X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/86354bc09a1a29a6bd7a70e1fbd364f4b1afff5f..a7b94a53d245bcd41af801a4b8e6e2dd6b46a735:/man/display.texi diff --git a/man/display.texi b/man/display.texi index ea55a8c488..b8ea515acf 100644 --- a/man/display.texi +++ b/man/display.texi @@ -1,5 +1,5 @@ @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 @@ -15,9 +15,10 @@ display it. * 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. @@ -30,11 +31,18 @@ display it. @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 @@ -62,7 +70,7 @@ background color. @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 @@ -93,12 +101,20 @@ faces: @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. @@ -147,7 +163,8 @@ font of LessTif/Motif menus is currently not supported; attempts to set 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 @@ -178,13 +195,14 @@ on your screen using the command @code{ps-print-buffer-with-faces}. @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 @@ -256,6 +274,9 @@ beyond which buffer fontification is suppressed. @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, @@ -292,6 +313,23 @@ comments, use this: '(("\\<\\(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}. @xref{Search-based +Fontification,,,elisp}, for documentation of the format of this list. + +@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 @@ -367,38 +405,6 @@ This command does nothing if the major mode is a member of the list @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 @@ -524,7 +530,7 @@ back on screen. By default, @code{scroll-conservatively} is 0. @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}. @@ -598,9 +604,98 @@ 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 @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 @@ -720,14 +815,19 @@ to @code{t}. @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 @@ -748,6 +848,20 @@ Alternatively, you can turn off the box attribute in your 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) @@ -785,10 +899,10 @@ users should skip it. 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 @@ -878,34 +992,48 @@ or off, customize the group @code{cursor}. You can also control the 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.