@c This is part of the Emacs manual.
-@c Copyright (C) 1985, 86, 87, 93, 94, 95, 1997, 2000, 2001
+@c Copyright (C) 1985, 86, 87, 93, 94, 95, 1997, 2000, 2001, 2002
@c Free Software Foundation, Inc.
@c See file emacs.texi for copying conditions.
@node Display, Search, Registers, Top
* Font Lock:: Minor mode for syntactic highlighting using faces.
* Highlight Changes:: Using colors to show where you changed the buffer.
* Highlight Interactively:: Tell Emacs what text to highlight.
-* Trailing Whitespace:: Showing possibly-spurious trailing whitespace.
* Scrolling:: Moving text up and down in a window.
* Horizontal Scrolling:: Moving text left and right in a window.
+* Fringes:: Enabling or disabling window fringes.
+* Useless Whitespace:: Showing possibly-spurious trailing whitespace.
* Follow Mode:: Follow mode lets two windows scroll as one.
* Selective Display:: Hiding lines with lots of indentation.
* Optional Mode Line:: Optional mode line display features.
@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
@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
@item default
This face is used for ordinary text that doesn't specify any other face.
@item mode-line
-This face is used for mode lines. By default, it's drawn with shadows
-for a ``raised'' effect on window systems, and drawn as the inverse of
-the default face on non-windowed terminals. @xref{Display Custom}.
+This face is used for the mode line of the currently selected window.
+By default, it's drawn with shadows for a ``raised'' effect on window
+systems, and drawn as the inverse of the default face on non-windowed
+terminals. @xref{Display Custom}.
+@item mode-line-inactive
+Like @code{mode-line}, but used for mode lines of the windows other
+than the selected one (if @code{mode-line-in-non-selected-windows} is
+non-@code{nil}). This face inherits from @code{mode-line}, so changes
+in that face affect mode lines in all windows.
@item header-line
Similar to @code{mode-line} for a window's header line. Most modes
don't use the header line, but the Info mode does.
+@item minibuffer-prompt
+This face is used for the prompt strings displayed in the minibuffer.
@item highlight
This face is used for highlighting portions of text, in various modes.
For example, mouse-sensitive text is highlighted using this face.
the font are ignored in this case.
@item trailing-whitespace
The face for highlighting trailing whitespace when
-@code{show-trailing-whitespace} is non-nil; see @ref{Trailing Whitespace}.
+@code{show-trailing-whitespace} is non-@code{nil}; see @ref{Useless
+Whitespace}.
@item variable-pitch
The basic variable-pitch face.
@end table
@cindex mode, Font Lock
@cindex syntax highlighting and coloring
- Font Lock mode is a minor mode, always local to a particular
-buffer, which highlights (or ``fontifies'') using various faces
-according to the syntax of the text you are editing. It can
-recognize comments and strings in most languages; in several
-languages, it can also recognize and properly highlight various other
-important constructs---for example, names of functions being defined
-or reserved keywords.
+ Font Lock mode is a minor mode, always local to a particular buffer,
+which highlights (or ``fontifies'') using various faces according to
+the syntax of the text you are editing. It can recognize comments and
+strings in most languages; in several languages, it can also recognize
+and properly highlight various other important constructs---for
+example, names of functions being defined or reserved keywords.
+Some special modes, such as Occur mode and Info mode, have completely
+specialized ways of assigning fonts for Font Lock mode.
@findex font-lock-mode
@findex turn-on-font-lock
@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 sake of speed, some modes, including C mode and Lisp mode,
'(("\\<\\(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
@code{hi-lock-exclude-modes}.
@end table
-@node Trailing Whitespace
-@section Trailing Whitespace
-
-@cindex trailing whitespace
-@cindex whitespace, trailing
-@vindex show-trailing-whitespace
- It is easy to leave unnecessary spaces at the end of a line without
-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
-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
-at the end of the line containing the whitespace. (Doing that looks
-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.)
-
-@vindex indicate-empty-lines
-@vindex default-indicate-empty-lines
-@cindex empty lines
- Emacs can indicate empty lines at the end of the buffer with a
-special bitmap on the left fringe of the window. To enable this
-feature, set the buffer-local variable @code{indicate-empty-lines} to
-a non-@code{nil} value. The default value of this variable is
-controlled by the variable @code{default-indicate-empty-lines};
-by setting that variable, you can enable or disable this feature
-for all new buffers.
-
@node Scrolling
@section Scrolling
@cindex aggressive scrolling
@vindex scroll-up-aggressively
-@vindex scroll-down-aggressively
+@vindex scroll-down-aggressively
When the window does scroll by a longer distance, you can control
how aggressively it scrolls, by setting the variables
@code{scroll-up-aggressively} and @code{scroll-down-aggressively}.
to scroll the window, but never farther to the right than the amount
you previously set by @code{scroll-left}.
-@vindex automatic-hscrolling
+@vindex hscroll-margin
+ The value of the variable @code{hscroll-margin} controls how close
+to the window's edges point is allowed to get before the window will
+be automatically scrolled. It is measured in columns. If the value
+is 5, then moving point within 5 columns of the edge causes horizontal
+scrolling away from that edge.
+
+@vindex hscroll-step
+ The variable @code{hscroll-step} determines how many columns to
+scroll the window when point gets too close to the edge. If it's
+zero, horizontal scrolling centers point horizontally within the
+window. If it's a positive integer, it specifies the number of
+columns to scroll by. If it's a floating-point number, it specifies
+the fraction of the window's width to scroll by. The default is zero.
+
+@vindex auto-hscroll-mode
To disable automatic horizontal scrolling, set the variable
-@code{automatic-hscrolling} to @code{nil}.
+@code{auto-hscroll-mode} to @code{nil}.
+
+@node Fringes
+@section Window Fringes
+@cindex fringes
+
+ On a graphical display, each Emacs window normally has narrow
+@dfn{fringes} on the left and right edges. The fringes display
+indications about the text in the window.
+
+ The most common use of the fringes is to indicate a continuation
+line, when one line of text is split into multiple lines on the
+screen. The left fringe shows a curving arrow for each screen line
+except the first, indicating that ``this is not the real beginning.''
+The right fringe shows a curving arrow for each screen line except the
+last, indicating that ``this is not the real end.''
+
+ The fringes indicate line truncation with short horizontal arrows
+meaning ``there's more text on this line which is scrolled
+horizontally out of view;'' clicking the mouse on one of the arrows
+scrolls the display horizontally in the direction of the arrow. The
+fringes also indicate other things such as empty lines, or where a
+program you are debugging is executing (@pxref{Debuggers}).
+
+@findex set-fringe-style
+@findex fringe-mode
+ You can enable and disable the fringes for all frames using
+@kbd{M-x fringe-mode}. To enable and disable the fringes
+for the selected frame, use @kbd{M-x set-fringe-style}.
+
+@node Useless Whitespace
+@section Useless Whitespace
+
+@cindex trailing whitespace
+@cindex whitespace, trailing
+@vindex show-trailing-whitespace
+ It is easy to leave unnecessary spaces at the end of a line, or
+empty lines at the end of a file, without 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 at the end of a line 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}.
+
+ This feature does not apply when point is at the end of the line
+containing the whitespace. Strictly speaking, that is ``trailing
+whitespace'' nonetheless, but displaying it specially in that case
+looks ugly while you are typing in new text. In this special case,
+the location of point is enough to show you that the spaces are
+present.
+
+@findex delete-trailing-whitespace
+ To delete all trailing whitespace within the current buffer's
+accessible portion (@pxref{Narrowing}), type @kbd{M-x
+delete-trailing-whitespace @key{RET}}. (This command does not remove
+the form-feed characters.)
+
+@vindex indicate-unused-lines
+@vindex default-indicate-empty-lines
+@cindex unused lines
+@cindex fringes, and unused line indication
+ Emacs can indicate unused lines at the end of the window with a
+small image in the left fringe (@pxref{Fringes}). The image appears
+for window lines that do not correspond to any buffer text. Blank
+lines at the end of the buffer then stand out because they do not have
+this image in the fringe.
+
+ To enable this feature, set the buffer-local variable
+@code{indicate-unused-lines} to a non-@code{nil} value. The default
+value of this variable is controlled by the variable
+@code{default-indicate-unused-lines}; by setting that variable, you
+can enable or disable this feature for all new buffers. (This feature
+currently doesn't work on character terminals.)
@node Follow Mode
@section Follow Mode
@cindex mail (on mode line)
@vindex display-time-use-mail-icon
@vindex display-time-mail-face
+@vindex display-time-mail-file
+@vindex display-time-mail-directory
The word @samp{Mail} appears after the load level if there is mail
for you that you have not read yet. On a graphical display you can use
an icon instead of @samp{Mail} by customizing
@code{display-time-use-mail-icon}; this may save some space on the mode
line. You can customize @code{display-time-mail-face} to make the mail
-indicator prominent.
+indicator prominent. Use @code{display-time-mail-file} to specify
+the mail file to check, or set @code{display-time-mail-directory}
+to specify the directory to check for incoming mail (any nonempty regular
+file in the directory is considered as ``newly arrived mail'').
-@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 with
Emacs.mode-line.AttributeBox: off
@end example
+@cindex non-selected windows, mode line appearance
+ By default, the mode line of nonselected windows is displayed in a
+different face, called @code{mode-line-inactive}. Only the selected
+window is displayed in the @code{mode-line} face. This helps show
+which window is selected. When the minibuffer is selected, since
+it has no mode line, the window from which you activated the minibuffer
+has its mode line displayed using @code{mode-line}; as a result,
+ordinary entry to the minibuffer does not change any mode lines.
+
+@vindex mode-line-in-non-selected-windows
+ You can disable use of @code{mode-line-inactive} by setting variable
+@code{mode-line-in-non-selected-windows} to @code{nil}; then all mode
+lines are displayed in the @code{mode-line} face.
+
@node Text Display
@section How Text Is Displayed
@cindex characters (in text)
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
+@vindex blink-cursor-alist
@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
-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
-Emacs has no control over it.)
-
You can customize the cursor's color, and whether it blinks, using
-the @code{cursor} Custom group (@pxref{Easy Customization}).
+the @code{cursor} Custom group (@pxref{Easy Customization}). On
+graphical terminals, the command @kbd{M-x blink-cursor-mode} enables
+or disables the blinking of the cursor. (On text terminals, the
+terminal itself blinks the cursor, and Emacs has no control over it.)
+You can control how the cursor appears when it blinks off by setting
+the variable @code{blink-cursor-alist}.
+
+@cindex cursor in non-selected windows
+@vindex cursor-in-non-selected-windows
+ Normally, the cursor appears in non-selected windows in the ``off''
+state, with the same appearance as when the blinking cursor blinks
+``off''. For a box cursor, this is a hollow box; for a bar cursor,
+this is a thinner bar. To turn off cursors in non-selected windows,
+customize the option @code{cursor-in-non-selected-windows} and assign
+it a @code{nil} value.
@vindex x-stretch-cursor
@cindex wide block cursor
- When displaying on a window system, Emacs can optionally draw the
-block cursor as wide as the character under the cursor---for example,
-if the cursor is on a tab character, it would cover the full width
-occupied by that tab character. To enable this feature, set the
-variable @code{x-stretch-cursor} to a non-@code{nil} value.
+ On graphical terminals, Emacs can optionally draw the block cursor
+as wide as the character under the cursor---for example, if the cursor
+is on a tab character, it would cover the full width occupied by that
+tab character. To enable this feature, set the variable
+@code{x-stretch-cursor} to a non-@code{nil} value.
-@cindex cursor in non-selected windows
-@vindex cursor-in-non-selected-windows
- Normally, the cursor in non-selected windows is shown as a hollow box.
-To turn off cursor display in non-selected windows, customize the option
-@code{cursor-in-non-selected-windows} to assign it a @code{nil} value.
+@findex hl-line-mode
+@findex global-hl-line-mode
+@cindex highlight current line
+ If you find it hard to see the cursor, you might like HL Line mode,
+a minor mode that highlights the line containing point. Use @kbd{M-x
+hl-line-mode} to enable or disable it in the current buffer. @kbd{M-x
+global-hl-line-mode} enables or disables the same mode globally.