| 1 | @c This is part of the Emacs manual. |
| 2 | @c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 2001, 2002, |
| 3 | @c 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc. |
| 4 | @c See file emacs.texi for copying conditions. |
| 5 | @node Screen, User Input, Acknowledgments, Top |
| 6 | @chapter The Organization of the Screen |
| 7 | @cindex screen |
| 8 | @cindex parts of the screen |
| 9 | |
| 10 | On a text-only terminal, the Emacs display occupies the whole |
| 11 | screen. On a graphical display, such as on GNU/Linux using the X |
| 12 | Window System, Emacs creates its own windows to use. We use the term |
| 13 | @dfn{frame} to mean the entire text-only screen or an entire |
| 14 | system-level window used by Emacs. Emacs uses both kinds of frames, |
| 15 | in the same way, to display your editing. Emacs normally starts out |
| 16 | with just one frame, but you can create additional frames if you wish. |
| 17 | @xref{Frames}. |
| 18 | |
| 19 | When you start Emacs, the main central area of the frame, all except |
| 20 | for the top and bottom and sides, displays the text you are editing. |
| 21 | This area is called @dfn{the window}. At the top there is normally a |
| 22 | @dfn{menu bar} where you can access a series of menus; then there may |
| 23 | be a @dfn{tool bar}, a row of icons that perform editing commands if |
| 24 | you click on them. Below this, the window begins, often with a |
| 25 | @dfn{scroll bar} on one side. Below the window comes the last line of |
| 26 | the frame, a special @dfn{echo area} or @dfn{minibuffer window}, where |
| 27 | prompts appear and you enter information when Emacs asks for it. See |
| 28 | following sections for more information about these special lines. |
| 29 | |
| 30 | You can subdivide the window horizontally or vertically to make |
| 31 | multiple text windows, each of which can independently display some |
| 32 | file or text (@pxref{Windows}). In this manual, the word ``window'' |
| 33 | refers to the initial large window if not subdivided, or any one of |
| 34 | the multiple windows you have subdivided it into. |
| 35 | |
| 36 | At any time, one window is the @dfn{selected window}. On graphical |
| 37 | displays, the selected window normally shows a more prominent cursor |
| 38 | (usually solid and blinking) while other windows show a weaker cursor |
| 39 | (such as a hollow box). Text terminals have just one cursor, so it |
| 40 | always appears in the selected window. |
| 41 | |
| 42 | Most Emacs commands implicitly apply to the text in the selected |
| 43 | window; the text in unselected windows is mostly visible for |
| 44 | reference. However, mouse commands generally operate on whatever |
| 45 | window you click them in, whether selected or not. If you use |
| 46 | multiple frames on a graphical display, then giving the input focus to |
| 47 | a particular frame selects a window in that frame. |
| 48 | |
| 49 | Each window's last line is a @dfn{mode line}, which describes what |
| 50 | is going on in that window. It appears in different color and/or a ``3D'' |
| 51 | box if the terminal supports them; its contents normally begin with |
| 52 | @w{@samp{--:-- @ *scratch*}} when Emacs starts. The mode line |
| 53 | displays status information such as what buffer is being displayed |
| 54 | above it in the window, what major and minor modes are in use, and |
| 55 | whether the buffer contains unsaved changes. |
| 56 | |
| 57 | @menu |
| 58 | * Point:: The place in the text where editing commands operate. |
| 59 | * Echo Area:: Short messages appear at the bottom of the screen. |
| 60 | * Mode Line:: Interpreting the mode line. |
| 61 | * Menu Bar:: How to use the menu bar. |
| 62 | @end menu |
| 63 | |
| 64 | @node Point |
| 65 | @section Point |
| 66 | @cindex point |
| 67 | @cindex cursor |
| 68 | |
| 69 | Within Emacs, the active cursor shows the location at which |
| 70 | editing commands will take effect. This location is called @dfn{point}. |
| 71 | Many Emacs commands move point through the text, so that you can edit at |
| 72 | different places in it. You can also place point by clicking mouse |
| 73 | button 1 (normally the left button). |
| 74 | |
| 75 | While the cursor appears to be @emph{on} a character, you should |
| 76 | think of point as @emph{between} two characters; it points @emph{before} |
| 77 | the character that appears under the cursor. For example, if your text |
| 78 | looks like @samp{frob} with the cursor over the @samp{b}, then point is |
| 79 | between the @samp{o} and the @samp{b}. If you insert the character |
| 80 | @samp{!} at that position, the result is @samp{fro!b}, with point |
| 81 | between the @samp{!} and the @samp{b}. Thus, the cursor remains over |
| 82 | the @samp{b}, as before. |
| 83 | |
| 84 | Sometimes people speak of ``the cursor'' when they mean ``point,'' or |
| 85 | speak of commands that move point as ``cursor motion'' commands. |
| 86 | |
| 87 | If you are editing several files in Emacs, each in its own buffer, |
| 88 | each buffer has its own point location. A buffer that is not |
| 89 | currently displayed remembers its point location in case you display |
| 90 | it again later. When Emacs displays multiple windows, each window has |
| 91 | its own point location. If the same buffer appears in more than one |
| 92 | window, each window has its own point position in that buffer, and (when |
| 93 | possible) its own cursor. |
| 94 | |
| 95 | A text-only terminal has just one cursor, in the selected window. |
| 96 | The other windows do not show a cursor, even though they do have their |
| 97 | own position of point. When Emacs updates the screen on a text-only |
| 98 | terminal, it has to put the cursor temporarily at the place the output |
| 99 | goes. This doesn't mean point is there, though. Once display |
| 100 | updating finishes, Emacs puts the cursor where point is. |
| 101 | |
| 102 | On graphical displays, Emacs shows a cursor in each window; the |
| 103 | selected window's cursor is solid and blinking, and the other cursors |
| 104 | are just hollow. Thus, the most prominent cursor always shows you the |
| 105 | selected window, on all kinds of terminals. |
| 106 | |
| 107 | @xref{Cursor Display}, for customizable variables that control display |
| 108 | of the cursor or cursors. |
| 109 | |
| 110 | The term ``point'' comes from the character @samp{.}, which was the |
| 111 | command in TECO (the language in which the original Emacs was written) |
| 112 | for accessing the value now called ``point.'' |
| 113 | |
| 114 | @node Echo Area |
| 115 | @section The Echo Area |
| 116 | @cindex echo area |
| 117 | |
| 118 | The line at the bottom of the frame (below the mode line) is the |
| 119 | @dfn{echo area}. It is used to display small amounts of text for |
| 120 | various purposes. |
| 121 | |
| 122 | @dfn{Echoing} means displaying the characters that you type. At the |
| 123 | command line, the operating system normally echoes all your input. |
| 124 | Emacs handles echoing differently. |
| 125 | |
| 126 | Single-character commands do not echo in Emacs, and multi-character |
| 127 | commands echo only if you pause while typing them. As soon as you pause |
| 128 | for more than a second in the middle of a command, Emacs echoes all the |
| 129 | characters of the command so far. This is to @dfn{prompt} you for the |
| 130 | rest of the command. Once echoing has started, the rest of the command |
| 131 | echoes immediately as you type it. This behavior is designed to give |
| 132 | confident users fast response, while giving hesitant users maximum |
| 133 | feedback. You can change this behavior by setting a variable |
| 134 | (@pxref{Display Custom}). |
| 135 | |
| 136 | @cindex error message in the echo area |
| 137 | If a command cannot do its job, it may display an @dfn{error |
| 138 | message} in the echo area. Error messages are accompanied by beeping |
| 139 | or by flashing the screen. The error also discards any input you have |
| 140 | typed ahead. |
| 141 | |
| 142 | Some commands display informative messages in the echo area. These |
| 143 | messages look much like error messages, but they are not announced |
| 144 | with a beep and do not throw away input. Sometimes the message tells |
| 145 | you what the command has done, when this is not obvious from looking |
| 146 | at the text being edited. Sometimes the sole purpose of a command is |
| 147 | to show you a message giving you specific information---for example, |
| 148 | @kbd{C-x =} (hold down @key{CTRL} and type @kbd{x}, then let go of |
| 149 | @key{CTRL} and type @kbd{=}) displays a message describing the |
| 150 | character position of point in the text and its current column in the |
| 151 | window. Commands that take a long time often display messages ending |
| 152 | in @samp{...} while they are working, and add @samp{done} at the end |
| 153 | when they are finished. They may also indicate progress with |
| 154 | percentages. |
| 155 | |
| 156 | @cindex @samp{*Messages*} buffer |
| 157 | @cindex saved echo area messages |
| 158 | @cindex messages saved from echo area |
| 159 | Echo-area informative messages are saved in an editor buffer named |
| 160 | @samp{*Messages*}. (We have not explained buffers yet; see |
| 161 | @ref{Buffers}, for more information about them.) If you miss a message |
| 162 | that appears briefly on the screen, you can switch to the |
| 163 | @samp{*Messages*} buffer to see it again. (Successive progress messages |
| 164 | are often collapsed into one in that buffer.) |
| 165 | |
| 166 | @vindex message-log-max |
| 167 | The size of @samp{*Messages*} is limited to a certain number of |
| 168 | lines. The variable @code{message-log-max} specifies how many lines. |
| 169 | Once the buffer has that many lines, adding lines at the end deletes lines |
| 170 | from the beginning, to keep the size constant. @xref{Variables}, for |
| 171 | how to set variables such as @code{message-log-max}. |
| 172 | |
| 173 | The echo area is also used to display the @dfn{minibuffer}, a window |
| 174 | where you can input arguments to commands, such as the name of a file |
| 175 | to be edited. When the minibuffer is in use, the echo area begins |
| 176 | with a prompt string that usually ends with a colon; also, the cursor |
| 177 | appears in that line because it is the selected window. You can |
| 178 | always get out of the minibuffer by typing @kbd{C-g}. |
| 179 | @xref{Minibuffer}. |
| 180 | |
| 181 | @node Mode Line |
| 182 | @section The Mode Line |
| 183 | @cindex mode line |
| 184 | @cindex top level |
| 185 | @c |
| 186 | |
| 187 | Each text window's last line is a @dfn{mode line}, which describes |
| 188 | what is going on in that window. The mode line starts and ends with |
| 189 | dashes. When there is only one text window, the mode line appears |
| 190 | right above the echo area; it is the next-to-last line in the frame. |
| 191 | On a text-only terminal, the mode line is in inverse video if the |
| 192 | terminal supports that; on a graphics display, the mode line has a 3D |
| 193 | box appearance to help it stand out. The mode line of the selected |
| 194 | window is highlighted if possible; see @ref{Optional Mode Line}, for |
| 195 | more information. |
| 196 | |
| 197 | Normally, the mode line looks like this: |
| 198 | |
| 199 | @example |
| 200 | -@var{cs}:@var{ch}@var{R}-@var{fr} @var{buf} @var{pos} @var{line} (@var{major} @var{minor})------ |
| 201 | @end example |
| 202 | |
| 203 | @noindent |
| 204 | This gives information about the window and the buffer it displays: the |
| 205 | buffer's name, what major and minor modes are in use, whether the |
| 206 | buffer's text has been changed, and how far down the buffer you are |
| 207 | currently looking. |
| 208 | |
| 209 | @var{ch} contains two stars @samp{**} if the text in the buffer has |
| 210 | been edited (the buffer is ``modified''), or @samp{--} if the buffer has |
| 211 | not been edited. For a read-only buffer, it is @samp{%*} if the buffer |
| 212 | is modified, and @samp{%%} otherwise. |
| 213 | |
| 214 | @var{R} is @samp{@@} if the default-directory for the current buffer |
| 215 | is on a remote machine, or a hyphen otherwise. |
| 216 | |
| 217 | @var{fr} gives the selected frame name (@pxref{Frames}). It appears |
| 218 | only on text-only terminals. The initial frame's name is @samp{F1}. |
| 219 | |
| 220 | @var{buf} is the name of the window's @dfn{buffer}. Usually this is |
| 221 | the same as the name of a file you are editing. @xref{Buffers}. |
| 222 | |
| 223 | The buffer displayed in the selected window (the window with the |
| 224 | cursor) is the @dfn{current buffer}, where editing happens. When a |
| 225 | command's effect applies to ``the buffer,'' we mean it does those |
| 226 | things to the current buffer. |
| 227 | |
| 228 | @var{pos} tells you whether there is additional text above the top of |
| 229 | the window, or below the bottom. If your buffer is small and it is all |
| 230 | visible in the window, @var{pos} is @samp{All}. Otherwise, it is |
| 231 | @samp{Top} if you are looking at the beginning of the buffer, @samp{Bot} |
| 232 | if you are looking at the end of the buffer, or @samp{@var{nn}%}, where |
| 233 | @var{nn} is the percentage of the buffer above the top of the window. |
| 234 | With Size Indication mode, you can display the size of the buffer as |
| 235 | well. @xref{Optional Mode Line}. |
| 236 | |
| 237 | @var{line} is @samp{L} followed by the current line number of point. |
| 238 | This is present when Line Number mode is enabled (it normally is). |
| 239 | You can display the current column number too, by turning on Column |
| 240 | Number mode. It is not enabled by default because it is somewhat |
| 241 | slower. @xref{Optional Mode Line}. |
| 242 | |
| 243 | @var{major} is the name of the @dfn{major mode} in effect in the |
| 244 | buffer. A buffer can only be in one major mode at a time. The major |
| 245 | modes available include Fundamental mode (the least specialized), Text |
| 246 | mode, Lisp mode, C mode, Texinfo mode, and many others. @xref{Major |
| 247 | Modes}, for details of how the modes differ and how to select |
| 248 | them. |
| 249 | |
| 250 | Some major modes display additional information after the major mode |
| 251 | name. For example, Rmail buffers display the current message number and |
| 252 | the total number of messages. Compilation buffers and Shell buffers |
| 253 | display the status of the subprocess. |
| 254 | |
| 255 | @var{minor} is a list of some of the @dfn{minor modes} that are |
| 256 | turned on at the moment in the window's chosen buffer. For example, |
| 257 | @samp{Fill} means that Auto Fill mode is on. @samp{Abbrev} means that |
| 258 | Word Abbrev mode is on. @samp{Ovwrt} means that Overwrite mode is on. |
| 259 | @xref{Minor Modes}, for more information. |
| 260 | |
| 261 | @samp{Narrow} means that the buffer being displayed has editing |
| 262 | restricted to only a portion of its text. (This is not really a minor |
| 263 | mode, but is like one.) @xref{Narrowing}. @samp{Def} means that a |
| 264 | keyboard macro is being defined. @xref{Keyboard Macros}. |
| 265 | |
| 266 | In addition, if Emacs is inside a recursive editing level, square |
| 267 | brackets (@samp{[@dots{}]}) appear around the parentheses that |
| 268 | surround the modes. If Emacs is in one recursive editing level within |
| 269 | another, double square brackets appear, and so on. Since recursive |
| 270 | editing levels affect Emacs globally, not just one buffer, the square |
| 271 | brackets appear in every window's mode line or not in any of them. |
| 272 | @xref{Recursive Edit}.@refill |
| 273 | |
| 274 | @var{cs} states the coding system used for the file you are editing. |
| 275 | A dash indicates the default state of affairs: no code conversion, |
| 276 | except for end-of-line translation if the file contents call for that. |
| 277 | @samp{=} means no conversion whatsoever. Nontrivial code conversions |
| 278 | are represented by various letters---for example, @samp{1} refers to ISO |
| 279 | Latin-1. @xref{Coding Systems}, for more information. |
| 280 | |
| 281 | On a text-only terminal, @var{cs} includes two additional characters |
| 282 | which describe the coding system for keyboard input and the coding |
| 283 | system for terminal output. They come right before the coding system |
| 284 | used for the file you are editing. |
| 285 | |
| 286 | If you are using an input method, a string of the form |
| 287 | @samp{@var{i}>} is added to the beginning of @var{cs}; @var{i} |
| 288 | identifies the input method. (Some input methods show @samp{+} or |
| 289 | @samp{@@} instead of @samp{>}.) @xref{Input Methods}. |
| 290 | |
| 291 | When multibyte characters are not enabled, @var{cs} does not appear at |
| 292 | all. @xref{Enabling Multibyte}. |
| 293 | |
| 294 | @cindex end-of-line conversion, mode-line indication |
| 295 | The colon after @var{cs} changes to another string in some cases. |
| 296 | Emacs uses newline characters to separate lines in the buffer. Some |
| 297 | files use different conventions for separating lines: either |
| 298 | carriage-return linefeed (the MS-DOS convention) or just |
| 299 | carriage-return (the Macintosh convention). If the buffer's file uses |
| 300 | carriage-return linefeed, the colon changes to either a backslash |
| 301 | (@samp{\}) or @samp{(DOS)}, depending on the operating system. If the |
| 302 | file uses just carriage-return, the colon indicator changes to either |
| 303 | a forward slash (@samp{/}) or @samp{(Mac)}. On some systems, Emacs |
| 304 | displays @samp{(Unix)} instead of the colon for files that use newline |
| 305 | as the line separator. |
| 306 | |
| 307 | @xref{Optional Mode Line}, to add other handy information to the |
| 308 | mode line, such as the size of the buffer, the current column number |
| 309 | of point, and whether new mail for you has arrived. |
| 310 | |
| 311 | The mode line is mouse-sensitive; when you move the mouse across |
| 312 | various parts of it, Emacs displays help text to say what a click in |
| 313 | that place will do. @xref{Mode Line Mouse}. |
| 314 | |
| 315 | @node Menu Bar |
| 316 | @section The Menu Bar |
| 317 | @cindex menu bar |
| 318 | |
| 319 | Each Emacs frame normally has a @dfn{menu bar} at the top which you |
| 320 | can use to perform common operations. There's no need to list them |
| 321 | here, as you can more easily see them yourself. |
| 322 | |
| 323 | @kindex M-` |
| 324 | @kindex F10 |
| 325 | @findex tmm-menubar |
| 326 | @findex menu-bar-open |
| 327 | On a graphical display, you can use the mouse to choose a command |
| 328 | from the menu bar. A right-arrow at the end of the menu item means it |
| 329 | leads to a subsidiary menu; @samp{...} at the end means that the |
| 330 | command invoked will read arguments (further input from you) before it |
| 331 | actually does anything. |
| 332 | |
| 333 | You can also invoke the first menu bar item by pressing @key{F10} (to run |
| 334 | the command @code{menu-bar-open}). You can then navigate the menus with |
| 335 | the arrow keys. You select an item by pressing @key{RET} and cancel menu |
| 336 | navigation with @key{ESC}. |
| 337 | |
| 338 | To view the full command name and documentation for a menu item, type |
| 339 | @kbd{C-h k}, and then select the menu bar with the mouse in the usual |
| 340 | way (@pxref{Key Help}). |
| 341 | |
| 342 | On text-only terminals with no mouse, you can use the menu bar by |
| 343 | typing @kbd{M-`} or @key{F10} (these run the command |
| 344 | @code{tmm-menubar}). This lets you select a menu item with the |
| 345 | keyboard. A provisional choice appears in the echo area. You can use |
| 346 | the up and down arrow keys to move through the menu to different |
| 347 | items, and then you can type @key{RET} to select the item. |
| 348 | |
| 349 | Each menu item also has an assigned letter or digit which designates |
| 350 | that item; it is usually the initial of some word in the item's name. |
| 351 | This letter or digit is separated from the item name by @samp{=>}. You |
| 352 | can type the item's letter or digit to select the item. |
| 353 | |
| 354 | Some of the commands in the menu bar have ordinary key bindings as |
| 355 | well; one such binding is shown in parentheses after the item itself. |
| 356 | |
| 357 | @ignore |
| 358 | arch-tag: 104ba40e-d972-4866-a542-a98be94bdf2f |
| 359 | @end ignore |