\input texinfo   @c -*-texinfo-*-
@comment $Id: qingy.texi 254 2004-03-19 00:11:24Z noberasco $
@comment %**start of header
@setfilename qingy.info
@include version.texi
@settitle Qingy @value{VERSION}
@syncodeindex pg cp
@comment %**end of header
@copying
This manual is for Qingy
(version @value{VERSION}, @value{UPDATED}),
which is a frame-buffered getty substitute

Copyright @copyright{} 2003 Paolo Gianrossi

@quotation
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.2
or any later version published by the Free Software Foundation;
with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
Texts.  A copy of the license is included in the section entitled "GNU
Free Documentation License".
@end quotation
@end copying

@dircategory System programs
@direntry
* qingy: (qingy).
@end direntry

@titlepage
@title Qingy user manual
@subtitle for version @value{VERSION}, @value{UPDATED}
@author Paolo Gianrossi (@email{paolino.gnu@@disi.unige.it})
@page
@vskip 0pt plus 1filll
@insertcopying
@end titlepage

@contents

@ifnottex
@node Top, Introduction, (dir), (dir)
@top Qingy

@insertcopying
@end ifnottex

@menu
* Introduction::                
* Fetching qingy::              
* Configuration ::              
* The settings file::           
* Qingy Themes::                
* The welcomes feature::        
* Screensavers::                
* Using Qingy::                 
* Copying Qingy::               
* Copying::                     
* Index::                       

@detailmenu
 --- The Detailed Node Listing ---

Fetching qingy

* Installing from the tarball::  

Configuration 

* Line options::                

Qingy Themes

* Compatibility note::          
* Introduction to themes::      
* Themes using theme files::    
* Themes using settings file::  

Themes using theme files

* The theme file::              
* theme file examples::         

The theme file

* Screensaver setting::         
* Theme::                       
* Windows::                     

theme file examples

* A basic theme::               
* A complete theme::            

Themes using settings file

* Random themes::               

Screensavers

* Security matters with Qingy screensavers::  
* Rolling your own screensavers::  

Appendix: How to Apply These Terms to Your New Programs

* GNU Free Documentation License::  

@end detailmenu
@end menu

@node  Introduction, Fetching qingy, Top, Top
@comment  node-name,  next,  previous,  up
@chapter Introduction

@cindex eye-candy

Qingy Is Not GettY. 
Qingy is useless anyway: it is just eye-candy for a login screen on
your box.  Still, it's just plain lovely and cool, and we are sure
that you will love it.

Qingy graphical effects are obtained perusing the frame-buffer, thus
avoiding the nuisance of running an X server just to login as it
happens with the various *DMs. Also, it has some nice features, such
as text sessions as well as X sessions, a screensaver, themes to
customize it totally and much much more.

@node  Fetching qingy, Configuration , Introduction, Top
@chapter Fetching qingy

@cindex downloading Qingy
@cindex Qingy homepage
@cindex CVS
@cindex Gentoo and Qingy
@cindex @kbd{emerge qingy}

You can download the latest stable version of Qingy from SourceForge
(@uref{http://qingy.sourceforge.net}). You should get the latest
stable version, unless you are a developer or really brave: in those
cases, you might want to get the CVS version. This is the bleeding
edge version, the one we are using everyday for our small and big
changes in the code. It might even not compile (although we really try
to avoid that) and it is totally unsupported. To get this version you
will need a CVS client. You should read the huge and very deep
SourceForge CVS documentation, but something like @kbd{cvs
-d:pserver:anonymous@@cvs.sf.net:/cvsroot/qingy co qingy} might do the
trick.

Also, if you are using Gentoo as your GNU/Linux distribution, you can
@kbd{emerge qingy}.

@menu
* Installing from the tarball::  
@end menu
@node  Installing from the tarball,  , Fetching qingy, Fetching qingy
@comment  node-name,  next,  previous,  up
@section Installing from the tarball

@cindex installing
@cindex tarball
@cindex Linux
@cindex @kbd{fbset}
@cindex @file{/etc/fb.modes}

Before starting to compile qingy, you should check to have the
DirectFB library installed. You should also configure DirectFB for
your frame-buffer device: run @kbd{fbset} and paste the output as the
first entry in @file{/etc/fb.modes}. 

@cindex @kbd{make}
@cindex @kbd{configure}
Fetch the tarball and compile it more or less as any Linux package:
@enumerate
@item
@kbd{tar -jvzf qingy-@value{VERSION}.tar.bz2}
@item
@kbd{cd qingy-@value{VERSION}}
@item
@kbd{./configure}
@item
@kbd{make}
@item
@kbd{make install}
@end enumerate

@cindex @file{/etc/inittab}
Finally, you should change your @file{/etc/inittab} file from something like

@verbatim

#
# ... more stuff here 

# TERMINALS

c1:12345:respawn:/sbin/agetty 38400 tty1 linux
c2:12345:respawn:/sbin/agetty 38400 tty2 linux
c3:12345:respawn:/sbin/agetty 38400 tty3 linux
c4:12345:respawn:/sbin/agetty 38400 tty4 linux
c5:12345:respawn:/sbin/agetty 38400 tty5 linux
c6:12345:respawn:/sbin/agetty 38400 tty6 linux

# and more stuff following ...

# End of /etc/inittab
@end verbatim

to something like 

@verbatim

#
# ... more stuff here 

# TERMINALS

c1:12345:respawn:/sbin/qingy tty1  --black-screen-workaround --no-shutdown-screen
c2:12345:respawn:/sbin/qingy tty2  --black-screen-workaround --no-shutdown-screen
c3:12345:respawn:/sbin/qingy tty3  --black-screen-workaround --no-shutdown-screen
c4:12345:respawn:/sbin/agetty 38400 tty4 linux

# and more stuff following ...

# End of /etc/inittab
@end verbatim

Please note that we left a terminal (tty4) set to the old getty. This
is because Qingy is still at beta release. Thus, if something goes
wrong, this way you'll still have a way to login on your system.

Note also that we passed some options to Qingy. @c @xref{Line options}
, to see what options are available and what they do.

@cindex launching Qingy
At this point you're ready to launch Qingy. From a shell prompt type
@kbd{init Q} and then @kbd{killall -9 agetty} (or whatever getty you
use). Logout and find Qingy running as the login manager now on the
terminals you've set for it.

@node  Configuration , The settings file, Fetching qingy, Top
@comment  node-name,  next,  previous,  up
@chapter Configuration 

@cindex configuring Qingy
Qingy is very customizable, making it possible to have almost exactly
the behavior you want it to have. Configuration is done site-widely
and breaks down to basically two aspects: ``What it looks like'', and
``What happens when I do something''. Of course, you cannot have a
user-based configuration, as when you have Qingy running, you don't
know yet which user is sitting in front of it.

Customization is obtained in three different ways: through line
options, through the @file{/etc/qingy/settings} file and through themes.

@menu
* Line options::                
@end menu

@node  Line options,  , Configuration , Configuration
@comment  node-name,  next,  previous,  up
@section Line options

@cindex line options

When Qingy is called by init, it is passed some options. These options
change some of Qingy behavior in different ways. Here is a list of all possible options.

@table @code
@cindex @kbd{--fb-device}
@item --fb-device <device>
	Use <device> as frame-buffer device.

@cindex @kbd{--hide-password}
@item --hide-password
	Do not show password asterisks.

@cindex @kbd{--hide-user}
@item --hide-lastuser
	Do not display last user name.

@cindex @kbd{--disable-user}
@item --disable-lastuser
	Do not remember last user name.

@cindex @kbd{--verbose}
@item --verbose
	Display some diagnostic messages on stderr.

@cindex @kbd{--no-shutdown-screen}
@item --no-shutdown-screen
	Close DirectFB mode before shutting down.
	This way you will see system shutdown messages.

@cindex @kbd{--screensaver}
@item --screensaver <timeout>
	Activate screensaver after <timeout> minutes (default is 5).
	A value of 0 disables screensaver completely.

@cindex @kbd{--black-screen-workaround}
@item --black-screen-workaround
	Try this if you get a black screen instead of a text console.
	Note: switching to another vt and back also solves the problem.

@end table

@node  The settings file, Qingy Themes, Configuration , Top
@comment  node-name,  next,  previous,  up
@chapter The ``settings'' file

@cindex @file{settings}
The main configuration file for Qingy is
@file{/etc/qingy/settings}. All global settings for Qingy are found in
this file. 

A typical @file{settings} file might look like this: 

@verbatim

# Directory containing X sessions
x_sessions = "/etc/X11/Sessions/"

# Directory containing text mode sessions
text_sessions = "/etc/qingy/sessions/"

# Full path to the 'xinit' executable
xinit = "/usr/X11R6/bin/xinit"

screensaver "running_time"  =
                   "%H:%M:%S" 
 
# What theme do you want (you can also specify 'random')
theme = random

# theme = "default"

# Who is allowed to shut down the system?
# Allowed options are 'everyone', 'root', 'noone'

shutdown_policy = everyone

@end verbatim

It is pretty self-explicative: so let's see what else can we do with
it: @code{screensaver} can be set to any of the screensavers found in
@file{/etc/qingy/screensaver}. @xref{Screensavers}, for more details
about screensavers in Qingy.

Theme can be set to random (without quotes, that means you can have an
actual theme called @samp{random}...) or to a real theme by quoting
its name (@pxref{Qingy Themes} for more details on theming in Qingy).

Also, you can set global theme settings in the @file{settings} file,
much like you'd do in a @file{theme} file (again, @pxref{Qingy Themes}
for better covering of the... well... theme). So, if you had in your
@file{settings} file something like:

@verbatim

#...

theme="default"
theme {
      background = "/var/logo.jpeg"
}

#...

@end verbatim

You'd be displaying the default theme with a different background
(namely, @file{/var/logo/jpeg}.  

@emph{Note: this nice trick doesn't actually work when it would be
most useful: along with a @code{theme = default} command. Bear with
us. We'll try to have that working soon enough...}

@node  Qingy Themes, The welcomes feature, The settings file, Top
@comment  node-name,  next,  previous,  up
@chapter Qingy Themes

@cindex themes
Qingy @value{VERSION} is completely customizable in its appearance
through a theming interface. We shall see how these themes are made
and used and what is possible to be done with themes in Qingy.

@menu
* Compatibility note::          
* Introduction to themes::      
* Themes using theme files::    
* Themes using settings file::  
@end menu

@node Compatibility note, Introduction to themes, Qingy Themes, Qingy Themes
@section Compatibility note

@cindex themes compatibility
@cindex compatibility, themes --
Settings and theme file syntax and semantics have radically changed since
version 0.2. Hence, old-style themes are no longer compatible with
Qingy.  Please read thoroughly this file and change your themes
appropriately. 


@node Introduction to themes, Themes using theme files, Compatibility note, Qingy Themes
@section Introduction to themes
For qingy 0.2, a theme was a subdirectory in @file{/etc/qingy/themes}.
The name of this directory was the name of the theme.
You could select a theme by editing @file{/etc/qingy/settings}
and modifying the line @code{THEME default} with the name of the
theme you wanted to use (e.g.: @code{THEME playboy}).

This is still true in Qingy @value{VERSION}, although the rules vary. 

@cindex @file{themer}
You might want to use the Perl script @file{themer} in Qingy source
tree to translate your old themes to new ones.

Still, it is also possible to define themes in a different way:
directly in the settings file. This way, you might have some
properties which are always set in a certain way, while others are set
by the theme files.

@cindex incremental theme files
It is also possible to include many theme files. The rules will be
added incrementally: that is, new settings will override old ones.

@node  Themes using theme files, Themes using settings file, Introduction to themes, Qingy Themes
@comment  node-name,  next,  previous,  up
@section Themes using theme files

@cindex theme files
As said, a theme may be a directory in @file{/etc/qingy/themes}. The
subdirectory name will be the name of the theme. 

In this directory, you should put: 
@itemize @bullet
@item
A background image.

@item
A font file supported by DirectFB. TTF fonts are OK.

@item
Two images for each button you want, one for it's normal appearance
(filename: @file{@code{stem}_normal.png}), one for when mouse passes
over it (filename:@file{@code{stem}_mouseover.png}).

@code{stem} is a name of your choice, but must be the same for the same button.

@item
A config file (filename:@file{theme}). @xref{The theme file}, to know how to write that.

@end itemize

@menu
* The theme file::              
* theme file examples::         
@end menu

@node  The theme file, theme file examples, Themes using theme files, Themes using theme files
@comment  node-name,  next,  previous,  up
@subsection The theme file

@cindex theme files
@cindex @file{theme}
The file called @file{theme} in your theme directory is what gives the
rules for your theme. You can set the actual theme there (the look and
feel of Qingy), a screensaver and the widget disposition.

In the @file{theme} file, everything after a @code{#} is considered
comment and ignored. 

@menu
* Screensaver setting::         
* Theme::                       
* Windows::                     
@end menu

@node  Screensaver setting, Theme, The theme file, The theme file
@comment  node-name,  next,  previous,  up
@subsubsection Screensaver setting

@cindex screensavers in @file{theme} file
You can set a screensaver putting on a line the following:
@code{screensaver=pixel} or @code{screensaver=photo "/path/to/pics"
"path/to/pics" ...}.

@node  Theme, Windows, Screensaver setting, The theme file
@comment  node-name,  next,  previous,  up
@subsubsection ``Theme''

@cindex theme section in @file{theme} file
You can set a ``theme'' (look and feel) making a @code{theme@{...@}} block.

Therein you can set various properties, as assignments:

     @multitable @columnfractions .35 .35 .3
     @item @code{mask_text_color} =
     @tab @code{color}
     @tab The color of the text in the login window
@item
     @item @code{cursor_text_color} = 
     @tab @code{color}
     @tab The color of the blinking cursor
@item
     @item @code{other_text_color} =
     @tab @code{color}
     @tab The color of the text of other windows (such as the shutdown
     window)
@item
     @item @code{background} = 
     @tab @code{"/path/to/file"}
     @tab The background image file pathname
@item
     @item @code{font} =
     @tab @code{"/path/to/file"}
     @tab The font file pathname
@item
     @item @code{button_opacity} =
     @tab @code{number}
     @tab Alpha channel value for buttons
@item
     @item @code{window_opacity} =
     @tab @code{number}
     @tab Foreground alpha channel value of windows
@item
     @item @code{selected_window_opacity} =
     @tab @code{number}
     @tab Foreground alpha channel value for the active window
     @end multitable

A @code{color} might be a hexadecimal quadruplet in the form of
@code{[aabbccdd]}, which will set the red value to 0xAA, the green
value to 0xBB, the blue value to 0xCC and the alpha channel value to
0xDD. Or, it might be four decimal value comma-separated fields such
as @code{20, 30, 40, 50}, which will set the red value to 20, the
green value to 30, the blue value to 40 and the alpha channel value to
50. The opacity numbers must be unsigned integer decimal values,
ranging from 0 to 255.

@node   Windows,  , Theme, The theme file
@comment  node-name,  next,  previous,  up
@subsubsection Windows

Finally, you can define windows on your screen. In Qingy, a
@dfn{window} is any visible widget to be displayed. 

Each window is defined inside a @code{window@{...@}} block.  Therein
you can define some fields to define the position, size and behavior
of the window.

The fields you can set are the following:


@multitable @columnfractions .20 .15 .55
     @item @code{x} =
     @tab @code{number}
     @tab The left column of the window
@item
     @item @code{y} =
     @tab @code{number}
     @tab The top row of the window
@item
     @item @code{height} =
     @tab @code{number}
     @tab The height in pixels of the window
@item
     @item @code{width} =
     @tab @code{number}
     @tab The width in pixels of the window
@item
     @item @code{type} =
     @tab @code{"type"}
     @tab The type of the window (see below)
@item
     @item @code{command} = 
     @tab @code{"command"}
     @tab Command to be executed (see below)
@item
     @item @code{content} = 
     @tab @code{"content"}
     @tab Content of the widget (see below)
@item
     @item @code{time} =
     @tab @code{number}
     @tab Seconds interval for command polling (see below)
@end multitable
     
The type of a window must be one in the following:

@table @b

@item label
Displays a text label with a certain text at given position.
The displayed text can be either static, given as the @code{content}
field or dynamic, as the output of a shell command, given in the
@code{command} field. In this case, the command is run every
@code{time} seconds and its output redisplayed. If time is set
to 0, command is executed just once.

@item button
Displays a button at given position. 
Command must be one of @code{halt}, @code{reboot}, @code{sleep} or
@code{screensave}.
Commands @code{halt} and @code{reboot} will be executed (hence halting
the system or rebooting it) following the @dfn{shutdown policy}
@ifnotplaintext
     (@pxref{The settings file})
@end ifnotplaintext
.
In the @code{content} field, you should put a
@code{/path/to/stem}. You should also have files
@file{/path/to/stem_normal.png} and
@file{/path/to/stem_mouseover.png}. These are two images that will be
used to display your button respectively normally and when the mouse
is on them.

@item login
A login text box. Users will have to write their user-name here in
order to log in. There should be always one and just one of these on
your window. Having none will result in displaying a default one,
having more than one will result in an error.

@item password
A login text box. Users will have to write their password here in
order to log in. There should be always one and just one of these on
your window. Having none will result in displaying a default one,
having more than one will result in an error.

@item combo
Displays a combo box at given position. 
The only command supported so far is @code{sessions}. It will let user
choose which session run at login.

@end table

Whenever a field is set for a window with a type not using that field,
the value of the field is silently ignored.

@node  theme file examples,  , The theme file, Themes using theme files
@comment  node-name,  next,  previous,  up
@subsection theme file examples

We shall see some examples of the file @file{theme} of a theme.

@menu
* A basic theme::               
* A complete theme::            
@end menu

@node  A basic theme, A complete theme, theme file examples, theme file examples
@comment  node-name,  next,  previous,  up
@subsubsection A basic theme
@verbatim
# basic theme for Qingy 0.3
# by Paolo Gianrossi

theme @{
      background = "bg.png"
      font = "decker.ttf"
      window_opacity = 240
      selected_window_opacity = 255
      mask_text_color = 90, 200, 90
      cursor_text_color = 90, 200, 90
      other_text_color = 90, 200, 90
@}
@end verbatim

In this case, only the look and feel was set. No buttons are used,
hence @code{button_opacity} is not defined. Color is uniform, a
greenish fade. The selected window is more vivid than the rest, due to
@code{selected_window_opacity}. 

@node  A complete theme,  , A basic theme, theme file examples
@comment  node-name,  next,  previous,  up
@subsubsection A complete theme

@verbatim

screensaver="running_time"

theme
{	
	background = "background.png"
	font = "decker.ttf"

# opacity values, from 0 (transparent) to 255 (opaque)
	button_opacity          = 128
	window_opacity          = 128
	selected_window_opacity = 207

# Colors can be given in a hex quadruplet (values from 00 to ff)
# or via comma-separated decimals (0 to 255). Format is RGBA
#	mask_text_color   = [ 28b428ff ]
#	cursor_text_color = [ 145a14dd ]
#	other_text_color  = [ 404040ff ]
	default_text_color   = 70,70, 240, 255
	default_cursor_color = 70,  70, 240, 221
	other_text_color     =  70,70 , 255, 255
}

window
{
	# window geometry
	x      = 0
	y      = 20
	width  = 780
	height = 200

	text_size        = small
	text_orientation = center
	text_color       = 00, 0, 240, 255
	cursor_color     = 00, 0,  240, 221

	# update time, 0 means do not update
	time = 0

	# window type, allowed values are:
	# "label", "button", "login", "password", "combo"
	type    = "label"
	content = "<INS_CMD_HERE>"
	command = "fortune -n 75 -s | perl -0p -e 's/[\n\t]/ /g' "
}

window
{
	# window geometry
	x      = 100
	y      = 220
	width  = 120
	height = 50

	text_size        = large
	text_orientation = right
	text_color       = 0, 0, 240, 255
	cursor_color     = 0, 0,  240, 221

	# update time, 0 means do not update
	time = 0

	# window type, allowed values are:
	# "label", "button", "login", "password", "combo"
	type    = "label"
	content = "login:"
	linkto  = "login"
}

window
{
	# window geometry
	x      = 240
	y      = 220
	width  = 560
	height = 50

	text_size    = large
	text_color       = 0, 0, 240, 255
	cursor_color     = 0, 0,  240, 221

	# update time, 0 means do not update
	time = 0

	# window type, allowed values are:
	# "label", "button", "login", "password", "combo"
	type = "login"
}

window
{
	# window geometry
	x      = 100
	y      = 295
	width  = 120
	height = 50

	text_size        = large
	text_orientation = right
	text_color       = 0, 0, 240, 255
	cursor_color     = 0, 0,  240, 221

	# update time, 0 means do not update
	time = 0

	# window type, allowed values are:
	# "label", "button", "login", "password", "combo"
	type    = "label"
	content = "passwd:"
	linkto  = "password"
}

window
{
	# window geometry
	x      = 240
	y      = 295
	width  = 560
	height = 50

	text_size    = large
	text_color       = 0, 0, 240, 255
	cursor_color     = 0, 0,  240, 221

	# update time, 0 means do not update
	time = 0

	# window type, allowed values are:
	# "label", "button", "login", "password", "combo"
	type = "password"
}

window
{
	# window geometry
	x      = 100
	y      = 370
	width  = 120
	height = 50

	text_size        = large
	text_orientation = right
	text_color       = 0, 0, 240, 255
	cursor_color     = 0, 0,  240, 221

	# update time, 0 means do not update
	time = 0

	# window type, allowed values are:
	# "label", "button", "login", "password", "combo"
	type    = "label"
	content = "session:"
	linkto  = "session"
}

window
{
	# window geometry
	x      = 240
	y      = 370
	width  = 560
	height = 50

	text_size    = large
	text_color       = 0, 0, 240, 255
	cursor_color     = 0, 0,  240, 221

	# update time, 0 means do not update
	time = 0

	# window type, allowed values are:
	# "label", "button", "login", "password", "combo"
	type = "combo"

	# In this case: what text do you want to display?
	command = "sessions"
}


window
{
	# window geometry
	x    = 755
	y    = 562
	type = "button"

	# Allowed commands:
	# "halt", "reboot", "sleep", "screensaver"
	command = "halt"

	# Image prefix: will be converted to
	# "<name>_normal.png" and "<name>_mouseover.png"
	content = "power"
}

window
{
	x       = 755
	y       = 515
	type    = "button"
	command = "reboot"
	content = "reset"
}

window
{
	x       = 755
	y       = 470
	type    = "button"
	command = "screensaver"
	content = "screensaver"
}

window
{
	x       = 755
	y       = 425
	type    = "button"
	command = "sleep"
	content = "sleep"
}
@end verbatim

@node  Themes using settings file,  , Themes using theme files, Qingy Themes
@comment  node-name,  next,  previous,  up
@section Themes using settings file

In the setting file (@file{/etc/qingy/settings}), you may, since Qingy
0.3 define global theme properties exactly as you would in a theme
file: just begin a @code{theme@{...@}} section in your settings and
put everything you need there.

Please note that, being themes incremental, you can for example do
something like this:

@example

#... more of the settings file, not relevant here

theme="mytheme"

theme@{
        background="/usr/share/company_logo.png"
@}

@end example

and you will get theme @file{mytheme} with @code{background} set to
@file{/usr/share/company_logo.png}. 

@menu
* Random themes::               
@end menu

@node  Random themes,  , Themes using settings file, Themes using settings file
@comment  node-name,  next,  previous,  up
@subsection Random themes

You can also get a fresh new randomly selected theme from your theme
collection every time you start Qingy (as every logout, for
example). Just put the line @code{theme random} in your
@file{settings} file instead of putting @code{theme="name"} and Qingy
will select for you a random theme each time.

Remember, you can bypass some properties using the in-line theme
functionality:

@example

theme random

theme@{
        background="/usr/share/company_logo.png"
@}

@end example

is perfectly valid.



@node  The welcomes feature, Screensavers, Qingy Themes, Top
@comment  node-name,  next,  previous,  up
@chapter The welcomes feature

The welcomes feature in Qingy is just the natural evolution of the
``Greetings master!'' feature for root: basically it lets you define
for each user the welcome message to display. To do this, create file
@file{/etc/qingy/welcomes} and insert, one on each line, the user name,
a space and just whatever you want to display. For example:

@example
paolino The answer is 42!
michele Ah! What a lovely day, my Author...
root    It's not funny... Why do you wanna log like that!?
@end example

will display @samp{The answer is 42} when I (paolino) log in, and so
on (you got the point).

Another way to define the welcome message is using a file called
@file{.qingy_welcome} in a user's home directory: when that user logs
in, the first line of this file is displayed.  This lets each user
personalise her welcome message at her taste.  

The order of execution is the following: first, the
@file{~/.qingy_welcome} file is searched. If that is not ound or it
cannot be used, an entry in @file{/etc/qingy/welcomes} is searched. If
that is not found, a default message (@samp{starting selected
session}) is displayed as the welcome message.

@node  Screensavers, Using Qingy, The welcomes feature, Top
@comment  node-name,  next,  previous,  up
@chapter Screensavers

Qingy has now a modularized screensaver support: basically, you or
anyone else can write her own screensaver as a module and distribute
it. You'll just have to install it and call it from the
@file{settings} file. 

A screensaver for qingy is just a function made in a certain way, in a
module built in a certain way, stored in a certain directory. Now pay
big attention: @emph{@b{THIS IS VERY IMPORTANT: You are making Qingy
execute arbitrary code through this function!! Please go on reading!!}}

@menu
* Security matters with Qingy screensavers::  
* Rolling your own screensavers::  
@end menu

@node Security matters with Qingy screensavers, Rolling your own screensavers, Screensavers, Screensavers
@comment  node-name,  next,  previous,  up
@section Security matters with Qingy screensavers

Ok. Let's make this clear: @emph{@b{YOU SHOULDN'T INSTALL A
SCREENSAVER UNLESS YOU KNOW EXACTLY WHAT YOU ARE DOING, OR YOU REALLY
TRUST THE PERSON WHO GAVE IT TO YOU!!!!}} 

Indeed, a screensaver is just a piece of code which is executed upon
some events by Qingy: that is when you press the saver button on your
interface or the screen is idle for five minutes.  The piece of code
should basically perform a loop until someone presses a key or moves
the mouse. Inside the loop are the instructions to display something
on the screen. But what if Joe M. Alicious put in the loop some nasty
instruction like ``remove all the files on your disk and die'' or
``email to me all your passwords'' or such?  Then he would make a nice
package and post it on the web for people to download. You could get
it and install it. And the first time you try you get pain and
destruction.  So now you see what I mean with @samp{you shouldn't install a
screensaver unless you know exactly what you are doing, or you really
trust the person who gave it to you}. If you can read C, you probably
could get a glimpse of what's going on directly there in. Normally a
screensaver is quite a small file, from a few tens to maybe a couple
of hundred lines of code.  You might also ask YLE, Your Local Expert,
to check for you. Or just tell us where to get it: we'll most probably
want to try it and be sure that we will check for bad things in there
before we even compile it... :-)

Still, remember: you might get in trouble by using a screensaver you
don't totally trust.

Ah, by the way, if you have any idea on how to improve a little this
HUGE security breach, please email me (paolino@@gnu.disi.unige.it) and
tell me how. Please. 

@node  Rolling your own screensavers,  , Security matters with Qingy screensavers, Screensavers
@comment  node-name,  next,  previous,  up
@section Rolling your own screensavers

So you are one of those people that laugh if I say ``mknod florida b 5
1 is Miami Device'' @footnote{Actually if you ask why should the
console be called florida, you are a bit too scary even for me...}
and normally use words like frobnicate and foobar. And you want to
write your own Qingy screensaver, as you really see that our ones
suck. Very nice: here's how. 

First, you should remember that you are going to write Free
Software. You have to: when you include @file{screensaver_module.h},
you use code I wrote, and that comes under the GNU GPL
(@pxref{Copying} for a copy of this license). So you have to use the
same license. If you wanted to keep all your programming secrets to
yourself, you are a bad person. But if you want to make money with
your screensavers, you are a really really nice person: please
remember, you are legally authorized to sell Free Software for as much
as you manage to get from your customer. You are actually encouraged
to do it: if you do and succeed, you'll be able maybe to live on Free
Software and you'll be able to improve Free Software as your job. 

This said, create a directory called as the screensaver you want to
create and @kbd{cd} to it.

Then just pop your favorite text editor up (we suggest GNU
Emacs) and start typing. 

You should include at least @file{screensaver_module.h}. This file
contains all the structures and wrappers for the screensaver module to
use.  This file is normally located in
@file{/etc/qingy/screensavers/}, which is also where your screensaver
modules will be installed. Just @code{#include
<screensaver_module.h>}. The @file{Makefile} will take care of
locating it correctly.

Then you should just make a function with the following prototype:

@code{void screen_saver_entry(Q_screen_t env)}

@code{Q_screen_t} is a structure defined in
@file{screensaver_module.h}. It has the following fields:

@deftypevar   IDirectFB* dfb

This is the DirectFB handle used by Qingy.

@end deftypevar

@deftypevar  IDirectFBSurface* surface

The drawable surface for the screensaver.

@end deftypevar

@deftypevar  IDirectFBEventBuffer* screen_saver_events

The set of events that should make the screensaver return.
@end deftypevar

@deftypevar  int screen_width

Width of screen in pixels.
@end deftypevar

@deftypevar  int screen_height

Width of screen in pixels.
@end deftypevar

@deftypevar  struct _image_paths *image_paths

Width of screen in pixels. 
@end deftypevar

@deftypevar  char** params

Array of the strings passed as arguments to the screensaver in the
configuration file. It's guaranteed that the order of the strings is
the same as in the config file.
@end deftypevar

In the function @code{screen_saver_entry} you just write the code you
want the screensaver to perform. This is usually some sort of loop
that displays something on the screen and exits the loop to return
when one of the events occur. Still, you can just make your own
behavior (e.g. password locking, time-related lock, etc.)

The visible behavior (displaying stuff on the screen) is accomplished
by writing normal DirectFB C code. Please, see
@uref{http://directfb.org, the DirectFB homepage} for more details.

Once you're done, you should build and install the screensaver. The
correct way to do this is to use a Makefile that you will distribute
along with your screensaver.  If you feel like it, you could even use
the Auto-tools to automate the process.  Or, you might take ---as we
advise--- our screensaver @file{Makefile} from the Qingy source
distribution.  You won't have to change a word in it: just copy it to
your screensaver directory and @kbd{make}, @kbd{make install}.  It
will automagically fix itself to work with your own screensaver.  

Once this works, you would want to distribute it.  Put a copy of the
GPL in the directory, in a file named @file{COPYING}.  Don't forget to
insert a Copyright notice in the beginning of your source files.  Then
@kbd{make dist}. You will find a @file{tar.gz} archive containing your
screensaver in a distributable form.


@node Using Qingy, Copying Qingy, Screensavers, Top
@comment  node-name,  next,  previous,  up
@chapter Using Qingy

Qingy has a very intuitive interface, so you should be able to use it
properly since the first time.

On your screen, you might have different widgets, due to theme and
configuration, but what you will always find are the login field, the
password field and the Sessions box. In the text fields, you can edit
normally using your keyboard. Arrows will move in the text.

@node  Copying Qingy, Copying, Using Qingy, Top
@comment  node-name,  next,  previous,  up
@appendix Copying This Manual and Qingy

Qingy is Free Software. That means that you can freely use, copy,
modify Qingy. You don't even have to tell us if you do so. But if you
do, you have to let others have the same rights you do. For this
reason, Qingy comes under the GNU General Public
License. @xref{Copying}, for a copy of this License. You should read
the license before you do anything with Qingy.

Free Software needs Free Documentation. This is a Free manual.

It would be useless to have a piece of Free Software without
appropriate documentation. This documentation must, of course, be
Free. That is, you may use, copy and modify it. You can actually use,
copy, even print and publish for money, even write again whole parts
of it. You don't even have to tell us this. But you must permit others
to do the same. This manual is published under the GNU Free
Documentation License. @xref{GNU Free Documentation License}, for a
copy of this License. Before you do anything with this manual, except
maybe reading it, you should read the license.

@node Copying, Index, Copying Qingy, Top
@unnumbered GNU GENERAL PUBLIC LICENSE
@center Version 2, June 1991

@c This file is intended to be included in another file.

@display
Copyright @copyright{} 1989, 1991 Free Software Foundation, Inc.
59 Temple Place - Suite 330, Boston, MA  02111-1307, USA

Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
@end display

@unnumberedsec Preamble

  The licenses for most software are designed to take away your
freedom to share and change it.  By contrast, the GNU General Public
License is intended to guarantee your freedom to share and change free
software---to make sure the software is free for all its users.  This
General Public License applies to most of the Free Software
Foundation's software and to any other program whose authors commit to
using it.  (Some other Free Software Foundation software is covered by
the GNU Library General Public License instead.)  You can apply it to
your programs, too.

  When we speak of free software, we are referring to freedom, not
price.  Our General Public Licenses are designed to make sure that you
have the freedom to distribute copies of free software (and charge for
this service if you wish), that you receive source code or can get it
if you want it, that you can change the software or use pieces of it
in new free programs; and that you know you can do these things.

  To protect your rights, we need to make restrictions that forbid
anyone to deny you these rights or to ask you to surrender the rights.
These restrictions translate to certain responsibilities for you if you
distribute copies of the software, or if you modify it.

  For example, if you distribute copies of such a program, whether
gratis or for a fee, you must give the recipients all the rights that
you have.  You must make sure that they, too, receive or can get the
source code.  And you must show them these terms so they know their
rights.

  We protect your rights with two steps: (1) copyright the software, and
(2) offer you this license which gives you legal permission to copy,
distribute and/or modify the software.

  Also, for each author's protection and ours, we want to make certain
that everyone understands that there is no warranty for this free
software.  If the software is modified by someone else and passed on, we
want its recipients to know that what they have is not the original, so
that any problems introduced by others will not reflect on the original
authors' reputations.

  Finally, any free program is threatened constantly by software
patents.  We wish to avoid the danger that re-distributors of a free
program will individually obtain patent licenses, in effect making the
program proprietary.  To prevent this, we have made it clear that any
patent must be licensed for everyone's free use or not licensed at all.

  The precise terms and conditions for copying, distribution and
modification follow.

@iftex
@unnumberedsec TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
@end iftex
@ifinfo
@center TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
@end ifinfo

@enumerate 0
@item
This License applies to any program or other work which contains
a notice placed by the copyright holder saying it may be distributed
under the terms of this General Public License.  The ``Program'', below,
refers to any such program or work, and a ``work based on the Program''
means either the Program or any derivative work under copyright law:
that is to say, a work containing the Program or a portion of it,
either verbatim or with modifications and/or translated into another
language.  (Hereinafter, translation is included without limitation in
the term ``modification''.)  Each licensee is addressed as ``you''.

Activities other than copying, distribution and modification are not
covered by this License; they are outside its scope.  The act of
running the Program is not restricted, and the output from the Program
is covered only if its contents constitute a work based on the
Program (independent of having been made by running the Program).
Whether that is true depends on what the Program does.

@item
You may copy and distribute verbatim copies of the Program's
source code as you receive it, in any medium, provided that you
conspicuously and appropriately publish on each copy an appropriate
copyright notice and disclaimer of warranty; keep intact all the
notices that refer to this License and to the absence of any warranty;
and give any other recipients of the Program a copy of this License
along with the Program.

You may charge a fee for the physical act of transferring a copy, and
you may at your option offer warranty protection in exchange for a fee.

@item
You may modify your copy or copies of the Program or any portion
of it, thus forming a work based on the Program, and copy and
distribute such modifications or work under the terms of Section 1
above, provided that you also meet all of these conditions:

@enumerate a
@item
You must cause the modified files to carry prominent notices
stating that you changed the files and the date of any change.

@item
You must cause any work that you distribute or publish, that in
whole or in part contains or is derived from the Program or any
part thereof, to be licensed as a whole at no charge to all third
parties under the terms of this License.

@item
If the modified program normally reads commands interactively
when run, you must cause it, when started running for such
interactive use in the most ordinary way, to print or display an
announcement including an appropriate copyright notice and a
notice that there is no warranty (or else, saying that you provide
a warranty) and that users may redistribute the program under
these conditions, and telling the user how to view a copy of this
License.  (Exception: if the Program itself is interactive but
does not normally print such an announcement, your work based on
the Program is not required to print an announcement.)
@end enumerate

These requirements apply to the modified work as a whole.  If
identifiable sections of that work are not derived from the Program,
and can be reasonably considered independent and separate works in
themselves, then this License, and its terms, do not apply to those
sections when you distribute them as separate works.  But when you
distribute the same sections as part of a whole which is a work based
on the Program, the distribution of the whole must be on the terms of
this License, whose permissions for other licensees extend to the
entire whole, and thus to each and every part regardless of who wrote it.

Thus, it is not the intent of this section to claim rights or contest
your rights to work written entirely by you; rather, the intent is to
exercise the right to control the distribution of derivative or
collective works based on the Program.

In addition, mere aggregation of another work not based on the Program
with the Program (or with a work based on the Program) on a volume of
a storage or distribution medium does not bring the other work under
the scope of this License.

@item
You may copy and distribute the Program (or a work based on it,
under Section 2) in object code or executable form under the terms of
Sections 1 and 2 above provided that you also do one of the following:

@enumerate a
@item
Accompany it with the complete corresponding machine-readable
source code, which must be distributed under the terms of Sections
1 and 2 above on a medium customarily used for software interchange; or,

@item
Accompany it with a written offer, valid for at least three
years, to give any third party, for a charge no more than your
cost of physically performing source distribution, a complete
machine-readable copy of the corresponding source code, to be
distributed under the terms of Sections 1 and 2 above on a medium
customarily used for software interchange; or,

@item
Accompany it with the information you received as to the offer
to distribute corresponding source code.  (This alternative is
allowed only for noncommercial distribution and only if you
received the program in object code or executable form with such
an offer, in accord with Subsection b above.)
@end enumerate

The source code for a work means the preferred form of the work for
making modifications to it.  For an executable work, complete source
code means all the source code for all modules it contains, plus any
associated interface definition files, plus the scripts used to
control compilation and installation of the executable.  However, as a
special exception, the source code distributed need not include
anything that is normally distributed (in either source or binary
form) with the major components (compiler, kernel, and so on) of the
operating system on which the executable runs, unless that component
itself accompanies the executable.

If distribution of executable or object code is made by offering
access to copy from a designated place, then offering equivalent
access to copy the source code from the same place counts as
distribution of the source code, even though third parties are not
compelled to copy the source along with the object code.

@item
You may not copy, modify, sublicense, or distribute the Program
except as expressly provided under this License.  Any attempt
otherwise to copy, modify, sublicense or distribute the Program is
void, and will automatically terminate your rights under this License.
However, parties who have received copies, or rights, from you under
this License will not have their licenses terminated so long as such
parties remain in full compliance.

@item
You are not required to accept this License, since you have not
signed it.  However, nothing else grants you permission to modify or
distribute the Program or its derivative works.  These actions are
prohibited by law if you do not accept this License.  Therefore, by
modifying or distributing the Program (or any work based on the
Program), you indicate your acceptance of this License to do so, and
all its terms and conditions for copying, distributing or modifying
the Program or works based on it.

@item
Each time you redistribute the Program (or any work based on the
Program), the recipient automatically receives a license from the
original licensor to copy, distribute or modify the Program subject to
these terms and conditions.  You may not impose any further
restrictions on the recipients' exercise of the rights granted herein.
You are not responsible for enforcing compliance by third parties to
this License.

@item
If, as a consequence of a court judgment or allegation of patent
infringement or for any other reason (not limited to patent issues),
conditions are imposed on you (whether by court order, agreement or
otherwise) that contradict the conditions of this License, they do not
excuse you from the conditions of this License.  If you cannot
distribute so as to satisfy simultaneously your obligations under this
License and any other pertinent obligations, then as a consequence you
may not distribute the Program at all.  For example, if a patent
license would not permit royalty-free redistribution of the Program by
all those who receive copies directly or indirectly through you, then
the only way you could satisfy both it and this License would be to
refrain entirely from distribution of the Program.

If any portion of this section is held invalid or unenforceable under
any particular circumstance, the balance of the section is intended to
apply and the section as a whole is intended to apply in other
circumstances.

It is not the purpose of this section to induce you to infringe any
patents or other property right claims or to contest validity of any
such claims; this section has the sole purpose of protecting the
integrity of the free software distribution system, which is
implemented by public license practices.  Many people have made
generous contributions to the wide range of software distributed
through that system in reliance on consistent application of that
system; it is up to the author/donor to decide if he or she is willing
to distribute software through any other system and a licensee cannot
impose that choice.

This section is intended to make thoroughly clear what is believed to
be a consequence of the rest of this License.

@item
If the distribution and/or use of the Program is restricted in
certain countries either by patents or by copyrighted interfaces, the
original copyright holder who places the Program under this License
may add an explicit geographical distribution limitation excluding
those countries, so that distribution is permitted only in or among
countries not thus excluded.  In such case, this License incorporates
the limitation as if written in the body of this License.

@item
The Free Software Foundation may publish revised and/or new versions
of the General Public License from time to time.  Such new versions will
be similar in spirit to the present version, but may differ in detail to
address new problems or concerns.

Each version is given a distinguishing version number.  If the Program
specifies a version number of this License which applies to it and ``any
later version'', you have the option of following the terms and conditions
either of that version or of any later version published by the Free
Software Foundation.  If the Program does not specify a version number of
this License, you may choose any version ever published by the Free Software
Foundation.

@item
If you wish to incorporate parts of the Program into other free
programs whose distribution conditions are different, write to the author
to ask for permission.  For software which is copyrighted by the Free
Software Foundation, write to the Free Software Foundation; we sometimes
make exceptions for this.  Our decision will be guided by the two goals
of preserving the free status of all derivatives of our free software and
of promoting the sharing and reuse of software generally.

@iftex
@heading NO WARRANTY
@end iftex
@ifinfo
@center NO WARRANTY
@end ifinfo

@item
BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
PROVIDE THE PROGRAM ``AS IS'' WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
REPAIR OR CORRECTION.

@item
IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.
@end enumerate

@iftex
@heading END OF TERMS AND CONDITIONS
@end iftex
@ifinfo
@center END OF TERMS AND CONDITIONS
@end ifinfo

@page
@unnumberedsec Appendix: How to Apply These Terms to Your New Programs

  If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these terms.

  To do so, attach the following notices to the program.  It is safest
to attach them to the start of each source file to most effectively
convey the exclusion of warranty; and each file should have at least
the ``copyright'' line and a pointer to where the full notice is found.

@smallexample
@var{one line to give the program's name and a brief idea of what it does.}
Copyright (C) @var{yyyy}  @var{name of author}

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
@end smallexample

Also add information on how to contact you by electronic and paper mail.

If the program is interactive, make it output a short notice like this
when it starts in an interactive mode:

@smallexample
Gnomovision version 69, Copyright (C) 19@var{yy} @var{name of author}
Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
This is free software, and you are welcome to redistribute it
under certain conditions; type `show c' for details.
@end smallexample

The hypothetical commands @samp{show w} and @samp{show c} should show
the appropriate parts of the General Public License.  Of course, the
commands you use may be called something other than @samp{show w} and
@samp{show c}; they could even be mouse-clicks or menu items---whatever
suits your program.

You should also get your employer (if you work as a programmer) or your
school, if any, to sign a ``copyright disclaimer'' for the program, if
necessary.  Here is a sample; alter the names:

@example
Yoyodyne, Inc., hereby disclaims all copyright interest in the program
`Gnomovision' (which makes passes at compilers) written by James Hacker.

@var{signature of Ty Coon}, 1 April 1989
Ty Coon, President of Vice
@end example

This General Public License does not permit incorporating your program into
proprietary programs.  If your program is a subroutine library, you may
consider it more useful to permit linking proprietary applications with the
library.  If this is what you want to do, use the GNU Library General
Public License instead of this License.


@menu
* GNU Free Documentation License::  
@end menu

@node GNU Free Documentation License,  , Copying, Copying
@appendixsec GNU Free Documentation License

@cindex FDL, GNU Free Documentation License
@center Version 1.2, November 2002

@display
Copyright @copyright{} 2000,2001,2002 Free Software Foundation, Inc.
59 Temple Place, Suite 330, Boston, MA  02111-1307, USA

Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
@end display

@enumerate 0
@item
PREAMBLE

The purpose of this License is to make a manual, textbook, or other
functional and useful document @dfn{free} in the sense of freedom: to
assure everyone the effective freedom to copy and redistribute it,
with or without modifying it, either commercially or noncommercially.
Secondarily, this License preserves for the author and publisher a way
to get credit for their work, while not being considered responsible
for modifications made by others.

This License is a kind of ``copyleft'', which means that derivative
works of the document must themselves be free in the same sense.  It
complements the GNU General Public License, which is a copyleft
license designed for free software.

We have designed this License in order to use it for manuals for free
software, because free software needs free documentation: a free
program should come with manuals providing the same freedoms that the
software does.  But this License is not limited to software manuals;
it can be used for any textual work, regardless of subject matter or
whether it is published as a printed book.  We recommend this License
principally for works whose purpose is instruction or reference.

@item
APPLICABILITY AND DEFINITIONS

This License applies to any manual or other work, in any medium, that
contains a notice placed by the copyright holder saying it can be
distributed under the terms of this License.  Such a notice grants a
world-wide, royalty-free license, unlimited in duration, to use that
work under the conditions stated herein.  The ``Document'', below,
refers to any such manual or work.  Any member of the public is a
licensee, and is addressed as ``you''.  You accept the license if you
copy, modify or distribute the work in a way requiring permission
under copyright law.

A ``Modified Version'' of the Document means any work containing the
Document or a portion of it, either copied verbatim, or with
modifications and/or translated into another language.

A ``Secondary Section'' is a named appendix or a front-matter section
of the Document that deals exclusively with the relationship of the
publishers or authors of the Document to the Document's overall
subject (or to related matters) and contains nothing that could fall
directly within that overall subject.  (Thus, if the Document is in
part a textbook of mathematics, a Secondary Section may not explain
any mathematics.)  The relationship could be a matter of historical
connection with the subject or with related matters, or of legal,
commercial, philosophical, ethical or political position regarding
them.

The ``Invariant Sections'' are certain Secondary Sections whose titles
are designated, as being those of Invariant Sections, in the notice
that says that the Document is released under this License.  If a
section does not fit the above definition of Secondary then it is not
allowed to be designated as Invariant.  The Document may contain zero
Invariant Sections.  If the Document does not identify any Invariant
Sections then there are none.

The ``Cover Texts'' are certain short passages of text that are listed,
as Front-Cover Texts or Back-Cover Texts, in the notice that says that
the Document is released under this License.  A Front-Cover Text may
be at most 5 words, and a Back-Cover Text may be at most 25 words.

A ``Transparent'' copy of the Document means a machine-readable copy,
represented in a format whose specification is available to the
general public, that is suitable for revising the document
straightforwardly with generic text editors or (for images composed of
pixels) generic paint programs or (for drawings) some widely available
drawing editor, and that is suitable for input to text formatters or
for automatic translation to a variety of formats suitable for input
to text formatters.  A copy made in an otherwise Transparent file
format whose markup, or absence of markup, has been arranged to thwart
or discourage subsequent modification by readers is not Transparent.
An image format is not Transparent if used for any substantial amount
of text.  A copy that is not ``Transparent'' is called ``Opaque''.

Examples of suitable formats for Transparent copies include plain
@sc{ascii} without markup, Texinfo input format, La@TeX{} input
format, @acronym{SGML} or @acronym{XML} using a publicly available
@acronym{DTD}, and standard-conforming simple @acronym{HTML},
PostScript or @acronym{PDF} designed for human modification.  Examples
of transparent image formats include @acronym{PNG}, @acronym{XCF} and
@acronym{JPG}.  Opaque formats include proprietary formats that can be
read and edited only by proprietary word processors, @acronym{SGML} or
@acronym{XML} for which the @acronym{DTD} and/or processing tools are
not generally available, and the machine-generated @acronym{HTML},
PostScript or @acronym{PDF} produced by some word processors for
output purposes only.

The ``Title Page'' means, for a printed book, the title page itself,
plus such following pages as are needed to hold, legibly, the material
this License requires to appear in the title page.  For works in
formats which do not have any title page as such, ``Title Page'' means
the text near the most prominent appearance of the work's title,
preceding the beginning of the body of the text.

A section ``Entitled XYZ'' means a named subunit of the Document whose
title either is precisely XYZ or contains XYZ in parentheses following
text that translates XYZ in another language.  (Here XYZ stands for a
specific section name mentioned below, such as ``Acknowledgements'',
``Dedications'', ``Endorsements'', or ``History''.)  To ``Preserve the Title''
of such a section when you modify the Document means that it remains a
section ``Entitled XYZ'' according to this definition.

The Document may include Warranty Disclaimers next to the notice which
states that this License applies to the Document.  These Warranty
Disclaimers are considered to be included by reference in this
License, but only as regards disclaiming warranties: any other
implication that these Warranty Disclaimers may have is void and has
no effect on the meaning of this License.

@item
VERBATIM COPYING

You may copy and distribute the Document in any medium, either
commercially or noncommercially, provided that this License, the
copyright notices, and the license notice saying this License applies
to the Document are reproduced in all copies, and that you add no other
conditions whatsoever to those of this License.  You may not use
technical measures to obstruct or control the reading or further
copying of the copies you make or distribute.  However, you may accept
compensation in exchange for copies.  If you distribute a large enough
number of copies you must also follow the conditions in section 3.

You may also lend copies, under the same conditions stated above, and
you may publicly display copies.

@item
COPYING IN QUANTITY

If you publish printed copies (or copies in media that commonly have
printed covers) of the Document, numbering more than 100, and the
Document's license notice requires Cover Texts, you must enclose the
copies in covers that carry, clearly and legibly, all these Cover
Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on
the back cover.  Both covers must also clearly and legibly identify
you as the publisher of these copies.  The front cover must present
the full title with all words of the title equally prominent and
visible.  You may add other material on the covers in addition.
Copying with changes limited to the covers, as long as they preserve
the title of the Document and satisfy these conditions, can be treated
as verbatim copying in other respects.

If the required texts for either cover are too voluminous to fit
legibly, you should put the first ones listed (as many as fit
reasonably) on the actual cover, and continue the rest onto adjacent
pages.

If you publish or distribute Opaque copies of the Document numbering
more than 100, you must either include a machine-readable Transparent
copy along with each Opaque copy, or state in or with each Opaque copy
a computer-network location from which the general network-using
public has access to download using public-standard network protocols
a complete Transparent copy of the Document, free of added material.
If you use the latter option, you must take reasonably prudent steps,
when you begin distribution of Opaque copies in quantity, to ensure
that this Transparent copy will remain thus accessible at the stated
location until at least one year after the last time you distribute an
Opaque copy (directly or through your agents or retailers) of that
edition to the public.

It is requested, but not required, that you contact the authors of the
Document well before redistributing any large number of copies, to give
them a chance to provide you with an updated version of the Document.

@item
MODIFICATIONS

You may copy and distribute a Modified Version of the Document under
the conditions of sections 2 and 3 above, provided that you release
the Modified Version under precisely this License, with the Modified
Version filling the role of the Document, thus licensing distribution
and modification of the Modified Version to whoever possesses a copy
of it.  In addition, you must do these things in the Modified Version:

@enumerate A
@item
Use in the Title Page (and on the covers, if any) a title distinct
from that of the Document, and from those of previous versions
(which should, if there were any, be listed in the History section
of the Document).  You may use the same title as a previous version
if the original publisher of that version gives permission.

@item
List on the Title Page, as authors, one or more persons or entities
responsible for authorship of the modifications in the Modified
Version, together with at least five of the principal authors of the
Document (all of its principal authors, if it has fewer than five),
unless they release you from this requirement.

@item
State on the Title page the name of the publisher of the
Modified Version, as the publisher.

@item
Preserve all the copyright notices of the Document.

@item
Add an appropriate copyright notice for your modifications
adjacent to the other copyright notices.

@item
Include, immediately after the copyright notices, a license notice
giving the public permission to use the Modified Version under the
terms of this License, in the form shown in the Addendum below.

@item
Preserve in that license notice the full lists of Invariant Sections
and required Cover Texts given in the Document's license notice.

@item
Include an unaltered copy of this License.

@item
Preserve the section Entitled ``History'', Preserve its Title, and add
to it an item stating at least the title, year, new authors, and
publisher of the Modified Version as given on the Title Page.  If
there is no section Entitled ``History'' in the Document, create one
stating the title, year, authors, and publisher of the Document as
given on its Title Page, then add an item describing the Modified
Version as stated in the previous sentence.

@item
Preserve the network location, if any, given in the Document for
public access to a Transparent copy of the Document, and likewise
the network locations given in the Document for previous versions
it was based on.  These may be placed in the ``History'' section.
You may omit a network location for a work that was published at
least four years before the Document itself, or if the original
publisher of the version it refers to gives permission.

@item
For any section Entitled ``Acknowledgements'' or ``Dedications'', Preserve
the Title of the section, and preserve in the section all the
substance and tone of each of the contributor acknowledgements and/or
dedications given therein.

@item
Preserve all the Invariant Sections of the Document,
unaltered in their text and in their titles.  Section numbers
or the equivalent are not considered part of the section titles.

@item
Delete any section Entitled ``Endorsements''.  Such a section
may not be included in the Modified Version.

@item
Do not retitle any existing section to be Entitled ``Endorsements'' or
to conflict in title with any Invariant Section.

@item
Preserve any Warranty Disclaimers.
@end enumerate

If the Modified Version includes new front-matter sections or
appendices that qualify as Secondary Sections and contain no material
copied from the Document, you may at your option designate some or all
of these sections as invariant.  To do this, add their titles to the
list of Invariant Sections in the Modified Version's license notice.
These titles must be distinct from any other section titles.

You may add a section Entitled ``Endorsements'', provided it contains
nothing but endorsements of your Modified Version by various
parties---for example, statements of peer review or that the text has
been approved by an organization as the authoritative definition of a
standard.

You may add a passage of up to five words as a Front-Cover Text, and a
passage of up to 25 words as a Back-Cover Text, to the end of the list
of Cover Texts in the Modified Version.  Only one passage of
Front-Cover Text and one of Back-Cover Text may be added by (or
through arrangements made by) any one entity.  If the Document already
includes a cover text for the same cover, previously added by you or
by arrangement made by the same entity you are acting on behalf of,
you may not add another; but you may replace the old one, on explicit
permission from the previous publisher that added the old one.

The author(s) and publisher(s) of the Document do not by this License
give permission to use their names for publicity for or to assert or
imply endorsement of any Modified Version.

@item
COMBINING DOCUMENTS

You may combine the Document with other documents released under this
License, under the terms defined in section 4 above for modified
versions, provided that you include in the combination all of the
Invariant Sections of all of the original documents, unmodified, and
list them all as Invariant Sections of your combined work in its
license notice, and that you preserve all their Warranty Disclaimers.

The combined work need only contain one copy of this License, and
multiple identical Invariant Sections may be replaced with a single
copy.  If there are multiple Invariant Sections with the same name but
different contents, make the title of each such section unique by
adding at the end of it, in parentheses, the name of the original
author or publisher of that section if known, or else a unique number.
Make the same adjustment to the section titles in the list of
Invariant Sections in the license notice of the combined work.

In the combination, you must combine any sections Entitled ``History''
in the various original documents, forming one section Entitled
``History''; likewise combine any sections Entitled ``Acknowledgements'',
and any sections Entitled ``Dedications''.  You must delete all
sections Entitled ``Endorsements.''

@item
COLLECTIONS OF DOCUMENTS

You may make a collection consisting of the Document and other documents
released under this License, and replace the individual copies of this
License in the various documents with a single copy that is included in
the collection, provided that you follow the rules of this License for
verbatim copying of each of the documents in all other respects.

You may extract a single document from such a collection, and distribute
it individually under this License, provided you insert a copy of this
License into the extracted document, and follow this License in all
other respects regarding verbatim copying of that document.

@item
AGGREGATION WITH INDEPENDENT WORKS

A compilation of the Document or its derivatives with other separate
and independent documents or works, in or on a volume of a storage or
distribution medium, is called an ``aggregate'' if the copyright
resulting from the compilation is not used to limit the legal rights
of the compilation's users beyond what the individual works permit.
When the Document is included in an aggregate, this License does not
apply to the other works in the aggregate which are not themselves
derivative works of the Document.

If the Cover Text requirement of section 3 is applicable to these
copies of the Document, then if the Document is less than one half of
the entire aggregate, the Document's Cover Texts may be placed on
covers that bracket the Document within the aggregate, or the
electronic equivalent of covers if the Document is in electronic form.
Otherwise they must appear on printed covers that bracket the whole
aggregate.

@item
TRANSLATION

Translation is considered a kind of modification, so you may
distribute translations of the Document under the terms of section 4.
Replacing Invariant Sections with translations requires special
permission from their copyright holders, but you may include
translations of some or all Invariant Sections in addition to the
original versions of these Invariant Sections.  You may include a
translation of this License, and all the license notices in the
Document, and any Warranty Disclaimers, provided that you also include
the original English version of this License and the original versions
of those notices and disclaimers.  In case of a disagreement between
the translation and the original version of this License or a notice
or disclaimer, the original version will prevail.

If a section in the Document is Entitled ``Acknowledgements'',
``Dedications'', or ``History'', the requirement (section 4) to Preserve
its Title (section 1) will typically require changing the actual
title.

@item
TERMINATION

You may not copy, modify, sublicense, or distribute the Document except
as expressly provided for under this License.  Any other attempt to
copy, modify, sublicense or distribute the Document is void, and will
automatically terminate your rights under this License.  However,
parties who have received copies, or rights, from you under this
License will not have their licenses terminated so long as such
parties remain in full compliance.

@item
FUTURE REVISIONS OF THIS LICENSE

The Free Software Foundation may publish new, revised versions
of the GNU Free Documentation License from time to time.  Such new
versions will be similar in spirit to the present version, but may
differ in detail to address new problems or concerns.  See
@uref{http://www.gnu.org/copyleft/}.

Each version of the License is given a distinguishing version number.
If the Document specifies that a particular numbered version of this
License ``or any later version'' applies to it, you have the option of
following the terms and conditions either of that specified version or
of any later version that has been published (not as a draft) by the
Free Software Foundation.  If the Document does not specify a version
number of this License, you may choose any version ever published (not
as a draft) by the Free Software Foundation.
@end enumerate

@page
@appendixsubsec ADDENDUM: How to use this License for your documents

To use this License in a document you have written, include a copy of
the License in the document and put the following copyright and
license notices just after the title page:

@smallexample
@group
  Copyright (C)  @var{year}  @var{your name}.
  Permission is granted to copy, distribute and/or modify this document
  under the terms of the GNU Free Documentation License, Version 1.2
  or any later version published by the Free Software Foundation;
  with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
  Texts.  A copy of the license is included in the section entitled ``GNU
  Free Documentation License''.
@end group
@end smallexample

If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts,
replace the ``with...Texts.'' line with this:

@smallexample
@group
    with the Invariant Sections being @var{list their titles}, with
    the Front-Cover Texts being @var{list}, and with the Back-Cover Texts
    being @var{list}.
@end group
@end smallexample

If you have Invariant Sections without Cover Texts, or some other
combination of the three, merge those two alternatives to suit the
situation.

If your document contains nontrivial examples of program code, we
recommend releasing these examples in parallel under your choice of
free software license, such as the GNU General Public License,
to permit their use in free software.

@c Local Variables:
@c ispell-local-pdict: "ispell-dict"
@c End:


@node Index,  , Copying, Top
@unnumbered Index

@printindex cp

@bye

