ignore | |
1389 | @c These are not implemented yet. | |
1390 | ||
1391 | These functions change the screen appearance instantaneously. The | |
1392 | effect is transient, only until the next ordinary Emacs redisplay. That | |
1393 | is OK for mouse tracking, since it doesn't make sense for mouse tracking | |
1394 | to change the text, and the body of @code{track-mouse} normally reads | |
1395 | the events itself and does not do redisplay. | |
1396 | ||
1397 | @defun x-contour-region window beg end | |
1398 | This function draws lines to make a box around the text from @var{beg} | |
1399 | to @var{end}, in window @var{window}. | |
1400 | @end defun | |
1401 | ||
1402 | @defun x-uncontour-region window beg end | |
1403 | This function erases the lines that would make a box around the text | |
1404 | from @var{beg} to @var{end}, in window @var{window}. Use it to remove | |
1405 | a contour that you previously made by calling @code{x-contour-region}. | |
1406 | @end defun | |
1407 | ||
1408 | @defun x-draw-rectangle frame left top right bottom | |
1409 | This function draws a hollow rectangle on frame @var{frame} with the | |
1410 | specified edge coordinates, all measured in pixels from the inside top | |
1411 | left corner. It uses the cursor color, the one used for indicating the | |
1412 | location of point. | |
1413 | @end defun | |
1414 | ||
1415 | @defun x-erase-rectangle frame left top right bottom | |
1416 | This function erases a hollow rectangle on frame @var{frame} with the | |
1417 | specified edge coordinates, all measured in pixels from the inside top | |
1418 | left corner. Erasure means redrawing the text and background that | |
1419 | normally belong in the specified rectangle. | |
1420 | @end defun | |
1421 | @end ignore | |
1422 | ||
1423 | @node Mouse Position | |
1424 | @section Mouse Position | |
1425 | @cindex mouse position | |
1426 | @cindex position of mouse | |
1427 | ||
1428 | The functions @code{mouse-position} and @code{set-mouse-position} | |
1429 | give access to the current position of the mouse. | |
1430 | ||
1431 | @defun mouse-position | |
1432 | This function returns a description of the position of the mouse. The | |
1433 | value looks like @code{(@var{frame} @var{x} . @var{y})}, where @var{x} | |
1434 | and @var{y} are integers giving the position in characters relative to | |
1435 | the top left corner of the inside of @var{frame}. | |
1436 | @end defun | |
1437 | ||
1438 | @defvar mouse-position-function | |
1439 | If non-@code{nil}, the value of this variable is a function for | |
1440 | @code{mouse-position} to call. @code{mouse-position} calls this | |
1441 | function just before returning, with its normal return value as the | |
1442 | sole argument, and it returns whatever this function returns to it. | |
1443 | ||
1444 | This abnormal hook exists for the benefit of packages like | |
1445 | @file{xt-mouse.el} that need to do mouse handling at the Lisp level. | |
1446 | @end defvar | |
1447 | ||
1448 | @defun set-mouse-position frame x y | |
1449 | This function @dfn{warps the mouse} to position @var{x}, @var{y} in | |
1450 | frame @var{frame}. The arguments @var{x} and @var{y} are integers, | |
1451 | giving the position in characters relative to the top left corner of the | |
1452 | inside of @var{frame}. If @var{frame} is not visible, this function | |
1453 | does nothing. The return value is not significant. | |
1454 | @end defun | |
1455 | ||
1456 | @defun mouse-pixel-position | |
1457 | This function is like @code{mouse-position} except that it returns | |
1458 | coordinates in units of pixels rather than units of characters. | |
1459 | @end defun | |
1460 | ||
1461 | @defun set-mouse-pixel-position frame x y | |
1462 | This function warps the mouse like @code{set-mouse-position} except that | |
1463 | @var{x} and @var{y} are in units of pixels rather than units of | |
1464 | characters. These coordinates are not required to be within the frame. | |
1465 | ||
1466 | If @var{frame} is not visible, this function does nothing. The return | |
1467 | value is not significant. | |
1468 | @end defun | |
1469 | ||
1470 | @need 3000 | |
1471 | ||
1472 | @node Pop-Up Menus | |
1473 | @section Pop-Up Menus | |
1474 | ||
1475 | When using a window system, a Lisp program can pop up a menu so that | |
1476 | the user can choose an alternative with the mouse. | |
1477 | ||
1478 | @defun x-popup-menu position menu | |
1479 | This function displays a pop-up menu and returns an indication of | |
1480 | what selection the user makes. | |
1481 | ||
1482 | The argument @var{position} specifies where on the screen to put the | |
1483 | top left corner of the menu. It can be either a mouse button event | |
1484 | (which says to put the menu where the user actuated the button) or a | |
1485 | list of this form: | |
1486 | ||
1487 | @example | |
1488 | ((@var{xoffset} @var{yoffset}) @var{window}) | |
1489 | @end example | |
1490 | ||
1491 | @noindent | |
1492 | where @var{xoffset} and @var{yoffset} are coordinates, measured in | |
1493 | pixels, counting from the top left corner of @var{window}. @var{window} | |
1494 | may be a window or a frame. | |
1495 | ||
1496 | If @var{position} is @code{t}, it means to use the current mouse | |
1497 | position. If @var{position} is @code{nil}, it means to precompute the | |
1498 | key binding equivalents for the keymaps specified in @var{menu}, | |
1499 | without actually displaying or popping up the menu. | |
1500 | ||
1501 | The argument @var{menu} says what to display in the menu. It can be a | |
1502 | keymap or a list of keymaps (@pxref{Menu Keymaps}). In this case, the | |
1503 | return value is the list of events corresponding to the user's choice. | |
1504 | (This list has more than one element if the choice occurred in a | |
1505 | submenu.) Note that @code{x-popup-menu} does not actually execute the | |
1506 | command bound to that sequence of events. | |
1507 | ||
1508 | Alternatively, @var{menu} can have the following form: | |
1509 | ||
1510 | @example | |
1511 | (@var{title} @var{pane1} @var{pane2}...) | |
1512 | @end example | |
1513 | ||
1514 | @noindent | |
1515 | where each pane is a list of form | |
1516 | ||
1517 | @example | |
1518 | (@var{title} @var{item1} @var{item2}...) | |
1519 | @end example | |
1520 | ||
1521 | Each item should normally be a cons cell @code{(@var{line} . @var{value})}, | |
1522 | where @var{line} is a string, and @var{value} is the value to return if | |
1523 | that @var{line} is chosen. An item can also be a string; this makes a | |
1524 | non-selectable line in the menu. | |
1525 | ||
1526 | If the user gets rid of the menu without making a valid choice, for | |
1527 | instance by clicking the mouse away from a valid choice or by typing | |
1528 | keyboard input, then this normally results in a quit and | |
1529 | @code{x-popup-menu} does not return. But if @var{position} is a mouse | |
1530 | button event (indicating that the user invoked the menu with the | |
1531 | mouse) then no quit occurs and @code{x-popup-menu} returns @code{nil}. | |
1532 | @end defun | |
1533 | ||
1534 | @strong{Usage note:} Don't use @code{x-popup-menu} to display a menu | |
1535 | if you could do the job with a prefix key defined with a menu keymap. | |
1536 | If you use a menu keymap to implement a menu, @kbd{C-h c} and @kbd{C-h | |
1537 | a} can see the individual items in that menu and provide help for them. | |
1538 | If instead you implement the menu by defining a command that calls | |
1539 | @code{x-popup-menu}, the help facilities cannot know what happens inside | |
1540 | that command, so they cannot give any help for the menu's items. | |
1541 | ||
1542 | The menu bar mechanism, which lets you switch between submenus by | |
1543 | moving the mouse, cannot look within the definition of a command to see | |
1544 | that it calls @code{x-popup-menu}. Therefore, if you try to implement a | |
1545 | submenu using @code{x-popup-menu}, it cannot work with the menu bar in | |
1546 | an integrated fashion. This is why all menu bar submenus are | |
1547 | implemented with menu keymaps within the parent menu, and never with | |
1548 | @code{x-popup-menu}. @xref{Menu Bar}. | |
1549 | ||
1550 | If you want a menu bar submenu to have contents that vary, you should | |
1551 | still use a menu keymap to implement it. To make the contents vary, add | |
1552 | a hook function to @code{menu-bar-update-hook} to update the contents of | |
1553 | the menu keymap as necessary. | |
1554 | ||
1555 | @node Dialog Boxes | |
1556 | @section Dialog Boxes | |
1557 | @cindex dialog boxes | |
1558 | ||
1559 | A dialog box is a variant of a pop-up menu---it looks a little | |
1560 | different, it always appears in the center of a frame, and it has just | |
1561 | one level and one or more buttons. The main use of dialog boxes is | |
1562 | for asking questions that the user can answer with ``yes,'' ``no,'' | |
1563 | and a few other alternatives. With a single button, they can also | |
1564 | force the user to acknowledge important information. The functions | |
1565 | @code{y-or-n-p} and @code{yes-or-no-p} use dialog boxes instead of the | |
1566 | keyboard, when called from commands invoked by mouse clicks. | |
1567 | ||
1568 | @defun x-popup-dialog position contents &optional header | |
1569 | This function displays a pop-up dialog box and returns an indication of | |
1570 | what selection the user makes. The argument @var{contents} specifies | |
1571 | the alternatives to offer; it has this format: | |
1572 | ||
1573 | @example | |
1574 | (@var{title} (@var{string} . @var{value})@dots{}) | |
1575 | @end example | |
1576 | ||
1577 | @noindent | |
1578 | which looks like the list that specifies a single pane for | |
1579 | @code{x-popup-menu}. | |
1580 | ||
1581 | The return value is @var{value} from the chosen alternative. | |
1582 | ||
1583 | As for @code{x-popup-menu}, an element of the list may be just a | |
1584 | string instead of a cons cell @code{(@var{string} . @var{value})}. | |
1585 | That makes a box that cannot be selected. | |
1586 | ||
1587 | If @code{nil} appears in the list, it separates the left-hand items from | |
1588 | the right-hand items; items that precede the @code{nil} appear on the | |
1589 | left, and items that follow the @code{nil} appear on the right. If you | |
1590 | don't include a @code{nil} in the list, then approximately half the | |
1591 | items appear on each side. | |
1592 | ||
1593 | Dialog boxes always appear in the center of a frame; the argument | |
1594 | @var{position} specifies which frame. The possible values are as in | |
1595 | @code{x-popup-menu}, but the precise coordinates or the individual | |
1596 | window don't matter; only the frame matters. | |
1597 | ||
1598 | If @var{header} is non-@code{nil}, the frame title for the box is | |
1599 | @samp{Information}, otherwise it is @samp{Question}. The former is used | |
1600 | for @code{message-box} (@pxref{message-box}). | |
1601 | ||
1602 | In some configurations, Emacs cannot display a real dialog box; so | |
1603 | instead it displays the same items in a pop-up menu in the center of the | |
1604 | frame. | |
1605 | ||
1606 | If the user gets rid of the dialog box without making a valid choice, | |
1607 | for instance using the window manager, then this produces a quit and | |
1608 | @code{x-popup-dialog} does not return. | |
1609 | @end defun | |
1610 | ||
1611 | @node Pointer Shape | |
1612 | @section Pointer Shape | |
1613 | @cindex pointer shape | |
1614 | @cindex mouse pointer shape | |
1615 | ||
1616 | You can specify the mouse pointer style for particular text or | |
1617 | images using the @code{pointer} text property, and for images with the | |
1618 | @code{:pointer} and @code{:map} image properties. The values you can | |
1619 | use in these properties are @code{text} (or @code{nil}), @code{arrow}, | |
1620 | @code{hand}, @code{vdrag}, @code{hdrag}, @code{modeline}, and | |
1621 | @code{hourglass}. @code{text} stands for the usual mouse pointer | |
1622 | style used over text. | |
1623 | ||
1624 | Over void parts of the window (parts that do not correspond to any | |
1625 | of the buffer contents), the mouse pointer usually uses the | |
1626 | @code{arrow} style, but you can specify a different style (one of | |
1627 | those above) by setting @code{void-text-area-pointer}. | |
1628 | ||
1629 | @defvar void-text-area-pointer | |
1630 | This variable specifies the mouse pointer style for void text areas. | |
1631 | These include the areas after the end of a line or below the last line | |
1632 | in the buffer. The default is to use the @code{arrow} (non-text) | |
1633 | pointer style. | |
1634 | @end defvar | |
1635 | ||
1636 | You can specify what the @code{text} pointer style really looks like | |
1637 | by setting the variable @code{x-pointer-shape}. | |
1638 | ||
1639 | @defvar x-pointer-shape | |
1640 | This variable specifies the pointer shape to use ordinarily in the | |
1641 | Emacs frame, for the @code{text} pointer style. | |
1642 | @end defvar | |
1643 | ||
1644 | @defvar x-sensitive-text-pointer-shape | |
1645 | This variable specifies the pointer shape to use when the mouse | |
1646 | is over mouse-sensitive text. | |
1647 | @end defvar | |
1648 | ||
1649 | These variables affect newly created frames. They do not normally | |
1650 | affect existing frames; however, if you set the mouse color of a | |
1651 | frame, that also installs the current value of those two variables. | |
1652 | @xref{Color Parameters}. | |
1653 | ||
1654 | The values you can use, to specify either of these pointer shapes, are | |
1655 | defined in the file @file{lisp/term/x-win.el}. Use @kbd{M-x apropos | |
1656 | @key{RET} x-pointer @key{RET}} to see a list of them. | |
1657 | ||
1658 | @node Window System Selections | |
1659 | @section Window System Selections | |
1660 | @cindex selection (for window systems) | |
1661 | ||
1662 | The X server records a set of @dfn{selections} which permit transfer of | |
1663 | data between application programs. The various selections are | |
1664 | distinguished by @dfn{selection types}, represented in Emacs by | |
1665 | symbols. X clients including Emacs can read or set the selection for | |
1666 | any given type. | |
1667 | ||
1668 | @deffn Command x-set-selection type data | |
1669 | This function sets a ``selection'' in the X server. It takes two | |
1670 | arguments: a selection type @var{type}, and the value to assign to it, | |
1671 | @var{data}. If @var{data} is @code{nil}, it means to clear out the | |
1672 | selection. Otherwise, @var{data} may be a string, a symbol, an integer | |
1673 | (or a cons of two integers or list of two integers), an overlay, or a | |
1674 | cons of two markers pointing to the same buffer. An overlay or a pair | |
1675 | of markers stands for text in the overlay or between the markers. | |
1676 | ||
1677 | The argument @var{data} may also be a vector of valid non-vector | |
1678 | selection values. | |
1679 | ||
1680 | Each possible @var{type} has its own selection value, which changes | |
1681 | independently. The usual values of @var{type} are @code{PRIMARY}, | |
1682 | @code{SECONDARY} and @code{CLIPBOARD}; these are symbols with upper-case | |
1683 | names, in accord with X Window System conventions. If @var{type} is | |
1684 | @code{nil}, that stands for @code{PRIMARY}. | |
1685 | ||
1686 | This function returns @var{data}. | |
1687 | @end deffn | |
1688 | ||
1689 | @defun x-get-selection &optional type data-type | |
1690 | This function accesses selections set up by Emacs or by other X | |
1691 | clients. It takes two optional arguments, @var{type} and | |
1692 | @var{data-type}. The default for @var{type}, the selection type, is | |
1693 | @code{PRIMARY}. | |
1694 | ||
1695 | The @var{data-type} argument specifies the form of data conversion to | |
1696 | use, to convert the raw data obtained from another X client into Lisp | |
1697 | data. Meaningful values include @code{TEXT}, @code{STRING}, | |
1698 | @code{UTF8_STRING}, @code{TARGETS}, @code{LENGTH}, @code{DELETE}, | |
1699 | @code{FILE_NAME}, @code{CHARACTER_POSITION}, @code{NAME}, | |
1700 | @code{LINE_NUMBER}, @code{COLUMN_NUMBER}, @code{OWNER_OS}, | |
1701 | @code{HOST_NAME}, @code{USER}, @code{CLASS}, @code{ATOM}, and | |
1702 | @code{INTEGER}. (These are symbols with upper-case names in accord | |
1703 | with X conventions.) The default for @var{data-type} is | |
1704 | @code{STRING}. | |
1705 | @end defun | |
1706 | ||
1707 | @cindex cut buffer | |
1708 | The X server also has a set of eight numbered @dfn{cut buffers} which can | |
1709 | store text or other data being moved between applications. Cut buffers | |
1710 | are considered obsolete, but Emacs supports them for the sake of X | |
1711 | clients that still use them. Cut buffers are numbered from 0 to 7. | |
1712 | ||
1713 | @defun x-get-cut-buffer &optional n | |
1714 | This function returns the contents of cut buffer number @var{n}. | |
1715 | If omitted @var{n} defaults to 0. | |
1716 | @end defun | |
1717 | ||
1718 | @defun x-set-cut-buffer string &optional push | |
1719 | @anchor{Definition of x-set-cut-buffer} | |
1720 | This function stores @var{string} into the first cut buffer (cut buffer | |
1721 | 0). If @var{push} is @code{nil}, only the first cut buffer is changed. | |
1722 | If @var{push} is non-@code{nil}, that says to move the values down | |
1723 | through the series of cut buffers, much like the way successive kills in | |
1724 | Emacs move down the kill ring. In other words, the previous value of | |
1725 | the first cut buffer moves into the second cut buffer, and the second to | |
1726 | the third, and so on through all eight cut buffers. | |
1727 | @end defun | |
1728 | ||
1729 | @defvar selection-coding-system | |
1730 | This variable specifies the coding system to use when reading and | |
1731 | writing selections or the clipboard. @xref{Coding | |
1732 | Systems}. The default is @code{compound-text-with-extensions}, which | |
1733 | converts to the text representation that X11 normally uses. | |
1734 | @end defvar | |
1735 | ||
1736 | @cindex clipboard support (for MS-Windows) | |
1737 | When Emacs runs on MS-Windows, it does not implement X selections in | |
1738 | general, but it does support the clipboard. @code{x-get-selection} | |
1739 | and @code{x-set-selection} on MS-Windows support the text data type | |
1740 | only; if the clipboard holds other types of data, Emacs treats the | |
1741 | clipboard as empty. | |
1742 | ||
1743 | @cindex scrap support (for Mac OS) | |
1744 | On Mac OS, selection-like data transfer between applications is | |
1745 | performed through a mechanism called @dfn{scraps}. The clipboard is a | |
1746 | particular scrap named @code{com.apple.scrap.clipboard}. Types of scrap | |
1747 | data are called @dfn{scrap flavor types}, which are identified by | |
1748 | four-char codes such as @code{TEXT}. Emacs associates a selection with | |
1749 | a scrap, and a selection type with a scrap flavor type via | |
1750 | @code{mac-scrap-name} and @code{mac-ostype} properties, respectively. | |
1751 | ||
1752 | @example | |
1753 | (get 'CLIPBOARD 'mac-scrap-name) | |
1754 | @result{} "com.apple.scrap.clipboard" | |
1755 | (get 'com.apple.traditional-mac-plain-text 'mac-ostype) | |
1756 | @result{} "TEXT" | |
1757 | @end example | |
1758 | ||
1759 | Conventionally, selection types for scrap flavor types on Mac OS have | |
1760 | the form of @acronym{UTI, Uniform Type Identifier} such as | |
1761 | @code{com.apple.traditional-mac-plain-text}, | |
1762 | @code{public.utf16-plain-text}, and @code{public.file-url}. | |
1763 | ||
1764 | @defopt x-select-enable-clipboard | |
1765 | If this is non-@code{nil}, the Emacs yank functions consult the | |
1766 | clipboard before the primary selection, and the kill functions store in | |
1767 | the clipboard as well as the primary selection. Otherwise they do not | |
1768 | access the clipboard at all. The default is @code{nil} on most systems, | |
1769 | but @code{t} on MS-Windows and Mac. | |
1770 | @end defopt | |
1771 | ||
1772 | @node Drag and Drop | |
1773 | @section Drag and Drop | |
1774 | ||
1775 | @vindex x-dnd-test-function | |
1776 | @vindex x-dnd-known-types | |
1777 | When a user drags something from another application over Emacs, that other | |
1778 | application expects Emacs to tell it if Emacs can handle the data that is | |
1779 | dragged. The variable @code{x-dnd-test-function} is used by Emacs to determine | |
1780 | what to reply. The default value is @code{x-dnd-default-test-function} | |
1781 | which accepts drops if the type of the data to be dropped is present in | |
1782 | @code{x-dnd-known-types}. You can customize @code{x-dnd-test-function} and/or | |
1783 | @code{x-dnd-known-types} if you want Emacs to accept or reject drops based | |
1784 | on some other criteria. | |
1785 | ||
1786 | @vindex x-dnd-types-alist | |
1787 | If you want to change the way Emacs handles drop of different types | |
1788 | or add a new type, customize @code{x-dnd-types-alist}. This requires | |
1789 | detailed knowledge of what types other applications use for drag and | |
1790 | drop. | |
1791 | ||
1792 | @vindex dnd-protocol-alist | |
1793 | When an URL is dropped on Emacs it may be a file, but it may also be | |
1794 | another URL type (ftp, http, etc.). Emacs first checks | |
1795 | @code{dnd-protocol-alist} to determine what to do with the URL. If | |
1796 | there is no match there and if @code{browse-url-browser-function} is | |
1797 | an alist, Emacs looks for a match there. If no match is found the | |
1798 | text for the URL is inserted. If you want to alter Emacs behavior, | |
1799 | you can customize these variables. | |
1800 | ||
1801 | @node Color Names | |
1802 | @section Color Names | |
1803 | ||
1804 | @cindex color names | |
1805 | @cindex specify color | |
1806 | @cindex numerical RGB color specification | |
1807 | A color name is text (usually in a string) that specifies a color. | |
1808 | Symbolic names such as @samp{black}, @samp{white}, @samp{red}, etc., | |
1809 | are allowed; use @kbd{M-x list-colors-display} to see a list of | |
1810 | defined names. You can also specify colors numerically in forms such | |
1811 | as @samp{#@var{rgb}} and @samp{RGB:@var{r}/@var{g}/@var{b}}, where | |
1812 | @var{r} specifies the red level, @var{g} specifies the green level, | |
1813 | and @var{b} specifies the blue level. You can use either one, two, | |
1814 | three, or four hex digits for @var{r}; then you must use the same | |
1815 | number of hex digits for all @var{g} and @var{b} as well, making | |
1816 | either 3, 6, 9 or 12 hex digits in all. (See the documentation of the | |
1817 | X Window System for more details about numerical RGB specification of | |
1818 | colors.) | |
1819 | ||
1820 | These functions provide a way to determine which color names are | |
1821 | valid, and what they look like. In some cases, the value depends on the | |
1822 | @dfn{selected frame}, as described below; see @ref{Input Focus}, for the | |
1823 | meaning of the term ``selected frame.'' | |
1824 | ||
1825 | @defun color-defined-p color &optional frame | |
1826 | This function reports whether a color name is meaningful. It returns | |
1827 | @code{t} if so; otherwise, @code{nil}. The argument @var{frame} says | |
1828 | which frame's display to ask about; if @var{frame} is omitted or | |
1829 | @code{nil}, the selected frame is used. | |
1830 | ||
1831 | Note that this does not tell you whether the display you are using | |
1832 | really supports that color. When using X, you can ask for any defined | |
1833 | color on any kind of display, and you will get some result---typically, | |
1834 | the closest it can do. To determine whether a frame can really display | |
1835 | a certain color, use @code{color-supported-p} (see below). | |
1836 | ||
1837 | @findex x-color-defined-p | |
1838 | This function used to be called @code{x-color-defined-p}, | |
1839 | and that name is still supported as an alias. | |
1840 | @end defun | |
1841 | ||
1842 | @defun defined-colors &optional frame | |
1843 | This function returns a list of the color names that are defined | |
1844 | and supported on frame @var{frame} (default, the selected frame). | |
1845 | If @var{frame} does not support colors, the value is @code{nil}. | |
1846 | ||
1847 | @findex x-defined-colors | |
1848 | This function used to be called @code{x-defined-colors}, | |
1849 | and that name is still supported as an alias. | |
1850 | @end defun | |
1851 | ||
1852 | @defun color-supported-p color &optional frame background-p | |
1853 | This returns @code{t} if @var{frame} can really display the color | |
1854 | @var{color} (or at least something close to it). If @var{frame} is | |
1855 | omitted or @code{nil}, the question applies to the selected frame. | |
1856 | ||
1857 | Some terminals support a different set of colors for foreground and | |
1858 | background. If @var{background-p} is non-@code{nil}, that means you are | |
1859 | asking whether @var{color} can be used as a background; otherwise you | |
1860 | are asking whether it can be used as a foreground. | |
1861 | ||
1862 | The argument @var{color} must be a valid color name. | |
1863 | @end defun | |
1864 | ||
1865 | @defun color-gray-p color &optional frame | |
1866 | This returns @code{t} if @var{color} is a shade of gray, as defined on | |
1867 | @var{frame}'s display. If @var{frame} is omitted or @code{nil}, the | |
1868 | question applies to the selected frame. If @var{color} is not a valid | |
1869 | color name, this function returns @code{nil}. | |
1870 | @end defun | |
1871 | ||
1872 | @defun color-values color &optional frame | |
1873 | @cindex rgb value | |
1874 | This function returns a value that describes what @var{color} should | |
1875 | ideally look like on @var{frame}. If @var{color} is defined, the | |
1876 | value is a list of three integers, which give the amount of red, the | |
1877 | amount of green, and the amount of blue. Each integer ranges in | |
1878 | principle from 0 to 65535, but some displays may not use the full | |
1879 | range. This three-element list is called the @dfn{rgb values} of the | |
1880 | color. | |
1881 | ||
1882 | If @var{color} is not defined, the value is @code{nil}. | |
1883 | ||
1884 | @example | |
1885 | (color-values "black") | |
1886 | @result{} (0 0 0) | |
1887 | (color-values "white") | |
1888 | @result{} (65280 65280 65280) | |
1889 | (color-values "red") | |
1890 | @result{} (65280 0 0) | |
1891 | (color-values "pink") | |
1892 | @result{} (65280 49152 51968) | |
1893 | (color-values "hungry") | |
1894 | @result{} nil | |
1895 | @end example | |
1896 | ||
1897 | The color values are returned for @var{frame}'s display. If | |
1898 | @var{frame} is omitted or @code{nil}, the information is returned for | |
1899 | the selected frame's display. If the frame cannot display colors, the | |
1900 | value is @code{nil}. | |
1901 | ||
1902 | @findex x-color-values | |
1903 | This function used to be called @code{x-color-values}, | |
1904 | and that name is still supported as an alias. | |
1905 | @end defun | |
1906 | ||
1907 | @node Text Terminal Colors | |
1908 | @section Text Terminal Colors | |
1909 | @cindex colors on text-only terminals | |
1910 | ||
1911 | Text-only terminals usually support only a small number of colors, | |
1912 | and the computer uses small integers to select colors on the terminal. | |
1913 | This means that the computer cannot reliably tell what the selected | |
1914 | color looks like; instead, you have to inform your application which | |
1915 | small integers correspond to which colors. However, Emacs does know | |
1916 | the standard set of colors and will try to use them automatically. | |
1917 | ||
1918 | The functions described in this section control how terminal colors | |
1919 | are used by Emacs. | |
1920 | ||
1921 | Several of these functions use or return @dfn{rgb values}, described | |
1922 | in @ref{Color Names}. | |
1923 | ||
1924 | These functions accept a display (either a frame or the name of a | |
1925 | terminal) as an optional argument. We hope in the future to make Emacs | |
1926 | support more than one text-only terminal at one time; then this argument | |
1927 | will specify which terminal to operate on (the default being the | |
1928 | selected frame's terminal; @pxref{Input Focus}). At present, though, | |
1929 | the @var{frame} argument has no effect. | |
1930 | ||
1931 | @defun tty-color-define name number &optional rgb frame | |
1932 | This function associates the color name @var{name} with | |
1933 | color number @var{number} on the terminal. | |
1934 | ||
1935 | The optional argument @var{rgb}, if specified, is an rgb value, a list | |
1936 | of three numbers that specify what the color actually looks like. | |
1937 | If you do not specify @var{rgb}, then this color cannot be used by | |
1938 | @code{tty-color-approximate} to approximate other colors, because | |
1939 | Emacs will not know what it looks like. | |
1940 | @end defun | |
1941 | ||
1942 | @defun tty-color-clear &optional frame | |
1943 | This function clears the table of defined colors for a text-only terminal. | |
1944 | @end defun | |
1945 | ||
1946 | @defun tty-color-alist &optional frame | |
1947 | This function returns an alist recording the known colors supported by a | |
1948 | text-only terminal. | |
1949 | ||
1950 | Each element has the form @code{(@var{name} @var{number} . @var{rgb})} | |
1951 | or @code{(@var{name} @var{number})}. Here, @var{name} is the color | |
1952 | name, @var{number} is the number used to specify it to the terminal. | |
1953 | If present, @var{rgb} is a list of three color values (for red, green, | |
1954 | and blue) that says what the color actually looks like. | |
1955 | @end defun | |
1956 | ||
1957 | @defun tty-color-approximate rgb &optional frame | |
1958 | This function finds the closest color, among the known colors | |
1959 | supported for @var{display}, to that described by the rgb value | |
1960 | @var{rgb} (a list of color values). The return value is an element of | |
1961 | @code{tty-color-alist}. | |
1962 | @end defun | |
1963 | ||
1964 | @defun tty-color-translate color &optional frame | |
1965 | This function finds the closest color to @var{color} among the known | |
1966 | colors supported for @var{display} and returns its index (an integer). | |
1967 | If the name @var{color} is not defined, the value is @code{nil}. | |
1968 | @end defun | |
1969 | ||
1970 | @node Resources | |
1971 | @section X Resources | |
1972 | ||
1973 | @defun x-get-resource attribute class &optional component subclass | |
1974 | The function @code{x-get-resource} retrieves a resource value from the X | |
1975 | Window defaults database. | |
1976 | ||
1977 | Resources are indexed by a combination of a @dfn{key} and a @dfn{class}. | |
1978 | This function searches using a key of the form | |
1979 | @samp{@var{instance}.@var{attribute}} (where @var{instance} is the name | |
1980 | under which Emacs was invoked), and using @samp{Emacs.@var{class}} as | |
1981 | the class. | |
1982 | ||
1983 | The optional arguments @var{component} and @var{subclass} add to the key | |
1984 | and the class, respectively. You must specify both of them or neither. | |
1985 | If you specify them, the key is | |
1986 | @samp{@var{instance}.@var{component}.@var{attribute}}, and the class is | |
1987 | @samp{Emacs.@var{class}.@var{subclass}}. | |
1988 | @end defun | |
1989 | ||
1990 | @defvar x-resource-class | |
1991 | This variable specifies the application name that @code{x-get-resource} | |
1992 | should look up. The default value is @code{"Emacs"}. You can examine X | |
1993 | resources for application names other than ``Emacs'' by binding this | |
1994 | variable to some other string, around a call to @code{x-get-resource}. | |
1995 | @end defvar | |
1996 | ||
1997 | @defvar x-resource-name | |
1998 | This variable specifies the instance name that @code{x-get-resource} | |
1999 | should look up. The default value is the name Emacs was invoked with, | |
2000 | or the value specified with the @samp{-name} or @samp{-rn} switches. | |
2001 | @end defvar | |
2002 | ||
2003 | To illustrate some of the above, suppose that you have the line: | |
2004 | ||
2005 | @example | |
2006 | xterm.vt100.background: yellow | |
2007 | @end example | |
2008 | ||
2009 | @noindent | |
2010 | in your X resources file (whose name is usually @file{~/.Xdefaults} | |
2011 | or @file{~/.Xresources}). Then: | |
2012 | ||
2013 | @example | |
2014 | @group | |
2015 | (let ((x-resource-class "XTerm") (x-resource-name "xterm")) | |
2016 | (x-get-resource "vt100.background" "VT100.Background")) | |
2017 | @result{} "yellow" | |
2018 | @end group | |
2019 | @group | |
2020 | (let ((x-resource-class "XTerm") (x-resource-name "xterm")) | |
2021 | (x-get-resource "background" "VT100" "vt100" "Background")) | |
2022 | @result{} "yellow" | |
2023 | @end group | |
2024 | @end example | |
2025 | ||
2026 | @xref{X Resources,, X Resources, emacs, The GNU Emacs Manual}. | |
2027 | ||
2028 | @node Display Feature Testing | |
2029 | @section Display Feature Testing | |
2030 | @cindex display feature testing | |
2031 | ||
2032 | The functions in this section describe the basic capabilities of a | |
2033 | particular display. Lisp programs can use them to adapt their behavior | |
2034 | to what the display can do. For example, a program that ordinarily uses | |
2035 | a popup menu could use the minibuffer if popup menus are not supported. | |
2036 | ||
2037 | The optional argument @var{display} in these functions specifies which | |
2038 | display to ask the question about. It can be a display name, a frame | |
2039 | (which designates the display that frame is on), or @code{nil} (which | |
2040 | refers to the selected frame's display, @pxref{Input Focus}). | |
2041 | ||
2042 | @xref{Color Names}, @ref{Text Terminal Colors}, for other functions to | |
2043 | obtain information about displays. | |
2044 | ||
2045 | @defun display-popup-menus-p &optional display | |
2046 | This function returns @code{t} if popup menus are supported on | |
2047 | @var{display}, @code{nil} if not. Support for popup menus requires that | |
2048 | the mouse be available, since the user cannot choose menu items without | |
2049 | a mouse. | |
2050 | @end defun | |
2051 | ||
2052 | @defun display-graphic-p &optional display | |
2053 | This function returns @code{t} if @var{display} is a graphic display | |
2054 | capable of displaying several frames and several different fonts at | |
2055 | once. This is true for displays that use a window system such as X, and | |
2056 | false for text-only terminals. | |
2057 | @end defun | |
2058 | ||
2059 | @defun display-mouse-p &optional display | |
2060 | @cindex mouse, availability | |
2061 | This function returns @code{t} if @var{display} has a mouse available, | |
2062 | @code{nil} if not. | |
2063 | @end defun | |
2064 | ||
2065 | @defun display-color-p &optional display | |
2066 | @findex x-display-color-p | |
2067 | This function returns @code{t} if the screen is a color screen. | |
2068 | It used to be called @code{x-display-color-p}, and that name | |
2069 | is still supported as an alias. | |
2070 | @end defun | |
2071 | ||
2072 | @defun display-grayscale-p &optional display | |
2073 | This function returns @code{t} if the screen can display shades of gray. | |
2074 | (All color displays can do this.) | |
2075 | @end defun | |
2076 | ||
2077 | @defun display-supports-face-attributes-p attributes &optional display | |
2078 | @anchor{Display Face Attribute Testing} | |
2079 | This function returns non-@code{nil} if all the face attributes in | |
2080 | @var{attributes} are supported (@pxref{Face Attributes}). | |
2081 | ||
2082 | The definition of `supported' is somewhat heuristic, but basically | |
2083 | means that a face containing all the attributes in @var{attributes}, | |
2084 | when merged with the default face for display, can be represented in a | |
2085 | way that's | |
2086 | ||
2087 | @enumerate | |
2088 | @item | |
2089 | different in appearance than the default face, and | |
2090 | ||
2091 | @item | |
2092 | `close in spirit' to what the attributes specify, if not exact. | |
2093 | @end enumerate | |
2094 | ||
2095 | Point (2) implies that a @code{:weight black} attribute will be | |
2096 | satisfied by any display that can display bold, as will | |
2097 | @code{:foreground "yellow"} as long as some yellowish color can be | |
2098 | displayed, but @code{:slant italic} will @emph{not} be satisfied by | |
2099 | the tty display code's automatic substitution of a `dim' face for | |
2100 | italic. | |
2101 | @end defun | |
2102 | ||
2103 | @defun display-selections-p &optional display | |
2104 | This function returns @code{t} if @var{display} supports selections. | |
2105 | Windowed displays normally support selections, but they may also be | |
2106 | supported in some other cases. | |
2107 | @end defun | |
2108 | ||
2109 | @defun display-images-p &optional display | |
2110 | This function returns @code{t} if @var{display} can display images. | |
2111 | Windowed displays ought in principle to handle images, but some | |
2112 | systems lack the support for that. On a display that does not support | |
2113 | images, Emacs cannot display a tool bar. | |
2114 | @end defun | |
2115 | ||
2116 | @defun display-screens &optional display | |
2117 | This function returns the number of screens associated with the display. | |
2118 | @end defun | |
2119 | ||
2120 | @defun display-pixel-height &optional display | |
2121 | This function returns the height of the screen in pixels. | |
2122 | On a character terminal, it gives the height in characters. | |
2123 | ||
2124 | For graphical terminals, note that on ``multi-monitor'' setups this | |
2125 | refers to the pixel width for all physical monitors associated with | |
2126 | @var{display}. @xref{Multiple Displays}. | |
2127 | @end defun | |
2128 | ||
2129 | @defun display-pixel-width &optional display | |
2130 | This function returns the width of the screen in pixels. | |
2131 | On a character terminal, it gives the width in characters. | |
2132 | ||
2133 | For graphical terminals, note that on ``multi-monitor'' setups this | |
2134 | refers to the pixel width for all physical monitors associated with | |
2135 | @var{display}. @xref{Multiple Displays}. | |
2136 | @end defun | |
2137 | ||
2138 | @defun display-mm-height &optional display | |
2139 | This function returns the height of the screen in millimeters, | |
2140 | or @code{nil} if Emacs cannot get that information. | |
2141 | @end defun | |
2142 | ||
2143 | @defun display-mm-width &optional display | |
2144 | This function returns the width of the screen in millimeters, | |
2145 | or @code{nil} if Emacs cannot get that information. | |
2146 | @end defun | |
2147 | ||
2148 | @defvar display-mm-dimensions-alist | |
2149 | This variable allows the user to specify the dimensions of graphical | |
2150 | displays returned by @code{display-mm-height} and | |
2151 | @code{display-mm-width} in case the system provides incorrect values. | |
2152 | @end defvar | |
2153 | ||
2154 | @defun display-backing-store &optional display | |
2155 | This function returns the backing store capability of the display. | |
2156 | Backing store means recording the pixels of windows (and parts of | |
2157 | windows) that are not exposed, so that when exposed they can be | |
2158 | displayed very quickly. | |
2159 | ||
2160 | Values can be the symbols @code{always}, @code{when-mapped}, or | |
2161 | @code{not-useful}. The function can also return @code{nil} | |
2162 | when the question is inapplicable to a certain kind of display. | |
2163 | @end defun | |
2164 | ||
2165 | @defun display-save-under &optional display | |
2166 | This function returns non-@code{nil} if the display supports the | |
2167 | SaveUnder feature. That feature is used by pop-up windows | |
2168 | to save the pixels they obscure, so that they can pop down | |
2169 | quickly. | |
2170 | @end defun | |
2171 | ||
2172 | @defun display-planes &optional display | |
2173 | This function returns the number of planes the display supports. | |
2174 | This is typically the number of bits per pixel. | |
2175 | For a tty display, it is log to base two of the number of colors supported. | |
2176 | @end defun | |
2177 | ||
2178 | @defun display-visual-class &optional display | |
2179 | This function returns the visual class for the screen. The value is one | |
2180 | of the symbols @code{static-gray}, @code{gray-scale}, | |
2181 | @code{static-color}, @code{pseudo-color}, @code{true-color}, and | |
2182 | @code{direct-color}. | |
2183 | @end defun | |
2184 | ||
2185 | @defun display-color-cells &optional display | |
2186 | This function returns the number of color cells the screen supports. | |
2187 | @end defun | |
2188 | ||
2189 | These functions obtain additional information specifically | |
2190 | about X displays. | |
2191 | ||
2192 | @defun x-server-version &optional display | |
2193 | This function returns the list of version numbers of the X server | |
2194 | running the display. The value is a list of three integers: the major | |
2195 | and minor version numbers of the X protocol, and the | |
2196 | distributor-specific release number of the X server software itself. | |
2197 | @end defun | |
2198 | ||
2199 | @defun x-server-vendor &optional display | |
2200 | This function returns the ``vendor'' that provided the X server | |
2201 | software (as a string). Really this means whoever distributes the X | |
2202 | server. | |
2203 | ||
2204 | When the developers of X labelled software distributors as | |
2205 | ``vendors,'' they showed their false assumption that no system could | |
2206 | ever be developed and distributed noncommercially. | |
2207 | @end defun | |
2208 | ||
2209 | @ignore | |
2210 | @defvar x-no-window-manager | |
2211 | This variable's value is @code{t} if no X window manager is in use. | |
2212 | @end defvar | |
2213 | @end ignore | |
2214 | ||
2215 | @ignore | |
2216 | @item | |
2217 | The functions @code{x-pixel-width} and @code{x-pixel-height} return the | |
2218 | width and height of an X Window frame, measured in pixels. | |
2219 | @end ignore | |
2220 | ||
2221 | @ignore | |
2222 | arch-tag: 94977df6-3dca-4730-b57b-c6329e9282ba | |
2223 | @end ignore |