SXEmacs v22.1.16 is released!

[sxemacs] / info / sxemacs / frame.texi

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

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

@item Window
No matter what environment you are running in, SXEmacs 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 SXEmacs under the X window system, that means you can have several
@dfn{SXEmacs windows} inside the X window that contains the SXEmacs frame.
You can even have multiple frames in different X windows, each with
their own set of subwindows.
@refill
@end table

Each SXEmacs 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
SXEmacs windows in one frame, each window has its own mode line.
@item
At the bottom of each SXEmacs frame is the @dfn{echo area} or @dfn{minibuffer
window}(@pxref{Echo Area}).  It is used by SXEmacs to exchange information
with the user.  There is only one echo area per SXEmacs frame.
@item
If you are running SXEmacs under a graphical windowing system, a
menu bar at the top of the frame makes shortcuts to several of the
commands available (@pxref{Pull-down Menus}).
@item
Under a graphical windowing system, a
toolbar at the top of the frame, just under the menu bar if it exists,
provides ``one-touch'' shortcuts to several commands.  (Not yet
documented.)
@item
Under a graphical windowing system, a
gutter at the top (under the toolbar) and/or bottom of the frame
provides advanced GUI facilities like tab controls for rapid switching
among related windows and progress bars for time-consuming operations
like downloads across the Internet.  Gutters are an experimental feature
introduced in SXEmacs version 21.2.  (Not yet documented.)
@end itemize

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

  When there are multiple, tiled SXEmacs windows on a single SXEmacs frame,
the SXEmacs 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 SXEmacs frames, and you
move the focus from one SXEmacs 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 SXEmacs
windows, which can be in different SXEmacs frames.  If you alter the text
in an SXEmacs buffer by editing it in one SXEmacs window, the changes are
visible in all SXEmacs 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.
* GUI Components::      Menubar, toolbars, gutters.
* SXEmacs under X::      Some information on using SXEmacs 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 SXEmacs 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 SXEmacs 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 SXEmacs has no way to show you the
location of point except when the terminal is idle.

  If you are editing several files in SXEmacs, 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}.  SXEmacs uses this area to communicate with the user:

@itemize @bullet
@item
  @dfn{Echoing} means printing out the characters that the user types.  SXEmacs
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, SXEmacs 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, GUI Components, 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{SXEmacs:@: @var{something}}.

  If a mode line has something else in place of @samp{SXEmacs:@:
@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}-SXEmacs: @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
SXEmacs'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 SXEmacs is currently inside a recursive editing level, square
brackets (@samp{[@dots{}]}) appear around the parentheses that surround
the modes.  If SXEmacs is in one recursive editing level within another,
double square brackets appear, and so on.  Since information on
recursive editing applies to SXEmacs 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
  SXEmacs 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 GUI Components, SXEmacs under X, Mode Line, Frame
@comment  node-name,  next,  previous,  up
@section GUI Components

When executed in a graphical windowing environment such as the X Window
System or Microsoft Windows, SXEmacs displays several graphical user
interface components such as scrollbars, menubars, toolbars, and
gutters.  By default there is a vertical scrollbar at the right of each
frame, and at the top of the frame there is a menubar, a toolbar, and a
gutter, in that order.  Gutters can contain any of several widgets, but
the default configuration puts a set of "notebook tabs" which you can
use as a shortcut for selecting any of several related buffers in a
given frame.  Operating the GUI components is "obvious":  click on the
menubar to pull down a menu, on a button in the toolbar to invoke a
function, and on a tab in the gutter to switch buffers.

@menu
* Menubar Basics::      How SXEmacs uses the menubar.
* Scrollbar Basics::    How SXEmacs uses scrollbars.
* Mode Line Basics::    How SXEmacs uses modelines.
* Toolbar Basics::      How SXEmacs uses toolbars.
* Gutter Basics::       How SXEmacs uses gutters.
* Inhibiting::          What if you don't like GUI?
* Customizing::         Position, orientation, and appearance of GUI objects.
@end menu

@node Menubar Basics, Scrollbar Basics, , GUI Components
@comment  node-name,  next,  previous,  up
@section The SXEmacs Menubar

The SXEmacs menubar is intended to be conformant to the usual conventions
for menubars, although conformance is not yet perfect.  The menu at the
extreme right is the @samp{Help} menu, which should always be
available.  It provides access to all the SXEmacs help facilities
available through @kbd{C-h}, as well as samples of various configuration
files like @samp{~/.Xdefaults} and @samp{~/.emacs}.  At the extreme left
is the @samp{Files} menu, which provides the usual file reading,
writing, and printing operations, as well as operations like revert
buffer from most recent save.  The next menu from the left is the
@samp{Edit} menu, which provides the @samp{Undo} operation as well as
cutting and pasting, searching, and keyboard macro definition and
execution.

@c #### w3.el and VM should get cross-references here.
SXEmacs provides a very dynamic environment, and the Lisp language makes
for highly flexible applications.  The menubar reflects this: many menus
(eg, the @samp{Buffers} menu, @pxref{Buffers Menu}) contain items
determined by the current state of SXEmacs, and most major modes and many
minor modes add items to menus and even whole menus to the menubar.  In
fact, some applications like w3.el and VM provide so many menus that
they define a whole new menubar and add a button that allows convenient
switching between the ``SXEmacs menubar'' and the ``application
menubar''.  Such applications normally bind themselves to a particular
frame, and this switching only takes place on frames where such an
application is active (ie, the current window of the frame is displaying
a buffer in the appropriate major mode).

Other menus which are typically available are the @samp{Options},
@samp{Tools}, @samp{Buffers}, @samp{Apps}, and @samp{Mule} menus.  For
detailed descriptions of these menus, @ref{Pull-down Menus}.  (In 21.2
SXEmacsen, the @samp{Mule} menu will be moved under @samp{Options}.)

@node Scrollbar Basics, Mode Line Basics, Menubar Basics, GUI Components
@comment  node-name,  next,  previous,  up
@section SXEmacs Scrollbars

SXEmacs scrollbars provide the usual interface.  Arrow buttons at either
end allow for line by line scrolling, including autorepeat.  Clicking in
the scrollbar itself provides scrolling by windowsfull, depending on
which side of the slider is clicked.  The slider itself may be dragged
for smooth scrolling.

The position of the slider corresponds to the position of the window in
the buffer.  In particular, the length of the slider is proportional to
the fraction of the buffer which appears in the window.

The presence of the scrollbars is under control of the application or
may be customized by the user.  By default a vertical scrollbar is
present in all windows (except the minibuffer), and there is no
horizontal scrollbar.

@node Mode Line Basics, Toolbar Basics, Scrollbar Basics, GUI Components
@comment  node-name,  next,  previous,  up
@section SXEmacs Mode Lines

When used in a windowing system, the SXEmacs modelines can be dragged
vertically. The effect is to resize the windows above and below the
modeline (this includes the minibuffer window).

Additionally, a modeline can be dragged horizontally, in which case it
scrolls its own text. This behavior is not enabled by default because it
could be considered as disturbing when dragging vertically. When this
behavior is enabled, the modeline's text can be dragged either in the
same direction as the mouse, or in the opposite sense, making the
modeline act as a scrollbar for its own text.

You can select the behavior you want from the @samp{Display} submenu of
the @samp{Options} menu.

@node Toolbar Basics, Gutter Basics, Mode Line Basics, GUI Components
@comment  node-name,  next,  previous,  up
@section SXEmacs Toolbars

SXEmacs has a default toolbar which provides shortcuts for some of the
commonly used operations (such as opening files) and applications (such
as the Info manual reader).  Operations which require arguments will pop
up dialogs to get them.

The position of the default toolbar can be customized.  Also, several
toolbars may be present simultaneously (in different positions).  VM,
for example, provides an application toolbar which shortcuts for
mail-specific operations like sending, saving, and deleting messages.

@node Gutter Basics, Inhibiting, Toolbar Basics, GUI Components
@comment  node-name,  next,  previous,  up
@section SXEmacs Gutters

Gutters are the most flexible of the GUI components described in this
section.  In theory, the other GUI components could be implemented by
customizing a gutter, but in practice the other components were
introduced earlier and have their own special implementations.  Gutters
tend to be more transient than the other components.  Buffer tabs, for
example, change every time the selected buffer in the frame changes.
And for progress gauges a gutter to contain the gauge is typically
created on the fly when needed, then destroyed when the operation whose
staus is being displayed is completed.

Buffer tabs, having somewhat complex behavior, deserve a closer look.
By default, a row of buffer tabs is displayed at the top of every frame.
(The tabs could be placed in the bottom gutter, but would be oriented
the same way and look rather odd.  The horizontal orientation makes
putting them in a side gutter utterly impractical.)  The buffer
displayed in the current window of a frame can be changed to a specific
buffer by clicking [mouse-1] on the corresponding tab in the gutter.

Each tab contains the name of its buffer.  The tab for the current
buffer in each frame is displayed in raised relief.  The list of buffers
chosen for display in the buffer tab row is derived by filtering the
buffer list (like the @code{Buffers} menu).  The list starts out with
all existing buffers, with more recently selected buffers coming earlier
in the list.

Then "uninteresting" buffers, like internal SXEmacs buffers, the
@code{*Message Log*} buffer, and so on are deleted from the list.  Next,
the frame's selected buffer is determined.  Buffers with a different
major mode from the selected buffer are removed from the list.  Finally,
if the list is too long, the least recently used buffers are deleted
from the list.  By default up to 6 most recently used buffers with the
same mode are displayed on tabs in the gutter.

This behavior can be altered by customizing
@code{buffers-tab-filter-functions}.  Setting this variable to
@code{nil} forces display of all buffers, up to
@code{buffers-tab-max-size} (also customizable).  More complex behavior
may be available in 3rd party libraries.  These, and some more
rarely customized options, are in the @code{buffers-tab} Customize group.

@node Inhibiting, Customizing, Gutter Basics, GUI Components
@comment  node-name,  next,  previous,  up
@section Inhibiting Display of GUI Components

Use of GUI facilities is a personal thing.  Almost everyone agrees that
drawing via keyboard-based "turtle graphics" is acceptable to hardly
anyone if a mouse is available, but conversely emulating a keyboard with
a screenful of buttons is a painful experience.  But between those
extremes the complete novice will require a fair amount of time before
toolbars and menus become dispensable, but many an "Ancien Haquer" sees
them as a complete waste of precious frame space that could be filled
with text.

Display of all of the GUI components created by SXEmacs can be inhibited
through the use of Customize.  Customize can be accessed through
@samp{Options | Customize} in the menu bar, or via @kbd{M-x customize}.
Then navigate through the Customize tree to @samp{Emacs | Environment}.
Scrollbar and toolbar visibility is controlled via the @samp{Display}
group, options @samp{Scrollbars visible} and  @samp{Toolbar visible}
respectively.  Gutter visibility is controlled by group @samp{Gutter},
option @samp{Visible}.

Or they can be controlled directly by @kbd{M-x customize-variable}, by
changing the values of the variables @code{menubar-visible-p},
@code{scrollbars-visible-p}, @code{toolbar-visible-p}, or
@code{gutter-buffers-tab-visible-p} respectively.  (The strange form of
the last variable is due to the fact that gutters are often used to
display transient widgets like progress gauges, which you probably don't
want to inhibit.  It is more likely that you want to inhibit the default
display of the buffers tab widget, which is what that variable controls.
This interface is subject to change depending on developer experience
and user feedback.)

Control of frame configuration can controlled automatically according to
various parameters such as buffer or frame because these are
@dfn{specifiers} @ref{Specifiers, , , lispref}.  Using these features
requires programming in Lisp; Customize is not yet that sophisticated.
Also, components that appear in various positions and orientations can
have display suppressed according to position.  @kbd{C-h a visible-p}
gives a list of variables which can be customized.  E.g., to control the
visibility of specifically the left-side toolbar only, customize
@code{left-toolbar-visible-p}.

@node Customizing, , Inhibiting, GUI Components
@comment  node-name,  next,  previous,  up
@section Changing the Position, Orientation, and Appearance of GUI Components

  #### Not documented yet.

@node SXEmacs under X, , GUI Components, Frame
@section Using SXEmacs Under the X Window System
@comment  node-name,  next,  previous,  up

SXEmacs 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 SXEmacs 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 SXEmacs frame)
has a menu bar for mouse-controlled operations (@pxref{Pull-down Menus}).

@cindex multi-frame SXEmacs
@findex make-frame
SXEmacs under X is also a multi-frame SXEmacs.  You can use the @b{New
Frame} menu item from the @b{File} menu to create a new SXEmacs 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
@vindex default-frame-plist
You can specify a different default frame size other than the one provided.
Use the variable @code{default-frame-plist}, which is a plist 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-plist '(width 80 height 55))
@end example

This variable has replaced @code{default-frame-alist}, which is
considered obsolete.

@vindex x-frame-defaults
For values specific to the first SXEmacs 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