[chise/xemacs-chise.git.1] / man / xemacs / frame.texi

@node Frame, Keystrokes, Concept Index, Top
@comment  node-name,  next,  previous,  up
@chapter The XEmacs Frame
@cindex frame
@cindex window
@cindex buffer

@table @asis
@item Frame
In many environments, such as a tty terminal, an XEmacs frame
literally takes up the whole screen.  If you are
running XEmacs in a multi-window system like the X Window System, the
XEmacs frame takes up one X window.  @xref{XEmacs under X}, for more
information.@refill

@item Window
No matter what environment you are running in, XEmacs allows you to look
at several buffers at the same time by having several windows be part of
the frame.  Often, the whole frame is taken up by just one window, but
you can split the frame into two or more subwindows.  If you are
running XEmacs under the X window system, that means you can have several
@dfn{XEmacs windows} inside the X window that contains the XEmacs frame.
You can even have multiple frames in different X windows, each with
their own set of subwindows. 
@refill
@end table

Each XEmacs frame displays a variety of information: 
@itemize @bullet
@item
The biggest area usually displays the text you are editing.  It may
consist of one window or of two or more windows if you need to look at two
buffers a the same time. 
@item
Below each text window's last line is a @dfn{mode line} (@pxref{Mode
Line}), which describes what is going on in that window.  The mode line
is in inverse video if the terminal supports that.  If there are several
XEmacs windows in one frame, each window has its own mode line.
@item
At the bottom of each XEmacs frame is the @dfn{echo area} or @dfn{minibuffer
window}(@pxref{Echo Area}).  It is used by XEmacs to exchange information
with the user.  There is only one echo area per XEmacs frame.
@item
If you are running XEmacs under the X Window System, a
menu bar at the top of the frame makes shortcuts to several of the
commands available (@pxref{Pull-down Menus}).
@end itemize

  You can subdivide the XEmacs frame into multiple text windows, and use
each window for a different file (@pxref{Windows}).  Multiple XEmacs
windows are tiled vertically on the XEmacs frame.  The upper XEmacs window
is separated from the lower window by its mode line.

  When there are multiple, tiled XEmacs windows on a single XEmacs frame,
the XEmacs window receiving input from the keyboard has the @dfn{keyboard
focus} and is called the @dfn{selected window}.  The selected window
contains the cursor, which indicates the insertion point.  If you are
working in an environment that permits multiple XEmacs frames, and you
move the focus from one XEmacs frame into another, the
selected window is the one that was last selected in that frame.

  The same text can be displayed simultaneously in several XEmacs
windows, which can be in different XEmacs frames.  If you alter the text
in an XEmacs buffer by editing it in one XEmacs window, the changes are
visible in all XEmacs windows containing that buffer.


@menu
* Point::               The place in the text where editing commands operate.  
* Echo Area::           Short messages appear at the bottom of the frame.  
* Mode Line::           Interpreting the mode line.  
* XEmacs under X::      Some information on using XEmacs under the X 
                        Window System. 
@end menu

@node Point, Echo Area, Frame, Frame
@comment  node-name,  next,  previous,  up
@section Point
@cindex point
@cindex cursor

  When XEmacs is running, the cursor shows the location at which editing
commands will take effect.  This location is called @dfn{point}.  You
can use keystrokes or the mouse cursor to move point through the text
and edit the text at different places.

  While the cursor appears to point @var{at} a character, you should
think of point as @var{between} two characters: it points @var{before}
the character on which the cursor appears.  The exception is at the
end of the line, where the cursor appears after the last character of
the line.  Where the display is capable, the cursor at the end of the
line will appear differently from a cursor over whitespace at the end
of the line.  (In an X Windows frame, the end-of-line cursor is half
the width of a within-line cursor.)  Sometimes people speak of ``the
cursor'' when they mean ``point,'' or speak of commands that move
point as ``cursor motion'' commands.

 Each XEmacs frame has only one cursor.  When output is in progress, the cursor
must appear where the typing is being done.  This does not mean that
point is moving.  It is only that XEmacs has no way to show you the
location of point except when the terminal is idle.

  If you are editing several files in XEmacs, each file has its own point
location.  A file that is not being displayed remembers where point is.
Point becomes visible at the correct location when you look at the file again.

  When there are multiple text windows, each window has its own point
location.  The cursor shows the location of point in the selected
window.  The visible cursor also shows you which window is selected.  If
the same buffer appears in more than one window, point can be moved in
each window independently.

  The term `point' comes from the character @samp{.}, which was the
command in TECO (the language in which the original Emacs was written)
for accessing the value now called `point'.

@node Echo Area, Mode Line, Point, Frame
@section The Echo Area
@cindex echo area

  The line at the bottom of the frame (below the mode line) is the
@dfn{echo area}.  XEmacs uses this area to communicate with the user:

@itemize @bullet
@item
  @dfn{Echoing} means printing out the characters that the user types.  XEmacs
never echoes single-character commands.  Multi-character commands are
echoed only if you pause while typing them: As soon as you pause for more
than one second in the middle of a command, all the characters of the command
so far are echoed.  This is intended to @dfn{prompt} you for the rest of
the command.  Once echoing has started, the rest of the command is echoed
immediately as you type it.  This behavior is designed to give confident
users fast response, while giving hesitant users maximum feedback.  You
can change this behavior by setting a variable (@pxref{Display Vars}).
@item
  If you issue a command that cannot be executed, XEmacs may print an
@dfn{error message} in the echo area.  Error messages are accompanied by
a beep or by flashing the frame.  Any input you have typed ahead is
thrown away when an error happens.
@item
  Some commands print informative messages in the echo area.  These
messages look similar to error messages, but are not announced with a
beep and do not throw away input.  Sometimes a message tells you what the
command has done, when this is not obvious from looking at the text being
edited.  Sometimes the sole purpose of a command is to print a message
giving you specific information.  For example, the command @kbd{C-x =} is
used to print a message describing the character position of point in the
text and its current column in the window.  Commands that take a long time
often display messages ending in @samp{...} while they are working, and
add @samp{done} at the end when they are finished.
@item
  The echo area is also used to display the @dfn{minibuffer}, a window
that is used for reading arguments to commands, such as the name of a
file to be edited.  When the minibuffer is in use, the echo area displays
with a prompt string that usually ends with a colon.  The cursor
appears after the prompt.  You can always get out of the minibuffer by
typing @kbd{C-g}.  @xref{Minibuffer}.
@end itemize

@node Mode Line, XEmacs under X, Echo Area, Frame
@comment  node-name,  next,  previous,  up
@section The Mode Line
@cindex mode line
@cindex top level

  Each text window's last line is a @dfn{mode line} which describes what is
going on in that window.  When there is only one text window, the mode line
appears right above the echo area.  The mode line is in inverse video if
the terminal supports that, starts and ends with dashes, and contains text
like @samp{XEmacs:@: @var{something}}.

  If a mode line has something else in place of @samp{XEmacs:@:
@var{something}}, the window above it is in a special subsystem
such as Dired.  The mode line then indicates the status of the
subsystem.

  Normally, the mode line has the following appearance:

@example
--@var{ch}-XEmacs: @var{buf}      (@var{major} @var{minor})----@var{pos}------
@end example

@noindent
This gives information about the buffer being displayed in the window: the
buffer's name, what major and minor modes are in use, whether the buffer's
text has been changed, and how far down the buffer you are currently
looking.

  @var{ch} contains two stars (@samp{**}) if the text in the buffer has been
edited (the buffer is ``modified''), or two dashes (@samp{--}) if the
buffer has not been edited.  Exception: for a read-only buffer, it is 
@samp{%%}.

  @var{buf} is the name of the window's chosen @dfn{buffer}.  The chosen
buffer in the selected window (the window that the cursor is in) is also
XEmacs's selected buffer, the buffer in which editing takes place.  When
we speak of what some command does to ``the buffer'', we mean the
currently selected buffer.  @xref{Buffers}.

  @var{pos} tells you whether there is additional text above the top of
the screen or below the bottom.  If your file is small and it is
completely visible on the screen, @var{pos} is @samp{All}.  Otherwise, 
@var{pos} is @samp{Top} if you are looking at the beginning of the file,
@samp{Bot} if you are looking at the end of the file, or
@samp{@var{nn}%}, where @var{nn} is the percentage of the file above the
top of the screen.@refill

  @var{major} is the name of the @dfn{major mode} in effect in the buffer.  At
any time, each buffer is in one and only one major mode.
The available major modes include Fundamental mode (the least specialized),
Text mode, Lisp mode, and C mode.  @xref{Major Modes}, for details
on how the modes differ and how you select one.@refill

  @var{minor} is a list of some of the @dfn{minor modes} that are turned on
in the window's chosen buffer.  For example, @samp{Fill} means that Auto
Fill mode is on.  @code{Abbrev} means that Word Abbrev mode is on.
@code{Ovwrt} means that Overwrite mode is on.  @xref{Minor Modes}, for more
information.  @samp{Narrow} means that the buffer being displayed has
editing restricted to only a portion of its text.  This is not really a
minor mode, but is like one.  @xref{Narrowing}.  @code{Def} means that a
keyboard macro is being defined.  @xref{Keyboard Macros}.

  Some buffers display additional information after the minor modes.  For
example, Rmail buffers display the current message number and the total
number of messages.  Compilation buffers and Shell mode display the status
of the subprocess.

  If XEmacs is currently inside a recursive editing level, square
brackets (@samp{[@dots{}]}) appear around the parentheses that surround
the modes.  If XEmacs is in one recursive editing level within another,
double square brackets appear, and so on.  Since information on
recursive editing applies to XEmacs in general and not to any one buffer,
the square brackets appear in every mode line on the screen or not in
any of them.  @xref{Recursive Edit}.@refill

@findex display-time
  XEmacs can optionally display the time and system load in all mode lines.
To enable this feature, type @kbd{M-x display-time}.  The information added
to the mode line usually appears after the file name, before the mode names
and their parentheses.  It looks like this:

@example
@var{hh}:@var{mm}pm @var{l.ll} [@var{d}]
@end example

@noindent
(Some fields may be missing if your operating system cannot support them.)
@var{hh} and @var{mm} are the hour and minute, followed always by @samp{am}
or @samp{pm}.  @var{l.ll} is the average number of running processes in the
whole system recently.  @var{d} is an approximate index of the ratio of
disk activity to CPU activity for all users.

The word @samp{Mail} appears after the load level if there is mail for
you that you have not read yet.

@vindex mode-line-inverse-video
  Customization note: the variable @code{mode-line-inverse-video}
controls whether the mode line is displayed in inverse video (assuming
the terminal supports it); @code{nil} means no inverse video.  The
default is @code{t}.  For X frames, simply set the foreground and
background colors appropriately.
  
@node XEmacs under X, , Mode Line, Frame
@section Using XEmacs Under the X Window System
@comment  node-name,  next,  previous,  up

XEmacs can be used with the X Window System and a window manager like
MWM or TWM.  In that case, the X window manager opens, closes, and
resizes XEmacs frames.  You use the window manager's mouse gestures to
perform the operations.  Consult your window manager guide or reference
manual for information on manipulating X windows.

When you are working under X, each X window (that is, each XEmacs frame)
has a menu bar for mouse-controlled operations (@pxref{Pull-down Menus}).

@cindex multi-frame XEmacs
@findex make-frame
XEmacs under X is also a multi-frame XEmacs.  You can use the @b{New
Frame} menu item from the @b{File} menu to create a new XEmacs frame in a
new X window from the same process.  The different frames will share the
same buffer list, but you can look at different buffers in the different
frames.

@findex find-file-other-frame
The function @code{find-file-other-frame} is just like @code{find-file},
but creates a new frame to display the buffer in first.  This is
normally bound to @kbd{C-x 5 C-f}, and is what the @b{Open File, New
Frame} menu item does.

@findex switch-to-buffer-other-frame
The function @code{switch-to-buffer-other-frame} is just like
@code{switch-to-buffer}, but creates a new frame to display the buffer
in first.  This is normally bound to @kbd{C-x 5 b}.

@vindex default-frame-alist
You can specify a different default frame size other than the one provided.
Use the variable @code{default-frame-alist}, which is an alist of default
values for frame creation other than the first one.  These may be set in
your init file, like this:  

@example
  (setq default-frame-alist '((width . 80) (height . 55)))
@end example

@vindex x-frame-defaults
For values specific to the first XEmacs frame, you must use X resources.
The variable @code{x-frame-defaults} takes an alist of default frame
creation parameters for X window frames.  These override what is
specified in @file{~/.Xdefaults} but are overridden by the arguments to
the particular call to @code{x-create-frame}.

@vindex create-frame-hook
When you create a new frame, the variable @code{create-frame-hook}
is called with one argument, the frame just created.

If you want to close one or more of the X windows you created using
@b{New Frame}, use the @b{Delete Frame} menu item from the @b{File} menu.  

@vindex frame-title-format
@vindex frame-icon-title-format
If you are working with multiple frames, some special information
applies:
@itemize @bullet
@item
Two variables, @code{frame-title-format} and
@code{frame-icon-title-format} determine the title of the frame and
the title of the icon that results if you shrink the frame.

@vindex auto-lower-frame
@vindex auto-raise-frame
@item
The variables @code{auto-lower-frame} and @code{auto-raise-frame}
position a frame. If true, @code{auto-lower-frame} lowers a frame to
the bottom when it is no longer selected. If true,
@code{auto-raise-frame} raises a frame to the top when it is
selected. Under X, most ICCCM-compliant window managers will have
options to do this for you, but these variables are provided in case you
are using a broken window manager.

@item
There is a new frame/modeline format directive, %S, which expands to
the name of the current frame (a frame's name is distinct from its
title; the name is used for resource lookup, among other things, and the
title is simply what appears above the window.)
@end itemize