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J. Controlling the Display

Since only part of a large buffer fits in the window, Emacs tries to show a part that is likely to be interesting. Display-control commands allow you to specify which part of the text you want to see, and how to display it.

J.1 Using Multiple Typefaces  How to change the display style using faces.
J.2 Font Lock mode  Minor mode for syntactic highlighting using faces.
J.3 Highlight Changes Mode  Using colors to show where you changed the buffer.
J.4 Interactive Highlighting by Matching  Tell Emacs what text to highlight.
J.5 Trailing Whitespace  Showing possibly-spurious trailing whitespace.
J.6 Scrolling  Moving text up and down in a window.
J.7 Horizontal Scrolling  Moving text left and right in a window.
J.8 Follow Mode  Follow mode lets two windows scroll as one.
J.9 Selective Display  Hiding lines with lots of indentation.
J.10 Optional Mode Line Features  Optional mode line display features.
J.11 How Text Is Displayed  How text characters are normally displayed.
J.12 Customization of Display  Information on variables for customizing display.
J.13 Displaying the Cursor  Features for displaying the cursor.

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J.1 Using Multiple Typefaces

When using Emacs with a window system, you can set up multiple styles of displaying characters. Each style is called a 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 on a character terminal supports only part of face attributes. Which attributes are supported depends on your display type, but many displays support inverse video, bold, and underline attributes, and some support colors.

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 face, whether by colors or underlining and emboldening. This includes the console on GNU/Linux, an xterm which supports colors, the MS-DOS display (see section AH. Emacs and MS-DOS), and the MS-Windows version invoked with the `-nw' option. Emacs determines automatically whether the terminal has this capability.

You control the appearance of a part of the text in the buffer by 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, 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. See section T.11.4 Faces in Formatted Text, for how to specify the font for text in the buffer. See section T.11.5 Colors in Formatted Text, for how to specify the foreground and background color.

To alter the appearance of a face, use the customization buffer. See section AD.2.2.3 Customizing Faces. You can also use X resources to specify attributes of particular faces (see section AE.13 X Resources). Alternatively, you can change the foreground and background colors of a specific face with M-x set-face-foreground and 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. Changing the colors of the 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 P.12 Setting Frame Parameters.)

Emacs 21 can correctly display variable-width fonts, but Emacs commands that calculate width and indentation do not know how to calculate variable widths. This can sometimes lead to incorrect results when you use variable-width fonts. In particular, indentation commands can give inconsistent results, so we recommend you avoid variable-width fonts for editing program source code. Filling will sometimes make lines too long or too short. We plan to address these issues in future Emacs versions.

To see what faces are currently defined, and what they look like, type 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 standard defined faces:

This face is used for ordinary text that doesn't specify any other face.
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. See section J.12 Customization of Display.
Similar to mode-line for a window's header line. Most modes don't use the header line, but the Info mode does.
This face is used for highlighting portions of text, in various modes. For example, mouse-sensitive text is highlighted using this face.
This face is used for highlighting Isearch matches.
This face is used for lazy highlighting of Isearch matches other than the current one.
This face is used for displaying a selected region (when Transient Mark mode is enabled--see below).
This face is used for displaying a secondary X selection (see section P.2 Secondary Selection).
This face uses a bold variant of the default font, if it has one.
This face uses an italic variant of the default font, if it has one.
This face uses a bold italic variant of the default font, if it has one.
This face underlines text.
The basic fixed-pitch face.
The face for the fringes to the left and right of windows on graphic displays. (The fringes are the narrow portions of the Emacs frame between the text area and the window's right and left borders.)
This face determines the visual appearance of the scroll bar.
This face determines the color of the frame border.
This face determines the color of the cursor.
This face determines the color of the mouse pointer.
This is the basic tool-bar face. No text appears in the tool bar, but the colors of this face affect the appearance of tool bar icons.
This face is used for tooltips.
This face determines the colors and font of Emacs's menus. Setting the font of LessTif/Motif menus is currently not supported; attempts to set the font are ignored in this case.
The face for highlighting trailing whitespace when show-trailing-whitespace is non-nil; see J.5 Trailing Whitespace.
The basic variable-pitch face.

When Transient Mark mode is enabled, the text of the region is highlighted when the mark is active. This uses the face named region; you can control the style of highlighting by changing the style of this face (see section AD.2.2.3 Customizing Faces). See section H.2 Transient Mark Mode, for more information about Transient Mark mode and activation and deactivation of the mark.

One easy way to use faces is to turn on Font Lock mode. This minor mode, which is always local to a particular buffer, arranges to choose 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. See section J.2 Font Lock mode, for more information about Font Lock mode and syntactic highlighting.

You can print out the buffer with the highlighting that appears on your screen using the command ps-print-buffer-with-faces. See section AC.19 PostScript Hardcopy.

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J.2 Font Lock mode

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.

The command M-x font-lock-mode turns Font Lock mode on or off according to the argument, and toggles the mode when it has no argument. The function turn-on-font-lock unconditionally enables Font Lock mode. This is useful in mode-hook functions. For example, to enable Font Lock mode whenever you edit a C file, you can do this:

(add-hook 'c-mode-hook 'turn-on-font-lock)

To turn on Font Lock mode automatically in all modes which support it, customize the user option global-font-lock-mode or use the function global-font-lock-mode in your `.emacs' file, like this:

(global-font-lock-mode 1)

Font Lock mode uses several specifically named faces to do its job, including font-lock-string-face, font-lock-comment-face, and others. The easiest way to find them all is to use completion on the face name in set-face-foreground.

To change the colors or the fonts used by Font Lock mode to fontify different parts of text, just change these faces. There are two ways to do it:

To get the full benefit of Font Lock mode, you need to choose a default font which has bold, italic, and bold-italic variants; or else you need to have a color or gray-scale screen.

The variable font-lock-maximum-decoration specifies the preferred level of fontification, for modes that provide multiple levels. Level 1 is the least amount of fontification; some modes support levels as high as 3. The normal default is "as high as possible." You can specify an integer, which applies to all modes, or you can specify different numbers for particular major modes; for example, to use level 1 for C/C++ modes, and the default level otherwise, use this:

(setq font-lock-maximum-decoration
      '((c-mode . 1) (c++-mode . 1)))

Fontification can be too slow for large buffers, so you can suppress it. The variable font-lock-maximum-size specifies a buffer size, beyond which buffer fontification is suppressed.

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, rely on a special convention: an open-parenthesis or open-brace in the leftmost column always defines the beginning of a defun, and is thus always outside any string or comment. (See section U.2.1 Left Margin Convention.) 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.

The variable font-lock-beginning-of-syntax-function (always buffer-local) specifies how Font Lock mode can find a position guaranteed to be outside any comment or string. In modes which use the leftmost column parenthesis convention, the default value of the variable is beginning-of-defun---that tells Font Lock mode to use the convention. If you set this variable to nil, Font Lock no longer relies on the convention. This avoids incorrect results, but the price is that, in some cases, fontification for a changed text must rescan buffer text from the beginning of the buffer. This can considerably slow down redisplay while scrolling, particularly if you are close to the end of a large buffer.

Font Lock highlighting patterns already exist for many modes, but you may want to fontify additional patterns. You can use the function font-lock-add-keywords, to add your own highlighting patterns for a particular mode. For example, to highlight `FIXME:' words in C comments, use this:

 '(("\\<\\(FIXME\\):" 1 font-lock-warning-face t)))

To remove keywords from the font-lock highlighting patterns, use the function font-lock-remove-keywords.

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J.3 Highlight Changes Mode

Use M-x highlight-changes-mode to enable a minor mode that uses faces (colors, typically) to indicate which parts of the buffer were changed most recently.

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J.4 Interactive Highlighting by Matching

It is sometimes useful to highlight the strings that match a certain regular expression. For example, you might wish to see all the references to a certain variable in a program source file, or highlight certain parts in a voluminous output of some program, or make certain cliches stand out in an article.

Use the M-x hi-lock-mode command to turn on a minor mode that allows you to specify regular expressions of the text to be highlighted. Hi-lock mode works like Font Lock (see section J.2 Font Lock mode), except that it lets you specify explicitly what parts of text to highlight. You control Hi-lock mode with these commands:

C-x w h regexp RET face RET
Highlight text that matches regexp using face face (highlight-regexp). By using this command more than once, you can highlight various parts of the text in different ways.

C-x w r regexp RET
Unhighlight regexp (unhighlight-regexp). You must enter one of the regular expressions currently specified for highlighting. (You can use completion, or choose from a menu, to enter one of them conveniently.)

C-x w l regexp RET face RET
Highlight entire lines containing a match for regexp, using face face (highlight-lines-matching-regexp).

C-x w b
Insert all the current highlighting regexp/face pairs into the buffer at point, with comment delimiters to prevent them from changing your program. This key binding runs the hi-lock-write-interactive-patterns command.

These patterns will be read the next time you visit the file while Hi-lock mode is enabled, or whenever you use the M-x hi-lock-find-patterns command.

C-x w i
Re-read regexp/face pairs in the current buffer (hi-lock-write-interactive-patterns). The list of pairs is found no matter where in the buffer it may be.

This command does nothing if the major mode is a member of the list hi-lock-exclude-modes.

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J.5 Trailing Whitespace

It is easy to leave unnecessary spaces at the end of a line without realizing it. In most cases, this 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 show-trailing-whitespace to t. Then Emacs displays trailing whitespace in the face 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.)

To delete all trailing whitespace within the current buffer's restriction (see section AC.22 Narrowing), type M-x delete-trailing-whitespace RET. (This command does not remove the form-feed characters.)

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 indicate-empty-lines to a non-nil value. The default value of this variable is controlled by the variable default-indicate-empty-lines; by setting that variable, you can enable or disable this feature for all new buffers.

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J.6 Scrolling

If a buffer contains text that is too large to fit entirely within a window that is displaying the buffer, Emacs shows a contiguous portion of the text. The portion shown always contains point.

Scrolling means moving text up or down in the window so that different parts of the text are visible. Scrolling forward means that text moves up, and new text appears at the bottom. Scrolling backward moves text down and new text appears at the top.

Scrolling happens automatically if you move point past the bottom or top of the window. You can also explicitly request scrolling with the commands in this section.

Clear screen and redisplay, scrolling the selected window to center point vertically within it (recenter).
Scroll forward (a windowful or a specified number of lines) (scroll-up).
Likewise, scroll forward.
Scroll backward (scroll-down).
Likewise, scroll backward.
arg C-l
Scroll so point is on line arg (recenter).
Scroll heuristically to bring useful information onto the screen (reposition-window).

The most basic scrolling command is C-l (recenter) with no argument. It clears the entire screen and redisplays all windows. In addition, it scrolls the selected window so that point is halfway down from the top of the window.

To read the buffer a windowful at a time, use C-v (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.

M-v (scroll-down) with no argument scrolls backward in a similar way, also with overlap. The number of lines of overlap across a C-v or M-v is controlled by the variable next-screen-context-lines; by default, it is 2. The function keys NEXT and PRIOR, or PAGEDOWN and PAGEUP, are equivalent to C-v and M-v.

The commands C-v and M-v with a numeric argument scroll the text in the selected window up or down a few lines. 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. M-v with numeric argument scrolls the text downward, bringing that many new lines into view at the top of the window. C-v with a negative argument is like 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 scroll-up because it moves the text upward on the screen. The keys PAGEDOWN and PAGEUP derive their names and customary meanings from a different convention that developed elsewhere; hence the strange result that PAGEDOWN runs scroll-up.

Some users like the full-screen scroll commands to keep point at the same screen line. To enable this behavior, set the variable scroll-preserve-screen-position to a non-nil value. This mode is convenient for browsing through a file by scrolling by screenfuls; if you come back to the screen where you started, point goes back to the line where it started. However, this mode is inconvenient when you move to the next screen in order to move point to the text there.

Another way to do scrolling is with C-l with a numeric argument. C-l does not clear the screen when given an argument; it only scrolls the selected window. With a positive argument n, it repositions text to put point n lines down from the top. An argument of zero puts point on the very top line. Point does not move with respect to the text; rather, the text and point move rigidly on the screen. C-l with a negative argument puts point that many lines from the bottom of the window. For example, C-u - 1 C-l puts point on the bottom line, and C-u - 5 C-l puts it five lines from the bottom. C-u C-l scrolls to put point at the center (vertically) of the selected window.

The C-M-l command (reposition-window) scrolls the current window heuristically in a way designed to get useful information onto the screen. For example, in a Lisp file, this command tries to get the entire current defun onto the screen if possible.

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 scroll-conservatively to a small number n, then if you move point just a little off the screen--less than n lines--then Emacs scrolls the text just far enough to bring point back on screen. By default, scroll-conservatively is 0.

When the window does scroll by a longer distance, you can control how aggressively it scrolls, by setting the variables scroll-up-aggressively and scroll-down-aggressively. The value of scroll-up-aggressively should be either nil, or a fraction f between 0 and 1. A fraction specifies where on the screen to put point when scrolling upward. More precisely, when a window scrolls up because point is above the window start, the new start position is chosen to put point f part of the window height from the top. The larger f, the more aggressive the scrolling.

nil, which is the default, scrolls to put point at the center. So it is equivalent to .5.

Likewise, scroll-down-aggressively is used for scrolling down. The value, f, specifies how far point should be placed from the bottom of the window; thus, as with scroll-up-aggressively, a larger value is more aggressive.

The variable scroll-margin restricts how close point can come to the top or bottom of a window. Its value is a number of screen lines; if point comes within that many lines of the top or bottom of the window, Emacs recenters the window. By default, scroll-margin is 0.

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J.7 Horizontal Scrolling

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 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.

When a window has been scrolled horizontally, text lines are truncated rather than continued (see section D.8 Continuation Lines), with a `$' appearing in the first column when there is text truncated to the left, and in the last column when there is text truncated to the right.

You can use these commands to do explicit horizontal scrolling.

C-x <
Scroll text in current window to the left (scroll-left).
C-x >
Scroll to the right (scroll-right).

The command C-x < (scroll-left) scrolls the selected window to the left by n columns with argument n. This moves part of the beginning of each line off the left edge of the window. With no argument, it scrolls by almost the full width of the window (two columns less, to be precise).

C-x > (scroll-right) scrolls similarly to the right. The window cannot be scrolled any farther to the right once it is displayed normally (with each line starting at the window's left margin); attempting to do so has no effect. This means that you don't have to calculate the argument precisely for C-x >; any sufficiently large argument will restore the normal display.

If you scroll a window horizontally by hand, that sets a lower bound for automatic horizontal scrolling. Automatic scrolling will continue to scroll the window, but never farther to the right than the amount you previously set by scroll-left.

To disable automatic horizontal scrolling, set the variable automatic-hscrolling to nil.

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J.8 Follow Mode

Follow mode is a minor mode that makes two windows showing the same buffer scroll as one tall "virtual window." To use Follow mode, go to a frame with just one window, split it into two side-by-side windows using C-x 3, and then type M-x follow-mode. From then on, you can edit the buffer in either of the two windows, or scroll either one; the other window follows it.

In Follow mode, if you move point outside the portion visible in one window and into the portion visible in the other window, that selects the other window--again, treating the two as if they were parts of one large window.

To turn off Follow mode, type M-x follow-mode a second time.

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J.9 Selective Display

Emacs has the ability to hide lines indented more than a certain number of columns (you specify how many columns). You can use this to get an overview of a part of a program.

To hide lines, type C-x $ (set-selective-display) with a numeric argument n. Then lines with at least n columns of indentation disappear from the screen. The only indication of their presence is that three dots (`...') appear at the end of each visible line that is followed by one or more hidden ones.

The commands C-n and C-p move across the hidden lines as if they were not there.

The hidden lines are still present in the buffer, and most editing commands see them as usual, so you may find point in the middle of the hidden text. When this happens, the cursor appears at the end of the previous line, after the three dots. If point is at the end of the visible line, before the newline that ends it, the cursor appears before the three dots.

To make all lines visible again, type C-x $ with no argument.

If you set the variable selective-display-ellipses to nil, the three dots do not appear at the end of a line that precedes hidden lines. Then there is no visible indication of the hidden lines. This variable becomes local automatically when set.

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J.10 Optional Mode Line Features

The current line number of point appears in the mode line when Line Number mode is enabled. Use the command M-x line-number-mode to turn this mode on and off; normally it is on. The line number appears before the buffer percentage pos, with the letter `L' to indicate what it is. See section AD.1 Minor Modes, for more information about minor modes and about how to use this command.

If you have narrowed the buffer (see section AC.22 Narrowing), the displayed line number is relative to the accessible portion of the buffer.

If the buffer is very large (larger than the value of 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 nil to remove the limit.

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 line-number-display-limit-width. The default value is 200 characters.

You can also display the current column number by turning on Column Number mode. It displays the current column number preceded by the letter `C'. Type M-x column-number-mode to toggle this mode.

Emacs can optionally display the time and system load in all mode lines. To enable this feature, type M-x display-time or customize the option display-time-mode. The information added to the mode line usually appears after the buffer name, before the mode names and their parentheses. It looks like this:

hh:mmpm l.ll

Here hh and mm are the hour and minute, followed always by `am' or `pm'. l.ll is the average number of running processes in the whole system recently. (Some fields may be missing if your operating system cannot support them.) If you prefer time display in 24-hour format, set the variable display-time-24hr-format to t.

The word `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 `Mail' by customizing display-time-use-mail-icon; this may save some space on the mode line. You can customize display-time-mail-face to make the mail indicator prominent.

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 mode-line face in your `.emacs' init file, like this:

(set-face-attribute 'mode-line nil :box nil)

Alternatively, you can turn off the box attribute in your `.Xdefaults' file:

Emacs.mode-line.AttributeBox: off

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J.11 How Text Is Displayed

ASCII printing characters (octal codes 040 through 0176) in Emacs buffers are displayed with their graphics, as are non-ASCII multibyte printing characters (octal codes above 0400).

Some ASCII control characters are displayed in special ways. The newline character (octal code 012) is displayed by starting a new line. The tab character (octal code 011) is displayed by moving to the next tab stop column (normally every 8 columns).

Other ASCII control characters are normally displayed as a caret (`^') followed by the non-control version of the character; thus, control-A is displayed as `^A'.

Non-ASCII characters 0200 through 0237 (octal) are displayed with octal escape sequences; thus, character code 0230 (octal) is displayed as `\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 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. See section Q.13 Single-byte Character Set Support.

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J.12 Customization of Display

This section contains information for customization only. Beginning users should skip it.

The variable 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 mode-line face. See section B.3 The Mode Line. However, if mode-line-inverse-video has a value of nil, then the mode-line face will be ignored, and mode-lines will be drawn using the default text face. See section J.1 Using Multiple Typefaces.

If the variable inverse-video is non-nil, Emacs attempts to invert all the lines of the display from what they normally are.

If the variable visible-bell is non-nil, Emacs attempts to make the whole screen blink when it would normally make an audible bell sound. This variable has no effect if your terminal does not have a way to make the screen blink.

When you reenter Emacs after suspending, Emacs normally clears the screen and redraws the entire display. On some terminals with more than one page of memory, it is possible to arrange the termcap entry so that the `ti' and `te' strings (output to the terminal when Emacs is entered and exited, respectively) switch between pages of memory so as to use one page for Emacs and another page for other output. Then you might want to set the variable no-redraw-on-reenter non-nil; this tells Emacs to assume, when resumed, that the screen page it is using still contains what Emacs last wrote there.

The variable echo-keystrokes controls the echoing of multi-character keys; its value is the number of seconds of pause required to cause echoing to start, or zero meaning don't echo at all. See section B.2 The Echo Area.

If the variable ctl-arrow is nil, all control characters in the buffer are displayed with octal escape sequences, except for newline and tab. Altering the value of ctl-arrow makes it local to the current buffer; until that time, the default value is in effect. The default is initially t. See section `Display Tables' in The Emacs Lisp Reference Manual.

Normally, a tab character in the buffer is displayed as whitespace which extends to the next display tab stop position, and display tab stops come at intervals equal to eight spaces. The number of spaces per tab is controlled by the variable tab-width, which is made local by changing it, just like ctl-arrow. Note that how the tab character in the buffer is displayed has nothing to do with the definition of TAB as a command. The variable tab-width must have an integer value between 1 and 1000, inclusive.

If the variable truncate-lines is non-nil, then each line of text gets just one screen line for display; if the text line is too long, display shows only the part that fits. If truncate-lines is nil, then long text lines display as more than one screen line, enough to show the whole text of the line. See section D.8 Continuation Lines. Altering the value of truncate-lines makes it local to the current buffer; until that time, the default value is in effect. The default is initially nil.

If the variable truncate-partial-width-windows is non-nil, it forces truncation rather than continuation in any window less than the full width of the screen or frame, regardless of the value of truncate-lines. For information about side-by-side windows, see O.2 Splitting Windows. See also section `Display' in The Emacs Lisp Reference Manual.

The variable baud-rate holds the output speed of the terminal, as far as Emacs knows. Setting this variable does not change the speed of actual data transmission, but the value is used for calculations. On terminals, it affects padding, and decisions about whether to scroll part of the screen or redraw it instead. It also affects the behavior of incremental search.

On window-systems, baud-rate is only used to determine how frequently to look for pending input during display updating. A higher value of baud-rate means that check for pending input will be done less frequently.

You can customize the way any particular character code is displayed by means of a display table. See section `Display Tables' in The Emacs Lisp Reference Manual.

On a window system, Emacs can optionally display the mouse pointer in a special shape to say that Emacs is busy. To turn this feature on or off, customize the group cursor. You can also control the amount of time Emacs must remain busy before the busy indicator is displayed, by setting the variable hourglass-delay.

On some text-only terminals, bold face and inverse video together result in text that is hard to read. Call the function tty-suppress-bold-inverse-default-colors with a non-nil argument to suppress the effect of bold-face in this case.

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J.13 Displaying the Cursor

There are a number of ways to customize the display of the cursor. M-x hl-line-mode enables or disables a minor mode which highlights the line containing point. On window systems, the command 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 cursor Custom group (see section AD.2.2 Easy Customization Interface).

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 x-stretch-cursor to a non-nil value.

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 cursor-in-non-selected-windows to assign it a nil value.

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