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This is Info file elisp, produced by Makeinfo-1.63 from the input file elisp.texi. This version is the edition 2.4.2 of the GNU Emacs Lisp Reference Manual. It corresponds to Emacs Version 19.34. Published by the Free Software Foundation 59 Temple Place, Suite 330 Boston, MA 02111-1307 USA Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996 Free Software Foundation, Inc. Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that this permission notice may be stated in a translation approved by the Foundation. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided also that the section entitled "GNU General Public License" is included exactly as in the original, and provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that the section entitled "GNU General Public License" may be included in a translation approved by the Free Software Foundation instead of in the original English. File: elisp, Node: Frame Parameters, Next: Frame Titles, Prev: Multiple Displays, Up: Frames 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 for the sake of window systems. A terminal frame has a few parameters, mostly for compatibility's sake; only the height, width and `buffer-predicate' parameters really do something. * Menu: * Parameter Access:: How to change a frame's parameters. * Initial Parameters:: Specifying frame parameters when you make a frame. * X Frame Parameters:: List of frame parameters. * Size and Position:: Changing the size and position of a frame. File: elisp, Node: Parameter Access, Next: Initial Parameters, Up: Frame Parameters Access to Frame Parameters -------------------------- These functions let you read and change the parameter values of a frame. - Function: frame-parameters FRAME The function `frame-parameters' returns an alist listing all the parameters of FRAME and their values. - Function: modify-frame-parameters FRAME ALIST This function alters the parameters of frame FRAME based on the elements of ALIST. Each element of ALIST has the form `(PARM . VALUE)', where PARM is a symbol naming a parameter. If you don't mention a parameter in ALIST, its value doesn't change. File: elisp, Node: Initial Parameters, Next: X Frame Parameters, Prev: Parameter Access, Up: Frame Parameters Initial Frame Parameters ------------------------ You can specify the parameters for the initial startup frame by setting `initial-frame-alist' in your `.emacs' file. - Variable: initial-frame-alist This variable's value is an alist of parameter values used when creating the initial X window frame. You can set this variable to specify the appearance of the initial frame without altering subsequent frames. Each element has the form: (PARAMETER . VALUE) Emacs creates the initial frame before it reads your `~/.emacs' file. After reading that file, Emacs checks `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 affect before the frame is created. *Note X Resources: (emacs)Resources X. 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 `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 `initial-frame-alist' with values that match the X resources. If these parameters specify a separate minibuffer-only frame with `(minibuffer . nil)', and you have not created one, Emacs creates one for you. - Variable: 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. - Variable: default-frame-alist This is an alist specifying default values of frame parameters for all Emacs frames--the first frame, and subsequent frames. In many cases, you can get the same results by means of X resources. See also `special-display-frame-alist', in *Note Choosing Window::. If you use options that specify window appearance when you invoke Emacs, they take effect by adding elements to `default-frame-alist'. One exception is `-geometry', which adds the specified position to `initial-frame-alist' instead. *Note Command Arguments: (emacs)Command Arguments. File: elisp, Node: X Frame Parameters, Next: Size and Position, Prev: Initial Parameters, Up: Frame Parameters X Window Frame Parameters ------------------------- Just what parameters a frame has depends on what display mechanism it uses. Here is a table of the parameters of an X window frame; of these, `name', `height', `width', and `buffer-predicate' provide meaningful information in non-X frames. `name' The name of the frame. Most window managers display the frame's name in the frame's border, at the top of the frame. If you don't specify a name, and you have more than one frame, Emacs sets the frame name based on the buffer displayed in the frame's selected window. 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. `display' The display on which to open this frame. It should be a string of the form `"HOST:DPY.SCREEN"', just like the `DISPLAY' environment variable. `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 POS, or a list of the form `(+ POS)' which permits specifying a negative POS value. A negative number -POS, or a list of the form `(- 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 POS counts toward the left. If the parameter is a negative integer -POS then 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-`nil' value for the `user-position' parameter as well. `top' The screen position of the top edge, in pixels, with respect to the top edge of the screen. The value may be a positive number POS, or a list of the form `(+ POS)' which permits specifying a negative POS value. A negative number -POS, or a list of the form `(- POS)', actually specifies the position of the bottom edge of the window with respect to the bottom edge of the screen. A positive value of POS counts toward the top. If the parameter is a negative integer -POS then 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-`nil' value for the `user-position' parameter as well. `icon-left' The screen position of the left edge *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. `icon-top' The screen position of the top edge *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. `user-position' When you create a frame and specify its screen position with the `left' and `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-`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 `twm', let the user specify whether to obey program-specified positions or ignore them. When you call `make-frame', you should specify a non-`nil' value for this parameter if the values of the `left' and `top' parameters represent the user's stated preference; otherwise, use `nil'. `height' The height of the frame contents, in characters. (To get the height in pixels, call `frame-pixel-height'; see *Note Size and Position::.) `width' The width of the frame contents, in characters. (To get the height in pixels, call `frame-pixel-width'; see *Note Size and Position::.) `window-id' The number of the X window for the frame. `minibuffer' Whether this frame has its own minibuffer. The value `t' means yes, `nil' means no, `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. `buffer-predicate' The buffer-predicate function for this frame. The function `other-buffer' uses this predicate (from the selected frame) to decide which buffers it should consider, if the predicate is not `nil'. It calls the predicate with one arg, a buffer, once for each buffer; if the predicate returns a non-`nil' value, it considers that buffer. `font' The name of the font for displaying text in the frame. This is a string. `auto-raise' Whether selecting the frame raises it (non-`nil' means yes). `auto-lower' Whether deselecting the frame lowers it (non-`nil' means yes). `vertical-scroll-bars' Whether the frame has scroll bars for vertical scrolling (non-`nil' means yes). `horizontal-scroll-bars' Whether the frame has scroll bars for horizontal scrolling (non-`nil' means yes). (Horizontal scroll bars are not currently implemented.) `scroll-bar-width' The width of the vertical scroll bar, in pixels. `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-`nil' value specifies the default bitmap icon (a picture of a gnu); `nil' specifies a text icon. `icon-name' The name to use in the icon for this frame, when and if the icon appears. If this is `nil', the frame's title is used. `foreground-color' The color to use for the image of a character. This is a string; the X server defines the meaningful color names. `background-color' The color to use for the background of characters. `mouse-color' The color for the mouse pointer. `cursor-color' The color for the cursor that shows point. `border-color' The color for the border of the frame. `cursor-type' The way to display the cursor. The legitimate values are `bar', `box', and `(bar . WIDTH)'. The symbol `box' specifies an ordinary black box overlaying the character after point; that is the default. The symbol `bar' specifies a vertical bar between characters as the cursor. `(bar . WIDTH)' specifies a bar WIDTH pixels wide. `border-width' The width in pixels of the window border. `internal-border-width' The distance in pixels between text and border. `unsplittable' If non-`nil', this frame's window is never split automatically. `visibility' The state of visibility of the frame. There are three possibilities: `nil' for invisible, `t' for visible, and `icon' for iconified. *Note Visibility of Frames::. `menu-bar-lines' The number of lines to allocate at the top of the frame for a menu bar. The default is 1. *Note Menu Bar::. (In Emacs versions that use the X toolkit, there is only one menu bar line; all that matters about the number you specify is whether it is greater than zero.) `parent-id' 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.) File: elisp, Node: Size and Position, Prev: X Frame Parameters, Up: Frame Parameters Frame Size And Position ----------------------- You can read or change the size and position of a frame using the frame parameters `left', `top', `height', and `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: - Function: set-frame-position FRAME LEFT TOP This function sets the position of the top left corner of FRAME to LEFT and TOP. These arguments are measured in pixels, and count from the top left corner of the screen. Negative parameter values count up or rightward from the top left corner of the screen. - Function: frame-height &optional FRAME - Function: frame-width &optional FRAME These functions return the height and width of FRAME, measured in characters. If you don't supply FRAME, they use the selected frame. - Function: frame-pixel-height &optional FRAME - Function: frame-pixel-width &optional FRAME These functions return the height and width of FRAME, measured in pixels. If you don't supply FRAME, they use the selected frame. - Function: frame-char-height &optional FRAME - Function: frame-char-width &optional FRAME These functions return the height and width of a character in FRAME, measured in pixels. The values depend on the choice of font. If you don't supply FRAME, these functions use the selected frame. - Function: set-frame-size FRAME COLS ROWS This function sets the size of FRAME, measured in characters; COLS and ROWS specify the new width and height. To set the size based on values measured in pixels, use `frame-char-height' and `frame-char-width' to convert them to units of characters. The old-fashioned functions `set-screen-height' and `set-screen-width', which were used to specify the height and width of the screen in Emacs versions that did not support multiple frames, are still usable. They apply to the selected frame. *Note Screen Size::. - Function: x-parse-geometry GEOM The function `x-parse-geometry' converts a standard X windows geometry string to an alist that you can use as part of the argument to `make-frame'. The alist describes which parameters were specified in GEOM, and gives the values specified for them. Each element looks like `(PARAMETER . VALUE)'. The possible PARAMETER values are `left', `top', `width', and `height'. For the size parameters, the value must be an integer. The position parameter names `left' and `top' are not totally accurate, because some values indicate the position of the right or bottom edges instead. These are the VALUE possibilities for the position parameters: 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. `(+ 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 POSITION may be positive or negative; a negative value specifies a position outside the screen. `(- 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 POSITION may be positive or negative; a negative value specifies a position outside the screen. Here is an example: (x-parse-geometry "35x70+0-0") => ((width . 35) (height . 70) (left . 0) (top - 0)) File: elisp, Node: Frame Titles, Next: Deleting Frames, Prev: Frame Parameters, Up: Frames Frame Titles ============ Every frame has a title; most window managers display the frame title at the top of the frame. You can specify an explicit title with the `name' frame property. But normally you don't specify this explicitly, and Emacs computes the title automatically. Emacs computes the frame title based on a template stored in the variable `frame-title-format'. - Variable: frame-title-format This variable specifies how to compute a title for a frame when you have not explicitly specified one. The variable's value is actually a mode line construct, just like `mode-line-format'. *Note Mode Line Data::. - Variable: icon-title-format This variable specifies how to compute the title for an iconified frame, when you have not explicitly specified the frame title. This title appears in the icon itself. - Variable: multiple-frames This variable is set automatically by Emacs. Its value is `t' when there are two or more frames (not counting minibuffer-only frames or invisible frames). The default value of `frame-title-format' uses `multiple-frames' so as to put the buffer name in the frame title only when there is more than one frame. File: elisp, Node: Deleting Frames, Next: Finding All Frames, Prev: Frame Titles, Up: Frames Deleting Frames =============== Frames remain potentially visible until you explicitly "delete" them. A deleted frame cannot appear on the screen, but continues to exist as a Lisp object until there are no references to it. There is no way to cancel the deletion of a frame aside from restoring a saved frame configuration (*note Frame Configurations::.); this is similar to the way windows behave. - Command: delete-frame &optional FRAME This function deletes the frame FRAME. By default, FRAME is the selected frame. - Function: frame-live-p FRAME The function `frame-live-p' returns non-`nil' if the frame FRAME has not been deleted. 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 `delete-frame' event, whose normal definition is a command that calls the function `delete-frame'. *Note Misc Events::. File: elisp, Node: Finding All Frames, Next: Frames and Windows, Prev: Deleting Frames, Up: Frames Finding All Frames ================== - Function: frame-list The function `frame-list' returns a list of all the frames that have not been deleted. It is analogous to `buffer-list' for buffers. The list that you get is newly created, so modifying the list doesn't have any effect on the internals of Emacs. - Function: visible-frame-list This function returns a list of just the currently visible frames. *Note Visibility of Frames::. (Terminal frames always count as "visible", even though only the selected one is actually displayed.) - Function: next-frame &optional FRAME MINIBUF The function `next-frame' lets you cycle conveniently through all the frames from an arbitrary starting point. It returns the "next" frame after FRAME in the cycle. If FRAME is omitted or `nil', it defaults to the selected frame. The second argument, MINIBUF, says which frames to consider: `nil' Exclude minibuffer-only frames. `visible' Consider all visible frames. 0 Consider all visible or iconified frames. a window Consider only the frames using that particular window as their minibuffer. anything else Consider all frames. - Function: previous-frame &optional FRAME MINIBUF Like `next-frame', but cycles through all frames in the opposite direction. See also `next-window' and `previous-window', in *Note Cyclic Window Ordering::. File: elisp, Node: Frames and Windows, Next: Minibuffers and Frames, Prev: Finding All Frames, Up: Frames Frames and Windows ================== Each window is part of one and only one frame; you can get the frame with `window-frame'. - Function: window-frame WINDOW This function returns the frame that WINDOW is on. 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. - Function: frame-top-window FRAME This returns the topmost, leftmost window of frame FRAME. At any time, exactly one window on any frame is "selected within the frame". The significance of this designation is that selecting the frame also selects this window. You can get the frame's current selected window with `frame-selected-window'. - Function: frame-selected-window FRAME This function returns the window on FRAME that is selected within FRAME. Conversely, selecting a window for Emacs with `select-window' also makes that window selected within its frame. *Note Selecting Windows::. Another function that (usually) returns one of the windows in a frame is `minibuffer-window'. *Note Minibuffer Misc::. File: elisp, Node: Minibuffers and Frames, Next: Input Focus, Prev: Frames and Windows, Up: Frames 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 `minibuffer-window' (*note Minibuffer Misc::.). 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 `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 `minibuffer-auto-raise' to `t'. *Note Raising and Lowering::. - Variable: default-minibuffer-frame This variable specifies the frame to use for the minibuffer window, by default. It is always local to the current terminal and cannot be buffer-local. *Note Multiple Displays::. File: elisp, Node: Input Focus, Next: Visibility of Frames, Prev: Minibuffers and Frames, Up: Frames Input Focus =========== At any time, one frame in Emacs is the "selected frame". The selected window always resides on the selected frame. - Function: selected-frame This function returns the selected frame. The X server normally directs keyboard input to the X window that the mouse is in. Some window managers use mouse clicks or keyboard events to "shift the focus" to various X windows, overriding the normal behavior of the server. Lisp programs can switch frames "temporarily" by calling the function `select-frame'. This does not override the window manager; rather, it escapes from the window manager's control until that control is somehow reasserted. When using a text-only terminal, there is no window manager; therefore, `switch-frame' is the only way to switch frames, and the effect lasts until overridden by a subsequent call to `switch-frame'. Only the selected terminal frame is actually displayed on the terminal. Each terminal screen except for the initial one has a number, and the number of the selected frame appears in the mode line after the word `Emacs' (*note Mode Line Variables::.). - Function: select-frame FRAME This function selects frame FRAME, temporarily disregarding the focus of the X server if any. The selection of FRAME lasts until the next time the user does something to select a different frame, or until the next time this function is called. Emacs cooperates with the X server and the window managers by arranging to select frames according to what the server and window manager ask for. It does so by generating a special kind of input event, called a "focus" event. The command loop handles a focus event by calling `handle-switch-frame'. *Note Focus Events::. - Command: handle-switch-frame FRAME This function handles a focus event by selecting frame FRAME. Focus events normally do their job by invoking this command. Don't call it for any other reason. - Function: redirect-frame-focus FRAME FOCUS-FRAME This function redirects focus from FRAME to FOCUS-FRAME. This means that FOCUS-FRAME will receive subsequent keystrokes intended for FRAME. After such an event, the value of `last-event-frame' will be FOCUS-FRAME. Also, switch-frame events specifying FRAME will instead select FOCUS-FRAME. If FOCUS-FRAME is `nil', that cancels any existing redirection for 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 `bar', when `foo' had been selected, changes any redirections pointing to `foo' so that they point to `bar' instead. This allows focus redirection to work properly when the user switches from one frame to another using `select-window'. This means that a frame whose focus is redirected to itself is treated differently from a frame whose focus is not redirected. `select-frame' affects the former but not the latter. The redirection lasts until `redirect-frame-focus' is called to change it. File: elisp, Node: Visibility of Frames, Next: Raising and Lowering, Prev: Input Focus, Up: Frames Visibility of Frames ==================== An X window frame may be "visible", "invisible", or "iconified". If it is visible, you can see its contents. If it is iconified, the frame's contents do not appear on the screen, but an icon does. If the frame is invisible, it doesn't show 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. - Command: make-frame-visible &optional FRAME This function makes frame FRAME visible. If you omit FRAME, it makes the selected frame visible. - Command: make-frame-invisible &optional FRAME This function makes frame FRAME invisible. If you omit FRAME, it makes the selected frame invisible. - Command: iconify-frame &optional FRAME This function iconifies frame FRAME. If you omit FRAME, it iconifies the selected frame. - Function: frame-visible-p FRAME This returns the visibility status of frame FRAME. The value is `t' if FRAME is visible, `nil' if it is invisible, and `icon' if it is iconified. The visibility status of a frame is also available as a frame parameter. You can read or change it as such. *Note X Frame 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. *Note Misc Events::. File: elisp, Node: Raising and Lowering, Next: Frame Configurations, Prev: Visibility of Frames, Up: Frames Raising and Lowering Frames =========================== The X Window System uses a desktop metaphor. Part of this metaphor is the idea that windows are stacked in a notional third dimension perpendicular to the screen surface, and thus ordered from "highest" to "lowest". Where two windows overlap, the one higher up covers the one underneath. Even a window at the bottom of the stack can be seen if no other window overlaps it. A window's place in this ordering is not fixed; in fact, users tend to change the order frequently. "Raising" a window means moving it "up", to the top of the stack. "Lowering" a window means moving it to the bottom of the stack. This motion is in the notional third dimension only, and does not change the position of the window on the screen. You can raise and lower Emacs's X windows with these functions: - Command: raise-frame FRAME This function raises frame FRAME. - Command: lower-frame FRAME This function lowers frame FRAME. - User Option: minibuffer-auto-raise If this is non-`nil', activation of the minibuffer raises the frame that the minibuffer window is in. 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. *Note X Frame Parameters::. File: elisp, Node: Frame Configurations, Next: Mouse Tracking, Prev: Raising and Lowering, Up: Frames Frame Configurations ==================== A "frame configuration" records the current arrangement of frames, all their properties, and the window configuration of each one. - Function: current-frame-configuration This function returns a frame configuration list that describes the current arrangement of frames and their contents. - Function: set-frame-configuration CONFIGURATION This function restores the state of frames described in CONFIGURATION. File: elisp, Node: Mouse Tracking, Next: Mouse Position, Prev: Frame Configurations, Up: Frames Mouse Tracking ============== Sometimes it is useful to "track" the mouse, which means to display something to indicate where the mouse is and move the indicator as the mouse moves. For efficient mouse tracking, you need a way to wait until the mouse actually moves. The convenient way to track the mouse is to ask for events to represent mouse motion. Then you can wait for motion by waiting for an event. In addition, you can easily handle any other sorts of events that may occur. That is useful, because normally you don't want to track the mouse forever--only until some other event, such as the release of a button. - Special Form: track-mouse BODY... Execute BODY, meanwhile generating input events for mouse motion. The code in BODY can read these events with `read-event' or `read-key-sequence'. *Note Motion Events::, for the format of mouse motion events. The value of `track-mouse' is that of the last form in BODY. The usual purpose of tracking mouse motion is to indicate on the screen the consequences of pushing or releasing a button at the current position. In many cases, you can avoid the need to track the mouse by using the `mouse-face' text property (*note Special Properties::.). That works at a much lower level and runs more smoothly than Lisp-level mouse tracking. File: elisp, Node: Mouse Position, Next: Pop-Up Menus, Prev: Mouse Tracking, Up: Frames Mouse Position ============== The functions `mouse-position' and `set-mouse-position' give access to the current position of the mouse. - Function: mouse-position This function returns a description of the position of the mouse. The value looks like `(FRAME X . Y)', where X and Y are integers giving the position in characters relative to the top left corner of the inside of FRAME. - Function: set-mouse-position FRAME X Y This function "warps the mouse" to position X, Y in frame FRAME. The arguments X and Y are integers, giving the position in characters relative to the top left corner of the inside of FRAME. - Function: mouse-pixel-position This function is like `mouse-position' except that it returns coordinates in units of pixels rather than units of characters. - Function: set-mouse-pixel-position FRAME X Y This function warps the mouse like `set-mouse-position' except that X and Y are in units of pixels rather than units of characters. These coordinates are not required to be within the frame. File: elisp, Node: Pop-Up Menus, Next: Dialog Boxes, Prev: Mouse Position, Up: Frames Pop-Up Menus ============ When using X windows, a Lisp program can pop up a menu which the user can choose from with the mouse. - Function: x-popup-menu POSITION MENU This function displays a pop-up menu and returns an indication of what selection the user makes. The argument POSITION specifies where on the screen to put the menu. It can be either a mouse button event (which says to put the menu where the user actuated the button) or a list of this form: ((XOFFSET YOFFSET) WINDOW) where XOFFSET and YOFFSET are coordinates, measured in pixels, counting from the top left corner of WINDOW's frame. If POSITION is `t', it means to use the current mouse position. If POSITION is `nil', it means to precompute the key binding equivalents for the keymaps specified in MENU, without actually displaying or popping up the menu. The argument MENU says what to display in the menu. It can be a keymap or a list of keymaps (*note Menu Keymaps::.). Alternatively, it can have the following form: (TITLE PANE1 PANE2...) where each pane is a list of form (TITLE (LINE . ITEM)...) Each LINE should be a string, and each ITEM should be the value to return if that LINE is chosen. *Usage note:* Don't use `x-popup-menu' to display a menu if a prefix key with a menu keymap would do the job. If you use a menu keymap to implement a menu, `C-h c' and `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 `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 `x-popup-menu'. Therefore, if you try to implement a submenu using `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 `x-popup-menu'. *Note 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 `menu-bar-update-hook' to update the contents of the menu keymap as necessary. File: elisp, Node: Dialog Boxes, Next: Pointer Shapes, Prev: Pop-Up Menus, Up: Frames Dialog Boxes ============ A dialog box is a variant of a pop-up menu. It looks a little different (if Emacs uses an X toolkit), it always appears in the center of a frame, and it has just one level and one pane. The main use of dialog boxes is for asking questions that the user can answer with "yes", "no", and a few other alternatives. The functions `y-or-n-p' and `yes-or-no-p' use dialog boxes instead of the keyboard, when called from commands invoked by mouse clicks. - Function: x-popup-dialog POSITION CONTENTS This function displays a pop-up dialog box and returns an indication of what selection the user makes. The argument CONTENTS specifies the alternatives to offer; it has this format: (TITLE (STRING . VALUE)...) which looks like the list that specifies a single pane for `x-popup-menu'. The return value is VALUE from the chosen alternative. An element of the list may be just a string instead of a cons cell `(STRING . VALUE)'. That makes a box that cannot be selected. If `nil' appears in the list, it separates the left-hand items from the right-hand items; items that precede the `nil' appear on the left, and items that follow the `nil' appear on the right. If you don't include a `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 POSITION specifies which frame. The possible values are as in `x-popup-menu', but the precise coordinates don't matter; only the frame matters. If your Emacs executable does not use an X toolkit, then it cannot display a real dialog box; so instead it displays the same items in a pop-up menu in the center of the frame. File: elisp, Node: Pointer Shapes, Next: X Selections, Prev: Dialog Boxes, Up: Frames Pointer Shapes ============== These variables specify which shape to use for the mouse pointer in various situations: `x-pointer-shape' This variable specifies the pointer shape to use ordinarily in the Emacs frame. `x-sensitive-text-pointer-shape' This variable specifies the pointer shape to use when the mouse is over mouse-sensitive text. 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 updates its pointer shapes based on the current values of these variables. *Note X Frame Parameters::. The values you can use, to specify either of these pointer shapes, are defined in the file `lisp/term/x-win.el'. Use `M-x apropos RET x-pointer RET' to see a list of them. File: elisp, Node: X Selections, Next: Color Names, Prev: Pointer Shapes, Up: Frames X Selections ============ The X server records a set of "selections" which permit transfer of data between application programs. The various selections are distinguished by "selection types", represented in Emacs by symbols. X clients including Emacs can read or set the selection for any given type. - Function: x-set-selection TYPE DATA This function sets a "selection" in the X server. It takes two arguments: a selection type TYPE, and the value to assign to it, DATA. If DATA is `nil', it means to clear out the selection. Otherwise, DATA may be a string, a symbol, an integer (or a cons of two integers or list of two integers), 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 data may also be a vector of valid non-vector selection values. Each possible TYPE has its own selection value, which changes independently. The usual values of TYPE are `PRIMARY' and `SECONDARY'; these are symbols with upper-case names, in accord with X Window System conventions. The default is `PRIMARY'. - Function: 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, TYPE and DATA-TYPE. The default for TYPE, the selection type, is `PRIMARY'. The DATA-TYPE argument specifies the form of data conversion to use, to convert the raw data obtained from another X client into Lisp data. Meaningful values include `TEXT', `STRING', `TARGETS', `LENGTH', `DELETE', `FILE_NAME', `CHARACTER_POSITION', `LINE_NUMBER', `COLUMN_NUMBER', `OWNER_OS', `HOST_NAME', `USER', `CLASS', `NAME', `ATOM', and `INTEGER'. (These are symbols with upper-case names in accord with X conventions.) The default for DATA-TYPE is `STRING'. The X server also has a set of numbered "cut buffers" which can store text or other data being moved between applications. Cut buffers are considered obsolete, but Emacs supports them for the sake of X clients that still use them. - Function: x-get-cut-buffer N This function returns the contents of cut buffer number N. - Function: x-set-cut-buffer STRING This function stores STRING into the first cut buffer (cut buffer 0), moving the other values down through the series of cut buffers, much like the way successive kills in Emacs move down the kill ring. File: elisp, Node: Color Names, Next: Resources, Prev: X Selections, Up: Frames Color Names =========== - Function: x-color-defined-p COLOR &optional FRAME This function reports whether a color name is meaningful. It returns `t' if so; otherwise, `nil'. The argument FRAME says which frame's display to ask about; if FRAME is omitted or `nil', the selected frame is used. Note that this does not tell you whether the display you are using really supports that color. You can ask for any defined color on any kind of display, and you will get some result--that is how the X server works. Here's an approximate way to test whether your display supports the color COLOR: (defun x-color-supported-p (color &optional frame) (and (x-color-defined-p color frame) (or (x-display-color-p frame) (member color '("black" "white")) (and (> (x-display-planes frame) 1) (equal color "gray"))))) - Function: x-color-values COLOR &optional FRAME This function returns a value that describes what COLOR should ideally look like. If 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 in practice no value seems to be above 65280. If COLOR is not defined, the value is `nil'. (x-color-values "black") => (0 0 0) (x-color-values "white") => (65280 65280 65280) (x-color-values "red") => (65280 0 0) (x-color-values "pink") => (65280 49152 51968) (x-color-values "hungry") => nil The color values are returned for FRAME's display. If FRAME is omitted or `nil', the information is return for the selected frame's display. File: elisp, Node: Resources, Next: Server Data, Prev: Color Names, Up: Frames X Resources =========== - Function: x-get-resource ATTRIBUTE CLASS &optional COMPONENT SUBCLASS The function `x-get-resource' retrieves a resource value from the X Windows defaults database. Resources are indexed by a combination of a "key" and a "class". This function searches using a key of the form `INSTANCE.ATTRIBUTE' (where INSTANCE is the name under which Emacs was invoked), and using `Emacs.CLASS' as the class. The optional arguments COMPONENT and SUBCLASS add to the key and the class, respectively. You must specify both of them or neither. If you specify them, the key is `INSTANCE.COMPONENT.ATTRIBUTE', and the class is `Emacs.CLASS.SUBCLASS'. *Note X Resources: (emacs)Resources X. File: elisp, Node: Server Data, Prev: Resources, Up: Frames Data about the X Server ======================= This section describes functions you can use to get information about the capabilities and origin of an X display that Emacs is using. Each of these functions lets you specify the display you are interested in: the DISPLAY argument can be either a display name, or a frame (meaning use the display that frame is on). If you omit the DISPLAY argument, or specify `nil', that means to use the selected frame's display. - Function: x-display-screens &optional DISPLAY This function returns the number of screens associated with the display. - Function: x-server-version &optional DISPLAY This function returns the list of version numbers of the X server running the display. - Function: x-server-vendor &optional DISPLAY This function returns the vendor that provided the X server software. - Function: x-display-pixel-height &optional DISPLAY This function returns the height of the screen in pixels. - Function: x-display-mm-height &optional DISPLAY This function returns the height of the screen in millimeters. - Function: x-display-pixel-width &optional DISPLAY This function returns the width of the screen in pixels. - Function: x-display-mm-width &optional DISPLAY This function returns the width of the screen in millimeters. - Function: x-display-backing-store &optional DISPLAY This function returns the backing store capability of the screen. Values can be the symbols `always', `when-mapped', or `not-useful'. - Function: x-display-save-under &optional DISPLAY This function returns non-`nil' if the display supports the SaveUnder feature. - Function: x-display-planes &optional DISPLAY This function returns the number of planes the display supports. - Function: x-display-visual-class &optional DISPLAY This function returns the visual class for the screen. The value is one of the symbols `static-gray', `gray-scale', `static-color', `pseudo-color', `true-color', and `direct-color'. - Function: x-display-grayscale-p &optional DISPLAY This function returns `t' if the screen can display shades of gray. - Function: x-display-color-p &optional DISPLAY This function returns `t' if the screen is a color screen. - Function: x-display-color-cells &optional DISPLAY This function returns the number of color cells the screen supports. File: elisp, Node: Positions, Next: Markers, Prev: Frames, Up: Top Positions ********* A "position" is the index of a character in the text of a buffer. More precisely, a position identifies the place between two characters (or before the first character, or after the last character), so we can speak of the character before or after a given position. However, we often speak of the character "at" a position, meaning the character after that position. Positions are usually represented as integers starting from 1, but can also be represented as "markers"--special objects that relocate automatically when text is inserted or deleted so they stay with the surrounding characters. *Note Markers::. * Menu: * Point:: The special position where editing takes place. * Motion:: Changing point. * Excursions:: Temporary motion and buffer changes. * Narrowing:: Restricting editing to a portion of the buffer. File: elisp, Node: Point, Next: Motion, Up: Positions Point ===== "Point" is a special buffer position used by many editing commands, including the self-inserting typed characters and text insertion functions. Other commands move point through the text to allow editing and insertion at different places. Like other positions, point designates a place between two characters (or before the first character, or after the last character), rather than a particular character. Usually terminals display the cursor over the character that immediately follows point; point is actually before the character on which the cursor sits. The value of point is a number between 1 and the buffer size plus 1. If narrowing is in effect (*note Narrowing::.), then point is constrained to fall within the accessible portion of the buffer (possibly at one end of it). Each buffer has its own value of point, which is independent of the value of point in other buffers. Each window also has a value of point, which is independent of the value of point in other windows on the same buffer. This is why point can have different values in various windows that display the same buffer. When a buffer appears in only one window, the buffer's point and the window's point normally have the same value, so the distinction is rarely important. *Note Window Point::, for more details. - Function: point This function returns the value of point in the current buffer, as an integer. (point) => 175 - Function: point-min This function returns the minimum accessible value of point in the current buffer. This is normally 1, but if narrowing is in effect, it is the position of the start of the region that you narrowed to. (*Note Narrowing::.) - Function: point-max This function returns the maximum accessible value of point in the current buffer. This is `(1+ (buffer-size))', unless narrowing is in effect, in which case it is the position of the end of the region that you narrowed to. (*Note Narrowing::). - Function: buffer-end FLAG This function returns `(point-min)' if FLAG is less than 1, `(point-max)' otherwise. The argument FLAG must be a number. - Function: buffer-size This function returns the total number of characters in the current buffer. In the absence of any narrowing (*note Narrowing::.), `point-max' returns a value one larger than this. (buffer-size) => 35 (point-max) => 36 File: elisp, Node: Motion, Next: Excursions, Prev: Point, Up: Positions Motion ====== Motion functions change the value of point, either relative to the current value of point, relative to the beginning or end of the buffer, or relative to the edges of the selected window. *Note Point::. * Menu: * Character Motion:: Moving in terms of characters. * Word Motion:: Moving in terms of words. * Buffer End Motion:: Moving to the beginning or end of the buffer. * Text Lines:: Moving in terms of lines of text. * Screen Lines:: Moving in terms of lines as displayed. * List Motion:: Moving by parsing lists and sexps. * Skipping Characters:: Skipping characters belonging to a certain set.