doc/emacs trivia

[gnu-emacs] / doc / emacs / frames.texi

@c This is part of the Emacs manual.
@c Copyright (C) 1985-1987, 1993-1995, 1997, 1999-2012
@c   Free Software Foundation, Inc.
@c See file emacs.texi for copying conditions.
@node Frames, International, Windows, Top
@chapter Frames and Graphical Displays
@cindex frames

  When Emacs is started on a graphical display, e.g.@: on the X Window
System, it occupies a graphical system-level ``window''.  In this
manual, we call this a @dfn{frame}, reserving the word ``window'' for
the part of the frame used for displaying a buffer.  A frame initially
contains one window, but it can be subdivided into multiple windows
(@pxref{Windows}).  A frame normally also contains a menu bar, tool
bar, and echo area.

  You can also create additional frames (@pxref{Creating Frames}).
All frames created in the same Emacs session have access to the same
underlying buffers and other data.  For instance, if a buffer is being
shown in more than one frame, any changes made to it in one frame show
up immediately in the other frames too.

  Typing @kbd{C-x C-c} closes all the frames on the current display,
and ends the Emacs session if it has no frames open on any other
displays (@pxref{Exiting}).  To close just the selected frame, type
@kbd{C-x 5 0} (that is zero, not @kbd{o}).

  This chapter describes Emacs features specific to graphical displays
(particularly mouse commands), and features for managing multiple
frames.  On text-only terminals, many of these features are
unavailable.  However, it is still possible to create multiple
``frames'' on text-only terminals; such frames are displayed one at a
time, filling the entire terminal screen (@pxref{Non-Window
Terminals}).  It is also possible to use the mouse on some text-only
terminals (@pxref{Text-Only Mouse}, for doing so on GNU and Unix
systems; and
@iftex
@pxref{MS-DOS Mouse,,,emacs-xtra,Specialized Emacs Features},
@end iftex
@ifnottex
@pxref{MS-DOS Mouse},
@end ifnottex
for doing so on MS-DOS).

@menu
* Mouse Commands::      Moving, cutting, and pasting, with the mouse.
* Word and Line Mouse:: Mouse commands for selecting whole words or lines.
* Mouse References::    Using the mouse to select an item from a list.
* Menu Mouse Clicks::   Mouse clicks that bring up menus.
* Mode Line Mouse::     Mouse clicks on the mode line.
* Creating Frames::     Creating additional Emacs frames with various contents.
* Frame Commands::      Iconifying, deleting, and switching frames.
* Fonts::               Changing the frame font.
* Speedbar::            How to make and use a speedbar frame.
* Multiple Displays::   How one Emacs instance can talk to several displays.
* Frame Parameters::    Changing the colors and other modes of frames.
* Scroll Bars::         How to enable and disable scroll bars; how to use them.
* Drag and Drop::       Using drag and drop to open files and insert text.
* Menu Bars::           Enabling and disabling the menu bar.
* Tool Bars::           Enabling and disabling the tool bar.
* Dialog Boxes::        Controlling use of dialog boxes.
* Tooltips::            Displaying information at the current mouse position.
* Mouse Avoidance::     Preventing the mouse pointer from obscuring text.
* Non-Window Terminals::  Multiple frames on terminals that show only one.
* Text-Only Mouse::     Using the mouse in text-only terminals.
@end menu

@node Mouse Commands
@section Mouse Commands for Editing
@cindex mouse buttons (what they do)

@kindex Mouse-1
@kindex Mouse-2
@kindex Mouse-3
@table @kbd
@item Mouse-1
Move point to where you click (@code{mouse-set-point}).

@item Drag-Mouse-1
Activate the region around the text selected by dragging, and copy it
to the kill ring (@code{mouse-set-region}).

@item Mouse-2
Yank the last killed text at the click position
(@code{mouse-yank-at-click}).

@item Mouse-3
If the region is active, move the nearer end of the region to the
click position; otherwise, set mark at the current value of point and
point at the click position.  Save the resulting region in the kill
ring; on a second click, kill it (@code{mouse-save-then-kill}).
@end table

@findex mouse-set-point
  The most basic mouse command is @code{mouse-set-point}, which is
invoked by clicking with the left mouse button, @kbd{Mouse-1}, in the
text area of a window.  This moves point to the position where you
clicked.  If that window was not the selected window, it becomes the
selected window.

@vindex x-mouse-click-focus-ignore-position
  Normally, if the frame you clicked in was not the selected frame, it
is made the selected frame, in addition to selecting the window and
setting the cursor.  On the X Window System, you can change this by
setting the variable @code{x-mouse-click-focus-ignore-position} to
@code{t}.  In that case, the initial click on an unselected frame just
selects the frame, without doing anything else; clicking again selects
the window and sets the cursor position.

@findex mouse-set-region
  Holding down @kbd{Mouse-1} and ``dragging'' the mouse over a stretch
of text activates the region around that text
(@code{mouse-set-region}), placing the mark where you started holding
down the mouse button, and point where you release it (@pxref{Mark}).
In addition, the text in the region becomes the primary selection
(@pxref{Primary Selection}).

@vindex mouse-drag-copy-region
  If you change the variable @code{mouse-drag-copy-region} to a
non-@code{nil} value, dragging the mouse over a stretch of text also
adds the text to the kill ring.  The default is @code{nil}.

@vindex mouse-scroll-min-lines
  If you move the mouse off the top or bottom of the window while
dragging, the window scrolls at a steady rate until you move the mouse
back into the window.  This way, you can select regions that don't fit
entirely on the screen.  The number of lines scrolled per step depends
on how far away from the window edge the mouse has gone; the variable
@code{mouse-scroll-min-lines} specifies a minimum step size.

@findex mouse-yank-primary
@findex mouse-yank-at-click
  Clicking with the middle mouse button, @kbd{Mouse-2}, moves point to
the position where you clicked and inserts the contents of the primary
selection (@code{mouse-yank-primary}).  @xref{Primary Selection}.
This behavior is consistent with other X applications.  Alternatively,
you can rebind @kbd{Mouse-2} to @code{mouse-yank-at-click}, which
performs a yank at point.

@vindex mouse-yank-at-point
  If you change the variable @code{mouse-yank-at-point} to a
non-@code{nil} value, @kbd{Mouse-2} does not move point; it inserts
the text at point, regardless of where you clicked or even which of
the frame's windows you clicked on.  This variable affects both
@code{mouse-yank-primary} and @code{mouse-yank-at-click}.

@findex mouse-save-then-kill
  Clicking with the right mouse button, @kbd{Mouse-3}, runs the
command @code{mouse-save-then-kill}.  This performs several actions
depending on where you click and the status of the region:

@itemize @bullet
@item
If no region is active, clicking @kbd{Mouse-3} activates the region,
placing the mark where point was and point at the clicked position.

@item
If a region is active, clicking @kbd{Mouse-3} adjusts the nearer end
of the region by moving it to the clicked position.  The adjusted
region's text is copied to the kill ring; if the text in the original
region was already on the kill ring, it replaces it there.

@item
If you originally specified the region using a double or triple
@kbd{Mouse-1}, so that the region is defined to consist of entire
words or lines (@pxref{Word and Line Mouse}), then adjusting the
region with @kbd{Mouse-3} also proceeds by entire words or lines.

@item
If you use @kbd{Mouse-3} a second time consecutively, at the same
place, that kills the region already selected.  Thus, the simplest way
to kill text with the mouse is to click @kbd{Mouse-1} at one end, then
click @kbd{Mouse-3} twice at the other end.  To copy the text into the
kill ring without deleting it from the buffer, press @kbd{Mouse-3}
just once---or just drag across the text with @kbd{Mouse-1}.  Then you
can copy it elsewhere by yanking it.
@end itemize

  The @code{mouse-save-then-kill} command also obeys the variable
@code{mouse-drag-copy-region} (described above).  If the value is
non-@code{nil}, then whenever the command sets or adjusts the active
region, the text in the region is also added to the kill ring.  If the
latest kill ring entry had been added the same way, that entry is
replaced rather than making a new entry.

  Whenever you set the region using any of the mouse commands
described above, the mark will be deactivated by any subsequent
unshifted cursor motion command, in addition to the usual ways of
deactivating the mark.  @xref{Shift Selection}.

@cindex mouse wheel
@findex mouse-wheel-mode
@cindex Mouse Wheel minor mode
@cindex mode, Mouse Wheel
@vindex mouse-wheel-follow-mouse
@vindex mouse-wheel-scroll-amount
@vindex mouse-wheel-progressive-speed
  Some mice have a ``wheel'' which can be used for scrolling.  Emacs
supports scrolling windows with the mouse wheel, by default, on most
graphical displays.  To toggle this feature, use @kbd{M-x
mouse-wheel-mode}.  The variables @code{mouse-wheel-follow-mouse} and
@code{mouse-wheel-scroll-amount} determine where and by how much
buffers are scrolled.  The variable
@code{mouse-wheel-progressive-speed} determines whether the scroll
speed is linked to how fast you move the wheel.

@node Word and Line Mouse
@section Mouse Commands for Words and Lines

  These variants of @kbd{Mouse-1} select entire words or lines at a
time.  Emacs activates the region around the selected text, which is
also copied to the kill ring.

@table @kbd
@item Double-Mouse-1
Select the text around the word which you click on.

Double-clicking on a character with ``symbol'' syntax (such as
underscore, in C mode) selects the symbol surrounding that character.
Double-clicking on a character with open- or close-parenthesis syntax
selects the parenthetical grouping which that character starts or
ends.  Double-clicking on a character with string-delimiter syntax
(such as a single-quote or double-quote in C) selects the string
constant (Emacs uses heuristics to figure out whether that character
is the beginning or the end of it).

@item Double-Drag-Mouse-1
Select the text you drag across, in the form of whole words.

@item Triple-Mouse-1
Select the line you click on.

@item Triple-Drag-Mouse-1
Select the text you drag across, in the form of whole lines.
@end table

@node Mouse References
@section Following References with the Mouse
@kindex Mouse-1 @r{(selection)}
@kindex Mouse-2 @r{(selection)}
@cindex hyperlinks
@cindex links
@cindex text buttons
@cindex buttons

@vindex mouse-highlight
  Some Emacs buffers include @dfn{buttons}, or @dfn{hyperlinks}:
pieces of text that perform some action (e.g.@: following a reference)
when activated (e.g.@: by clicking on them).  Usually, a button's text
is visually highlighted: it is underlined, or a box is drawn around
it.  If you move the mouse over a button, the shape of the mouse
cursor changes and the button lights up.  If you change the variable
@code{mouse-highlight} to @code{nil}, Emacs disables this
highlighting.

  You can activate a button by moving point to it and typing
@key{RET}, or by clicking either @kbd{Mouse-1} or @kbd{Mouse-2} on the
button.  For example, in a Dired buffer, each file name is a button;
activating it causes Emacs to visit that file (@pxref{Dired}).  In a
@file{*Compilation*} buffer, each error message is a button, and
activating it visits the source code for that error
(@pxref{Compilation}).

  Although clicking @kbd{Mouse-1} on a button usually activates the
button, if you hold the mouse button down for a period of time before
releasing it (specifically, for more than 450 milliseconds), then
Emacs moves point where you clicked, without activating the button.
In this way, you can use the mouse to move point over a button without
activating it.  Dragging the mouse over or onto a button has its usual
behavior of setting the region, and does not activate the button.

  You can change how @kbd{Mouse-1} applies to buttons by customizing
the variable @code{mouse-1-click-follows-link}.  If the value is a
positive integer, that determines how long you need to hold the mouse
button down for, in milliseconds, to cancel button activation; the
default is 450, as described in the previous paragraph.  If the value
is @code{nil}, @kbd{Mouse-1} just sets point where you clicked, and
does not activate buttons.  If the value is @code{double}, double
clicks activate buttons but single clicks just set point.

@vindex mouse-1-click-in-non-selected-windows
  Normally, @kbd{Mouse-1} on a button activates the button even if it
is in a non-selected window.  If you change the variable
@code{mouse-1-click-in-non-selected-windows} to @code{nil},
@kbd{Mouse-1} on a button in an unselected window moves point to the
clicked position and selects that window, without activating the
button.

@node Menu Mouse Clicks
@section Mouse Clicks for Menus

  Several mouse clicks with the @key{CTRL} and @key{SHIFT} modifiers
bring up menus.

@table @kbd
@item C-Mouse-1
@kindex C-Mouse-1
This menu is for selecting a buffer.

The MSB (``mouse select buffer'') global minor mode makes this
menu smarter and more customizable.  @xref{Buffer Menus}.

@item C-Mouse-2
@kindex C-Mouse-2
This menu contains entries for examining faces and other text
properties, and well as for setting them (the latter is mainly useful
when editing enriched text; @pxref{Enriched Text}).

@item C-Mouse-3
@kindex C-Mouse-3
This menu is mode-specific.  For most modes if Menu-bar mode is on,
this menu has the same items as all the mode-specific menu-bar menus
put together.  Some modes may specify a different menu for this
button.  If Menu Bar mode is off, this menu contains all the items
which would be present in the menu bar---not just the mode-specific
ones---so that you can access them without having to display the menu
bar.

@item S-Mouse-1
This menu is for changing the default face within the window's buffer.
@xref{Text Scale}.
@end table

  Some graphical applications use @kbd{Mouse-3} for a mode-specific
menu.  If you prefer @kbd{Mouse-3} in Emacs to bring up such a menu
instead of running the @code{mouse-save-then-kill} command, rebind
@kbd{Mouse-3} by adding the following line to your init file
(@pxref{Init Rebinding}):

@smallexample
(global-set-key [mouse-3] 'mouse-popup-menubar-stuff)
@end smallexample

@node Mode Line Mouse
@section Mode Line Mouse Commands
@cindex mode line, mouse
@cindex mouse on mode line

  You can use mouse clicks on window mode lines to select and manipulate
windows.

  Some areas of the mode line, such as the buffer name, and major and minor
mode names, have their own special mouse bindings.  These areas are
highlighted when you hold the mouse over them, and information about
the special bindings will be displayed (@pxref{Tooltips}).  This
section's commands do not apply in those areas.

@table @kbd
@item Mouse-1
@kindex Mouse-1 @r{(mode line)}
@kbd{Mouse-1} on a mode line selects the window it belongs to.  By
dragging @kbd{Mouse-1} on the mode line, you can move it, thus
changing the height of the windows above and below.  Changing heights
with the mouse in this way never deletes windows, it just refuses to
make any window smaller than the minimum height.

@item Mouse-2
@kindex Mouse-2 @r{(mode line)}
@kbd{Mouse-2} on a mode line expands that window to fill its frame.

@item Mouse-3
@kindex Mouse-3 @r{(mode line)}
@kbd{Mouse-3} on a mode line deletes the window it belongs to.  If the
frame has only one window, it does nothing.

@item C-Mouse-2
@kindex C-mouse-2 @r{(mode line)}
@kbd{C-Mouse-2} on a mode line splits that window, producing two
side-by-side windows with the boundary running through the click
position (@pxref{Split Window}).
@end table

@kindex Mouse-1 @r{(scroll bar)}
  Furthermore, by clicking and dragging @kbd{Mouse-1} on the divider
between two side-by-side mode lines, you can move the vertical
boundary to the left or right.

@node Creating Frames
@section Creating Frames
@cindex creating frames

@kindex C-x 5
  The prefix key @kbd{C-x 5} is analogous to @kbd{C-x 4}.  Whereas
each @kbd{C-x 4} command pops up a buffer in a different window in the
selected frame (@pxref{Pop Up Window}), the @kbd{C-x 5} commands use a
different frame.  If an existing visible or iconified (``minimized'')
frame already displays the requested buffer, that frame is raised and
deiconified (``un-minimized''); otherwise, a new frame is created on
the current display terminal.

  The various @kbd{C-x 5} commands differ in how they find or create the
buffer to select:

@table @kbd
@item C-x 5 2
@kindex C-x 5 2
@findex make-frame-command
Create a new frame (@code{make-frame-command}).
@item C-x 5 b @var{bufname} @key{RET}
Select buffer @var{bufname} in another frame.  This runs
@code{switch-to-buffer-other-frame}.
@item C-x 5 f @var{filename} @key{RET}
Visit file @var{filename} and select its buffer in another frame.  This
runs @code{find-file-other-frame}.  @xref{Visiting}.
@item C-x 5 d @var{directory} @key{RET}
Select a Dired buffer for directory @var{directory} in another frame.
This runs @code{dired-other-frame}.  @xref{Dired}.
@item C-x 5 m
Start composing a mail message in another frame.  This runs
@code{mail-other-frame}.  It is the other-frame variant of @kbd{C-x m}.
@xref{Sending Mail}.
@item C-x 5 .
Find a tag in the current tag table in another frame.  This runs
@code{find-tag-other-frame}, the multiple-frame variant of @kbd{M-.}.
@xref{Tags}.
@item C-x 5 r @var{filename} @key{RET}
@kindex C-x 5 r
@findex find-file-read-only-other-frame
Visit file @var{filename} read-only, and select its buffer in another
frame.  This runs @code{find-file-read-only-other-frame}.
@xref{Visiting}.
@end table

  You can control the appearance and behavior of the newly-created
frames by specifying @dfn{frame parameters}.  @xref{Frame Parameters}.

@node Frame Commands
@section Frame Commands

  The following commands are used to delete and operate on frames:

@table @kbd
@item C-x 5 0
@kindex C-x 5 0
@findex delete-frame
Delete the selected frame (@code{delete-frame}).  This signals an
error if there is only one frame.

@item C-z
@kindex C-z @r{(X windows)}
@findex suspend-frame
Minimize (or ``iconify) the selected Emacs frame
(@code{suspend-frame}).  @xref{Exiting}.

@item C-x 5 o
@kindex C-x 5 o
@findex other-frame
Select another frame, and raise it.  If you repeat this command, it
cycles through all the frames on your terminal.

@item C-x 5 1
@kindex C-x 5 1
@findex delete-other-frames
Delete all frames on the current terminal, except the selected one.
@end table

  The @kbd{C-x 5 0} (@code{delete-frame}) command deletes the selected
frame.  However, it will refuse to delete the last frame in an Emacs
session, to prevent you from losing the ability to interact with the
Emacs session.  Note that when Emacs is run as a daemon (@pxref{Emacs
Server}), there is always a ``virtual frame'' that remains after all
the ordinary, interactive frames are deleted.  In this case, @kbd{C-x
5 0} can delete the last interactive frame; you can use
@command{emacsclient} to reconnect to the Emacs session.

  The @kbd{C-x 5 1} (@code{delete-other-frames}) command deletes all
other frames on the current terminal (this terminal refers to either a
graphical display, or a text-only terminal; @pxref{Non-Window
Terminals}).  If the Emacs session has frames open on other graphical
displays or text terminals, those are not deleted.

@vindex focus-follows-mouse
  The @kbd{C-x 5 o} (@code{other-frame}) command selects the next
frame on the current terminal.  If you are using Emacs on the X Window
System with a window manager that selects (or @dfn{gives focus to})
whatever frame the mouse cursor is over, you have to change the
variable @code{focus-follows-mouse} to @code{t} in order for this
command to work properly.  Then invoking @kbd{C-x 5 o} will also warp
the mouse cursor to the chosen frame.

@node Fonts
@section Fonts
@cindex fonts

  By default, Emacs displays text on graphical displays using a
12-point monospace font.  There are several different ways to specify
a different font:

@itemize
@item
Click on @samp{Set Default Font} in the @samp{Options} menu.  To save
this for future sessions, click on @samp{Save Options} in the
@samp{Options} menu.

@item
Add a line to your init file (@pxref{Init File}), modifying the
variable @code{default-frame-alist} to specify the @code{font}
parameter (@pxref{Creating Frames}), like this:

@smallexample
(add-to-list 'default-frame-alist '(font . "DejaVu Sans Mono-10"))
@end smallexample

@cindex X defaults file
@cindex X resources file
@item
Add an @samp{emacs.font} X resource setting to your X resource file,
like this:

@smallexample
emacs.font: DejaVu Sans Mono-12
@end smallexample

@noindent
You must restart X, or use the @command{xrdb} command, for the X
resources file to take effect.  @xref{Resources}.  When specifying a
font in your X resources file, you should not quote it.

@item
If you are running Emacs on the GNOME desktop, you can tell Emacs to
use the default system font by setting the variable
@code{font-use-system-font} to @code{t} (the default is @code{nil}).
For this to work, Emacs must have been compiled with Gconf support.

@item
Use the command line option @samp{-fn} (or @samp{--font}).  @xref{Font
X}.
@end itemize

  To check what font you're currently using, the @kbd{C-u C-x =}
command can be helpful.  It describes the character at point, and
names the font that it's rendered in.

@cindex fontconfig
  On X, there are four different ways to express a ``font name''.  The
first is to use a @dfn{Fontconfig pattern}.  Fontconfig patterns have
the following form:

@smallexample
@var{fontname}[-@var{fontsize}][:@var{name1}=@var{values1}][:@var{name2}=@var{values2}]...
@end smallexample

@noindent
Within this format, any of the elements in braces may be omitted.
Here, @var{fontname} is the @dfn{family name} of the font, such as
@samp{Monospace} or @samp{DejaVu Sans Mono}; @var{fontsize} is the
@dfn{point size} of the font (one @dfn{printer's point} is about 1/72
of an inch); and the @samp{@var{name}=@var{values}} entries specify
settings such as the slant and weight of the font.  Each @var{values}
may be a single value, or a list of values separated by commas.  In
addition, some property values are valid with only one kind of
property name, in which case the @samp{@var{name}=} part may be
omitted.

Here is a list of common font properties:

@table @samp
@item slant
One of @samp{italic}, @samp{oblique}, or @samp{roman}.

@item weight
One of @samp{light}, @samp{medium}, @samp{demibold}, @samp{bold} or
@samp{black}.

@item style
Some fonts define special styles which are a combination of slant and
weight.  For instance, @samp{Dejavu Sans} defines the @samp{book}
style, which overrides the slant and weight properties.

@item width
One of @samp{condensed}, @samp{normal}, or @samp{expanded}.

@item spacing
One of @samp{monospace}, @samp{proportional}, @samp{dual-width}, or
@samp{charcell}.
@end table

@noindent
Here are some examples of Fontconfig patterns:

@smallexample
Monospace
Monospace-12
Monospace-12:bold
DejaVu Sans Mono:bold:italic
Monospace-12:weight=bold:slant=italic
@end smallexample

For a more detailed description of Fontconfig patterns, see the
Fontconfig manual, which is distributed with Fontconfig and available
online at @url{http://fontconfig.org/fontconfig-user.html}.

@cindex GTK font pattern
  The second way to specify a font is to use a @dfn{GTK font pattern}.
These have the syntax

@smallexample
@var{fontname} [@var{properties}] [@var{fontsize}]
@end smallexample

@noindent
where @var{fontname} is the family name, @var{properties} is a list of
property values separated by spaces, and @var{fontsize} is the point
size.  The properties that you may specify for GTK font patterns are
as follows:

@itemize
@item
Slant properties: @samp{Italic} or @samp{Oblique}.  If omitted, the
default (roman) slant is implied.
@item
Weight properties: @samp{Bold}, @samp{Book}, @samp{Light},
@samp{Medium}, @samp{Semi-bold}, or @samp{Ultra-light}.  If omitted,
@samp{Medium} weight is implied.
@item
Width properties: @samp{Semi-Condensed} or @samp{Condensed}.  If
omitted, a default width is used.
@end itemize

@noindent
Here are some examples of GTK font patterns:

@smallexample
Monospace 12
Monospace Bold Italic 12
@end smallexample

@cindex XLFD
@cindex X Logical Font Description
  The third way to specify a font is to use an @dfn{XLFD} (@dfn{X
Logical Font Description}).  This is the traditional method for
specifying fonts under X.  Each XLFD consists of fourteen words or
numbers, separated by dashes, like this:

@smallexample
-misc-fixed-medium-r-semicondensed--13-*-*-*-c-60-iso8859-1
@end smallexample

@noindent
A wildcard character (@samp{*}) in an XLFD matches any sequence of
characters (including none), and @samp{?} matches any single
character.  However, matching is implementation-dependent, and can be
inaccurate when wildcards match dashes in a long name.  For reliable
results, supply all 14 dashes and use wildcards only within a field.
Case is insignificant in an XLFD.  The syntax for an XLFD is as
follows:

@smallexample
-@var{maker}-@var{family}-@var{weight}-@var{slant}-@var{widthtype}-@var{style}@dots{}
@dots{}-@var{pixels}-@var{height}-@var{horiz}-@var{vert}-@var{spacing}-@var{width}-@var{registry}-@var{encoding}
@end smallexample

@noindent
The entries have the following meanings:

@table @var
@item maker
The name of the font manufacturer.
@item family
The name of the font family (e.g.@: @samp{courier}).
@item weight
The font weight---normally either @samp{bold}, @samp{medium} or
@samp{light}.  Some font names support other values.
@item slant
The font slant---normally @samp{r} (roman), @samp{i} (italic),
@samp{o} (oblique), @samp{ri} (reverse italic), or @samp{ot} (other).
Some font names support other values.
@item widthtype
The font width---normally @samp{normal}, @samp{condensed},
@samp{extended}, or @samp{semicondensed} (some font names support
other values).
@item style
An optional additional style name.  Usually it is empty---most XLFDs
have two hyphens in a row at this point.
@item pixels
The font height, in pixels.
@item height
The font height on the screen, measured in tenths of a printer's
point.  This is the point size of the font, times ten.  For a given
vertical resolution, @var{height} and @var{pixels} are proportional;
therefore, it is common to specify just one of them and use @samp{*}
for the other.
@item horiz
The horizontal resolution, in pixels per inch, of the screen for which
the font is intended.
@item vert
The vertical resolution, in pixels per inch, of the screen for which
the font is intended.  Normally the resolution of the fonts on your
system is the right value for your screen; therefore, you normally
specify @samp{*} for this and @var{horiz}.
@item spacing
This is @samp{m} (monospace), @samp{p} (proportional) or @samp{c}
(character cell).
@item width
The average character width, in pixels, multiplied by ten.
@item registry
@itemx encoding
The X font character set that the font depicts.  (X font character
sets are not the same as Emacs character sets, but they are similar.)
You can use the @command{xfontsel} program to check which choices you
have.  Normally you should use @samp{iso8859} for @var{registry} and
@samp{1} for @var{encoding}.
@end table

  The fourth and final method of specifying a font is to use a ``font
nickname''.  Certain fonts have shorter nicknames, which you can use
instead of a normal font specification.  For instance, @samp{6x13} is
equivalent to

@smallexample
-misc-fixed-medium-r-semicondensed--13-*-*-*-c-60-iso8859-1
@end smallexample

@cindex client-side fonts
@cindex server-side fonts
  On X, Emacs recognizes two types of fonts: @dfn{client-side} fonts,
which are provided by the Xft and Fontconfig libraries, and
@dfn{server-side} fonts, which are provided by the X server itself.
Most client-side fonts support advanced font features such as
antialiasing and subpixel hinting, while server-side fonts do not.
Fontconfig and GTK patterns match only client-side fonts.

@cindex listing system fonts
  You will probably want to use a fixed-width default font---that is,
a font in which all characters have the same width.  For Xft and
Fontconfig fonts, you can use the @command{fc-list} command to list
the available fixed-width fonts, like this:

@example
fc-list :spacing=mono fc-list :spacing=charcell
@end example

@noindent
For server-side X fonts, you can use the @command{xlsfonts} program to
list the available fixed-width fonts, like this:

@example
xlsfonts -fn '*x*' | egrep "^[0-9]+x[0-9]+"
xlsfonts -fn '*-*-*-*-*-*-*-*-*-*-*-m*'
xlsfonts -fn '*-*-*-*-*-*-*-*-*-*-*-c*'
@end example

@noindent
Any font with @samp{m} or @samp{c} in the @var{spacing} field of the
XLFD is a fixed-width font.  To see what a particular font looks like,
use the @command{xfd} command.  For example:

@example
xfd -fn 6x13
@end example

@noindent
displays the entire font @samp{6x13}.

  While running Emacs, you can also set the font of a specific kind of
text (@pxref{Faces}), or a particular frame (@pxref{Frame
Parameters}).

@node Speedbar
@section Speedbar Frames
@cindex speedbar

@cindex attached frame (of speedbar)
  The @dfn{speedbar} is a special frame for conveniently navigating in
or operating on another frame.  The speedbar, when it exists, is
always associated with a specific frame, called its @dfn{attached
frame}; all speedbar operations act on that frame.

  Type @kbd{M-x speedbar} to create the speedbar and associate it with
the current frame.  To dismiss the speedbar, type @kbd{M-x speedbar}
again, or select the speedbar and type @kbd{q}.  (You can also delete
the speedbar frame like any other Emacs frame.)  If you wish to
associate the speedbar with a different frame, dismiss it and call
@kbd{M-x speedbar} from that frame.

  The speedbar can operate in various modes.  Its default mode is
@dfn{File Display} mode, which shows the files in the current
directory of the selected window of the attached frame, one file per
line.  Clicking on a file name visits that file in the selected window
of the attached frame, and clicking on a directory name shows that
directory in the speedbar (@pxref{Mouse References}).  Each line also
has a box, @samp{[+]} or @samp{<+>}, that you can click on to
@dfn{expand} the contents of that item.  Expanding a directory adds
the contents of that directory to the speedbar display, underneath the
directory's own line.  Expanding an ordinary file adds a list of the
tags in that file to the speedbar display; you can click on a tag name
to jump to that tag in the selected window of the attached frame.
When a file or directory is expanded, the @samp{[+]} changes to
@samp{[-]}; you can click on that box to @dfn{contract} the item,
hiding its contents.

  You navigate through the speedbar using the keyboard, too.  Typing
@kbd{RET} while point is on a line in the speedbar is equivalent to
clicking the item on the current line, and @kbd{SPC} expands or
contracts the item.  @kbd{U} displays the parent directory of the
current directory.  To copy, delete, or rename the file on the current
line, type @kbd{C}, @kbd{D}, and @kbd{R} respectively.  To create a
new directory, type @kbd{M}.

  Another general-purpose speedbar mode is @dfn{Buffer Display} mode;
in this mode, the speedbar displays a list of Emacs buffers.  To
switch to this mode, type @kbd{b} in the speedbar.  To return to File
Display mode, type @kbd{f}.  You can also change the display mode by
clicking @kbd{mouse-3} anywhere in the speedbar window (or
@kbd{mouse-1} on the mode-line) and selecting @samp{Displays} in the
pop-up menu.

  Some major modes, including Rmail mode, Info, and GUD, have
specialized ways of putting useful items into the speedbar for you to
select.  For example, in Rmail mode, the speedbar shows a list of Rmail
files, and lets you move the current message to another Rmail file by
clicking on its @samp{<M>} box.

  For more details on using and programming the speedbar, @xref{Top,
Speedbar,,speedbar, Speedbar Manual}.

@node Multiple Displays
@section Multiple Displays
@cindex multiple displays

  A single Emacs can talk to more than one X display.  Initially, Emacs
uses just one display---the one specified with the @env{DISPLAY}
environment variable or with the @samp{--display} option (@pxref{Initial
Options}).  To connect to another display, use the command
@code{make-frame-on-display}:

@findex make-frame-on-display
@table @kbd
@item M-x make-frame-on-display @key{RET} @var{display} @key{RET}
Create a new frame on display @var{display}.
@end table

  A single X server can handle more than one screen.  When you open
frames on two screens belonging to one server, Emacs knows they share a
single keyboard, and it treats all the commands arriving from these
screens as a single stream of input.

  When you open frames on different X servers, Emacs makes a separate
input stream for each server.  Each server also has its own selected
frame.  The commands you enter with a particular X server apply to
that server's selected frame.

@node Frame Parameters
@section Frame Parameters
@cindex default-frame-alist

  You can control the default appearance and behavior of all frames by
specifying a default list of @dfn{frame parameters} in the variable
@code{default-frame-alist}.  Its value should be a list of entries,
each specifying a parameter name and a value for that parameter.
These entries take effect whenever Emacs creates a new frame,
including the initial frame.

@cindex frame size, specifying default
  For example, you can add the following lines to your init file
(@pxref{Init File}) to set the default frame width to 90 character
columns, the default frame height to 40 character rows, and the
default font to @samp{Monospace-10}:

@example
(add-to-list 'default-frame-alist '(width  . 90))
(add-to-list 'default-frame-alist '(height . 40))
(add-to-list 'default-frame-alist '(font . "Monospace-10"))
@end example

  For a list of frame parameters and their effects, see @ref{Frame
Parameters,,, elisp, The Emacs Lisp Reference Manual}.

@cindex initial-frame-alist
  You can also specify a list of frame parameters which apply to just
the initial frame, by customizing the variable
@code{initial-frame-alist}.

  If Emacs is compiled to use an X toolkit, frame parameters that
specify colors and fonts don't affect menus and the menu bar, since
those are drawn by the toolkit and not directly by Emacs.

@node Scroll Bars
@section Scroll Bars
@cindex Scroll Bar mode
@cindex mode, Scroll Bar

  On graphical displays, there is a @dfn{scroll bar} on the side of
each Emacs window.  Clicking @kbd{Mouse-1} on the scroll bar's up and
down buttons scrolls the window by one line at a time.  Clicking
@kbd{Mouse-1} above or below the scroll bar's inner box scrolls the
window by nearly the entire height of the window, like @kbd{M-v} and
@kbd{C-v} respectively (@pxref{Moving Point}).  Dragging the inner box
scrolls continuously.

  If Emacs is compiled on the X Window System without X toolkit
support, the scroll bar behaves differently.  Clicking @kbd{Mouse-1}
anywhere on the scroll bar scrolls forward like @kbd{C-v}, while
@kbd{Mouse-3} scrolls backward like @kbd{M-v}.  Clicking @kbd{Mouse-2}
in the scroll bar lets you drag the inner box up and down.

@findex scroll-bar-mode
@findex toggle-scroll-bar
  To toggle the use of scroll bars, type @kbd{M-x scroll-bar-mode}.
This command applies to all frames, including frames yet to be
created.  To toggle scroll bars for just the selected frame, use the
command @kbd{M-x toggle-scroll-bar}.

@vindex scroll-bar-mode
  To control the use of scroll bars at startup, customize the variable
@code{scroll-bar-mode}.  Its value should be either @code{right} (put
scroll bars on the right side of windows), @code{left} (put them on
the left), or @code{nil} (disable scroll bars).  By default, Emacs
puts scroll bars on the right if it was compiled with GTK+ support on
the X Window System, and on MS-Windows or Mac OS; Emacs puts scroll
bars on the left if compiled on the X Window System without GTK+
support (following the old convention for X applications).

@vindex scroll-bar-width
@cindex width of the scroll bar
  You can also use the X resource @samp{verticalScrollBars} to enable
or disable the scroll bars (@pxref{Resources}).  To control the scroll
bar width, change the @code{scroll-bar-width} frame parameter
(@pxref{Frame Parameters,,, elisp, The Emacs Lisp Reference Manual}).

@node Drag and Drop
@section Drag and Drop
@cindex drag and drop

  In most graphical desktop environments, Emacs has basic support for
@dfn{drag and drop} operations.  For instance, dropping text onto an
Emacs frame inserts the text where it is dropped.  Dropping a file
onto an Emacs frame visits that file.  As a special case, dropping the
file on a Dired buffer moves or copies the file (according to the
conventions of the application it came from) into the directory
displayed in that buffer.

@vindex dnd-open-file-other-window
  Dropping a file normally visits it in the window you drop it on.  If
you prefer to visit the file in a new window in such cases, customize
the variable @code{dnd-open-file-other-window}.

  The XDND and Motif drag and drop protocols, and the old KDE 1.x
protocol, are currently supported.

@node Menu Bars
@section Menu Bars
@cindex Menu Bar mode
@cindex mode, Menu Bar
@findex menu-bar-mode
@vindex menu-bar-mode

  You can toggle the use of menu bars with @kbd{M-x menu-bar-mode}.
With no argument, this command toggles Menu Bar mode, a global minor
mode.  With an argument, the command turns Menu Bar mode on if the
argument is positive, off if the argument is not positive.  To control
the use of menu bars at startup, customize the variable
@code{menu-bar-mode}.

@kindex C-Mouse-3 @r{(when menu bar is disabled)}
  Expert users often turn off the menu bar, especially on text-only
terminals, where this makes one additional line available for text.
If the menu bar is off, you can still pop up a menu of its contents
with @kbd{C-Mouse-3} on a display which supports pop-up menus.
@xref{Menu Mouse Clicks}.

  @xref{Menu Bar}, for information on how to invoke commands with the
menu bar.  @xref{X Resources}, for how to customize the menu bar
menus' visual appearance.

@node Tool Bars
@section Tool Bars
@cindex Tool Bar mode
@cindex mode, Tool Bar
@cindex icons, toolbar

  On graphical displays, Emacs puts a @dfn{tool bar} at the top of
each frame, just below the menu bar.  This is a row of icons which you
can click on with the mouse to invoke various commands.

  The global (default) tool bar contains general commands.  Some major
modes define their own tool bars; whenever a buffer with such a major
mode is current, the mode's tool bar replaces the global tool bar.

@findex tool-bar-mode
@vindex tool-bar-mode
  To toggle the use of tool bars, type @kbd{M-x tool-bar-mode}.  This
command applies to all frames, including frames yet to be created.  To
control the use of tool bars at startup, customize the variable
@code{tool-bar-mode}.

@vindex tool-bar-style
@cindex Tool Bar style
  When Emacs is compiled with GTK+ support, each tool bar item can
consist of an image, or a text label, or both.  By default, Emacs
follows the Gnome desktop's tool bar style setting; if none is
defined, it displays tool bar items as just images.  To impose a
specific tool bar style, customize the variable @code{tool-bar-style}.

@cindex Tool Bar position
  You can also control the placement of the tool bar for the GTK+ tool
bar with the frame parameter @code{tool-bar-position}.  @xref{Frame
Parameters,,, elisp, The Emacs Lisp Reference Manual}.

@node Dialog Boxes
@section Using Dialog Boxes
@cindex dialog boxes

@vindex use-dialog-box
  A dialog box is a special kind of menu for asking you a yes-or-no
question or some other special question.  Many Emacs commands use a
dialog box to ask a yes-or-no question, if you used the mouse to
invoke the command that led to the question.

  To disable the use of dialog boxes, change the variable
@code{use-dialog-box} to @code{nil}.  In that case, Emacs always
performs yes-or-no prompts using the echo area and keyboard input.
This variable also controls whether to use file selection windows (but
those are not supported on all platforms).

@vindex use-file-dialog
@cindex file selection dialog, how to disable
  A file selection window is a special kind of dialog box for asking
for file names.  You can customize the variable @code{use-file-dialog}
to suppress the use of file selection windows, even if you still want
other kinds of dialogs.  This variable has no effect if you have
suppressed all dialog boxes with the variable @code{use-dialog-box}.

@vindex x-gtk-show-hidden-files
@vindex x-gtk-file-dialog-help-text
@cindex hidden files, in GTK+ file chooser
@cindex help text, in GTK+ file chooser
  When Emacs is compiled with GTK+ support, it uses the GTK+ ``file
chooser'' dialog.  Emacs adds an additional toggle button to this
dialog, which you can use to enable or disable the display of hidden
files (files starting with a dot) in that dialog.  If you want this
toggle to be activated by default, change the variable
@code{x-gtk-show-hidden-files} to @code{t}.  In addition, Emacs adds
help text to the GTK+ file chooser dialog; to disable this help text,
change the variable @code{x-gtk-file-dialog-help-text} to @code{nil}.

@node Tooltips
@section Tooltips
@cindex tooltips

  @dfn{Tooltips} are small windows that display text information at
the current mouse position.  They activate when there is a pause in
mouse movement over some significant piece of text in a window, or the
mode line, or some other part of the Emacs frame such as a tool bar
button or menu item.

@findex tooltip-mode
  You can toggle the use of tooltips with the command @kbd{M-x
tooltip-mode}.  When Tooltip mode is disabled, the help text is
displayed in the echo area instead.  To control the use of tooltips at
startup, customize the variable @code{tooltip-mode}.

@vindex tooltip-delay
  The variables @code{tooltip-delay} specifies how long Emacs should
wait before displaying a tooltip.  For additional customization
options for displaying tooltips, use @kbd{M-x customize-group
@key{RET} tooltip @key{RET}}.

@vindex x-gtk-use-system-tooltips
  If Emacs is built with GTK+ support, it displays tooltips via GTK+,
using the default appearance of GTK+ tooltips.  To disable this,
change the variable @code{x-gtk-use-system-tooltips} to @code{nil}.
If you do this, or if Emacs is built without GTK+ support, most
attributes of the tooltip text are specified by the @code{tooltip}
face, and by X resources (@pxref{X Resources}).

  @dfn{GUD tooltips} are special tooltips that show the values of
variables when debugging a program with GUD.  @xref{Debugger
Operation}.

@node Mouse Avoidance
@section Mouse Avoidance
@cindex avoiding mouse in the way of your typing
@cindex mouse avoidance

  On graphical terminals, the mouse pointer may obscure the text in
the Emacs frame.  Emacs provides two methods to avoid this problem.

@vindex make-pointer-invisible
  Firstly, Emacs hides the mouse pointer each time you type a
self-inserting character, if the pointer lies inside an Emacs frame;
moving the mouse pointer makes it visible again.  To disable this
feature, set the variable @code{make-pointer-invisible} to @code{nil}.

@vindex mouse-avoidance-mode
  Secondly, you can use Mouse Avoidance mode, a minor mode, to keep
the mouse pointer away from point.  To use Mouse Avoidance mode,
customize the variable @code{mouse-avoidance-mode}.  You can set this
to various values to move the mouse in several ways:

@table @code
@item banish
Move the mouse to the upper-right corner on any key-press;
@item exile
Move the mouse to the corner only if the cursor gets too close,
and allow it to return once the cursor is out of the way;
@item jump
If the cursor gets too close to the mouse, displace the mouse
a random distance & direction;
@item animate
As @code{jump}, but shows steps along the way for illusion of motion;
@item cat-and-mouse
The same as @code{animate};
@item proteus
As @code{animate}, but changes the shape of the mouse pointer too.
@end table

@findex mouse-avoidance-mode
You can also use the command @kbd{M-x mouse-avoidance-mode} to enable
the mode.  Whenever Mouse Avoidance mode moves the mouse, it also
raises the frame.

@node Non-Window Terminals
@section Non-Window Terminals
@cindex text-only terminal

  On a text-only terminal, Emacs can display only one Emacs frame at a
time.  However, you can still create multiple Emacs frames, and switch
between them.  Switching frames on these terminals is much like
switching between different window configurations.

  Use @kbd{C-x 5 2} to create a new frame and switch to it; use @kbd{C-x
5 o} to cycle through the existing frames; use @kbd{C-x 5 0} to delete
the current frame.

  Each frame has a number to distinguish it.  If your terminal can
display only one frame at a time, the selected frame's number @var{n}
appears near the beginning of the mode line, in the form
@samp{F@var{n}}.

@findex set-frame-name
@findex select-frame-by-name
  @samp{F@var{n}} is in fact the frame's initial name.  You can give
frames more meaningful names if you wish, and you can select a frame
by its name.  Use the command @kbd{M-x set-frame-name @key{RET}
@var{name} @key{RET}} to specify a new name for the selected frame,
and use @kbd{M-x select-frame-by-name @key{RET} @var{name} @key{RET}}
to select a frame according to its name.  The name you specify appears
in the mode line when the frame is selected.

@node Text-Only Mouse
@section Using a Mouse in Text-only Terminals
@cindex mouse support
@cindex terminal emulators, mouse support

Some text-only terminals support mouse clicks in the terminal window.

@cindex xterm
  In a terminal emulator which is compatible with @command{xterm}, you
can use @kbd{M-x xterm-mouse-mode} to give Emacs control over simple
uses of the mouse---basically, only non-modified single clicks are
supported.  The normal @command{xterm} mouse functionality for such
clicks is still available by holding down the @kbd{SHIFT} key when you
press the mouse button.  Xterm Mouse mode is a global minor mode
(@pxref{Minor Modes}).  Repeating the command turns the mode off
again.

@findex gpm-mouse-mode
  In the console on GNU/Linux, you can use @kbd{M-x gpm-mouse-mode} to
enable mouse support.  You must have the gpm server installed and
running on your system in order for this to work.

@iftex
@pxref{MS-DOS Mouse,,,emacs-xtra,Specialized Emacs Features},
@end iftex
@ifnottex
@pxref{MS-DOS Mouse},
@end ifnottex
for information about mouse support on MS-DOS.