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[Emacs-diffs] Changes to display.texi
|
From: |
Glenn Morris |
|
Subject: |
[Emacs-diffs] Changes to display.texi |
|
Date: |
Thu, 06 Sep 2007 04:10:30 +0000 |
CVSROOT: /sources/emacs
Module name: emacs
Changes by: Glenn Morris <gm> 07/09/06 04:10:29
Index: display.texi
===================================================================
RCS file: display.texi
diff -N display.texi
--- display.texi 28 Aug 2007 22:42:34 -0000 1.270
+++ /dev/null 1 Jan 1970 00:00:00 -0000
@@ -1,5442 +0,0 @@
address@hidden -*-texinfo-*-
address@hidden This is part of the GNU Emacs Lisp Reference Manual.
address@hidden Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1998, 1999,
2000, 2001,
address@hidden 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation,
Inc.
address@hidden See the file elisp.texi for copying conditions.
address@hidden ../info/display
address@hidden Display, System Interface, Processes, Top
address@hidden Emacs Display
-
- This chapter describes a number of features related to the display
-that Emacs presents to the user.
-
address@hidden
-* Refresh Screen:: Clearing the screen and redrawing everything on it.
-* Forcing Redisplay:: Forcing redisplay.
-* Truncation:: Folding or wrapping long text lines.
-* The Echo Area:: Displaying messages at the bottom of the screen.
-* Warnings:: Displaying warning messages for the user.
-* Invisible Text:: Hiding part of the buffer text.
-* Selective Display:: Hiding part of the buffer text (the old way).
-* Temporary Displays:: Displays that go away automatically.
-* Overlays:: Use overlays to highlight parts of the buffer.
-* Width:: How wide a character or string is on the screen.
-* Line Height:: Controlling the height of lines.
-* Faces:: A face defines a graphics style for text characters:
- font, colors, etc.
-* Fringes:: Controlling window fringes.
-* Scroll Bars:: Controlling vertical scroll bars.
-* Display Property:: Enabling special display features.
-* Images:: Displaying images in Emacs buffers.
-* Buttons:: Adding clickable buttons to Emacs buffers.
-* Abstract Display:: Emacs' Widget for Object Collections.
-* Blinking:: How Emacs shows the matching open parenthesis.
-* Usual Display:: The usual conventions for displaying nonprinting chars.
-* Display Tables:: How to specify other conventions.
-* Beeping:: Audible signal to the user.
-* Window Systems:: Which window system is being used.
address@hidden menu
-
address@hidden Refresh Screen
address@hidden Refreshing the Screen
-
- The function @code{redraw-frame} clears and redisplays the entire
-contents of a given frame (@pxref{Frames}). This is useful if the
-screen is corrupted.
-
address@hidden Emacs 19 feature
address@hidden redraw-frame frame
-This function clears and redisplays frame @var{frame}.
address@hidden defun
-
- Even more powerful is @code{redraw-display}:
-
address@hidden Command redraw-display
-This function clears and redisplays all visible frames.
address@hidden deffn
-
- This function calls for redisplay of certain windows, the next time
-redisplay is done, but does not clear them first.
-
address@hidden force-window-update &optional object
-This function forces some or all windows to be updated on next redisplay.
-If @var{object} is a window, it forces redisplay of that window. If
address@hidden is a buffer or buffer name, it forces redisplay of all
-windows displaying that buffer. If @var{object} is @code{nil} (or
-omitted), it forces redisplay of all windows.
address@hidden defun
-
- Processing user input takes absolute priority over redisplay. If you
-call these functions when input is available, they do nothing
-immediately, but a full redisplay does happen eventually---after all the
-input has been processed.
-
- Normally, suspending and resuming Emacs also refreshes the screen.
-Some terminal emulators record separate contents for display-oriented
-programs such as Emacs and for ordinary sequential display. If you are
-using such a terminal, you might want to inhibit the redisplay on
-resumption.
-
address@hidden no-redraw-on-reenter
address@hidden suspend (cf. @code{no-redraw-on-reenter})
address@hidden resume (cf. @code{no-redraw-on-reenter})
-This variable controls whether Emacs redraws the entire screen after it
-has been suspended and resumed. address@hidden means there is no need
-to redraw, @code{nil} means redrawing is needed. The default is @code{nil}.
address@hidden defvar
-
address@hidden Forcing Redisplay
address@hidden Forcing Redisplay
address@hidden forcing redisplay
-
- Emacs redisplay normally stops if input arrives, and does not happen
-at all if input is available before it starts. Most of the time, this
-is exactly what you want. However, you can prevent preemption by
-binding @code{redisplay-dont-pause} to a address@hidden value.
-
address@hidden redisplay-preemption-period
-This variable specifies how many seconds Emacs waits between checks
-for new input during redisplay. (The default is 0.1 seconds.) If
-input has arrived when Emacs checks, it pre-empts redisplay and
-processes the available input before trying again to redisplay.
-
-If this variable is @code{nil}, Emacs does not check for input during
-redisplay, and redisplay cannot be preempted by input.
-
-This variable is only obeyed on graphical terminals. For
-text terminals, see @ref{Terminal Output}.
address@hidden defvar
-
address@hidden redisplay-dont-pause
-If this variable is address@hidden, pending input does not
-prevent or halt redisplay; redisplay occurs, and finishes,
-regardless of whether input is available.
address@hidden defvar
-
address@hidden redisplay &optional force
-This function performs an immediate redisplay provided there are no
-pending input events. This is equivalent to @code{(sit-for 0)}.
-
-If the optional argument @var{force} is address@hidden, it forces an
-immediate and complete redisplay even if input is available.
-
-Returns @code{t} if redisplay was performed, or @code{nil} otherwise.
address@hidden defun
-
address@hidden Truncation
address@hidden Truncation
address@hidden line wrapping
address@hidden line truncation
address@hidden continuation lines
address@hidden @samp{$} in display
address@hidden @samp{\} in display
-
- When a line of text extends beyond the right edge of a window, Emacs
-can @dfn{continue} the line (make it ``wrap'' to the next screen
-line), or @dfn{truncate} the line (limit it to one screen line). The
-additional screen lines used to display a long text line are called
address@hidden lines. Continuation is not the same as filling;
-continuation happens on the screen only, not in the buffer contents,
-and it breaks a line precisely at the right margin, not at a word
-boundary. @xref{Filling}.
-
- On a graphical display, tiny arrow images in the window fringes
-indicate truncated and continued lines (@pxref{Fringes}). On a text
-terminal, a @samp{$} in the rightmost column of the window indicates
-truncation; a @samp{\} on the rightmost column indicates a line that
-``wraps.'' (The display table can specify alternate characters to use
-for this; @pxref{Display Tables}).
-
address@hidden truncate-lines
-This buffer-local variable controls how Emacs displays lines that extend
-beyond the right edge of the window. The default is @code{nil}, which
-specifies continuation. If the value is address@hidden, then these
-lines are truncated.
-
-If the variable @code{truncate-partial-width-windows} is address@hidden,
-then truncation is always used for side-by-side windows (within one
-frame) regardless of the value of @code{truncate-lines}.
address@hidden defopt
-
address@hidden default-truncate-lines
-This variable is the default value for @code{truncate-lines}, for
-buffers that do not have buffer-local values for it.
address@hidden defopt
-
address@hidden truncate-partial-width-windows
-This variable controls display of lines that extend beyond the right
-edge of the window, in side-by-side windows (@pxref{Splitting Windows}).
-If it is address@hidden, these lines are truncated; otherwise,
address@hidden says what to do with them.
address@hidden defopt
-
- When horizontal scrolling (@pxref{Horizontal Scrolling}) is in use in
-a window, that forces truncation.
-
- If your buffer contains @emph{very} long lines, and you use
-continuation to display them, just thinking about them can make Emacs
-redisplay slow. The column computation and indentation functions also
-become slow. Then you might find it advisable to set
address@hidden to @code{t}.
-
address@hidden cache-long-line-scans
-If this variable is address@hidden, various indentation and motion
-functions, and Emacs redisplay, cache the results of scanning the
-buffer, and consult the cache to avoid rescanning regions of the buffer
-unless they are modified.
-
-Turning on the cache slows down processing of short lines somewhat.
-
-This variable is automatically buffer-local in every buffer.
address@hidden defvar
-
address@hidden The Echo Area
address@hidden The Echo Area
address@hidden error display
address@hidden echo area
-
- The @dfn{echo area} is used for displaying error messages
-(@pxref{Errors}), for messages made with the @code{message} primitive,
-and for echoing keystrokes. It is not the same as the minibuffer,
-despite the fact that the minibuffer appears (when active) in the same
-place on the screen as the echo area. The @cite{GNU Emacs Manual}
-specifies the rules for resolving conflicts between the echo area and
-the minibuffer for use of that screen space (@pxref{Minibuffer,, The
-Minibuffer, emacs, The GNU Emacs Manual}).
-
- You can write output in the echo area by using the Lisp printing
-functions with @code{t} as the stream (@pxref{Output Functions}), or
-explicitly.
-
address@hidden
-* Displaying Messages:: Explicitly displaying text in the echo area.
-* Progress:: Informing user about progress of a long operation.
-* Logging Messages:: Echo area messages are logged for the user.
-* Echo Area Customization:: Controlling the echo area.
address@hidden menu
-
address@hidden Displaying Messages
address@hidden Displaying Messages in the Echo Area
address@hidden display message in echo area
-
- This section describes the functions for explicitly producing echo
-area messages. Many other Emacs features display messages there, too.
-
address@hidden message format-string &rest arguments
-This function displays a message in the echo area. The argument
address@hidden is similar to a C language @code{printf} format
-string. See @code{format} in @ref{Formatting Strings}, for the details
-on the conversion specifications. @code{message} returns the
-constructed string.
-
-In batch mode, @code{message} prints the message text on the standard
-error stream, followed by a newline.
-
-If @var{format-string}, or strings among the @var{arguments}, have
address@hidden text properties, these affect the way the message is displayed.
-
address@hidden Emacs 19 feature
-If @var{format-string} is @code{nil} or the empty string,
address@hidden clears the echo area; if the echo area has been
-expanded automatically, this brings it back to its normal size.
-If the minibuffer is active, this brings the minibuffer contents back
-onto the screen immediately.
-
address@hidden
address@hidden
-(message "Minibuffer depth is %d."
- (minibuffer-depth))
- @print{} Minibuffer depth is 0.
address@hidden "Minibuffer depth is 0."
address@hidden group
-
address@hidden
----------- Echo Area ----------
-Minibuffer depth is 0.
----------- Echo Area ----------
address@hidden group
address@hidden example
-
-To automatically display a message in the echo area or in a pop-buffer,
-depending on its size, use @code{display-message-or-buffer} (see below).
address@hidden defun
-
address@hidden with-temp-message message &rest body
-This construct displays a message in the echo area temporarily, during
-the execution of @var{body}. It displays @var{message}, executes
address@hidden, then returns the value of the last body form while restoring
-the previous echo area contents.
address@hidden defmac
-
address@hidden message-or-box format-string &rest arguments
-This function displays a message like @code{message}, but may display it
-in a dialog box instead of the echo area. If this function is called in
-a command that was invoked using the mouse---more precisely, if
address@hidden (@pxref{Command Loop Info}) is either
address@hidden or a list---then it uses a dialog box or pop-up menu to
-display the message. Otherwise, it uses the echo area. (This is the
-same criterion that @code{y-or-n-p} uses to make a similar decision; see
address@hidden Queries}.)
-
-You can force use of the mouse or of the echo area by binding
address@hidden to a suitable value around the call.
address@hidden defun
-
address@hidden message-box format-string &rest arguments
address@hidden
-This function displays a message like @code{message}, but uses a dialog
-box (or a pop-up menu) whenever that is possible. If it is impossible
-to use a dialog box or pop-up menu, because the terminal does not
-support them, then @code{message-box} uses the echo area, like
address@hidden
address@hidden defun
-
address@hidden display-message-or-buffer message &optional buffer-name
not-this-window frame
-This function displays the message @var{message}, which may be either a
-string or a buffer. If it is shorter than the maximum height of the
-echo area, as defined by @code{max-mini-window-height}, it is displayed
-in the echo area, using @code{message}. Otherwise,
address@hidden is used to show it in a pop-up buffer.
-
-Returns either the string shown in the echo area, or when a pop-up
-buffer is used, the window used to display it.
-
-If @var{message} is a string, then the optional argument
address@hidden is the name of the buffer used to display it when a
-pop-up buffer is used, defaulting to @samp{*Message*}. In the case
-where @var{message} is a string and displayed in the echo area, it is
-not specified whether the contents are inserted into the buffer anyway.
-
-The optional arguments @var{not-this-window} and @var{frame} are as for
address@hidden, and only used if a buffer is displayed.
address@hidden defun
-
address@hidden current-message
-This function returns the message currently being displayed in the
-echo area, or @code{nil} if there is none.
address@hidden defun
-
address@hidden Progress
address@hidden Reporting Operation Progress
address@hidden progress reporting
-
- When an operation can take a while to finish, you should inform the
-user about the progress it makes. This way the user can estimate
-remaining time and clearly see that Emacs is busy working, not hung.
-
- Functions listed in this section provide simple and efficient way of
-reporting operation progress. Here is a working example that does
-nothing useful:
-
address@hidden
-(let ((progress-reporter
- (make-progress-reporter "Collecting mana for Emacs..."
- 0 500)))
- (dotimes (k 500)
- (sit-for 0.01)
- (progress-reporter-update progress-reporter k))
- (progress-reporter-done progress-reporter))
address@hidden smallexample
-
address@hidden make-progress-reporter message min-value max-value &optional
current-value min-change min-time
-This function creates and returns a @dfn{progress reporter}---an
-object you will use as an argument for all other functions listed
-here. The idea is to precompute as much data as possible to make
-progress reporting very fast.
-
-When this progress reporter is subsequently used, it will display
address@hidden in the echo area, followed by progress percentage.
address@hidden is treated as a simple string. If you need it to depend
-on a filename, for instance, use @code{format} before calling this
-function.
-
address@hidden and @var{max-value} arguments stand for starting and
-final states of your operation. For instance, if you scan a buffer,
-they should be the results of @code{point-min} and @code{point-max}
-correspondingly. It is required that @var{max-value} is greater than
address@hidden If you create progress reporter when some part of
-the operation has already been completed, then specify
address@hidden argument. But normally you should omit it or set
-it to @code{nil}---it will default to @var{min-value} then.
-
-Remaining arguments control the rate of echo area updates. Progress
-reporter will wait for at least @var{min-change} more percents of the
-operation to be completed before printing next message.
address@hidden specifies the minimum time in seconds to pass between
-successive prints. It can be fractional. Depending on Emacs and
-system capabilities, progress reporter may or may not respect this
-last argument or do it with varying precision. Default value for
address@hidden is 1 (one percent), for @var{min-time}---0.2
-(seconds.)
-
-This function calls @code{progress-reporter-update}, so the first
-message is printed immediately.
address@hidden defun
-
address@hidden progress-reporter-update reporter value
-This function does the main work of reporting progress of your
-operation. It displays the message of @var{reporter}, followed by
-progress percentage determined by @var{value}. If percentage is zero,
-or close enough according to the @var{min-change} and @var{min-time}
-arguments, then it is omitted from the output.
-
address@hidden must be the result of a call to
address@hidden @var{value} specifies the current
-state of your operation and must be between @var{min-value} and
address@hidden (inclusive) as passed to
address@hidden For instance, if you scan a buffer,
-then @var{value} should be the result of a call to @code{point}.
-
-This function respects @var{min-change} and @var{min-time} as passed
-to @code{make-progress-reporter} and so does not output new messages
-on every invocation. It is thus very fast and normally you should not
-try to reduce the number of calls to it: resulting overhead will most
-likely negate your effort.
address@hidden defun
-
address@hidden progress-reporter-force-update reporter value &optional
new-message
-This function is similar to @code{progress-reporter-update} except
-that it prints a message in the echo area unconditionally.
-
-The first two arguments have the same meaning as for
address@hidden Optional @var{new-message} allows
-you to change the message of the @var{reporter}. Since this functions
-always updates the echo area, such a change will be immediately
-presented to the user.
address@hidden defun
-
address@hidden progress-reporter-done reporter
-This function should be called when the operation is finished. It
-prints the message of @var{reporter} followed by word ``done'' in the
-echo area.
-
-You should always call this function and not hope for
address@hidden to print ``100%.'' Firstly, it may
-never print it, there are many good reasons for this not to happen.
-Secondly, ``done'' is more explicit.
address@hidden defun
-
address@hidden dotimes-with-progress-reporter (var count [result]) message
address@hidden
-This is a convenience macro that works the same way as @code{dotimes}
-does, but also reports loop progress using the functions described
-above. It allows you to save some typing.
-
-You can rewrite the example in the beginning of this node using
-this macro this way:
-
address@hidden
-(dotimes-with-progress-reporter
- (k 500)
- "Collecting some mana for Emacs..."
- (sit-for 0.01))
address@hidden example
address@hidden defmac
-
address@hidden Logging Messages
address@hidden Logging Messages in @samp{*Messages*}
address@hidden logging echo-area messages
-
- Almost all the messages displayed in the echo area are also recorded
-in the @samp{*Messages*} buffer so that the user can refer back to
-them. This includes all the messages that are output with
address@hidden
-
address@hidden message-log-max
-This variable specifies how many lines to keep in the @samp{*Messages*}
-buffer. The value @code{t} means there is no limit on how many lines to
-keep. The value @code{nil} disables message logging entirely. Here's
-how to display a message and prevent it from being logged:
-
address@hidden
-(let (message-log-max)
- (message @dots{}))
address@hidden example
address@hidden defopt
-
- To make @samp{*Messages*} more convenient for the user, the logging
-facility combines successive identical messages. It also combines
-successive related messages for the sake of two cases: question
-followed by answer, and a series of progress messages.
-
- A ``question followed by an answer'' means two messages like the
-ones produced by @code{y-or-n-p}: the first is @address@hidden,
-and the second is @address@hidden@var{answer}}. The first
-message conveys no additional information beyond what's in the second,
-so logging the second message discards the first from the log.
-
- A ``series of progress messages'' means successive messages like
-those produced by @code{make-progress-reporter}. They have the form
address@hidden@address@hidden, where @var{base} is the same each
-time, while @var{how-far} varies. Logging each message in the series
-discards the previous one, provided they are consecutive.
-
- The functions @code{make-progress-reporter} and @code{y-or-n-p}
-don't have to do anything special to activate the message log
-combination feature. It operates whenever two consecutive messages
-are logged that share a common prefix ending in @samp{...}.
-
address@hidden Echo Area Customization
address@hidden Echo Area Customization
-
- These variables control details of how the echo area works.
-
address@hidden cursor-in-echo-area
-This variable controls where the cursor appears when a message is
-displayed in the echo area. If it is address@hidden, then the cursor
-appears at the end of the message. Otherwise, the cursor appears at
-point---not in the echo area at all.
-
-The value is normally @code{nil}; Lisp programs bind it to @code{t}
-for brief periods of time.
address@hidden defvar
-
address@hidden echo-area-clear-hook
-This normal hook is run whenever the echo area is cleared---either by
address@hidden(message nil)} or for any other reason.
address@hidden defvar
-
address@hidden echo-keystrokes
-This variable determines how much time should elapse before command
-characters echo. Its value must be an integer or floating point number,
-which specifies the
-number of seconds to wait before echoing. If the user types a prefix
-key (such as @kbd{C-x}) and then delays this many seconds before
-continuing, the prefix key is echoed in the echo area. (Once echoing
-begins in a key sequence, all subsequent characters in the same key
-sequence are echoed immediately.)
-
-If the value is zero, then command input is not echoed.
address@hidden defvar
-
address@hidden message-truncate-lines
-Normally, displaying a long message resizes the echo area to display
-the entire message. But if the variable @code{message-truncate-lines}
-is address@hidden, the echo area does not resize, and the message is
-truncated to fit it, as in Emacs 20 and before.
address@hidden defvar
-
- The variable @code{max-mini-window-height}, which specifies the
-maximum height for resizing minibuffer windows, also applies to the
-echo area (which is really a special use of the minibuffer window.
address@hidden Misc}.
-
address@hidden Warnings
address@hidden Reporting Warnings
address@hidden warnings
-
- @dfn{Warnings} are a facility for a program to inform the user of a
-possible problem, but continue running.
-
address@hidden
-* Warning Basics:: Warnings concepts and functions to report them.
-* Warning Variables:: Variables programs bind to customize their warnings.
-* Warning Options:: Variables users set to control display of warnings.
address@hidden menu
-
address@hidden Warning Basics
address@hidden Warning Basics
address@hidden severity level
-
- Every warning has a textual message, which explains the problem for
-the user, and a @dfn{severity level} which is a symbol. Here are the
-possible severity levels, in order of decreasing severity, and their
-meanings:
-
address@hidden @code
address@hidden :emergency
-A problem that will seriously impair Emacs operation soon
-if you do not attend to it promptly.
address@hidden :error
-A report of data or circumstances that are inherently wrong.
address@hidden :warning
-A report of data or circumstances that are not inherently wrong, but
-raise suspicion of a possible problem.
address@hidden :debug
-A report of information that may be useful if you are debugging.
address@hidden table
-
- When your program encounters invalid input data, it can either
-signal a Lisp error by calling @code{error} or @code{signal} or report
-a warning with severity @code{:error}. Signaling a Lisp error is the
-easiest thing to do, but it means the program cannot continue
-processing. If you want to take the trouble to implement a way to
-continue processing despite the bad data, then reporting a warning of
-severity @code{:error} is the right way to inform the user of the
-problem. For instance, the Emacs Lisp byte compiler can report an
-error that way and continue compiling other functions. (If the
-program signals a Lisp error and then handles it with
address@hidden, the user won't see the error message; it could
-show the message to the user by reporting it as a warning.)
-
address@hidden warning type
- Each warning has a @dfn{warning type} to classify it. The type is a
-list of symbols. The first symbol should be the custom group that you
-use for the program's user options. For example, byte compiler
-warnings use the warning type @code{(bytecomp)}. You can also
-subcategorize the warnings, if you wish, by using more symbols in the
-list.
-
address@hidden display-warning type message &optional level buffer-name
-This function reports a warning, using @var{message} as the message
-and @var{type} as the warning type. @var{level} should be the
-severity level, with @code{:warning} being the default.
-
address@hidden, if address@hidden, specifies the name of the buffer
-for logging the warning. By default, it is @samp{*Warnings*}.
address@hidden defun
-
address@hidden lwarn type level message &rest args
-This function reports a warning using the value of @code{(format
address@hidden @var{args}...)} as the message. In other respects it is
-equivalent to @code{display-warning}.
address@hidden defun
-
address@hidden warn message &rest args
-This function reports a warning using the value of @code{(format
address@hidden @var{args}...)} as the message, @code{(emacs)} as the
-type, and @code{:warning} as the severity level. It exists for
-compatibility only; we recommend not using it, because you should
-specify a specific warning type.
address@hidden defun
-
address@hidden Warning Variables
address@hidden Warning Variables
-
- Programs can customize how their warnings appear by binding
-the variables described in this section.
-
address@hidden warning-levels
-This list defines the meaning and severity order of the warning
-severity levels. Each element defines one severity level,
-and they are arranged in order of decreasing severity.
-
-Each element has the form @code{(@var{level} @var{string}
address@hidden)}, where @var{level} is the severity level it defines.
address@hidden specifies the textual description of this level.
address@hidden should use @samp{%s} to specify where to put the warning
-type information, or it can omit the @samp{%s} so as not to include
-that information.
-
-The optional @var{function}, if address@hidden, is a function to call
-with no arguments, to get the user's attention.
-
-Normally you should not change the value of this variable.
address@hidden defvar
-
address@hidden warning-prefix-function
-If address@hidden, the value is a function to generate prefix text for
-warnings. Programs can bind the variable to a suitable function.
address@hidden calls this function with the warnings buffer
-current, and the function can insert text in it. That text becomes
-the beginning of the warning message.
-
-The function is called with two arguments, the severity level and its
-entry in @code{warning-levels}. It should return a list to use as the
-entry (this value need not be an actual member of
address@hidden). By constructing this value, the function can
-change the severity of the warning, or specify different handling for
-a given severity level.
-
-If the variable's value is @code{nil} then there is no function
-to call.
address@hidden defvar
-
address@hidden warning-series
-Programs can bind this variable to @code{t} to say that the next
-warning should begin a series. When several warnings form a series,
-that means to leave point on the first warning of the series, rather
-than keep moving it for each warning so that it appears on the last one.
-The series ends when the local binding is unbound and
address@hidden becomes @code{nil} again.
-
-The value can also be a symbol with a function definition. That is
-equivalent to @code{t}, except that the next warning will also call
-the function with no arguments with the warnings buffer current. The
-function can insert text which will serve as a header for the series
-of warnings.
-
-Once a series has begun, the value is a marker which points to the
-buffer position in the warnings buffer of the start of the series.
-
-The variable's normal value is @code{nil}, which means to handle
-each warning separately.
address@hidden defvar
-
address@hidden warning-fill-prefix
-When this variable is address@hidden, it specifies a fill prefix to
-use for filling each warning's text.
address@hidden defvar
-
address@hidden warning-type-format
-This variable specifies the format for displaying the warning type
-in the warning message. The result of formatting the type this way
-gets included in the message under the control of the string in the
-entry in @code{warning-levels}. The default value is @code{" (%s)"}.
-If you bind it to @code{""} then the warning type won't appear at
-all.
address@hidden defvar
-
address@hidden Warning Options
address@hidden Warning Options
-
- These variables are used by users to control what happens
-when a Lisp program reports a warning.
-
address@hidden warning-minimum-level
-This user option specifies the minimum severity level that should be
-shown immediately to the user. The default is @code{:warning}, which
-means to immediately display all warnings except @code{:debug}
-warnings.
address@hidden defopt
-
address@hidden warning-minimum-log-level
-This user option specifies the minimum severity level that should be
-logged in the warnings buffer. The default is @code{:warning}, which
-means to log all warnings except @code{:debug} warnings.
address@hidden defopt
-
address@hidden warning-suppress-types
-This list specifies which warning types should not be displayed
-immediately for the user. Each element of the list should be a list
-of symbols. If its elements match the first elements in a warning
-type, then that warning is not displayed immediately.
address@hidden defopt
-
address@hidden warning-suppress-log-types
-This list specifies which warning types should not be logged in the
-warnings buffer. Each element of the list should be a list of
-symbols. If it matches the first few elements in a warning type, then
-that warning is not logged.
address@hidden defopt
-
address@hidden Invisible Text
address@hidden Invisible Text
-
address@hidden invisible text
-You can make characters @dfn{invisible}, so that they do not appear on
-the screen, with the @code{invisible} property. This can be either a
-text property (@pxref{Text Properties}) or a property of an overlay
-(@pxref{Overlays}). Cursor motion also partly ignores these
-characters; if the command loop finds point within them, it moves
-point to the other side of them.
-
-In the simplest case, any address@hidden @code{invisible} property makes
-a character invisible. This is the default case---if you don't alter
-the default value of @code{buffer-invisibility-spec}, this is how the
address@hidden property works. You should normally use @code{t}
-as the value of the @code{invisible} property if you don't plan
-to set @code{buffer-invisibility-spec} yourself.
-
-More generally, you can use the variable @code{buffer-invisibility-spec}
-to control which values of the @code{invisible} property make text
-invisible. This permits you to classify the text into different subsets
-in advance, by giving them different @code{invisible} values, and
-subsequently make various subsets visible or invisible by changing the
-value of @code{buffer-invisibility-spec}.
-
-Controlling visibility with @code{buffer-invisibility-spec} is
-especially useful in a program to display the list of entries in a
-database. It permits the implementation of convenient filtering
-commands to view just a part of the entries in the database. Setting
-this variable is very fast, much faster than scanning all the text in
-the buffer looking for properties to change.
-
address@hidden buffer-invisibility-spec
-This variable specifies which kinds of @code{invisible} properties
-actually make a character invisible. Setting this variable makes it
-buffer-local.
-
address@hidden @asis
address@hidden @code{t}
-A character is invisible if its @code{invisible} property is
address@hidden This is the default.
-
address@hidden a list
-Each element of the list specifies a criterion for invisibility; if a
-character's @code{invisible} property fits any one of these criteria,
-the character is invisible. The list can have two kinds of elements:
-
address@hidden @code
address@hidden @var{atom}
-A character is invisible if its @code{invisible} property value
-is @var{atom} or if it is a list with @var{atom} as a member.
-
address@hidden (@var{atom} . t)
-A character is invisible if its @code{invisible} property value is
address@hidden or if it is a list with @var{atom} as a member. Moreover,
-a sequence of such characters displays as an ellipsis.
address@hidden table
address@hidden table
address@hidden defvar
-
- Two functions are specifically provided for adding elements to
address@hidden and removing elements from it.
-
address@hidden add-to-invisibility-spec element
-This function adds the element @var{element} to
address@hidden If @code{buffer-invisibility-spec}
-was @code{t}, it changes to a list, @code{(t)}, so that text whose
address@hidden property is @code{t} remains invisible.
address@hidden defun
-
address@hidden remove-from-invisibility-spec element
-This removes the element @var{element} from
address@hidden This does nothing if @var{element}
-is not in the list.
address@hidden defun
-
- A convention for use of @code{buffer-invisibility-spec} is that a
-major mode should use the mode's own name as an element of
address@hidden and as the value of the
address@hidden property:
-
address@hidden
-;; @r{If you want to display an ellipsis:}
-(add-to-invisibility-spec '(my-symbol . t))
-;; @r{If you don't want ellipsis:}
-(add-to-invisibility-spec 'my-symbol)
-
-(overlay-put (make-overlay beginning end)
- 'invisible 'my-symbol)
-
-;; @r{When done with the overlays:}
-(remove-from-invisibility-spec '(my-symbol . t))
-;; @r{Or respectively:}
-(remove-from-invisibility-spec 'my-symbol)
address@hidden example
-
address@hidden line-move-ignore-invisible
- Ordinarily, functions that operate on text or move point do not care
-whether the text is invisible. The user-level line motion commands
-explicitly ignore invisible newlines if
address@hidden is address@hidden (the default), but
-only because they are explicitly programmed to do so.
-
- However, if a command ends with point inside or immediately before
-invisible text, the main editing loop moves point further forward or
-further backward (in the same direction that the command already moved
-it) until that condition is no longer true. Thus, if the command
-moved point back into an invisible range, Emacs moves point back to
-the beginning of that range, and then back one more character. If the
-command moved point forward into an invisible range, Emacs moves point
-forward up to the first visible character that follows the invisible
-text.
-
- Incremental search can make invisible overlays visible temporarily
-and/or permanently when a match includes invisible text. To enable
-this, the overlay should have a address@hidden
address@hidden property. The property value should be a
-function to be called with the overlay as an argument. This function
-should make the overlay visible permanently; it is used when the match
-overlaps the overlay on exit from the search.
-
- During the search, such overlays are made temporarily visible by
-temporarily modifying their invisible and intangible properties. If you
-want this to be done differently for a certain overlay, give it an
address@hidden property which is a function.
-The function is called with two arguments: the first is the overlay, and
-the second is @code{nil} to make the overlay visible, or @code{t} to
-make it invisible again.
-
address@hidden Selective Display
address@hidden Selective Display
address@hidden @cindex selective display Duplicates selective-display
-
- @dfn{Selective display} refers to a pair of related features for
-hiding certain lines on the screen.
-
- The first variant, explicit selective display, is designed for use
-in a Lisp program: it controls which lines are hidden by altering the
-text. This kind of hiding in some ways resembles the effect of the
address@hidden property (@pxref{Invisible Text}), but the two
-features are different and do not work the same way.
-
- In the second variant, the choice of lines to hide is made
-automatically based on indentation. This variant is designed to be a
-user-level feature.
-
- The way you control explicit selective display is by replacing a
-newline (control-j) with a carriage return (control-m). The text that
-was formerly a line following that newline is now hidden. Strictly
-speaking, it is temporarily no longer a line at all, since only
-newlines can separate lines; it is now part of the previous line.
-
- Selective display does not directly affect editing commands. For
-example, @kbd{C-f} (@code{forward-char}) moves point unhesitatingly
-into hidden text. However, the replacement of newline characters with
-carriage return characters affects some editing commands. For
-example, @code{next-line} skips hidden lines, since it searches only
-for newlines. Modes that use selective display can also define
-commands that take account of the newlines, or that control which
-parts of the text are hidden.
-
- When you write a selectively displayed buffer into a file, all the
-control-m's are output as newlines. This means that when you next read
-in the file, it looks OK, with nothing hidden. The selective display
-effect is seen only within Emacs.
-
address@hidden selective-display
-This buffer-local variable enables selective display. This means that
-lines, or portions of lines, may be made hidden.
-
address@hidden @bullet
address@hidden
-If the value of @code{selective-display} is @code{t}, then the character
-control-m marks the start of hidden text; the control-m, and the rest
-of the line following it, are not displayed. This is explicit selective
-display.
-
address@hidden
-If the value of @code{selective-display} is a positive integer, then
-lines that start with more than that many columns of indentation are not
-displayed.
address@hidden itemize
-
-When some portion of a buffer is hidden, the vertical movement
-commands operate as if that portion did not exist, allowing a single
address@hidden command to skip any number of hidden lines.
-However, character movement commands (such as @code{forward-char}) do
-not skip the hidden portion, and it is possible (if tricky) to insert
-or delete text in an hidden portion.
-
-In the examples below, we show the @emph{display appearance} of the
-buffer @code{foo}, which changes with the value of
address@hidden The @emph{contents} of the buffer do not
-change.
-
address@hidden
address@hidden
-(setq selective-display nil)
- @result{} nil
-
----------- Buffer: foo ----------
-1 on this column
- 2on this column
- 3n this column
- 3n this column
- 2on this column
-1 on this column
----------- Buffer: foo ----------
address@hidden group
-
address@hidden
-(setq selective-display 2)
- @result{} 2
-
----------- Buffer: foo ----------
-1 on this column
- 2on this column
- 2on this column
-1 on this column
----------- Buffer: foo ----------
address@hidden group
address@hidden example
address@hidden defvar
-
address@hidden selective-display-ellipses
-If this buffer-local variable is address@hidden, then Emacs displays
address@hidden@dots{}} at the end of a line that is followed by hidden text.
-This example is a continuation of the previous one.
-
address@hidden
address@hidden
-(setq selective-display-ellipses t)
- @result{} t
-
----------- Buffer: foo ----------
-1 on this column
- 2on this column ...
- 2on this column
-1 on this column
----------- Buffer: foo ----------
address@hidden group
address@hidden example
-
-You can use a display table to substitute other text for the ellipsis
-(@address@hidden). @xref{Display Tables}.
address@hidden defvar
-
address@hidden Temporary Displays
address@hidden Temporary Displays
-
- Temporary displays are used by Lisp programs to put output into a
-buffer and then present it to the user for perusal rather than for
-editing. Many help commands use this feature.
-
address@hidden with-output-to-temp-buffer buffer-name address@hidden
-This function executes @var{forms} while arranging to insert any output
-they print into the buffer named @var{buffer-name}, which is first
-created if necessary, and put into Help mode. Finally, the buffer is
-displayed in some window, but not selected.
-
-If the @var{forms} do not change the major mode in the output buffer,
-so that it is still Help mode at the end of their execution, then
address@hidden makes this buffer read-only at the
-end, and also scans it for function and variable names to make them
-into clickable cross-references. @xref{Docstring hyperlinks, , Tips
-for Documentation Strings}, in particular the item on hyperlinks in
-documentation strings, for more details.
-
-The string @var{buffer-name} specifies the temporary buffer, which
-need not already exist. The argument must be a string, not a buffer.
-The buffer is erased initially (with no questions asked), and it is
-marked as unmodified after @code{with-output-to-temp-buffer} exits.
-
address@hidden binds @code{standard-output} to the
-temporary buffer, then it evaluates the forms in @var{forms}. Output
-using the Lisp output functions within @var{forms} goes by default to
-that buffer (but screen display and messages in the echo area, although
-they are ``output'' in the general sense of the word, are not affected).
address@hidden Functions}.
-
-Several hooks are available for customizing the behavior
-of this construct; they are listed below.
-
-The value of the last form in @var{forms} is returned.
-
address@hidden
address@hidden
----------- Buffer: foo ----------
- This is the contents of foo.
----------- Buffer: foo ----------
address@hidden group
-
address@hidden
-(with-output-to-temp-buffer "foo"
- (print 20)
- (print standard-output))
address@hidden #<buffer foo>
-
----------- Buffer: foo ----------
-20
-
-#<buffer foo>
-
----------- Buffer: foo ----------
address@hidden group
address@hidden example
address@hidden defspec
-
address@hidden temp-buffer-show-function
-If this variable is address@hidden, @code{with-output-to-temp-buffer}
-calls it as a function to do the job of displaying a help buffer. The
-function gets one argument, which is the buffer it should display.
-
-It is a good idea for this function to run @code{temp-buffer-show-hook}
-just as @code{with-output-to-temp-buffer} normally would, inside of
address@hidden and with the chosen window and buffer
-selected.
address@hidden defvar
-
address@hidden temp-buffer-setup-hook
-This normal hook is run by @code{with-output-to-temp-buffer} before
-evaluating @var{body}. When the hook runs, the temporary buffer is
-current. This hook is normally set up with a function to put the
-buffer in Help mode.
address@hidden defvar
-
address@hidden temp-buffer-show-hook
-This normal hook is run by @code{with-output-to-temp-buffer} after
-displaying the temporary buffer. When the hook runs, the temporary buffer
-is current, and the window it was displayed in is selected. This hook
-is normally set up with a function to make the buffer read only, and
-find function names and variable names in it, provided the major mode
-is Help mode.
address@hidden defvar
-
address@hidden momentary-string-display string position &optional char message
-This function momentarily displays @var{string} in the current buffer at
address@hidden It has no effect on the undo list or on the buffer's
-modification status.
-
-The momentary display remains until the next input event. If the next
-input event is @var{char}, @code{momentary-string-display} ignores it
-and returns. Otherwise, that event remains buffered for subsequent use
-as input. Thus, typing @var{char} will simply remove the string from
-the display, while typing (say) @kbd{C-f} will remove the string from
-the display and later (presumably) move point forward. The argument
address@hidden is a space by default.
-
-The return value of @code{momentary-string-display} is not meaningful.
-
-If the string @var{string} does not contain control characters, you can
-do the same job in a more general way by creating (and then subsequently
-deleting) an overlay with a @code{before-string} property.
address@hidden Properties}.
-
-If @var{message} is address@hidden, it is displayed in the echo area
-while @var{string} is displayed in the buffer. If it is @code{nil}, a
-default message says to type @var{char} to continue.
-
-In this example, point is initially located at the beginning of the
-second line:
-
address@hidden
address@hidden
----------- Buffer: foo ----------
-This is the contents of foo.
address@hidden line.
----------- Buffer: foo ----------
address@hidden group
-
address@hidden
-(momentary-string-display
- "**** Important Message! ****"
- (point) ?\r
- "Type RET when done reading")
address@hidden t
address@hidden group
-
address@hidden
----------- Buffer: foo ----------
-This is the contents of foo.
-**** Important Message! ****Second line.
----------- Buffer: foo ----------
-
----------- Echo Area ----------
-Type RET when done reading
----------- Echo Area ----------
address@hidden group
address@hidden example
address@hidden defun
-
address@hidden Overlays
address@hidden Overlays
address@hidden overlays
-
-You can use @dfn{overlays} to alter the appearance of a buffer's text on
-the screen, for the sake of presentation features. An overlay is an
-object that belongs to a particular buffer, and has a specified
-beginning and end. It also has properties that you can examine and set;
-these affect the display of the text within the overlay.
-
-An overlay uses markers to record its beginning and end; thus,
-editing the text of the buffer adjusts the beginning and end of each
-overlay so that it stays with the text. When you create the overlay,
-you can specify whether text inserted at the beginning should be
-inside the overlay or outside, and likewise for the end of the overlay.
-
address@hidden
-* Managing Overlays:: Creating and moving overlays.
-* Overlay Properties:: How to read and set properties.
- What properties do to the screen display.
-* Finding Overlays:: Searching for overlays.
address@hidden menu
-
address@hidden Managing Overlays
address@hidden Managing Overlays
-
- This section describes the functions to create, delete and move
-overlays, and to examine their contents. Overlay changes are not
-recorded in the buffer's undo list, since the overlays are not
-part of the buffer's contents.
-
address@hidden overlayp object
-This function returns @code{t} if @var{object} is an overlay.
address@hidden defun
-
address@hidden make-overlay start end &optional buffer front-advance
rear-advance
-This function creates and returns an overlay that belongs to
address@hidden and ranges from @var{start} to @var{end}. Both @var{start}
-and @var{end} must specify buffer positions; they may be integers or
-markers. If @var{buffer} is omitted, the overlay is created in the
-current buffer.
-
-The arguments @var{front-advance} and @var{rear-advance} specify the
-marker insertion type for the start of the overlay and for the end of
-the overlay, respectively. @xref{Marker Insertion Types}. If they
-are both @code{nil}, the default, then the overlay extends to include
-any text inserted at the beginning, but not text inserted at the end.
-If @var{front-advance} is address@hidden, text inserted at the
-beginning of the overlay is excluded from the overlay. If
address@hidden is address@hidden, text inserted at the end of the
-overlay is included in the overlay.
address@hidden defun
-
address@hidden overlay-start overlay
-This function returns the position at which @var{overlay} starts,
-as an integer.
address@hidden defun
-
address@hidden overlay-end overlay
-This function returns the position at which @var{overlay} ends,
-as an integer.
address@hidden defun
-
address@hidden overlay-buffer overlay
-This function returns the buffer that @var{overlay} belongs to. It
-returns @code{nil} if @var{overlay} has been deleted.
address@hidden defun
-
address@hidden delete-overlay overlay
-This function deletes @var{overlay}. The overlay continues to exist as
-a Lisp object, and its property list is unchanged, but it ceases to be
-attached to the buffer it belonged to, and ceases to have any effect on
-display.
-
-A deleted overlay is not permanently disconnected. You can give it a
-position in a buffer again by calling @code{move-overlay}.
address@hidden defun
-
address@hidden move-overlay overlay start end &optional buffer
-This function moves @var{overlay} to @var{buffer}, and places its bounds
-at @var{start} and @var{end}. Both arguments @var{start} and @var{end}
-must specify buffer positions; they may be integers or markers.
-
-If @var{buffer} is omitted, @var{overlay} stays in the same buffer it
-was already associated with; if @var{overlay} was deleted, it goes into
-the current buffer.
-
-The return value is @var{overlay}.
-
-This is the only valid way to change the endpoints of an overlay. Do
-not try modifying the markers in the overlay by hand, as that fails to
-update other vital data structures and can cause some overlays to be
-``lost.''
address@hidden defun
-
address@hidden remove-overlays &optional start end name value
-This function removes all the overlays between @var{start} and
address@hidden whose property @var{name} has the value @var{value}. It can
-move the endpoints of the overlays in the region, or split them.
-
-If @var{name} is omitted or @code{nil}, it means to delete all overlays in
-the specified region. If @var{start} and/or @var{end} are omitted or
address@hidden, that means the beginning and end of the buffer respectively.
-Therefore, @code{(remove-overlays)} removes all the overlays in the
-current buffer.
address@hidden defun
-
- Here are some examples:
-
address@hidden
-;; @r{Create an overlay.}
-(setq foo (make-overlay 1 10))
- @result{} #<overlay from 1 to 10 in display.texi>
-(overlay-start foo)
- @result{} 1
-(overlay-end foo)
- @result{} 10
-(overlay-buffer foo)
- @result{} #<buffer display.texi>
-;; @r{Give it a property we can check later.}
-(overlay-put foo 'happy t)
- @result{} t
-;; @r{Verify the property is present.}
-(overlay-get foo 'happy)
- @result{} t
-;; @r{Move the overlay.}
-(move-overlay foo 5 20)
- @result{} #<overlay from 5 to 20 in display.texi>
-(overlay-start foo)
- @result{} 5
-(overlay-end foo)
- @result{} 20
-;; @r{Delete the overlay.}
-(delete-overlay foo)
- @result{} nil
-;; @r{Verify it is deleted.}
-foo
- @result{} #<overlay in no buffer>
-;; @r{A deleted overlay has no position.}
-(overlay-start foo)
- @result{} nil
-(overlay-end foo)
- @result{} nil
-(overlay-buffer foo)
- @result{} nil
-;; @r{Undelete the overlay.}
-(move-overlay foo 1 20)
- @result{} #<overlay from 1 to 20 in display.texi>
-;; @r{Verify the results.}
-(overlay-start foo)
- @result{} 1
-(overlay-end foo)
- @result{} 20
-(overlay-buffer foo)
- @result{} #<buffer display.texi>
-;; @r{Moving and deleting the overlay does not change its properties.}
-(overlay-get foo 'happy)
- @result{} t
address@hidden example
-
- Emacs stores the overlays of each buffer in two lists, divided
-around an arbitrary ``center position.'' One list extends backwards
-through the buffer from that center position, and the other extends
-forwards from that center position. The center position can be anywhere
-in the buffer.
-
address@hidden overlay-recenter pos
-This function recenters the overlays of the current buffer around
-position @var{pos}. That makes overlay lookup faster for positions
-near @var{pos}, but slower for positions far away from @var{pos}.
address@hidden defun
-
- A loop that scans the buffer forwards, creating overlays, can run
-faster if you do @code{(overlay-recenter (point-max))} first.
-
address@hidden Overlay Properties
address@hidden Overlay Properties
-
- Overlay properties are like text properties in that the properties that
-alter how a character is displayed can come from either source. But in
-most respects they are different. @xref{Text Properties}, for comparison.
-
- Text properties are considered a part of the text; overlays and
-their properties are specifically considered not to be part of the
-text. Thus, copying text between various buffers and strings
-preserves text properties, but does not try to preserve overlays.
-Changing a buffer's text properties marks the buffer as modified,
-while moving an overlay or changing its properties does not. Unlike
-text property changes, overlay property changes are not recorded in
-the buffer's undo list.
-
- These functions read and set the properties of an overlay:
-
address@hidden overlay-get overlay prop
-This function returns the value of property @var{prop} recorded in
address@hidden, if any. If @var{overlay} does not record any value for
-that property, but it does have a @code{category} property which is a
-symbol, that symbol's @var{prop} property is used. Otherwise, the value
-is @code{nil}.
address@hidden defun
-
address@hidden overlay-put overlay prop value
-This function sets the value of property @var{prop} recorded in
address@hidden to @var{value}. It returns @var{value}.
address@hidden defun
-
address@hidden overlay-properties overlay
-This returns a copy of the property list of @var{overlay}.
address@hidden defun
-
- See also the function @code{get-char-property} which checks both
-overlay properties and text properties for a given character.
address@hidden Properties}.
-
- Many overlay properties have special meanings; here is a table
-of them:
-
address@hidden @code
address@hidden priority
address@hidden priority @r{(overlay property)}
-This property's value (which should be a nonnegative integer number)
-determines the priority of the overlay. The priority matters when two
-or more overlays cover the same character and both specify the same
-property; the one whose @code{priority} value is larger takes priority
-over the other. For the @code{face} property, the higher priority
-value does not completely replace the other; instead, its face
-attributes override the face attributes of the lower priority
address@hidden property.
-
-Currently, all overlays take priority over text properties. Please
-avoid using negative priority values, as we have not yet decided just
-what they should mean.
-
address@hidden window
address@hidden window @r{(overlay property)}
-If the @code{window} property is address@hidden, then the overlay
-applies only on that window.
-
address@hidden category
address@hidden category @r{(overlay property)}
-If an overlay has a @code{category} property, we call it the
address@hidden of the overlay. It should be a symbol. The properties
-of the symbol serve as defaults for the properties of the overlay.
-
address@hidden face
address@hidden face @r{(overlay property)}
-This property controls the way text is displayed---for example, which
-font and which colors. @xref{Faces}, for more information.
-
-In the simplest case, the value is a face name. It can also be a list;
-then each element can be any of these possibilities:
-
address@hidden @bullet
address@hidden
-A face name (a symbol or string).
-
address@hidden
-A property list of face attributes. This has the form (@var{keyword}
address@hidden @dots{}), where each @var{keyword} is a face attribute
-name and @var{value} is a meaningful value for that attribute. With
-this feature, you do not need to create a face each time you want to
-specify a particular attribute for certain text. @xref{Face
-Attributes}.
-
address@hidden
-A cons cell, either of the form @code{(foreground-color . @var{color-name})} or
address@hidden(background-color . @var{color-name})}. These elements specify
-just the foreground color or just the background color.
-
address@hidden(foreground-color . @var{color-name})} has the same effect as
address@hidden(:foreground @var{color-name})}; likewise for the background.
address@hidden itemize
-
address@hidden mouse-face
address@hidden mouse-face @r{(overlay property)}
-This property is used instead of @code{face} when the mouse is within
-the range of the overlay.
-
address@hidden display
address@hidden display @r{(overlay property)}
-This property activates various features that change the
-way text is displayed. For example, it can make text appear taller
-or shorter, higher or lower, wider or narrower, or replaced with an image.
address@hidden Property}.
-
address@hidden help-echo
address@hidden help-echo @r{(overlay property)}
-If an overlay has a @code{help-echo} property, then when you move the
-mouse onto the text in the overlay, Emacs displays a help string in the
-echo area, or in the tooltip window. For details see @ref{Text
-help-echo}.
-
address@hidden modification-hooks
address@hidden modification-hooks @r{(overlay property)}
-This property's value is a list of functions to be called if any
-character within the overlay is changed or if text is inserted strictly
-within the overlay.
-
-The hook functions are called both before and after each change.
-If the functions save the information they receive, and compare notes
-between calls, they can determine exactly what change has been made
-in the buffer text.
-
-When called before a change, each function receives four arguments: the
-overlay, @code{nil}, and the beginning and end of the text range to be
-modified.
-
-When called after a change, each function receives five arguments: the
-overlay, @code{t}, the beginning and end of the text range just
-modified, and the length of the pre-change text replaced by that range.
-(For an insertion, the pre-change length is zero; for a deletion, that
-length is the number of characters deleted, and the post-change
-beginning and end are equal.)
-
-If these functions modify the buffer, they should bind
address@hidden to @code{t} around doing so, to
-avoid confusing the internal mechanism that calls these hooks.
-
-Text properties also support the @code{modification-hooks} property,
-but the details are somewhat different (@pxref{Special Properties}).
-
address@hidden insert-in-front-hooks
address@hidden insert-in-front-hooks @r{(overlay property)}
-This property's value is a list of functions to be called before and
-after inserting text right at the beginning of the overlay. The calling
-conventions are the same as for the @code{modification-hooks} functions.
-
address@hidden insert-behind-hooks
address@hidden insert-behind-hooks @r{(overlay property)}
-This property's value is a list of functions to be called before and
-after inserting text right at the end of the overlay. The calling
-conventions are the same as for the @code{modification-hooks} functions.
-
address@hidden invisible
address@hidden invisible @r{(overlay property)}
-The @code{invisible} property can make the text in the overlay
-invisible, which means that it does not appear on the screen.
address@hidden Text}, for details.
-
address@hidden intangible
address@hidden intangible @r{(overlay property)}
-The @code{intangible} property on an overlay works just like the
address@hidden text property. @xref{Special Properties}, for details.
-
address@hidden isearch-open-invisible
-This property tells incremental search how to make an invisible overlay
-visible, permanently, if the final match overlaps it. @xref{Invisible
-Text}.
-
address@hidden isearch-open-invisible-temporary
-This property tells incremental search how to make an invisible overlay
-visible, temporarily, during the search. @xref{Invisible Text}.
-
address@hidden before-string
address@hidden before-string @r{(overlay property)}
-This property's value is a string to add to the display at the beginning
-of the overlay. The string does not appear in the buffer in any
-sense---only on the screen.
-
address@hidden after-string
address@hidden after-string @r{(overlay property)}
-This property's value is a string to add to the display at the end of
-the overlay. The string does not appear in the buffer in any
-sense---only on the screen.
-
address@hidden evaporate
address@hidden evaporate @r{(overlay property)}
-If this property is address@hidden, the overlay is deleted automatically
-if it becomes empty (i.e., if its length becomes zero). If you give
-an empty overlay a address@hidden @code{evaporate} property, that deletes
-it immediately.
-
address@hidden local-map
address@hidden keymap of character (and overlays)
address@hidden local-map @r{(overlay property)}
-If this property is address@hidden, it specifies a keymap for a portion
-of the text. The property's value replaces the buffer's local map, when
-the character after point is within the overlay. @xref{Active Keymaps}.
-
address@hidden keymap
address@hidden keymap @r{(overlay property)}
-The @code{keymap} property is similar to @code{local-map} but overrides the
-buffer's local map (and the map specified by the @code{local-map}
-property) rather than replacing it.
address@hidden table
-
address@hidden Finding Overlays
address@hidden Searching for Overlays
-
address@hidden overlays-at pos
-This function returns a list of all the overlays that cover the
-character at position @var{pos} in the current buffer. The list is in
-no particular order. An overlay contains position @var{pos} if it
-begins at or before @var{pos}, and ends after @var{pos}.
-
-To illustrate usage, here is a Lisp function that returns a list of the
-overlays that specify property @var{prop} for the character at point:
-
address@hidden
-(defun find-overlays-specifying (prop)
- (let ((overlays (overlays-at (point)))
- found)
- (while overlays
- (let ((overlay (car overlays)))
- (if (overlay-get overlay prop)
- (setq found (cons overlay found))))
- (setq overlays (cdr overlays)))
- found))
address@hidden smallexample
address@hidden defun
-
address@hidden overlays-in beg end
-This function returns a list of the overlays that overlap the region
address@hidden through @var{end}. ``Overlap'' means that at least one
-character is contained within the overlay and also contained within the
-specified region; however, empty overlays are included in the result if
-they are located at @var{beg}, or strictly between @var{beg} and @var{end}.
address@hidden defun
-
address@hidden next-overlay-change pos
-This function returns the buffer position of the next beginning or end
-of an overlay, after @var{pos}. If there is none, it returns
address@hidden(point-max)}.
address@hidden defun
-
address@hidden previous-overlay-change pos
-This function returns the buffer position of the previous beginning or
-end of an overlay, before @var{pos}. If there is none, it returns
address@hidden(point-min)}.
address@hidden defun
-
- As an example, here's a simplified (and inefficient) version of the
-primitive function @code{next-single-char-property-change}
-(@pxref{Property Search}). It searches forward from position
address@hidden for the next position where the value of a given property
address@hidden, as obtained from either overlays or text properties,
-changes.
-
address@hidden
-(defun next-single-char-property-change (position prop)
- (save-excursion
- (goto-char position)
- (let ((propval (get-char-property (point) prop)))
- (while (and (not (eobp))
- (eq (get-char-property (point) prop) propval))
- (goto-char (min (next-overlay-change (point))
- (next-single-property-change (point) prop)))))
- (point)))
address@hidden smallexample
-
address@hidden Width
address@hidden Width
-
-Since not all characters have the same width, these functions let you
-check the width of a character. @xref{Primitive Indent}, and
address@hidden Lines}, for related functions.
-
address@hidden char-width char
-This function returns the width in columns of the character @var{char},
-if it were displayed in the current buffer and the selected window.
address@hidden defun
-
address@hidden string-width string
-This function returns the width in columns of the string @var{string},
-if it were displayed in the current buffer and the selected window.
address@hidden defun
-
address@hidden truncate-string-to-width string width &optional start-column
padding ellipsis
-This function returns the part of @var{string} that fits within
address@hidden columns, as a new string.
-
-If @var{string} does not reach @var{width}, then the result ends where
address@hidden ends. If one multi-column character in @var{string}
-extends across the column @var{width}, that character is not included in
-the result. Thus, the result can fall short of @var{width} but cannot
-go beyond it.
-
-The optional argument @var{start-column} specifies the starting column.
-If this is address@hidden, then the first @var{start-column} columns of
-the string are omitted from the value. If one multi-column character in
address@hidden extends across the column @var{start-column}, that
-character is not included.
-
-The optional argument @var{padding}, if address@hidden, is a padding
-character added at the beginning and end of the result string, to extend
-it to exactly @var{width} columns. The padding character is used at the
-end of the result if it falls short of @var{width}. It is also used at
-the beginning of the result if one multi-column character in
address@hidden extends across the column @var{start-column}.
-
-If @var{ellipsis} is address@hidden, it should be a string which will
-replace the end of @var{str} (including any padding) if it extends
-beyond @var{end-column}, unless the display width of @var{str} is
-equal to or less than the display width of @var{ellipsis}. If
address@hidden is address@hidden and not a string, it stands for
address@hidden"..."}.
-
address@hidden
-(truncate-string-to-width "\tab\t" 12 4)
- @result{} "ab"
-(truncate-string-to-width "\tab\t" 12 4 ?\s)
- @result{} " ab "
address@hidden example
address@hidden defun
-
address@hidden Line Height
address@hidden Line Height
address@hidden line height
-
- The total height of each display line consists of the height of the
-contents of the line, plus optional additional vertical line spacing
-above or below the display line.
-
- The height of the line contents is the maximum height of any
-character or image on that display line, including the final newline
-if there is one. (A display line that is continued doesn't include a
-final newline.) That is the default line height, if you do nothing to
-specify a greater height. (In the most common case, this equals the
-height of the default frame font.)
-
- There are several ways to explicitly specify a larger line height,
-either by specifying an absolute height for the display line, or by
-specifying vertical space. However, no matter what you specify, the
-actual line height can never be less than the default.
-
address@hidden line-height @r{(text property)}
- A newline can have a @code{line-height} text or overlay property
-that controls the total height of the display line ending in that
-newline.
-
- If the property value is @code{t}, the newline character has no
-effect on the displayed height of the line---the visible contents
-alone determine the height. This is useful for tiling small images
-(or image slices) without adding blank areas between the images.
-
- If the property value is a list of the form @code{(@var{height}
address@hidden)}, that adds extra space @emph{below} the display line.
-First Emacs uses @var{height} as a height spec to control extra space
address@hidden the line; then it adds enough space @emph{below} the line
-to bring the total line height up to @var{total}. In this case, the
-other ways to specify the line spacing are ignored.
-
- Any other kind of property value is a height spec, which translates
-into a number---the specified line height. There are several ways to
-write a height spec; here's how each of them translates into a number:
-
address@hidden @code
address@hidden @var{integer}
-If the height spec is a positive integer, the height value is that integer.
address@hidden @var{float}
-If the height spec is a float, @var{float}, the numeric height value
-is @var{float} times the frame's default line height.
address@hidden (@var{face} . @var{ratio})
-If the height spec is a cons of the format shown, the numeric height
-is @var{ratio} times the height of face @var{face}. @var{ratio} can
-be any type of number, or @code{nil} which means a ratio of 1.
-If @var{face} is @code{t}, it refers to the current face.
address@hidden (nil . @var{ratio})
-If the height spec is a cons of the format shown, the numeric height
-is @var{ratio} times the height of the contents of the line.
address@hidden table
-
- Thus, any valid height spec determines the height in pixels, one way
-or another. If the line contents' height is less than that, Emacs
-adds extra vertical space above the line to achieve the specified
-total height.
-
- If you don't specify the @code{line-height} property, the line's
-height consists of the contents' height plus the line spacing.
-There are several ways to specify the line spacing for different
-parts of Emacs text.
-
address@hidden default-line-spacing
- You can specify the line spacing for all lines in a frame with the
address@hidden frame parameter (@pxref{Layout Parameters}).
-However, if the variable @code{default-line-spacing} is
address@hidden, it overrides the frame's @code{line-spacing}
-parameter. An integer value specifies the number of pixels put below
-lines on graphical displays. A floating point number specifies the
-spacing relative to the frame's default line height.
-
address@hidden line-spacing
- You can specify the line spacing for all lines in a buffer via the
-buffer-local @code{line-spacing} variable. An integer value specifies
-the number of pixels put below lines on graphical displays. A floating
-point number specifies the spacing relative to the default frame line
-height. This overrides line spacings specified for the frame.
-
address@hidden line-spacing @r{(text property)}
- Finally, a newline can have a @code{line-spacing} text or overlay
-property that overrides the default frame line spacing and the buffer
-local @code{line-spacing} variable, for the display line ending in
-that newline.
-
- One way or another, these mechanisms specify a Lisp value for the
-spacing of each line. The value is a height spec, and it translates
-into a Lisp value as described above. However, in this case the
-numeric height value specifies the line spacing, rather than the line
-height.
-
address@hidden Faces
address@hidden Faces
address@hidden faces
-
- A @dfn{face} is a named collection of graphical attributes: font
-family, foreground color, background color, optional underlining, and
-many others. Faces are used in Emacs to control the style of display of
-particular parts of the text or the frame. @xref{Standard Faces,,,
-emacs, The GNU Emacs Manual}, for the list of faces Emacs normally
-comes with.
-
address@hidden face id
-Each face has its own @dfn{face number}, which distinguishes faces at
-low levels within Emacs. However, for most purposes, you refer to
-faces in Lisp programs by the symbols that name them.
-
address@hidden facep object
-This function returns @code{t} if @var{object} is a face name string
-or symbol (or if it is a vector of the kind used internally to record
-face data). It returns @code{nil} otherwise.
address@hidden defun
-
-Each face name is meaningful for all frames, and by default it has the
-same meaning in all frames. But you can arrange to give a particular
-face name a special meaning in one frame if you wish.
-
address@hidden
-* Defining Faces:: How to define a face with @code{defface}.
-* Face Attributes:: What is in a face?
-* Attribute Functions:: Functions to examine and set face attributes.
-* Displaying Faces:: How Emacs combines the faces specified for a
character.
-* Font Selection:: Finding the best available font for a face.
-* Face Functions:: How to define and examine faces.
-* Auto Faces:: Hook for automatic face assignment.
-* Font Lookup:: Looking up the names of available fonts
- and information about them.
-* Fontsets:: A fontset is a collection of fonts
- that handle a range of character sets.
address@hidden menu
-
address@hidden Defining Faces
address@hidden Defining Faces
-
- The way to define a new face is with @code{defface}. This creates a
-kind of customization item (@pxref{Customization}) which the user can
-customize using the Customization buffer (@pxref{Easy Customization,,,
-emacs, The GNU Emacs Manual}).
-
address@hidden defface face spec doc [keyword address@hidden
-This declares @var{face} as a customizable face that defaults
-according to @var{spec}. You should not quote the symbol @var{face},
-and it should not end in @samp{-face} (that would be redundant). The
-argument @var{doc} specifies the face documentation. The keywords you
-can use in @code{defface} are the same as in @code{defgroup} and
address@hidden (@pxref{Common Keywords}).
-
-When @code{defface} executes, it defines the face according to
address@hidden, then uses any customizations that were read from the
-init file (@pxref{Init File}) to override that specification.
-
-When you evaluate a @code{defface} form with @kbd{C-M-x} in Emacs
-Lisp mode (@code{eval-defun}), a special feature of @code{eval-defun}
-overrides any customizations of the face. This way, the face reflects
-exactly what the @code{defface} says.
-
-The purpose of @var{spec} is to specify how the face should appear on
-different kinds of terminals. It should be an alist whose elements
-have the form @code{(@var{display} @var{atts})}. Each element's
address@hidden, @var{display}, specifies a class of terminals. (The first
-element, if its @sc{car} is @code{default}, is special---it specifies
-defaults for the remaining elements). The element's @sc{cadr},
address@hidden, is a list of face attributes and their values; it
-specifies what the face should look like on that kind of terminal.
-The possible attributes are defined in the value of
address@hidden
-
-The @var{display} part of an element of @var{spec} determines which
-frames the element matches. If more than one element of @var{spec}
-matches a given frame, the first element that matches is the one used
-for that frame. There are three possibilities for @var{display}:
-
address@hidden @asis
address@hidden @code{default}
-This element of @var{spec} doesn't match any frames; instead, it
-specifies defaults that apply to all frames. This kind of element, if
-used, must be the first element of @var{spec}. Each of the following
-elements can override any or all of these defaults.
-
address@hidden @code{t}
-This element of @var{spec} matches all frames. Therefore, any
-subsequent elements of @var{spec} are never used. Normally
address@hidden is used in the last (or only) element of @var{spec}.
-
address@hidden a list
-If @var{display} is a list, each element should have the form
address@hidden(@var{characteristic} @address@hidden)}. Here
address@hidden specifies a way of classifying frames, and the
address@hidden are possible classifications which @var{display} should
-apply to. Here are the possible values of @var{characteristic}:
-
address@hidden @code
address@hidden type
-The kind of window system the frame uses---either @code{graphic} (any
-graphics-capable display), @code{x}, @code{pc} (for the MS-DOS console),
address@hidden (for MS Windows 9X/NT/2K/XP), @code{mac} (for the Macintosh
-display), or @code{tty} (a non-graphics-capable display).
address@hidden Systems, window-system}.
-
address@hidden class
-What kinds of colors the frame supports---either @code{color},
address@hidden, or @code{mono}.
-
address@hidden background
-The kind of background---either @code{light} or @code{dark}.
-
address@hidden min-colors
-An integer that represents the minimum number of colors the frame
-should support. This matches a frame if its
address@hidden value is at least the specified integer.
-
address@hidden supports
-Whether or not the frame can display the face attributes given in
address@hidden@dots{} (@pxref{Face Attributes}). See the documentation
-for the function @code{display-supports-face-attributes-p} for more
-information on exactly how this testing is done. @xref{Display Face
-Attribute Testing}.
address@hidden table
-
-If an element of @var{display} specifies more than one @var{value} for a
-given @var{characteristic}, any of those values is acceptable. If
address@hidden has more than one element, each element should specify a
-different @var{characteristic}; then @emph{each} characteristic of the
-frame must match one of the @var{value}s specified for it in
address@hidden
address@hidden table
address@hidden defmac
-
- Here's how the standard face @code{region} is defined:
-
address@hidden
address@hidden
-(defface region
- '((((class color) (min-colors 88) (background dark))
- :background "blue3")
address@hidden group
- (((class color) (min-colors 88) (background light))
- :background "lightgoldenrod2")
- (((class color) (min-colors 16) (background dark))
- :background "blue3")
- (((class color) (min-colors 16) (background light))
- :background "lightgoldenrod2")
- (((class color) (min-colors 8))
- :background "blue" :foreground "white")
- (((type tty) (class mono))
- :inverse-video t)
- (t :background "gray"))
address@hidden
- "Basic face for highlighting the region."
- :group 'basic-faces)
address@hidden group
address@hidden example
-
- Internally, @code{defface} uses the symbol property
address@hidden to record the face attributes specified in
address@hidden, @code{saved-face} for the attributes saved by the user
-with the customization buffer, @code{customized-face} for the
-attributes customized by the user for the current session, but not
-saved, and @code{face-documentation} for the documentation string.
-
address@hidden frame-background-mode
-This option, if address@hidden, specifies the background type to use for
-interpreting face definitions. If it is @code{dark}, then Emacs treats
-all frames as if they had a dark background, regardless of their actual
-background colors. If it is @code{light}, then Emacs treats all frames
-as if they had a light background.
address@hidden defopt
-
address@hidden Face Attributes
address@hidden Face Attributes
address@hidden face attributes
-
- The effect of using a face is determined by a fixed set of @dfn{face
-attributes}. This table lists all the face attributes, and what they
-mean. You can specify more than one face for a given piece of text;
-Emacs merges the attributes of all the faces to determine how to
-display the text. @xref{Displaying Faces}.
-
- Any attribute in a face can have the value @code{unspecified}. This
-means the face doesn't specify that attribute. In face merging, when
-the first face fails to specify a particular attribute, that means the
-next face gets a chance. However, the @code{default} face must
-specify all attributes.
-
- Some of these font attributes are meaningful only on certain kinds of
-displays---if your display cannot handle a certain attribute, the
-attribute is ignored. (The attributes @code{:family}, @code{:width},
address@hidden:height}, @code{:weight}, and @code{:slant} correspond to parts of
-an X Logical Font Descriptor.)
-
address@hidden @code
address@hidden :family
-Font family name, or fontset name (@pxref{Fontsets}). If you specify a
-font family name, the wild-card characters @samp{*} and @samp{?} are
-allowed.
-
address@hidden :width
-Relative proportionate width, also known as the character set width or
-set width. This should be one of the symbols @code{ultra-condensed},
address@hidden, @code{condensed}, @code{semi-condensed},
address@hidden, @code{semi-expanded}, @code{expanded},
address@hidden, or @code{ultra-expanded}.
-
address@hidden :height
-Either the font height, an integer in units of 1/10 point, a floating
-point number specifying the amount by which to scale the height of any
-underlying face, or a function, which is called with the old height
-(from the underlying face), and should return the new height.
-
address@hidden :weight
-Font weight---a symbol from this series (from most dense to most faint):
address@hidden, @code{extra-bold}, @code{bold}, @code{semi-bold},
address@hidden, @code{semi-light}, @code{light}, @code{extra-light},
-or @code{ultra-light}.
-
-On a text-only terminal, any weight greater than normal is displayed as
-extra bright, and any weight less than normal is displayed as
-half-bright (provided the terminal supports the feature).
-
address@hidden :slant
-Font slant---one of the symbols @code{italic}, @code{oblique}, @code{normal},
address@hidden, or @code{reverse-oblique}.
-
-On a text-only terminal, slanted text is displayed as half-bright, if
-the terminal supports the feature.
-
address@hidden :foreground
-Foreground color, a string. The value can be a system-defined color
-name, or a hexadecimal color specification of the form
address@hidden@address@hidden@var{bb}}. (@samp{#000000} is black,
address@hidden is red, @samp{#00ff00} is green, @samp{#0000ff} is
-blue, and @samp{#ffffff} is white.)
-
address@hidden :background
-Background color, a string, like the foreground color.
-
address@hidden :inverse-video
-Whether or not characters should be displayed in inverse video. The
-value should be @code{t} (yes) or @code{nil} (no).
-
address@hidden :stipple
-The background stipple, a bitmap.
-
-The value can be a string; that should be the name of a file containing
-external-format X bitmap data. The file is found in the directories
-listed in the variable @code{x-bitmap-file-path}.
-
-Alternatively, the value can specify the bitmap directly, with a list
-of the form @code{(@var{width} @var{height} @var{data})}. Here,
address@hidden and @var{height} specify the size in pixels, and
address@hidden is a string containing the raw bits of the bitmap, row by
-row. Each row occupies @math{(@var{width} + 7) / 8} consecutive bytes
-in the string (which should be a unibyte string for best results).
-This means that each row always occupies at least one whole byte.
-
-If the value is @code{nil}, that means use no stipple pattern.
-
-Normally you do not need to set the stipple attribute, because it is
-used automatically to handle certain shades of gray.
-
address@hidden :underline
-Whether or not characters should be underlined, and in what color. If
-the value is @code{t}, underlining uses the foreground color of the
-face. If the value is a string, underlining uses that color. The
-value @code{nil} means do not underline.
-
address@hidden :overline
-Whether or not characters should be overlined, and in what color.
-The value is used like that of @code{:underline}.
-
address@hidden :strike-through
-Whether or not characters should be strike-through, and in what
-color. The value is used like that of @code{:underline}.
-
address@hidden :inherit
-The name of a face from which to inherit attributes, or a list of face
-names. Attributes from inherited faces are merged into the face like an
-underlying face would be, with higher priority than underlying faces.
-If a list of faces is used, attributes from faces earlier in the list
-override those from later faces.
-
address@hidden :box
-Whether or not a box should be drawn around characters, its color, the
-width of the box lines, and 3D appearance.
address@hidden table
-
- Here are the possible values of the @code{:box} attribute, and what
-they mean:
-
address@hidden @asis
address@hidden @code{nil}
-Don't draw a box.
-
address@hidden @code{t}
-Draw a box with lines of width 1, in the foreground color.
-
address@hidden @var{color}
-Draw a box with lines of width 1, in color @var{color}.
-
address@hidden @code{(:line-width @var{width} :color @var{color} :style
@var{style})}
-This way you can explicitly specify all aspects of the box. The value
address@hidden specifies the width of the lines to draw; it defaults to 1.
-
-The value @var{color} specifies the color to draw with. The default is
-the foreground color of the face for simple boxes, and the background
-color of the face for 3D boxes.
-
-The value @var{style} specifies whether to draw a 3D box. If it is
address@hidden, the box looks like a 3D button that is not being
-pressed. If it is @code{pressed-button}, the box looks like a 3D button
-that is being pressed. If it is @code{nil} or omitted, a plain 2D box
-is used.
address@hidden table
-
- In older versions of Emacs, before @code{:family}, @code{:height},
address@hidden:width}, @code{:weight}, and @code{:slant} existed, these
-attributes were used to specify the type face. They are now
-semi-obsolete, but they still work:
-
address@hidden @code
address@hidden :font
-This attribute specifies the font name.
-
address@hidden :bold
-A address@hidden value specifies a bold font.
-
address@hidden :italic
-A address@hidden value specifies an italic font.
address@hidden table
-
- For compatibility, you can still set these ``attributes,'' even
-though they are not real face attributes. Here is what that does:
-
address@hidden @code
address@hidden :font
-You can specify an X font name as the ``value'' of this ``attribute'';
-that sets the @code{:family}, @code{:width}, @code{:height},
address@hidden:weight}, and @code{:slant} attributes according to the font name.
-
-If the value is a pattern with wildcards, the first font that matches
-the pattern is used to set these attributes.
-
address@hidden :bold
-A address@hidden makes the face bold; @code{nil} makes it normal.
-This actually works by setting the @code{:weight} attribute.
-
address@hidden :italic
-A address@hidden makes the face italic; @code{nil} makes it normal.
-This actually works by setting the @code{:slant} attribute.
address@hidden table
-
address@hidden x-bitmap-file-path
-This variable specifies a list of directories for searching
-for bitmap files, for the @code{:stipple} attribute.
address@hidden defvar
-
address@hidden bitmap-spec-p object
-This returns @code{t} if @var{object} is a valid bitmap specification,
-suitable for use with @code{:stipple} (see above). It returns
address@hidden otherwise.
address@hidden defun
-
address@hidden Attribute Functions
address@hidden Face Attribute Functions
-
- This section describes the functions for accessing and modifying the
-attributes of an existing face.
-
address@hidden set-face-attribute face frame &rest arguments
-This function sets one or more attributes of face @var{face} for frame
address@hidden The attributes you specify this way override whatever
-the @code{defface} says.
-
-The extra arguments @var{arguments} specify the attributes to set, and
-the values for them. They should consist of alternating attribute names
-(such as @code{:family} or @code{:underline}) and corresponding values.
-Thus,
-
address@hidden
-(set-face-attribute 'foo nil
- :width 'extended
- :weight 'bold
- :underline "red")
address@hidden example
-
address@hidden
-sets the attributes @code{:width}, @code{:weight} and @code{:underline}
-to the corresponding values.
-
-If @var{frame} is @code{t}, this function sets the default attributes
-for new frames. Default attribute values specified this way override
-the @code{defface} for newly created frames.
-
-If @var{frame} is @code{nil}, this function sets the attributes for
-all existing frames, and the default for new frames.
address@hidden defun
-
address@hidden face-attribute face attribute &optional frame inherit
-This returns the value of the @var{attribute} attribute of face
address@hidden on @var{frame}. If @var{frame} is @code{nil},
-that means the selected frame (@pxref{Input Focus}).
-
-If @var{frame} is @code{t}, this returns whatever new-frames default
-value you previously specified with @code{set-face-attribute} for the
address@hidden attribute of @var{face}. If you have not specified
-one, it returns @code{nil}.
-
-If @var{inherit} is @code{nil}, only attributes directly defined by
address@hidden are considered, so the return value may be
address@hidden, or a relative value. If @var{inherit} is
address@hidden, @var{face}'s definition of @var{attribute} is merged
-with the faces specified by its @code{:inherit} attribute; however the
-return value may still be @code{unspecified} or relative. If
address@hidden is a face or a list of faces, then the result is further
-merged with that face (or faces), until it becomes specified and
-absolute.
-
-To ensure that the return value is always specified and absolute, use
-a value of @code{default} for @var{inherit}; this will resolve any
-unspecified or relative values by merging with the @code{default} face
-(which is always completely specified).
-
-For example,
-
address@hidden
-(face-attribute 'bold :weight)
- @result{} bold
address@hidden example
address@hidden defun
-
address@hidden face-attribute-relative-p attribute value
-This function returns address@hidden if @var{value}, when used as the
-value of the face attribute @var{attribute}, is relative. This means
-it would modify, rather than completely override, any value that comes
-from a subsequent face in the face list or that is inherited from
-another face.
-
address@hidden is a relative value for all attributes.
-For @code{:height}, floating point values are also relative.
-
-For example:
-
address@hidden
-(face-attribute-relative-p :height 2.0)
- @result{} t
address@hidden example
address@hidden defun
-
address@hidden merge-face-attribute attribute value1 value2
-If @var{value1} is a relative value for the face attribute
address@hidden, returns it merged with the underlying value
address@hidden; otherwise, if @var{value1} is an absolute value for the
-face attribute @var{attribute}, returns @var{value1} unchanged.
address@hidden defun
-
- The functions above did not exist before Emacs 21. For compatibility
-with older Emacs versions, you can use the following functions to set
-and examine the face attributes which existed in those versions.
-They use values of @code{t} and @code{nil} for @var{frame}
-just like @code{set-face-attribute} and @code{face-attribute}.
-
address@hidden set-face-foreground face color &optional frame
address@hidden set-face-background face color &optional frame
-These functions set the foreground (or background, respectively) color
-of face @var{face} to @var{color}. The argument @var{color} should be a
-string, the name of a color.
-
-Certain shades of gray are implemented by stipple patterns on
-black-and-white screens.
address@hidden defun
-
address@hidden set-face-stipple face pattern &optional frame
-This function sets the background stipple pattern of face @var{face}
-to @var{pattern}. The argument @var{pattern} should be the name of a
-stipple pattern defined by the X server, or actual bitmap data
-(@pxref{Face Attributes}), or @code{nil} meaning don't use stipple.
-
-Normally there is no need to pay attention to stipple patterns, because
-they are used automatically to handle certain shades of gray.
address@hidden defun
-
address@hidden set-face-font face font &optional frame
-This function sets the font of face @var{face}. This actually sets
-the attributes @code{:family}, @code{:width}, @code{:height},
address@hidden:weight}, and @code{:slant} according to the font name
address@hidden
address@hidden defun
-
address@hidden set-face-bold-p face bold-p &optional frame
-This function specifies whether @var{face} should be bold. If
address@hidden is address@hidden, that means yes; @code{nil} means no.
-This actually sets the @code{:weight} attribute.
address@hidden defun
-
address@hidden set-face-italic-p face italic-p &optional frame
-This function specifies whether @var{face} should be italic. If
address@hidden is address@hidden, that means yes; @code{nil} means no.
-This actually sets the @code{:slant} attribute.
address@hidden defun
-
address@hidden set-face-underline-p face underline &optional frame
-This function sets the underline attribute of face @var{face}.
address@hidden means do underline; @code{nil} means don't.
-If @var{underline} is a string, underline with that color.
address@hidden defun
-
address@hidden set-face-inverse-video-p face inverse-video-p &optional frame
-This function sets the @code{:inverse-video} attribute of face
address@hidden
address@hidden defun
-
address@hidden invert-face face &optional frame
-This function swaps the foreground and background colors of face
address@hidden
address@hidden defun
-
- These functions examine the attributes of a face. If you don't
-specify @var{frame}, they refer to the selected frame; @code{t} refers
-to the default data for new frames. They return the symbol
address@hidden if the face doesn't define any value for that
-attribute.
-
address@hidden face-foreground face &optional frame inherit
address@hidden face-background face &optional frame inherit
-These functions return the foreground color (or background color,
-respectively) of face @var{face}, as a string.
-
-If @var{inherit} is @code{nil}, only a color directly defined by the face is
-returned. If @var{inherit} is address@hidden, any faces specified by its
address@hidden:inherit} attribute are considered as well, and if @var{inherit}
-is a face or a list of faces, then they are also considered, until a
-specified color is found. To ensure that the return value is always
-specified, use a value of @code{default} for @var{inherit}.
address@hidden defun
-
address@hidden face-stipple face &optional frame inherit
-This function returns the name of the background stipple pattern of face
address@hidden, or @code{nil} if it doesn't have one.
-
-If @var{inherit} is @code{nil}, only a stipple directly defined by the
-face is returned. If @var{inherit} is address@hidden, any faces
-specified by its @code{:inherit} attribute are considered as well, and
-if @var{inherit} is a face or a list of faces, then they are also
-considered, until a specified stipple is found. To ensure that the
-return value is always specified, use a value of @code{default} for
address@hidden
address@hidden defun
-
address@hidden face-font face &optional frame
-This function returns the name of the font of face @var{face}.
address@hidden defun
-
address@hidden face-bold-p face &optional frame
-This function returns @code{t} if @var{face} is bold---that is, if it is
-bolder than normal. It returns @code{nil} otherwise.
address@hidden defun
-
address@hidden face-italic-p face &optional frame
-This function returns @code{t} if @var{face} is italic or oblique,
address@hidden otherwise.
address@hidden defun
-
address@hidden face-underline-p face &optional frame
-This function returns the @code{:underline} attribute of face @var{face}.
address@hidden defun
-
address@hidden face-inverse-video-p face &optional frame
-This function returns the @code{:inverse-video} attribute of face @var{face}.
address@hidden defun
-
address@hidden Displaying Faces
address@hidden Displaying Faces
-
- Here are the ways to specify which faces to use for display of text:
-
address@hidden @bullet
address@hidden
-With defaults. The @code{default} face is used as the ultimate
-default for all text. (In Emacs 19 and 20, the @code{default}
-face is used only when no other face is specified.)
-
address@hidden
-For a mode line or header line, the face @code{mode-line} or
address@hidden, or @code{header-line}, is merged in just
-before @code{default}.
-
address@hidden
-With text properties. A character can have a @code{face} property; if
-so, the faces and face attributes specified there apply. @xref{Special
-Properties}.
-
-If the character has a @code{mouse-face} property, that is used instead
-of the @code{face} property when the mouse is ``near enough'' to the
-character.
-
address@hidden
-With overlays. An overlay can have @code{face} and @code{mouse-face}
-properties too; they apply to all the text covered by the overlay.
-
address@hidden
-With a region that is active. In Transient Mark mode, the region is
-highlighted with the face @code{region} (@pxref{Standard Faces,,,
-emacs, The GNU Emacs Manual}).
-
address@hidden
-With special glyphs. Each glyph can specify a particular face
-number. @xref{Glyphs}.
address@hidden itemize
-
- If these various sources together specify more than one face for a
-particular character, Emacs merges the attributes of the various faces
-specified. For each attribute, Emacs tries first the face of any
-special glyph; then the face for region highlighting, if appropriate;
-then the faces specified by overlays, followed by those specified by
-text properties, then the @code{mode-line} or
address@hidden or @code{header-line} face (if in a mode
-line or a header line), and last the @code{default} face.
-
- When multiple overlays cover one character, an overlay with higher
-priority overrides those with lower priority. @xref{Overlays}.
-
address@hidden Font Selection
address@hidden Font Selection
-
- @dfn{Selecting a font} means mapping the specified face attributes for
-a character to a font that is available on a particular display. The
-face attributes, as determined by face merging, specify most of the
-font choice, but not all. Part of the choice depends on what character
-it is.
-
- If the face specifies a fontset name, that fontset determines a
-pattern for fonts of the given charset. If the face specifies a font
-family, a font pattern is constructed.
-
- Emacs tries to find an available font for the given face attributes
-and character's registry and encoding. If there is a font that matches
-exactly, it is used, of course. The hard case is when no available font
-exactly fits the specification. Then Emacs looks for one that is
-``close''---one attribute at a time. You can specify the order to
-consider the attributes. In the case where a specified font family is
-not available, you can specify a set of mappings for alternatives to
-try.
-
address@hidden face-font-selection-order
-This variable specifies the order of importance of the face attributes
address@hidden:width}, @code{:height}, @code{:weight}, and @code{:slant}. The
-value should be a list containing those four symbols, in order of
-decreasing importance.
-
-Font selection first finds the best available matches for the first
-attribute listed; then, among the fonts which are best in that way, it
-searches for the best matches in the second attribute, and so on.
-
-The attributes @code{:weight} and @code{:width} have symbolic values in
-a range centered around @code{normal}. Matches that are more extreme
-(farther from @code{normal}) are somewhat preferred to matches that are
-less extreme (closer to @code{normal}); this is designed to ensure that
-non-normal faces contrast with normal ones, whenever possible.
-
-The default is @code{(:width :height :weight :slant)}, which means first
-find the fonts closest to the specified @code{:width}, then---among the
-fonts with that width---find a best match for the specified font height,
-and so on.
-
-One example of a case where this variable makes a difference is when the
-default font has no italic equivalent. With the default ordering, the
address@hidden face will use a non-italic font that is similar to the
-default one. But if you put @code{:slant} before @code{:height}, the
address@hidden face will use an italic font, even if its height is not
-quite right.
address@hidden defvar
-
address@hidden face-font-family-alternatives
-This variable lets you specify alternative font families to try, if a
-given family is specified and doesn't exist. Each element should have
-this form:
-
address@hidden
-(@var{family} @address@hidden)
address@hidden example
-
-If @var{family} is specified but not available, Emacs will try the other
-families given in @var{alternate-families}, one by one, until it finds a
-family that does exist.
address@hidden defvar
-
address@hidden face-font-registry-alternatives
-This variable lets you specify alternative font registries to try, if a
-given registry is specified and doesn't exist. Each element should have
-this form:
-
address@hidden
-(@var{registry} @address@hidden)
address@hidden example
-
-If @var{registry} is specified but not available, Emacs will try the
-other registries given in @var{alternate-registries}, one by one,
-until it finds a registry that does exist.
address@hidden defvar
-
- Emacs can make use of scalable fonts, but by default it does not use
-them, since the use of too many or too big scalable fonts can crash
-XFree86 servers.
-
address@hidden scalable-fonts-allowed
-This variable controls which scalable fonts to use. A value of
address@hidden, the default, means do not use scalable fonts. @code{t}
-means to use any scalable font that seems appropriate for the text.
-
-Otherwise, the value must be a list of regular expressions. Then a
-scalable font is enabled for use if its name matches any regular
-expression in the list. For example,
-
address@hidden
-(setq scalable-fonts-allowed '("muleindian-2$"))
address@hidden example
-
address@hidden
-allows the use of scalable fonts with registry @code{muleindian-2}.
address@hidden defvar
-
address@hidden face-font-rescale-alist
-This variable specifies scaling for certain faces. Its value should
-be a list of elements of the form
-
address@hidden
-(@var{fontname-regexp} . @var{scale-factor})
address@hidden example
-
-If @var{fontname-regexp} matches the font name that is about to be
-used, this says to choose a larger similar font according to the
-factor @var{scale-factor}. You would use this feature to normalize
-the font size if certain fonts are bigger or smaller than their
-nominal heights and widths would suggest.
address@hidden defvar
-
address@hidden Face Functions
address@hidden Functions for Working with Faces
-
- Here are additional functions for creating and working with faces.
-
address@hidden make-face name
-This function defines a new face named @var{name}, initially with all
-attributes @code{nil}. It does nothing if there is already a face named
address@hidden
address@hidden defun
-
address@hidden face-list
-This function returns a list of all defined face names.
address@hidden defun
-
address@hidden copy-face old-face new-name &optional frame new-frame
-This function defines a face named @var{new-name} as a copy of the existing
-face named @var{old-face}. It creates the face @var{new-name} if that
-doesn't already exist.
-
-If the optional argument @var{frame} is given, this function applies
-only to that frame. Otherwise it applies to each frame individually,
-copying attributes from @var{old-face} in each frame to @var{new-face}
-in the same frame.
-
-If the optional argument @var{new-frame} is given, then @code{copy-face}
-copies the attributes of @var{old-face} in @var{frame} to @var{new-name}
-in @var{new-frame}.
address@hidden defun
-
address@hidden face-id face
-This function returns the face number of face @var{face}.
address@hidden defun
-
address@hidden face-documentation face
-This function returns the documentation string of face @var{face}, or
address@hidden if none was specified for it.
address@hidden defun
-
address@hidden face-equal face1 face2 &optional frame
-This returns @code{t} if the faces @var{face1} and @var{face2} have the
-same attributes for display.
address@hidden defun
-
address@hidden face-differs-from-default-p face &optional frame
-This returns address@hidden if the face @var{face} displays
-differently from the default face.
address@hidden defun
-
address@hidden face alias
-A @dfn{face alias} provides an equivalent name for a face. You can
-define a face alias by giving the alias symbol the @code{face-alias}
-property, with a value of the target face name. The following example
-makes @code{modeline} an alias for the @code{mode-line} face.
-
address@hidden
-(put 'modeline 'face-alias 'mode-line)
address@hidden example
-
-
address@hidden Auto Faces
address@hidden Automatic Face Assignment
address@hidden automatic face assignment
address@hidden faces, automatic choice
-
- This hook is used for automatically assigning facesto text in the
-buffer. It is part of the implementation of Jit-Lock mode, used by
-Font-Lock.
-
address@hidden fontification-functions
-This variable holds a list of functions that are called by Emacs
-redisplay as needed to assign faces automatically to text in the buffer.
-
-The functions are called in the order listed, with one argument, a
-buffer position @var{pos}. Each function should attempt to assign faces
-to the text in the current buffer starting at @var{pos}.
-
-Each function should record the faces they assign by setting the
address@hidden property. It should also add a address@hidden
address@hidden property for all the text it has assigned faces to.
-That property tells redisplay that faces have been assigned to that text
-already.
-
-It is probably a good idea for each function to do nothing if the
-character after @var{pos} already has a address@hidden @code{fontified}
-property, but this is not required. If one function overrides the
-assignments made by a previous one, the properties as they are
-after the last function finishes are the ones that really matter.
-
-For efficiency, we recommend writing these functions so that they
-usually assign faces to around 400 to 600 characters at each call.
address@hidden defvar
-
address@hidden Font Lookup
address@hidden Looking Up Fonts
-
address@hidden x-list-fonts pattern &optional face frame maximum
-This function returns a list of available font names that match
address@hidden If the optional arguments @var{face} and @var{frame} are
-specified, then the list is limited to fonts that are the same size as
address@hidden currently is on @var{frame}.
-
-The argument @var{pattern} should be a string, perhaps with wildcard
-characters: the @samp{*} character matches any substring, and the
address@hidden character matches any single character. Pattern matching
-of font names ignores case.
-
-If you specify @var{face} and @var{frame}, @var{face} should be a face name
-(a symbol) and @var{frame} should be a frame.
-
-The optional argument @var{maximum} sets a limit on how many fonts to
-return. If this is address@hidden, then the return value is truncated
-after the first @var{maximum} matching fonts. Specifying a small value
-for @var{maximum} can make this function much faster, in cases where
-many fonts match the pattern.
address@hidden defun
-
address@hidden x-family-fonts &optional family frame
-This function returns a list describing the available fonts for family
address@hidden on @var{frame}. If @var{family} is omitted or @code{nil},
-this list applies to all families, and therefore, it contains all
-available fonts. Otherwise, @var{family} must be a string; it may
-contain the wildcards @samp{?} and @samp{*}.
-
-The list describes the display that @var{frame} is on; if @var{frame} is
-omitted or @code{nil}, it applies to the selected frame's display
-(@pxref{Input Focus}).
-
-The list contains a vector of the following form for each font:
-
address@hidden
address@hidden @var{width} @var{point-size} @var{weight} @var{slant}
- @var{fixed-p} @var{full} @var{registry-and-encoding}]
address@hidden example
-
-The first five elements correspond to face attributes; if you
-specify these attributes for a face, it will use this font.
-
-The last three elements give additional information about the font.
address@hidden is address@hidden if the font is fixed-pitch.
address@hidden is the full name of the font, and
address@hidden is a string giving the registry and
-encoding of the font.
-
-The result list is sorted according to the current face font sort order.
address@hidden defun
-
address@hidden x-font-family-list &optional frame
-This function returns a list of the font families available for
address@hidden's display. If @var{frame} is omitted or @code{nil}, it
-describes the selected frame's display (@pxref{Input Focus}).
-
-The value is a list of elements of this form:
-
address@hidden
-(@var{family} . @var{fixed-p})
address@hidden example
-
address@hidden
-Here @var{family} is a font family, and @var{fixed-p} is
address@hidden if fonts of that family are fixed-pitch.
address@hidden defun
-
address@hidden font-list-limit
-This variable specifies maximum number of fonts to consider in font
-matching. The function @code{x-family-fonts} will not return more than
-that many fonts, and font selection will consider only that many fonts
-when searching a matching font for face attributes. The default is
-currently 100.
address@hidden defvar
-
address@hidden Fontsets
address@hidden Fontsets
-
- A @dfn{fontset} is a list of fonts, each assigned to a range of
-character codes. An individual font cannot display the whole range of
-characters that Emacs supports, but a fontset can. Fontsets have names,
-just as fonts do, and you can use a fontset name in place of a font name
-when you specify the ``font'' for a frame or a face. Here is
-information about defining a fontset under Lisp program control.
-
address@hidden create-fontset-from-fontset-spec fontset-spec &optional
style-variant-p noerror
-This function defines a new fontset according to the specification
-string @var{fontset-spec}. The string should have this format:
-
address@hidden
address@hidden, @address@hidden:@address@hidden@dots{}}
address@hidden smallexample
-
address@hidden
-Whitespace characters before and after the commas are ignored.
-
-The first part of the string, @var{fontpattern}, should have the form of
-a standard X font name, except that the last two fields should be
address@hidden@var{alias}}.
-
-The new fontset has two names, one long and one short. The long name is
address@hidden in its entirety. The short name is
address@hidden@var{alias}}. You can refer to the fontset by either
-name. If a fontset with the same name already exists, an error is
-signaled, unless @var{noerror} is address@hidden, in which case this
-function does nothing.
-
-If optional argument @var{style-variant-p} is address@hidden, that says
-to create bold, italic and bold-italic variants of the fontset as well.
-These variant fontsets do not have a short name, only a long one, which
-is made by altering @var{fontpattern} to indicate the bold or italic
-status.
-
-The specification string also says which fonts to use in the fontset.
-See below for the details.
address@hidden defun
-
- The construct @address@hidden:@var{font}} specifies which font to
-use (in this fontset) for one particular character set. Here,
address@hidden is the name of a character set, and @var{font} is the font
-to use for that character set. You can use this construct any number of
-times in the specification string.
-
- For the remaining character sets, those that you don't specify
-explicitly, Emacs chooses a font based on @var{fontpattern}: it replaces
address@hidden@var{alias}} with a value that names one character set.
-For the @acronym{ASCII} character set, @address@hidden is replaced
-with @samp{ISO8859-1}.
-
- In addition, when several consecutive fields are wildcards, Emacs
-collapses them into a single wildcard. This is to prevent use of
-auto-scaled fonts. Fonts made by scaling larger fonts are not usable
-for editing, and scaling a smaller font is not useful because it is
-better to use the smaller font in its own size, which Emacs does.
-
- Thus if @var{fontpattern} is this,
-
address@hidden
--*-fixed-medium-r-normal-*-24-*-*-*-*-*-fontset-24
address@hidden example
-
address@hidden
-the font specification for @acronym{ASCII} characters would be this:
-
address@hidden
--*-fixed-medium-r-normal-*-24-*-ISO8859-1
address@hidden example
-
address@hidden
-and the font specification for Chinese GB2312 characters would be this:
-
address@hidden
--*-fixed-medium-r-normal-*-24-*-gb2312*-*
address@hidden example
-
- You may not have any Chinese font matching the above font
-specification. Most X distributions include only Chinese fonts that
-have @samp{song ti} or @samp{fangsong ti} in the @var{family} field. In
-such a case, @address@hidden can be specified as below:
-
address@hidden
-Emacs.Fontset-0: -*-fixed-medium-r-normal-*-24-*-*-*-*-*-fontset-24,\
- chinese-gb2312:-*-*-medium-r-normal-*-24-*-gb2312*-*
address@hidden smallexample
-
address@hidden
-Then, the font specifications for all but Chinese GB2312 characters have
address@hidden in the @var{family} field, and the font specification for
-Chinese GB2312 characters has a wild card @samp{*} in the @var{family}
-field.
-
address@hidden set-fontset-font name character fontname &optional frame
-This function modifies the existing fontset @var{name} to
-use the font name @var{fontname} for the character @var{character}.
-
-If @var{name} is @code{nil}, this function modifies the default
-fontset, whose short name is @samp{fontset-default}.
-
address@hidden may be a cons; @code{(@var{from} . @var{to})}, where
address@hidden and @var{to} are non-generic characters. In that case, use
address@hidden for all characters in the range @var{from} and @var{to}
-(inclusive).
-
address@hidden may be a charset. In that case, use
address@hidden for all character in the charsets.
-
address@hidden may be a cons; @code{(@var{family} . @var{registry})},
-where @var{family} is a family name of a font (possibly including a
-foundry name at the head), @var{registry} is a registry name of a font
-(possibly including an encoding name at the tail).
-
-For instance, this changes the default fontset to use a font of which
-registry name is @samp{JISX0208.1983} for all characters belonging to
-the charset @code{japanese-jisx0208}.
-
address@hidden
-(set-fontset-font nil 'japanese-jisx0208 '(nil . "JISX0208.1983"))
address@hidden smallexample
address@hidden defun
-
address@hidden char-displayable-p char
-This function returns @code{t} if Emacs ought to be able to display
address@hidden More precisely, if the selected frame's fontset has a
-font to display the character set that @var{char} belongs to.
-
-Fontsets can specify a font on a per-character basis; when the fontset
-does that, this function's value may not be accurate.
address@hidden defun
-
address@hidden Fringes
address@hidden Fringes
address@hidden fringes
-
- The @dfn{fringes} of a window are thin vertical strips down the
-sides that are used for displaying bitmaps that indicate truncation,
-continuation, horizontal scrolling, and the overlay arrow.
-
address@hidden
-* Fringe Size/Pos:: Specifying where to put the window fringes.
-* Fringe Indicators:: Displaying indicator icons in the window fringes.
-* Fringe Cursors:: Displaying cursors in the right fringe.
-* Fringe Bitmaps:: Specifying bitmaps for fringe indicators.
-* Customizing Bitmaps:: Specifying your own bitmaps to use in the fringes.
-* Overlay Arrow:: Display of an arrow to indicate position.
address@hidden menu
-
address@hidden Fringe Size/Pos
address@hidden Fringe Size and Position
-
- The following buffer-local variables control the position and width
-of the window fringes.
-
address@hidden fringes-outside-margins
-The fringes normally appear between the display margins and the window
-text. If the value is address@hidden, they appear outside the display
-margins. @xref{Display Margins}.
address@hidden defvar
-
address@hidden left-fringe-width
-This variable, if address@hidden, specifies the width of the left
-fringe in pixels. A value of @code{nil} means to use the left fringe
-width from the window's frame.
address@hidden defvar
-
address@hidden right-fringe-width
-This variable, if address@hidden, specifies the width of the right
-fringe in pixels. A value of @code{nil} means to use the right fringe
-width from the window's frame.
address@hidden defvar
-
- The values of these variables take effect when you display the
-buffer in a window. If you change them while the buffer is visible,
-you can call @code{set-window-buffer} to display it once again in the
-same window, to make the changes take effect.
-
address@hidden set-window-fringes window left &optional right outside-margins
-This function sets the fringe widths of window @var{window}.
-If @var{window} is @code{nil}, the selected window is used.
-
-The argument @var{left} specifies the width in pixels of the left
-fringe, and likewise @var{right} for the right fringe. A value of
address@hidden for either one stands for the default width. If
address@hidden is address@hidden, that specifies that fringes
-should appear outside of the display margins.
address@hidden defun
-
address@hidden window-fringes &optional window
-This function returns information about the fringes of a window
address@hidden If @var{window} is omitted or @code{nil}, the selected
-window is used. The value has the form @code{(@var{left-width}
address@hidden @var{outside-margins})}.
address@hidden defun
-
-
address@hidden Fringe Indicators
address@hidden Fringe Indicators
address@hidden fringe indicators
address@hidden indicators, fringe
-
- The @dfn{fringe indicators} are tiny icons Emacs displays in the
-window fringe (on a graphic display) to indicate truncated or
-continued lines, buffer boundaries, overlay arrow, etc.
-
address@hidden indicate-empty-lines
address@hidden fringes, and empty line indication
-When this is address@hidden, Emacs displays a special glyph in the
-fringe of each empty line at the end of the buffer, on graphical
-displays. @xref{Fringes}. This variable is automatically
-buffer-local in every buffer.
address@hidden defopt
-
address@hidden indicate-buffer-boundaries
-This buffer-local variable controls how the buffer boundaries and
-window scrolling are indicated in the window fringes.
-
-Emacs can indicate the buffer boundaries---that is, the first and last
-line in the buffer---with angle icons when they appear on the screen.
-In addition, Emacs can display an up-arrow in the fringe to show
-that there is text above the screen, and a down-arrow to show
-there is text below the screen.
-
-There are three kinds of basic values:
-
address@hidden @asis
address@hidden @code{nil}
-Don't display any of these fringe icons.
address@hidden @code{left}
-Display the angle icons and arrows in the left fringe.
address@hidden @code{right}
-Display the angle icons and arrows in the right fringe.
address@hidden any non-alist
-Display the angle icons in the left fringe
-and don't display the arrows.
address@hidden table
-
-Otherwise the value should be an alist that specifies which fringe
-indicators to display and where. Each element of the alist should
-have the form @code{(@var{indicator} . @var{position})}. Here,
address@hidden is one of @code{top}, @code{bottom}, @code{up},
address@hidden, and @code{t} (which covers all the icons not yet
-specified), while @var{position} is one of @code{left}, @code{right}
-and @code{nil}.
-
-For example, @code{((top . left) (t . right))} places the top angle
-bitmap in left fringe, and the bottom angle bitmap as well as both
-arrow bitmaps in right fringe. To show the angle bitmaps in the left
-fringe, and no arrow bitmaps, use @code{((top . left) (bottom . left))}.
address@hidden defvar
-
address@hidden default-indicate-buffer-boundaries
-The value of this variable is the default value for
address@hidden in buffers that do not override it.
address@hidden defvar
-
address@hidden fringe-indicator-alist
-This buffer-local variable specifies the mapping from logical fringe
-indicators to the actual bitmaps displayed in the window fringes.
-
-These symbols identify the logical fringe indicators:
-
address@hidden @asis
address@hidden Truncation and continuation line indicators:
address@hidden, @code{continuation}.
-
address@hidden Buffer position indicators:
address@hidden, @code{down},
address@hidden, @code{bottom},
address@hidden
-
address@hidden Empty line indicator:
address@hidden
-
address@hidden Overlay arrow indicator:
address@hidden
-
address@hidden Unknown bitmap indicator:
address@hidden
address@hidden table
-
- The value is an alist where each element @code{(@var{indicator} .
@var{bitmaps})}
-specifies the fringe bitmaps used to display a specific logical
-fringe indicator.
-
-Here, @var{indicator} specifies the logical indicator type, and
address@hidden is list of symbols @code{(@var{left} @var{right}
address@hidden @var{right1}])} which specifies the actual bitmap shown
-in the left or right fringe for the logical indicator.
-
-The @var{left} and @var{right} symbols specify the bitmaps shown in
-the left and/or right fringe for the specific indicator. The
address@hidden or @var{right1} bitmaps are used only for the `bottom' and
-`top-bottom indicators when the last (only) line in has no final
-newline. Alternatively, @var{bitmaps} may be a single symbol which is
-used in both left and right fringes.
-
-When @code{fringe-indicator-alist} has a buffer-local value, and there
-is no bitmap defined for a logical indicator, or the bitmap is
address@hidden, the corresponding value from the (non-local)
address@hidden is used.
-
-To completely hide a specific indicator, set the bitmap to @code{nil}.
address@hidden defvar
-
address@hidden default-fringe-indicator-alist
-The value of this variable is the default value for
address@hidden in buffers that do not override it.
address@hidden defvar
-
-Standard fringe bitmaps for indicators:
address@hidden
-left-arrow right-arrow up-arrow down-arrow
-left-curly-arrow right-curly-arrow
-left-triangle right-triangle
-top-left-angle top-right-angle
-bottom-left-angle bottom-right-angle
-left-bracket right-bracket
-filled-rectangle hollow-rectangle
-filled-square hollow-square
-vertical-bar horizontal-bar
-empty-line question-mark
address@hidden example
-
address@hidden Fringe Cursors
address@hidden Fringe Cursors
address@hidden fringe cursors
address@hidden cursor, fringe
-
- When a line is exactly as wide as the window, Emacs displays the
-cursor in the right fringe instead of using two lines. Different
-bitmaps are used to represent the cursor in the fringe depending on
-the current buffer's cursor type.
-
address@hidden @asis
address@hidden Logical cursor types:
address@hidden , @code{hollow}, @code{bar},
address@hidden, @code{hollow-small}.
address@hidden table
-
-The @code{hollow-small} type is used instead of @code{hollow} when the
-normal @code{hollow-rectangle} bitmap is too tall to fit on a specific
-display line.
-
address@hidden overflow-newline-into-fringe
-If this is address@hidden, lines exactly as wide as the window (not
-counting the final newline character) are not continued. Instead,
-when point is at the end of the line, the cursor appears in the right
-fringe.
address@hidden defvar
-
address@hidden fringe-cursor-alist
-This variable specifies the mapping from logical cursor type to the
-actual fringe bitmaps displayed in the right fringe. The value is an
-alist where each element @code{(@var{cursor} . @var{bitmap})} specifies
-the fringe bitmaps used to display a specific logical cursor type in
-the fringe. Here, @var{cursor} specifies the logical cursor type and
address@hidden is a symbol specifying the fringe bitmap to be displayed
-for that logical cursor type.
-
-When @code{fringe-cursor-alist} has a buffer-local value, and there is
-no bitmap defined for a cursor type, the corresponding value from the
-(non-local) @code{default-fringes-indicator-alist} is used.
address@hidden defvar
-
address@hidden default-fringes-cursor-alist
-The value of this variable is the default value for
address@hidden in buffers that do not override it.
address@hidden defvar
-
-Standard bitmaps for displaying the cursor in right fringe:
address@hidden
-filled-rectangle hollow-rectangle filled-square hollow-square
-vertical-bar horizontal-bar
address@hidden example
-
-
address@hidden Fringe Bitmaps
address@hidden Fringe Bitmaps
address@hidden fringe bitmaps
address@hidden bitmaps, fringe
-
- The @dfn{fringe bitmaps} are the actual bitmaps which represent the
-logical fringe indicators for truncated or continued lines, buffer
-boundaries, overlay arrow, etc. Fringe bitmap symbols have their own
-name space. The fringe bitmaps are shared by all frames and windows.
-You can redefine the built-in fringe bitmaps, and you can define new
-fringe bitmaps.
-
- The way to display a bitmap in the left or right fringes for a given
-line in a window is by specifying the @code{display} property for one
-of the characters that appears in it. Use a display specification of
-the form @code{(left-fringe @var{bitmap} address@hidden)} or
address@hidden(right-fringe @var{bitmap} address@hidden)} (@pxref{Display
-Property}). Here, @var{bitmap} is a symbol identifying the bitmap you
-want, and @var{face} (which is optional) is the name of the face whose
-colors should be used for displaying the bitmap, instead of the
-default @code{fringe} face. @var{face} is automatically merged with
-the @code{fringe} face, so normally @var{face} need only specify the
-foreground color for the bitmap.
-
address@hidden fringe-bitmaps-at-pos &optional pos window
-This function returns the fringe bitmaps of the display line
-containing position @var{pos} in window @var{window}. The return
-value has the form @code{(@var{left} @var{right} @var{ov})}, where @var{left}
-is the symbol for the fringe bitmap in the left fringe (or @code{nil}
-if no bitmap), @var{right} is similar for the right fringe, and @var{ov}
-is address@hidden if there is an overlay arrow in the left fringe.
-
-The value is @code{nil} if @var{pos} is not visible in @var{window}.
-If @var{window} is @code{nil}, that stands for the selected window.
-If @var{pos} is @code{nil}, that stands for the value of point in
address@hidden
address@hidden defun
-
address@hidden Customizing Bitmaps
address@hidden Customizing Fringe Bitmaps
-
address@hidden define-fringe-bitmap bitmap bits &optional height width align
-This function defines the symbol @var{bitmap} as a new fringe bitmap,
-or replaces an existing bitmap with that name.
-
-The argument @var{bits} specifies the image to use. It should be
-either a string or a vector of integers, where each element (an
-integer) corresponds to one row of the bitmap. Each bit of an integer
-corresponds to one pixel of the bitmap, where the low bit corresponds
-to the rightmost pixel of the bitmap.
-
-The height is normally the length of @var{bits}. However, you
-can specify a different height with address@hidden @var{height}. The width
-is normally 8, but you can specify a different width with address@hidden
address@hidden The width must be an integer between 1 and 16.
-
-The argument @var{align} specifies the positioning of the bitmap
-relative to the range of rows where it is used; the default is to
-center the bitmap. The allowed values are @code{top}, @code{center},
-or @code{bottom}.
-
-The @var{align} argument may also be a list @code{(@var{align}
address@hidden)} where @var{align} is interpreted as described above.
-If @var{periodic} is address@hidden, it specifies that the rows in
address@hidden should be repeated enough times to reach the specified
-height.
address@hidden defun
-
address@hidden destroy-fringe-bitmap bitmap
-This function destroy the fringe bitmap identified by @var{bitmap}.
-If @var{bitmap} identifies a standard fringe bitmap, it actually
-restores the standard definition of that bitmap, instead of
-eliminating it entirely.
address@hidden defun
-
address@hidden set-fringe-bitmap-face bitmap &optional face
-This sets the face for the fringe bitmap @var{bitmap} to @var{face}.
-If @var{face} is @code{nil}, it selects the @code{fringe} face. The
-bitmap's face controls the color to draw it in.
-
address@hidden is merged with the @code{fringe} face, so normally
address@hidden should specify only the foreground color.
address@hidden defun
-
address@hidden Overlay Arrow
address@hidden The Overlay Arrow
address@hidden @cindex overlay arrow Duplicates variable names
-
- The @dfn{overlay arrow} is useful for directing the user's attention
-to a particular line in a buffer. For example, in the modes used for
-interface to debuggers, the overlay arrow indicates the line of code
-about to be executed. This feature has nothing to do with
address@hidden (@pxref{Overlays}).
-
address@hidden overlay-arrow-string
-This variable holds the string to display to call attention to a
-particular line, or @code{nil} if the arrow feature is not in use.
-On a graphical display the contents of the string are ignored; instead a
-glyph is displayed in the fringe area to the left of the display area.
address@hidden defvar
-
address@hidden overlay-arrow-position
-This variable holds a marker that indicates where to display the overlay
-arrow. It should point at the beginning of a line. On a non-graphical
-display the arrow text
-appears at the beginning of that line, overlaying any text that would
-otherwise appear. Since the arrow is usually short, and the line
-usually begins with indentation, normally nothing significant is
-overwritten.
-
-The overlay-arrow string is displayed in any given buffer if the value
-of @code{overlay-arrow-position} in that buffer points into that
-buffer. Thus, it is possible to display multiple overlay arrow strings
-by creating buffer-local bindings of @code{overlay-arrow-position}.
-However, it is usually cleaner to use
address@hidden to achieve this result.
address@hidden !!! overlay-arrow-position: but the overlay string may remain in
the display
address@hidden of some other buffer until an update is required. This should
be fixed
address@hidden now. Is it?
address@hidden defvar
-
- You can do a similar job by creating an overlay with a
address@hidden property. @xref{Overlay Properties}.
-
- You can define multiple overlay arrows via the variable
address@hidden
-
address@hidden overlay-arrow-variable-list
-This variable's value is a list of variables, each of which specifies
-the position of an overlay arrow. The variable
address@hidden has its normal meaning because it is on
-this list.
address@hidden defvar
-
-Each variable on this list can have properties
address@hidden and @code{overlay-arrow-bitmap} that
-specify an overlay arrow string (for text-only terminals) or fringe
-bitmap (for graphical terminals) to display at the corresponding
-overlay arrow position. If either property is not set, the default
address@hidden or @code{overlay-arrow} fringe indicator
-is used.
-
address@hidden Scroll Bars
address@hidden Scroll Bars
address@hidden scroll bars
-
-Normally the frame parameter @code{vertical-scroll-bars} controls
-whether the windows in the frame have vertical scroll bars, and
-whether they are on the left or right. The frame parameter
address@hidden specifies how wide they are (@code{nil}
-meaning the default). @xref{Layout Parameters}.
-
address@hidden frame-current-scroll-bars &optional frame
-This function reports the scroll bar type settings for frame
address@hidden The value is a cons cell
address@hidden(@var{vertical-type} .@: @var{horizontal-type})}, where
address@hidden is either @code{left}, @code{right}, or @code{nil}
-(which means no scroll bar.) @var{horizontal-type} is meant to
-specify the horizontal scroll bar type, but since they are not
-implemented, it is always @code{nil}.
address@hidden defun
-
address@hidden vertical-scroll-bar
- You can enable or disable scroll bars for a particular buffer,
-by setting the variable @code{vertical-scroll-bar}. This variable
-automatically becomes buffer-local when set. The possible values are
address@hidden, @code{right}, @code{t}, which means to use the
-frame's default, and @code{nil} for no scroll bar.
-
- You can also control this for individual windows. Call the function
address@hidden to specify what to do for a specific window:
-
address@hidden set-window-scroll-bars window width &optional vertical-type
horizontal-type
-This function sets the width and type of scroll bars for window
address@hidden
-
address@hidden specifies the scroll bar width in pixels (@code{nil} means
-use the width specified for the frame). @var{vertical-type} specifies
-whether to have a vertical scroll bar and, if so, where. The possible
-values are @code{left}, @code{right} and @code{nil}, just like the
-values of the @code{vertical-scroll-bars} frame parameter.
-
-The argument @var{horizontal-type} is meant to specify whether and
-where to have horizontal scroll bars, but since they are not
-implemented, it has no effect. If @var{window} is @code{nil}, the
-selected window is used.
address@hidden defun
-
address@hidden window-scroll-bars &optional window
-Report the width and type of scroll bars specified for @var{window}.
-If @var{window} is omitted or @code{nil}, the selected window is used.
-The value is a list of the form @code{(@var{width}
address@hidden @var{vertical-type} @var{horizontal-type})}. The value
address@hidden is the value that was specified for the width (which may
-be @code{nil}); @var{cols} is the number of columns that the scroll
-bar actually occupies.
-
address@hidden is not actually meaningful.
address@hidden defun
-
-If you don't specify these values for a window with
address@hidden, the buffer-local variables
address@hidden and @code{scroll-bar-width} in the buffer being
-displayed control the window's vertical scroll bars. The function
address@hidden examines these variables. If you change them
-in a buffer that is already visible in a window, you can make the
-window take note of the new values by calling @code{set-window-buffer}
-specifying the same buffer that is already displayed.
-
address@hidden scroll-bar-mode
-This variable, always local in all buffers, controls whether and where
-to put scroll bars in windows displaying the buffer. The possible values
-are @code{nil} for no scroll bar, @code{left} to put a scroll bar on
-the left, and @code{right} to put a scroll bar on the right.
address@hidden defvar
-
address@hidden window-current-scroll-bars &optional window
-This function reports the scroll bar type for window @var{window}.
-If @var{window} is omitted or @code{nil}, the selected window is used.
-The value is a cons cell
address@hidden(@var{vertical-type} .@: @var{horizontal-type})}. Unlike
address@hidden, this reports the scroll bar type actually
-used, once frame defaults and @code{scroll-bar-mode} are taken into
-account.
address@hidden defun
-
address@hidden scroll-bar-width
-This variable, always local in all buffers, specifies the width of the
-buffer's scroll bars, measured in pixels. A value of @code{nil} means
-to use the value specified by the frame.
address@hidden defvar
-
address@hidden Display Property
address@hidden The @code{display} Property
address@hidden display specification
address@hidden display @r{(text property)}
-
- The @code{display} text property (or overlay property) is used to
-insert images into text, and also control other aspects of how text
-displays. The value of the @code{display} property should be a
-display specification, or a list or vector containing several display
-specifications.
-
- Some kinds of @code{display} properties specify something to display
-instead of the text that has the property. In this case, ``the text''
-means all the consecutive characters that have the same Lisp object as
-their @code{display} property; these characters are replaced as a
-single unit. By contrast, characters that have similar but distinct
-Lisp objects as their @code{display} properties are handled
-separately. Here's a function that illustrates this point:
-
address@hidden
-(defun foo ()
- (goto-char (point-min))
- (dotimes (i 5)
- (let ((string (concat "A")))
- (put-text-property (point) (1+ (point)) 'display string)
- (forward-char 1)
- (put-text-property (point) (1+ (point)) 'display string)
- (forward-char 1))))
address@hidden smallexample
-
address@hidden
-It gives each of the first ten characters in the buffer string
address@hidden"A"} as the @code{display} property, but they don't all get the
-same string. The first two characters get the same string, so they
-together are replaced with one @samp{A}. The next two characters get
-a second string, so they together are replaced with one @samp{A}.
-Likewise for each following pair of characters. Thus, the ten
-characters appear as five A's. This function would have the same
-results:
-
address@hidden
-(defun foo ()
- (goto-char (point-min))
- (dotimes (i 5)
- (let ((string (concat "A")))
- (put-text-property (point) (2+ (point)) 'display string)
- (put-text-property (point) (1+ (point)) 'display string)
- (forward-char 2))))
address@hidden smallexample
-
address@hidden
-This illustrates that what matters is the property value for
-each character. If two consecutive characters have the same
-object as the @code{display} property value, it's irrelevant
-whether they got this property from a single call to
address@hidden or from two different calls.
-
- The rest of this section describes several kinds of
-display specifications and what they mean.
-
address@hidden
-* Specified Space:: Displaying one space with a specified width.
-* Pixel Specification:: Specifying space width or height in pixels.
-* Other Display Specs:: Displaying an image; magnifying text; moving it
- up or down on the page; adjusting the width
- of spaces within text.
-* Display Margins:: Displaying text or images to the side of the main text.
address@hidden menu
-
address@hidden Specified Space
address@hidden Specified Spaces
address@hidden spaces, specified height or width
address@hidden variable-width spaces
-
- To display a space of specified width and/or height, use a display
-specification of the form @code{(space . @var{props})}, where
address@hidden is a property list (a list of alternating properties and
-values). You can put this property on one or more consecutive
-characters; a space of the specified height and width is displayed in
-place of @emph{all} of those characters. These are the properties you
-can use in @var{props} to specify the weight of the space:
-
address@hidden @code
address@hidden :width @var{width}
-If @var{width} is an integer or floating point number, it specifies
-that the space width should be @var{width} times the normal character
-width. @var{width} can also be a @dfn{pixel width} specification
-(@pxref{Pixel Specification}).
-
address@hidden :relative-width @var{factor}
-Specifies that the width of the stretch should be computed from the
-first character in the group of consecutive characters that have the
-same @code{display} property. The space width is the width of that
-character, multiplied by @var{factor}.
-
address@hidden :align-to @var{hpos}
-Specifies that the space should be wide enough to reach @var{hpos}.
-If @var{hpos} is a number, it is measured in units of the normal
-character width. @var{hpos} can also be a @dfn{pixel width}
-specification (@pxref{Pixel Specification}).
address@hidden table
-
- You should use one and only one of the above properties. You can
-also specify the height of the space, with these properties:
-
address@hidden @code
address@hidden :height @var{height}
-Specifies the height of the space.
-If @var{height} is an integer or floating point number, it specifies
-that the space height should be @var{height} times the normal character
-height. The @var{height} may also be a @dfn{pixel height} specification
-(@pxref{Pixel Specification}).
-
address@hidden :relative-height @var{factor}
-Specifies the height of the space, multiplying the ordinary height
-of the text having this display specification by @var{factor}.
-
address@hidden :ascent @var{ascent}
-If the value of @var{ascent} is a non-negative number no greater than
-100, it specifies that @var{ascent} percent of the height of the space
-should be considered as the ascent of the space---that is, the part
-above the baseline. The ascent may also be specified in pixel units
-with a @dfn{pixel ascent} specification (@pxref{Pixel Specification}).
-
address@hidden table
-
- Don't use both @code{:height} and @code{:relative-height} together.
-
- The @code{:width} and @code{:align-to} properties are supported on
-non-graphic terminals, but the other space properties in this section
-are not.
-
address@hidden Pixel Specification
address@hidden Pixel Specification for Spaces
address@hidden spaces, pixel specification
-
- The value of the @code{:width}, @code{:align-to}, @code{:height},
-and @code{:ascent} properties can be a special kind of expression that
-is evaluated during redisplay. The result of the evaluation is used
-as an absolute number of pixels.
-
- The following expressions are supported:
-
address@hidden
address@hidden
- @var{expr} ::= @var{num} | (@var{num}) | @var{unit} | @var{elem} | @var{pos}
| @var{image} | @var{form}
- @var{num} ::= @var{integer} | @var{float} | @var{symbol}
- @var{unit} ::= in | mm | cm | width | height
address@hidden group
address@hidden
- @var{elem} ::= left-fringe | right-fringe | left-margin | right-margin
- | scroll-bar | text
- @var{pos} ::= left | center | right
- @var{form} ::= (@var{num} . @var{expr}) | (@var{op} @var{expr} ...)
- @var{op} ::= + | -
address@hidden group
address@hidden smallexample
-
- The form @var{num} specifies a fraction of the default frame font
-height or width. The form @code{(@var{num})} specifies an absolute
-number of pixels. If @var{num} is a symbol, @var{symbol}, its
-buffer-local variable binding is used.
-
- The @code{in}, @code{mm}, and @code{cm} units specify the number of
-pixels per inch, millimeter, and centimeter, respectively. The
address@hidden and @code{height} units correspond to the default width
-and height of the current face. An image specification @code{image}
-corresponds to the width or height of the image.
-
- The @code{left-fringe}, @code{right-fringe}, @code{left-margin},
address@hidden, @code{scroll-bar}, and @code{text} elements
-specify to the width of the corresponding area of the window.
-
- The @code{left}, @code{center}, and @code{right} positions can be
-used with @code{:align-to} to specify a position relative to the left
-edge, center, or right edge of the text area.
-
- Any of the above window elements (except @code{text}) can also be
-used with @code{:align-to} to specify that the position is relative to
-the left edge of the given area. Once the base offset for a relative
-position has been set (by the first occurrence of one of these
-symbols), further occurrences of these symbols are interpreted as the
-width of the specified area. For example, to align to the center of
-the left-margin, use
-
address@hidden
-:align-to (+ left-margin (0.5 . left-margin))
address@hidden example
-
- If no specific base offset is set for alignment, it is always relative
-to the left edge of the text area. For example, @samp{:align-to 0} in a
-header-line aligns with the first text column in the text area.
-
- A value of the form @code{(@var{num} . @var{expr})} stands for the
-product of the values of @var{num} and @var{expr}. For example,
address@hidden(2 . in)} specifies a width of 2 inches, while @code{(0.5 .
address@hidden)} specifies half the width (or height) of the specified
-image.
-
- The form @code{(+ @var{expr} ...)} adds up the value of the
-expressions. The form @code{(- @var{expr} ...)} negates or subtracts
-the value of the expressions.
-
address@hidden Other Display Specs
address@hidden Other Display Specifications
-
- Here are the other sorts of display specifications that you can use
-in the @code{display} text property.
-
address@hidden @code
address@hidden @var{string}
-Display @var{string} instead of the text that has this property.
-
-Recursive display specifications are not address@hidden's
address@hidden properties, if any, are not used.
-
address@hidden (image . @var{image-props})
-This kind of display specification is an image descriptor (@pxref{Images}).
-When used as a display specification, it means to display the image
-instead of the text that has the display specification.
-
address@hidden (slice @var{x} @var{y} @var{width} @var{height})
-This specification together with @code{image} specifies a @dfn{slice}
-(a partial area) of the image to display. The elements @var{y} and
address@hidden specify the top left corner of the slice, within the image;
address@hidden and @var{height} specify the width and height of the
-slice. Integer values are numbers of pixels. A floating point number
-in the range 0.0--1.0 stands for that fraction of the width or height
-of the entire image.
-
address@hidden ((margin nil) @var{string})
-A display specification of this form means to display @var{string}
-instead of the text that has the display specification, at the same
-position as that text. It is equivalent to using just @var{string},
-but it is done as a special case of marginal display (@pxref{Display
-Margins}).
-
address@hidden (space-width @var{factor})
-This display specification affects all the space characters within the
-text that has the specification. It displays all of these spaces
address@hidden times as wide as normal. The element @var{factor} should
-be an integer or float. Characters other than spaces are not affected
-at all; in particular, this has no effect on tab characters.
-
address@hidden (height @var{height})
-This display specification makes the text taller or shorter.
-Here are the possibilities for @var{height}:
-
address@hidden @asis
address@hidden @code{(+ @var{n})}
-This means to use a font that is @var{n} steps larger. A ``step'' is
-defined by the set of available fonts---specifically, those that match
-what was otherwise specified for this text, in all attributes except
-height. Each size for which a suitable font is available counts as
-another step. @var{n} should be an integer.
-
address@hidden @code{(- @var{n})}
-This means to use a font that is @var{n} steps smaller.
-
address@hidden a number, @var{factor}
-A number, @var{factor}, means to use a font that is @var{factor} times
-as tall as the default font.
-
address@hidden a symbol, @var{function}
-A symbol is a function to compute the height. It is called with the
-current height as argument, and should return the new height to use.
-
address@hidden anything else, @var{form}
-If the @var{height} value doesn't fit the previous possibilities, it is
-a form. Emacs evaluates it to get the new height, with the symbol
address@hidden bound to the current specified font height.
address@hidden table
-
address@hidden (raise @var{factor})
-This kind of display specification raises or lowers the text
-it applies to, relative to the baseline of the line.
-
address@hidden must be a number, which is interpreted as a multiple of the
-height of the affected text. If it is positive, that means to display
-the characters raised. If it is negative, that means to display them
-lower down.
-
-If the text also has a @code{height} display specification, that does
-not affect the amount of raising or lowering, which is based on the
-faces used for the text.
address@hidden table
-
address@hidden We put all the address@hidden(when ...)}' on one line to
encourage
address@hidden makeinfo's end-of-sentence heuristics to DTRT. Previously, the
dot
address@hidden was at eol; the info file ended up w/ two spaces rendered after
it.
- You can make any display specification conditional. To do that,
-package it in another list of the form
address@hidden(when @var{condition} . @var{spec})}.
-Then the specification @var{spec} applies only when
address@hidden evaluates to a address@hidden value. During the
-evaluation, @code{object} is bound to the string or buffer having the
-conditional @code{display} property. @code{position} and
address@hidden are bound to the position within @code{object}
-and the buffer position where the @code{display} property was found,
-respectively. Both positions can be different when @code{object} is a
-string.
-
address@hidden Display Margins
address@hidden Displaying in the Margins
address@hidden display margins
address@hidden margins, display
-
- A buffer can have blank areas called @dfn{display margins} on the left
-and on the right. Ordinary text never appears in these areas, but you
-can put things into the display margins using the @code{display}
-property.
-
- To put text in the left or right display margin of the window, use a
-display specification of the form @code{(margin right-margin)} or
address@hidden(margin left-margin)} on it. To put an image in a display margin,
-use that display specification along with the display specification for
-the image. Unfortunately, there is currently no way to make
-text or images in the margin mouse-sensitive.
-
- If you put such a display specification directly on text in the
-buffer, the specified margin display appears @emph{instead of} that
-buffer text itself. To put something in the margin @emph{in
-association with} certain buffer text without preventing or altering
-the display of that text, put a @code{before-string} property on the
-text and put the display specification on the contents of the
-before-string.
-
- Before the display margins can display anything, you must give
-them a nonzero width. The usual way to do that is to set these
-variables:
-
address@hidden left-margin-width
-This variable specifies the width of the left margin.
-It is buffer-local in all buffers.
address@hidden defvar
-
address@hidden right-margin-width
-This variable specifies the width of the right margin.
-It is buffer-local in all buffers.
address@hidden defvar
-
- Setting these variables does not immediately affect the window. These
-variables are checked when a new buffer is displayed in the window.
-Thus, you can make changes take effect by calling
address@hidden
-
- You can also set the margin widths immediately.
-
address@hidden set-window-margins window left &optional right
-This function specifies the margin widths for window @var{window}.
-The argument @var{left} controls the left margin and
address@hidden controls the right margin (default @code{0}).
address@hidden defun
-
address@hidden window-margins &optional window
-This function returns the left and right margins of @var{window}
-as a cons cell of the form @code{(@var{left} . @var{right})}.
-If @var{window} is @code{nil}, the selected window is used.
address@hidden defun
-
address@hidden Images
address@hidden Images
address@hidden images in buffers
-
- To display an image in an Emacs buffer, you must first create an image
-descriptor, then use it as a display specifier in the @code{display}
-property of text that is displayed (@pxref{Display Property}).
-
- Emacs is usually able to display images when it is run on a
-graphical terminal. Images cannot be displayed in a text terminal, on
-certain graphical terminals that lack the support for this, or if
-Emacs is compiled without image support. You can use the function
address@hidden to determine if images can in principle be
-displayed (@pxref{Display Feature Testing}).
-
address@hidden
-* Image Formats:: Supported image formats.
-* Image Descriptors:: How to specify an image for use in @code{:display}.
-* XBM Images:: Special features for XBM format.
-* XPM Images:: Special features for XPM format.
-* GIF Images:: Special features for GIF format.
-* PostScript Images:: Special features for PostScript format.
-* Other Image Types:: Various other formats are supported.
-* Defining Images:: Convenient ways to define an image for later use.
-* Showing Images:: Convenient ways to display an image once it is defined.
-* Image Cache:: Internal mechanisms of image display.
address@hidden menu
-
address@hidden Image Formats
address@hidden Image Formats
address@hidden image formats
address@hidden image types
-
- Emacs can display a number of different image formats; some of them
-are supported only if particular support libraries are installed on
-your machine. In some environments, Emacs can load image
-libraries on demand; if so, the variable @code{image-library-alist}
-can be used to modify the set of known names for these dynamic
-libraries (though it is not possible to add new image formats).
-
- The supported image formats include XBM, XPM (this requires the
-libraries @code{libXpm} version 3.4k and @code{libz}), GIF (requiring
address@hidden 4.1.0), PostScript, PBM, JPEG (requiring the
address@hidden library version v6a), TIFF (requiring @code{libtiff}
-v3.4), PNG (requiring @code{libpng} 1.0.2), and SVG (requiring
address@hidden 2.0.0).
-
- You specify one of these formats with an image type symbol. The image
-type symbols are @code{xbm}, @code{xpm}, @code{gif}, @code{postscript},
address@hidden, @code{jpeg}, @code{tiff}, @code{png}, and @code{svg}.
-
address@hidden image-types
-This variable contains a list of those image type symbols that are
-potentially supported in the current configuration.
address@hidden here means that Emacs knows about the image types,
-not necessarily that they can be loaded (they could depend on
-unavailable dynamic libraries, for example).
-
-To know which image types are really available, use
address@hidden
address@hidden defvar
-
address@hidden image-library-alist
-This in an alist of image types vs external libraries needed to
-display them.
-
-Each element is a list @code{(@var{image-type} @var{library}...)},
-where the car is a supported image format from @code{image-types}, and
-the rest are strings giving alternate filenames for the corresponding
-external libraries to load.
-
-Emacs tries to load the libraries in the order they appear on the
-list; if none is loaded, the running session of Emacs won't support
-the image type. @code{pbm} and @code{xbm} don't need to be listed;
-they're always supported.
-
-This variable is ignored if the image libraries are statically linked
-into Emacs.
address@hidden defvar
-
address@hidden image-type-available-p type
-This function returns address@hidden if image type @var{type} is
-available, i.e., if images of this type can be loaded and displayed in
-Emacs. @var{type} should be one of the types contained in
address@hidden
-
-For image types whose support libraries are statically linked, this
-function always returns @code{t}; for other image types, it returns
address@hidden if the dynamic library could be loaded, @code{nil} otherwise.
address@hidden defun
-
address@hidden Image Descriptors
address@hidden Image Descriptors
address@hidden image descriptor
-
- An image description is a list of the form @code{(image . @var{props})},
-where @var{props} is a property list containing alternating keyword
-symbols (symbols whose names start with a colon) and their values.
-You can use any Lisp object as a property, but the only properties
-that have any special meaning are certain symbols, all of them keywords.
-
- Every image descriptor must contain the property @code{:type
address@hidden to specify the format of the image. The value of @var{type}
-should be an image type symbol; for example, @code{xpm} for an image in
-XPM format.
-
- Here is a list of other properties that are meaningful for all image
-types:
-
address@hidden @code
address@hidden :file @var{file}
-The @code{:file} property says to load the image from file
address@hidden If @var{file} is not an absolute file name, it is expanded
-in @code{data-directory}.
-
address@hidden :data @var{data}
-The @code{:data} property says the actual contents of the image.
-Each image must use either @code{:data} or @code{:file}, but not both.
-For most image types, the value of the @code{:data} property should be a
-string containing the image data; we recommend using a unibyte string.
-
-Before using @code{:data}, look for further information in the section
-below describing the specific image format. For some image types,
address@hidden:data} may not be supported; for some, it allows other data types;
-for some, @code{:data} alone is not enough, so you need to use other
-image properties along with @code{:data}.
-
address@hidden :margin @var{margin}
-The @code{:margin} property specifies how many pixels to add as an
-extra margin around the image. The value, @var{margin}, must be a
-non-negative number, or a pair @code{(@var{x} . @var{y})} of such
-numbers. If it is a pair, @var{x} specifies how many pixels to add
-horizontally, and @var{y} specifies how many pixels to add vertically.
-If @code{:margin} is not specified, the default is zero.
-
address@hidden :ascent @var{ascent}
-The @code{:ascent} property specifies the amount of the image's
-height to use for its ascent---that is, the part above the baseline.
-The value, @var{ascent}, must be a number in the range 0 to 100, or
-the symbol @code{center}.
-
-If @var{ascent} is a number, that percentage of the image's height is
-used for its ascent.
-
-If @var{ascent} is @code{center}, the image is vertically centered
-around a centerline which would be the vertical centerline of text drawn
-at the position of the image, in the manner specified by the text
-properties and overlays that apply to the image.
-
-If this property is omitted, it defaults to 50.
-
address@hidden :relief @var{relief}
-The @code{:relief} property, if address@hidden, adds a shadow rectangle
-around the image. The value, @var{relief}, specifies the width of the
-shadow lines, in pixels. If @var{relief} is negative, shadows are drawn
-so that the image appears as a pressed button; otherwise, it appears as
-an unpressed button.
-
address@hidden :conversion @var{algorithm}
-The @code{:conversion} property, if address@hidden, specifies a
-conversion algorithm that should be applied to the image before it is
-displayed; the value, @var{algorithm}, specifies which algorithm.
-
address@hidden @code
address@hidden laplace
address@hidden emboss
-Specifies the Laplace edge detection algorithm, which blurs out small
-differences in color while highlighting larger differences. People
-sometimes consider this useful for displaying the image for a
-``disabled'' button.
-
address@hidden (edge-detection :matrix @var{matrix} :color-adjust @var{adjust})
-Specifies a general edge-detection algorithm. @var{matrix} must be
-either a nine-element list or a nine-element vector of numbers. A pixel
-at position @math{x/y} in the transformed image is computed from
-original pixels around that position. @var{matrix} specifies, for each
-pixel in the neighborhood of @math{x/y}, a factor with which that pixel
-will influence the transformed pixel; element @math{0} specifies the
-factor for the pixel at @math{x-1/y-1}, element @math{1} the factor for
-the pixel at @math{x/y-1} etc., as shown below:
address@hidden
address@hidden
-$$\pmatrix{x-1/y-1 & x/y-1 & x+1/y-1 \cr
- x-1/y & x/y & x+1/y \cr
- x-1/y+1& x/y+1 & x+1/y+1 \cr}$$
address@hidden tex
address@hidden iftex
address@hidden
address@hidden
- (x-1/y-1 x/y-1 x+1/y-1
- x-1/y x/y x+1/y
- x-1/y+1 x/y+1 x+1/y+1)
address@hidden display
address@hidden ifnottex
-
-The resulting pixel is computed from the color intensity of the color
-resulting from summing up the RGB values of surrounding pixels,
-multiplied by the specified factors, and dividing that sum by the sum
-of the factors' absolute values.
-
-Laplace edge-detection currently uses a matrix of
address@hidden
address@hidden
-$$\pmatrix{1 & 0 & 0 \cr
- 0& 0 & 0 \cr
- 9 & 9 & -1 \cr}$$
address@hidden tex
address@hidden iftex
address@hidden
address@hidden
- (1 0 0
- 0 0 0
- 9 9 -1)
address@hidden display
address@hidden ifnottex
-
-Emboss edge-detection uses a matrix of
address@hidden
address@hidden
-$$\pmatrix{ 2 & -1 & 0 \cr
- -1 & 0 & 1 \cr
- 0 & 1 & -2 \cr}$$
address@hidden tex
address@hidden iftex
address@hidden
address@hidden
- ( 2 -1 0
- -1 0 1
- 0 1 -2)
address@hidden display
address@hidden ifnottex
-
address@hidden disabled
-Specifies transforming the image so that it looks ``disabled.''
address@hidden table
-
address@hidden :mask @var{mask}
-If @var{mask} is @code{heuristic} or @code{(heuristic @var{bg})}, build
-a clipping mask for the image, so that the background of a frame is
-visible behind the image. If @var{bg} is not specified, or if @var{bg}
-is @code{t}, determine the background color of the image by looking at
-the four corners of the image, assuming the most frequently occurring
-color from the corners is the background color of the image. Otherwise,
address@hidden must be a list @code{(@var{red} @var{green} @var{blue})}
-specifying the color to assume for the background of the image.
-
-If @var{mask} is @code{nil}, remove a mask from the image, if it has
-one. Images in some formats include a mask which can be removed by
-specifying @code{:mask nil}.
-
address@hidden :pointer @var{shape}
-This specifies the pointer shape when the mouse pointer is over this
-image. @xref{Pointer Shape}, for available pointer shapes.
-
address@hidden :map @var{map}
-This associates an image map of @dfn{hot spots} with this image.
-
-An image map is an alist where each element has the format
address@hidden(@var{area} @var{id} @var{plist})}. An @var{area} is specified
-as either a rectangle, a circle, or a polygon.
-
-A rectangle is a cons
address@hidden(rect . ((@var{x0} . @var{y0}) . (@var{x1} . @var{y1})))}
-which specifies the pixel coordinates of the upper left and bottom right
-corners of the rectangle area.
-
-A circle is a cons
address@hidden(circle . ((@var{x0} . @var{y0}) . @var{r}))}
-which specifies the center and the radius of the circle; @var{r} may
-be a float or integer.
-
-A polygon is a cons
address@hidden(poly . address@hidden @var{y0} @var{x1} @var{y1} ...])}
-where each pair in the vector describes one corner in the polygon.
-
-When the mouse pointer lies on a hot-spot area of an image, the
address@hidden of that hot-spot is consulted; if it contains a @code{help-echo}
-property, that defines a tool-tip for the hot-spot, and if it contains
-a @code{pointer} property, that defines the shape of the mouse cursor when
-it is on the hot-spot.
address@hidden Shape}, for available pointer shapes.
-
-When you click the mouse when the mouse pointer is over a hot-spot, an
-event is composed by combining the @var{id} of the hot-spot with the
-mouse event; for instance, @code{[area4 mouse-1]} if the hot-spot's
address@hidden is @code{area4}.
address@hidden table
-
address@hidden image-mask-p spec &optional frame
-This function returns @code{t} if image @var{spec} has a mask bitmap.
address@hidden is the frame on which the image will be displayed.
address@hidden @code{nil} or omitted means to use the selected frame
-(@pxref{Input Focus}).
address@hidden defun
-
address@hidden XBM Images
address@hidden XBM Images
address@hidden XBM
-
- To use XBM format, specify @code{xbm} as the image type. This image
-format doesn't require an external library, so images of this type are
-always supported.
-
- Additional image properties supported for the @code{xbm} image type are:
-
address@hidden @code
address@hidden :foreground @var{foreground}
-The value, @var{foreground}, should be a string specifying the image
-foreground color, or @code{nil} for the default color. This color is
-used for each pixel in the XBM that is 1. The default is the frame's
-foreground color.
-
address@hidden :background @var{background}
-The value, @var{background}, should be a string specifying the image
-background color, or @code{nil} for the default color. This color is
-used for each pixel in the XBM that is 0. The default is the frame's
-background color.
address@hidden table
-
- If you specify an XBM image using data within Emacs instead of an
-external file, use the following three properties:
-
address@hidden @code
address@hidden :data @var{data}
-The value, @var{data}, specifies the contents of the image.
-There are three formats you can use for @var{data}:
-
address@hidden @bullet
address@hidden
-A vector of strings or bool-vectors, each specifying one line of the
-image. Do specify @code{:height} and @code{:width}.
-
address@hidden
-A string containing the same byte sequence as an XBM file would contain.
-You must not specify @code{:height} and @code{:width} in this case,
-because omitting them is what indicates the data has the format of an
-XBM file. The file contents specify the height and width of the image.
-
address@hidden
-A string or a bool-vector containing the bits of the image (plus perhaps
-some extra bits at the end that will not be used). It should contain at
-least @var{width} * @code{height} bits. In this case, you must specify
address@hidden:height} and @code{:width}, both to indicate that the string
-contains just the bits rather than a whole XBM file, and to specify the
-size of the image.
address@hidden itemize
-
address@hidden :width @var{width}
-The value, @var{width}, specifies the width of the image, in pixels.
-
address@hidden :height @var{height}
-The value, @var{height}, specifies the height of the image, in pixels.
address@hidden table
-
address@hidden XPM Images
address@hidden XPM Images
address@hidden XPM
-
- To use XPM format, specify @code{xpm} as the image type. The
-additional image property @code{:color-symbols} is also meaningful with
-the @code{xpm} image type:
-
address@hidden @code
address@hidden :color-symbols @var{symbols}
-The value, @var{symbols}, should be an alist whose elements have the
-form @code{(@var{name} . @var{color})}. In each element, @var{name} is
-the name of a color as it appears in the image file, and @var{color}
-specifies the actual color to use for displaying that name.
address@hidden table
-
address@hidden GIF Images
address@hidden GIF Images
address@hidden GIF
-
- For GIF images, specify image type @code{gif}.
-
address@hidden @code
address@hidden :index @var{index}
-You can use @code{:index} to specify one image from a GIF file that
-contains more than one image. This property specifies use of image
-number @var{index} from the file. If the GIF file doesn't contain an
-image with index @var{index}, the image displays as a hollow box.
address@hidden table
-
address@hidden
-This could be used to implement limited support for animated GIFs.
-For example, the following function displays a multi-image GIF file
-at point-min in the current buffer, switching between sub-images
-every 0.1 seconds.
-
-(defun show-anim (file max)
- "Display multi-image GIF file FILE which contains MAX subimages."
- (display-anim (current-buffer) file 0 max t))
-
-(defun display-anim (buffer file idx max first-time)
- (when (= idx max)
- (setq idx 0))
- (let ((img (create-image file nil :image idx)))
- (save-excursion
- (set-buffer buffer)
- (goto-char (point-min))
- (unless first-time (delete-char 1))
- (insert-image img))
- (run-with-timer 0.1 nil 'display-anim buffer file (1+ idx) max nil)))
address@hidden ignore
-
address@hidden PostScript Images
address@hidden PostScript Images
address@hidden postscript images
-
- To use PostScript for an image, specify image type @code{postscript}.
-This works only if you have Ghostscript installed. You must always use
-these three properties:
-
address@hidden @code
address@hidden :pt-width @var{width}
-The value, @var{width}, specifies the width of the image measured in
-points (1/72 inch). @var{width} must be an integer.
-
address@hidden :pt-height @var{height}
-The value, @var{height}, specifies the height of the image in points
-(1/72 inch). @var{height} must be an integer.
-
address@hidden :bounding-box @var{box}
-The value, @var{box}, must be a list or vector of four integers, which
-specifying the bounding box of the PostScript image, analogous to the
address@hidden comment found in PostScript files.
-
address@hidden
-%%BoundingBox: 22 171 567 738
address@hidden example
address@hidden table
-
- Displaying PostScript images from Lisp data is not currently
-implemented, but it may be implemented by the time you read this.
-See the @file{etc/NEWS} file to make sure.
-
address@hidden Other Image Types
address@hidden Other Image Types
address@hidden PBM
-
- For PBM images, specify image type @code{pbm}. Color, gray-scale and
-monochromatic images are supported. For mono PBM images, two additional
-image properties are supported.
-
address@hidden @code
address@hidden :foreground @var{foreground}
-The value, @var{foreground}, should be a string specifying the image
-foreground color, or @code{nil} for the default color. This color is
-used for each pixel in the XBM that is 1. The default is the frame's
-foreground color.
-
address@hidden :background @var{background}
-The value, @var{background}, should be a string specifying the image
-background color, or @code{nil} for the default color. This color is
-used for each pixel in the XBM that is 0. The default is the frame's
-background color.
address@hidden table
-
- For JPEG images, specify image type @code{jpeg}.
-
- For TIFF images, specify image type @code{tiff}.
-
- For PNG images, specify image type @code{png}.
-
- For SVG images, specify image type @code{svg}.
-
address@hidden Defining Images
address@hidden Defining Images
-
- The functions @code{create-image}, @code{defimage} and
address@hidden provide convenient ways to create image descriptors.
-
address@hidden create-image file-or-data &optional type data-p &rest props
-This function creates and returns an image descriptor which uses the
-data in @var{file-or-data}. @var{file-or-data} can be a file name or
-a string containing the image data; @var{data-p} should be @code{nil}
-for the former case, address@hidden for the latter case.
-
-The optional argument @var{type} is a symbol specifying the image type.
-If @var{type} is omitted or @code{nil}, @code{create-image} tries to
-determine the image type from the file's first few bytes, or else
-from the file's name.
-
-The remaining arguments, @var{props}, specify additional image
-properties---for example,
-
address@hidden
-(create-image "foo.xpm" 'xpm nil :heuristic-mask t)
address@hidden example
-
-The function returns @code{nil} if images of this type are not
-supported. Otherwise it returns an image descriptor.
address@hidden defun
-
address@hidden defimage symbol specs &optional doc
-This macro defines @var{symbol} as an image name. The arguments
address@hidden is a list which specifies how to display the image.
-The third argument, @var{doc}, is an optional documentation string.
-
-Each argument in @var{specs} has the form of a property list, and each
-one should specify at least the @code{:type} property and either the
address@hidden:file} or the @code{:data} property. The value of @code{:type}
-should be a symbol specifying the image type, the value of
address@hidden:file} is the file to load the image from, and the value of
address@hidden:data} is a string containing the actual image data. Here is an
-example:
-
address@hidden
-(defimage test-image
- ((:type xpm :file "~/test1.xpm")
- (:type xbm :file "~/test1.xbm")))
address@hidden example
-
address@hidden tests each argument, one by one, to see if it is
-usable---that is, if the type is supported and the file exists. The
-first usable argument is used to make an image descriptor which is
-stored in @var{symbol}.
-
-If none of the alternatives will work, then @var{symbol} is defined
-as @code{nil}.
address@hidden defmac
-
address@hidden find-image specs
-This function provides a convenient way to find an image satisfying one
-of a list of image specifications @var{specs}.
-
-Each specification in @var{specs} is a property list with contents
-depending on image type. All specifications must at least contain the
-properties @code{:type @var{type}} and either @address@hidden:file @var{file}}}
-or @address@hidden:data @var{DATA}}}, where @var{type} is a symbol specifying
-the image type, e.g.@: @code{xbm}, @var{file} is the file to load the
-image from, and @var{data} is a string containing the actual image data.
-The first specification in the list whose @var{type} is supported, and
address@hidden exists, is used to construct the image specification to be
-returned. If no specification is satisfied, @code{nil} is returned.
-
-The image is looked for in @code{image-load-path}.
address@hidden defun
-
address@hidden image-load-path
-This variable's value is a list of locations in which to search for
-image files. If an element is a string or a variable symbol whose
-value is a string, the string is taken to be the name of a directory
-to search. If an element is a variable symbol whose value is a list,
-that is taken to be a list of directory names to search.
-
-The default is to search in the @file{images} subdirectory of the
-directory specified by @code{data-directory}, then the directory
-specified by @code{data-directory}, and finally in the directories in
address@hidden Subdirectories are not automatically included in
-the search, so if you put an image file in a subdirectory, you have to
-supply the subdirectory name explicitly. For example, to find the
-image @file{images/foo/bar.xpm} within @code{data-directory}, you
-should specify the image as follows:
-
address@hidden
-(defimage foo-image '((:type xpm :file "foo/bar.xpm")))
address@hidden example
address@hidden defvar
-
address@hidden image-load-path-for-library library image &optional path no-error
-This function returns a suitable search path for images used by the
-Lisp package @var{library}.
-
-The function searches for @var{image} first using @code{image-load-path},
-excluding @address@hidden/images}, and then in
address@hidden, followed by a path suitable for @var{library}, which
-includes @file{../../etc/images} and @file{../etc/images} relative to
-the library file itself, and finally in
address@hidden@code{data-directory}/images}.
-
-Then this function returns a list of directories which contains first
-the directory in which @var{image} was found, followed by the value of
address@hidden If @var{path} is given, it is used instead of
address@hidden
-
-If @var{no-error} is address@hidden and a suitable path can't be
-found, don't signal an error. Instead, return a list of directories as
-before, except that @code{nil} appears in place of the image directory.
-
-Here is an example that uses a common idiom to provide compatibility
-with versions of Emacs that lack the variable @code{image-load-path}:
-
address@hidden
-(defvar image-load-path) ; shush compiler
-(let* ((load-path (image-load-path-for-library
- "mh-e" "mh-logo.xpm"))
- (image-load-path (cons (car load-path)
- (when (boundp 'image-load-path)
- image-load-path))))
- (mh-tool-bar-folder-buttons-init))
address@hidden example
address@hidden defun
-
address@hidden Showing Images
address@hidden Showing Images
-
- You can use an image descriptor by setting up the @code{display}
-property yourself, but it is easier to use the functions in this
-section.
-
address@hidden insert-image image &optional string area slice
-This function inserts @var{image} in the current buffer at point. The
-value @var{image} should be an image descriptor; it could be a value
-returned by @code{create-image}, or the value of a symbol defined with
address@hidden The argument @var{string} specifies the text to put
-in the buffer to hold the image. If it is omitted or @code{nil},
address@hidden uses @code{" "} by default.
-
-The argument @var{area} specifies whether to put the image in a margin.
-If it is @code{left-margin}, the image appears in the left margin;
address@hidden specifies the right margin. If @var{area} is
address@hidden or omitted, the image is displayed at point within the
-buffer's text.
-
-The argument @var{slice} specifies a slice of the image to insert. If
address@hidden is @code{nil} or omitted the whole image is inserted.
-Otherwise, @var{slice} is a list @code{(@var{x} @var{y} @var{width}
address@hidden)} which specifies the @var{x} and @var{y} positions and
address@hidden and @var{height} of the image area to insert. Integer
-values are in units of pixels. A floating point number in the range
-0.0--1.0 stands for that fraction of the width or height of the entire
-image.
-
-Internally, this function inserts @var{string} in the buffer, and gives
-it a @code{display} property which specifies @var{image}. @xref{Display
-Property}.
address@hidden defun
-
address@hidden insert-sliced-image image &optional string area rows cols
-This function inserts @var{image} in the current buffer at point, like
address@hidden, but splits the image into @address@hidden
-equally sized slices.
address@hidden defun
-
address@hidden put-image image pos &optional string area
-This function puts image @var{image} in front of @var{pos} in the
-current buffer. The argument @var{pos} should be an integer or a
-marker. It specifies the buffer position where the image should appear.
-The argument @var{string} specifies the text that should hold the image
-as an alternative to the default.
-
-The argument @var{image} must be an image descriptor, perhaps returned
-by @code{create-image} or stored by @code{defimage}.
-
-The argument @var{area} specifies whether to put the image in a margin.
-If it is @code{left-margin}, the image appears in the left margin;
address@hidden specifies the right margin. If @var{area} is
address@hidden or omitted, the image is displayed at point within the
-buffer's text.
-
-Internally, this function creates an overlay, and gives it a
address@hidden property containing text that has a @code{display}
-property whose value is the image. (Whew!)
address@hidden defun
-
address@hidden remove-images start end &optional buffer
-This function removes images in @var{buffer} between positions
address@hidden and @var{end}. If @var{buffer} is omitted or @code{nil},
-images are removed from the current buffer.
-
-This removes only images that were put into @var{buffer} the way
address@hidden does it, not images that were inserted with
address@hidden or in other ways.
address@hidden defun
-
address@hidden image-size spec &optional pixels frame
-This function returns the size of an image as a pair
address@hidden@code{(@var{width} . @var{height})}}. @var{spec} is an image
-specification. @var{pixels} address@hidden means return sizes
-measured in pixels, otherwise return sizes measured in canonical
-character units (fractions of the width/height of the frame's default
-font). @var{frame} is the frame on which the image will be displayed.
address@hidden null or omitted means use the selected frame (@pxref{Input
-Focus}).
address@hidden defun
-
address@hidden max-image-size
-This variable is used to define the maximum size of image that Emacs
-will load. Emacs will refuse to load (and display) any image that is
-larger than this limit.
-
-If the value is an integer, it directly specifies the maximum
-image height and width, measured in pixels. If it is a floating
-point number, it specifies the maximum image height and width
-as a ratio to the frame height and width. If the value is
-non-numeric, there is no explicit limit on the size of images.
-
-The purpose of this variable is to prevent unreasonably large images
-from accidentally being loaded into Emacs. It only takes effect the
-first time an image is loaded. Once an image is placed in the image
-cache, it can always be displayed, even if the value of
address@hidden is subsequently changed (@pxref{Image Cache}).
address@hidden defvar
-
address@hidden Image Cache
address@hidden Image Cache
address@hidden image cache
-
- Emacs stores images in an image cache so that it can display them
-again more efficiently. When Emacs displays an image, it searches the
-image cache for an existing image specification @code{equal} to the
-desired specification. If a match is found, the image is displayed
-from the cache; otherwise, Emacs loads the image normally.
-
- Occasionally, you may need to tell Emacs to refresh the images
-associated with a given image specification. For example, suppose you
-display an image using a specification that contains a @code{:file}
-property. The image is loaded from the given file and stored in the
-image cache. If you later display the image again, using the same
-image specification, the image is displayed from the image cache.
-Normally, this is not a problem. However, if the image file has
-changed in the meantime, Emacs would be displaying the old version of
-the image. In such a situation, it is necessary to ``refresh'' the
-image using @code{image-refresh}.
-
address@hidden image-refresh spec &optional frame
-This function refreshes any images having image specifications
address@hidden to @var{spec} on frame @var{frame}. If @var{frame} is
address@hidden, the selected frame is used. If @var{frame} is @code{t},
-the refresh is applied to all existing frames.
-
-This works by removing all image with image specifications matching
address@hidden from the image cache. Thus, the next time the image is
-displayed, Emacs will load the image again.
address@hidden defun
-
address@hidden clear-image-cache &optional frame
-This function clears the entire image cache. If @var{frame} is
address@hidden, only the cache for that frame is cleared. Otherwise,
-all frames' caches are cleared.
address@hidden defun
-
-If an image in the image cache has not been displayed for a specified
-period of time, Emacs removes it from the cache and frees the
-associated memory.
-
address@hidden image-cache-eviction-delay
-This variable specifies the number of seconds an image can remain in the
-cache without being displayed. When an image is not displayed for this
-length of time, Emacs removes it from the image cache.
-
-If the value is @code{nil}, Emacs does not remove images from the cache
-except when you explicitly clear it. This mode can be useful for
-debugging.
address@hidden defvar
-
address@hidden Buttons
address@hidden Buttons
address@hidden buttons in buffers
address@hidden clickable buttons in buffers
-
- The @emph{button} package defines functions for inserting and
-manipulating clickable (with the mouse, or via keyboard commands)
-buttons in Emacs buffers, such as might be used for help hyper-links,
-etc. Emacs uses buttons for the hyper-links in help text and the like.
-
- A button is essentially a set of properties attached (via text
-properties or overlays) to a region of text in an Emacs buffer. These
-properties are called @dfn{button properties}.
-
- One of these properties (@code{action}) is a function, which will
-be called when the user invokes it using the keyboard or the mouse.
-The invoked function may then examine the button and use its other
-properties as desired.
-
- In some ways the Emacs button package duplicates functionality offered
-by the widget package (@pxref{Top, , Introduction, widget, The Emacs
-Widget Library}), but the button package has the advantage that it is
-much faster, much smaller, and much simpler to use (for elisp
-programmers---for users, the result is about the same). The extra
-speed and space savings are useful mainly if you need to create many
-buttons in a buffer (for instance an @code{*Apropos*} buffer uses
-buttons to make entries clickable, and may contain many thousands of
-entries).
-
address@hidden
-* Button Properties:: Button properties with special meanings.
-* Button Types:: Defining common properties for classes of buttons.
-* Making Buttons:: Adding buttons to Emacs buffers.
-* Manipulating Buttons:: Getting and setting properties of buttons.
-* Button Buffer Commands:: Buffer-wide commands and bindings for buttons.
address@hidden menu
-
address@hidden Button Properties
address@hidden Button Properties
address@hidden button properties
-
- Buttons have an associated list of properties defining their
-appearance and behavior, and other arbitrary properties may be used
-for application specific purposes. Some properties that have special
-meaning to the button package include:
-
address@hidden @code
address@hidden action
address@hidden action @r{(button property)}
-The function to call when the user invokes the button, which is passed
-the single argument @var{button}. By default this is @code{ignore},
-which does nothing.
-
address@hidden mouse-action
address@hidden mouse-action @r{(button property)}
-This is similar to @code{action}, and when present, will be used
-instead of @code{action} for button invocations resulting from
-mouse-clicks (instead of the user hitting @key{RET}). If not
-present, mouse-clicks use @code{action} instead.
-
address@hidden face
address@hidden face @r{(button property)}
-This is an Emacs face controlling how buttons of this type are
-displayed; by default this is the @code{button} face.
-
address@hidden mouse-face
address@hidden mouse-face @r{(button property)}
-This is an additional face which controls appearance during
-mouse-overs (merged with the usual button face); by default this is
-the usual Emacs @code{highlight} face.
-
address@hidden keymap
address@hidden keymap @r{(button property)}
-The button's keymap, defining bindings active within the button
-region. By default this is the usual button region keymap, stored
-in the variable @code{button-map}, which defines @key{RET} and
address@hidden to invoke the button.
-
address@hidden type
address@hidden type @r{(button property)}
-The button-type of the button. When creating a button, this is
-usually specified using the @code{:type} keyword argument.
address@hidden Types}.
-
address@hidden help-echo
address@hidden help-index @r{(button property)}
-A string displayed by the Emacs tool-tip help system; by default,
address@hidden"mouse-2, RET: Push this button"}.
-
address@hidden follow-link
address@hidden follow-link @r{(button property)}
-The follow-link property, defining how a @key{Mouse-1} click behaves
-on this button, @xref{Links and Mouse-1}.
-
address@hidden button
address@hidden button @r{(button property)}
-All buttons have a address@hidden @code{button} property, which may be useful
-in finding regions of text that comprise buttons (which is what the
-standard button functions do).
address@hidden table
-
- There are other properties defined for the regions of text in a
-button, but these are not generally interesting for typical uses.
-
address@hidden Button Types
address@hidden Button Types
address@hidden button types
-
- Every button has a button @emph{type}, which defines default values
-for the button's properties. Button types are arranged in a
-hierarchy, with specialized types inheriting from more general types,
-so that it's easy to define special-purpose types of buttons for
-specific tasks.
-
address@hidden define-button-type name &rest properties
-Define a `button type' called @var{name}. The remaining arguments
-form a sequence of @var{property value} pairs, specifying default
-property values for buttons with this type (a button's type may be set
-by giving it a @code{type} property when creating the button, using
-the @code{:type} keyword argument).
-
-In addition, the keyword argument @code{:supertype} may be used to
-specify a button-type from which @var{name} inherits its default
-property values. Note that this inheritance happens only when
address@hidden is defined; subsequent changes to a supertype are not
-reflected in its subtypes.
address@hidden defun
-
- Using @code{define-button-type} to define default properties for
-buttons is not necessary---buttons without any specified type use the
-built-in button-type @code{button}---but it is encouraged, since
-doing so usually makes the resulting code clearer and more efficient.
-
address@hidden Making Buttons
address@hidden Making Buttons
address@hidden making buttons
-
- Buttons are associated with a region of text, using an overlay or
-text properties to hold button-specific information, all of which are
-initialized from the button's type (which defaults to the built-in
-button type @code{button}). Like all Emacs text, the appearance of
-the button is governed by the @code{face} property; by default (via
-the @code{face} property inherited from the @code{button} button-type)
-this is a simple underline, like a typical web-page link.
-
- For convenience, there are two sorts of button-creation functions,
-those that add button properties to an existing region of a buffer,
-called @code{make-...button}, and those that also insert the button
-text, called @code{insert-...button}.
-
- The button-creation functions all take the @code{&rest} argument
address@hidden, which should be a sequence of @var{property value}
-pairs, specifying properties to add to the button; see @ref{Button
-Properties}. In addition, the keyword argument @code{:type} may be
-used to specify a button-type from which to inherit other properties;
-see @ref{Button Types}. Any properties not explicitly specified
-during creation will be inherited from the button's type (if the type
-defines such a property).
-
- The following functions add a button using an overlay
-(@pxref{Overlays}) to hold the button properties:
-
address@hidden make-button beg end &rest properties
-This makes a button from @var{beg} to @var{end} in the
-current buffer, and returns it.
address@hidden defun
-
address@hidden insert-button label &rest properties
-This insert a button with the label @var{label} at point,
-and returns it.
address@hidden defun
-
- The following functions are similar, but use Emacs text properties
-(@pxref{Text Properties}) to hold the button properties, making the
-button actually part of the text instead of being a property of the
-buffer. Buttons using text properties do not create markers into the
-buffer, which is important for speed when you use extremely large
-numbers of buttons. Both functions return the position of the start
-of the new button:
-
address@hidden make-text-button beg end &rest properties
-This makes a button from @var{beg} to @var{end} in the current buffer, using
-text properties.
address@hidden defun
-
address@hidden insert-text-button label &rest properties
-This inserts a button with the label @var{label} at point, using text
-properties.
address@hidden defun
-
address@hidden Manipulating Buttons
address@hidden Manipulating Buttons
address@hidden manipulating buttons
-
-These are functions for getting and setting properties of buttons.
-Often these are used by a button's invocation function to determine
-what to do.
-
-Where a @var{button} parameter is specified, it means an object
-referring to a specific button, either an overlay (for overlay
-buttons), or a buffer-position or marker (for text property buttons).
-Such an object is passed as the first argument to a button's
-invocation function when it is invoked.
-
address@hidden button-start button
-Return the position at which @var{button} starts.
address@hidden defun
-
address@hidden button-end button
-Return the position at which @var{button} ends.
address@hidden defun
-
address@hidden button-get button prop
-Get the property of button @var{button} named @var{prop}.
address@hidden defun
-
address@hidden button-put button prop val
-Set @var{button}'s @var{prop} property to @var{val}.
address@hidden defun
-
address@hidden button-activate button &optional use-mouse-action
-Call @var{button}'s @code{action} property (i.e., invoke it). If
address@hidden is address@hidden, try to invoke the button's
address@hidden property instead of @code{action}; if the button
-has no @code{mouse-action} property, use @code{action} as normal.
address@hidden defun
-
address@hidden button-label button
-Return @var{button}'s text label.
address@hidden defun
-
address@hidden button-type button
-Return @var{button}'s button-type.
address@hidden defun
-
address@hidden button-has-type-p button type
-Return @code{t} if @var{button} has button-type @var{type}, or one of
address@hidden's subtypes.
address@hidden defun
-
address@hidden button-at pos
-Return the button at position @var{pos} in the current buffer, or @code{nil}.
address@hidden defun
-
address@hidden button-type-put type prop val
-Set the button-type @var{type}'s @var{prop} property to @var{val}.
address@hidden defun
-
address@hidden button-type-get type prop
-Get the property of button-type @var{type} named @var{prop}.
address@hidden defun
-
address@hidden button-type-subtype-p type supertype
-Return @code{t} if button-type @var{type} is a subtype of @var{supertype}.
address@hidden defun
-
address@hidden Button Buffer Commands
address@hidden Button Buffer Commands
address@hidden button buffer commands
-
-These are commands and functions for locating and operating on
-buttons in an Emacs buffer.
-
address@hidden is the command that a user uses to actually `push'
-a button, and is bound by default in the button itself to @key{RET}
-and to @key{mouse-2} using a region-specific keymap. Commands
-that are useful outside the buttons itself, such as
address@hidden and @code{backward-button} are additionally
-available in the keymap stored in @code{button-buffer-map}; a mode
-which uses buttons may want to use @code{button-buffer-map} as a
-parent keymap for its keymap.
-
-If the button has a address@hidden @code{follow-link} property, and
address@hidden is set, a quick @key{Mouse-1} click
-will also activate the @code{push-button} command.
address@hidden and Mouse-1}.
-
address@hidden Command push-button &optional pos use-mouse-action
-Perform the action specified by a button at location @var{pos}.
address@hidden may be either a buffer position or a mouse-event. If
address@hidden is address@hidden, or @var{pos} is a
-mouse-event (@pxref{Mouse Events}), try to invoke the button's
address@hidden property instead of @code{action}; if the button
-has no @code{mouse-action} property, use @code{action} as normal.
address@hidden defaults to point, except when @code{push-button} is invoked
-interactively as the result of a mouse-event, in which case, the mouse
-event's position is used. If there's no button at @var{pos}, do
-nothing and return @code{nil}, otherwise return @code{t}.
address@hidden deffn
-
address@hidden Command forward-button n &optional wrap display-message
-Move to the @var{n}th next button, or @var{n}th previous button if
address@hidden is negative. If @var{n} is zero, move to the start of any
-button at point. If @var{wrap} is address@hidden, moving past either
-end of the buffer continues from the other end. If
address@hidden is address@hidden, the button's help-echo string
-is displayed. Any button with a address@hidden @code{skip} property
-is skipped over. Returns the button found.
address@hidden deffn
-
address@hidden Command backward-button n &optional wrap display-message
-Move to the @var{n}th previous button, or @var{n}th next button if
address@hidden is negative. If @var{n} is zero, move to the start of any
-button at point. If @var{wrap} is address@hidden, moving past either
-end of the buffer continues from the other end. If
address@hidden is address@hidden, the button's help-echo string
-is displayed. Any button with a address@hidden @code{skip} property
-is skipped over. Returns the button found.
address@hidden deffn
-
address@hidden next-button pos &optional count-current
address@hidden previous-button pos &optional count-current
-Return the next button after (for @code{next-button} or before (for
address@hidden) position @var{pos} in the current buffer. If
address@hidden is address@hidden, count any button at @var{pos}
-in the search, instead of starting at the next button.
address@hidden defun
-
address@hidden Abstract Display
address@hidden Abstract Display
address@hidden ewoc
address@hidden display, abstract
address@hidden display, arbitrary objects
address@hidden model/view/controller
address@hidden view part, model/view/controller
-
- The Ewoc package constructs buffer text that represents a structure
-of Lisp objects, and updates the text to follow changes in that
-structure. This is like the ``view'' component in the
-``model/view/controller'' design paradigm.
-
- An @dfn{ewoc} is a structure that organizes information required to
-construct buffer text that represents certain Lisp data. The buffer
-text of the ewoc has three parts, in order: first, fixed @dfn{header}
-text; next, textual descriptions of a series of data elements (Lisp
-objects that you specify); and last, fixed @dfn{footer} text.
-Specifically, an ewoc contains information on:
-
address@hidden @bullet
address@hidden
-The buffer which its text is generated in.
-
address@hidden
-The text's start position in the buffer.
-
address@hidden
-The header and footer strings.
-
address@hidden
-A doubly-linked chain of @dfn{nodes}, each of which contains:
-
address@hidden
address@hidden
-A @dfn{data element}, a single Lisp object.
-
address@hidden
-Links to the preceding and following nodes in the chain.
address@hidden itemize
-
address@hidden
-A @dfn{pretty-printer} function which is responsible for
-inserting the textual representation of a data
-element value into the current buffer.
address@hidden itemize
-
- Typically, you define an ewoc with @code{ewoc-create}, and then pass
-the resulting ewoc structure to other functions in the Ewoc package to
-build nodes within it, and display it in the buffer. Once it is
-displayed in the buffer, other functions determine the correspondance
-between buffer positions and nodes, move point from one node's textual
-representation to another, and so forth. @xref{Abstract Display
-Functions}.
-
- A node @dfn{encapsulates} a data element much the way a variable
-holds a value. Normally, encapsulation occurs as a part of adding a
-node to the ewoc. You can retrieve the data element value and place a
-new value in its place, like so:
-
address@hidden
-(ewoc-data @var{node})
address@hidden value
-
-(ewoc-set-data @var{node} @var{new-value})
address@hidden @var{new-value}
address@hidden lisp
-
address@hidden
-You can also use, as the data element value, a Lisp object (list or
-vector) that is a container for the ``real'' value, or an index into
-some other structure. The example (@pxref{Abstract Display Example})
-uses the latter approach.
-
- When the data changes, you will want to update the text in the
-buffer. You can update all nodes by calling @code{ewoc-refresh}, or
-just specific nodes using @code{ewoc-invalidate}, or all nodes
-satisfying a predicate using @code{ewoc-map}. Alternatively, you can
-delete invalid nodes using @code{ewoc-delete} or @code{ewoc-filter},
-and add new nodes in their place. Deleting a node from an ewoc deletes
-its associated textual description from buffer, as well.
-
address@hidden
-* Abstract Display Functions::
-* Abstract Display Example::
address@hidden menu
-
address@hidden Abstract Display Functions
address@hidden Abstract Display Functions
-
- In this subsection, @var{ewoc} and @var{node} stand for the
-structures described above (@pxref{Abstract Display}), while
address@hidden stands for an arbitrary Lisp object used as a data element.
-
address@hidden ewoc-create pretty-printer &optional header footer nosep
-This constructs and returns a new ewoc, with no nodes (and thus no data
-elements). @var{pretty-printer} should be a function that takes one
-argument, a data element of the sort you plan to use in this ewoc, and
-inserts its textual description at point using @code{insert} (and never
address@hidden, because that would interfere with the
-Ewoc package's internal mechanisms).
-
-Normally, a newline is automatically inserted after the header,
-the footer and every node's textual description. If @var{nosep}
-is address@hidden, no newline is inserted. This may be useful for
-displaying an entire ewoc on a single line, for example, or for
-making nodes ``invisible'' by arranging for @var{pretty-printer}
-to do nothing for those nodes.
-
-An ewoc maintains its text in the buffer that is current when
-you create it, so switch to the intended buffer before calling
address@hidden
address@hidden defun
-
address@hidden ewoc-buffer ewoc
-This returns the buffer where @var{ewoc} maintains its text.
address@hidden defun
-
address@hidden ewoc-get-hf ewoc
-This returns a cons cell @code{(@var{header} . @var{footer})}
-made from @var{ewoc}'s header and footer.
address@hidden defun
-
address@hidden ewoc-set-hf ewoc header footer
-This sets the header and footer of @var{ewoc} to the strings
address@hidden and @var{footer}, respectively.
address@hidden defun
-
address@hidden ewoc-enter-first ewoc data
address@hidden ewoc-enter-last ewoc data
-These add a new node encapsulating @var{data}, putting it, respectively,
-at the beginning or end of @var{ewoc}'s chain of nodes.
address@hidden defun
-
address@hidden ewoc-enter-before ewoc node data
address@hidden ewoc-enter-after ewoc node data
-These add a new node encapsulating @var{data}, adding it to
address@hidden before or after @var{node}, respectively.
address@hidden defun
-
address@hidden ewoc-prev ewoc node
address@hidden ewoc-next ewoc node
-These return, respectively, the previous node and the next node of @var{node}
-in @var{ewoc}.
address@hidden defun
-
address@hidden ewoc-nth ewoc n
-This returns the node in @var{ewoc} found at zero-based index @var{n}.
-A negative @var{n} means count from the end. @code{ewoc-nth} returns
address@hidden if @var{n} is out of range.
address@hidden defun
-
address@hidden ewoc-data node
-This extracts the data encapsulated by @var{node} and returns it.
address@hidden defun
-
address@hidden ewoc-set-data node data
-This sets the data encapsulated by @var{node} to @var{data}.
address@hidden defun
-
address@hidden ewoc-locate ewoc &optional pos guess
-This determines the node in @var{ewoc} which contains point (or
address@hidden if specified), and returns that node. If @var{ewoc} has no
-nodes, it returns @code{nil}. If @var{pos} is before the first node,
-it returns the first node; if @var{pos} is after the last node, it returns
-the last node. The optional third arg @var{guess}
-should be a node that is likely to be near @var{pos}; this doesn't
-alter the result, but makes the function run faster.
address@hidden defun
-
address@hidden ewoc-location node
-This returns the start position of @var{node}.
address@hidden defun
-
address@hidden ewoc-goto-prev ewoc arg
address@hidden ewoc-goto-next ewoc arg
-These move point to the previous or next, respectively, @var{arg}th node
-in @var{ewoc}. @code{ewoc-goto-prev} does not move if it is already at
-the first node or if @var{ewoc} is empty, whereas @code{ewoc-goto-next}
-moves past the last node, returning @code{nil}. Excepting this special
-case, these functions return the node moved to.
address@hidden defun
-
address@hidden ewoc-goto-node ewoc node
-This moves point to the start of @var{node} in @var{ewoc}.
address@hidden defun
-
address@hidden ewoc-refresh ewoc
-This function regenerates the text of @var{ewoc}. It works by
-deleting the text between the header and the footer, i.e., all the
-data elements' representations, and then calling the pretty-printer
-function for each node, one by one, in order.
address@hidden defun
-
address@hidden ewoc-invalidate ewoc &rest nodes
-This is similar to @code{ewoc-refresh}, except that only @var{nodes} in
address@hidden are updated instead of the entire set.
address@hidden defun
-
address@hidden ewoc-delete ewoc &rest nodes
-This deletes each node in @var{nodes} from @var{ewoc}.
address@hidden defun
-
address@hidden ewoc-filter ewoc predicate &rest args
-This calls @var{predicate} for each data element in @var{ewoc} and
-deletes those nodes for which @var{predicate} returns @code{nil}.
-Any @var{args} are passed to @var{predicate}.
address@hidden defun
-
address@hidden ewoc-collect ewoc predicate &rest args
-This calls @var{predicate} for each data element in @var{ewoc}
-and returns a list of those elements for which @var{predicate}
-returns address@hidden The elements in the list are ordered
-as in the buffer. Any @var{args} are passed to @var{predicate}.
address@hidden defun
-
address@hidden ewoc-map map-function ewoc &rest args
-This calls @var{map-function} for each data element in @var{ewoc} and
-updates those nodes for which @var{map-function} returns address@hidden
-Any @var{args} are passed to @var{map-function}.
address@hidden defun
-
address@hidden Abstract Display Example
address@hidden Abstract Display Example
-
- Here is a simple example using functions of the ewoc package to
-implement a ``color components display,'' an area in a buffer that
-represents a vector of three integers (itself representing a 24-bit RGB
-value) in various ways.
-
address@hidden
-(setq colorcomp-ewoc nil
- colorcomp-data nil
- colorcomp-mode-map nil
- colorcomp-labels ["Red" "Green" "Blue"])
-
-(defun colorcomp-pp (data)
- (if data
- (let ((comp (aref colorcomp-data data)))
- (insert (aref colorcomp-labels data) "\t: #x"
- (format "%02X" comp) " "
- (make-string (ash comp -2) ?#) "\n"))
- (let ((cstr (format "#%02X%02X%02X"
- (aref colorcomp-data 0)
- (aref colorcomp-data 1)
- (aref colorcomp-data 2)))
- (samp " (sample text) "))
- (insert "Color\t: "
- (propertize samp 'face `(foreground-color . ,cstr))
- (propertize samp 'face `(background-color . ,cstr))
- "\n"))))
-
-(defun colorcomp (color)
- "Allow fiddling with COLOR in a new buffer.
-The buffer is in Color Components mode."
- (interactive "sColor (name or #RGB or #RRGGBB): ")
- (when (string= "" color)
- (setq color "green"))
- (unless (color-values color)
- (error "No such color: %S" color))
- (switch-to-buffer
- (generate-new-buffer (format "originally: %s" color)))
- (kill-all-local-variables)
- (setq major-mode 'colorcomp-mode
- mode-name "Color Components")
- (use-local-map colorcomp-mode-map)
- (erase-buffer)
- (buffer-disable-undo)
- (let ((data (apply 'vector (mapcar (lambda (n) (ash n -8))
- (color-values color))))
- (ewoc (ewoc-create 'colorcomp-pp
- "\nColor Components\n\n"
- (substitute-command-keys
- "address@hidden@}"))))
- (set (make-local-variable 'colorcomp-data) data)
- (set (make-local-variable 'colorcomp-ewoc) ewoc)
- (ewoc-enter-last ewoc 0)
- (ewoc-enter-last ewoc 1)
- (ewoc-enter-last ewoc 2)
- (ewoc-enter-last ewoc nil)))
address@hidden example
-
address@hidden controller part, model/view/controller
- This example can be extended to be a ``color selection widget'' (in
-other words, the controller part of the ``model/view/controller''
-design paradigm) by defining commands to modify @code{colorcomp-data}
-and to ``finish'' the selection process, and a keymap to tie it all
-together conveniently.
-
address@hidden
-(defun colorcomp-mod (index limit delta)
- (let ((cur (aref colorcomp-data index)))
- (unless (= limit cur)
- (aset colorcomp-data index (+ cur delta)))
- (ewoc-invalidate
- colorcomp-ewoc
- (ewoc-nth colorcomp-ewoc index)
- (ewoc-nth colorcomp-ewoc -1))))
-
-(defun colorcomp-R-more () (interactive) (colorcomp-mod 0 255 1))
-(defun colorcomp-G-more () (interactive) (colorcomp-mod 1 255 1))
-(defun colorcomp-B-more () (interactive) (colorcomp-mod 2 255 1))
-(defun colorcomp-R-less () (interactive) (colorcomp-mod 0 0 -1))
-(defun colorcomp-G-less () (interactive) (colorcomp-mod 1 0 -1))
-(defun colorcomp-B-less () (interactive) (colorcomp-mod 2 0 -1))
-
-(defun colorcomp-copy-as-kill-and-exit ()
- "Copy the color components into the kill ring and kill the buffer.
-The string is formatted #RRGGBB (hash followed by six hex digits)."
- (interactive)
- (kill-new (format "#%02X%02X%02X"
- (aref colorcomp-data 0)
- (aref colorcomp-data 1)
- (aref colorcomp-data 2)))
- (kill-buffer nil))
-
-(setq colorcomp-mode-map
- (let ((m (make-sparse-keymap)))
- (suppress-keymap m)
- (define-key m "i" 'colorcomp-R-less)
- (define-key m "o" 'colorcomp-R-more)
- (define-key m "k" 'colorcomp-G-less)
- (define-key m "l" 'colorcomp-G-more)
- (define-key m "," 'colorcomp-B-less)
- (define-key m "." 'colorcomp-B-more)
- (define-key m " " 'colorcomp-copy-as-kill-and-exit)
- m))
address@hidden smallexample
-
-Note that we never modify the data in each node, which is fixed when the
-ewoc is created to be either @code{nil} or an index into the vector
address@hidden, the actual color components.
-
address@hidden Blinking
address@hidden Blinking Parentheses
address@hidden parenthesis matching
address@hidden blinking parentheses
address@hidden balancing parentheses
-
- This section describes the mechanism by which Emacs shows a matching
-open parenthesis when the user inserts a close parenthesis.
-
address@hidden blink-paren-function
-The value of this variable should be a function (of no arguments) to
-be called whenever a character with close parenthesis syntax is inserted.
-The value of @code{blink-paren-function} may be @code{nil}, in which
-case nothing is done.
address@hidden defvar
-
address@hidden blink-matching-paren
-If this variable is @code{nil}, then @code{blink-matching-open} does
-nothing.
address@hidden defopt
-
address@hidden blink-matching-paren-distance
-This variable specifies the maximum distance to scan for a matching
-parenthesis before giving up.
address@hidden defopt
-
address@hidden blink-matching-delay
-This variable specifies the number of seconds for the cursor to remain
-at the matching parenthesis. A fraction of a second often gives
-good results, but the default is 1, which works on all systems.
address@hidden defopt
-
address@hidden Command blink-matching-open
-This function is the default value of @code{blink-paren-function}. It
-assumes that point follows a character with close parenthesis syntax and
-moves the cursor momentarily to the matching opening character. If that
-character is not already on the screen, it displays the character's
-context in the echo area. To avoid long delays, this function does not
-search farther than @code{blink-matching-paren-distance} characters.
-
-Here is an example of calling this function explicitly.
-
address@hidden
address@hidden
-(defun interactive-blink-matching-open ()
address@hidden Do not break this line! -- rms.
address@hidden The first line of a doc string
address@hidden must stand alone.
- "Indicate momentarily the start of sexp before point."
- (interactive)
address@hidden group
address@hidden
- (let ((blink-matching-paren-distance
- (buffer-size))
- (blink-matching-paren t))
- (blink-matching-open)))
address@hidden group
address@hidden smallexample
address@hidden deffn
-
address@hidden Usual Display
address@hidden Usual Display Conventions
-
- The usual display conventions define how to display each character
-code. You can override these conventions by setting up a display table
-(@pxref{Display Tables}). Here are the usual display conventions:
-
address@hidden @bullet
address@hidden
-Character codes 32 through 126 map to glyph codes 32 through 126.
-Normally this means they display as themselves.
-
address@hidden
-Character code 9 is a horizontal tab. It displays as whitespace
-up to a position determined by @code{tab-width}.
-
address@hidden
-Character code 10 is a newline.
-
address@hidden
-All other codes in the range 0 through 31, and code 127, display in one
-of two ways according to the value of @code{ctl-arrow}. If it is
address@hidden, these codes map to sequences of two glyphs, where the
-first glyph is the @acronym{ASCII} code for @samp{^}. (A display table can
-specify a glyph to use instead of @samp{^}.) Otherwise, these codes map
-just like the codes in the range 128 to 255.
-
-On MS-DOS terminals, Emacs arranges by default for the character code
-127 to be mapped to the glyph code 127, which normally displays as an
-empty polygon. This glyph is used to display address@hidden characters
-that the MS-DOS terminal doesn't support. @xref{MS-DOS and MULE,,,
-emacs, The GNU Emacs Manual}.
-
address@hidden
-Character codes 128 through 255 map to sequences of four glyphs, where
-the first glyph is the @acronym{ASCII} code for @samp{\}, and the others are
-digit characters representing the character code in octal. (A display
-table can specify a glyph to use instead of @samp{\}.)
-
address@hidden
-Multibyte character codes above 256 are displayed as themselves, or as a
-question mark or empty box if the terminal cannot display that
-character.
address@hidden itemize
-
- The usual display conventions apply even when there is a display
-table, for any character whose entry in the active display table is
address@hidden Thus, when you set up a display table, you need only
-specify the characters for which you want special behavior.
-
- These display rules apply to carriage return (character code 13), when
-it appears in the buffer. But that character may not appear in the
-buffer where you expect it, if it was eliminated as part of end-of-line
-conversion (@pxref{Coding System Basics}).
-
- These variables affect the way certain characters are displayed on the
-screen. Since they change the number of columns the characters occupy,
-they also affect the indentation functions. These variables also affect
-how the mode line is displayed; if you want to force redisplay of the
-mode line using the new values, call the function
address@hidden (@pxref{Mode Line Format}).
-
address@hidden ctl-arrow
address@hidden control characters in display
-This buffer-local variable controls how control characters are
-displayed. If it is address@hidden, they are displayed as a caret
-followed by the character: @samp{^A}. If it is @code{nil}, they are
-displayed as a backslash followed by three octal digits: @samp{\001}.
address@hidden defopt
-
address@hidden Following may have overfull hbox.
address@hidden default-ctl-arrow
-The value of this variable is the default value for @code{ctl-arrow} in
-buffers that do not override it. @xref{Default Value}.
address@hidden defvar
-
address@hidden tab-width
-The value of this buffer-local variable is the spacing between tab
-stops used for displaying tab characters in Emacs buffers. The value
-is in units of columns, and the default is 8. Note that this feature
-is completely independent of the user-settable tab stops used by the
-command @code{tab-to-tab-stop}. @xref{Indent Tabs}.
address@hidden defopt
-
address@hidden Display Tables
address@hidden Display Tables
-
address@hidden display table
-You can use the @dfn{display table} feature to control how all possible
-character codes display on the screen. This is useful for displaying
-European languages that have letters not in the @acronym{ASCII} character
-set.
-
-The display table maps each character code into a sequence of
address@hidden, each glyph being a graphic that takes up one character
-position on the screen. You can also define how to display each glyph
-on your terminal, using the @dfn{glyph table}.
-
-Display tables affect how the mode line is displayed; if you want to
-force redisplay of the mode line using a new display table, call
address@hidden (@pxref{Mode Line Format}).
-
address@hidden
-* Display Table Format:: What a display table consists of.
-* Active Display Table:: How Emacs selects a display table to use.
-* Glyphs:: How to define a glyph, and what glyphs mean.
address@hidden menu
-
address@hidden Display Table Format
address@hidden Display Table Format
-
- A display table is actually a char-table (@pxref{Char-Tables}) with
address@hidden as its subtype.
-
address@hidden make-display-table
-This creates and returns a display table. The table initially has
address@hidden in all elements.
address@hidden defun
-
- The ordinary elements of the display table are indexed by character
-codes; the element at index @var{c} says how to display the character
-code @var{c}. The value should be @code{nil} or a vector of the
-glyphs to be output (@pxref{Glyphs}). @code{nil} says to display the
-character @var{c} according to the usual display conventions
-(@pxref{Usual Display}).
-
- @strong{Warning:} if you use the display table to change the display
-of newline characters, the whole buffer will be displayed as one long
-``line.''
-
- The display table also has six ``extra slots'' which serve special
-purposes. Here is a table of their meanings; @code{nil} in any slot
-means to use the default for that slot, as stated below.
-
address@hidden @asis
address@hidden 0
-The glyph for the end of a truncated screen line (the default for this
-is @samp{$}). @xref{Glyphs}. On graphical terminals, Emacs uses
-arrows in the fringes to indicate truncation, so the display table has
-no effect.
-
address@hidden 1
-The glyph for the end of a continued line (the default is @samp{\}).
-On graphical terminals, Emacs uses curved arrows in the fringes to
-indicate continuation, so the display table has no effect.
-
address@hidden 2
-The glyph for indicating a character displayed as an octal character
-code (the default is @samp{\}).
-
address@hidden 3
-The glyph for indicating a control character (the default is @samp{^}).
-
address@hidden 4
-A vector of glyphs for indicating the presence of invisible lines (the
-default is @samp{...}). @xref{Selective Display}.
-
address@hidden 5
-The glyph used to draw the border between side-by-side windows (the
-default is @samp{|}). @xref{Splitting Windows}. This takes effect only
-when there are no scroll bars; if scroll bars are supported and in use,
-a scroll bar separates the two windows.
address@hidden table
-
- For example, here is how to construct a display table that mimics the
-effect of setting @code{ctl-arrow} to a address@hidden value:
-
address@hidden
-(setq disptab (make-display-table))
-(let ((i 0))
- (while (< i 32)
- (or (= i ?\t) (= i ?\n)
- (aset disptab i (vector ?^ (+ i 64))))
- (setq i (1+ i)))
- (aset disptab 127 (vector ?^ ??)))
address@hidden example
-
address@hidden display-table-slot display-table slot
-This function returns the value of the extra slot @var{slot} of
address@hidden The argument @var{slot} may be a number from 0 to
-5 inclusive, or a slot name (symbol). Valid symbols are
address@hidden, @code{wrap}, @code{escape}, @code{control},
address@hidden, and @code{vertical-border}.
address@hidden defun
-
address@hidden set-display-table-slot display-table slot value
-This function stores @var{value} in the extra slot @var{slot} of
address@hidden The argument @var{slot} may be a number from 0 to
-5 inclusive, or a slot name (symbol). Valid symbols are
address@hidden, @code{wrap}, @code{escape}, @code{control},
address@hidden, and @code{vertical-border}.
address@hidden defun
-
address@hidden describe-display-table display-table
-This function displays a description of the display table
address@hidden in a help buffer.
address@hidden defun
-
address@hidden Command describe-current-display-table
-This command displays a description of the current display table in a
-help buffer.
address@hidden deffn
-
address@hidden Active Display Table
address@hidden Active Display Table
address@hidden active display table
-
- Each window can specify a display table, and so can each buffer. When
-a buffer @var{b} is displayed in window @var{w}, display uses the
-display table for window @var{w} if it has one; otherwise, the display
-table for buffer @var{b} if it has one; otherwise, the standard display
-table if any. The display table chosen is called the @dfn{active}
-display table.
-
address@hidden window-display-table &optional window
-This function returns @var{window}'s display table, or @code{nil}
-if @var{window} does not have an assigned display table. The default
-for @var{window} is the selected window.
address@hidden defun
-
address@hidden set-window-display-table window table
-This function sets the display table of @var{window} to @var{table}.
-The argument @var{table} should be either a display table or
address@hidden
address@hidden defun
-
address@hidden buffer-display-table
-This variable is automatically buffer-local in all buffers; its value in
-a particular buffer specifies the display table for that buffer. If it
-is @code{nil}, that means the buffer does not have an assigned display
-table.
address@hidden defvar
-
address@hidden standard-display-table
-This variable's value is the default display table, used whenever a
-window has no display table and neither does the buffer displayed in
-that window. This variable is @code{nil} by default.
address@hidden defvar
-
- If there is no display table to use for a particular window---that is,
-if the window specifies none, its buffer specifies none, and
address@hidden is @code{nil}---then Emacs uses the usual
-display conventions for all character codes in that window. @xref{Usual
-Display}.
-
-A number of functions for changing the standard display table
-are defined in the library @file{disp-table}.
-
address@hidden Glyphs
address@hidden Glyphs
-
address@hidden glyph
- A @dfn{glyph} is a generalization of a character; it stands for an
-image that takes up a single character position on the screen. Normally
-glyphs come from vectors in the display table (@pxref{Display Tables}).
-
- A glyph is represented in Lisp as a @dfn{glyph code}. A glyph code
-can be @dfn{simple} or it can be defined by the @dfn{glyph table}. A
-simple glyph code is just a way of specifying a character and a face
-to output it in. @xref{Faces}.
-
- The following functions are used to manipulate simple glyph codes:
-
address@hidden make-glyph-code char &optional face
-This function returns a simple glyph code representing char @var{char}
-with face @var{face}.
address@hidden defun
-
address@hidden glyph-char glyph
-This function returns the character of simple glyph code @var{glyph}.
address@hidden defun
-
address@hidden glyph-face glyph
-This function returns face of simple glyph code @var{glyph}, or
address@hidden if @var{glyph} has the default face (face-id 0).
address@hidden defun
-
- On character terminals, you can set up a @dfn{glyph table} to define
-the meaning of glyph codes (represented as small integers).
-
address@hidden glyph-table
-The value of this variable is the current glyph table. It should be
address@hidden or a vector whose @var{g}th element defines glyph code
address@hidden
-
-If a glyph code is greater than or equal to the length of the glyph
-table, that code is automatically simple. If @code{glyph-table} is
address@hidden then all glyph codes are simple.
-
-The glyph table is used only on character terminals. On graphical
-displays, all glyph codes are simple.
address@hidden defvar
-
- Here are the meaningful types of elements in the glyph table:
-
address@hidden @asis
address@hidden @var{string}
-Send the characters in @var{string} to the terminal to output
-this glyph code.
-
address@hidden @var{code}
-Define this glyph code as an alias for glyph code @var{code} created
-by @code{make-glyph-code}. You can use such an alias to define a
-small-numbered glyph code which specifies a character with a face.
-
address@hidden @code{nil}
-This glyph code is simple.
address@hidden table
-
address@hidden create-glyph string
-This function returns a newly-allocated glyph code which is set up to
-display by sending @var{string} to the terminal.
address@hidden defun
-
address@hidden Beeping
address@hidden Beeping
address@hidden @cindex beeping "beep" is adjacent
address@hidden bell
-
- This section describes how to make Emacs ring the bell (or blink the
-screen) to attract the user's attention. Be conservative about how
-often you do this; frequent bells can become irritating. Also be
-careful not to use just beeping when signaling an error is more
-appropriate. (@xref{Errors}.)
-
address@hidden ding &optional do-not-terminate
address@hidden keyboard macro termination
-This function beeps, or flashes the screen (see @code{visible-bell} below).
-It also terminates any keyboard macro currently executing unless
address@hidden is address@hidden
address@hidden defun
-
address@hidden beep &optional do-not-terminate
-This is a synonym for @code{ding}.
address@hidden defun
-
address@hidden visible-bell
-This variable determines whether Emacs should flash the screen to
-represent a bell. address@hidden means yes, @code{nil} means no. This
-is effective on graphical displays, and on text-only terminals
-provided the terminal's Termcap entry defines the visible bell
-capability (@samp{vb}).
address@hidden defopt
-
address@hidden ring-bell-function
-If this is address@hidden, it specifies how Emacs should ``ring the
-bell.'' Its value should be a function of no arguments. If this is
address@hidden, it takes precedence over the @code{visible-bell}
-variable.
address@hidden defvar
-
address@hidden Window Systems
address@hidden Window Systems
-
- Emacs works with several window systems, most notably the X Window
-System. Both Emacs and X use the term ``window,'' but use it
-differently. An Emacs frame is a single window as far as X is
-concerned; the individual Emacs windows are not known to X at all.
-
address@hidden window-system
-This variable tells Lisp programs what window system Emacs is running
-under. The possible values are
-
address@hidden @code
address@hidden x
address@hidden X Window System
-Emacs is displaying using X.
address@hidden pc
-Emacs is displaying using MS-DOS.
address@hidden w32
-Emacs is displaying using Windows.
address@hidden mac
-Emacs is displaying using a Macintosh.
address@hidden nil
-Emacs is using a character-based terminal.
address@hidden table
address@hidden defvar
-
address@hidden window-setup-hook
-This variable is a normal hook which Emacs runs after handling the
-initialization files. Emacs runs this hook after it has completed
-loading your init file, the default initialization file (if
-any), and the terminal-specific Lisp code, and running the hook
address@hidden
-
-This hook is used for internal purposes: setting up communication with
-the window system, and creating the initial window. Users should not
-interfere with it.
address@hidden defvar
-
address@hidden
- arch-tag: ffdf5714-7ecf-415b-9023-fbc6b409c2c6
address@hidden ignore
- [Emacs-diffs] Changes to display.texi,
Glenn Morris <=