1994-03-30 18:36:47 +00:00
|
|
|
@c -*-texinfo-*-
|
|
|
|
@c This is part of the GNU Emacs Lisp Reference Manual.
|
2002-06-11 01:50:36 +00:00
|
|
|
@c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1998, 1999, 2000, 2001, 2002
|
2000-01-05 14:59:32 +00:00
|
|
|
@c Free Software Foundation, Inc.
|
1994-03-30 18:36:47 +00:00
|
|
|
@c See the file elisp.texi for copying conditions.
|
|
|
|
@setfilename ../info/display
|
1998-04-20 17:43:57 +00:00
|
|
|
@node Display, Calendar, Processes, Top
|
1994-03-30 18:36:47 +00:00
|
|
|
@chapter Emacs Display
|
|
|
|
|
|
|
|
This chapter describes a number of features related to the display
|
|
|
|
that Emacs presents to the user.
|
|
|
|
|
|
|
|
@menu
|
|
|
|
* Refresh Screen:: Clearing the screen and redrawing everything on it.
|
1999-09-17 06:59:04 +00:00
|
|
|
* Forcing Redisplay:: Forcing redisplay.
|
1994-03-30 18:36:47 +00:00
|
|
|
* Truncation:: Folding or wrapping long text lines.
|
|
|
|
* The Echo Area:: Where messages are displayed.
|
1995-06-05 12:23:13 +00:00
|
|
|
* Invisible Text:: Hiding part of the buffer text.
|
|
|
|
* Selective Display:: Hiding part of the buffer text (the old way).
|
1994-03-30 18:36:47 +00:00
|
|
|
* Overlay Arrow:: Display of an arrow to indicate position.
|
|
|
|
* Temporary Displays:: Displays that go away automatically.
|
|
|
|
* Overlays:: Use overlays to highlight parts of the buffer.
|
1999-10-05 23:26:05 +00:00
|
|
|
* Width:: How wide a character or string is on the screen.
|
|
|
|
* Faces:: A face defines a graphics style for text characters:
|
|
|
|
font, colors, etc.
|
1999-09-17 06:59:04 +00:00
|
|
|
* Display Property:: Enabling special display features.
|
|
|
|
* Images:: Displaying images in Emacs buffers.
|
1994-03-30 18:36:47 +00:00
|
|
|
* Blinking:: How Emacs shows the matching open parenthesis.
|
|
|
|
* Inverse Video:: Specifying how the screen looks.
|
|
|
|
* 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.
|
|
|
|
@end menu
|
|
|
|
|
|
|
|
@node Refresh Screen
|
|
|
|
@section Refreshing the Screen
|
|
|
|
|
|
|
|
The function @code{redraw-frame} redisplays the entire contents of a
|
1998-05-26 18:56:56 +00:00
|
|
|
given frame (@pxref{Frames}).
|
1994-03-30 18:36:47 +00:00
|
|
|
|
|
|
|
@c Emacs 19 feature
|
|
|
|
@defun redraw-frame frame
|
|
|
|
This function clears and redisplays frame @var{frame}.
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
Even more powerful is @code{redraw-display}:
|
|
|
|
|
|
|
|
@deffn Command redraw-display
|
|
|
|
This function clears and redisplays all visible frames.
|
|
|
|
@end deffn
|
|
|
|
|
1995-06-06 19:21:15 +00:00
|
|
|
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.
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
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
|
1994-09-22 22:00:06 +00:00
|
|
|
resumption.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
|
|
|
@defvar no-redraw-on-reenter
|
|
|
|
@cindex suspend (cf. @code{no-redraw-on-reenter})
|
|
|
|
@cindex resume (cf. @code{no-redraw-on-reenter})
|
|
|
|
This variable controls whether Emacs redraws the entire screen after it
|
1998-02-28 01:53:53 +00:00
|
|
|
has been suspended and resumed. Non-@code{nil} means there is no need
|
1998-04-20 17:43:57 +00:00
|
|
|
to redraw, @code{nil} means redrawing is needed. The default is @code{nil}.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end defvar
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@node Forcing Redisplay
|
|
|
|
@section Forcing Redisplay
|
|
|
|
@cindex 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 non-@code{nil} value.
|
|
|
|
|
|
|
|
@tindex redisplay-dont-pause
|
|
|
|
@defvar redisplay-dont-pause
|
|
|
|
If this variable is non-@code{nil}, pending input does not
|
|
|
|
prevent or halt redisplay; redisplay occurs, and finishes,
|
|
|
|
regardless of whether input is available. This feature is available
|
|
|
|
as of Emacs 21.
|
|
|
|
@end defvar
|
|
|
|
|
|
|
|
You can request a display update, but only if no input is pending,
|
|
|
|
with @code{(sit-for 0)}. To force a display update even when input is
|
|
|
|
pending, do this:
|
|
|
|
|
|
|
|
@example
|
|
|
|
(let ((redisplay-dont-pause t))
|
|
|
|
(sit-for 0))
|
|
|
|
@end example
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@node Truncation
|
|
|
|
@section Truncation
|
|
|
|
@cindex line wrapping
|
|
|
|
@cindex continuation lines
|
|
|
|
@cindex @samp{$} in display
|
|
|
|
@cindex @samp{\} in display
|
|
|
|
|
|
|
|
When a line of text extends beyond the right edge of a window, the
|
|
|
|
line can either be continued on the next screen line, or truncated to
|
|
|
|
one screen line. The additional screen lines used to display a long
|
|
|
|
text line are called @dfn{continuation} lines. Normally, a @samp{$} in
|
|
|
|
the rightmost column of the window indicates truncation; a @samp{\} on
|
1998-04-20 17:43:57 +00:00
|
|
|
the rightmost column indicates a line that ``wraps'' onto the next line,
|
|
|
|
which is also called @dfn{continuing} the line. (The display table can
|
|
|
|
specify alternative indicators; see @ref{Display Tables}.)
|
1994-03-30 18:36:47 +00:00
|
|
|
|
2002-01-22 11:39:38 +00:00
|
|
|
@cindex fringes, and line continuation/truncation indicators
|
|
|
|
On a windowed display, the @samp{$} and @samp{\} indicators are
|
|
|
|
replaced with graphics bitmaps displayed on the thin areas right near
|
|
|
|
the window edges, called the @dfn{fringes}.
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
Note that continuation is different from 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}.
|
|
|
|
|
|
|
|
@defopt 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 non-@code{nil}, then these
|
|
|
|
lines are truncated.
|
|
|
|
|
|
|
|
If the variable @code{truncate-partial-width-windows} is non-@code{nil},
|
|
|
|
then truncation is always used for side-by-side windows (within one
|
|
|
|
frame) regardless of the value of @code{truncate-lines}.
|
|
|
|
@end defopt
|
|
|
|
|
1995-06-06 19:21:15 +00:00
|
|
|
@defopt default-truncate-lines
|
1994-03-30 18:36:47 +00:00
|
|
|
This variable is the default value for @code{truncate-lines}, for
|
1998-04-20 17:43:57 +00:00
|
|
|
buffers that do not have buffer-local values for it.
|
1995-06-06 19:21:15 +00:00
|
|
|
@end defopt
|
1994-03-30 18:36:47 +00:00
|
|
|
|
|
|
|
@defopt 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 non-@code{nil}, these lines are truncated; otherwise,
|
|
|
|
@code{truncate-lines} says what to do with them.
|
|
|
|
@end defopt
|
|
|
|
|
1998-05-19 03:45:57 +00:00
|
|
|
When horizontal scrolling (@pxref{Horizontal Scrolling}) is in use in
|
|
|
|
a window, that forces truncation.
|
|
|
|
|
1998-02-28 01:53:53 +00:00
|
|
|
You can override the glyphs that indicate continuation or truncation
|
|
|
|
using the display table; see @ref{Display Tables}.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1998-05-26 18:56:56 +00:00
|
|
|
If your buffer contains @emph{very} long lines, and you use
|
1995-06-05 12:23:13 +00:00
|
|
|
continuation to display them, just thinking about them can make Emacs
|
1995-06-06 19:21:15 +00:00
|
|
|
redisplay slow. The column computation and indentation functions also
|
|
|
|
become slow. Then you might find it advisable to set
|
|
|
|
@code{cache-long-line-scans} to @code{t}.
|
1995-06-05 12:23:13 +00:00
|
|
|
|
|
|
|
@defvar cache-long-line-scans
|
|
|
|
If this variable is non-@code{nil}, various indentation and motion
|
1995-06-06 19:21:15 +00:00
|
|
|
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.
|
1995-06-05 12:23:13 +00:00
|
|
|
|
1995-06-06 19:21:15 +00:00
|
|
|
Turning on the cache slows down processing of short lines somewhat.
|
1995-06-05 12:23:13 +00:00
|
|
|
|
1998-04-20 17:43:57 +00:00
|
|
|
This variable is automatically buffer-local in every buffer.
|
1995-06-05 12:23:13 +00:00
|
|
|
@end defvar
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@node The Echo Area
|
|
|
|
@section The Echo Area
|
|
|
|
@cindex error display
|
|
|
|
@cindex echo area
|
|
|
|
|
1995-06-05 12:23:13 +00:00
|
|
|
The @dfn{echo area} is used for displaying messages made with the
|
1994-03-30 18:36:47 +00:00
|
|
|
@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}).
|
|
|
|
Error messages appear in the echo area; see @ref{Errors}.
|
|
|
|
|
|
|
|
You can write output in the echo area by using the Lisp printing
|
|
|
|
functions with @code{t} as the stream (@pxref{Output Functions}), or as
|
|
|
|
follows:
|
|
|
|
|
|
|
|
@defun message string &rest arguments
|
2001-09-08 17:49:11 +00:00
|
|
|
This function displays a message in the echo area. The
|
1994-03-30 18:36:47 +00:00
|
|
|
argument @var{string} is similar to a C language @code{printf} control
|
|
|
|
string. See @code{format} in @ref{String Conversion}, for the details
|
|
|
|
on the conversion specifications. @code{message} returns the
|
|
|
|
constructed string.
|
|
|
|
|
1994-05-28 15:27:52 +00:00
|
|
|
In batch mode, @code{message} prints the message text on the standard
|
|
|
|
error stream, followed by a newline.
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
If @var{string}, or strings among the @var{arguments}, have @code{face}
|
|
|
|
text properties, these affect the way the message is displayed.
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@c Emacs 19 feature
|
1999-09-17 06:59:04 +00:00
|
|
|
If @var{string} is @code{nil}, @code{message} 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.
|
1994-05-28 15:27:52 +00:00
|
|
|
|
2001-09-08 17:49:11 +00:00
|
|
|
@vindex message-truncate-lines
|
2001-09-10 05:34:15 +00:00
|
|
|
Normally, displaying a long message resizes the echo area to display
|
|
|
|
the entire message. But if the variable @code{message-truncate-lines}
|
|
|
|
is non-@code{nil}, the echo area does not resize, and the message is
|
|
|
|
truncated to fit it, as in Emacs 20 and before.
|
2001-09-08 17:49:11 +00:00
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@example
|
|
|
|
@group
|
|
|
|
(message "Minibuffer depth is %d."
|
|
|
|
(minibuffer-depth))
|
|
|
|
@print{} Minibuffer depth is 0.
|
|
|
|
@result{} "Minibuffer depth is 0."
|
|
|
|
@end group
|
|
|
|
|
|
|
|
@group
|
|
|
|
---------- Echo Area ----------
|
|
|
|
Minibuffer depth is 0.
|
|
|
|
---------- Echo Area ----------
|
|
|
|
@end group
|
|
|
|
@end example
|
2000-10-08 01:41:04 +00:00
|
|
|
|
|
|
|
To automatically display a message in the echo area or in a pop-buffer,
|
|
|
|
depending on its size, use @code{display-message-or-buffer}.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end defun
|
|
|
|
|
1999-07-17 02:15:13 +00:00
|
|
|
@tindex with-temp-message
|
|
|
|
@defmac 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
|
|
|
|
@var{body}, then returns the value of the last body form while restoring
|
|
|
|
the previous echo area contents.
|
|
|
|
@end defmac
|
|
|
|
|
1998-07-29 03:01:39 +00:00
|
|
|
@defun message-or-box 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
|
|
|
|
@code{last-nonmenu-event} (@pxref{Command Loop Info}) is either
|
|
|
|
@code{nil} 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
|
|
|
|
@ref{Yes-or-No Queries}.)
|
|
|
|
|
|
|
|
You can force use of the mouse or of the echo area by binding
|
|
|
|
@code{last-nonmenu-event} to a suitable value around the call.
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
@defun message-box string &rest arguments
|
|
|
|
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
|
|
|
|
@code{message}.
|
|
|
|
@end defun
|
|
|
|
|
2000-10-08 01:41:04 +00:00
|
|
|
@defun display-message-or-buffer message &optional buffer-name not-this-window frame
|
2000-10-24 23:17:02 +00:00
|
|
|
@tindex display-message-or-buffer
|
2000-10-08 01:41:04 +00:00
|
|
|
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,
|
|
|
|
@code{display-buffer} 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
|
|
|
|
@var{buffer-name} 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
|
|
|
|
@code{display-buffer}, and only used if a buffer is displayed.
|
|
|
|
@end defun
|
|
|
|
|
1998-02-28 01:53:53 +00:00
|
|
|
@defun current-message
|
|
|
|
This function returns the message currently being displayed in the
|
|
|
|
echo area, or @code{nil} if there is none.
|
|
|
|
@end defun
|
|
|
|
|
1998-04-20 17:43:57 +00:00
|
|
|
@defvar cursor-in-echo-area
|
|
|
|
This variable controls where the cursor appears when a message is
|
|
|
|
displayed in the echo area. If it is non-@code{nil}, 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.
|
|
|
|
@end defvar
|
|
|
|
|
1998-02-28 01:53:53 +00:00
|
|
|
@defvar echo-area-clear-hook
|
|
|
|
This normal hook is run whenever the echo area is cleared---either by
|
|
|
|
@code{(message nil)} or for any other reason.
|
|
|
|
@end defvar
|
|
|
|
|
1995-06-05 12:23:13 +00:00
|
|
|
Almost all the messages displayed in the echo area are also recorded
|
|
|
|
in the @samp{*Messages*} buffer.
|
|
|
|
|
|
|
|
@defopt 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:
|
|
|
|
|
|
|
|
@example
|
|
|
|
(let (message-log-max)
|
|
|
|
(message @dots{}))
|
|
|
|
@end example
|
|
|
|
@end defopt
|
|
|
|
|
1995-06-06 19:21:15 +00:00
|
|
|
@defvar echo-keystrokes
|
|
|
|
This variable determines how much time should elapse before command
|
2000-03-02 22:08:36 +00:00
|
|
|
characters echo. Its value must be an integer or floating point number,
|
|
|
|
which specifies the
|
1995-06-06 19:21:15 +00:00
|
|
|
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
|
1998-05-19 03:45:57 +00:00
|
|
|
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.)
|
1995-06-06 19:21:15 +00:00
|
|
|
|
|
|
|
If the value is zero, then command input is not echoed.
|
|
|
|
@end defvar
|
|
|
|
|
1995-06-05 12:23:13 +00:00
|
|
|
@node Invisible Text
|
|
|
|
@section Invisible Text
|
|
|
|
|
|
|
|
@cindex 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
|
1998-05-19 03:45:57 +00:00
|
|
|
text property (@pxref{Text Properties}) or a property of an overlay
|
|
|
|
(@pxref{Overlays}).
|
1995-06-05 12:23:13 +00:00
|
|
|
|
|
|
|
In the simplest case, any non-@code{nil} @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
|
1998-04-20 17:43:57 +00:00
|
|
|
@code{invisible} property works.
|
1995-06-05 12:23:13 +00:00
|
|
|
|
|
|
|
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
|
1999-10-05 23:26:05 +00:00
|
|
|
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.
|
1995-06-05 12:23:13 +00:00
|
|
|
|
|
|
|
@defvar buffer-invisibility-spec
|
|
|
|
This variable specifies which kinds of @code{invisible} properties
|
|
|
|
actually make a character invisible.
|
|
|
|
|
|
|
|
@table @asis
|
|
|
|
@item @code{t}
|
|
|
|
A character is invisible if its @code{invisible} property is
|
|
|
|
non-@code{nil}. This is the default.
|
|
|
|
|
|
|
|
@item a list
|
1998-04-20 17:43:57 +00:00
|
|
|
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:
|
1995-06-05 12:23:13 +00:00
|
|
|
|
|
|
|
@table @code
|
|
|
|
@item @var{atom}
|
1998-04-20 17:43:57 +00:00
|
|
|
A character is invisible if its @code{invisible} property value
|
1995-06-05 12:23:13 +00:00
|
|
|
is @var{atom} or if it is a list with @var{atom} as a member.
|
|
|
|
|
|
|
|
@item (@var{atom} . t)
|
1998-04-20 17:43:57 +00:00
|
|
|
A character is invisible if its @code{invisible} property value
|
1995-06-05 12:23:13 +00:00
|
|
|
is @var{atom} or if it is a list with @var{atom} as a member.
|
|
|
|
Moreover, if this character is at the end of a line and is followed
|
|
|
|
by a visible newline, it displays an ellipsis.
|
|
|
|
@end table
|
|
|
|
@end table
|
|
|
|
@end defvar
|
|
|
|
|
1998-02-28 01:53:53 +00:00
|
|
|
Two functions are specifically provided for adding elements to
|
|
|
|
@code{buffer-invisibility-spec} and removing elements from it.
|
|
|
|
|
|
|
|
@defun add-to-invisibility-spec element
|
|
|
|
Add the element @var{element} to @code{buffer-invisibility-spec}
|
|
|
|
(if it is not already present in that list).
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
@defun remove-from-invisibility-spec element
|
|
|
|
Remove the element @var{element} from @code{buffer-invisibility-spec}.
|
1999-10-05 23:26:05 +00:00
|
|
|
This does nothing if @var{element} is not in the list.
|
1998-02-28 01:53:53 +00:00
|
|
|
@end defun
|
|
|
|
|
|
|
|
One convention about the use of @code{buffer-invisibility-spec} is
|
|
|
|
that a major mode should use the mode's own name as an element of
|
|
|
|
@code{buffer-invisibility-spec} and as the value of the @code{invisible}
|
|
|
|
property:
|
|
|
|
|
|
|
|
@example
|
1998-04-20 17:43:57 +00:00
|
|
|
;; @r{If you want to display an ellipsis:}
|
1998-02-28 01:53:53 +00:00
|
|
|
(add-to-invisibility-spec '(my-symbol . t))
|
1998-04-20 17:43:57 +00:00
|
|
|
;; @r{If you don't want ellipsis:}
|
1998-02-28 01:53:53 +00:00
|
|
|
(add-to-invisibility-spec 'my-symbol)
|
|
|
|
|
|
|
|
(overlay-put (make-overlay beginning end)
|
|
|
|
'invisible 'my-symbol)
|
|
|
|
|
1998-04-20 17:43:57 +00:00
|
|
|
;; @r{When done with the overlays:}
|
1998-02-28 01:53:53 +00:00
|
|
|
(remove-from-invisibility-spec '(my-symbol . t))
|
1998-04-20 17:43:57 +00:00
|
|
|
;; @r{Or respectively:}
|
1998-02-28 01:53:53 +00:00
|
|
|
(remove-from-invisibility-spec 'my-symbol)
|
|
|
|
@end example
|
|
|
|
|
1996-07-23 15:37:09 +00:00
|
|
|
@vindex line-move-ignore-invisible
|
1995-06-06 19:21:15 +00:00
|
|
|
Ordinarily, commands that operate on text or move point do not care
|
1996-07-23 15:37:09 +00:00
|
|
|
whether the text is invisible. The user-level line motion commands
|
|
|
|
explicitly ignore invisible newlines if
|
|
|
|
@code{line-move-ignore-invisible} is non-@code{nil}, but only because
|
|
|
|
they are explicitly programmed to do so.
|
1995-06-06 19:21:15 +00:00
|
|
|
|
1998-02-28 01:53:53 +00:00
|
|
|
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 non-@code{nil}
|
|
|
|
@code{isearch-open-invisible} 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
|
1998-05-27 23:47:15 +00:00
|
|
|
want this to be done differently for a certain overlay, give it an
|
1998-02-28 01:53:53 +00:00
|
|
|
@code{isearch-open-invisible-temporary} property which is a function.
|
|
|
|
The function is called with two arguments: the first is the overlay, and
|
1999-12-25 13:01:06 +00:00
|
|
|
the second is @code{nil} to make the overlay visible, or @code{t} to
|
1998-05-19 03:45:57 +00:00
|
|
|
make it invisible again.
|
1998-02-28 01:53:53 +00:00
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@node Selective Display
|
|
|
|
@section Selective Display
|
|
|
|
@cindex selective display
|
|
|
|
|
1998-04-20 17:43:57 +00:00
|
|
|
@dfn{Selective display} refers to a pair of related features for
|
|
|
|
hiding certain lines on the screen.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
|
|
|
The first variant, explicit selective display, is designed for use in
|
1998-04-20 17:43:57 +00:00
|
|
|
a Lisp program: it controls which lines are hidden by altering the text.
|
|
|
|
The invisible text feature (@pxref{Invisible Text}) has partially
|
|
|
|
replaced this feature.
|
1995-06-05 12:23:13 +00:00
|
|
|
|
|
|
|
In the second variant, the choice of lines to hide is made
|
1995-06-06 19:21:15 +00:00
|
|
|
automatically based on indentation. This variant is designed to be a
|
1995-06-05 12:23:13 +00:00
|
|
|
user-level feature.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
|
|
|
The way you control explicit selective display is by replacing a
|
1994-09-22 22:00:06 +00:00
|
|
|
newline (control-j) with a carriage return (control-m). The text that
|
1994-03-30 18:36:47 +00:00
|
|
|
was formerly a line following that newline is now invisible. 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
|
|
|
|
invisible text. However, the replacement of newline characters with
|
|
|
|
carriage return characters affects some editing commands. For example,
|
|
|
|
@code{next-line} skips invisible lines, since it searches only for
|
|
|
|
newlines. Modes that use selective display can also define commands
|
|
|
|
that take account of the newlines, or that make parts of the text
|
|
|
|
visible or invisible.
|
|
|
|
|
|
|
|
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 invisible. The selective display
|
|
|
|
effect is seen only within Emacs.
|
|
|
|
|
|
|
|
@defvar selective-display
|
|
|
|
This buffer-local variable enables selective display. This means that
|
|
|
|
lines, or portions of lines, may be made invisible.
|
|
|
|
|
|
|
|
@itemize @bullet
|
|
|
|
@item
|
1999-10-05 23:26:05 +00:00
|
|
|
If the value of @code{selective-display} is @code{t}, then the character
|
|
|
|
control-m marks the start of invisible text; the control-m, and the rest
|
|
|
|
of the line following it, are not displayed. This is explicit selective
|
|
|
|
display.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
|
|
|
@item
|
|
|
|
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.
|
|
|
|
@end itemize
|
|
|
|
|
|
|
|
When some portion of a buffer is invisible, the vertical movement
|
|
|
|
commands operate as if that portion did not exist, allowing a single
|
|
|
|
@code{next-line} command to skip any number of invisible lines.
|
|
|
|
However, character movement commands (such as @code{forward-char}) do
|
|
|
|
not skip the invisible portion, and it is possible (if tricky) to insert
|
|
|
|
or delete text in an invisible portion.
|
|
|
|
|
|
|
|
In the examples below, we show the @emph{display appearance} of the
|
|
|
|
buffer @code{foo}, which changes with the value of
|
|
|
|
@code{selective-display}. The @emph{contents} of the buffer do not
|
|
|
|
change.
|
|
|
|
|
|
|
|
@example
|
|
|
|
@group
|
|
|
|
(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 ----------
|
|
|
|
@end group
|
|
|
|
|
|
|
|
@group
|
|
|
|
(setq selective-display 2)
|
|
|
|
@result{} 2
|
|
|
|
|
|
|
|
---------- Buffer: foo ----------
|
|
|
|
1 on this column
|
|
|
|
2on this column
|
|
|
|
2on this column
|
|
|
|
1 on this column
|
|
|
|
---------- Buffer: foo ----------
|
|
|
|
@end group
|
|
|
|
@end example
|
|
|
|
@end defvar
|
|
|
|
|
|
|
|
@defvar selective-display-ellipses
|
|
|
|
If this buffer-local variable is non-@code{nil}, then Emacs displays
|
|
|
|
@samp{@dots{}} at the end of a line that is followed by invisible text.
|
|
|
|
This example is a continuation of the previous one.
|
|
|
|
|
|
|
|
@example
|
|
|
|
@group
|
|
|
|
(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 ----------
|
|
|
|
@end group
|
|
|
|
@end example
|
|
|
|
|
|
|
|
You can use a display table to substitute other text for the ellipsis
|
|
|
|
(@samp{@dots{}}). @xref{Display Tables}.
|
|
|
|
@end defvar
|
|
|
|
|
|
|
|
@node Overlay Arrow
|
|
|
|
@section The Overlay Arrow
|
|
|
|
@cindex overlay arrow
|
|
|
|
|
|
|
|
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.
|
|
|
|
|
|
|
|
@defvar overlay-arrow-string
|
2002-01-22 11:39:38 +00:00
|
|
|
@cindex fringe, and overlay arrow display
|
1994-09-22 22:00:06 +00:00
|
|
|
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.
|
2000-06-06 14:56:30 +00:00
|
|
|
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.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end defvar
|
|
|
|
|
|
|
|
@defvar overlay-arrow-position
|
1994-09-22 22:00:06 +00:00
|
|
|
This variable holds a marker that indicates where to display the overlay
|
2000-06-06 14:56:30 +00:00
|
|
|
arrow. It should point at the beginning of a line. On a non-graphical
|
|
|
|
display the arrow text
|
1994-09-22 22:00:06 +00:00
|
|
|
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 string is displayed only in the buffer that this marker
|
1994-03-30 18:36:47 +00:00
|
|
|
points into. Thus, only one buffer can have an overlay arrow at any
|
|
|
|
given time.
|
|
|
|
@c !!! overlay-arrow-position: but the overlay string may remain in the display
|
|
|
|
@c of some other buffer until an update is required. This should be fixed
|
|
|
|
@c now. Is it?
|
|
|
|
@end defvar
|
|
|
|
|
1998-04-20 17:43:57 +00:00
|
|
|
You can do a similar job by creating an overlay with a
|
1995-06-05 12:23:13 +00:00
|
|
|
@code{before-string} property. @xref{Overlay Properties}.
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@node Temporary Displays
|
|
|
|
@section Temporary Displays
|
|
|
|
|
1998-04-20 17:43:57 +00:00
|
|
|
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.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
|
|
|
@defspec with-output-to-temp-buffer buffer-name forms@dots{}
|
1999-07-17 02:15:13 +00:00
|
|
|
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
|
|
|
|
@code{with-output-to-temp-buffer} makes this buffer read-only at the
|
|
|
|
end, and also scans it for function and variable names to make them into
|
|
|
|
clickable cross-references.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
|
|
|
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.
|
|
|
|
|
|
|
|
@code{with-output-to-temp-buffer} 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).
|
|
|
|
@xref{Output Functions}.
|
|
|
|
|
1999-07-17 02:15:13 +00:00
|
|
|
Several hooks are available for customizing the behavior
|
|
|
|
of this construct; they are listed below.
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
The value of the last form in @var{forms} is returned.
|
|
|
|
|
|
|
|
@example
|
|
|
|
@group
|
|
|
|
---------- Buffer: foo ----------
|
|
|
|
This is the contents of foo.
|
|
|
|
---------- Buffer: foo ----------
|
|
|
|
@end group
|
|
|
|
|
|
|
|
@group
|
|
|
|
(with-output-to-temp-buffer "foo"
|
|
|
|
(print 20)
|
|
|
|
(print standard-output))
|
|
|
|
@result{} #<buffer foo>
|
|
|
|
|
|
|
|
---------- Buffer: foo ----------
|
|
|
|
20
|
|
|
|
|
|
|
|
#<buffer foo>
|
|
|
|
|
|
|
|
---------- Buffer: foo ----------
|
|
|
|
@end group
|
|
|
|
@end example
|
|
|
|
@end defspec
|
|
|
|
|
|
|
|
@defvar temp-buffer-show-function
|
1994-09-22 22:00:06 +00:00
|
|
|
If this variable is non-@code{nil}, @code{with-output-to-temp-buffer}
|
1994-03-30 18:36:47 +00:00
|
|
|
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.
|
1998-05-19 03:45:57 +00:00
|
|
|
|
|
|
|
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
|
1999-07-17 02:15:13 +00:00
|
|
|
@code{save-selected-window} and with the chosen window and buffer
|
1998-05-19 03:45:57 +00:00
|
|
|
selected.
|
|
|
|
@end defvar
|
|
|
|
|
1999-07-17 02:15:13 +00:00
|
|
|
@defvar temp-buffer-setup-hook
|
|
|
|
@tindex temp-buffer-setup-hook
|
|
|
|
This normal hook is run by @code{with-output-to-temp-buffer} before
|
2001-12-16 18:36:16 +00:00
|
|
|
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.
|
1999-07-17 02:15:13 +00:00
|
|
|
@end defvar
|
|
|
|
|
1998-05-19 03:45:57 +00:00
|
|
|
@defvar temp-buffer-show-hook
|
|
|
|
This normal hook is run by @code{with-output-to-temp-buffer} after
|
2001-12-16 18:36:16 +00:00
|
|
|
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.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end defvar
|
|
|
|
|
|
|
|
@defun momentary-string-display string position &optional char message
|
|
|
|
This function momentarily displays @var{string} in the current buffer at
|
|
|
|
@var{position}. 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
|
|
|
|
@var{char} is a space by default.
|
|
|
|
|
|
|
|
The return value of @code{momentary-string-display} is not meaningful.
|
|
|
|
|
1995-06-06 19:21:15 +00:00
|
|
|
If the string @var{string} does not contain control characters, you can
|
1998-04-20 17:43:57 +00:00
|
|
|
do the same job in a more general way by creating (and then subsequently
|
|
|
|
deleting) an overlay with a @code{before-string} property.
|
|
|
|
@xref{Overlay Properties}.
|
1995-06-06 19:21:15 +00:00
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
If @var{message} is non-@code{nil}, 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:
|
|
|
|
|
|
|
|
@example
|
|
|
|
@group
|
|
|
|
---------- Buffer: foo ----------
|
|
|
|
This is the contents of foo.
|
|
|
|
@point{}Second line.
|
|
|
|
---------- Buffer: foo ----------
|
|
|
|
@end group
|
|
|
|
|
|
|
|
@group
|
|
|
|
(momentary-string-display
|
|
|
|
"**** Important Message! ****"
|
|
|
|
(point) ?\r
|
|
|
|
"Type RET when done reading")
|
|
|
|
@result{} t
|
|
|
|
@end group
|
|
|
|
|
|
|
|
@group
|
|
|
|
---------- Buffer: foo ----------
|
|
|
|
This is the contents of foo.
|
|
|
|
**** Important Message! ****Second line.
|
|
|
|
---------- Buffer: foo ----------
|
|
|
|
|
|
|
|
---------- Echo Area ----------
|
|
|
|
Type RET when done reading
|
|
|
|
---------- Echo Area ----------
|
|
|
|
@end group
|
|
|
|
@end example
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
@node Overlays
|
|
|
|
@section Overlays
|
|
|
|
@cindex overlays
|
|
|
|
|
|
|
|
You can use @dfn{overlays} to alter the appearance of a buffer's text on
|
1995-06-06 19:21:15 +00:00
|
|
|
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.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
|
|
|
@menu
|
|
|
|
* Overlay Properties:: How to read and set properties.
|
|
|
|
What properties do to the screen display.
|
1999-12-03 19:38:44 +00:00
|
|
|
* Managing Overlays:: Creating and moving overlays.
|
|
|
|
* Finding Overlays:: Searching for overlays.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end menu
|
|
|
|
|
|
|
|
@node Overlay Properties
|
|
|
|
@subsection Overlay Properties
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
Overlay properties are like text properties in that the properties that
|
1998-05-19 03:45:57 +00:00
|
|
|
alter how a character is displayed can come from either source. But in
|
|
|
|
most respects they are different. Text properties are considered a part
|
|
|
|
of the text; overlays 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 changes are not recorded in the buffer's undo list.
|
|
|
|
@xref{Text Properties}, for comparison.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
These functions are used for reading and writing the properties of an
|
|
|
|
overlay:
|
|
|
|
|
|
|
|
@defun overlay-get overlay prop
|
|
|
|
This function returns the value of property @var{prop} recorded in
|
|
|
|
@var{overlay}, 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}.
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
@defun overlay-put overlay prop value
|
|
|
|
This function sets the value of property @var{prop} recorded in
|
|
|
|
@var{overlay} to @var{value}. It returns @var{value}.
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
See also the function @code{get-char-property} which checks both
|
|
|
|
overlay properties and text properties for a given character.
|
|
|
|
@xref{Examining Properties}.
|
|
|
|
|
|
|
|
Many overlay properties have special meanings; here is a table
|
|
|
|
of them:
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@table @code
|
|
|
|
@item priority
|
|
|
|
@kindex priority @r{(overlay property)}
|
|
|
|
This property's value (which should be a nonnegative number) determines
|
|
|
|
the priority of the overlay. The priority matters when two or more
|
|
|
|
overlays cover the same character and both specify a face for display;
|
|
|
|
the one whose @code{priority} value is larger takes priority over the
|
|
|
|
other, and its face attributes override the face attributes of the lower
|
|
|
|
priority overlay.
|
|
|
|
|
|
|
|
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.
|
|
|
|
|
|
|
|
@item window
|
|
|
|
@kindex window @r{(overlay property)}
|
|
|
|
If the @code{window} property is non-@code{nil}, then the overlay
|
|
|
|
applies only on that window.
|
|
|
|
|
1995-06-05 12:23:13 +00:00
|
|
|
@item category
|
|
|
|
@kindex category @r{(overlay property)}
|
|
|
|
If an overlay has a @code{category} property, we call it the
|
1995-06-06 19:21:15 +00:00
|
|
|
@dfn{category} of the overlay. It should be a symbol. The properties
|
1995-06-05 12:23:13 +00:00
|
|
|
of the symbol serve as defaults for the properties of the overlay.
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@item face
|
|
|
|
@kindex face @r{(overlay property)}
|
1998-02-28 01:53:53 +00:00
|
|
|
This property controls the way text is displayed---for example, which
|
1999-09-17 06:59:04 +00:00
|
|
|
font and which colors. @xref{Faces}, for more information.
|
1998-02-28 01:53:53 +00:00
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
In the simplest case, the value is a face name. It can also be a list;
|
1999-10-05 23:26:05 +00:00
|
|
|
then each element can be any of these possibilities:
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
@itemize @bullet
|
|
|
|
@item
|
|
|
|
A face name (a symbol or string).
|
|
|
|
|
|
|
|
@item
|
|
|
|
Starting in Emacs 21, a property list of face attributes. This has the
|
|
|
|
form (@var{keyword} @var{value} @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}.
|
|
|
|
|
|
|
|
@item
|
|
|
|
A cons cell of the form @code{(foreground-color . @var{color-name})} or
|
|
|
|
@code{(background-color . @var{color-name})}. These elements specify
|
|
|
|
just the foreground color or just the background color.
|
|
|
|
|
|
|
|
@code{(foreground-color . @var{color-name})} is equivalent to
|
|
|
|
@code{(:foreground @var{color-name})}, and likewise for the background.
|
|
|
|
@end itemize
|
1994-03-30 18:36:47 +00:00
|
|
|
|
|
|
|
@item mouse-face
|
|
|
|
@kindex mouse-face @r{(overlay property)}
|
|
|
|
This property is used instead of @code{face} when the mouse is within
|
1998-02-28 01:53:53 +00:00
|
|
|
the range of the overlay.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@item display
|
|
|
|
@kindex display @r{(overlay property)}
|
|
|
|
This property activates various features that change the
|
|
|
|
way text is displayed. For example, it can make text appear taller
|
2001-07-04 06:22:15 +00:00
|
|
|
or shorter, higher or lower, wider or narrower, or replaced with an image.
|
1999-09-17 06:59:04 +00:00
|
|
|
@xref{Display Property}.
|
|
|
|
|
|
|
|
@item help-echo
|
|
|
|
@kindex help-echo @r{(text property)}
|
2000-09-04 13:57:47 +00:00
|
|
|
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
|
2002-06-11 19:28:20 +00:00
|
|
|
help-echo}.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@item modification-hooks
|
|
|
|
@kindex 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
|
1995-06-05 12:23:13 +00:00
|
|
|
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
|
1994-04-24 21:47:17 +00:00
|
|
|
modified.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1995-06-05 12:23:13 +00:00
|
|
|
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
|
1995-06-06 19:21:15 +00:00
|
|
|
beginning and end are equal.)
|
1995-06-05 12:23:13 +00:00
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@item insert-in-front-hooks
|
|
|
|
@kindex insert-in-front-hooks @r{(overlay property)}
|
1995-06-05 12:23:13 +00:00
|
|
|
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.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
|
|
|
@item insert-behind-hooks
|
|
|
|
@kindex insert-behind-hooks @r{(overlay property)}
|
1995-06-05 12:23:13 +00:00
|
|
|
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.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
|
|
|
@item invisible
|
|
|
|
@kindex invisible @r{(overlay property)}
|
1995-06-05 12:23:13 +00:00
|
|
|
The @code{invisible} property can make the text in the overlay
|
|
|
|
invisible, which means that it does not appear on the screen.
|
|
|
|
@xref{Invisible Text}, for details.
|
|
|
|
|
|
|
|
@item intangible
|
|
|
|
@kindex intangible @r{(overlay property)}
|
|
|
|
The @code{intangible} property on an overlay works just like the
|
1995-06-06 19:21:15 +00:00
|
|
|
@code{intangible} text property. @xref{Special Properties}, for details.
|
1998-02-28 01:53:53 +00:00
|
|
|
|
|
|
|
@item isearch-open-invisible
|
1998-05-19 03:45:57 +00:00
|
|
|
This property tells incremental search how to make an invisible overlay
|
|
|
|
visible, permanently, if the final match overlaps it. @xref{Invisible
|
1998-02-28 01:53:53 +00:00
|
|
|
Text}.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1998-05-19 03:45:57 +00:00
|
|
|
@item isearch-open-invisible-temporary
|
|
|
|
This property tells incremental search how to make an invisible overlay
|
|
|
|
visible, temporarily, during the search. @xref{Invisible Text}.
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@item before-string
|
|
|
|
@kindex 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
|
1999-10-05 23:26:05 +00:00
|
|
|
sense---only on the screen.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
|
|
|
@item after-string
|
|
|
|
@kindex 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
|
1999-10-05 23:26:05 +00:00
|
|
|
sense---only on the screen.
|
1995-06-05 12:23:13 +00:00
|
|
|
|
|
|
|
@item evaporate
|
|
|
|
@kindex evaporate @r{(overlay property)}
|
|
|
|
If this property is non-@code{nil}, the overlay is deleted automatically
|
|
|
|
if it ever becomes empty (i.e., if it spans no characters).
|
1996-09-04 15:38:37 +00:00
|
|
|
|
2000-05-23 09:44:28 +00:00
|
|
|
@item local-map
|
1998-04-20 17:43:57 +00:00
|
|
|
@cindex keymap of character (and overlays)
|
2000-05-23 09:44:28 +00:00
|
|
|
@kindex local-map @r{(overlay property)}
|
1996-09-04 15:38:37 +00:00
|
|
|
If this property is non-@code{nil}, 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}.
|
2000-11-29 14:53:29 +00:00
|
|
|
|
|
|
|
@item keymap
|
|
|
|
@kindex 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.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end table
|
|
|
|
|
|
|
|
@node Managing Overlays
|
|
|
|
@subsection Managing Overlays
|
|
|
|
|
|
|
|
This section describes the functions to create, delete and move
|
|
|
|
overlays, and to examine their contents.
|
|
|
|
|
1998-02-28 01:53:53 +00:00
|
|
|
@defun make-overlay start end &optional buffer front-advance rear-advance
|
1994-09-22 22:00:06 +00:00
|
|
|
This function creates and returns an overlay that belongs to
|
1994-03-30 18:36:47 +00:00
|
|
|
@var{buffer} 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.
|
1998-02-28 01:53:53 +00:00
|
|
|
|
|
|
|
The arguments @var{front-advance} and @var{rear-advance} specify the
|
|
|
|
insertion type for the start of the overlay and for the end of the
|
1999-12-03 19:11:12 +00:00
|
|
|
overlay, respectively. @xref{Marker Insertion Types}.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end defun
|
|
|
|
|
|
|
|
@defun overlay-start overlay
|
1998-02-28 01:53:53 +00:00
|
|
|
This function returns the position at which @var{overlay} starts,
|
|
|
|
as an integer.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end defun
|
|
|
|
|
|
|
|
@defun overlay-end overlay
|
1998-02-28 01:53:53 +00:00
|
|
|
This function returns the position at which @var{overlay} ends,
|
|
|
|
as an integer.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end defun
|
|
|
|
|
|
|
|
@defun overlay-buffer overlay
|
|
|
|
This function returns the buffer that @var{overlay} belongs to.
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
@defun delete-overlay overlay
|
|
|
|
This function deletes @var{overlay}. The overlay continues to exist as
|
1999-12-03 19:11:12 +00:00
|
|
|
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.
|
1998-05-19 03:45:57 +00:00
|
|
|
|
1999-12-03 19:11:12 +00:00
|
|
|
A deleted overlay is not permanently disconnected. You can give it a
|
|
|
|
position in a buffer again by calling @code{move-overlay}.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end defun
|
|
|
|
|
|
|
|
@defun 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}
|
1999-12-03 19:11:12 +00:00
|
|
|
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.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
|
|
|
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''.
|
|
|
|
@end defun
|
|
|
|
|
1999-12-03 19:11:12 +00:00
|
|
|
Here are some examples:
|
|
|
|
|
|
|
|
@example
|
|
|
|
;; @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>
|
2000-01-16 00:29:04 +00:00
|
|
|
;; @r{Moving and deleting the overlay does not change its properties.}
|
1999-12-03 19:11:12 +00:00
|
|
|
(overlay-get foo 'happy)
|
|
|
|
@result{} t
|
|
|
|
@end example
|
|
|
|
|
|
|
|
@node Finding Overlays
|
|
|
|
@subsection Searching for Overlays
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@defun overlays-at pos
|
1999-12-03 19:11:12 +00:00
|
|
|
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:
|
|
|
|
|
|
|
|
@smallexample
|
|
|
|
(defun find-overlays-specifying (prop)
|
|
|
|
(let ((overlays (overlays-at (point)))
|
|
|
|
found)
|
|
|
|
(while overlays
|
2001-04-03 14:28:29 +00:00
|
|
|
(let ((overlay (car overlays)))
|
1999-12-03 19:11:12 +00:00
|
|
|
(if (overlay-get overlay prop)
|
|
|
|
(setq found (cons overlay found))))
|
|
|
|
(setq overlays (cdr overlays)))
|
|
|
|
found))
|
|
|
|
@end smallexample
|
1994-03-30 18:36:47 +00:00
|
|
|
@end defun
|
|
|
|
|
1998-02-28 01:53:53 +00:00
|
|
|
@defun overlays-in beg end
|
|
|
|
This function returns a list of the overlays that overlap the region
|
|
|
|
@var{beg} 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
|
1999-12-03 19:11:12 +00:00
|
|
|
they are located at @var{beg}, or strictly between @var{beg} and @var{end}.
|
1998-02-28 01:53:53 +00:00
|
|
|
@end defun
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@defun next-overlay-change pos
|
|
|
|
This function returns the buffer position of the next beginning or end
|
|
|
|
of an overlay, after @var{pos}.
|
|
|
|
@end defun
|
|
|
|
|
1995-06-05 12:23:13 +00:00
|
|
|
@defun previous-overlay-change pos
|
|
|
|
This function returns the buffer position of the previous beginning or
|
|
|
|
end of an overlay, before @var{pos}.
|
|
|
|
@end defun
|
|
|
|
|
1999-12-03 19:11:12 +00:00
|
|
|
Here's an easy way to use @code{next-overlay-change} to search for the
|
|
|
|
next character which gets a non-@code{nil} @code{happy} property from
|
|
|
|
either its overlays or its text properties (@pxref{Property Search}):
|
|
|
|
|
|
|
|
@smallexample
|
|
|
|
(defun find-overlay-prop (prop)
|
|
|
|
(save-excursion
|
|
|
|
(while (and (not (eobp))
|
|
|
|
(not (get-char-property (point) 'happy)))
|
|
|
|
(goto-char (min (next-overlay-change (point))
|
|
|
|
(next-single-property-change (point) 'happy))))
|
|
|
|
(point)))
|
|
|
|
@end smallexample
|
|
|
|
|
1998-02-28 01:53:53 +00:00
|
|
|
@node Width
|
|
|
|
@section Width
|
|
|
|
|
|
|
|
Since not all characters have the same width, these functions let you
|
1998-04-20 17:43:57 +00:00
|
|
|
check the width of a character. @xref{Primitive Indent}, and
|
|
|
|
@ref{Screen Lines}, for related functions.
|
1998-02-28 01:53:53 +00:00
|
|
|
|
|
|
|
@defun 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.
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
@defun 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.
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
@defun truncate-string-to-width string width &optional start-column padding
|
|
|
|
This function returns the part of @var{string} that fits within
|
|
|
|
@var{width} columns, as a new string.
|
|
|
|
|
|
|
|
If @var{string} does not reach @var{width}, then the result ends where
|
|
|
|
@var{string} 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 non-@code{nil}, then the first @var{start-column} columns of
|
|
|
|
the string are omitted from the value. If one multi-column character in
|
|
|
|
@var{string} extends across the column @var{start-column}, that
|
|
|
|
character is not included.
|
|
|
|
|
|
|
|
The optional argument @var{padding}, if non-@code{nil}, 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
|
|
|
|
@var{string} extends across the column @var{start-column}.
|
|
|
|
|
|
|
|
@example
|
|
|
|
(truncate-string-to-width "\tab\t" 12 4)
|
|
|
|
@result{} "ab"
|
|
|
|
(truncate-string-to-width "\tab\t" 12 4 ?\ )
|
|
|
|
@result{} " ab "
|
|
|
|
@end example
|
|
|
|
@end defun
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@node Faces
|
|
|
|
@section Faces
|
2001-10-30 00:28:01 +00:00
|
|
|
@cindex faces
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
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.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
|
|
|
@cindex face id
|
1998-04-20 17:43:57 +00:00
|
|
|
Each face has its own @dfn{face number}, which distinguishes faces at
|
1999-09-17 06:59:04 +00:00
|
|
|
low levels within Emacs. However, for most purposes, you refer to
|
1994-03-30 18:36:47 +00:00
|
|
|
faces in Lisp programs by their names.
|
|
|
|
|
1995-06-05 12:23:13 +00:00
|
|
|
@defun facep object
|
|
|
|
This function returns @code{t} if @var{object} is a face name symbol (or
|
|
|
|
if it is a vector of the kind used internally to record face data). It
|
|
|
|
returns @code{nil} otherwise.
|
|
|
|
@end defun
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
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.
|
|
|
|
|
|
|
|
@menu
|
|
|
|
* Standard Faces:: The faces Emacs normally comes with.
|
1998-04-20 17:43:57 +00:00
|
|
|
* Defining Faces:: How to define a face with @code{defface}.
|
1999-09-17 06:59:04 +00:00
|
|
|
* Face Attributes:: What is in a face?
|
|
|
|
* Attribute Functions:: Functions to examine and set face attributes.
|
|
|
|
* Merging Faces:: How Emacs combines the faces specified for a character.
|
|
|
|
* Font Selection:: Finding the best available font for a face.
|
1994-03-30 18:36:47 +00:00
|
|
|
* Face Functions:: How to define and examine faces.
|
1999-09-17 06:59:04 +00:00
|
|
|
* 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.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end menu
|
|
|
|
|
|
|
|
@node Standard Faces
|
|
|
|
@subsection Standard Faces
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
This table lists all the standard faces and their uses. Most of them
|
|
|
|
are used for displaying certain parts of the frames or certain kinds of
|
|
|
|
text; you can control how those places look by customizing these faces.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
|
|
|
@table @code
|
|
|
|
@item default
|
|
|
|
@kindex default @r{(face name)}
|
|
|
|
This face is used for ordinary text.
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@item mode-line
|
|
|
|
@kindex mode-line @r{(face name)}
|
2002-02-12 18:57:31 +00:00
|
|
|
This face is used for the mode line of the selected window, and for
|
|
|
|
menu bars when toolkit menus are not used---but only if
|
|
|
|
@code{mode-line-inverse-video} is non-@code{nil}.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@item modeline
|
|
|
|
@kindex modeline @r{(face name)}
|
1999-09-17 06:59:04 +00:00
|
|
|
This is an alias for the @code{mode-line} face, for compatibility with
|
|
|
|
old Emacs versions.
|
|
|
|
|
2002-02-12 18:57:31 +00:00
|
|
|
@item mode-line-inactive
|
|
|
|
@kindex mode-line-inactive @r{(face name)}
|
|
|
|
This face is used for mode lines of non-selected windows.
|
2002-02-14 01:38:49 +00:00
|
|
|
This face inherits from @code{mode-line}, so changes
|
|
|
|
in that face affect all windows.
|
2002-02-12 18:57:31 +00:00
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@item header-line
|
|
|
|
@kindex header-line @r{(face name)}
|
|
|
|
This face is used for the header lines of windows that have them.
|
|
|
|
|
1999-10-05 23:26:05 +00:00
|
|
|
@item menu
|
|
|
|
This face controls the display of menus, both their colors and their
|
|
|
|
font. (This works only on certain systems.)
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@item fringe
|
|
|
|
@kindex fringe @r{(face name)}
|
|
|
|
This face controls the colors of window fringes, the thin areas on
|
|
|
|
either side that are used to display continuation and truncation glyphs.
|
|
|
|
|
2002-02-03 17:38:25 +00:00
|
|
|
@item minibuffer-prompt
|
|
|
|
@kindex minibuffer-prompt @r{(face name)}
|
|
|
|
@vindex minibuffer-prompt-properties
|
|
|
|
This face is used for the text of minibuffer prompts. By default,
|
|
|
|
Emacs automatically adds this face to the value of
|
|
|
|
@code{minibuffer-prompt-properties}, which is a list of text
|
|
|
|
properties used to display the prompt text.
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@item scroll-bar
|
|
|
|
@kindex scroll-bar @r{(face name)}
|
|
|
|
This face controls the colors for display of scroll bars.
|
|
|
|
|
|
|
|
@item tool-bar
|
|
|
|
@kindex tool-bar @r{(face name)}
|
|
|
|
This face is used for display of the tool bar, if any.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
|
|
|
@item region
|
|
|
|
@kindex region @r{(face name)}
|
|
|
|
This face is used for highlighting the region in Transient Mark mode.
|
|
|
|
|
|
|
|
@item secondary-selection
|
|
|
|
@kindex secondary-selection @r{(face name)}
|
|
|
|
This face is used to show any secondary selection you have made.
|
|
|
|
|
|
|
|
@item highlight
|
|
|
|
@kindex highlight @r{(face name)}
|
|
|
|
This face is meant to be used for highlighting for various purposes.
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@item trailing-whitespace
|
|
|
|
@kindex trailing-whitespace @r{(face name)}
|
1999-10-05 23:26:05 +00:00
|
|
|
This face is used to display excess whitespace at the end of a line,
|
|
|
|
if @code{show-trailing-whitespace} is non-@code{nil}.
|
1999-09-17 06:59:04 +00:00
|
|
|
@end table
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
In contrast, these faces are provided to change the appearance of text
|
|
|
|
in specific ways. You can use them on specific text, when you want
|
|
|
|
the effects they produce.
|
|
|
|
|
|
|
|
@table @code
|
1994-03-30 18:36:47 +00:00
|
|
|
@item bold
|
|
|
|
@kindex bold @r{(face name)}
|
|
|
|
This face uses a bold font, if possible. It uses the bold variant of
|
|
|
|
the frame's font, if it has one. It's up to you to choose a default
|
|
|
|
font that has a bold variant, if you want to use one.
|
|
|
|
|
|
|
|
@item italic
|
|
|
|
@kindex italic @r{(face name)}
|
|
|
|
This face uses the italic variant of the frame's font, if it has one.
|
|
|
|
|
|
|
|
@item bold-italic
|
|
|
|
@kindex bold-italic @r{(face name)}
|
|
|
|
This face uses the bold italic variant of the frame's font, if it has
|
|
|
|
one.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
@item underline
|
|
|
|
@kindex underline @r{(face name)}
|
|
|
|
This face underlines text.
|
|
|
|
|
2001-07-04 06:22:15 +00:00
|
|
|
@item fixed-pitch
|
|
|
|
@kindex fixed-pitch @r{(face name)}
|
1999-09-17 06:59:04 +00:00
|
|
|
This face forces use of a particular fixed-width font.
|
|
|
|
|
2001-07-04 06:22:15 +00:00
|
|
|
@item variable-pitch
|
|
|
|
@kindex variable-pitch @r{(face name)}
|
1999-09-17 06:59:04 +00:00
|
|
|
This face forces use of a particular variable-width font. It's
|
1999-10-05 23:26:05 +00:00
|
|
|
reasonable to customize this to use a different variable-width font, if
|
1999-09-17 06:59:04 +00:00
|
|
|
you like, but you should not make it a fixed-width font.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end table
|
|
|
|
|
1999-10-05 23:26:05 +00:00
|
|
|
@defvar show-trailing-whitespace
|
|
|
|
@tindex show-trailing-whitespace
|
|
|
|
If this variable is non-@code{nil}, Emacs uses the
|
|
|
|
@code{trailing-whitespace} face to display any spaces and tabs at the
|
|
|
|
end of a line.
|
|
|
|
@end defvar
|
|
|
|
|
1998-04-20 17:43:57 +00:00
|
|
|
@node Defining Faces
|
1998-05-19 03:45:57 +00:00
|
|
|
@subsection Defining Faces
|
1998-04-20 17:43:57 +00:00
|
|
|
|
|
|
|
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}).
|
|
|
|
|
|
|
|
@defmac defface face spec doc [keyword value]...
|
1999-10-05 23:26:05 +00:00
|
|
|
This declares @var{face} as a customizable face that defaults according
|
|
|
|
to @var{spec}. You should not quote the symbol @var{face}. The
|
|
|
|
argument @var{doc} specifies the face documentation. The keywords you
|
|
|
|
can use in @code{defface} are the same ones that are meaningful in both
|
|
|
|
@code{defgroup} and @code{defcustom} (@pxref{Common Keywords}).
|
1998-04-20 17:43:57 +00:00
|
|
|
|
|
|
|
When @code{defface} executes, it defines the face according to
|
1998-05-19 03:45:57 +00:00
|
|
|
@var{spec}, then uses any customizations that were read from the
|
1999-10-05 23:26:05 +00:00
|
|
|
init file (@pxref{Init File}) to override that specification.
|
1998-04-20 17:43:57 +00:00
|
|
|
|
|
|
|
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
|
1999-10-05 23:26:05 +00:00
|
|
|
the form @code{(@var{display} @var{atts})}. Each element's @sc{car},
|
|
|
|
@var{display}, specifies a class of terminals. The element's second element,
|
1998-04-20 17:43:57 +00:00
|
|
|
@var{atts}, 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 @code{custom-face-attributes}.
|
|
|
|
|
|
|
|
The @var{display} part of an element of @var{spec} determines which
|
|
|
|
frames the element applies to. If more than one element of @var{spec}
|
|
|
|
matches a given frame, the first matching element is the only one used
|
|
|
|
for that frame. There are two possibilities for @var{display}:
|
|
|
|
|
|
|
|
@table @asis
|
|
|
|
@item @code{t}
|
|
|
|
This element of @var{spec} matches all frames. Therefore, any
|
|
|
|
subsequent elements of @var{spec} are never used. Normally
|
|
|
|
@code{t} is used in the last (or only) element of @var{spec}.
|
|
|
|
|
1998-05-19 03:45:57 +00:00
|
|
|
@item a list
|
1998-05-26 18:56:56 +00:00
|
|
|
If @var{display} is a list, each element should have the form
|
1998-04-20 17:43:57 +00:00
|
|
|
@code{(@var{characteristic} @var{value}@dots{})}. Here
|
|
|
|
@var{characteristic} specifies a way of classifying frames, and the
|
|
|
|
@var{value}s are possible classifications which @var{display} should
|
|
|
|
apply to. Here are the possible values of @var{characteristic}:
|
|
|
|
|
|
|
|
@table @code
|
|
|
|
@item type
|
2000-10-24 06:21:50 +00:00
|
|
|
The kind of window system the frame uses---either @code{graphic} (any
|
|
|
|
graphics-capable display), @code{x}, @code{pc} (for the MS-DOS console),
|
|
|
|
@code{w32} (for MS Windows 9X/NT), or @code{tty} (a non-graphics-capable
|
|
|
|
display).
|
1998-04-20 17:43:57 +00:00
|
|
|
|
|
|
|
@item class
|
|
|
|
What kinds of colors the frame supports---either @code{color},
|
|
|
|
@code{grayscale}, or @code{mono}.
|
|
|
|
|
|
|
|
@item background
|
1998-05-26 18:56:56 +00:00
|
|
|
The kind of background---either @code{light} or @code{dark}.
|
2002-06-11 01:50:36 +00:00
|
|
|
|
|
|
|
@item supports
|
2002-07-04 06:43:15 +00:00
|
|
|
Whether or not the frame can display the face attributes given in
|
|
|
|
@var{value}@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}.
|
1998-04-20 17:43:57 +00:00
|
|
|
@end 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
|
|
|
|
@var{display} 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
|
|
|
|
@var{display}.
|
|
|
|
@end table
|
|
|
|
@end defmac
|
|
|
|
|
1999-10-05 23:26:05 +00:00
|
|
|
Here's how the standard face @code{region} is defined:
|
1998-04-20 17:43:57 +00:00
|
|
|
|
|
|
|
@example
|
1999-10-05 23:26:05 +00:00
|
|
|
@group
|
1998-04-20 17:43:57 +00:00
|
|
|
(defface region
|
1999-10-05 23:26:05 +00:00
|
|
|
`((((type tty) (class color))
|
|
|
|
(:background "blue" :foreground "white"))
|
|
|
|
@end group
|
|
|
|
(((type tty) (class mono))
|
|
|
|
(:inverse-video t))
|
|
|
|
(((class color) (background dark))
|
|
|
|
(:background "blue"))
|
|
|
|
(((class color) (background light))
|
|
|
|
(:background "lightblue"))
|
|
|
|
(t (:background "gray")))
|
|
|
|
@group
|
|
|
|
"Basic face for highlighting the region."
|
|
|
|
:group 'basic-faces)
|
|
|
|
@end group
|
1998-04-20 17:43:57 +00:00
|
|
|
@end example
|
|
|
|
|
|
|
|
Internally, @code{defface} uses the symbol property
|
|
|
|
@code{face-defface-spec} to record the face attributes specified in
|
|
|
|
@code{defface}, @code{saved-face} for the attributes saved by the user
|
|
|
|
with the customization buffer, and @code{face-documentation} for the
|
|
|
|
documentation string.
|
|
|
|
|
1998-05-26 18:56:56 +00:00
|
|
|
@defopt frame-background-mode
|
|
|
|
This option, if non-@code{nil}, 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.
|
|
|
|
@end defopt
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@node Face Attributes
|
|
|
|
@subsection Face Attributes
|
|
|
|
@cindex face attributes
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
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
|
1999-10-05 23:26:05 +00:00
|
|
|
mean. Note that in general, more than one face can be specified for a
|
|
|
|
given piece of text; when that happens, the attributes of all the faces
|
|
|
|
are merged to specify how to display the text. @xref{Merging Faces}.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
In Emacs 21, 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.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1999-10-05 23:26:05 +00:00
|
|
|
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},
|
|
|
|
@code{:height}, @code{:weight}, and @code{:slant} correspond to parts of
|
|
|
|
an X Logical Font Descriptor.)
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@table @code
|
|
|
|
@item :family
|
|
|
|
Font family name, or fontset name (@pxref{Fontsets}). If you specify a
|
1999-10-05 23:26:05 +00:00
|
|
|
font family name, the wild-card characters @samp{*} and @samp{?} are
|
|
|
|
allowed.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
@item :width
|
|
|
|
Relative proportionate width, also known as the character set width or
|
|
|
|
set width. This should be one of the symbols @code{ultra-condensed},
|
|
|
|
@code{extra-condensed}, @code{condensed}, @code{semi-condensed},
|
|
|
|
@code{normal}, @code{semi-expanded}, @code{expanded},
|
|
|
|
@code{extra-expanded}, or @code{ultra-expanded}.
|
|
|
|
|
|
|
|
@item :height
|
2000-10-03 01:55:27 +00:00
|
|
|
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.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
@item :weight
|
|
|
|
Font weight---a symbol from this series (from most dense to most faint):
|
|
|
|
@code{ultra-bold}, @code{extra-bold}, @code{bold}, @code{semi-bold},
|
|
|
|
@code{normal}, @code{semi-light}, @code{light}, @code{extra-light},
|
1999-10-05 23:26:05 +00:00
|
|
|
or @code{ultra-light}.
|
1999-09-24 13:52:46 +00:00
|
|
|
|
1999-10-05 23:26:05 +00:00
|
|
|
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).
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@item :slant
|
|
|
|
Font slant---one of the symbols @code{italic}, @code{oblique}, @code{normal},
|
|
|
|
@code{reverse-italic}, or @code{reverse-oblique}.
|
1999-09-24 13:52:46 +00:00
|
|
|
|
|
|
|
On a text-only terminal, slanted text is displayed as half-bright, if
|
|
|
|
the terminal supports the feature.
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@item :foreground
|
|
|
|
Foreground color, a string.
|
|
|
|
|
|
|
|
@item :background
|
|
|
|
Background color, a string.
|
|
|
|
|
|
|
|
@item :inverse-video
|
|
|
|
Whether or not characters should be displayed in inverse video. The
|
|
|
|
value should be @code{t} (yes) or @code{nil} (no).
|
|
|
|
|
|
|
|
@item :stipple
|
1999-10-05 23:26:05 +00:00
|
|
|
The background stipple, a bitmap.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
1999-10-05 23:26:05 +00:00
|
|
|
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}.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
2001-10-25 15:30:00 +00:00
|
|
|
Alternatively, the value can specify the bitmap directly, with a list
|
|
|
|
of the form @code{(@var{width} @var{height} @var{data})}. Here,
|
|
|
|
@var{width} and @var{height} specify the size in pixels, and
|
|
|
|
@var{data} 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.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
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.
|
|
|
|
|
|
|
|
@item :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.
|
|
|
|
|
|
|
|
@item :overline
|
|
|
|
Whether or not characters should be overlined, and in what color.
|
|
|
|
The value is used like that of @code{:underline}.
|
|
|
|
|
|
|
|
@item :strike-through
|
|
|
|
Whether or not characters should be strike-through, and in what
|
|
|
|
color. The value is used like that of @code{:underline}.
|
|
|
|
|
2000-10-03 01:55:27 +00:00
|
|
|
@item :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.
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@item :box
|
|
|
|
Whether or not a box should be drawn around characters, its color, the
|
1999-10-05 23:26:05 +00:00
|
|
|
width of the box lines, and 3D appearance.
|
1999-09-17 06:59:04 +00:00
|
|
|
@end table
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
Here are the possible values of the @code{:box} attribute, and what
|
|
|
|
they mean:
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@table @asis
|
|
|
|
@item @code{nil}
|
|
|
|
Don't draw a box.
|
1995-06-06 19:21:15 +00:00
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@item @code{t}
|
|
|
|
Draw a box with lines of width 1, in the foreground color.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@item @var{color}
|
|
|
|
Draw a box with lines of width 1, in color @var{color}.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@item @code{(:line-width @var{width} :color @var{color} :style @var{style})}
|
|
|
|
This way you can explicitly specify all aspects of the box. The value
|
|
|
|
@var{width} specifies the width of the lines to draw; it defaults to 1.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
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.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
The value @var{style} specifies whether to draw a 3D box. If it is
|
|
|
|
@code{released-button}, 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.
|
|
|
|
@end table
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
The attributes @code{:overline}, @code{:strike-through} and
|
|
|
|
@code{:box} are new in Emacs 21. The attributes @code{:family},
|
|
|
|
@code{:height}, @code{:width}, @code{:weight}, @code{:slant} are also
|
1999-10-05 23:26:05 +00:00
|
|
|
new; previous versions used the following attributes, now semi-obsolete,
|
|
|
|
to specify some of the same information:
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@table @code
|
|
|
|
@item :font
|
1999-10-05 23:26:05 +00:00
|
|
|
This attribute specifies the font name.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@item :bold
|
|
|
|
A non-@code{nil} value specifies a bold font.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@item :italic
|
|
|
|
A non-@code{nil} value specifies an italic font.
|
|
|
|
@end table
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
For compatibility, you can still set these ``attributes'' in Emacs 21,
|
|
|
|
even though they are not real face attributes. Here is what that does:
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@table @code
|
|
|
|
@item :font
|
1999-10-05 23:26:05 +00:00
|
|
|
You can specify an X font name as the ``value'' of this ``attribute'';
|
|
|
|
that sets the @code{:family}, @code{:width}, @code{:height},
|
|
|
|
@code{:weight}, and @code{:slant} attributes according to the font name.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
If the value is a pattern with wildcards, the first font that matches
|
|
|
|
the pattern is used to set these attributes.
|
|
|
|
|
|
|
|
@item :bold
|
|
|
|
A non-@code{nil} makes the face bold; @code{nil} makes it normal.
|
|
|
|
This actually works by setting the @code{:weight} attribute.
|
|
|
|
|
|
|
|
@item :italic
|
|
|
|
A non-@code{nil} makes the face italic; @code{nil} makes it normal.
|
|
|
|
This actually works by setting the @code{:slant} attribute.
|
|
|
|
@end table
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@defvar x-bitmap-file-path
|
|
|
|
This variable specifies a list of directories for searching
|
|
|
|
for bitmap files, for the @code{:stipple} attribute.
|
|
|
|
@end defvar
|
|
|
|
|
1999-10-07 20:27:52 +00:00
|
|
|
@defun bitmap-spec-p object
|
2002-01-21 23:04:26 +00:00
|
|
|
This returns @code{t} if @var{object} is a valid bitmap specification,
|
|
|
|
suitable for use with @code{:stipple} (see above). It returns
|
|
|
|
@code{nil} otherwise.
|
1999-10-05 23:26:05 +00:00
|
|
|
@end defun
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@node Attribute Functions
|
|
|
|
@subsection Face Attribute Functions
|
1994-03-30 18:36:47 +00:00
|
|
|
|
|
|
|
You can modify the attributes of an existing face with the following
|
|
|
|
functions. If you specify @var{frame}, they affect just that frame;
|
|
|
|
otherwise, they affect all frames as well as the defaults that apply to
|
|
|
|
new frames.
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@tindex set-face-attribute
|
|
|
|
@defun set-face-attribute face frame &rest arguments
|
|
|
|
This function sets one or more attributes of face @var{face}
|
|
|
|
for frame @var{frame}. If @var{frame} is @code{nil}, it sets
|
|
|
|
the attribute for all frames, and the defaults for new frames.
|
|
|
|
|
|
|
|
The extra arguments @var{arguments} specify the attributes to set, and
|
|
|
|
the values for them. They should consist of alternating attribute names
|
1999-10-05 23:26:05 +00:00
|
|
|
(such as @code{:family} or @code{:underline}) and corresponding values.
|
1999-09-17 06:59:04 +00:00
|
|
|
Thus,
|
|
|
|
|
|
|
|
@example
|
|
|
|
(set-face-attribute 'foo nil
|
2002-07-29 01:58:43 +00:00
|
|
|
:width 'extended
|
|
|
|
:weight 'bold
|
1999-09-17 06:59:04 +00:00
|
|
|
:underline "red")
|
|
|
|
@end example
|
|
|
|
|
|
|
|
@noindent
|
|
|
|
sets the attributes @code{:width}, @code{:weight} and @code{:underline}
|
|
|
|
to the corresponding values.
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
@tindex face-attribute
|
2002-07-07 23:43:25 +00:00
|
|
|
@defun face-attribute face attribute &optional frame inherit
|
1999-09-17 06:59:04 +00:00
|
|
|
This returns the value of the @var{attribute} attribute of face
|
|
|
|
@var{face} on @var{frame}. If @var{frame} is @code{nil},
|
2001-09-23 18:56:28 +00:00
|
|
|
that means the selected frame (@pxref{Input Focus}).
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
If @var{frame} is @code{t}, the value is the default for
|
|
|
|
@var{face} for new frames.
|
|
|
|
|
2002-07-07 23:43:25 +00:00
|
|
|
If @var{inherit} is nil, only attributes directly defined by
|
|
|
|
@var{face} are considered, so the return value may be
|
|
|
|
@code{unspecified}, or a relative value. If @var{inherit} is non-nil,
|
|
|
|
@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 @var{inherit} 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).
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
For example,
|
|
|
|
|
|
|
|
@example
|
|
|
|
(face-attribute 'bold :weight)
|
|
|
|
@result{} bold
|
|
|
|
@end example
|
|
|
|
@end defun
|
|
|
|
|
1999-10-05 23:26:05 +00:00
|
|
|
The functions above did not exist before Emacs 21. For compatibility
|
|
|
|
with older Emacs versions, you can use the following functions to set
|
1999-09-17 06:59:04 +00:00
|
|
|
and examine the face attributes which existed in those versions.
|
|
|
|
|
2002-07-07 23:43:25 +00:00
|
|
|
@tindex face-attribute-relative-p
|
|
|
|
@defun face-attribute-relative-p attribute value
|
|
|
|
This function returns non-@code{nil} if @var{value}, when used as a
|
|
|
|
the value of the face attribute @var{attribute}, is relative (that is,
|
|
|
|
if it modifies an underlying or inherited value of @var{attribute}).
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
@tindex merge-face-attribute
|
|
|
|
@defun merge-face-attribute attribute value1 value2
|
|
|
|
If @var{value1} is a relative value for the face attribute
|
|
|
|
@var{attribute}, returns it merged with the underlying value
|
|
|
|
@var{value2}; otherwise, if @var{value1} is an absolute value for the
|
|
|
|
face a attribute @var{attribute}, returns @var{value1} unchanged.
|
|
|
|
@end defun
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@defun set-face-foreground face color &optional frame
|
|
|
|
@defunx set-face-background face color &optional frame
|
1994-09-22 22:00:06 +00:00
|
|
|
These functions set the foreground (or background, respectively) color
|
|
|
|
of face @var{face} to @var{color}. The argument @var{color} should be a
|
1994-03-30 18:36:47 +00:00
|
|
|
string, the name of a color.
|
1995-06-06 19:21:15 +00:00
|
|
|
|
|
|
|
Certain shades of gray are implemented by stipple patterns on
|
|
|
|
black-and-white screens.
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
@defun set-face-stipple face pattern &optional frame
|
2002-01-21 23:04:26 +00:00
|
|
|
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.
|
1995-06-06 19:21:15 +00:00
|
|
|
|
|
|
|
Normally there is no need to pay attention to stipple patterns, because
|
|
|
|
they are used automatically to handle certain shades of gray.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end defun
|
|
|
|
|
|
|
|
@defun set-face-font face font &optional frame
|
1999-09-17 06:59:04 +00:00
|
|
|
This function sets the font of face @var{face}.
|
|
|
|
|
|
|
|
In Emacs 21, this actually sets the attributes @code{:family},
|
|
|
|
@code{:width}, @code{:height}, @code{:weight}, and @code{:slant}
|
|
|
|
according to the font name @var{font}.
|
|
|
|
|
|
|
|
In Emacs 20, this sets the font attribute. Once you set the font
|
1998-05-19 03:45:57 +00:00
|
|
|
explicitly, the bold and italic attributes cease to have any effect,
|
1999-09-17 06:59:04 +00:00
|
|
|
because the precise font that you specified is used.
|
1997-06-13 00:52:37 +00:00
|
|
|
@end defun
|
|
|
|
|
1998-02-28 01:53:53 +00:00
|
|
|
@defun set-face-bold-p face bold-p &optional frame
|
1999-09-17 06:59:04 +00:00
|
|
|
This function specifies whether @var{face} should be bold. If
|
|
|
|
@var{bold-p} is non-@code{nil}, that means yes; @code{nil} means no.
|
|
|
|
|
|
|
|
In Emacs 21, this sets the @code{:weight} attribute.
|
|
|
|
In Emacs 20, it sets the @code{:bold} attribute.
|
1997-06-13 00:52:37 +00:00
|
|
|
@end defun
|
|
|
|
|
1998-02-28 01:53:53 +00:00
|
|
|
@defun set-face-italic-p face italic-p &optional frame
|
1999-09-17 06:59:04 +00:00
|
|
|
This function specifies whether @var{face} should be italic. If
|
|
|
|
@var{italic-p} is non-@code{nil}, that means yes; @code{nil} means no.
|
|
|
|
|
|
|
|
In Emacs 21, this sets the @code{:slant} attribute.
|
|
|
|
In Emacs 20, it sets the @code{:italic} attribute.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end defun
|
|
|
|
|
1998-04-20 17:43:57 +00:00
|
|
|
@defun set-face-underline-p face underline-p &optional frame
|
|
|
|
This function sets the underline attribute of face @var{face}.
|
|
|
|
Non-@code{nil} means do underline; @code{nil} means don't.
|
|
|
|
@end defun
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@defun invert-face face &optional frame
|
1999-09-17 06:59:04 +00:00
|
|
|
This function inverts the @code{:inverse-video} attribute of face
|
|
|
|
@var{face}. If the attribute is @code{nil}, this function sets it to
|
|
|
|
@code{t}, and vice versa.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end defun
|
|
|
|
|
|
|
|
These functions examine the attributes of a face. If you don't
|
|
|
|
specify @var{frame}, they refer to the default data for new frames.
|
1999-10-05 23:26:05 +00:00
|
|
|
They return the symbol @code{unspecified} if the face doesn't define any
|
|
|
|
value for that attribute.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
2002-07-07 23:58:31 +00:00
|
|
|
@defun face-foreground face &optional frame inherit
|
1994-03-30 18:36:47 +00:00
|
|
|
@defunx face-background face &optional frame
|
1994-09-22 22:00:06 +00:00
|
|
|
These functions return the foreground color (or background color,
|
|
|
|
respectively) of face @var{face}, as a string.
|
2002-07-07 23:58:31 +00:00
|
|
|
|
|
|
|
If @var{inherit} is nil, only a color directly defined by the face is
|
|
|
|
returned. If @var{inherit} is non-nil, 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 color is found. To ensure that the return value is always
|
|
|
|
specified, use a value of @code{default} for @var{inherit}.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end defun
|
|
|
|
|
2002-07-07 23:58:31 +00:00
|
|
|
@defun face-stipple face &optional frame inherit
|
1995-06-06 19:21:15 +00:00
|
|
|
This function returns the name of the background stipple pattern of face
|
|
|
|
@var{face}, or @code{nil} if it doesn't have one.
|
2002-07-07 23:58:31 +00:00
|
|
|
|
|
|
|
If @var{inherit} is nil, only a stipple directly defined by the face
|
|
|
|
is returned. If @var{inherit} is non-nil, 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 @var{inherit}.
|
1995-06-06 19:21:15 +00:00
|
|
|
@end defun
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@defun face-font face &optional frame
|
|
|
|
This function returns the name of the font of face @var{face}.
|
|
|
|
@end defun
|
|
|
|
|
1998-02-28 01:53:53 +00:00
|
|
|
@defun face-bold-p face &optional frame
|
1999-09-17 06:59:04 +00:00
|
|
|
This function returns @code{t} if @var{face} is bold---that is, if it is
|
|
|
|
bolder than normal. It returns @code{nil} otherwise.
|
1998-02-28 01:53:53 +00:00
|
|
|
@end defun
|
|
|
|
|
|
|
|
@defun face-italic-p face &optional frame
|
1999-09-17 06:59:04 +00:00
|
|
|
This function returns @code{t} if @var{face} is italic or oblique,
|
|
|
|
@code{nil} otherwise.
|
1998-02-28 01:53:53 +00:00
|
|
|
@end defun
|
|
|
|
|
1998-04-20 17:43:57 +00:00
|
|
|
@defun face-underline-p face &optional frame
|
1999-09-17 06:59:04 +00:00
|
|
|
This function returns the @code{:underline} attribute of face @var{face}.
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
@defun face-inverse-video-p face &optional frame
|
|
|
|
This function returns the @code{:inverse-video} attribute of face @var{face}.
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
@node Merging Faces
|
|
|
|
@subsection Merging Faces for Display
|
|
|
|
|
|
|
|
Here are the ways to specify which faces to use for display of text:
|
|
|
|
|
|
|
|
@itemize @bullet
|
|
|
|
@item
|
|
|
|
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.)
|
|
|
|
|
|
|
|
For a mode line or header line, the face @code{modeline} or
|
|
|
|
@code{header-line} is used just before @code{default}.
|
|
|
|
|
|
|
|
@item
|
|
|
|
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.
|
|
|
|
|
|
|
|
@item
|
|
|
|
With overlays. An overlay can have @code{face} and @code{mouse-face}
|
|
|
|
properties too; they apply to all the text covered by the overlay.
|
|
|
|
|
|
|
|
@item
|
|
|
|
With a region that is active. In Transient Mark mode, the region is
|
|
|
|
highlighted with the face @code{region} (@pxref{Standard Faces}).
|
|
|
|
|
|
|
|
@item
|
|
|
|
With special glyphs. Each glyph can specify a particular face
|
|
|
|
number. @xref{Glyphs}.
|
|
|
|
@end itemize
|
|
|
|
|
|
|
|
If these various sources together specify more than one face for a
|
|
|
|
particular character, Emacs merges the attributes of the various faces
|
|
|
|
specified. The attributes of the faces of special glyphs come first;
|
|
|
|
then comes the face for region highlighting, if appropriate;
|
|
|
|
then come attributes of faces from overlays, followed by those from text
|
|
|
|
properties, and last the default face.
|
|
|
|
|
|
|
|
When multiple overlays cover one character, an overlay with higher
|
|
|
|
priority overrides those with lower priority. @xref{Overlays}.
|
|
|
|
|
|
|
|
In Emacs 20, if an attribute such as the font or a color is not
|
|
|
|
specified in any of the above ways, the frame's own font or color is
|
|
|
|
used. In newer Emacs versions, this cannot happen, because the
|
|
|
|
@code{default} face specifies all attributes---in fact, the frame's own
|
|
|
|
font and colors are synonymous with those of the default face.
|
|
|
|
|
|
|
|
@node Font Selection
|
|
|
|
@subsection 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.
|
|
|
|
|
|
|
|
For multibyte characters, typically each font covers only one
|
|
|
|
character set. So each character set (@pxref{Character Sets}) specifies
|
|
|
|
a registry and encoding to use, with the character set's
|
|
|
|
@code{x-charset-registry} property. Its value is a string containing
|
|
|
|
the registry and the encoding, with a dash between them:
|
|
|
|
|
|
|
|
@example
|
|
|
|
(plist-get (charset-plist 'latin-iso8859-1)
|
|
|
|
'x-charset-registry)
|
|
|
|
@result{} "ISO8859-1"
|
|
|
|
@end example
|
|
|
|
|
|
|
|
Unibyte text does not have character sets, so displaying a unibyte
|
|
|
|
character takes the registry and encoding from the variable
|
|
|
|
@code{face-default-registry}.
|
|
|
|
|
|
|
|
@defvar face-default-registry
|
|
|
|
This variable specifies which registry and encoding to use in choosing
|
|
|
|
fonts for unibyte characters. The value is initialized at Emacs startup
|
|
|
|
time from the font the user specified for Emacs.
|
|
|
|
@end defvar
|
|
|
|
|
|
|
|
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
|
2000-02-09 23:54:58 +00:00
|
|
|
``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.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
@defvar face-font-selection-order
|
|
|
|
@tindex face-font-selection-order
|
|
|
|
This variable specifies the order of importance of the face attributes
|
|
|
|
@code{: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
|
|
|
|
@code{italic} face will use a non-italic font that is similar to the
|
|
|
|
default one. But if you put @code{:slant} before @code{:height}, the
|
|
|
|
@code{italic} face will use an italic font, even if its height is not
|
|
|
|
quite right.
|
|
|
|
@end defvar
|
|
|
|
|
2000-11-10 15:00:47 +00:00
|
|
|
@defvar face-font-family-alternatives
|
|
|
|
@tindex face-font-family-alternatives
|
1999-09-17 06:59:04 +00:00
|
|
|
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:
|
|
|
|
|
|
|
|
@example
|
|
|
|
(@var{family} @var{alternate-families}@dots{})
|
|
|
|
@end 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.
|
2000-11-10 15:00:47 +00:00
|
|
|
@end defvar
|
|
|
|
|
|
|
|
@defvar face-font-registry-alternatives
|
|
|
|
@tindex 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:
|
|
|
|
|
|
|
|
@example
|
|
|
|
(@var{registry} @var{alternate-registries}@dots{})
|
|
|
|
@end 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.
|
1999-09-17 06:59:04 +00:00
|
|
|
@end 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.
|
|
|
|
|
|
|
|
@defvar scalable-fonts-allowed
|
|
|
|
@tindex scalable-fonts-allowed
|
|
|
|
This variable controls which scalable fonts to use. A value of
|
|
|
|
@code{nil}, 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,
|
|
|
|
|
|
|
|
@example
|
|
|
|
(setq scalable-fonts-allowed '("muleindian-2$"))
|
|
|
|
@end example
|
|
|
|
|
|
|
|
@noindent
|
|
|
|
allows the use of scalable fonts with registry @code{muleindian-2}.
|
1999-12-03 19:38:44 +00:00
|
|
|
@end defvar
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
@defun clear-face-cache &optional unload-p
|
|
|
|
@tindex clear-face-cache
|
|
|
|
This function clears the face cache for all frames.
|
|
|
|
If @var{unload-p} is non-@code{nil}, that means to unload
|
|
|
|
all unused fonts as well.
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
@node Face Functions
|
|
|
|
@subsection Functions for Working with Faces
|
|
|
|
|
|
|
|
Here are additional functions for creating and working with faces.
|
|
|
|
|
|
|
|
@defun 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
|
|
|
|
@var{name}.
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
@defun face-list
|
|
|
|
This function returns a list of all defined face names.
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
@defun copy-face old-face new-name &optional frame new-frame
|
|
|
|
This function defines the face @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}.
|
1998-04-20 17:43:57 +00:00
|
|
|
@end defun
|
|
|
|
|
1995-06-06 19:21:15 +00:00
|
|
|
@defun face-id face
|
1998-04-20 17:43:57 +00:00
|
|
|
This function returns the face number of face @var{face}.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end defun
|
|
|
|
|
1998-02-28 01:53:53 +00:00
|
|
|
@defun face-documentation face
|
|
|
|
This function returns the documentation string of face @var{face}, or
|
|
|
|
@code{nil} if none was specified for it.
|
|
|
|
@end defun
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@defun face-equal face1 face2 &optional frame
|
|
|
|
This returns @code{t} if the faces @var{face1} and @var{face2} have the
|
|
|
|
same attributes for display.
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
@defun face-differs-from-default-p face &optional frame
|
|
|
|
This returns @code{t} if the face @var{face} displays differently from
|
1999-10-05 23:26:05 +00:00
|
|
|
the default face. A face is considered to be ``the same'' as the
|
|
|
|
default face if each attribute is either the same as that of the default
|
|
|
|
face, or unspecified (meaning to inherit from the default).
|
1998-05-26 18:56:56 +00:00
|
|
|
@end defun
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@node Auto Faces
|
|
|
|
@subsection Automatic Face Assignment
|
|
|
|
@cindex automatic face assignment
|
|
|
|
@cindex faces, automatic choice
|
|
|
|
|
|
|
|
@cindex Font-Lock mode
|
|
|
|
Starting with Emacs 21, a hook is available for automatically
|
|
|
|
assigning faces to text in the buffer. This hook is used for part of
|
|
|
|
the implementation of Font-Lock mode.
|
|
|
|
|
|
|
|
@tindex fontification-functions
|
|
|
|
@defvar 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
|
|
|
|
@code{face} property. It should also add a non-@code{nil}
|
|
|
|
@code{fontified} 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 non-@code{nil} @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.
|
|
|
|
@end defvar
|
|
|
|
|
|
|
|
@node Font Lookup
|
|
|
|
@subsection Looking Up Fonts
|
|
|
|
|
|
|
|
@defun x-list-fonts pattern &optional face frame maximum
|
|
|
|
This function returns a list of available font names that match
|
|
|
|
@var{pattern}. If the optional arguments @var{face} and @var{frame} are
|
|
|
|
specified, then the list is limited to fonts that are the same size as
|
|
|
|
@var{face} 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
|
|
|
|
@samp{?} 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 non-@code{nil}, 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.
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
These additional functions are available starting in Emacs 21.
|
|
|
|
|
|
|
|
@defun x-family-fonts &optional family frame
|
|
|
|
@tindex x-family-fonts
|
|
|
|
This function returns a list describing the available fonts for family
|
|
|
|
@var{family} 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
|
2001-09-23 18:56:28 +00:00
|
|
|
omitted or @code{nil}, it applies to the selected frame's display
|
|
|
|
(@pxref{Input Focus}).
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
The list contains a vector of the following form for each font:
|
|
|
|
|
|
|
|
@example
|
|
|
|
[@var{family} @var{width} @var{point-size} @var{weight} @var{slant}
|
|
|
|
@var{fixed-p} @var{full} @var{registry-and-encoding}]
|
|
|
|
@end 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.
|
|
|
|
@var{fixed-p} is non-nil if the font is fixed-pitch. @var{full} is the
|
|
|
|
full name of the font, and @var{registry-and-encoding} is a string
|
|
|
|
giving the registry and encoding of the font.
|
|
|
|
|
|
|
|
The result list is sorted according to the current face font sort order.
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
@defun x-font-family-list &optional frame
|
|
|
|
@tindex x-font-family-list
|
|
|
|
This function returns a list of the font families available for
|
|
|
|
@var{frame}'s display. If @var{frame} is omitted or @code{nil}, it
|
2001-09-23 18:56:28 +00:00
|
|
|
describes the selected frame's display (@pxref{Input Focus}).
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
The value is a list of elements of this form:
|
|
|
|
|
|
|
|
@example
|
|
|
|
(@var{family} . @var{fixed-p})
|
|
|
|
@end example
|
|
|
|
|
|
|
|
@noindent
|
|
|
|
Here @var{family} is a font family, and @var{fixed-p} is
|
|
|
|
non-@code{nil} if fonts of that family are fixed-pitch.
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
@defvar font-list-limit
|
|
|
|
@tindex 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.
|
|
|
|
@end defvar
|
|
|
|
|
|
|
|
@node Fontsets
|
|
|
|
@subsection 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.
|
|
|
|
|
|
|
|
@defun 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:
|
|
|
|
|
|
|
|
@smallexample
|
|
|
|
@var{fontpattern}, @r{[}@var{charsetname}:@var{fontname}@r{]@dots{}}
|
|
|
|
@end smallexample
|
|
|
|
|
|
|
|
@noindent
|
|
|
|
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
|
|
|
|
@samp{fontset-@var{alias}}.
|
|
|
|
|
|
|
|
The new fontset has two names, one long and one short. The long name is
|
|
|
|
@var{fontpattern} in its entirety. The short name is
|
|
|
|
@samp{fontset-@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 non-@code{nil}, in which case this
|
|
|
|
function does nothing.
|
|
|
|
|
|
|
|
If optional argument @var{style-variant-p} is non-@code{nil}, 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.
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
The construct @samp{@var{charset}:@var{font}} specifies which font to
|
|
|
|
use (in this fontset) for one particular character set. Here,
|
|
|
|
@var{charset} 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
|
|
|
|
@samp{fontset-@var{alias}} with a value that names one character set.
|
|
|
|
For the @sc{ascii} character set, @samp{fontset-@var{alias}} 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,
|
|
|
|
|
|
|
|
@example
|
|
|
|
-*-fixed-medium-r-normal-*-24-*-*-*-*-*-fontset-24
|
|
|
|
@end example
|
|
|
|
|
|
|
|
@noindent
|
2000-01-20 18:18:58 +00:00
|
|
|
the font specification for @sc{ascii} characters would be this:
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
@example
|
|
|
|
-*-fixed-medium-r-normal-*-24-*-ISO8859-1
|
|
|
|
@end example
|
|
|
|
|
|
|
|
@noindent
|
|
|
|
and the font specification for Chinese GB2312 characters would be this:
|
|
|
|
|
|
|
|
@example
|
|
|
|
-*-fixed-medium-r-normal-*-24-*-gb2312*-*
|
|
|
|
@end 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, @samp{Fontset-@var{n}} can be specified as below:
|
|
|
|
|
|
|
|
@smallexample
|
|
|
|
Emacs.Fontset-0: -*-fixed-medium-r-normal-*-24-*-*-*-*-*-fontset-24,\
|
|
|
|
chinese-gb2312:-*-*-medium-r-normal-*-24-*-gb2312*-*
|
|
|
|
@end smallexample
|
|
|
|
|
|
|
|
@noindent
|
|
|
|
Then, the font specifications for all but Chinese GB2312 characters have
|
|
|
|
@samp{fixed} in the @var{family} field, and the font specification for
|
|
|
|
Chinese GB2312 characters has a wild card @samp{*} in the @var{family}
|
|
|
|
field.
|
|
|
|
|
|
|
|
@node Display Property
|
|
|
|
@section The @code{display} Property
|
|
|
|
@cindex display specification
|
|
|
|
@kindex display @r{(text property)}
|
|
|
|
|
1999-10-05 23:26:05 +00:00
|
|
|
The @code{display} text property (or overlay property) is used to
|
|
|
|
insert images into text, and also control other aspects of how text
|
|
|
|
displays. These features are available starting in Emacs 21. The value
|
|
|
|
of the @code{display} property should be a display specification, or a
|
|
|
|
list or vector containing several display specifications. The rest of
|
|
|
|
this section describes several kinds of display specifications and what
|
|
|
|
they mean.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
@menu
|
1999-10-05 23:26:05 +00:00
|
|
|
* Specified Space:: Displaying one space with a specified width.
|
|
|
|
* 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.
|
|
|
|
* Conditional Display:: Making any of the above features conditional
|
|
|
|
depending on some Lisp expression.
|
1999-09-17 06:59:04 +00:00
|
|
|
@end menu
|
|
|
|
|
|
|
|
@node Specified Space
|
|
|
|
@subsection Specified Spaces
|
|
|
|
@cindex spaces, specified height or width
|
|
|
|
@cindex specified spaces
|
|
|
|
@cindex variable-width spaces
|
|
|
|
|
|
|
|
To display a space of specified width and/or height, use a display
|
1999-10-05 23:26:05 +00:00
|
|
|
specification of the form @code{(space . @var{props})}, where
|
|
|
|
@var{props} 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
|
2002-04-01 03:54:12 +00:00
|
|
|
can use in @var{props} to specify the weight of the space:
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
@table @code
|
|
|
|
@item :width @var{width}
|
|
|
|
Specifies that the space width should be @var{width} times the normal
|
|
|
|
character width. @var{width} can be an integer or floating point
|
|
|
|
number.
|
|
|
|
|
|
|
|
@item :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}.
|
|
|
|
|
|
|
|
@item :align-to @var{hpos}
|
|
|
|
Specifies that the space should be wide enough to reach @var{hpos}. The
|
1999-10-05 23:26:05 +00:00
|
|
|
value @var{hpos} is measured in units of the normal character width. It
|
|
|
|
may be an interer or a floating point number.
|
1999-09-17 06:59:04 +00:00
|
|
|
@end table
|
|
|
|
|
2002-04-01 03:54:12 +00:00
|
|
|
You should use one and only one of the above properties. You can
|
|
|
|
also specify the height of the space, with other properties:
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
@table @code
|
|
|
|
@item :height @var{height}
|
|
|
|
Specifies the height of the space, as @var{height},
|
|
|
|
measured in terms of the normal line height.
|
|
|
|
|
|
|
|
@item :relative-height @var{factor}
|
|
|
|
Specifies the height of the space, multiplying the ordinary height
|
|
|
|
of the text having this display specification by @var{factor}.
|
|
|
|
|
|
|
|
@item :ascent @var{ascent}
|
|
|
|
Specifies that @var{ascent} percent of the height of the space should be
|
1999-10-05 23:26:05 +00:00
|
|
|
considered as the ascent of the space---that is, the part above the
|
|
|
|
baseline. The value of @var{ascent} must be a non-negative number no
|
|
|
|
greater than 100.
|
1999-09-17 06:59:04 +00:00
|
|
|
@end table
|
|
|
|
|
2002-04-01 03:54:12 +00:00
|
|
|
Don't use both @code{:height} and @code{:relative-height} together.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
@node Other Display Specs
|
|
|
|
@subsection Other Display Specifications
|
|
|
|
|
|
|
|
@table @code
|
|
|
|
@item (image . @var{image-props})
|
|
|
|
This is in fact 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.
|
|
|
|
|
2000-10-13 18:05:11 +00:00
|
|
|
@item ((margin nil) @var{string})
|
|
|
|
@itemx @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. This is a special case of marginal display
|
|
|
|
(@pxref{Display Margins}).
|
|
|
|
|
2002-04-01 03:54:12 +00:00
|
|
|
Recursive display specifications are not supported---string display
|
|
|
|
specifications must not have @code{display} properties themselves.
|
2001-03-22 15:16:31 +00:00
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@item (space-width @var{factor})
|
1999-10-05 23:26:05 +00:00
|
|
|
This display specification affects all the space characters within the
|
|
|
|
text that has the specification. It displays all of these spaces
|
|
|
|
@var{factor} 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.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
@item (height @var{height})
|
|
|
|
This display specification makes the text taller or shorter.
|
|
|
|
Here are the possibilities for @var{height}:
|
|
|
|
|
|
|
|
@table @asis
|
|
|
|
@item @code{(+ @var{n})}
|
|
|
|
This means to use a font that is @var{n} steps larger. A ``step'' is
|
1999-10-05 23:26:05 +00:00
|
|
|
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.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
@item @code{(- @var{n})}
|
|
|
|
This means to use a font that is @var{n} steps smaller.
|
|
|
|
|
|
|
|
@item a number, @var{factor}
|
|
|
|
A number, @var{factor}, means to use a font that is @var{factor} times
|
|
|
|
as tall as the default font.
|
|
|
|
|
|
|
|
@item 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.
|
|
|
|
|
|
|
|
@item 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
|
|
|
|
@code{height} bound to the current specified font height.
|
|
|
|
@end table
|
|
|
|
|
|
|
|
@item (raise @var{factor})
|
|
|
|
This kind of display specification raises or lowers the text
|
|
|
|
it applies to, relative to the baseline of the line.
|
|
|
|
|
|
|
|
@var{factor} 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.
|
|
|
|
@end table
|
|
|
|
|
|
|
|
@node Display Margins
|
|
|
|
@subsection Displaying in the Margins
|
|
|
|
@cindex display margins
|
|
|
|
@cindex 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
|
|
|
|
@code{(margin left-margin)} on it. To put an image in a display margin,
|
|
|
|
use that display specification along with the display specification for
|
2002-01-02 05:28:50 +00:00
|
|
|
the image. Unfortunately, there is currently no way to make
|
|
|
|
text or images in the margin mouse-sensitive.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
2001-12-24 16:29:42 +00:00
|
|
|
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.
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
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:
|
|
|
|
|
|
|
|
@defvar left-margin-width
|
|
|
|
@tindex left-margin-width
|
|
|
|
This variable specifies the width of the left margin.
|
|
|
|
It is buffer-local in all buffers.
|
|
|
|
@end defvar
|
|
|
|
|
|
|
|
@defvar right-margin-width
|
|
|
|
@tindex right-margin-width
|
|
|
|
This variable specifies the width of the right margin.
|
|
|
|
It is buffer-local in all buffers.
|
|
|
|
@end 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
|
|
|
|
@code{set-window-buffer}.
|
|
|
|
|
|
|
|
You can also set the margin widths immediately.
|
|
|
|
|
2001-03-22 15:16:31 +00:00
|
|
|
@defun set-window-margins window left &optional right
|
1999-09-17 06:59:04 +00:00
|
|
|
@tindex set-window-margins
|
|
|
|
This function specifies the margin widths for window @var{window}.
|
|
|
|
The argument @var{left} controls the left margin and
|
2001-03-22 15:16:31 +00:00
|
|
|
@var{right} controls the right margin (default @code{0}).
|
1999-09-17 06:59:04 +00:00
|
|
|
@end defun
|
|
|
|
|
|
|
|
@defun window-margins &optional window
|
|
|
|
@tindex window-margins
|
|
|
|
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.
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
@node Conditional Display
|
|
|
|
@subsection Conditional Display Specifications
|
|
|
|
@cindex conditional display specifications
|
|
|
|
|
|
|
|
You can make any display specification conditional. To do that,
|
2000-06-06 14:56:30 +00:00
|
|
|
package it in another list of the form @code{(when @var{condition} .
|
1999-09-17 06:59:04 +00:00
|
|
|
@var{spec})}. Then the specification @var{spec} applies only when
|
|
|
|
@var{condition} evaluates to a non-@code{nil} value. During the
|
2001-08-30 12:13:54 +00:00
|
|
|
evaluation, @code{object} is bound to the string or buffer having the
|
|
|
|
conditional @code{display} property. @code{position} and
|
|
|
|
@code{buffer-position} 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.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
@node Images
|
|
|
|
@section Images
|
|
|
|
@cindex 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}). Like the
|
|
|
|
@code{display} property, this feature is available starting in Emacs 21.
|
|
|
|
|
|
|
|
Emacs can display a number of different image formats; some of them
|
|
|
|
are supported only if particular support libraries are installed on your
|
|
|
|
machine. The supported image formats include XBM, XPM (needing the
|
|
|
|
libraries @code{libXpm} version 3.4k and @code{libz}), GIF (needing
|
|
|
|
@code{libungif} 4.1.0), Postscript, PBM, JPEG (needing the
|
|
|
|
@code{libjpeg} library version v6a), TIFF (needing @code{libtiff} v3.4),
|
|
|
|
and PNG (needing @code{libpng} 1.0.2).
|
|
|
|
|
|
|
|
You specify one of these formats with an image type symbol. The image
|
|
|
|
type symbols are @code{xbm}, @code{xpm}, @code{gif}, @code{postscript},
|
|
|
|
@code{pbm}, @code{jpeg}, @code{tiff}, and @code{png}.
|
|
|
|
|
|
|
|
@defvar image-types
|
|
|
|
This variable contains a list of those image type symbols that are
|
|
|
|
supported in the current configuration.
|
|
|
|
@end defvar
|
|
|
|
|
|
|
|
@menu
|
1999-10-05 23:26:05 +00:00
|
|
|
* 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.
|
1999-09-17 06:59:04 +00:00
|
|
|
@end menu
|
|
|
|
|
|
|
|
@node Image Descriptors
|
|
|
|
@subsection Image Descriptors
|
|
|
|
@cindex 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
|
1999-11-10 22:01:35 +00:00
|
|
|
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
|
|
|
|
@var{type}} 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.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
Here is a list of other properties that are meaningful for all image
|
|
|
|
types:
|
|
|
|
|
|
|
|
@table @code
|
2001-03-12 03:45:12 +00:00
|
|
|
@item :file @var{file}
|
|
|
|
The @code{:file} property specifies to load the image from file
|
|
|
|
@var{file}. If @var{file} is not an absolute file name, it is expanded
|
|
|
|
in @code{data-directory}.
|
|
|
|
|
|
|
|
@item :data @var{data}
|
|
|
|
The @code{:data} property specifies 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,
|
|
|
|
@code{: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}.
|
|
|
|
|
|
|
|
@item :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 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.
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@item :ascent @var{ascent}
|
2000-05-24 13:10:23 +00:00
|
|
|
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.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
@item :relief @var{relief}
|
|
|
|
The @code{:relief} property, if non-@code{nil}, 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.
|
|
|
|
|
2001-01-17 14:11:43 +00:00
|
|
|
@item :conversion @var{algorithm}
|
|
|
|
The @code{:conversion} property, if non-@code{nil}, specifies a
|
1999-09-17 06:59:04 +00:00
|
|
|
conversion algorithm that should be applied to the image before it is
|
|
|
|
displayed; the value, @var{algorithm}, specifies which algorithm.
|
|
|
|
|
2000-11-29 14:53:29 +00:00
|
|
|
@table @code
|
|
|
|
@item laplace
|
|
|
|
@itemx 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.
|
|
|
|
|
|
|
|
@item (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:
|
|
|
|
@iftex
|
|
|
|
@tex
|
|
|
|
$$\pmatrix{x-1/y-1 & x/y-1 & x+1/y-1 \cr
|
|
|
|
x-1/y & x/y & x+1/y \cr
|
|
|
|
x-1/y+1& x/y+1 & x+1/y+1 \cr}$$
|
|
|
|
@end tex
|
|
|
|
@end iftex
|
|
|
|
@ifnottex
|
|
|
|
@display
|
|
|
|
(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)
|
|
|
|
@end display
|
|
|
|
@end 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
|
|
|
|
@iftex
|
|
|
|
@tex
|
|
|
|
$$\pmatrix{1 & 0 & 0 \cr
|
|
|
|
0& 0 & 0 \cr
|
|
|
|
9 & 9 & -1 \cr}$$
|
|
|
|
@end tex
|
|
|
|
@end iftex
|
|
|
|
@ifnottex
|
|
|
|
@display
|
|
|
|
(1 0 0
|
|
|
|
0 0 0
|
|
|
|
9 9 -1)
|
|
|
|
@end display
|
|
|
|
@end ifnottex
|
|
|
|
|
|
|
|
Emboss edge-detection uses a matrix of
|
|
|
|
@iftex
|
|
|
|
@tex
|
|
|
|
$$\pmatrix{ 2 & -1 & 0 \cr
|
|
|
|
-1 & 0 & 1 \cr
|
|
|
|
0 & 1 & -2 \cr}$$
|
|
|
|
@end tex
|
|
|
|
@end iftex
|
|
|
|
@ifnottex
|
|
|
|
@display
|
|
|
|
( 2 -1 0
|
|
|
|
-1 0 1
|
|
|
|
0 1 -2)
|
|
|
|
@end display
|
|
|
|
@end ifnottex
|
|
|
|
|
|
|
|
@item disabled
|
|
|
|
Specifies transforming the image so that it looks ``disabled''.
|
|
|
|
@end table
|
1999-09-17 06:59:04 +00:00
|
|
|
|
2000-11-29 14:53:29 +00:00
|
|
|
@item :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,
|
|
|
|
@var{bg} must be a list @code{(@var{red} @var{green} @var{blue})}
|
|
|
|
specifying the color to assume for the background of the image.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
2000-11-29 14:53:29 +00:00
|
|
|
If @var{mask} is 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}.
|
1999-09-17 06:59:04 +00:00
|
|
|
@end table
|
|
|
|
|
2000-11-29 14:53:29 +00:00
|
|
|
@defun image-mask-p spec &optional frame
|
|
|
|
@tindex image-mask-p
|
|
|
|
This function returns @code{t} if image @var{spec} has a mask bitmap.
|
|
|
|
@var{frame} is the frame on which the image will be displayed.
|
2001-09-23 18:56:28 +00:00
|
|
|
@var{frame} @code{nil} or omitted means to use the selected frame
|
|
|
|
(@pxref{Input Focus}).
|
2000-11-29 14:53:29 +00:00
|
|
|
@end defun
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@node XBM Images
|
|
|
|
@subsection XBM Images
|
|
|
|
@cindex 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:
|
|
|
|
|
|
|
|
@table @code
|
|
|
|
@item :foreground @var{foreground}
|
|
|
|
The value, @var{foreground}, should be a string specifying the image
|
2001-05-30 15:32:04 +00:00
|
|
|
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.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
@item :background @var{background}
|
|
|
|
The value, @var{background}, should be a string specifying the image
|
2001-05-30 15:32:04 +00:00
|
|
|
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.
|
1999-09-17 06:59:04 +00:00
|
|
|
@end table
|
|
|
|
|
2000-01-03 00:19:17 +00:00
|
|
|
If you specify an XBM image using data within Emacs instead of an
|
2000-05-03 10:45:51 +00:00
|
|
|
external file, use the following three properties:
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
@table @code
|
2000-05-03 10:45:51 +00:00
|
|
|
@item :data @var{data}
|
|
|
|
The value, @var{data}, specifies the contents of the image.
|
|
|
|
There are three formats you can use for @var{data}:
|
1999-09-17 06:59:04 +00:00
|
|
|
|
2000-05-03 10:45:51 +00:00
|
|
|
@itemize @bullet
|
|
|
|
@item
|
|
|
|
A vector of strings or bool-vectors, each specifying one line of the
|
|
|
|
image. Do specify @code{:height} and @code{:width}.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
2000-05-03 10:45:51 +00:00
|
|
|
@item
|
|
|
|
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.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
2000-05-03 10:45:51 +00:00
|
|
|
@item
|
|
|
|
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
|
|
|
|
@code{: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.
|
|
|
|
@end itemize
|
|
|
|
|
|
|
|
@item :width @var{width}
|
|
|
|
The value, @var{width}, specifies the width of the image, in pixels.
|
|
|
|
|
|
|
|
@item :height @var{height}
|
|
|
|
The value, @var{height}, specifies the height of the image, in pixels.
|
1999-09-17 06:59:04 +00:00
|
|
|
@end table
|
|
|
|
|
|
|
|
@node XPM Images
|
|
|
|
@subsection XPM Images
|
|
|
|
@cindex XPM
|
|
|
|
|
2000-01-03 00:19:17 +00:00
|
|
|
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:
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
@table @code
|
|
|
|
@item :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.
|
|
|
|
@end table
|
|
|
|
|
|
|
|
@node GIF Images
|
|
|
|
@subsection GIF Images
|
|
|
|
@cindex GIF
|
|
|
|
|
|
|
|
For GIF images, specify image type @code{gif}. Because of the patents
|
|
|
|
in the US covering the LZW algorithm, the continued use of GIF format is
|
|
|
|
a problem for the whole Internet; to end this problem, it is a good idea
|
|
|
|
for everyone, even outside the US, to stop using GIFS right away
|
|
|
|
(@uref{http://www.burnallgifs.org/}). But if you still want to use
|
|
|
|
them, Emacs can display them.
|
|
|
|
|
|
|
|
@table @code
|
|
|
|
@item :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. An error is signaled if the GIF file
|
|
|
|
doesn't contain an image with index @var{index}.
|
|
|
|
@end table
|
|
|
|
|
|
|
|
@ignore
|
|
|
|
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)))
|
|
|
|
@end ignore
|
|
|
|
|
|
|
|
@node Postscript Images
|
|
|
|
@subsection Postscript Images
|
|
|
|
@cindex 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:
|
|
|
|
|
|
|
|
@table @code
|
|
|
|
@item :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.
|
|
|
|
|
|
|
|
@item :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.
|
|
|
|
|
|
|
|
@item :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
|
|
|
|
@samp{BoundingBox} comment found in Postscript files.
|
|
|
|
|
|
|
|
@example
|
|
|
|
%%BoundingBox: 22 171 567 738
|
|
|
|
@end example
|
|
|
|
@end table
|
|
|
|
|
2000-01-03 00:19:17 +00:00
|
|
|
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.
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@node Other Image Types
|
|
|
|
@subsection Other Image Types
|
|
|
|
@cindex PBM
|
|
|
|
|
|
|
|
For PBM images, specify image type @code{pbm}. Color, gray-scale and
|
2000-10-16 20:11:41 +00:00
|
|
|
monochromatic images are supported. For mono PBM images, two additional
|
|
|
|
image properties are supported.
|
|
|
|
|
|
|
|
@table @code
|
|
|
|
@item :foreground @var{foreground}
|
|
|
|
The value, @var{foreground}, should be a string specifying the image
|
2001-05-30 15:32:04 +00:00
|
|
|
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.
|
2000-10-16 20:11:41 +00:00
|
|
|
|
|
|
|
@item :background @var{background}
|
|
|
|
The value, @var{background}, should be a string specifying the image
|
2001-05-30 15:32:04 +00:00
|
|
|
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.
|
2000-10-16 20:11:41 +00:00
|
|
|
@end table
|
1999-09-17 06:59:04 +00:00
|
|
|
|
2000-01-03 00:19:17 +00:00
|
|
|
For JPEG images, specify image type @code{jpeg}.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
For TIFF images, specify image type @code{tiff}.
|
|
|
|
|
|
|
|
For PNG images, specify image type @code{png}.
|
|
|
|
|
|
|
|
@node Defining Images
|
|
|
|
@subsection Defining Images
|
|
|
|
|
2000-09-04 13:57:47 +00:00
|
|
|
The functions @code{create-image}, @code{defimage} and
|
|
|
|
@code{find-image} provide convenient ways to create image descriptors.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
@defun create-image file &optional type &rest props
|
|
|
|
@tindex create-image
|
|
|
|
This function creates and returns an image descriptor which uses the
|
|
|
|
data in @var{file}.
|
|
|
|
|
|
|
|
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,
|
|
|
|
|
|
|
|
@example
|
|
|
|
(create-image "foo.xpm" 'xpm :heuristic-mask t)
|
|
|
|
@end example
|
|
|
|
|
|
|
|
The function returns @code{nil} if images of this type are not
|
|
|
|
supported. Otherwise it returns an image descriptor.
|
|
|
|
@end defun
|
|
|
|
|
2001-11-14 19:31:18 +00:00
|
|
|
@defmac defimage symbol specs &optional doc
|
1999-09-17 06:59:04 +00:00
|
|
|
@tindex defimage
|
2001-11-14 19:31:18 +00:00
|
|
|
This macro defines @var{symbol} as an image name. The arguments
|
|
|
|
@var{specs} is a list which specifies how to display the image.
|
|
|
|
The third argument, @var{doc}, is an optional documentation string.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
Each argument in @var{specs} has the form of a property list, and each
|
2001-11-14 19:31:18 +00:00
|
|
|
one should specify at least the @code{:type} property and either the
|
|
|
|
@code{:file} or the @code{:data} property. The value of @code{:type}
|
|
|
|
should be a symbol specifying the image type, the value of
|
|
|
|
@code{:file} is the file to load the image from, and the value of
|
|
|
|
@code{:data} is a string containing the actual image data. Here is an
|
|
|
|
example:
|
1999-09-17 06:59:04 +00:00
|
|
|
|
1999-10-05 23:26:05 +00:00
|
|
|
@example
|
|
|
|
(defimage test-image
|
2002-07-12 23:30:17 +00:00
|
|
|
((:type xpm :file "~/test1.xpm")
|
|
|
|
(:type xbm :file "~/test1.xbm")))
|
1999-10-05 23:26:05 +00:00
|
|
|
@end example
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
@code{defimage} 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
|
2001-11-14 19:31:18 +00:00
|
|
|
stored in @var{symbol}.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
2001-11-14 19:31:18 +00:00
|
|
|
If none of the alternatives will work, then @var{symbol} is defined
|
1999-09-17 06:59:04 +00:00
|
|
|
as @code{nil}.
|
|
|
|
@end defmac
|
|
|
|
|
2000-09-04 13:57:47 +00:00
|
|
|
@defun find-image specs
|
|
|
|
@tindex find-image
|
|
|
|
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 @w{@code{:file @var{file}}}
|
|
|
|
or @w{@code{: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
|
|
|
|
@var{file} 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 first on @code{load-path} and then in
|
|
|
|
@code{data-directory}.
|
|
|
|
@end defun
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@node Showing Images
|
|
|
|
@subsection 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.
|
|
|
|
|
2000-06-06 14:56:30 +00:00
|
|
|
@defun insert-image image &optional string area
|
1999-09-17 06:59:04 +00:00
|
|
|
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
|
1999-10-05 23:26:05 +00:00
|
|
|
@code{defimage}. The argument @var{string} specifies the text to put in
|
|
|
|
the buffer to hold the image.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
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;
|
|
|
|
@code{right-margin} specifies the right margin. If @var{area} is
|
|
|
|
@code{nil} or omitted, the image is displayed at point within the
|
|
|
|
buffer's text.
|
|
|
|
|
1999-10-05 23:26:05 +00:00
|
|
|
Internally, this function inserts @var{string} in the buffer, and gives
|
|
|
|
it a @code{display} property which specifies @var{image}. @xref{Display
|
1999-09-17 06:59:04 +00:00
|
|
|
Property}.
|
|
|
|
@end defun
|
|
|
|
|
2000-06-06 14:56:30 +00:00
|
|
|
@defun put-image image pos &optional string area
|
1999-09-17 06:59:04 +00:00
|
|
|
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.
|
2000-06-06 14:56:30 +00:00
|
|
|
The argument @var{string} specifies the text that should hold the image
|
|
|
|
as an alternative to the default.
|
1999-09-17 06:59:04 +00:00
|
|
|
|
|
|
|
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;
|
|
|
|
@code{right-margin} specifies the right margin. If @var{area} is
|
|
|
|
@code{nil} or omitted, the image is displayed at point within the
|
|
|
|
buffer's text.
|
|
|
|
|
|
|
|
Internally, this function creates an overlay, and gives it a
|
|
|
|
@code{before-string} property containing text that has a @code{display}
|
|
|
|
property whose value is the image. (Whew!)
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
@defun remove-images start end &optional buffer
|
|
|
|
This function removes images in @var{buffer} between positions
|
|
|
|
@var{start} and @var{end}. If @var{buffer} is omitted or @code{nil},
|
|
|
|
images are removed from the current buffer.
|
|
|
|
|
2000-01-16 00:29:04 +00:00
|
|
|
This removes only images that were put into @var{buffer} the way
|
1999-09-17 06:59:04 +00:00
|
|
|
@code{put-image} does it, not images that were inserted with
|
|
|
|
@code{insert-image} or in other ways.
|
|
|
|
@end defun
|
|
|
|
|
2000-09-04 13:57:47 +00:00
|
|
|
@defun image-size spec &optional pixels frame
|
|
|
|
@tindex image-size
|
|
|
|
This function returns the size of an image as a pair
|
|
|
|
@w{@code{(@var{width} . @var{height})}}. @var{spec} is an image
|
|
|
|
specification. @var{pixels} non-nil 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.
|
2001-09-23 18:56:28 +00:00
|
|
|
@var{frame} null or omitted means use the selected frame (@pxref{Input
|
|
|
|
Focus}).
|
2000-09-04 13:57:47 +00:00
|
|
|
@end defun
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@node Image Cache
|
|
|
|
@subsection Image Cache
|
|
|
|
|
|
|
|
Emacs stores images in an image cache when it displays them, so it can
|
|
|
|
display them again more efficiently. It removes an image from the cache
|
|
|
|
when it hasn't been displayed for a specified period of time.
|
|
|
|
|
2000-05-02 10:39:45 +00:00
|
|
|
When an image is looked up in the cache, its specification is compared
|
|
|
|
with cached image specifications using @code{equal}. This means that
|
|
|
|
all images with equal specifications share the same image in the cache.
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@defvar image-cache-eviction-delay
|
|
|
|
@tindex 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.
|
|
|
|
@end defvar
|
|
|
|
|
|
|
|
@defun clear-image-cache &optional frame
|
|
|
|
@tindex clear-image-cache
|
|
|
|
This function clears the image cache. If @var{frame} is non-@code{nil},
|
|
|
|
only the cache for that frame is cleared. Otherwise all frames' caches
|
|
|
|
are cleared.
|
|
|
|
@end defun
|
2000-01-26 23:57:05 +00:00
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@node Blinking
|
|
|
|
@section Blinking Parentheses
|
|
|
|
@cindex parenthesis matching
|
|
|
|
@cindex blinking
|
|
|
|
@cindex balancing parentheses
|
|
|
|
@cindex close parenthesis
|
|
|
|
|
|
|
|
This section describes the mechanism by which Emacs shows a matching
|
|
|
|
open parenthesis when the user inserts a close parenthesis.
|
|
|
|
|
|
|
|
@defvar 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.
|
|
|
|
@end defvar
|
|
|
|
|
1998-05-26 18:56:56 +00:00
|
|
|
@defopt blink-matching-paren
|
1994-03-30 18:36:47 +00:00
|
|
|
If this variable is @code{nil}, then @code{blink-matching-open} does
|
|
|
|
nothing.
|
1998-05-26 18:56:56 +00:00
|
|
|
@end defopt
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1998-05-26 18:56:56 +00:00
|
|
|
@defopt blink-matching-paren-distance
|
1994-03-30 18:36:47 +00:00
|
|
|
This variable specifies the maximum distance to scan for a matching
|
|
|
|
parenthesis before giving up.
|
1998-05-26 18:56:56 +00:00
|
|
|
@end defopt
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1998-05-26 18:56:56 +00:00
|
|
|
@defopt blink-matching-delay
|
1995-06-06 19:21:15 +00:00
|
|
|
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.
|
1998-05-26 18:56:56 +00:00
|
|
|
@end defopt
|
1995-06-06 19:21:15 +00:00
|
|
|
|
1998-05-26 18:56:56 +00:00
|
|
|
@deffn Command blink-matching-open
|
1994-03-30 18:36:47 +00:00
|
|
|
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.
|
|
|
|
|
|
|
|
@smallexample
|
|
|
|
@group
|
|
|
|
(defun interactive-blink-matching-open ()
|
|
|
|
@c Do not break this line! -- rms.
|
|
|
|
@c The first line of a doc string
|
|
|
|
@c must stand alone.
|
|
|
|
"Indicate momentarily the start of sexp before point."
|
|
|
|
(interactive)
|
|
|
|
@end group
|
|
|
|
@group
|
|
|
|
(let ((blink-matching-paren-distance
|
|
|
|
(buffer-size))
|
|
|
|
(blink-matching-paren t))
|
|
|
|
(blink-matching-open)))
|
|
|
|
@end group
|
|
|
|
@end smallexample
|
1998-05-26 18:56:56 +00:00
|
|
|
@end deffn
|
1994-03-30 18:36:47 +00:00
|
|
|
|
|
|
|
@node Inverse Video
|
|
|
|
@section Inverse Video
|
|
|
|
@cindex Inverse Video
|
|
|
|
|
|
|
|
@defopt inverse-video
|
|
|
|
@cindex highlighting
|
|
|
|
This variable controls whether Emacs uses inverse video for all text
|
|
|
|
on the screen. Non-@code{nil} means yes, @code{nil} means no. The
|
|
|
|
default is @code{nil}.
|
|
|
|
@end defopt
|
|
|
|
|
|
|
|
@defopt mode-line-inverse-video
|
1999-10-05 23:26:05 +00:00
|
|
|
This variable controls the use of inverse video for mode lines and menu
|
|
|
|
bars. If it is non-@code{nil}, then these lines are displayed in
|
2000-01-16 00:29:04 +00:00
|
|
|
inverse video. Otherwise, these lines are displayed normally, just like
|
1999-10-05 23:26:05 +00:00
|
|
|
other text. The default is @code{t}.
|
|
|
|
|
|
|
|
For window frames, this feature actually applies the face named
|
|
|
|
@code{mode-line}; that face is normally set up as the inverse of the
|
|
|
|
default face, unless you change it.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end defopt
|
|
|
|
|
|
|
|
@node Usual Display
|
|
|
|
@section 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:
|
|
|
|
|
|
|
|
@itemize @bullet
|
|
|
|
@item
|
|
|
|
Character codes 32 through 126 map to glyph codes 32 through 126.
|
|
|
|
Normally this means they display as themselves.
|
|
|
|
|
|
|
|
@item
|
|
|
|
Character code 9 is a horizontal tab. It displays as whitespace
|
|
|
|
up to a position determined by @code{tab-width}.
|
|
|
|
|
|
|
|
@item
|
|
|
|
Character code 10 is a newline.
|
|
|
|
|
|
|
|
@item
|
|
|
|
All other codes in the range 0 through 31, and code 127, display in one
|
1994-09-22 22:00:06 +00:00
|
|
|
of two ways according to the value of @code{ctl-arrow}. If it is
|
1994-03-30 18:36:47 +00:00
|
|
|
non-@code{nil}, these codes map to sequences of two glyphs, where the
|
1999-09-17 06:59:04 +00:00
|
|
|
first glyph is the @sc{ascii} code for @samp{^}. (A display table can
|
1994-03-30 18:36:47 +00:00
|
|
|
specify a glyph to use instead of @samp{^}.) Otherwise, these codes map
|
|
|
|
just like the codes in the range 128 to 255.
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
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 non-@sc{ascii} characters
|
|
|
|
that the MS-DOS terminal doesn't support. @xref{MS-DOS and MULE,,,
|
|
|
|
emacs, The GNU Emacs Manual}.
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@item
|
|
|
|
Character codes 128 through 255 map to sequences of four glyphs, where
|
1999-09-17 06:59:04 +00:00
|
|
|
the first glyph is the @sc{ascii} code for @samp{\}, and the others are
|
1998-05-19 03:45:57 +00:00
|
|
|
digit characters representing the character code in octal. (A display
|
1998-04-20 17:43:57 +00:00
|
|
|
table can specify a glyph to use instead of @samp{\}.)
|
|
|
|
|
|
|
|
@item
|
|
|
|
Multibyte character codes above 256 are displayed as themselves, or as a
|
|
|
|
question mark or empty box if the terminal cannot display that
|
|
|
|
character.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end itemize
|
|
|
|
|
|
|
|
The usual display conventions apply even when there is a display
|
|
|
|
table, for any character whose entry in the active display table is
|
|
|
|
@code{nil}. Thus, when you set up a display table, you need only
|
1998-04-20 17:43:57 +00:00
|
|
|
specify the characters for which you want special behavior.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1999-07-17 02:15:13 +00:00
|
|
|
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
|
1999-08-30 18:58:31 +00:00
|
|
|
conversion (@pxref{Coding System Basics}).
|
1999-07-17 02:15:13 +00:00
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
These variables affect the way certain characters are displayed on the
|
|
|
|
screen. Since they change the number of columns the characters occupy,
|
1998-02-28 01:53:53 +00:00
|
|
|
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
|
|
|
|
@code{force-mode-line-update} (@pxref{Mode Line Format}).
|
1994-03-30 18:36:47 +00:00
|
|
|
|
|
|
|
@defopt ctl-arrow
|
|
|
|
@cindex control characters in display
|
|
|
|
This buffer-local variable controls how control characters are
|
|
|
|
displayed. If it is non-@code{nil}, 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}.
|
|
|
|
@end defopt
|
|
|
|
|
|
|
|
@c Following may have overfull hbox.
|
|
|
|
@defvar 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}.
|
|
|
|
@end defvar
|
|
|
|
|
1999-12-03 19:11:12 +00:00
|
|
|
@defopt indicate-empty-lines
|
|
|
|
@tindex indicate-empty-lines
|
2002-01-22 11:39:38 +00:00
|
|
|
@cindex fringes, and empty line indication
|
1999-12-03 19:11:12 +00:00
|
|
|
When this is non-@code{nil}, Emacs displays a special glyph in
|
|
|
|
each empty line at the end of the buffer, on terminals that
|
|
|
|
support it (window systems).
|
|
|
|
@end defopt
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@defopt tab-width
|
|
|
|
The value of this variable is the spacing between tab stops used for
|
1999-10-05 23:26:05 +00:00
|
|
|
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}.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end defopt
|
|
|
|
|
|
|
|
@node Display Tables
|
|
|
|
@section Display Tables
|
|
|
|
|
|
|
|
@cindex display table
|
1998-04-20 17:43:57 +00:00
|
|
|
You can use the @dfn{display table} feature to control how all possible
|
|
|
|
character codes display on the screen. This is useful for displaying
|
1999-09-17 06:59:04 +00:00
|
|
|
European languages that have letters not in the @sc{ascii} character
|
1998-04-20 17:43:57 +00:00
|
|
|
set.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
|
|
|
The display table maps each character code into a sequence of
|
1999-09-17 06:59:04 +00:00
|
|
|
@dfn{glyphs}, each glyph being a graphic that takes up one character
|
1994-03-30 18:36:47 +00:00
|
|
|
position on the screen. You can also define how to display each glyph
|
|
|
|
on your terminal, using the @dfn{glyph table}.
|
|
|
|
|
1998-02-28 01:53:53 +00:00
|
|
|
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
|
|
|
|
@code{force-mode-line-update} (@pxref{Mode Line Format}).
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@menu
|
|
|
|
* 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.
|
|
|
|
@end menu
|
|
|
|
|
|
|
|
@node Display Table Format
|
|
|
|
@subsection Display Table Format
|
|
|
|
|
1998-05-19 03:45:57 +00:00
|
|
|
A display table is actually a char-table (@pxref{Char-Tables}) with
|
|
|
|
@code{display-table} as its subtype.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
|
|
|
@defun make-display-table
|
|
|
|
This creates and returns a display table. The table initially has
|
|
|
|
@code{nil} in all elements.
|
|
|
|
@end defun
|
|
|
|
|
1998-02-28 01:53:53 +00:00
|
|
|
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 glyph
|
|
|
|
values (@pxref{Glyphs}). If an element is @code{nil}, it says to
|
|
|
|
display that character according to the usual display conventions
|
|
|
|
(@pxref{Usual Display}).
|
1995-06-05 12:23:13 +00:00
|
|
|
|
|
|
|
If you use the display table to change the display of newline
|
|
|
|
characters, the whole buffer will be displayed as one long ``line.''
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1998-02-28 01:53:53 +00:00
|
|
|
The display table also has six ``extra slots'' which serve special
|
1998-04-20 17:43:57 +00:00
|
|
|
purposes. Here is a table of their meanings; @code{nil} in any slot
|
|
|
|
means to use the default for that slot, as stated below.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
|
|
|
@table @asis
|
1998-02-28 01:53:53 +00:00
|
|
|
@item 0
|
1994-03-30 18:36:47 +00:00
|
|
|
The glyph for the end of a truncated screen line (the default for this
|
1999-09-17 06:59:04 +00:00
|
|
|
is @samp{$}). @xref{Glyphs}. Newer Emacs versions, on some platforms,
|
|
|
|
display arrows to indicate truncation---the display table has no effect
|
|
|
|
in these situations.
|
1998-02-28 01:53:53 +00:00
|
|
|
@item 1
|
1994-03-30 18:36:47 +00:00
|
|
|
The glyph for the end of a continued line (the default is @samp{\}).
|
1999-09-17 06:59:04 +00:00
|
|
|
Newer Emacs versions, on some platforms, display curved arrows to
|
|
|
|
indicate truncation---the display table has no effect in these
|
|
|
|
situations.
|
1998-02-28 01:53:53 +00:00
|
|
|
@item 2
|
1994-03-30 18:36:47 +00:00
|
|
|
The glyph for indicating a character displayed as an octal character
|
|
|
|
code (the default is @samp{\}).
|
1998-02-28 01:53:53 +00:00
|
|
|
@item 3
|
1994-03-30 18:36:47 +00:00
|
|
|
The glyph for indicating a control character (the default is @samp{^}).
|
1998-02-28 01:53:53 +00:00
|
|
|
@item 4
|
1994-03-30 18:36:47 +00:00
|
|
|
A vector of glyphs for indicating the presence of invisible lines (the
|
|
|
|
default is @samp{...}). @xref{Selective Display}.
|
1998-02-28 01:53:53 +00:00
|
|
|
@item 5
|
1994-09-19 21:50:07 +00:00
|
|
|
The glyph used to draw the border between side-by-side windows (the
|
1999-09-17 06:59:04 +00:00
|
|
|
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.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end table
|
|
|
|
|
|
|
|
For example, here is how to construct a display table that mimics the
|
|
|
|
effect of setting @code{ctl-arrow} to a non-@code{nil} value:
|
|
|
|
|
|
|
|
@example
|
|
|
|
(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 ?^ ??)))
|
|
|
|
@end example
|
|
|
|
|
1998-02-28 01:53:53 +00:00
|
|
|
@defun display-table-slot display-table slot
|
|
|
|
This function returns the value of the extra slot @var{slot} of
|
|
|
|
@var{display-table}. The argument @var{slot} may be a number from 0 to
|
|
|
|
5 inclusive, or a slot name (symbol). Valid symbols are
|
|
|
|
@code{truncation}, @code{wrap}, @code{escape}, @code{control},
|
|
|
|
@code{selective-display}, and @code{vertical-border}.
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
@defun set-display-table-slot display-table slot value
|
|
|
|
This function stores @var{value} in the extra slot @var{slot} of
|
|
|
|
@var{display-table}. The argument @var{slot} may be a number from 0 to
|
|
|
|
5 inclusive, or a slot name (symbol). Valid symbols are
|
|
|
|
@code{truncation}, @code{wrap}, @code{escape}, @code{control},
|
|
|
|
@code{selective-display}, and @code{vertical-border}.
|
|
|
|
@end defun
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@defun describe-display-table display-table
|
|
|
|
@tindex describe-display-table
|
|
|
|
This function displays a description of the display table
|
|
|
|
@var{display-table} in a help buffer.
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
@deffn Command describe-current-display-table
|
|
|
|
@tindex describe-current-display-table
|
|
|
|
This command displays a description of the current display table in a
|
|
|
|
help buffer.
|
|
|
|
@end deffn
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@node Active Display Table
|
|
|
|
@subsection Active Display Table
|
|
|
|
@cindex 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.
|
|
|
|
|
|
|
|
@defun window-display-table window
|
|
|
|
This function returns @var{window}'s display table, or @code{nil}
|
|
|
|
if @var{window} does not have an assigned display table.
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
@defun 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
|
|
|
|
@code{nil}.
|
|
|
|
@end defun
|
|
|
|
|
|
|
|
@defvar buffer-display-table
|
1998-04-20 17:43:57 +00:00
|
|
|
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.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end defvar
|
|
|
|
|
|
|
|
@defvar 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.
|
|
|
|
@end defvar
|
|
|
|
|
|
|
|
If there is no display table to use for a particular window---that is,
|
1998-02-28 01:53:53 +00:00
|
|
|
if the window specifies none, its buffer specifies none, and
|
|
|
|
@code{standard-display-table} is @code{nil}---then Emacs uses the usual
|
1994-03-30 18:36:47 +00:00
|
|
|
display conventions for all character codes in that window. @xref{Usual
|
|
|
|
Display}.
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
A number of functions for changing the standard display table
|
|
|
|
are defined in the library @file{disp-table}.
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@node Glyphs
|
|
|
|
@subsection Glyphs
|
|
|
|
|
|
|
|
@cindex 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. Glyphs
|
|
|
|
are represented in Lisp as integers, just as characters are.
|
|
|
|
|
|
|
|
@cindex glyph table
|
|
|
|
The meaning of each integer, as a glyph, is defined by the glyph
|
|
|
|
table, which is the value of the variable @code{glyph-table}.
|
|
|
|
|
|
|
|
@defvar glyph-table
|
|
|
|
The value of this variable is the current glyph table. It should be a
|
|
|
|
vector; the @var{g}th element defines glyph code @var{g}. If the value
|
|
|
|
is @code{nil} instead of a vector, then all glyphs are simple (see
|
2001-09-08 17:49:11 +00:00
|
|
|
below). The glyph table is not used on windowed displays.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end defvar
|
|
|
|
|
|
|
|
Here are the possible types of elements in the glyph table:
|
|
|
|
|
1998-05-26 18:56:56 +00:00
|
|
|
@table @asis
|
|
|
|
@item @var{string}
|
1994-03-30 18:36:47 +00:00
|
|
|
Send the characters in @var{string} to the terminal to output
|
|
|
|
this glyph. This alternative is available on character terminals,
|
1998-04-20 17:43:57 +00:00
|
|
|
but not under a window system.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1998-05-26 18:56:56 +00:00
|
|
|
@item @var{integer}
|
1998-04-20 17:43:57 +00:00
|
|
|
Define this glyph code as an alias for glyph code @var{integer}. You
|
|
|
|
can use an alias to specify a face code for the glyph; see below.
|
1994-03-30 18:36:47 +00:00
|
|
|
|
|
|
|
@item @code{nil}
|
2002-01-18 11:44:40 +00:00
|
|
|
This glyph is simple. The glyph code mod 524288 is the character to
|
|
|
|
output, and the glyph code divided by 524288 specifies the face number
|
|
|
|
(@pxref{Face Functions}) to use while outputting it. (524288 is
|
2000-01-05 15:18:01 +00:00
|
|
|
@ifnottex
|
1998-04-20 17:43:57 +00:00
|
|
|
2**19.)
|
2000-01-05 15:18:01 +00:00
|
|
|
@end ifnottex
|
1998-02-28 01:53:53 +00:00
|
|
|
@tex
|
1998-04-20 17:43:57 +00:00
|
|
|
$2^{19}$.)
|
1998-02-28 01:53:53 +00:00
|
|
|
@end tex
|
|
|
|
@xref{Faces}.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end table
|
|
|
|
|
|
|
|
If a glyph code is greater than or equal to the length of the glyph
|
|
|
|
table, that code is automatically simple.
|
|
|
|
|
1999-09-17 06:59:04 +00:00
|
|
|
@defun create-glyph string
|
|
|
|
@tindex create-glyph
|
|
|
|
This function returns a newly-allocated glyph code which is set up to
|
|
|
|
display by sending @var{string} to the terminal.
|
|
|
|
@end defun
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@node Beeping
|
|
|
|
@section Beeping
|
|
|
|
@cindex beeping
|
|
|
|
@cindex bell
|
|
|
|
|
1998-02-28 01:53:53 +00:00
|
|
|
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}.)
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1998-05-19 03:45:57 +00:00
|
|
|
@defun ding &optional do-not-terminate
|
1994-03-30 18:36:47 +00:00
|
|
|
@cindex keyboard macro termination
|
|
|
|
This function beeps, or flashes the screen (see @code{visible-bell} below).
|
|
|
|
It also terminates any keyboard macro currently executing unless
|
1998-05-19 03:45:57 +00:00
|
|
|
@var{do-not-terminate} is non-@code{nil}.
|
1994-03-30 18:36:47 +00:00
|
|
|
@end defun
|
|
|
|
|
1998-05-19 03:45:57 +00:00
|
|
|
@defun beep &optional do-not-terminate
|
1994-03-30 18:36:47 +00:00
|
|
|
This is a synonym for @code{ding}.
|
|
|
|
@end defun
|
|
|
|
|
1998-05-26 18:56:56 +00:00
|
|
|
@defopt visible-bell
|
1994-03-30 18:36:47 +00:00
|
|
|
This variable determines whether Emacs should flash the screen to
|
|
|
|
represent a bell. Non-@code{nil} means yes, @code{nil} means no. This
|
1998-04-20 17:43:57 +00:00
|
|
|
is effective on a window system, and on a character-only terminal
|
|
|
|
provided the terminal's Termcap entry defines the visible bell
|
|
|
|
capability (@samp{vb}).
|
1998-05-26 18:56:56 +00:00
|
|
|
@end defopt
|
1994-03-30 18:36:47 +00:00
|
|
|
|
1998-02-28 01:53:53 +00:00
|
|
|
@defvar ring-bell-function
|
|
|
|
If this is non-@code{nil}, it specifies how Emacs should ``ring the
|
1999-10-05 23:26:05 +00:00
|
|
|
bell.'' Its value should be a function of no arguments. If this is
|
|
|
|
non-@code{nil}, it takes precedence over the @code{visible-bell}
|
|
|
|
variable.
|
1998-02-28 01:53:53 +00:00
|
|
|
@end defvar
|
|
|
|
|
1994-03-30 18:36:47 +00:00
|
|
|
@node Window Systems
|
|
|
|
@section 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.
|
|
|
|
|
|
|
|
@defvar window-system
|
|
|
|
This variable tells Lisp programs what window system Emacs is running
|
1998-05-26 18:56:56 +00:00
|
|
|
under. The possible values are
|
|
|
|
|
|
|
|
@table @code
|
|
|
|
@item x
|
|
|
|
@cindex X Window System
|
|
|
|
Emacs is displaying using X.
|
|
|
|
@item pc
|
1999-09-17 06:59:04 +00:00
|
|
|
Emacs is displaying using MS-DOS.
|
1998-05-26 18:56:56 +00:00
|
|
|
@item w32
|
2000-01-16 00:29:04 +00:00
|
|
|
Emacs is displaying using Windows.
|
1999-09-17 06:59:04 +00:00
|
|
|
@item mac
|
|
|
|
Emacs is displaying using a Macintosh.
|
1998-05-26 18:56:56 +00:00
|
|
|
@item nil
|
|
|
|
Emacs is using a character-based terminal.
|
|
|
|
@end table
|
1994-03-30 18:36:47 +00:00
|
|
|
@end defvar
|
|
|
|
|
|
|
|
@defvar window-setup-hook
|
1998-02-28 01:53:53 +00:00
|
|
|
This variable is a normal hook which Emacs runs after handling the
|
|
|
|
initialization files. Emacs runs this hook after it has completed
|
1999-10-05 23:26:05 +00:00
|
|
|
loading your init file, the default initialization file (if
|
1998-05-19 03:45:57 +00:00
|
|
|
any), and the terminal-specific Lisp code, and running the hook
|
1994-03-30 18:36:47 +00:00
|
|
|
@code{term-setup-hook}.
|
|
|
|
|
|
|
|
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.
|
|
|
|
@end defvar
|