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diff --git a/lispref/frames.texi b/lispref/frames.texi deleted file mode 100644 index 7d2ea7cf70e..00000000000 --- a/lispref/frames.texi +++ /dev/null @@ -1,2208 +0,0 @@ -@c -*-texinfo-*- -@c This is part of the GNU Emacs Lisp Reference Manual. -@c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1998, 1999, 2001, -@c 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc. -@c See the file elisp.texi for copying conditions. -@setfilename ../info/frames -@node Frames, Positions, Windows, Top -@chapter Frames -@cindex frame - - In Emacs editing, A @dfn{frame} is a screen object that contains one -or more Emacs windows. It's the kind of object that is called a -``window'' in the terminology of graphical environments; but we can't -call it a ``window'' here, because Emacs uses that word in a different -way. - - A frame initially contains a single main window and/or a minibuffer -window; you can subdivide the main window vertically or horizontally -into smaller windows. In Emacs Lisp, a @dfn{frame object} is a Lisp -object that represents a frame on the screen. - -@cindex terminal frame - When Emacs runs on a text-only terminal, it starts with one -@dfn{terminal frame}. If you create additional ones, Emacs displays -one and only one at any given time---on the terminal screen, of course. - -@cindex window frame - When Emacs communicates directly with a supported window system, such -as X, it does not have a terminal frame; instead, it starts with -a single @dfn{window frame}, but you can create more, and Emacs can -display several such frames at once as is usual for window systems. - -@defun framep object -This predicate returns a non-@code{nil} value if @var{object} is a -frame, and @code{nil} otherwise. For a frame, the value indicates which -kind of display the frame uses: - -@table @code -@item x -The frame is displayed in an X window. -@item t -A terminal frame on a character display. -@item mac -The frame is displayed on a Macintosh. -@item w32 -The frame is displayed on MS-Windows 9X/NT. -@item pc -The frame is displayed on an MS-DOS terminal. -@end table -@end defun - -@menu -* Creating Frames:: Creating additional frames. -* Multiple Displays:: Creating frames on other displays. -* Frame Parameters:: Controlling frame size, position, font, etc. -* Frame Titles:: Automatic updating of frame titles. -* Deleting Frames:: Frames last until explicitly deleted. -* Finding All Frames:: How to examine all existing frames. -* Frames and Windows:: A frame contains windows; - display of text always works through windows. -* Minibuffers and Frames:: How a frame finds the minibuffer to use. -* Input Focus:: Specifying the selected frame. -* Visibility of Frames:: Frames may be visible or invisible, or icons. -* Raising and Lowering:: Raising a frame makes it hide other windows; - lowering it makes the others hide it. -* Frame Configurations:: Saving the state of all frames. -* Mouse Tracking:: Getting events that say when the mouse moves. -* Mouse Position:: Asking where the mouse is, or moving it. -* Pop-Up Menus:: Displaying a menu for the user to select from. -* Dialog Boxes:: Displaying a box to ask yes or no. -* Pointer Shape:: Specifying the shape of the mouse pointer. -* Window System Selections:: Transferring text to and from other X clients. -* Drag and Drop:: Internals of Drag-and-Drop implementation. -* Color Names:: Getting the definitions of color names. -* Text Terminal Colors:: Defining colors for text-only terminals. -* Resources:: Getting resource values from the server. -* Display Feature Testing:: Determining the features of a terminal. -@end menu - - @xref{Display}, for information about the related topic of -controlling Emacs redisplay. - -@node Creating Frames -@section Creating Frames - -To create a new frame, call the function @code{make-frame}. - -@defun make-frame &optional alist -This function creates and returns a new frame, displaying the current -buffer. If you are using a supported window system, it makes a window -frame; otherwise, it makes a terminal frame. - -The argument is an alist specifying frame parameters. Any parameters -not mentioned in @var{alist} default according to the value of the -variable @code{default-frame-alist}; parameters not specified even there -default from the standard X resources or whatever is used instead on -your system. - -The set of possible parameters depends in principle on what kind of -window system Emacs uses to display its frames. @xref{Window Frame -Parameters}, for documentation of individual parameters you can specify. - -This function itself does not make the new frame the selected frame. -@xref{Input Focus}. The previously selected frame remains selected. -However, the window system may select the new frame for its own reasons, -for instance if the frame appears under the mouse pointer and your -setup is for focus to follow the pointer. -@end defun - -@defvar before-make-frame-hook -A normal hook run by @code{make-frame} before it actually creates the -frame. -@end defvar - -@defvar after-make-frame-functions -An abnormal hook run by @code{make-frame} after it creates the frame. -Each function in @code{after-make-frame-functions} receives one argument, the -frame just created. -@end defvar - -@node Multiple Displays -@section Multiple Displays -@cindex multiple X displays -@cindex displays, multiple - - A single Emacs can talk to more than one X display. -Initially, Emacs uses just one display---the one chosen with the -@code{DISPLAY} environment variable or with the @samp{--display} option -(@pxref{Initial Options,,, emacs, The GNU Emacs Manual}). To connect to -another display, use the command @code{make-frame-on-display} or specify -the @code{display} frame parameter when you create the frame. - - Emacs treats each X server as a separate terminal, giving each one its -own selected frame and its own minibuffer windows. However, only one of -those frames is ``@emph{the} selected frame'' at any given moment, see -@ref{Input Focus}. - - A few Lisp variables are @dfn{terminal-local}; that is, they have a -separate binding for each terminal. The binding in effect at any time -is the one for the terminal that the currently selected frame belongs -to. These variables include @code{default-minibuffer-frame}, -@code{defining-kbd-macro}, @code{last-kbd-macro}, and -@code{system-key-alist}. They are always terminal-local, and can never -be buffer-local (@pxref{Buffer-Local Variables}) or frame-local. - - A single X server can handle more than one screen. A display name -@samp{@var{host}:@var{server}.@var{screen}} has three parts; the last -part specifies the screen number for a given server. When you use two -screens belonging to one server, Emacs knows by the similarity in their -names that they share a single keyboard, and it treats them as a single -terminal. - - Note that some graphical terminals can output to more than a one -monitor (or other output device) at the same time. On these -``multi-monitor'' setups, a single @var{display} value controls the -output to all the physical monitors. In this situation, there is -currently no platform-independent way for Emacs to distinguish between -the different physical monitors. - -@deffn Command make-frame-on-display display &optional parameters -This creates and returns a new frame on display @var{display}, taking -the other frame parameters from @var{parameters}. Aside from the -@var{display} argument, it is like @code{make-frame} (@pxref{Creating -Frames}). -@end deffn - -@defun x-display-list -This returns a list that indicates which X displays Emacs has a -connection to. The elements of the list are strings, and each one is -a display name. -@end defun - -@defun x-open-connection display &optional xrm-string must-succeed -This function opens a connection to the X display @var{display}. It -does not create a frame on that display, but it permits you to check -that communication can be established with that display. - -The optional argument @var{xrm-string}, if not @code{nil}, is a -string of resource names and values, in the same format used in the -@file{.Xresources} file. The values you specify override the resource -values recorded in the X server itself; they apply to all Emacs frames -created on this display. Here's an example of what this string might -look like: - -@example -"*BorderWidth: 3\n*InternalBorder: 2\n" -@end example - -@xref{X Resources,, X Resources, emacs, The GNU Emacs Manual}. - -If @var{must-succeed} is non-@code{nil}, failure to open the connection -terminates Emacs. Otherwise, it is an ordinary Lisp error. -@end defun - -@defun x-close-connection display -This function closes the connection to display @var{display}. Before -you can do this, you must first delete all the frames that were open on -that display (@pxref{Deleting Frames}). -@end defun - -@node Frame Parameters -@section Frame Parameters -@cindex frame parameters - - A frame has many parameters that control its appearance and behavior. -Just what parameters a frame has depends on what display mechanism it -uses. - - Frame parameters exist mostly for the sake of window systems. A -terminal frame has a few parameters, mostly for compatibility's sake; -only the @code{height}, @code{width}, @code{name}, @code{title}, -@code{menu-bar-lines}, @code{buffer-list} and @code{buffer-predicate} -parameters do something special. If the terminal supports colors, the -parameters @code{foreground-color}, @code{background-color}, -@code{background-mode} and @code{display-type} are also meaningful. - -@menu -* Parameter Access:: How to change a frame's parameters. -* Initial Parameters:: Specifying frame parameters when you make a frame. -* Window Frame Parameters:: List of frame parameters for window systems. -* Size and Position:: Changing the size and position of a frame. -* Geometry:: Parsing geometry specifications. -@end menu - -@node Parameter Access -@subsection Access to Frame Parameters - -These functions let you read and change the parameter values of a -frame. - -@defun frame-parameter frame parameter -This function returns the value of the parameter @var{parameter} (a -symbol) of @var{frame}. If @var{frame} is @code{nil}, it returns the -selected frame's parameter. If @var{frame} has no setting for -@var{parameter}, this function returns @code{nil}. -@end defun - -@defun frame-parameters &optional frame -The function @code{frame-parameters} returns an alist listing all the -parameters of @var{frame} and their values. If @var{frame} is -@code{nil} or omitted, this returns the selected frame's parameters -@end defun - -@defun modify-frame-parameters frame alist -This function alters the parameters of frame @var{frame} based on the -elements of @var{alist}. Each element of @var{alist} has the form -@code{(@var{parm} . @var{value})}, where @var{parm} is a symbol naming a -parameter. If you don't mention a parameter in @var{alist}, its value -doesn't change. If @var{frame} is @code{nil}, it defaults to the selected -frame. -@end defun - -@defun modify-all-frames-parameters alist -This function alters the frame parameters of all existing frames -according to @var{alist}, then modifies @code{default-frame-alist} -(and, if necessary, @code{initial-frame-alist}) to apply the same -parameter values to frames that will be created henceforth. -@end defun - -@node Initial Parameters -@subsection Initial Frame Parameters - -You can specify the parameters for the initial startup frame -by setting @code{initial-frame-alist} in your init file (@pxref{Init File}). - -@defvar initial-frame-alist -This variable's value is an alist of parameter values used when creating -the initial window frame. You can set this variable to specify the -appearance of the initial frame without altering subsequent frames. -Each element has the form: - -@example -(@var{parameter} . @var{value}) -@end example - -Emacs creates the initial frame before it reads your init -file. After reading that file, Emacs checks @code{initial-frame-alist}, -and applies the parameter settings in the altered value to the already -created initial frame. - -If these settings affect the frame geometry and appearance, you'll see -the frame appear with the wrong ones and then change to the specified -ones. If that bothers you, you can specify the same geometry and -appearance with X resources; those do take effect before the frame is -created. @xref{X Resources,, X Resources, emacs, The GNU Emacs Manual}. - -X resource settings typically apply to all frames. If you want to -specify some X resources solely for the sake of the initial frame, and -you don't want them to apply to subsequent frames, here's how to achieve -this. Specify parameters in @code{default-frame-alist} to override the -X resources for subsequent frames; then, to prevent these from affecting -the initial frame, specify the same parameters in -@code{initial-frame-alist} with values that match the X resources. -@end defvar - -If these parameters specify a separate minibuffer-only frame with -@code{(minibuffer . nil)}, and you have not created one, Emacs creates -one for you. - -@defvar minibuffer-frame-alist -This variable's value is an alist of parameter values used when creating -an initial minibuffer-only frame---if such a frame is needed, according -to the parameters for the main initial frame. -@end defvar - -@defvar default-frame-alist -This is an alist specifying default values of frame parameters for all -Emacs frames---the first frame, and subsequent frames. When using the X -Window System, you can get the same results by means of X resources -in many cases. - -Setting this variable does not affect existing frames. -@end defvar - -See also @code{special-display-frame-alist}. @xref{Definition of -special-display-frame-alist}. - -If you use options that specify window appearance when you invoke Emacs, -they take effect by adding elements to @code{default-frame-alist}. One -exception is @samp{-geometry}, which adds the specified position to -@code{initial-frame-alist} instead. @xref{Emacs Invocation,, Command -Line Arguments for Emacs Invocation, emacs, The GNU Emacs Manual}. - -@node Window Frame Parameters -@subsection Window Frame Parameters - - Just what parameters a frame has depends on what display mechanism -it uses. This section describes the parameters that have special -meanings on some or all kinds of terminals. Of these, @code{name}, -@code{title}, @code{height}, @code{width}, @code{buffer-list} and -@code{buffer-predicate} provide meaningful information in terminal -frames, and @code{tty-color-mode} is meaningful @emph{only} in -terminal frames. - -@menu -* Basic Parameters:: Parameters that are fundamental. -* Position Parameters:: The position of the frame on the screen. -* Size Parameters:: Frame's size. -* Layout Parameters:: Size of parts of the frame, and - enabling or disabling some parts. -* Buffer Parameters:: Which buffers have been or should be shown. -* Management Parameters:: Communicating with the window manager. -* Cursor Parameters:: Controlling the cursor appearance. -* Color Parameters:: Colors of various parts of the frame. -@end menu - -@node Basic Parameters -@subsubsection Basic Parameters - - These frame parameters give the most basic information about the -frame. @code{title} and @code{name} are meaningful on all terminals. - -@table @code -@item display -The display on which to open this frame. It should be a string of the -form @code{"@var{host}:@var{dpy}.@var{screen}"}, just like the -@code{DISPLAY} environment variable. - -@item display-type -This parameter describes the range of possible colors that can be used -in this frame. Its value is @code{color}, @code{grayscale} or -@code{mono}. - -@item title -If a frame has a non-@code{nil} title, it appears in the window system's -border for the frame, and also in the mode line of windows in that frame -if @code{mode-line-frame-identification} uses @samp{%F} -(@pxref{%-Constructs}). This is normally the case when Emacs is not -using a window system, and can only display one frame at a time. -@xref{Frame Titles}. - -@item name -The name of the frame. The frame name serves as a default for the frame -title, if the @code{title} parameter is unspecified or @code{nil}. If -you don't specify a name, Emacs sets the frame name automatically -(@pxref{Frame Titles}). - -If you specify the frame name explicitly when you create the frame, the -name is also used (instead of the name of the Emacs executable) when -looking up X resources for the frame. - -@item display-environment-variable -The value of the @code{DISPLAY} environment variable for the frame. It -is passed to child processes. - -@item term-environment-variable -The value of the @code{TERM} environment variable for the frame. It -is passed to child processes. -@end table - -@node Position Parameters -@subsubsection Position Parameters - - Position parameters' values are normally measured in pixels, but on -text-only terminals they count characters or lines instead. - -@table @code -@item left -The screen position of the left edge, in pixels, with respect to the -left edge of the screen. The value may be a positive number @var{pos}, -or a list of the form @code{(+ @var{pos})} which permits specifying a -negative @var{pos} value. - -A negative number @minus{}@var{pos}, or a list of the form @code{(- -@var{pos})}, actually specifies the position of the right edge of the -window with respect to the right edge of the screen. A positive value -of @var{pos} counts toward the left. @strong{Reminder:} if the -parameter is a negative integer @minus{}@var{pos}, then @var{pos} is -positive. - -Some window managers ignore program-specified positions. If you want to -be sure the position you specify is not ignored, specify a -non-@code{nil} value for the @code{user-position} parameter as well. - -@item top -The screen position of the top edge, in pixels, with respect to the -top edge of the screen. It works just like @code{left}, except vertically -instead of horizontally. - -@item icon-left -The screen position of the left edge @emph{of the frame's icon}, in -pixels, counting from the left edge of the screen. This takes effect if -and when the frame is iconified. - -If you specify a value for this parameter, then you must also specify -a value for @code{icon-top} and vice versa. The window manager may -ignore these two parameters. - -@item icon-top -The screen position of the top edge @emph{of the frame's icon}, in -pixels, counting from the top edge of the screen. This takes effect if -and when the frame is iconified. - -@item user-position -When you create a frame and specify its screen position with the -@code{left} and @code{top} parameters, use this parameter to say whether -the specified position was user-specified (explicitly requested in some -way by a human user) or merely program-specified (chosen by a program). -A non-@code{nil} value says the position was user-specified. - -Window managers generally heed user-specified positions, and some heed -program-specified positions too. But many ignore program-specified -positions, placing the window in a default fashion or letting the user -place it with the mouse. Some window managers, including @code{twm}, -let the user specify whether to obey program-specified positions or -ignore them. - -When you call @code{make-frame}, you should specify a non-@code{nil} -value for this parameter if the values of the @code{left} and @code{top} -parameters represent the user's stated preference; otherwise, use -@code{nil}. -@end table - -@node Size Parameters -@subsubsection Size Parameters - - Size parameters' values are normally measured in pixels, but on -text-only terminals they count characters or lines instead. - -@table @code -@item height -The height of the frame contents, in characters. (To get the height in -pixels, call @code{frame-pixel-height}; see @ref{Size and Position}.) - -@item width -The width of the frame contents, in characters. (To get the height in -pixels, call @code{frame-pixel-width}; see @ref{Size and Position}.) - -@item user-size -This does for the size parameters @code{height} and @code{width} what -the @code{user-position} parameter (see above) does for the position -parameters @code{top} and @code{left}. - -@item fullscreen -Specify that width, height or both shall be set to the size of the screen. -The value @code{fullwidth} specifies that width shall be the size of the -screen. The value @code{fullheight} specifies that height shall be the -size of the screen. The value @code{fullboth} specifies that both the -width and the height shall be set to the size of the screen. -@end table - -@node Layout Parameters -@subsubsection Layout Parameters - - These frame parameters enable or disable various parts of the -frame, or control their sizes. - -@table @code -@item border-width -The width in pixels of the frame's border. - -@item internal-border-width -The distance in pixels between text (or fringe) and the frame's border. - -@item vertical-scroll-bars -Whether the frame has scroll bars for vertical scrolling, and which side -of the frame they should be on. The possible values are @code{left}, -@code{right}, and @code{nil} for no scroll bars. - -@ignore -@item horizontal-scroll-bars -Whether the frame has scroll bars for horizontal scrolling -(non-@code{nil} means yes). Horizontal scroll bars are not currently -implemented. -@end ignore - -@item scroll-bar-width -The width of vertical scroll bars, in pixels, or @code{nil} meaning to -use the default width. - -@item left-fringe -@itemx right-fringe -The default width of the left and right fringes of windows in this -frame (@pxref{Fringes}). If either of these is zero, that effectively -removes the corresponding fringe. A value of @code{nil} stands for -the standard fringe width, which is the width needed to display the -fringe bitmaps. - -The combined fringe widths must add up to an integral number of -columns, so the actual default fringe widths for the frame may be -larger than the specified values. The extra width needed to reach an -acceptable total is distributed evenly between the left and right -fringe. However, you can force one fringe or the other to a precise -width by specifying that width as a negative integer. If both widths are -negative, only the left fringe gets the specified width. - -@item menu-bar-lines -The number of lines to allocate at the top of the frame for a menu -bar. The default is 1. A value of @code{nil} means don't display a -menu bar. @xref{Menu Bar}. (The X toolkit and GTK allow at most one -menu bar line; they treat larger values as 1.) - -@item tool-bar-lines -The number of lines to use for the tool bar. A value of @code{nil} -means don't display a tool bar. (GTK allows at most one tool bar line; -it treats larger values as 1.) - -@item line-spacing -Additional space to leave below each text line, in pixels (a positive -integer). @xref{Line Height}, for more information. -@end table - -@node Buffer Parameters -@subsubsection Buffer Parameters - - These frame parameters, meaningful on all kinds of terminals, deal -with which buffers have been, or should, be displayed in the frame. - -@table @code -@item minibuffer -Whether this frame has its own minibuffer. The value @code{t} means -yes, @code{nil} means no, @code{only} means this frame is just a -minibuffer. If the value is a minibuffer window (in some other frame), -the new frame uses that minibuffer. - -@item buffer-predicate -The buffer-predicate function for this frame. The function -@code{other-buffer} uses this predicate (from the selected frame) to -decide which buffers it should consider, if the predicate is not -@code{nil}. It calls the predicate with one argument, a buffer, once for -each buffer; if the predicate returns a non-@code{nil} value, it -considers that buffer. - -@item buffer-list -A list of buffers that have been selected in this frame, -ordered most-recently-selected first. - -@item unsplittable -If non-@code{nil}, this frame's window is never split automatically. -@end table - -@node Management Parameters -@subsubsection Window Management Parameters -@cindex window manager, and frame parameters - - These frame parameters, meaningful only on window system displays, -interact with the window manager. - -@table @code -@item visibility -The state of visibility of the frame. There are three possibilities: -@code{nil} for invisible, @code{t} for visible, and @code{icon} for -iconified. @xref{Visibility of Frames}. - -@item auto-raise -Whether selecting the frame raises it (non-@code{nil} means yes). - -@item auto-lower -Whether deselecting the frame lowers it (non-@code{nil} means yes). - -@item icon-type -The type of icon to use for this frame when it is iconified. If the -value is a string, that specifies a file containing a bitmap to use. -Any other non-@code{nil} value specifies the default bitmap icon (a -picture of a gnu); @code{nil} specifies a text icon. - -@item icon-name -The name to use in the icon for this frame, when and if the icon -appears. If this is @code{nil}, the frame's title is used. - -@item window-id -The number of the window-system window used by the frame -to contain the actual Emacs windows. - -@item outer-window-id -The number of the outermost window-system window used for the whole frame. - -@item wait-for-wm -If non-@code{nil}, tell Xt to wait for the window manager to confirm -geometry changes. Some window managers, including versions of Fvwm2 -and KDE, fail to confirm, so Xt hangs. Set this to @code{nil} to -prevent hanging with those window managers. - -@ignore -@item parent-id -@c ??? Not yet working. -The X window number of the window that should be the parent of this one. -Specifying this lets you create an Emacs window inside some other -application's window. (It is not certain this will be implemented; try -it and see if it works.) -@end ignore -@end table - -@node Cursor Parameters -@subsubsection Cursor Parameters - - This frame parameter controls the way the cursor looks. - -@table @code -@item cursor-type -How to display the cursor. Legitimate values are: - -@table @code -@item box -Display a filled box. (This is the default.) -@item hollow -Display a hollow box. -@item nil -Don't display a cursor. -@item bar -Display a vertical bar between characters. -@item (bar . @var{width}) -Display a vertical bar @var{width} pixels wide between characters. -@item hbar -Display a horizontal bar. -@item (hbar . @var{height}) -Display a horizontal bar @var{height} pixels high. -@end table -@end table - -@vindex cursor-type -The buffer-local variable @code{cursor-type} overrides the value of -the @code{cursor-type} frame parameter, but if it is @code{t}, that -means to use the cursor specified for the frame. - -@defvar blink-cursor-alist -This variable specifies how to blink the cursor. Each element has the -form @code{(@var{on-state} . @var{off-state})}. Whenever the cursor -type equals @var{on-state} (comparing using @code{equal}), the -corresponding @var{off-state} specifies what the cursor looks like -when it blinks ``off.'' Both @var{on-state} and @var{off-state} -should be suitable values for the @code{cursor-type} frame parameter. - -There are various defaults for how to blink each type of cursor, if -the type is not mentioned as an @var{on-state} here. Changes in this -variable do not take effect immediately, because the variable is -examined only when you specify the @code{cursor-type} parameter. -@end defvar - -@node Color Parameters -@subsubsection Color Parameters - - These frame parameters control the use of colors. - -@table @code -@item background-mode -This parameter is either @code{dark} or @code{light}, according -to whether the background color is a light one or a dark one. - -@item tty-color-mode -@cindex standard colors for character terminals -This parameter overrides the terminal's color support as given by the -system's terminal capabilities database in that this parameter's value -specifies the color mode to use in terminal frames. The value can be -either a symbol or a number. A number specifies the number of colors -to use (and, indirectly, what commands to issue to produce each -color). For example, @code{(tty-color-mode . 8)} specifies use of the -ANSI escape sequences for 8 standard text colors. A value of -1 turns -off color support. - -If the parameter's value is a symbol, it specifies a number through -the value of @code{tty-color-mode-alist}, and the associated number is -used instead. - -@item screen-gamma -@cindex gamma correction -If this is a number, Emacs performs ``gamma correction'' which adjusts -the brightness of all colors. The value should be the screen gamma of -your display, a floating point number. - -Usual PC monitors have a screen gamma of 2.2, so color values in -Emacs, and in X windows generally, are calibrated to display properly -on a monitor with that gamma value. If you specify 2.2 for -@code{screen-gamma}, that means no correction is needed. Other values -request correction, designed to make the corrected colors appear on -your screen the way they would have appeared without correction on an -ordinary monitor with a gamma value of 2.2. - -If your monitor displays colors too light, you should specify a -@code{screen-gamma} value smaller than 2.2. This requests correction -that makes colors darker. A screen gamma value of 1.5 may give good -results for LCD color displays. -@end table - -These frame parameters are semi-obsolete in that they are automatically -equivalent to particular face attributes of particular faces. -@xref{Standard Faces,,, emacs, The Emacs Manual}. - -@table @code -@item font -The name of the font for displaying text in the frame. This is a -string, either a valid font name for your system or the name of an Emacs -fontset (@pxref{Fontsets}). It is equivalent to the @code{font} -attribute of the @code{default} face. - -@item foreground-color -The color to use for the image of a character. It is equivalent to -the @code{:foreground} attribute of the @code{default} face. - -@item background-color -The color to use for the background of characters. It is equivalent to -the @code{:background} attribute of the @code{default} face. - -@item mouse-color -The color for the mouse pointer. It is equivalent to the @code{:background} -attribute of the @code{mouse} face. - -@item cursor-color -The color for the cursor that shows point. It is equivalent to the -@code{:background} attribute of the @code{cursor} face. - -@item border-color -The color for the border of the frame. It is equivalent to the -@code{:background} attribute of the @code{border} face. - -@item scroll-bar-foreground -If non-@code{nil}, the color for the foreground of scroll bars. It is -equivalent to the @code{:foreground} attribute of the -@code{scroll-bar} face. - -@item scroll-bar-background -If non-@code{nil}, the color for the background of scroll bars. It is -equivalent to the @code{:background} attribute of the -@code{scroll-bar} face. -@end table - -@node Size and Position -@subsection Frame Size And Position -@cindex size of frame -@cindex screen size -@cindex frame size -@cindex resize frame - - You can read or change the size and position of a frame using the -frame parameters @code{left}, @code{top}, @code{height}, and -@code{width}. Whatever geometry parameters you don't specify are chosen -by the window manager in its usual fashion. - - Here are some special features for working with sizes and positions. -(For the precise meaning of ``selected frame'' used by these functions, -see @ref{Input Focus}.) - -@defun set-frame-position frame left top -This function sets the position of the top left corner of @var{frame} to -@var{left} and @var{top}. These arguments are measured in pixels, and -normally count from the top left corner of the screen. - -Negative parameter values position the bottom edge of the window up from -the bottom edge of the screen, or the right window edge to the left of -the right edge of the screen. It would probably be better if the values -were always counted from the left and top, so that negative arguments -would position the frame partly off the top or left edge of the screen, -but it seems inadvisable to change that now. -@end defun - -@defun frame-height &optional frame -@defunx frame-width &optional frame -These functions return the height and width of @var{frame}, measured in -lines and columns. If you don't supply @var{frame}, they use the -selected frame. -@end defun - -@defun screen-height -@defunx screen-width -These functions are old aliases for @code{frame-height} and -@code{frame-width}. When you are using a non-window terminal, the size -of the frame is normally the same as the size of the terminal screen. -@end defun - -@defun frame-pixel-height &optional frame -@defunx frame-pixel-width &optional frame -These functions return the height and width of @var{frame}, measured in -pixels. If you don't supply @var{frame}, they use the selected frame. -@end defun - -@defun frame-char-height &optional frame -@defunx frame-char-width &optional frame -These functions return the height and width of a character in -@var{frame}, measured in pixels. The values depend on the choice of -font. If you don't supply @var{frame}, these functions use the selected -frame. -@end defun - -@defun set-frame-size frame cols rows -This function sets the size of @var{frame}, measured in characters; -@var{cols} and @var{rows} specify the new width and height. - -To set the size based on values measured in pixels, use -@code{frame-char-height} and @code{frame-char-width} to convert -them to units of characters. -@end defun - -@defun set-frame-height frame lines &optional pretend -This function resizes @var{frame} to a height of @var{lines} lines. The -sizes of existing windows in @var{frame} are altered proportionally to -fit. - -If @var{pretend} is non-@code{nil}, then Emacs displays @var{lines} -lines of output in @var{frame}, but does not change its value for the -actual height of the frame. This is only useful for a terminal frame. -Using a smaller height than the terminal actually implements may be -useful to reproduce behavior observed on a smaller screen, or if the -terminal malfunctions when using its whole screen. Setting the frame -height ``for real'' does not always work, because knowing the correct -actual size may be necessary for correct cursor positioning on a -terminal frame. -@end defun - -@defun set-frame-width frame width &optional pretend -This function sets the width of @var{frame}, measured in characters. -The argument @var{pretend} has the same meaning as in -@code{set-frame-height}. -@end defun - -@findex set-screen-height -@findex set-screen-width - The older functions @code{set-screen-height} and -@code{set-screen-width} were used to specify the height and width of the -screen, in Emacs versions that did not support multiple frames. They -are semi-obsolete, but still work; they apply to the selected frame. - -@node Geometry -@subsection Geometry - - Here's how to examine the data in an X-style window geometry -specification: - -@defun x-parse-geometry geom -@cindex geometry specification -The function @code{x-parse-geometry} converts a standard X window -geometry string to an alist that you can use as part of the argument to -@code{make-frame}. - -The alist describes which parameters were specified in @var{geom}, and -gives the values specified for them. Each element looks like -@code{(@var{parameter} . @var{value})}. The possible @var{parameter} -values are @code{left}, @code{top}, @code{width}, and @code{height}. - -For the size parameters, the value must be an integer. The position -parameter names @code{left} and @code{top} are not totally accurate, -because some values indicate the position of the right or bottom edges -instead. These are the @var{value} possibilities for the position -parameters: - -@table @asis -@item an integer -A positive integer relates the left edge or top edge of the window to -the left or top edge of the screen. A negative integer relates the -right or bottom edge of the window to the right or bottom edge of the -screen. - -@item @code{(+ @var{position})} -This specifies the position of the left or top edge of the window -relative to the left or top edge of the screen. The integer -@var{position} may be positive or negative; a negative value specifies a -position outside the screen. - -@item @code{(- @var{position})} -This specifies the position of the right or bottom edge of the window -relative to the right or bottom edge of the screen. The integer -@var{position} may be positive or negative; a negative value specifies a -position outside the screen. -@end table - -Here is an example: - -@example -(x-parse-geometry "35x70+0-0") - @result{} ((height . 70) (width . 35) - (top - 0) (left . 0)) -@end example -@end defun - -@node Frame Titles -@section Frame Titles -@cindex frame title - - Every frame has a @code{name} parameter; this serves as the default -for the frame title which window systems typically display at the top of -the frame. You can specify a name explicitly by setting the @code{name} -frame property. - - Normally you don't specify the name explicitly, and Emacs computes the -frame name automatically based on a template stored in the variable -@code{frame-title-format}. Emacs recomputes the name each time the -frame is redisplayed. - -@defvar frame-title-format -This variable specifies how to compute a name for a frame when you have -not explicitly specified one. The variable's value is actually a mode -line construct, just like @code{mode-line-format}, except that the -@samp{%c} and @samp{%l} constructs are ignored. @xref{Mode Line -Data}. -@end defvar - -@defvar icon-title-format -This variable specifies how to compute the name for an iconified frame, -when you have not explicitly specified the frame title. This title -appears in the icon itself. -@end defvar - -@defvar multiple-frames -This variable is set automatically by Emacs. Its value is @code{t} when -there are two or more frames (not counting minibuffer-only frames or -invisible frames). The default value of @code{frame-title-format} uses -@code{multiple-frames} so as to put the buffer name in the frame title -only when there is more than one frame. - -The value of this variable is not guaranteed to be accurate except -while processing @code{frame-title-format} or -@code{icon-title-format}. -@end defvar - -@node Deleting Frames -@section Deleting Frames -@cindex deleting frames - -Frames remain potentially visible until you explicitly @dfn{delete} -them. A deleted frame cannot appear on the screen, but continues to -exist as a Lisp object until there are no references to it. - -@deffn Command delete-frame &optional frame force -@vindex delete-frame-functions -This function deletes the frame @var{frame}. Unless @var{frame} is a -tooltip, it first runs the hook @code{delete-frame-functions} (each -function gets one argument, @var{frame}). By default, @var{frame} is -the selected frame. - -A frame cannot be deleted if its minibuffer is used by other frames. -Normally, you cannot delete a frame if all other frames are invisible, -but if the @var{force} is non-@code{nil}, then you are allowed to do so. -@end deffn - -@defun frame-live-p frame -The function @code{frame-live-p} returns non-@code{nil} if the frame -@var{frame} has not been deleted. The possible non-@code{nil} return -values are like those of @code{framep}. @xref{Frames}. -@end defun - - Some window managers provide a command to delete a window. These work -by sending a special message to the program that operates the window. -When Emacs gets one of these commands, it generates a -@code{delete-frame} event, whose normal definition is a command that -calls the function @code{delete-frame}. @xref{Misc Events}. - -@node Finding All Frames -@section Finding All Frames -@cindex frames, scanning all - -@defun frame-list -The function @code{frame-list} returns a list of all the frames that -have not been deleted. It is analogous to @code{buffer-list} for -buffers, and includes frames on all terminals. The list that you get is -newly created, so modifying the list doesn't have any effect on the -internals of Emacs. -@end defun - -@defun visible-frame-list -This function returns a list of just the currently visible frames. -@xref{Visibility of Frames}. (Terminal frames always count as -``visible,'' even though only the selected one is actually displayed.) -@end defun - -@defun next-frame &optional frame minibuf -The function @code{next-frame} lets you cycle conveniently through all -the frames on the current display from an arbitrary starting point. It -returns the ``next'' frame after @var{frame} in the cycle. If -@var{frame} is omitted or @code{nil}, it defaults to the selected frame -(@pxref{Input Focus}). - -The second argument, @var{minibuf}, says which frames to consider: - -@table @asis -@item @code{nil} -Exclude minibuffer-only frames. -@item @code{visible} -Consider all visible frames. -@item 0 -Consider all visible or iconified frames. -@item a window -Consider only the frames using that particular window as their -minibuffer. -@item anything else -Consider all frames. -@end table -@end defun - -@defun previous-frame &optional frame minibuf -Like @code{next-frame}, but cycles through all frames in the opposite -direction. -@end defun - - See also @code{next-window} and @code{previous-window}, in @ref{Cyclic -Window Ordering}. - -@node Frames and Windows -@section Frames and Windows - - Each window is part of one and only one frame; you can get the frame -with @code{window-frame}. - -@defun window-frame window -This function returns the frame that @var{window} is on. -@end defun - - All the non-minibuffer windows in a frame are arranged in a cyclic -order. The order runs from the frame's top window, which is at the -upper left corner, down and to the right, until it reaches the window at -the lower right corner (always the minibuffer window, if the frame has -one), and then it moves back to the top. @xref{Cyclic Window Ordering}. - -@defun frame-first-window &optional frame -This returns the topmost, leftmost window of frame @var{frame}. -If omitted or @code{nil}, @var{frame} defaults to the selected frame. -@end defun - -At any time, exactly one window on any frame is @dfn{selected within the -frame}. The significance of this designation is that selecting the -frame also selects this window. You can get the frame's current -selected window with @code{frame-selected-window}. - -@defun frame-selected-window &optional frame -This function returns the window on @var{frame} that is selected -within @var{frame}. If omitted or @code{nil}, @var{frame} defaults to -the selected frame. -@end defun - -@defun set-frame-selected-window frame window -This sets the selected window of frame @var{frame} to @var{window}. -If @var{frame} is @code{nil}, it operates on the selected frame. If -@var{frame} is the selected frame, this makes @var{window} the -selected window. This function returns @var{window}. -@end defun - - Conversely, selecting a window for Emacs with @code{select-window} also -makes that window selected within its frame. @xref{Selecting Windows}. - - Another function that (usually) returns one of the windows in a given -frame is @code{minibuffer-window}. @xref{Definition of minibuffer-window}. - -@node Minibuffers and Frames -@section Minibuffers and Frames - -Normally, each frame has its own minibuffer window at the bottom, which -is used whenever that frame is selected. If the frame has a minibuffer, -you can get it with @code{minibuffer-window} (@pxref{Definition of -minibuffer-window}). - -However, you can also create a frame with no minibuffer. Such a frame -must use the minibuffer window of some other frame. When you create the -frame, you can specify explicitly the minibuffer window to use (in some -other frame). If you don't, then the minibuffer is found in the frame -which is the value of the variable @code{default-minibuffer-frame}. Its -value should be a frame that does have a minibuffer. - -If you use a minibuffer-only frame, you might want that frame to raise -when you enter the minibuffer. If so, set the variable -@code{minibuffer-auto-raise} to @code{t}. @xref{Raising and Lowering}. - -@defvar default-minibuffer-frame -This variable specifies the frame to use for the minibuffer window, by -default. It does not affect existing frames. It is always local to -the current terminal and cannot be buffer-local. @xref{Multiple -Displays}. -@end defvar - -@node Input Focus -@section Input Focus -@cindex input focus -@c @cindex selected frame Duplicates selected-frame - -At any time, one frame in Emacs is the @dfn{selected frame}. The selected -window always resides on the selected frame. - -When Emacs displays its frames on several terminals (@pxref{Multiple -Displays}), each terminal has its own selected frame. But only one of -these is ``@emph{the} selected frame'': it's the frame that belongs to -the terminal from which the most recent input came. That is, when Emacs -runs a command that came from a certain terminal, the selected frame is -the one of that terminal. Since Emacs runs only a single command at any -given time, it needs to consider only one selected frame at a time; this -frame is what we call @dfn{the selected frame} in this manual. The -display on which the selected frame is displayed is the @dfn{selected -frame's display}. - -@defun selected-frame -This function returns the selected frame. -@end defun - -Some window systems and window managers direct keyboard input to the -window object that the mouse is in; others require explicit clicks or -commands to @dfn{shift the focus} to various window objects. Either -way, Emacs automatically keeps track of which frame has the focus. To -switch to a different frame from a Lisp function, call -@code{select-frame-set-input-focus}. - -Lisp programs can also switch frames ``temporarily'' by calling the -function @code{select-frame}. This does not alter the window system's -concept of focus; rather, it escapes from the window manager's control -until that control is somehow reasserted. - -When using a text-only terminal, only one frame can be displayed at a -time on the terminal, so after a call to @code{select-frame}, the next -redisplay actually displays the newly selected frame. This frame -remains selected until a subsequent call to @code{select-frame} or -@code{select-frame-set-input-focus}. Each terminal frame has a number -which appears in the mode line before the buffer name (@pxref{Mode -Line Variables}). - -@defun select-frame-set-input-focus frame -This function makes @var{frame} the selected frame, raises it (should -it happen to be obscured by other frames) and tries to give it the X -server's focus. On a text-only terminal, the next redisplay displays -the new frame on the entire terminal screen. The return value of this -function is not significant. -@end defun - -@c ??? This is not yet implemented properly. -@defun select-frame frame -This function selects frame @var{frame}, temporarily disregarding the -focus of the X server if any. The selection of @var{frame} lasts until -the next time the user does something to select a different frame, or -until the next time this function is called. (If you are using a -window system, the previously selected frame may be restored as the -selected frame after return to the command loop, because it still may -have the window system's input focus.) The specified @var{frame} -becomes the selected frame, as explained above, and the terminal that -@var{frame} is on becomes the selected terminal. This function -returns @var{frame}, or @code{nil} if @var{frame} has been deleted. - -In general, you should never use @code{select-frame} in a way that could -switch to a different terminal without switching back when you're done. -@end defun - -Emacs cooperates with the window system by arranging to select frames as -the server and window manager request. It does so by generating a -special kind of input event, called a @dfn{focus} event, when -appropriate. The command loop handles a focus event by calling -@code{handle-switch-frame}. @xref{Focus Events}. - -@deffn Command handle-switch-frame frame -This function handles a focus event by selecting frame @var{frame}. - -Focus events normally do their job by invoking this command. -Don't call it for any other reason. -@end deffn - -@defun redirect-frame-focus frame &optional focus-frame -This function redirects focus from @var{frame} to @var{focus-frame}. -This means that @var{focus-frame} will receive subsequent keystrokes and -events intended for @var{frame}. After such an event, the value of -@code{last-event-frame} will be @var{focus-frame}. Also, switch-frame -events specifying @var{frame} will instead select @var{focus-frame}. - -If @var{focus-frame} is omitted or @code{nil}, that cancels any existing -redirection for @var{frame}, which therefore once again receives its own -events. - -One use of focus redirection is for frames that don't have minibuffers. -These frames use minibuffers on other frames. Activating a minibuffer -on another frame redirects focus to that frame. This puts the focus on -the minibuffer's frame, where it belongs, even though the mouse remains -in the frame that activated the minibuffer. - -Selecting a frame can also change focus redirections. Selecting frame -@code{bar}, when @code{foo} had been selected, changes any redirections -pointing to @code{foo} so that they point to @code{bar} instead. This -allows focus redirection to work properly when the user switches from -one frame to another using @code{select-window}. - -This means that a frame whose focus is redirected to itself is treated -differently from a frame whose focus is not redirected. -@code{select-frame} affects the former but not the latter. - -The redirection lasts until @code{redirect-frame-focus} is called to -change it. -@end defun - -@defopt focus-follows-mouse -This option is how you inform Emacs whether the window manager transfers -focus when the user moves the mouse. Non-@code{nil} says that it does. -When this is so, the command @code{other-frame} moves the mouse to a -position consistent with the new selected frame. (This option has no -effect on MS-Windows, where the mouse pointer is always automatically -moved by the OS to the selected frame.) -@end defopt - -@node Visibility of Frames -@section Visibility of Frames -@cindex visible frame -@cindex invisible frame -@cindex iconified frame -@cindex frame visibility - -A window frame may be @dfn{visible}, @dfn{invisible}, or -@dfn{iconified}. If it is visible, you can see its contents, unless -other windows cover it. If it is iconified, the frame's contents do -not appear on the screen, but an icon does. If the frame is -invisible, it doesn't show on the screen, not even as an icon. - -Visibility is meaningless for terminal frames, since only the selected -one is actually displayed in any case. - -@deffn Command make-frame-visible &optional frame -This function makes frame @var{frame} visible. If you omit -@var{frame}, it makes the selected frame visible. This does not raise -the frame, but you can do that with @code{raise-frame} if you wish -(@pxref{Raising and Lowering}). -@end deffn - -@deffn Command make-frame-invisible &optional frame force -This function makes frame @var{frame} invisible. If you omit -@var{frame}, it makes the selected frame invisible. - -Unless @var{force} is non-@code{nil}, this function refuses to make -@var{frame} invisible if all other frames are invisible.. -@end deffn - -@deffn Command iconify-frame &optional frame -This function iconifies frame @var{frame}. If you omit @var{frame}, it -iconifies the selected frame. -@end deffn - -@defun frame-visible-p frame -This returns the visibility status of frame @var{frame}. The value is -@code{t} if @var{frame} is visible, @code{nil} if it is invisible, and -@code{icon} if it is iconified. - -On a text-only terminal, all frames are considered visible, whether -they are currently being displayed or not, and this function returns -@code{t} for all frames. -@end defun - - The visibility status of a frame is also available as a frame -parameter. You can read or change it as such. @xref{Management -Parameters}. - - The user can iconify and deiconify frames with the window manager. -This happens below the level at which Emacs can exert any control, but -Emacs does provide events that you can use to keep track of such -changes. @xref{Misc Events}. - -@node Raising and Lowering -@section Raising and Lowering Frames - - Most window systems use a desktop metaphor. Part of this metaphor is -the idea that windows are stacked in a notional third dimension -perpendicular to the screen surface, and thus ordered from ``highest'' -to ``lowest.'' Where two windows overlap, the one higher up covers -the one underneath. Even a window at the bottom of the stack can be -seen if no other window overlaps it. - -@c @cindex raising a frame redundant with raise-frame -@cindex lowering a frame - A window's place in this ordering is not fixed; in fact, users tend -to change the order frequently. @dfn{Raising} a window means moving -it ``up,'' to the top of the stack. @dfn{Lowering} a window means -moving it to the bottom of the stack. This motion is in the notional -third dimension only, and does not change the position of the window -on the screen. - - You can raise and lower Emacs frame Windows with these functions: - -@deffn Command raise-frame &optional frame -This function raises frame @var{frame} (default, the selected frame). -If @var{frame} is invisible or iconified, this makes it visible. -@end deffn - -@deffn Command lower-frame &optional frame -This function lowers frame @var{frame} (default, the selected frame). -@end deffn - -@defopt minibuffer-auto-raise -If this is non-@code{nil}, activation of the minibuffer raises the frame -that the minibuffer window is in. -@end defopt - -You can also enable auto-raise (raising automatically when a frame is -selected) or auto-lower (lowering automatically when it is deselected) -for any frame using frame parameters. @xref{Management Parameters}. - -@node Frame Configurations -@section Frame Configurations -@cindex frame configuration - - A @dfn{frame configuration} records the current arrangement of frames, -all their properties, and the window configuration of each one. -(@xref{Window Configurations}.) - -@defun current-frame-configuration -This function returns a frame configuration list that describes -the current arrangement of frames and their contents. -@end defun - -@defun set-frame-configuration configuration &optional nodelete -This function restores the state of frames described in -@var{configuration}. However, this function does not restore deleted -frames. - -Ordinarily, this function deletes all existing frames not listed in -@var{configuration}. But if @var{nodelete} is non-@code{nil}, the -unwanted frames are iconified instead. -@end defun - -@node Mouse Tracking -@section Mouse Tracking -@cindex mouse tracking -@c @cindex tracking the mouse Duplicates track-mouse - - Sometimes it is useful to @dfn{track} the mouse, which means to display -something to indicate where the mouse is and move the indicator as the -mouse moves. For efficient mouse tracking, you need a way to wait until -the mouse actually moves. - - The convenient way to track the mouse is to ask for events to represent -mouse motion. Then you can wait for motion by waiting for an event. In -addition, you can easily handle any other sorts of events that may -occur. That is useful, because normally you don't want to track the -mouse forever---only until some other event, such as the release of a -button. - -@defspec track-mouse body@dots{} -This special form executes @var{body}, with generation of mouse motion -events enabled. Typically @var{body} would use @code{read-event} to -read the motion events and modify the display accordingly. @xref{Motion -Events}, for the format of mouse motion events. - -The value of @code{track-mouse} is that of the last form in @var{body}. -You should design @var{body} to return when it sees the up-event that -indicates the release of the button, or whatever kind of event means -it is time to stop tracking. -@end defspec - -The usual purpose of tracking mouse motion is to indicate on the screen -the consequences of pushing or releasing a button at the current -position. - -In many cases, you can avoid the need to track the mouse by using -the @code{mouse-face} text property (@pxref{Special Properties}). -That works at a much lower level and runs more smoothly than -Lisp-level mouse tracking. - -@ignore -@c These are not implemented yet. - -These functions change the screen appearance instantaneously. The -effect is transient, only until the next ordinary Emacs redisplay. That -is OK for mouse tracking, since it doesn't make sense for mouse tracking -to change the text, and the body of @code{track-mouse} normally reads -the events itself and does not do redisplay. - -@defun x-contour-region window beg end -This function draws lines to make a box around the text from @var{beg} -to @var{end}, in window @var{window}. -@end defun - -@defun x-uncontour-region window beg end -This function erases the lines that would make a box around the text -from @var{beg} to @var{end}, in window @var{window}. Use it to remove -a contour that you previously made by calling @code{x-contour-region}. -@end defun - -@defun x-draw-rectangle frame left top right bottom -This function draws a hollow rectangle on frame @var{frame} with the -specified edge coordinates, all measured in pixels from the inside top -left corner. It uses the cursor color, the one used for indicating the -location of point. -@end defun - -@defun x-erase-rectangle frame left top right bottom -This function erases a hollow rectangle on frame @var{frame} with the -specified edge coordinates, all measured in pixels from the inside top -left corner. Erasure means redrawing the text and background that -normally belong in the specified rectangle. -@end defun -@end ignore - -@node Mouse Position -@section Mouse Position -@cindex mouse position -@cindex position of mouse - - The functions @code{mouse-position} and @code{set-mouse-position} -give access to the current position of the mouse. - -@defun mouse-position -This function returns a description of the position of the mouse. The -value looks like @code{(@var{frame} @var{x} . @var{y})}, where @var{x} -and @var{y} are integers giving the position in characters relative to -the top left corner of the inside of @var{frame}. -@end defun - -@defvar mouse-position-function -If non-@code{nil}, the value of this variable is a function for -@code{mouse-position} to call. @code{mouse-position} calls this -function just before returning, with its normal return value as the -sole argument, and it returns whatever this function returns to it. - -This abnormal hook exists for the benefit of packages like -@file{xt-mouse.el} that need to do mouse handling at the Lisp level. -@end defvar - -@defun set-mouse-position frame x y -This function @dfn{warps the mouse} to position @var{x}, @var{y} in -frame @var{frame}. The arguments @var{x} and @var{y} are integers, -giving the position in characters relative to the top left corner of the -inside of @var{frame}. If @var{frame} is not visible, this function -does nothing. The return value is not significant. -@end defun - -@defun mouse-pixel-position -This function is like @code{mouse-position} except that it returns -coordinates in units of pixels rather than units of characters. -@end defun - -@defun set-mouse-pixel-position frame x y -This function warps the mouse like @code{set-mouse-position} except that -@var{x} and @var{y} are in units of pixels rather than units of -characters. These coordinates are not required to be within the frame. - -If @var{frame} is not visible, this function does nothing. The return -value is not significant. -@end defun - -@need 3000 - -@node Pop-Up Menus -@section Pop-Up Menus - - When using a window system, a Lisp program can pop up a menu so that -the user can choose an alternative with the mouse. - -@defun x-popup-menu position menu -This function displays a pop-up menu and returns an indication of -what selection the user makes. - -The argument @var{position} specifies where on the screen to put the -top left corner of the menu. It can be either a mouse button event -(which says to put the menu where the user actuated the button) or a -list of this form: - -@example -((@var{xoffset} @var{yoffset}) @var{window}) -@end example - -@noindent -where @var{xoffset} and @var{yoffset} are coordinates, measured in -pixels, counting from the top left corner of @var{window}. @var{window} -may be a window or a frame. - -If @var{position} is @code{t}, it means to use the current mouse -position. If @var{position} is @code{nil}, it means to precompute the -key binding equivalents for the keymaps specified in @var{menu}, -without actually displaying or popping up the menu. - -The argument @var{menu} says what to display in the menu. It can be a -keymap or a list of keymaps (@pxref{Menu Keymaps}). In this case, the -return value is the list of events corresponding to the user's choice. -(This list has more than one element if the choice occurred in a -submenu.) Note that @code{x-popup-menu} does not actually execute the -command bound to that sequence of events. - -Alternatively, @var{menu} can have the following form: - -@example -(@var{title} @var{pane1} @var{pane2}...) -@end example - -@noindent -where each pane is a list of form - -@example -(@var{title} @var{item1} @var{item2}...) -@end example - -Each item should normally be a cons cell @code{(@var{line} . @var{value})}, -where @var{line} is a string, and @var{value} is the value to return if -that @var{line} is chosen. An item can also be a string; this makes a -non-selectable line in the menu. - -If the user gets rid of the menu without making a valid choice, for -instance by clicking the mouse away from a valid choice or by typing -keyboard input, then this normally results in a quit and -@code{x-popup-menu} does not return. But if @var{position} is a mouse -button event (indicating that the user invoked the menu with the -mouse) then no quit occurs and @code{x-popup-menu} returns @code{nil}. -@end defun - - @strong{Usage note:} Don't use @code{x-popup-menu} to display a menu -if you could do the job with a prefix key defined with a menu keymap. -If you use a menu keymap to implement a menu, @kbd{C-h c} and @kbd{C-h -a} can see the individual items in that menu and provide help for them. -If instead you implement the menu by defining a command that calls -@code{x-popup-menu}, the help facilities cannot know what happens inside -that command, so they cannot give any help for the menu's items. - - The menu bar mechanism, which lets you switch between submenus by -moving the mouse, cannot look within the definition of a command to see -that it calls @code{x-popup-menu}. Therefore, if you try to implement a -submenu using @code{x-popup-menu}, it cannot work with the menu bar in -an integrated fashion. This is why all menu bar submenus are -implemented with menu keymaps within the parent menu, and never with -@code{x-popup-menu}. @xref{Menu Bar}. - - If you want a menu bar submenu to have contents that vary, you should -still use a menu keymap to implement it. To make the contents vary, add -a hook function to @code{menu-bar-update-hook} to update the contents of -the menu keymap as necessary. - -@node Dialog Boxes -@section Dialog Boxes -@cindex dialog boxes - - A dialog box is a variant of a pop-up menu---it looks a little -different, it always appears in the center of a frame, and it has just -one level and one or more buttons. The main use of dialog boxes is -for asking questions that the user can answer with ``yes,'' ``no,'' -and a few other alternatives. With a single button, they can also -force the user to acknowledge important information. The functions -@code{y-or-n-p} and @code{yes-or-no-p} use dialog boxes instead of the -keyboard, when called from commands invoked by mouse clicks. - -@defun x-popup-dialog position contents &optional header -This function displays a pop-up dialog box and returns an indication of -what selection the user makes. The argument @var{contents} specifies -the alternatives to offer; it has this format: - -@example -(@var{title} (@var{string} . @var{value})@dots{}) -@end example - -@noindent -which looks like the list that specifies a single pane for -@code{x-popup-menu}. - -The return value is @var{value} from the chosen alternative. - -As for @code{x-popup-menu}, an element of the list may be just a -string instead of a cons cell @code{(@var{string} . @var{value})}. -That makes a box that cannot be selected. - -If @code{nil} appears in the list, it separates the left-hand items from -the right-hand items; items that precede the @code{nil} appear on the -left, and items that follow the @code{nil} appear on the right. If you -don't include a @code{nil} in the list, then approximately half the -items appear on each side. - -Dialog boxes always appear in the center of a frame; the argument -@var{position} specifies which frame. The possible values are as in -@code{x-popup-menu}, but the precise coordinates or the individual -window don't matter; only the frame matters. - -If @var{header} is non-@code{nil}, the frame title for the box is -@samp{Information}, otherwise it is @samp{Question}. The former is used -for @code{message-box} (@pxref{message-box}). - -In some configurations, Emacs cannot display a real dialog box; so -instead it displays the same items in a pop-up menu in the center of the -frame. - -If the user gets rid of the dialog box without making a valid choice, -for instance using the window manager, then this produces a quit and -@code{x-popup-dialog} does not return. -@end defun - -@node Pointer Shape -@section Pointer Shape -@cindex pointer shape -@cindex mouse pointer shape - - You can specify the mouse pointer style for particular text or -images using the @code{pointer} text property, and for images with the -@code{:pointer} and @code{:map} image properties. The values you can -use in these properties are @code{text} (or @code{nil}), @code{arrow}, -@code{hand}, @code{vdrag}, @code{hdrag}, @code{modeline}, and -@code{hourglass}. @code{text} stands for the usual mouse pointer -style used over text. - - Over void parts of the window (parts that do not correspond to any -of the buffer contents), the mouse pointer usually uses the -@code{arrow} style, but you can specify a different style (one of -those above) by setting @code{void-text-area-pointer}. - -@defvar void-text-area-pointer -This variable specifies the mouse pointer style for void text areas. -These include the areas after the end of a line or below the last line -in the buffer. The default is to use the @code{arrow} (non-text) -pointer style. -@end defvar - - You can specify what the @code{text} pointer style really looks like -by setting the variable @code{x-pointer-shape}. - -@defvar x-pointer-shape -This variable specifies the pointer shape to use ordinarily in the -Emacs frame, for the @code{text} pointer style. -@end defvar - -@defvar x-sensitive-text-pointer-shape -This variable specifies the pointer shape to use when the mouse -is over mouse-sensitive text. -@end defvar - - These variables affect newly created frames. They do not normally -affect existing frames; however, if you set the mouse color of a -frame, that also installs the current value of those two variables. -@xref{Color Parameters}. - - The values you can use, to specify either of these pointer shapes, are -defined in the file @file{lisp/term/x-win.el}. Use @kbd{M-x apropos -@key{RET} x-pointer @key{RET}} to see a list of them. - -@node Window System Selections -@section Window System Selections -@cindex selection (for window systems) - -The X server records a set of @dfn{selections} which permit transfer of -data between application programs. The various selections are -distinguished by @dfn{selection types}, represented in Emacs by -symbols. X clients including Emacs can read or set the selection for -any given type. - -@deffn Command x-set-selection type data -This function sets a ``selection'' in the X server. It takes two -arguments: a selection type @var{type}, and the value to assign to it, -@var{data}. If @var{data} is @code{nil}, it means to clear out the -selection. Otherwise, @var{data} may be a string, a symbol, an integer -(or a cons of two integers or list of two integers), an overlay, or a -cons of two markers pointing to the same buffer. An overlay or a pair -of markers stands for text in the overlay or between the markers. - -The argument @var{data} may also be a vector of valid non-vector -selection values. - -Each possible @var{type} has its own selection value, which changes -independently. The usual values of @var{type} are @code{PRIMARY}, -@code{SECONDARY} and @code{CLIPBOARD}; these are symbols with upper-case -names, in accord with X Window System conventions. If @var{type} is -@code{nil}, that stands for @code{PRIMARY}. - -This function returns @var{data}. -@end deffn - -@defun x-get-selection &optional type data-type -This function accesses selections set up by Emacs or by other X -clients. It takes two optional arguments, @var{type} and -@var{data-type}. The default for @var{type}, the selection type, is -@code{PRIMARY}. - -The @var{data-type} argument specifies the form of data conversion to -use, to convert the raw data obtained from another X client into Lisp -data. Meaningful values include @code{TEXT}, @code{STRING}, -@code{UTF8_STRING}, @code{TARGETS}, @code{LENGTH}, @code{DELETE}, -@code{FILE_NAME}, @code{CHARACTER_POSITION}, @code{NAME}, -@code{LINE_NUMBER}, @code{COLUMN_NUMBER}, @code{OWNER_OS}, -@code{HOST_NAME}, @code{USER}, @code{CLASS}, @code{ATOM}, and -@code{INTEGER}. (These are symbols with upper-case names in accord -with X conventions.) The default for @var{data-type} is -@code{STRING}. -@end defun - -@cindex cut buffer -The X server also has a set of eight numbered @dfn{cut buffers} which can -store text or other data being moved between applications. Cut buffers -are considered obsolete, but Emacs supports them for the sake of X -clients that still use them. Cut buffers are numbered from 0 to 7. - -@defun x-get-cut-buffer &optional n -This function returns the contents of cut buffer number @var{n}. -If omitted @var{n} defaults to 0. -@end defun - -@defun x-set-cut-buffer string &optional push -@anchor{Definition of x-set-cut-buffer} -This function stores @var{string} into the first cut buffer (cut buffer -0). If @var{push} is @code{nil}, only the first cut buffer is changed. -If @var{push} is non-@code{nil}, that says to move the values down -through the series of cut buffers, much like the way successive kills in -Emacs move down the kill ring. In other words, the previous value of -the first cut buffer moves into the second cut buffer, and the second to -the third, and so on through all eight cut buffers. -@end defun - -@defvar selection-coding-system -This variable specifies the coding system to use when reading and -writing selections or the clipboard. @xref{Coding -Systems}. The default is @code{compound-text-with-extensions}, which -converts to the text representation that X11 normally uses. -@end defvar - -@cindex clipboard support (for MS-Windows) -When Emacs runs on MS-Windows, it does not implement X selections in -general, but it does support the clipboard. @code{x-get-selection} -and @code{x-set-selection} on MS-Windows support the text data type -only; if the clipboard holds other types of data, Emacs treats the -clipboard as empty. - -@cindex scrap support (for Mac OS) -On Mac OS, selection-like data transfer between applications is -performed through a mechanism called @dfn{scraps}. The clipboard is a -particular scrap named @code{com.apple.scrap.clipboard}. Types of scrap -data are called @dfn{scrap flavor types}, which are identified by -four-char codes such as @code{TEXT}. Emacs associates a selection with -a scrap, and a selection type with a scrap flavor type via -@code{mac-scrap-name} and @code{mac-ostype} properties, respectively. - -@example -(get 'CLIPBOARD 'mac-scrap-name) - @result{} "com.apple.scrap.clipboard" -(get 'com.apple.traditional-mac-plain-text 'mac-ostype) - @result{} "TEXT" -@end example - -Conventionally, selection types for scrap flavor types on Mac OS have -the form of @acronym{UTI, Uniform Type Identifier} such as -@code{com.apple.traditional-mac-plain-text}, -@code{public.utf16-plain-text}, and @code{public.file-url}. - -@defopt x-select-enable-clipboard -If this is non-@code{nil}, the Emacs yank functions consult the -clipboard before the primary selection, and the kill functions store in -the clipboard as well as the primary selection. Otherwise they do not -access the clipboard at all. The default is @code{nil} on most systems, -but @code{t} on MS-Windows and Mac. -@end defopt - -@node Drag and Drop -@section Drag and Drop - -@vindex x-dnd-test-function -@vindex x-dnd-known-types - When a user drags something from another application over Emacs, that other -application expects Emacs to tell it if Emacs can handle the data that is -dragged. The variable @code{x-dnd-test-function} is used by Emacs to determine -what to reply. The default value is @code{x-dnd-default-test-function} -which accepts drops if the type of the data to be dropped is present in -@code{x-dnd-known-types}. You can customize @code{x-dnd-test-function} and/or -@code{x-dnd-known-types} if you want Emacs to accept or reject drops based -on some other criteria. - -@vindex x-dnd-types-alist - If you want to change the way Emacs handles drop of different types -or add a new type, customize @code{x-dnd-types-alist}. This requires -detailed knowledge of what types other applications use for drag and -drop. - -@vindex dnd-protocol-alist - When an URL is dropped on Emacs it may be a file, but it may also be -another URL type (ftp, http, etc.). Emacs first checks -@code{dnd-protocol-alist} to determine what to do with the URL. If -there is no match there and if @code{browse-url-browser-function} is -an alist, Emacs looks for a match there. If no match is found the -text for the URL is inserted. If you want to alter Emacs behavior, -you can customize these variables. - -@node Color Names -@section Color Names - -@cindex color names -@cindex specify color -@cindex numerical RGB color specification - A color name is text (usually in a string) that specifies a color. -Symbolic names such as @samp{black}, @samp{white}, @samp{red}, etc., -are allowed; use @kbd{M-x list-colors-display} to see a list of -defined names. You can also specify colors numerically in forms such -as @samp{#@var{rgb}} and @samp{RGB:@var{r}/@var{g}/@var{b}}, where -@var{r} specifies the red level, @var{g} specifies the green level, -and @var{b} specifies the blue level. You can use either one, two, -three, or four hex digits for @var{r}; then you must use the same -number of hex digits for all @var{g} and @var{b} as well, making -either 3, 6, 9 or 12 hex digits in all. (See the documentation of the -X Window System for more details about numerical RGB specification of -colors.) - - These functions provide a way to determine which color names are -valid, and what they look like. In some cases, the value depends on the -@dfn{selected frame}, as described below; see @ref{Input Focus}, for the -meaning of the term ``selected frame.'' - -@defun color-defined-p color &optional frame -This function reports whether a color name is meaningful. It returns -@code{t} if so; otherwise, @code{nil}. The argument @var{frame} says -which frame's display to ask about; if @var{frame} is omitted or -@code{nil}, the selected frame is used. - -Note that this does not tell you whether the display you are using -really supports that color. When using X, you can ask for any defined -color on any kind of display, and you will get some result---typically, -the closest it can do. To determine whether a frame can really display -a certain color, use @code{color-supported-p} (see below). - -@findex x-color-defined-p -This function used to be called @code{x-color-defined-p}, -and that name is still supported as an alias. -@end defun - -@defun defined-colors &optional frame -This function returns a list of the color names that are defined -and supported on frame @var{frame} (default, the selected frame). -If @var{frame} does not support colors, the value is @code{nil}. - -@findex x-defined-colors -This function used to be called @code{x-defined-colors}, -and that name is still supported as an alias. -@end defun - -@defun color-supported-p color &optional frame background-p -This returns @code{t} if @var{frame} can really display the color -@var{color} (or at least something close to it). If @var{frame} is -omitted or @code{nil}, the question applies to the selected frame. - -Some terminals support a different set of colors for foreground and -background. If @var{background-p} is non-@code{nil}, that means you are -asking whether @var{color} can be used as a background; otherwise you -are asking whether it can be used as a foreground. - -The argument @var{color} must be a valid color name. -@end defun - -@defun color-gray-p color &optional frame -This returns @code{t} if @var{color} is a shade of gray, as defined on -@var{frame}'s display. If @var{frame} is omitted or @code{nil}, the -question applies to the selected frame. If @var{color} is not a valid -color name, this function returns @code{nil}. -@end defun - -@defun color-values color &optional frame -@cindex rgb value -This function returns a value that describes what @var{color} should -ideally look like on @var{frame}. If @var{color} is defined, the -value is a list of three integers, which give the amount of red, the -amount of green, and the amount of blue. Each integer ranges in -principle from 0 to 65535, but some displays may not use the full -range. This three-element list is called the @dfn{rgb values} of the -color. - -If @var{color} is not defined, the value is @code{nil}. - -@example -(color-values "black") - @result{} (0 0 0) -(color-values "white") - @result{} (65280 65280 65280) -(color-values "red") - @result{} (65280 0 0) -(color-values "pink") - @result{} (65280 49152 51968) -(color-values "hungry") - @result{} nil -@end example - -The color values are returned for @var{frame}'s display. If -@var{frame} is omitted or @code{nil}, the information is returned for -the selected frame's display. If the frame cannot display colors, the -value is @code{nil}. - -@findex x-color-values -This function used to be called @code{x-color-values}, -and that name is still supported as an alias. -@end defun - -@node Text Terminal Colors -@section Text Terminal Colors -@cindex colors on text-only terminals - - Text-only terminals usually support only a small number of colors, -and the computer uses small integers to select colors on the terminal. -This means that the computer cannot reliably tell what the selected -color looks like; instead, you have to inform your application which -small integers correspond to which colors. However, Emacs does know -the standard set of colors and will try to use them automatically. - - The functions described in this section control how terminal colors -are used by Emacs. - - Several of these functions use or return @dfn{rgb values}, described -in @ref{Color Names}. - - These functions accept a display (either a frame or the name of a -terminal) as an optional argument. We hope in the future to make Emacs -support more than one text-only terminal at one time; then this argument -will specify which terminal to operate on (the default being the -selected frame's terminal; @pxref{Input Focus}). At present, though, -the @var{frame} argument has no effect. - -@defun tty-color-define name number &optional rgb frame -This function associates the color name @var{name} with -color number @var{number} on the terminal. - -The optional argument @var{rgb}, if specified, is an rgb value, a list -of three numbers that specify what the color actually looks like. -If you do not specify @var{rgb}, then this color cannot be used by -@code{tty-color-approximate} to approximate other colors, because -Emacs will not know what it looks like. -@end defun - -@defun tty-color-clear &optional frame -This function clears the table of defined colors for a text-only terminal. -@end defun - -@defun tty-color-alist &optional frame -This function returns an alist recording the known colors supported by a -text-only terminal. - -Each element has the form @code{(@var{name} @var{number} . @var{rgb})} -or @code{(@var{name} @var{number})}. Here, @var{name} is the color -name, @var{number} is the number used to specify it to the terminal. -If present, @var{rgb} is a list of three color values (for red, green, -and blue) that says what the color actually looks like. -@end defun - -@defun tty-color-approximate rgb &optional frame -This function finds the closest color, among the known colors -supported for @var{display}, to that described by the rgb value -@var{rgb} (a list of color values). The return value is an element of -@code{tty-color-alist}. -@end defun - -@defun tty-color-translate color &optional frame -This function finds the closest color to @var{color} among the known -colors supported for @var{display} and returns its index (an integer). -If the name @var{color} is not defined, the value is @code{nil}. -@end defun - -@node Resources -@section X Resources - -@defun x-get-resource attribute class &optional component subclass -The function @code{x-get-resource} retrieves a resource value from the X -Window defaults database. - -Resources are indexed by a combination of a @dfn{key} and a @dfn{class}. -This function searches using a key of the form -@samp{@var{instance}.@var{attribute}} (where @var{instance} is the name -under which Emacs was invoked), and using @samp{Emacs.@var{class}} as -the class. - -The optional arguments @var{component} and @var{subclass} add to the key -and the class, respectively. You must specify both of them or neither. -If you specify them, the key is -@samp{@var{instance}.@var{component}.@var{attribute}}, and the class is -@samp{Emacs.@var{class}.@var{subclass}}. -@end defun - -@defvar x-resource-class -This variable specifies the application name that @code{x-get-resource} -should look up. The default value is @code{"Emacs"}. You can examine X -resources for application names other than ``Emacs'' by binding this -variable to some other string, around a call to @code{x-get-resource}. -@end defvar - -@defvar x-resource-name -This variable specifies the instance name that @code{x-get-resource} -should look up. The default value is the name Emacs was invoked with, -or the value specified with the @samp{-name} or @samp{-rn} switches. -@end defvar - -To illustrate some of the above, suppose that you have the line: - -@example -xterm.vt100.background: yellow -@end example - -@noindent -in your X resources file (whose name is usually @file{~/.Xdefaults} -or @file{~/.Xresources}). Then: - -@example -@group -(let ((x-resource-class "XTerm") (x-resource-name "xterm")) - (x-get-resource "vt100.background" "VT100.Background")) - @result{} "yellow" -@end group -@group -(let ((x-resource-class "XTerm") (x-resource-name "xterm")) - (x-get-resource "background" "VT100" "vt100" "Background")) - @result{} "yellow" -@end group -@end example - - @xref{X Resources,, X Resources, emacs, The GNU Emacs Manual}. - -@node Display Feature Testing -@section Display Feature Testing -@cindex display feature testing - - The functions in this section describe the basic capabilities of a -particular display. Lisp programs can use them to adapt their behavior -to what the display can do. For example, a program that ordinarily uses -a popup menu could use the minibuffer if popup menus are not supported. - - The optional argument @var{display} in these functions specifies which -display to ask the question about. It can be a display name, a frame -(which designates the display that frame is on), or @code{nil} (which -refers to the selected frame's display, @pxref{Input Focus}). - - @xref{Color Names}, @ref{Text Terminal Colors}, for other functions to -obtain information about displays. - -@defun display-popup-menus-p &optional display -This function returns @code{t} if popup menus are supported on -@var{display}, @code{nil} if not. Support for popup menus requires that -the mouse be available, since the user cannot choose menu items without -a mouse. -@end defun - -@defun display-graphic-p &optional display -This function returns @code{t} if @var{display} is a graphic display -capable of displaying several frames and several different fonts at -once. This is true for displays that use a window system such as X, and -false for text-only terminals. -@end defun - -@defun display-mouse-p &optional display -@cindex mouse, availability -This function returns @code{t} if @var{display} has a mouse available, -@code{nil} if not. -@end defun - -@defun display-color-p &optional display -@findex x-display-color-p -This function returns @code{t} if the screen is a color screen. -It used to be called @code{x-display-color-p}, and that name -is still supported as an alias. -@end defun - -@defun display-grayscale-p &optional display -This function returns @code{t} if the screen can display shades of gray. -(All color displays can do this.) -@end defun - -@defun display-supports-face-attributes-p attributes &optional display -@anchor{Display Face Attribute Testing} -This function returns non-@code{nil} if all the face attributes in -@var{attributes} are supported (@pxref{Face Attributes}). - -The definition of `supported' is somewhat heuristic, but basically -means that a face containing all the attributes in @var{attributes}, -when merged with the default face for display, can be represented in a -way that's - -@enumerate -@item -different in appearance than the default face, and - -@item -`close in spirit' to what the attributes specify, if not exact. -@end enumerate - -Point (2) implies that a @code{:weight black} attribute will be -satisfied by any display that can display bold, as will -@code{:foreground "yellow"} as long as some yellowish color can be -displayed, but @code{:slant italic} will @emph{not} be satisfied by -the tty display code's automatic substitution of a `dim' face for -italic. -@end defun - -@defun display-selections-p &optional display -This function returns @code{t} if @var{display} supports selections. -Windowed displays normally support selections, but they may also be -supported in some other cases. -@end defun - -@defun display-images-p &optional display -This function returns @code{t} if @var{display} can display images. -Windowed displays ought in principle to handle images, but some -systems lack the support for that. On a display that does not support -images, Emacs cannot display a tool bar. -@end defun - -@defun display-screens &optional display -This function returns the number of screens associated with the display. -@end defun - -@defun display-pixel-height &optional display -This function returns the height of the screen in pixels. -On a character terminal, it gives the height in characters. - -For graphical terminals, note that on ``multi-monitor'' setups this -refers to the pixel width for all physical monitors associated with -@var{display}. @xref{Multiple Displays}. -@end defun - -@defun display-pixel-width &optional display -This function returns the width of the screen in pixels. -On a character terminal, it gives the width in characters. - -For graphical terminals, note that on ``multi-monitor'' setups this -refers to the pixel width for all physical monitors associated with -@var{display}. @xref{Multiple Displays}. -@end defun - -@defun display-mm-height &optional display -This function returns the height of the screen in millimeters, -or @code{nil} if Emacs cannot get that information. -@end defun - -@defun display-mm-width &optional display -This function returns the width of the screen in millimeters, -or @code{nil} if Emacs cannot get that information. -@end defun - -@defvar display-mm-dimensions-alist -This variable allows the user to specify the dimensions of graphical -displays returned by @code{display-mm-height} and -@code{display-mm-width} in case the system provides incorrect values. -@end defvar - -@defun display-backing-store &optional display -This function returns the backing store capability of the display. -Backing store means recording the pixels of windows (and parts of -windows) that are not exposed, so that when exposed they can be -displayed very quickly. - -Values can be the symbols @code{always}, @code{when-mapped}, or -@code{not-useful}. The function can also return @code{nil} -when the question is inapplicable to a certain kind of display. -@end defun - -@defun display-save-under &optional display -This function returns non-@code{nil} if the display supports the -SaveUnder feature. That feature is used by pop-up windows -to save the pixels they obscure, so that they can pop down -quickly. -@end defun - -@defun display-planes &optional display -This function returns the number of planes the display supports. -This is typically the number of bits per pixel. -For a tty display, it is log to base two of the number of colors supported. -@end defun - -@defun display-visual-class &optional display -This function returns the visual class for the screen. The value is one -of the symbols @code{static-gray}, @code{gray-scale}, -@code{static-color}, @code{pseudo-color}, @code{true-color}, and -@code{direct-color}. -@end defun - -@defun display-color-cells &optional display -This function returns the number of color cells the screen supports. -@end defun - - These functions obtain additional information specifically -about X displays. - -@defun x-server-version &optional display -This function returns the list of version numbers of the X server -running the display. The value is a list of three integers: the major -and minor version numbers of the X protocol, and the -distributor-specific release number of the X server software itself. -@end defun - -@defun x-server-vendor &optional display -This function returns the ``vendor'' that provided the X server -software (as a string). Really this means whoever distributes the X -server. - -When the developers of X labelled software distributors as -``vendors,'' they showed their false assumption that no system could -ever be developed and distributed noncommercially. -@end defun - -@ignore -@defvar x-no-window-manager -This variable's value is @code{t} if no X window manager is in use. -@end defvar -@end ignore - -@ignore -@item -The functions @code{x-pixel-width} and @code{x-pixel-height} return the -width and height of an X Window frame, measured in pixels. -@end ignore - -@ignore - arch-tag: 94977df6-3dca-4730-b57b-c6329e9282ba -@end ignore |