@c -*-texinfo-*-
@c This is part of the GNU Emacs Lisp Reference Manual.
-@c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1998 Free Software Foundation, Inc.
+@c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1998, 1999, 2000, 2001, 2002
+@c Free Software Foundation, Inc.
@c See the file elisp.texi for copying conditions.
@setfilename ../info/display
@node Display, Calendar, Processes, Top
which is also called @dfn{continuing} the line. (The display table can
specify alternative indicators; see @ref{Display Tables}.)
+@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}.
+
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}.
follows:
@defun message string &rest arguments
-This function displays a one-line message in the echo area. The
+This function displays a message in the echo area. The
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
its normal size. If the minibuffer is active, this brings the
minibuffer contents back onto the screen immediately.
+@vindex message-truncate-lines
+Normally, displaying a long message resizes the echo area to display
+the entire message. But if the variable @code{message-truncate-lines}
+is non-@code{nil}, the echo area does not resize, and the message is
+truncated to fit it, as in Emacs 20 and before.
+
@example
@group
(message "Minibuffer depth is %d."
---------- Echo Area ----------
@end group
@end example
+
+To automatically display a message in the echo area or in a pop-buffer,
+depending on its size, use @code{display-message-or-buffer}.
@end defun
@tindex with-temp-message
@code{message}.
@end defun
+@defun display-message-or-buffer message &optional buffer-name not-this-window frame
+@tindex display-message-or-buffer
+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
+
@defun current-message
-@tindex current-message
This function returns the message currently being displayed in the
echo area, or @code{nil} if there is none.
@end defun
@end defvar
@defvar echo-area-clear-hook
-@tindex 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
@defvar echo-keystrokes
This variable determines how much time should elapse before command
-characters echo. Its value must be an integer, which specifies the
+characters echo. Its value must be an integer or floating point number,
+which specifies the
number of seconds to wait before echoing. If the user types a prefix
key (such as @kbd{C-x}) and then delays this many seconds before
continuing, the prefix key is echoed in the echo area. (Once echoing
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
-@code{invisible} property works.
+@code{invisible} property works. You should normally use @code{t}
+as the value of the @code{invisible} property if you don't plan
+to set @code{buffer-invisibility-spec} yourself.
More generally, you can use the variable @code{buffer-invisibility-spec}
to control which values of the @code{invisible} property make text
@code{buffer-invisibility-spec} and removing elements from it.
@defun add-to-invisibility-spec element
-@tindex add-to-invisibility-spec
-Add the element @var{element} to @code{buffer-invisibility-spec}
-(if it is not already present in that list).
+This function adds the element @var{element} to
+@code{buffer-invisibility-spec} (if it is not already present in that
+list). If @code{buffer-invisibility-spec} was @code{t}, it changes to
+a list, @code{(t)}, so that text whose @code{invisible} property
+is @code{t} remains invisible.
@end defun
@defun remove-from-invisibility-spec element
-@tindex remove-from-invisibility-spec
-Remove the element @var{element} from @code{buffer-invisibility-spec}.
-This does nothing if @var{element} is not in the list.
+This removeds the element @var{element} from
+@code{buffer-invisibility-spec}. This does nothing if @var{element}
+is not in the list.
@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:
+ A convention for use of @code{buffer-invisibility-spec} is that a
+major mode should use the mode's own name as an element of
+@code{buffer-invisibility-spec} and as the value of the
+@code{invisible} property:
@example
;; @r{If you want to display an ellipsis:}
want this to be done differently for a certain overlay, give it an
@code{isearch-open-invisible-temporary} property which is a function.
The function is called with two arguments: the first is the overlay, and
-the second is @code{t} to make the overlay visible, or @code{nil} to
+the second is @code{nil} to make the overlay visible, or @code{t} to
make it invisible again.
@node Selective Display
about to be executed.
@defvar overlay-arrow-string
+@cindex fringe, and overlay arrow display
This variable holds the string to display to call attention to a
particular line, or @code{nil} if the arrow feature is not in use.
+On a graphical display the contents of the string are ignored; instead a
+glyph is displayed in the fringe area to the left of the display area.
@end defvar
@defvar overlay-arrow-position
This variable holds a marker that indicates where to display the overlay
-arrow. It should point at the beginning of a line. The arrow text
+arrow. It should point at the beginning of a line. On a non-graphical
+display the arrow text
appears at the beginning of that line, overlaying any text that would
otherwise appear. Since the arrow is usually short, and the line
usually begins with indentation, normally nothing significant is
@defvar temp-buffer-setup-hook
@tindex temp-buffer-setup-hook
This normal hook is run by @code{with-output-to-temp-buffer} before
-evaluating @var{body}. When the hook runs, the help buffer is current.
-This hook is normally set up with a function to put the buffer in Help
-mode.
+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.
@end defvar
@defvar temp-buffer-show-hook
This normal hook is run by @code{with-output-to-temp-buffer} after
-displaying the help buffer. When the hook runs, the help 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
-still Help mode.
+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.
@end defvar
@defun momentary-string-display string position &optional char message
@menu
* Overlay Properties:: How to read and set properties.
What properties do to the screen display.
-* Managing Overlays:: Creating, moving, finding overlays.
+* Managing Overlays:: Creating and moving overlays.
+* Finding Overlays:: Searching for overlays.
@end menu
@node Overlay Properties
@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
-or shorter, higher or lower, wider or narror, or replaced with an image.
+or shorter, higher or lower, wider or narrower, or replaced with an image.
@xref{Display Property}.
@item help-echo
@kindex help-echo @r{(text property)}
-If an overlay has a string as its @code{help-echo} property, then when
-you move the mouse onto the text in the overlay, Emacs displays that
-string in the echo area, or in the tooltip window. This feature is
-available starting in Emacs 21.
+If an overlay has a @code{help-echo} property, then when you move the
+mouse onto the text in the overlay, Emacs displays a help string in the
+echo area, or in the tooltip window. For details see @ref{Text
+help-echo}.
@item modification-hooks
@kindex modification-hooks @r{(overlay property)}
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}.
+
+@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.
@end table
@node Managing Overlays
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
-overlay. @xref{Marker Insertion Types}.
+overlay, respectively. @xref{Marker Insertion Types}.
@end defun
@defun overlay-start overlay
@defun delete-overlay overlay
This function deletes @var{overlay}. The overlay continues to exist as
-a Lisp object, but ceases to be attached to the buffer it belonged to,
-and ceases to have any effect on display.
+a Lisp object, and its property list is unchanged, but it ceases to be
+attached to the buffer it belonged to, and ceases to have any effect on
+display.
-A deleted overlay is not permanently useless. You can give it
-a position in a buffer again by calling @code{move-overlay}.
+A deleted overlay is not permanently disconnected. You can give it a
+position in a buffer again by calling @code{move-overlay}.
@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}
-must specify buffer positions; they may be integers or markers. If
-@var{buffer} is omitted, @var{overlay} stays in the same buffer;
-if @var{overlay} was deleted, it goes into the current buffer.
+must specify buffer positions; they may be integers or markers.
+
+If @var{buffer} is omitted, @var{overlay} stays in the same buffer it
+was already associated with; if @var{overlay} was deleted, it goes into
+the current buffer.
The return value is @var{overlay}.
``lost''.
@end defun
+ 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>
+;; @r{Moving and deleting the overlay does not change its properties.}
+(overlay-get foo 'happy)
+ @result{} t
+@end example
+
+@node Finding Overlays
+@subsection Searching for Overlays
+
@defun overlays-at pos
-This function returns a list of all the overlays that contain 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}.
+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
+ (let ((overlay (car overlays)))
+ (if (overlay-get overlay prop)
+ (setq found (cons overlay found))))
+ (setq overlays (cdr overlays)))
+ found))
+@end smallexample
@end defun
@defun overlays-in beg end
-@tindex overlays-in
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
-they are located at @var{beg} or between @var{beg} and @var{end}.
+they are located at @var{beg}, or strictly between @var{beg} and @var{end}.
@end defun
@defun next-overlay-change pos
end of an overlay, before @var{pos}.
@end defun
+ 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
+
@node Width
@section Width
@ref{Screen Lines}, for related functions.
@defun char-width char
-@tindex char-width
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
-@tindex string-width
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
-@tindex truncate-string-to-width
This function returns the part of @var{string} that fits within
@var{width} columns, as a new string.
@node Faces
@section Faces
-@cindex face
+@cindex faces
A @dfn{face} is a named collection of graphical attributes: font
family, foreground color, background color, optional underlining, and
@item mode-line
@kindex mode-line @r{(face name)}
-This face is used for mode lines, and for menu bars when toolkit menus
-are not used---but only if @code{mode-line-inverse-video} is
-non-@code{nil}.
+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}.
@item modeline
@kindex modeline @r{(face name)}
This is an alias for the @code{mode-line} face, for compatibility with
old Emacs versions.
+@item mode-line-inactive
+@kindex mode-line-inactive @r{(face name)}
+This face is used for mode lines of non-selected windows.
+This face inherits from @code{mode-line}, so changes
+in that face affect all windows.
+
@item header-line
@kindex header-line @r{(face name)}
This face is used for the header lines of windows that have them.
This face controls the colors of window fringes, the thin areas on
either side that are used to display continuation and truncation glyphs.
+@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.
+
@item scroll-bar
@kindex scroll-bar @r{(face name)}
This face controls the colors for display of scroll bars.
@kindex underline @r{(face name)}
This face underlines text.
-@item fixed-patch
-@kindex fixed-patch @r{(face name)}
+@item fixed-pitch
+@kindex fixed-pitch @r{(face name)}
This face forces use of a particular fixed-width font.
-@item variable-patch
-@kindex variable-patch @r{(face name)}
+@item variable-pitch
+@kindex variable-pitch @r{(face name)}
This face forces use of a particular variable-width font. It's
reasonable to customize this to use a different variable-width font, if
you like, but you should not make it a fixed-width font.
emacs, The GNU Emacs Manual}).
@defmac defface face spec doc [keyword value]...
-@tindex defface
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
@table @code
@item type
-The kind of window system the frame uses---either @code{x}, @code{pc}
-(for the MS-DOS console), @code{w32} (for MS Windows 9X/NT), or
-@code{tty}.
+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).
@item class
What kinds of colors the frame supports---either @code{color},
@item background
The kind of background---either @code{light} or @code{dark}.
+
+@item supports
+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}.
@end table
If an element of @var{display} specifies more than one @var{value} for a
with the customization buffer, and @code{face-documentation} for the
documentation string.
-@tindex frame-background-mode
@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
@code{extra-expanded}, or @code{ultra-expanded}.
@item :height
-Font height, an integer in units of 1/10 point.
+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.
@item :weight
Font weight---a symbol from this series (from most dense to most faint):
@code{normal}, @code{semi-light}, @code{light}, @code{extra-light},
or @code{ultra-light}.
-On a text-only terminal, any weight greater than normal is displayed as
-extra bright, and any weight less than normal is displayed as
-half-bright (This is provided the terminal supports the feature.)
-
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).
external-format X bitmap data. The file is found in the directories
listed in the variable @code{x-bitmap-file-path}.
-Alternatively, the value can specify the bitmap directly, with a list of
-the form @code{(@var{width} @var{height} @var{data})}. Here,
-@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} consecutie bytes in the string
-(which should be a unibyte string for best results).
+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.
If the value is @code{nil}, that means use no stipple pattern.
Whether or not characters should be strike-through, and in what
color. The value is used like that of @code{:underline}.
+@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.
+
@item :box
Whether or not a box should be drawn around characters, its color, the
width of the box lines, and 3D appearance.
@end defvar
@defun bitmap-spec-p object
-This returns @code{t} if @var{object} is a valid bitmap
-specification, suitable for use with @code{:stipple}.
-It returns @code{nil} otherwise.
+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.
@end defun
@node Attribute Functions
@example
(set-face-attribute 'foo nil
- :width :extended
- :weight :bold
+ :width 'extended
+ :weight 'bold
:underline "red")
@end example
@end defun
@tindex face-attribute
-@defun face-attribute face attribute &optional frame
+@defun face-attribute face attribute &optional frame inherit
This returns the value of the @var{attribute} attribute of face
@var{face} on @var{frame}. If @var{frame} is @code{nil},
-that means the selected frame.
+that means the selected frame (@pxref{Input Focus}).
If @var{frame} is @code{t}, the value is the default for
@var{face} for new frames.
+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).
+
For example,
@example
with older Emacs versions, you can use the following functions to set
and examine the face attributes which existed in those versions.
+@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
+
@defun set-face-foreground face color &optional frame
@defunx set-face-background face color &optional frame
These functions set the foreground (or background, respectively) color
@end defun
@defun set-face-stipple face pattern &optional frame
-This function sets the background stipple pattern of face @var{face} to
-@var{pattern}. The argument @var{pattern} should be the name of a
-stipple pattern defined by the X server, or @code{nil} meaning don't use
-stipple.
+This function sets the background stipple pattern of face @var{face}
+to @var{pattern}. The argument @var{pattern} should be the name of a
+stipple pattern defined by the X server, or actual bitmap data
+(@pxref{Face Attributes}), or @code{nil} meaning don't use stipple.
Normally there is no need to pay attention to stipple patterns, because
they are used automatically to handle certain shades of gray.
@end defun
@defun set-face-bold-p face bold-p &optional frame
-@tindex set-face-bold-p
This function specifies whether @var{face} should be bold. If
@var{bold-p} is non-@code{nil}, that means yes; @code{nil} means no.
@end defun
@defun set-face-italic-p face italic-p &optional frame
-@tindex set-face-italic-p
This function specifies whether @var{face} should be italic. If
@var{italic-p} is non-@code{nil}, that means yes; @code{nil} means no.
They return the symbol @code{unspecified} if the face doesn't define any
value for that attribute.
-@defun face-foreground face &optional frame
+@defun face-foreground face &optional frame inherit
@defunx face-background face &optional frame
These functions return the foreground color (or background color,
respectively) of face @var{face}, as a string.
+
+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}.
@end defun
-@defun face-stipple face &optional frame
+@defun face-stipple face &optional frame inherit
This function returns the name of the background stipple pattern of face
@var{face}, or @code{nil} if it doesn't have one.
+
+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}.
@end defun
@defun face-font face &optional frame
@end defun
@defun face-bold-p face &optional frame
-@tindex face-bold-p
This function returns @code{t} if @var{face} is bold---that is, if it is
bolder than normal. It returns @code{nil} otherwise.
@end defun
@defun face-italic-p face &optional frame
-@tindex face-italic-p
This function returns @code{t} if @var{face} is italic or oblique,
@code{nil} otherwise.
@end defun
and character's registry and encoding. If there is a font that matches
exactly, it is used, of course. The hard case is when no available font
exactly fits the specification. Then Emacs looks for one that is
-``close''---one attribute at a time. You can specify the order
-to consider the attributes.
+``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.
@defvar face-font-selection-order
@tindex face-font-selection-order
quite right.
@end defvar
-@defvar face-alternative-font-family-alist
-@tindex face-alternative-font-family-alist
+@defvar face-font-family-alternatives
+@tindex face-font-family-alternatives
This variable lets you specify alternative font families to try, if a
given family is specified and doesn't exist. Each element should have
this form:
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.
+@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.
@end defvar
Emacs can make use of scalable fonts, but by default it does not use
@noindent
allows the use of scalable fonts with registry @code{muleindian-2}.
-@end example
@end defvar
@defun clear-face-cache &optional unload-p
@end defun
@defun face-documentation face
-@tindex face-documentation
This function returns the documentation string of face @var{face}, or
@code{nil} if none was specified for it.
@end defun
contain the wildcards @samp{?} and @samp{*}.
The list describes the display that @var{frame} is on; if @var{frame} is
-omitted or @code{nil}, it applies to the selected frame's display.
+omitted or @code{nil}, it applies to the selected frame's display
+(@pxref{Input Focus}).
The list contains a vector of the following form for each font:
@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
-describes the selected frame's display.
+describes the selected frame's display (@pxref{Input Focus}).
The value is a list of elements of this form:
@end example
@noindent
-the font specification for ASCII characters would be this:
+the font specification for @sc{ascii} characters would be this:
@example
-*-fixed-medium-r-normal-*-24-*-ISO8859-1
values). You can put this property on one or more consecutive
characters; a space of the specified height and width is displayed in
place of @emph{all} of those characters. These are the properties you
-can use to specify the weight of the space:
+can use in @var{props} to specify the weight of the space:
@table @code
@item :width @var{width}
@item :align-to @var{hpos}
Specifies that the space should be wide enough to reach @var{hpos}. The
value @var{hpos} is measured in units of the normal character width. It
-may be an interer or a floating point number.
+may be an integer or a floating point number.
@end table
- Exactly one of the above properties should be used. You can also
-specify the height of the space, with other properties:
+ You should use one and only one of the above properties. You can
+also specify the height of the space, with other properties:
@table @code
@item :height @var{height}
greater than 100.
@end table
- You should not use both @code{:height} and @code{:relative-height}
-together.
+ Don't use both @code{:height} and @code{:relative-height} together.
@node Other Display Specs
@subsection Other Display Specifications
display specification, it means to display the image instead of the text
that has the display specification.
+@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}).
+
+Recursive display specifications are not supported---string display
+specifications must not have @code{display} properties themselves.
+
@item (space-width @var{factor})
This display specification affects all the space characters within the
text that has the specification. It displays all of these spaces
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
-the image.
+the image. Unfortunately, there is currently no way to make
+text or images in the margin mouse-sensitive.
+
+ If you put such a display specification directly on text in the
+buffer, the specified margin display appears @emph{instead of} that
+buffer text itself. To put something in the margin @emph{in
+association with} certain buffer text without preventing or altering
+the display of that text, put a @code{before-string} property on the
+text and put the display specification on the contents of the
+before-string.
Before the display margins can display anything, you must give
them a nonzero width. The usual way to do that is to set these
You can also set the margin widths immediately.
-@defun set-window-margins window left right
+@defun set-window-margins window left &optional right
@tindex set-window-margins
This function specifies the margin widths for window @var{window}.
The argument @var{left} controls the left margin and
-@var{right} controls the right margin.
+@var{right} controls the right margin (default @code{0}).
@end defun
@defun window-margins &optional window
@cindex conditional display specifications
You can make any display specification conditional. To do that,
-package it in another list of the form @code{(when @var{condition}
+package it in another list of the form @code{(when @var{condition} .
@var{spec})}. Then the specification @var{spec} applies only when
@var{condition} evaluates to a non-@code{nil} value. During the
-evaluation, point is temporarily set at the end position of the text
-having this conditional display specification.
+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.
@node Images
@section Images
types:
@table @code
-@item :ascent @var{ascent}
-The @code{:ascent} property specifies the percentage 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. If this
-property is omitted, it defaults to 50.
+@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
-non-negative number; if it is not specified, the default is zero.
+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.
+
+@item :ascent @var{ascent}
+The @code{:ascent} property specifies the amount of the image's
+height to use for its ascent---that is, the part above the baseline.
+The value, @var{ascent}, must be a number in the range 0 to 100, or
+the symbol @code{center}.
+
+If @var{ascent} is a number, that percentage of the image's height is
+used for its ascent.
+
+If @var{ascent} is @code{center}, the image is vertically centered
+around a centerline which would be the vertical centerline of text drawn
+at the position of the image, in the manner specified by the text
+properties and overlays that apply to the image.
+
+If this property is omitted, it defaults to 50.
@item :relief @var{relief}
The @code{:relief} property, if non-@code{nil}, adds a shadow rectangle
so that the image appears as a pressed button; otherwise, it appears as
an unpressed button.
-@item :algorithm @var{algorithm}
-The @code{:algorithm} property, if non-@code{nil}, specifies a
+@item :conversion @var{algorithm}
+The @code{:conversion} property, if non-@code{nil}, specifies a
conversion algorithm that should be applied to the image before it is
displayed; the value, @var{algorithm}, specifies which algorithm.
-Currently, the only meaningful value for @var{algorithm} (aside from
-@code{nil}) is @code{laplace}; this applies 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 :heuristic-mask @var{transparent-color}
-The @code{:heuristic-mask} property, if non-@code{nil}, specifies that a
-certain color in the image should be transparent. Each pixel where this
-color appears will actually allow the frame's background to show
-through.
-
-If @var{transparent-color} is @code{t}, then determine the transparent
-color by looking at the four corners of the image. This uses the color
-that occurs most frequently near the corners as the transparent color.
-
-Otherwise, @var{heuristic-mask} should specify the transparent color
-directly, as a list of three integers in the form @code{(@var{red}
-@var{green} @var{blue})}.
-
-@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.
-However, only certain image types support @code{:data}; for other types,
-you must use @code{:file}.
+@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
-The formats that support @code{:data} include XBM and XPM.
-Before using @code{:data}, see the section describing the specific
-format you wish to use for further information.
+@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.
+
+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}.
@end table
+@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.
+@var{frame} @code{nil} or omitted means to use the selected frame
+(@pxref{Input Focus}).
+@end defun
+
@node XBM Images
@subsection XBM Images
@cindex XBM
@table @code
@item :foreground @var{foreground}
The value, @var{foreground}, should be a string specifying the image
-foreground color. This color is used for each pixel in the XBM that is
-1. The default is the frame's foreground color.
+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.
@item :background @var{background}
The value, @var{background}, should be a string specifying the image
-background color. This color is used for each pixel in the XBM that is
-0. The default is the frame's background color.
+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.
@end table
- You can specify an XBM image using data within Emacs instead
-of an external file. To do this, don't use @code{:file}; instead,
-use the following three properties (all of them):
+ If you specify an XBM image using data within Emacs instead of an
+external file, use the following three properties:
@table @code
-@item :width @var{width}
-The value, @var{width}, specifies the width the image in pixels.
+@item :data @var{data}
+The value, @var{data}, specifies the contents of the image.
+There are three formats you can use for @var{data}:
-@item :height @var{height}
-The value, @var{height}, specifies the height of the image in pixels.
+@itemize @bullet
+@item
+A vector of strings or bool-vectors, each specifying one line of the
+image. Do specify @code{:height} and @code{:width}.
-@item :data @var{data}
-The value, @var{data}, is normally a string or a bool-vector. Either
-way, it must contain enough bits for the area of the image: at least
-@var{width} * @code{height}.
+@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.
-Alternatively, @var{data} can be a vector of strings or bool-vectors,
-each specifying one line of the image.
+@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.
@end table
@node XPM Images
@subsection XPM Images
@cindex XPM
- To use XPM format, specify @code{xpm} as the image type. These
-additional image properties are meaningful with the @code{xpm} image
-type:
+ 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:
@table @code
@item :color-symbols @var{symbols}
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.
-
-@item :data @var{data}
-XPM images can be displayed from data instead of files. In that case,
-use the @code{:data} property instead of the @code{:file} property.
-
-The value @var{data} must be a string containing an XPM image. The
-contents of the string have same format as an external XPM file.
@end table
@node GIF Images
@end example
@end table
+ Displaying Postscript images from Lisp data is not currently
+implemented, but it may be implemented by the time you read this.
+See the @file{etc/NEWS} file to make sure.
+
@node Other Image Types
@subsection Other Image Types
@cindex PBM
For PBM images, specify image type @code{pbm}. Color, gray-scale and
-monochromatic images are supported.
+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
+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.
+
+@item :background @var{background}
+The value, @var{background}, should be a string specifying the image
+background color, or @code{nil} for the default color. This color is
+used for each pixel in the XBM that is 0. The default is the frame's
+background color.
+@end table
- For JPEG images, specify image type @code{jpeg}. There are no
-additional image properties defined.
+ For JPEG images, specify image type @code{jpeg}.
For TIFF images, specify image type @code{tiff}.
@node Defining Images
@subsection Defining Images
- The functions @code{create-image} and @code{defimage} provide
-convenient ways to create image descriptors.
+ The functions @code{create-image}, @code{defimage} and
+@code{find-image} provide convenient ways to create image descriptors.
@defun create-image file &optional type &rest props
@tindex create-image
supported. Otherwise it returns an image descriptor.
@end defun
-@defmac defimage variable doc &rest specs
+@defmac defimage symbol specs &optional doc
@tindex defimage
-This macro defines @var{variable} as an image name. The second argument,
-@var{doc}, is an optional documentation string. The remaining
-arguments, @var{specs}, specify alternative ways to display the image.
+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.
Each argument in @var{specs} has the form of a property list, and each
-one should specify at least the @code{:type} property and the
-@code{:file} property. Here is an example:
+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:
@example
(defimage test-image
- '((:type xpm :file "~/test1.xpm")
- (:type xbm :file "~/test1.xbm")))
+ ((:type xpm :file "~/test1.xpm")
+ (:type xbm :file "~/test1.xbm")))
@end example
@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
-stored in the variable @var{variable}.
+stored in @var{symbol}.
-If none of the alternatives will work, then @var{variable} is defined
+If none of the alternatives will work, then @var{symbol} is defined
as @code{nil}.
@end defmac
+@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
+
@node Showing Images
@subsection Showing Images
property yourself, but it is easier to use the functions in this
section.
-@defun insert-image image string &optional area
+@defun insert-image image &optional string area
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
Property}.
@end defun
-@defun put-image image pos string &optional area
+@defun put-image image pos &optional string area
This function puts image @var{image} in front of @var{pos} in the
current buffer. The argument @var{pos} should be an integer or a
marker. It specifies the buffer position where the image should appear.
-The argument @var{string} specifies the text that should hold the image.
+The argument @var{string} specifies the text that should hold the image
+as an alternative to the default.
The argument @var{image} must be an image descriptor, perhaps returned
by @code{create-image} or stored by @code{defimage}.
@var{start} and @var{end}. If @var{buffer} is omitted or @code{nil},
images are removed from the current buffer.
-This remove only images that were put into @var{buffer} the way
+This removes only images that were put into @var{buffer} the way
@code{put-image} does it, not images that were inserted with
@code{insert-image} or in other ways.
@end defun
+@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.
+@var{frame} null or omitted means use the selected frame (@pxref{Input
+Focus}).
+@end defun
+
@node Image Cache
@subsection Image Cache
display them again more efficiently. It removes an image from the cache
when it hasn't been displayed for a specified period of time.
+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.
+
@defvar image-cache-eviction-delay
@tindex image-cache-eviction-delay
This variable specifies the number of seconds an image can remain in the
only the cache for that frame is cleared. Otherwise all frames' caches
are cleared.
@end defun
+
@node Blinking
@section Blinking Parentheses
@cindex parenthesis matching
@defopt mode-line-inverse-video
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
-inverse video. Otherwise, they lines are displayed normally, just like
+inverse video. Otherwise, these lines are displayed normally, just like
other text. The default is @code{t}.
For window frames, this feature actually applies the face named
buffers that do not override it. @xref{Default Value}.
@end defvar
+@defopt indicate-empty-lines
+@tindex indicate-empty-lines
+@cindex fringes, and empty line indication
+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
+
@defopt tab-width
The value of this variable is the spacing between tab stops used for
displaying tab characters in Emacs buffers. The value is in units of
@end example
@defun display-table-slot display-table slot
-@tindex 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
@end defun
@defun set-display-table-slot display-table slot value
-@tindex set-display-table-slot
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
@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.
+are represented in Lisp as integers, just as characters are. Normally
+Emacs finds glyphs in the display table (@pxref{Display Tables}).
+
+ A glyph can be @dfn{simple} or it can be defined by the @dfn{glyph
+table}. A simple glyph is just a way of specifying a character and a
+face to output it in. The glyph code for a simple glyph, 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
+@ifnottex
+2**19.)
+@end ifnottex
+@tex
+$2^{19}$.)
+@end tex
+@xref{Faces}.
-@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}.
+ On character terminals, you can set up a @dfn{glyph table} to define
+the meaning of glyph codes. The glyph codes 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
-below).
+vector; the @var{g}th element defines glyph code @var{g}.
+
+If a glyph code is greater than or equal to the length of the glyph
+table, that code is automatically simple. If the value of
+@code{glyph-table} is @code{nil} instead of a vector, then all glyphs
+are simple. The glyph table is not used on graphical displays, only
+on character terminals. On graphical displays, all glyphs are simple.
@end defvar
Here are the possible types of elements in the glyph table:
@item @var{integer}
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.
+can use an alias to specify a face code for the glyph and use a small
+number as its code.
@item @code{nil}
-This glyph is simple. On an ordinary terminal, the glyph code mod
-524288 is the character to output. In a window system, 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
-@ifinfo
-2**19.)
-@end ifinfo
-@tex
-$2^{19}$.)
-@end tex
-@xref{Faces}.
+This glyph is simple.
@end table
- If a glyph code is greater than or equal to the length of the glyph
-table, that code is automatically simple.
-
@defun create-glyph string
@tindex create-glyph
This function returns a newly-allocated glyph code which is set up to
@end defopt
@defvar ring-bell-function
-@tindex ring-bell-function
If this is non-@code{nil}, it specifies how Emacs should ``ring the
bell.'' Its value should be a function of no arguments. If this is
non-@code{nil}, it takes precedence over the @code{visible-bell}
@item pc
Emacs is displaying using MS-DOS.
@item w32
-Emacs is displaying using Windows NT or Windows 9x.
+Emacs is displaying using Windows.
@item mac
Emacs is displaying using a Macintosh.
@item nil