@c This is part of the Emacs manual.
-@c Copyright (C) 1985-1987, 1993-1995, 1997, 2000-2011
+@c Copyright (C) 1985-1987, 1993-1995, 1997, 2000-2012
@c Free Software Foundation, Inc.
@c See file emacs.texi for copying conditions.
-@node Display, Search, Registers, Top
+@node Display
@chapter Controlling the Display
Since only part of a large buffer fits in the window, Emacs has to
* View Mode:: Viewing read-only buffers.
* Follow Mode:: Follow mode lets two windows scroll as one.
* Faces:: How to change the display style using faces.
-* Standard Faces:: Emacs' predefined faces.
+* Colors:: Specifying colors for faces.
+* Standard Faces:: The main predefined faces.
* Text Scale:: Increasing or decreasing text size in a buffer.
* Font Lock:: Minor mode for syntactic highlighting using faces.
* Highlight Interactively:: Tell Emacs what text to highlight.
* Fringes:: Enabling or disabling window fringes.
* Displaying Boundaries:: Displaying top and bottom of the buffer.
-* Useless Whitespace:: Showing possibly-spurious trailing whitespace.
+* Useless Whitespace:: Showing possibly spurious trailing whitespace.
* Selective Display:: Hiding lines with lots of indentation.
* Optional Mode Line:: Optional mode line display features.
* Text Display:: How text characters are normally displayed.
These two variables are ignored if either @code{scroll-step} or
@code{scroll-conservatively} are set to a non-zero value.
- Note that @code{scroll-margin}, described below, limits the amount
-of scrolling so as to put point outside of the top or bottom margin,
-even if aggressive scrolling specifies a fraction @var{f} that is
-larger than the window portion between the top and the bottom margins.
-
@vindex scroll-margin
The variable @code{scroll-margin} restricts how close point can come
-to the top or bottom of a window. Its value is a number of screen
+to the top or bottom of a window (even if aggressive scrolling
+specifies a fraction @var{f} that is larger than the window portion
+between the top and the bottom margins). Its value is a number of screen
lines; if point comes within that many lines of the top or bottom of
the window, Emacs performs automatic scrolling. By default,
@code{scroll-margin} is 0.
screen. To disable automatic horizontal scrolling, set the variable
@code{auto-hscroll-mode} to @code{nil}. Note that when the automatic
horizontal scrolling is turned off, if point moves off the edge of the
-screen, the cursor disappears to indicate that. (On text-only
-terminals, the cursor is left at the edge instead.)
+screen, the cursor disappears to indicate that. (On text terminals,
+the cursor is left at the edge instead.)
@vindex hscroll-margin
The variable @code{hscroll-margin} controls how close point can get
@cindex synchronizing windows
@dfn{Follow mode} is a minor mode that makes two windows, both
-showing the same buffer, scroll as a single tall ``virtual window.''
+showing the same buffer, scroll as a single tall ``virtual window''.
To use Follow mode, go to a frame with just one window, split it into
two side-by-side windows using @kbd{C-x 3}, and then type @kbd{M-x
follow-mode}. From then on, you can edit the buffer in either of the
To turn off Follow mode, type @kbd{M-x follow-mode} a second time.
@node Faces
-@section Faces: Controlling Text Display Style
+@section Text Faces
@cindex faces
Emacs can display text in several different styles, called
matching that regular expression (@pxref{Regexps}).
It's possible for a given face to look different in different
-frames. For instance, some text-only terminals do not support all
-face attributes, particularly font, height, and width, and some
-support a limited range of colors. The @code{list-faces-display}
-command shows the appearance for the selected frame.
+frames. For instance, some text terminals do not support all face
+attributes, particularly font, height, and width, and some support a
+limited range of colors.
-@cindex face colors, setting
@cindex background color
@cindex default face
You can customize a face to alter its appearance, and save those
changes for future Emacs sessions. @xref{Face Customization}. A face
does not have to specify every single attribute; often it inherits
most attributes from another face. Any ultimately unspecified
-attribute is taken from a face named @code{default}, whose attributes
-are all specified. The @code{default} face is the default for
-displaying text, and its background color is also used as the frame's
-background color.
+attribute is taken from the face named @code{default}.
+
+ The @code{default} face is the default for displaying text, and all
+of its attributes are specified. Its background color is also used as
+the frame's background color. @xref{Colors}.
+
+@cindex cursor face
+ Another special face is the @code{cursor} face. On graphical
+displays, the background color of this face is used to draw the text
+cursor. None of the other attributes of this face have any effect;
+the foreground color for text under the cursor is taken from the
+background color of the underlying text. On text terminals, the
+appearance of the text cursor is determined by the terminal, not by
+the @code{cursor} face.
You can also use X resources to specify attributes of any particular
face. @xref{Resources}.
+ Emacs can display variable-width fonts, but some Emacs commands,
+particularly indentation commands, do not account for variable
+character display widths. Therefore, we recommend not using
+variable-width fonts for most faces, particularly those assigned by
+Font Lock mode.
+
+@node Colors
+@section Colors for Faces
+@cindex color name
+@cindex RGB triplet
+
+ Faces can have various foreground and background colors. When you
+specify a color for a face---for instance, when customizing the face
+(@pxref{Face Customization})---you can use either a @dfn{color name}
+or an @dfn{RGB triplet}.
+
+@findex list-colors-display
+@vindex list-colors-sort
+ A color name is a pre-defined name, such as @samp{dark orange} or
+@samp{medium sea green}. To view a list of color names, type @kbd{M-x
+list-colors-display}. To control the order in which colors are shown,
+customize @code{list-colors-sort}. If you run this command on a
+graphical display, it shows the full range of color names known to
+Emacs (these are the standard X11 color names, defined in X's
+@file{rgb.txt} file). If you run the command on a text terminal, it
+shows only a small subset of colors that can be safely displayed on
+such terminals. However, Emacs understands X11 color names even on
+text terminals; if a face is given a color specified by an X11 color
+name, it is displayed using the closest-matching terminal color.
+
+ An RGB triplet is a string of the form @samp{#RRGGBB}. Each of the
+R, G, and B components is a hexadecimal number specifying the
+component's relative intensity, one to four digits long (usually two
+digits are used). The components must have the same number of digits.
+For hexadecimal values A to F, either upper or lower case are
+acceptable.
+
+ The @kbd{M-x list-colors-display} command also shows the equivalent
+RGB triplet for each named color. For instance, @samp{medium sea
+green} is equivalent to @samp{#3CB371}.
+
+@cindex face colors, setting
@findex set-face-foreground
@findex set-face-background
- You can also change the foreground and background colors of a 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 (@pxref{Face Customization}, for information about color names).
+ You can change the foreground and background colors of a 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,
+with completion, and then set that face to use the specified color.
They affect the face colors on all frames, but their effects do not
persist for future Emacs sessions, unlike using the customization
buffer or X resources. You can also use frame parameters to set
-foreground and background colors for a specific frame; see @ref{Frame
+foreground and background colors for a specific frame; @xref{Frame
Parameters}.
- Emacs can display variable-width fonts, but some Emacs commands,
-particularly indentation commands, do not account for variable
-character display widths. Therefore, we recommend not using
-variable-width fonts for most faces, particularly those assigned by
-Font Lock mode.
-
@node Standard Faces
@section Standard Faces
Most windows do not have a header line---only some special modes, such
Info mode, create one.
@item vertical-border
-This face is used for the vertical divider between windows on
-text-only terminals.
+This face is used for the vertical divider between windows on text
+terminals.
@item minibuffer-prompt
@cindex @code{minibuffer-prompt} face
@vindex minibuffer-prompt-properties
@end table
The following faces likewise control the appearance of parts of the
-Emacs frame, but only on text-only terminals, or when Emacs is built
-on X with no toolkit support. (For all other cases, the appearance of
-the respective frame elements is determined by system-wide settings.)
+Emacs frame, but only on text terminals, or when Emacs is built on X
+with no toolkit support. (For all other cases, the appearance of the
+respective frame elements is determined by system-wide settings.)
@table @code
@item scroll-bar
@findex global-font-lock-mode
@vindex global-font-lock-mode
- To toggle Font Lock mode in all buffers, type @kbd{M-x
-global-font-lock-mode}. To impose this setting for future Emacs
-sessions, customize the variable @code{global-font-lock-mode}
-(@pxref{Easy Customization}), or add the following line to your init
-file:
+ Type @kbd{M-x global-font-lock-mode} to toggle Font Lock mode in all
+buffers. To impose this setting for future Emacs sessions, customize
+the variable @code{global-font-lock-mode} (@pxref{Easy
+Customization}), or add the following line to your init file:
@example
(global-font-lock-mode 0)
line (@pxref{Continuation Lines}). When one line of text is split
into multiple screen lines, 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
+real beginning''. The right fringe shows a curving arrow for each
screen line except the last, indicating that ``this is not the real
-end.'' If the line's direction is right-to-left (@pxref{Bidirectional
+end''. If the line's direction is right-to-left (@pxref{Bidirectional
Editing}), the meanings of the curving arrows in the fringes are
swapped.
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
+horizontally out of view''. Clicking the mouse on one of the arrows
scrolls the display horizontally in the direction of the arrow.
The fringes can also indicate other things, such as buffer
@cindex fringes, and unused line indication
On graphical displays, 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-empty-lines} to
-a non-@code{nil} value. You can enable or disable this feature for
-all new buffers by setting the default value of this variable,
-e.g.@:@code{(setq-default indicate-empty-lines t)}.
+The image appears for screen lines that do not correspond to any
+buffer text, so blank lines at the end of the buffer stand out because
+they lack this image. To enable this feature, set the buffer-local
+variable @code{indicate-empty-lines} to a non-@code{nil} value. You
+can enable or disable this feature for all new buffers by setting the
+default value of this variable, e.g.@: @code{(setq-default
+indicate-empty-lines t)}.
+
+@cindex Whitespace mode
+@cindex mode, Whitespace
+@findex whitespace-mode
+@vindex whitespace-style
+ Whitespace mode is a buffer-local minor mode that lets you
+``visualize'' many kinds of whitespace in the buffer, by either
+drawing the whitespace characters with a special face or displaying
+them as special glyphs. To toggle this mode, type @kbd{M-x
+whitespace-mode}. The kinds of whitespace visualized are determined
+by the list variable @code{whitespace-style}. Here is a partial list
+of possible elements (see the variable's documentation for the full
+list):
+
+@table @code
+@item face
+Enable all visualizations which use special faces. This element has a
+special meaning: if it is absent from the list, none of the other
+visualizations take effect except @code{space-mark}, @code{tab-mark},
+and @code{newline-mark}.
+
+@item trailing
+Highlight trailing whitespace.
+
+@item tabs
+Highlight tab characters.
+
+@item spaces
+Highlight space and non-breaking space characters.
+
+@item lines
+@vindex whitespace-line-column
+Highlight lines longer than 80 lines. To change the column limit,
+customize the variable @code{whitespace-line-column}.
+
+@item newline
+Highlight newlines.
+
+@item empty
+Highlight empty lines.
+
+@item space-mark
+Draw space and non-breaking characters with a special glyph.
+
+@item tab-mark
+Draw tab characters with a special glyph.
+
+@item newline-mark
+Draw newline characters with a special glyph.
+@end table
@node Selective Display
@section Selective Display
Some non-@acronym{ASCII} characters have the same appearance as an
@acronym{ASCII} space or hyphen (minus) character. Such characters
can cause problems if they are entered into a buffer without your
-realization, e.g. by yanking; for instance, source code compilers
+realization, e.g.@: by yanking; for instance, source code compilers
typically do not treat non-@acronym{ASCII} spaces as whitespace
characters. To deal with this problem, Emacs displays such characters
specially: it displays @code{U+00A0} (no-break space) with the
Emacs can display long lines by @dfn{truncation}. This means that all
the characters that do not fit in the width of the screen or window do
not appear at all. On graphical displays, a small straight arrow in
-the fringe indicates truncation at either end of the line. On
-text-only terminals, this is indicated with @samp{$} signs in the
-leftmost and/or rightmost columns.
+the fringe indicates truncation at either end of the line. On text
+terminals, this is indicated with @samp{$} signs in the leftmost
+and/or rightmost columns.
@vindex truncate-lines
@findex toggle-truncate-lines
itself, in pixels; the default is 2.
@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
+ On some text 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.
HCoop / bpt / emacs.git / blobdiff