@section Using Multiple Typefaces
@cindex faces
- When using Emacs with a window system, you can set up multiple
-styles of displaying characters. Each style is called a @dfn{face}.
-Each face can specify various attributes, such as the height, weight
-and slant of the characters, the foreground and background color, and
-underlining. But it does not have to specify all of them.
+ Emacs supports using multiple styles of displaying characters. Each
+style is called a @dfn{face}. Each face can specify various @dfn{face
+attributes}, such as the font family, the height, weight and slant of
+the characters, the foreground and background color, and underlining
+or overlining. A face does not have to specify all of these
+attributes; often it inherits many of them from another face.
+
+ On a window system, all the Emacs face attributes are meaningful.
+On a character terminal, only some of them work. Some character
+terminals support inverse video, bold, and underline attributes; some
+support colors. Character terminals generally do not support changing
+the height and width or the font family.
Features which rely on text in multiple faces (such as Font Lock mode)
will also work on non-windowed terminals that can display more than one
specifying the face or faces to use for it. The style of display used
for any given character is determined by combining the attributes of
all the applicable faces specified for that character. Any attribute
-that isn't specified by these faces is taken from the default face,
-which embodies the default settings of the frame itself.
+that isn't specified by these faces is taken from the @code{default} face,
+whose attributes reflect the default settings of the frame itself.
Enriched mode, the mode for editing formatted text, includes several
commands and menus for specifying faces for text in the buffer.
@findex set-face-background
To alter the appearance of a face, use the customization buffer.
@xref{Face Customization}. You can also use X resources to specify
-attributes of particular faces (@pxref{Resources X}). Alternatively,
+attributes of particular faces (@pxref{Resources}). Alternatively,
you can change the foreground and background colors of a specific face
with @kbd{M-x set-face-foreground} and @kbd{M-x set-face-background}.
These commands prompt in the minibuffer for a face name and a color
name, with completion, and then set that face to use the specified
-color.
+color. Changing the colors of the @code{default} face also changes
+the foreground and background colors on all frames, both existing and
+those to be created in the future. (You can also set foreground and
+background colors for the current frame only; see @ref{Frame
+Parameters}.)
Emacs 21 can correctly display variable-width fonts, but Emacs
commands that calculate width and indentation do not know how to
To see what faces are currently defined, and what they look like, type
@kbd{M-x list-faces-display}. It's possible for a given face to look
different in different frames; this command shows the appearance in the
-frame in which you type it. Here's a list of the standardly defined
+frame in which you type it. Here's a list of the standard defined
faces:
@table @code
the font are ignored in this case.
@item trailing-whitespace
The face for highlighting trailing whitespace when
-@code{show-trailing-whitespace} is non-nil.
+@code{show-trailing-whitespace} is non-nil; see @ref{Trailing Whitespace}.
@item variable-pitch
The basic variable-pitch face.
@end table
@c @w is used below to prevent a bad page-break.
@vindex font-lock-beginning-of-syntax-function
+@cindex incorrect fontification
+@cindex parenthesis in column zero and fontification
+@cindex brace in column zero and fontification
Comment and string fontification (or ``syntactic'' fontification)
relies on analysis of the syntactic structure of the buffer text. For
-the purposes of speed, some modes, including C mode and Lisp mode, rely on
-a special convention: an open-parenthesis in the leftmost column always
-defines the @w{beginning} of a defun, and is thus always outside any string
-or comment. (@xref{Defuns}.) If you don't follow this convention,
-then Font Lock mode can misfontify the text after an open-parenthesis in
+the sake of speed, some modes, including C mode and Lisp mode,
+rely on a special convention: an open-parenthesis or open-brace in the
+leftmost column always defines the @w{beginning} of a defun, and is
+thus always outside any string or comment. (@xref{Left Margin
+Paren}.) If you don't follow this convention, Font Lock mode can
+misfontify the text that follows an open-parenthesis or open-brace in
the leftmost column that is inside a string or comment.
@cindex slow display during scrolling
'(("\\<\\(FIXME\\):" 1 font-lock-warning-face t)))
@end example
+@findex font-lock-remove-keywords
+ To remove keywords from the font-lock highlighting patterns, use the
+function @code{font-lock-remove-keywords}.
+
+@cindex just-in-time (JIT) font-lock
+@cindex background syntax highlighting
+ Fontifying large buffers can take a long time. To avoid large
+delays when a file is visited, Emacs fontifies only the visible
+portion of a buffer. As you scroll through the buffer, each portion
+that becomes visible is fontified as soon as it is displayed. The
+parts of the buffer that are not displayed are fontified
+``stealthily'', in the background, i.e.@: when Emacs is idle. You can
+control this background fontification, called @dfn{Just-In-Time}, or
+@dfn{JIT} Font Lock, by customizing various options in the
+customization group @samp{jit-lock}. @xref{Specific Customization}.
+
@node Highlight Changes
@section Highlight Changes Mode
@findex unhighlight-regexp
Unhighlight @var{regexp} (@code{unhighlight-regexp}). You must enter
one of the regular expressions currently specified for highlighting.
-(You can use completion, or a menu, to enter one of them
+(You can use completion, or choose from a menu, to enter one of them
conveniently.)
@item C-x w l @var{regexp} @key{RET} @var{face} @key{RET}
@findex highlight-lines-matching-regexp
@cindex lines, highlighting
@cindex highlighting lines of text
-Highlight lines containing a match for @var{regexp}, using face
+Highlight entire lines containing a match for @var{regexp}, using face
@var{face} (@code{highlight-lines-matching-regexp}).
@item C-x w b
realizing it. In most cases, this @dfn{trailing whitespace} has no
effect, but there are special circumstances where it matters.
- You can make trailing whitespace visible on the screen by setting
-the variable @code{show-trailing-whitespace} to @code{t}. Then Emacs
-displays trailing whitespace in the face @code{trailing-whitespace}.
+ You can make trailing whitespace visible on the screen by setting the
+buffer-local variable @code{show-trailing-whitespace} to @code{t}. Then
+Emacs displays trailing whitespace in the face
+@code{trailing-whitespace}.
Trailing whitespace is defined as spaces or tabs at the end of a
line. But trailing whitespace is not displayed specially if point is
ugly while you are typing in new text, and the location of point is
enough in that case to show you that the spaces are present.)
+@findex delete-trailing-whitespace
+ To delete all trailing whitespace within the current buffer's
+restriction (@pxref{Narrowing}), type @kbd{M-x
+delete-trailing-whitespace @key{RET}}. (This command does not remove
+the form-feed characters.)
+
@vindex indicate-empty-lines
@vindex default-indicate-empty-lines
@cindex empty lines
@item C-v
Scroll forward (a windowful or a specified number of lines) (@code{scroll-up}).
@item @key{NEXT}
+@itemx @key{PAGEDOWN}
Likewise, scroll forward.
@item M-v
Scroll backward (@code{scroll-down}).
@item @key{PRIOR}
+@itemx @key{PAGEUP}
Likewise, scroll backward.
@item @var{arg} C-l
Scroll so point is on line @var{arg} (@code{recenter}).
@kindex M-v
@kindex NEXT
@kindex PRIOR
+@kindex PAGEDOWN
+@kindex PAGEUP
@findex scroll-up
@findex scroll-down
- The scrolling commands @kbd{C-v} and @kbd{M-v} let you move all the text
-in the window up or down a few lines. @kbd{C-v} (@code{scroll-up}) with an
-argument shows you that many more lines at the bottom of the window, moving
-the text and point up together as @kbd{C-l} might. @kbd{C-v} with a
-negative argument shows you more lines at the top of the window.
-@kbd{M-v} (@code{scroll-down}) is like @kbd{C-v}, but moves in the
-opposite direction. The function keys @key{NEXT} and @key{PRIOR} are
-equivalent to @kbd{C-v} and @kbd{M-v}.
-
- The names of scroll commands are based on the direction that the text
-moves in the window. Thus, the command to scroll forward is called
-@code{scroll-up} because it moves the text upward on the screen.
-
@vindex next-screen-context-lines
- To read the buffer a windowful at a time, use @kbd{C-v} with no argument.
-It takes the last two lines at the bottom of the window and puts them at
-the top, followed by nearly a whole windowful of lines not previously
-visible. If point was in the text scrolled off the top, it moves to the
-new top of the window. @kbd{M-v} with no argument moves backward with
-overlap similarly. The number of lines of overlap across a @kbd{C-v} or
-@kbd{M-v} is controlled by the variable @code{next-screen-context-lines}; by
-default, it is 2.
+ To read the buffer a windowful at a time, use @kbd{C-v}
+(@code{scroll-up}) with no argument. This scrolls forward by nearly
+the whole window height. The effect is to take the two lines at the
+bottom of the window and put them at the top, followed by nearly a
+whole windowful of lines that were not previously visible. If point
+was in the text that scrolled off the top, it ends up at the new top
+of the window.
+
+ @kbd{M-v} (@code{scroll-down}) with no argument scrolls backward in
+a similar way, also with overlap. The number of lines of overlap
+across a @kbd{C-v} or @kbd{M-v} is controlled by the variable
+@code{next-screen-context-lines}; by default, it is 2. The function
+keys @key{NEXT} and @key{PRIOR}, or @key{PAGEDOWN} and @key{PAGEUP},
+are equivalent to @kbd{C-v} and @kbd{M-v}.
+
+ The commands @kbd{C-v} and @kbd{M-v} with a numeric argument scroll
+the text in the selected window up or down a few lines. @kbd{C-v}
+with an argument moves the text and point up, together, that many
+lines; it brings the same number of new lines into view at the bottom
+of the window. @kbd{M-v} with numeric argument scrolls the text
+downward, bringing that many new lines into view at the top of the
+window. @kbd{C-v} with a negative argument is like @kbd{M-v} and vice
+versa.
+
+ The names of scroll commands are based on the direction that the
+text moves in the window. Thus, the command to scroll forward is
+called @code{scroll-up} because it moves the text upward on the
+screen. The keys @key{PAGEDOWN} and @key{PAGEUP} derive their names
+and customary meanings from a different convention that developed
+elsewhere; hence the strange result that @key{PAGEDOWN} runs
+@code{scroll-up}.
@vindex scroll-preserve-screen-position
Some users like the full-screen scroll commands to keep point at the
rather, the text and point move rigidly on the screen. @kbd{C-l} with a
negative argument puts point that many lines from the bottom of the window.
For example, @kbd{C-u - 1 C-l} puts point on the bottom line, and @kbd{C-u
-- 5 C-l} puts it five lines from the bottom. Just @kbd{C-u} as argument,
-as in @kbd{C-u C-l}, scrolls point to the center of the selected window.
+- 5 C-l} puts it five lines from the bottom. @kbd{C-u C-l} scrolls to put
+point at the center (vertically) of the selected window.
@kindex C-M-l
@findex reposition-window
entire current defun onto the screen if possible.
@vindex scroll-conservatively
- Scrolling happens automatically if point has moved out of the visible
-portion of the text when it is time to display. Normally, automatic
-scrolling centers point vertically within the window. However, if you
-set @code{scroll-conservatively} to a small number @var{n}, then if you
-move point just a little off the screen---less than @var{n} lines---then
-Emacs scrolls the text just far enough to bring point back on screen.
-By default, @code{scroll-conservatively} is 0.
+ Scrolling happens automatically when point moves out of the visible
+portion of the text. Normally, automatic scrolling centers point
+vertically within the window. However, if you set
+@code{scroll-conservatively} to a small number @var{n}, then if you
+move point just a little off the screen---less than @var{n}
+lines---then Emacs scrolls the text just far enough to bring point
+back on screen. By default, @code{scroll-conservatively} is 0.
@cindex aggressive scrolling
@vindex scroll-up-aggressively
@dfn{Horizontal scrolling} means shifting all the lines sideways
within a window---so that some of the text near the left margin is not
-displayed at all. Emacs does this automatically, in any window that
+displayed at all. Emacs does this automatically in any window that
uses line truncation rather than continuation: whenever point moves
off the left or right edge of the screen, Emacs scrolls the buffer
horizontally to make point visible.
indicate what it is. @xref{Minor Modes}, for more information about
minor modes and about how to use this command.
+@cindex narrowing, and line number display
+ If you have narrowed the buffer (@pxref{Narrowing}), the displayed
+line number is relative to the accessible portion of the buffer.
+
@vindex line-number-display-limit
If the buffer is very large (larger than the value of
@code{line-number-display-limit}), then the line number doesn't appear.
Emacs doesn't compute the line number when the buffer is large, because
-that would be too slow. Set it to @code{nil} to remove the limit. If
-you have narrowed the buffer (@pxref{Narrowing}), the displayed line
-number is relative to the accessible portion of the buffer.
+that would be too slow. Set it to @code{nil} to remove the limit.
+
+@vindex line-number-display-limit-width
+ Line-number computation can also be slow if the lines in the buffer
+are too long. For this reason, Emacs normally doesn't display line
+numbers if the average width, in characters, of lines near point is
+larger than the value of the variable
+@code{line-number-display-limit-width}. The default value is 200
+characters.
@cindex Column Number mode
@cindex mode, Column Number
line. You can customize @code{display-time-mail-face} to make the mail
indicator prominent.
-@cindex mode line, 3D appearence
+@cindex mode line, 3D appearance
@cindex attributes of mode line, changing
@cindex non-integral number of lines in a window
- By default, the mode line is drawn on graphics displays as a 3D
-released button. Depending on the font used for the mode line's text,
-this might make the mode line use more space than a text line in a
-window, and cause the last line of the window be partially obscured.
-That is, the window displays a non-integral number of text lines. If
-you don't like this effect, you can disable the 3D appearence of the
-mode line by customizing the attributes of the @code{mode-line} face in
-your @file{.emacs} init file, like this:
+ By default, the mode line is drawn on graphics displays with
+3D-style highlighting, like that of a button when it is not being
+pressed. If you don't like this effect, you can disable the 3D
+highlighting of the mode line, by customizing the attributes of the
+@code{mode-line} face in your @file{.emacs} init file, like this:
@example
- (set-face-attribute 'mode-line nil :box nil)
+(set-face-attribute 'mode-line nil :box nil)
@end example
@noindent
-Alternatively, you could turn off the box attribute in your
+Alternatively, you can turn off the box attribute in your
@file{.Xdefaults} file:
@example
- Emacs.mode-line.AttributeBox: off
+Emacs.mode-line.AttributeBox: off
@end example
@node Text Display
octal escape sequences; thus, character code 0230 (octal) is displayed
as @samp{\230}. The display of character codes 0240 through 0377
(octal) may be either as escape sequences or as graphics. They do not
-normally occur in multibyte buffers but if they do, they are displayed
+normally occur in multibyte buffers, but if they do, they are displayed
as Latin-1 graphics. In unibyte mode, if you enable European display
they are displayed using their graphics (assuming your terminal supports
them), otherwise as escape sequences. @xref{Single-Byte Character
The variable @code{mode-line-inverse-video} is an obsolete way of
controlling whether the mode line is displayed in inverse video; the
preferred way of doing this is to change the @code{mode-line} face.
-@xref{Mode Line}. If you specify the foreground color for the
-@code{mode-line} face, and @code{mode-line-inverse-video} is
-non-@code{nil}, then the default background color for that face is the
-usual foreground color. @xref{Faces}.
+@xref{Mode Line}. However, if @code{mode-line-inverse-video} has a
+value of @code{nil}, then the @code{mode-line} face will be ignored,
+and mode-lines will be drawn using the default text face.
+@xref{Faces}.
@vindex inverse-video
If the variable @code{inverse-video} is non-@code{nil}, Emacs attempts
amount of time Emacs must remain busy before the busy indicator is
displayed, by setting the variable @code{hourglass-delay}.
+@findex tty-suppress-bold-inverse-default-colors
+ On some text-only terminals, bold face and inverse video together
+result in text that is hard to read. Call the function
+@code{tty-suppress-bold-inverse-default-colors} with a non-@code{nil}
+argument to suppress the effect of bold-face in this case.
+
@node Cursor Display
@section Displaying the Cursor
@findex hl-line-mode
+@cindex highlight current line
@findex blink-cursor-mode
@cindex cursor, locating visually
@cindex cursor, blinking
There are a number of ways to customize the display of the cursor.
-@kbd{M-x hl-line-mode} enables or disables a global minor mode which
+@kbd{M-x hl-line-mode} enables or disables a minor mode which
highlights the line containing point. On window systems, the command
@kbd{M-x blink-cursor-mode} turns on or off the blinking of the
cursor. (On terminals, the terminal itself blinks the cursor, and