\input texinfo   @c -*-texinfo-*-

@c The original files are xaos.geninfo and xaos.hlp. xaos.texinfo is
@c automatically generated. So make all changes in the orignal files please.
@c To regenerate xaos.texinfo, please run "mktexinfo".

@c Use A4 paper - If you don't like that, remove the following 3 lines.
@iftex
@afourpaper
@end iftex

@setfilename xaos.info
@settitle An fast realtime interactive fractal zoomer --- user's manual
@dircategory Graphics
@direntry 
 * XaoS: (xaos).               A fast real-time interactive fractal zoomer
@end direntry


@ifinfo
@copyright{} 1996-2006 Jan Hubicka and the XaoS Development Team

Permission is granted to make and distribute verbatim
copies of this manual provided the copyright notice and
this permission notice are preserved on all copies.

@end ifinfo

@c %**end of header

@set VERSION    3.2
@set DATE       Jan 23, 2006

@titlepage

@title{XaoS @value{VERSION}}
@subtitle{A fast real-time interactive fractal zoomer --- User's manual}

@author{Jan Hubi@v cka}
@tex
Dukelsk\'ych bojovn\'\i ku 1944 
@end tex
@*
390 03 T@'abor @*
Czech Republic

Email: @code{jh@@ucw.cz}

@value{DATE}

@page
@vskip 0pt plus 1filll
@vskip 0pt plus 1filll

@copyright{} 1996-2006 @tex Jan Hubi\v cka and the XaoS Development Team
@end tex

Permission is granted to make and distribute verbatim
copies of this manual provided the copyright notice and
this permission notice are preserved on all copies.

@end titlepage

@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@node   Top,    Overview,       (dir),  (dir)

@ifinfo
@top XaoS @value{VERSION}
@flushright 1.0
A real-time interactive fractal zoomer
User's manual
@value{DATE}
@end flushright

This manual contains user documentation about XaoS --- a fast real-time fractal
zoomer. XaoS uses a development model, so sources are freely available. The
file @code{xaosdev.texinfo} in the source documentation contains a hacker's
manual (design overview, algorithm description etc.).
@end ifinfo

@menu
* Overview::		What does this software do then?
* tutorial::		XaoS tutorial
* controls::		Basic controls
* mpeg::		How to encode MPEG files
* format::		XaoS's file format description
* writehelp::		How to write XaoS help files
* xshl::		XaoS simple hypertext language
* drivers::		Driver specific documentation
* menus::		Functions, menu items and command line parameters
* authors::		Credits
* lists::		Mailing lists
* index::		Function index
@end menu


@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@node Overview, tutorial, Top, Top

@chapter Overview
@menu
* Why?::		Why yet another fractal generator?
* What?::		What does this software do then?
@end menu

@node Why?, What?, Overview, Overview
@section Why yet another fractal generator?


We decided to make XaoS, because all fractal browsers we know of take a
long time to calculate each image. You may browse nice images
generated by them but real impressions of fractals --- the self
similarity and infinite zooming into the nice parts of fractals ---
can be seen only in animations. There are many programs available that
make nice animations, but they take a long time to calculate and lots
of space on disk. Most such animations are quite ugly because their
authors can't see them without many hours of calculations.

A natural question is: is it possible to generate such animations in
real-time? The answer was negative for many years, since the Mandelbrot set is
very computationally expensive. Things are changing. Today's computers
are fast enough to calculate approx. 10.000 of pixels per frame,
which is enough 
for a very low resolution animation (100x100). Several programs doing that
are available. But 100x100 animation still looks quite ugly. To make
animation nice you need at least 320x200 pixels. And that is 6 times more!
One possibility is to wait until computers will be fast enough, but
it will take many years, and then 320x200 animations will be obsolete
and everyone will want 1024x768 resolution instead or more.

We found a special algorithm that saves up to 99.98% of calculations during
zooming by reusing pixels already calculated in previous frames. There were
some programs doing similiar tricks before but we don't know about any able
to do zooming interactively with a speed similar to XaoS. Many other tricks
were later implemented XaoS to achieve yet higher framerates. Now XaoS does
up to 120 frames per second on a 120Mhz pentium in a fullscreen 320x200
animation, and calculates an average of 160 (0.24%) pixels per frame. This makes
XaoS fast enough to achieve its primary goal, realtime animation, but there
are still many areas that could improve, since more complex fractals,
higher resolutions, or slower computers still bring many problems.

@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@node What?, , Why?, Overview
@comment  node-name,  next,      previous,  up
@section What does this software do then?

XaoS is a realtime interactive fractal zoomer. This means that it lets you
zoom smoothly into any place in the fractal you choose without the many hours
of calculation required by most other fractal generators. It now has many
other features too, like 13 different fractal types, autopilot, special coloring
modes, support for various bit depths (8bpp, truecolor, hicolor and realcolor),
random palette generation, color cycling etc...

@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@node tutorial, controls, Overview, Top

@chapter XaoS tutorial

This is a brief introduction to the basic XaoS features.

@section How to zoom
The main advantage of XaoS is that after a few seconds' delay to calculate
the first image, you may choose any point with the mouse and press the @emph{left} button.
The image will start to zoom smoothly into the point you choose. You may move
the mouse and zoom smoothly into interesting areas. By pressing the @emph{middle
button} (or @emph{left+right} buttons) you may also
@emph{move the image} using ``drag & drop'' if you missed an interesting
place. @emph{Unzooming} is also possible by using the @emph{right button},
but it is much slower because optimizations are not so effective as for zooming.

In case you think that the default @emph{speed} is boring (it is quite slow, to
make XaoS smooth on a slow computer) you may change it by pressing @emph{arrow
up/down}. But faster zooming is more expensive, so if the speed is too high
you will see little but funny colorful blinking rectangles.

@section Autopilot

To make XaoS yet more impressive we made a special autopilot that
automatically drives into interesting boundaries of the set. So you can
press @code{A}, play your favorite music, drink coffee and relax. I never
tried this but it should be really relaxing! Many pictures in the XaoS
gallery were discovered using the autopilot.

The autopilot also has some additional features. It turns back when the
zoomed picture stops being interesting, and is able to spot when it's zoomed
into a really boring part (or has reached the limit of floating point
numbers) and restart zooming from the top.

@section Various fractal formulae

XaoS also supports formulae other than the Mandelbrot set. You may change
@emph{formula} using the @emph{number keys}
or @emph{SHIFT+letters}.



On keys @code{1} to @code{5} are @emph{Mandelbrot sets of various power}. The ``normal''
Mandelbrot set is on key @code{1}.

On key @code{6} is a fractal called @emph{Newton}. It is Newton's famous formula for finding roots.

On key @code{7} is the @emph{fourth ordered Newton} fractal.

On key @code{8} is a fractal called @emph{Barnsley}.

On key @code{9} is @emph{Barnsley's second} fractal.

On key @code{0} is @emph{Barnsley's third} fractal.

With keys @code{SHIFT-A} you can display a fractal called @emph{octo}. It is a fractal that Thomas
discovered in fractint.

With keys @code{SHIFT-B} you can display a fractal called @emph{Phoenix}. It is a very nice and quite famous fractal.

With keys @code{SHIFT-C} you can display a fractal called @emph{Magnet}. This fractal has quite a complex formula so it is
a bit slow.

With keys @code{SHIFT-D} you can display the @emph{Magnet2} fractal.

The rest of the built-in fractals are accessible through an other menu, but
you can still use the hotkeys.

On @code{SHIFT-E} is a fractal called @emph{Triceratops} found by Arpad.

On @code{SHIFT-F} is a fractal called @emph{Catseye} found by Arpad.
This is more interesting if you change the bailout value.

On @code{SHIFT-G} is a fractal called @emph{Mandelbar}. It was in
Gnofract4d, and they found it at:
http://mathworld.wolfram.com/MandelbarSet.html

On @code{SHIFT-H} is the @emph{Lambda} fractal.

On @code{SHIFT-I} and @code{SHIFT-J} are the @emph{Manowar}
and @emph{Spider} fractals, they were found by users of fractint.
(Scott Taylor or Lee Skinner)
It was on http://spanky.triumf.ca/www/fractint/
taylor_skinner_type.html

The next 3 fractals are famous classic fractals.

On @code{SHIFT-K} is the @emph{Sierpinski} Gasket.
You can change its shape by selecting another Julia seed.
(This is for technical reasons.)

On @code{SHIFT-L} is the @emph{Sierpinski Carpet.}
It's shape can also be changed by selecting another Julia seed.

On @code{SHIFT-M} is the @emph{Koch Snowflake.}



@section Out-coloring modes

To make fractals yet more interesting, more coloring modes for points
outside the set are provided. ``Classical coloring mode'' uses the number of
iterations that the orbit required to escape to (nearly) infinity. You can change this
mode from the @emph{Fractal menu} or by pressing key @code{C}
To see more about coloring modes, try the tutorial on Incoloring modes from the XaoS features overview.

Those cryptic names for coloring modes are mathematical formulae, where @emph{iter} means number
of iterations, @emph{real} means real coordinate of last orbit, and @emph{imag} means imaginary
coordinate of last orbit.

@section In-coloring mode

In-coloring mode is similar to out-coloring, except that it changes how
things inside the set are displayed. This can also be changed from the @emph{fractal
menu} or by pressing @code{F}.

You might also want to see the tutorial on
Out-coloring modes from the XaoS features overview.

@section Planes

All fractals displayed by XaoS are functions with a complex parameter. It
can be displayed in the normal complex plane, where x is the real part of
the number, and y is the imaginary part; but it can also be displayed in
a number of other planes. You can select the plane to use from the
@emph{Fractal menu}, or by pressing @code{I}.

Like the coloring modes, planes have cryptic names. You guessed it, they're
mathematical formulae. Here @code{mu} means coordinates in the normal
complex plane. If you have coordinates in @code{1/mu} plane, and you need
coordinates in the a complex plane (to calculate the Mandelbrot set) you
simply use the coordinates as mu. Lambda is another plane that can be
converted to mu using a similar formula.

@table @strong
@item mu
normal mode.

@item 1/mu
Inversion: infinity goes to 0 and 0 goes to infinity.

@item 1/(mu+0.25)
Similar to inversion, but moves the center outside of the
Mandelbrot set so that it looks parabolic.

@item lambda
Lambda plane.

@item 1/lambda
Inversion of lambda plane.

@item 1/lambda-1
Inversion with moved center.

@item 1/(mu-1.40115)
A very interesting mode for the Mandelbrot set. It makes small things
big, so you can browse the set's details easily.
@end table


@section Mandelbrot/Julia switching

Most of the fractals displayed by XaoS (currently all of them) have two
forms: Mandelbrot and Julia. Every point in a Mandelbrot set has its
own Julia set. To see more about this correspondence, try the tutorial on
Julia set from the Introduction to fractals.

In the Mandelbrot mode, you can get a corresponding Julia by moving the mouse
to an interesting point and pressing @code{M}. To get back press @code{M}
again. Some fractals (Barnsley and phoenix) are already in their Julia
versions, because the Mandelbrot ones are boring. But by pressing @code{M}
in such fractal you should get the Mandelbrot version, and by choosing another
point as the base point and pressing @code{M} again you should get a
completely different fractal. The most interesting points for Julia sets
are at the boundaries of the Mandelbrot set. Most of the Julias inside or
outside the set are boring.


@section Fast Julia preview mode

Fast Julia mode is a quick way to find a point to use as a base for the Julia
set.. Just press @code{J} and a small Julia set will be displayed in the top
left corner. Then move the mouse around with button 1 depressed, and the Julia
for the point the mouse is over will be automatically generated.

@section Palette

If you think that the default XaoS colors are ugly or you are just
bored by them you can change it by pressing @code{P}. XaoS will
automatically generate random palettes. Many of them look ugly, so
press @code{P} again to get another one until you find one you like.

@section Filters

Many interesting effects are done by post-calculation filters. @xref{filter}.
XaoS has filters that do everything from embossing, through motion-blurring,
right through to turning the fractal into a stereogram. To enable them use
the @code{filter menu} or press @code{E}.

@section Palette cycling

This is a very old trick that makes the Mandelbrot set a little flashier. You
may enable or disable it using @code{Y}. In the truecolor modes you need
to enable the palette emulator filter first. This is done
via the @code{E} key, or from the filter menu.

@section Changing number of iterations

To calculate fractals perfectly, you need an infinite number of
iterations. XaoS does just the first few of them, so after lots of zooming
you may get into a place that looks quite boring, and the boundaries of the
set are rounded, without any interesting details. This can be changed by
changing the number of iterations:

Press and hold @code{arrow right} and wait until iterations are high enough.
This may slow down calculation much. To reduce number of iterations
press @code{arrow left}.

@section Changing resolution

XaoS usually starts in a low resolution (320x200 or thereabouts) to make
calculations faster. If you have a fast computer or you need to
save bigger @code{.gif} images, you may change the resolution. This
can be done by pressing @code{=} in the full screen drivers, or simply
by resizing the XaoS window.

@section Changing driver

XaoS usually has more than one driver available. You may change it on
the fly in case you want a different one. For example, XaoS started in X11
can be switched at runtime to use the AA driver. This can be done from the
UI menu.

This action is bit dangerous, because XaoS can crash during initialization
if there is some problem with initialization; XaoS tries to initialize a new
driver, and if it fails it attempts to return back to the original. Sometimes
this is impossible, and all XaoS can do is terminate..

@section Other features
XaoS has many other features, but they don't fit into this tutorial. Most of
them are available from the menu, so you can experiment with them. You might
also want to see the @emph{animated tutorials} from the @emph{help menu},
to have an idea what XaoS can do.


@c ## chapter tutorial ##

@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@comment  node-name,  next,      previous,  up
@node controls, mpeg, tutorial ,Top

@chapter Basic controls
By default the mouse buttons work in the following way:

@table @strong
@item left
zoom in
@item right
zoom out
@item middle
move fractal in a drag-and-drop fashion
@end table

This behavior can change. If you enable rotation, the first button is used for rotating
fractals. Also, in fast Julia mode, the first button is used to change the seed.

If you don't have a middle button, press both buttons to enable
emulation.

After few minutes of zooming you will probably exceed the precision and the
fractals will get boring. If you are getting strange big rectangles on the screen,
you probably reached the numeric limit: there is no way to avoid this except
un-zoom back and choose a different area. It doesn't hurt so much, since you have
zoomed approximately 64 051 194 700 380 384 times, so there are quite a lot of areas to
explore. Algorithms with unlimited precision exist, but they are still too
slow for real-time zooming.

The other possibility is that you have reached the iteration limit. The fractal is
calculated approximately, and in this case you need to increase number of
iterations used for approximation (and decrease the speed in the process).
This is done from the menu or using the arrow keys @emph{Left} and @emph{Right}.

An @emph{Up} and @emph{Down} keys should be used to change zooming
speed. Note that higher speed costs more and image will be blocky.

This behavior can also change. With palette cycling enabled, @emph{Left}
and @emph{Right} keys change cycling speed; in continuous
rotation they change rotation speed.

All other functions are available from the menu, which (in the default
configuration) are displayed when you move the mouse to the top of the
screen/window. It is useful to learn the shortcut keys, which are
shown in gray next to the menu items they trigger.


@c ## chapter controls ##


@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@comment  node-name,  next,      previous,  up
@node mpeg, format, controls ,Top


@chapter How to encode MPEG files from XaoS

To save a sequence, make a @code{xaf} file first (the easiest way to do this is
to use the @emph{record} function in the file menu). Then you need to render
the sequence. XaoS can output sequences of ordinary @code{PNG} images, that
can later be used by an MPEG encoder.

@section Generating sequences for MPEG

To encode a sequence, use the following command:


@example
xaos -render [filename] -size 352x240 -antialiasing
-renderframerate 24 -basename [basename]
@end example


@code{[filename]} is the name of the @code{xaf} file,
@code{[basename]} is the name used as the base for rendered images.
XaoS adds a four digit number and extension automatically.

You might also want to change the resolution. 352x240 is the default size
for MPEG files, but other sizes work as well. Each dimension must be a multiple
of 16.

The framerate can also be altered. MPEG supports only a few selected framerates
(namely 23.976, 24, 25, 29.97, 30) and you can pick any of them.

@code{-antialiasing} is used to produce anti-aliased images. It takes a much longer
time and much more memory to calculate them, but resulting images are better
for MPEG DCT compression and they are @emph{compressed about 3 times more}.
(the same is true of @emph{JPEG images})

At the other hand, the other XaoS rendering option @code{-alwaysrecalc} (which disables
XaoS's zooming optimizations) is @emph{not recommended}. If that's used, the
sequence of animation then contains quite a lot of extra information, which
increases size of MPEG file, but because of MPEG's lossy compression it is hard
to see any difference. So it don't worth it.
@section Rendered files
Once you start it, XaoS will generate thousands of frames. They take quite
a long time to calculate and save, and consume plenty of disk space.
(e.g. to render part 1 of the tutorial you need about 60MB and half an hour of time).

All images are named @code{[basename]framenum.png}. For example @code{intro0001.png} is
the first frame of the animation intro. If consecutive frames are the same, XaoS
doesn't save them, so some frames may be missing. If your encoder can't handle
that, you will need to write a simple script which will fill in the gaps by means
of @code{mv} or symbolic linking.

A list of all filenames is saved into the file @code{[basename].par}, where each line is
the name of one frame. The names repeat here if necessary, so you can use this
file to supply filenames to the encoder.

@section Pattern file

Some other files are generated as well. A @emph{pattern file} is generated,
which contains a @emph{recommended order of P, B and I frames}.

MPEG sequence consist of these three frames. The @emph{I frames} are just images
saved in a format similar to JPEG files.

The @emph{P frames} are images which are constructed as a delta from the
previous one (the latest I or P frame). In case consecutive frames are similar
(and in animations they often are), a P frame takes much less disk space
than an I frame.

The @emph{B frames} are constructed from the nearest previous P or I frame
and the next P or I frame. They take even less disk space, but they are quite
hard to encode. Also they are @emph{not used as previous frames},
so their information is lost once they are displayed. They are usually
rendered at lower quality than a P or I frame and used just to interpolate
nearest frame and make animation smoother. It is generally not a good idea
to make a whole sequence just from B frames.

Using just P frames is generally not a good idea. It makes the file shorter,
but to jump into Nth frame of animation you need to @emph{recalculate all P and B frames
since latest I frame}. Decoders often want to jump to some frame (when
the user asks, or when they can't decode a sequence in time and must skip
some), so you need to have some I frames in the animation to make this possible.
The latter reason means that you need to place them quite often. Usually
they are used for every 15th frame or thereabouts. Because they cost quite a lot,
in my animations I usually use every 27th frame. To set this distance
use @code{-iframedist} option. It should be a multiple of 3.

XaoS generates a recommended order of frames based on its knowledge of
fractal motion. Situations where the screen doesn't move at all are rendered
just from P frames (since jumping is usually not required here); in situations
where the screen changes completely (at least in XaoS's opinion) I frames are used
and in other cases, a standard sequence @code{IBBPBBPBBPBBP...} is used.

If your encoder supports this, you should supply this pattern for encoding to
squeeze out some bytes.

@section Motion vector files

XaoS also generates a motion vector recommendation for the encoder. This is
useful for encoding of B and P frames.

If some objects on the screen are moving at a constant speed, motion vectors
can store that speed, so no image needs to be saved to represent that change.

Calculating this motion vector is a very significant task. If you guess
them well, you increase quality and reduce file size, which is always great.
Calculation also takes lots of CPU and it is hard to get optimal vectors (it
just takes too long).

XaoS knows how the fractals move, so it can calculate this vectors quite
easily. XaoS saves this information into @code{*.p} and @code{*.b} files. (@code{*.p} are for P
frames, @code{*.b} are for B frames). If your encoder supports this, you should
provide this vector to increase quality. They are @code{not exact} (XaoS can make
mistakes); the encoder should try to find its own vectors, then try XaoS's ones,
and pick whichever is better.

This technique saves quite a lot of bytes in fast zooming/un-zooming
animations (where images move more than 3 or 5 pixels per frame---since
most programs look 10-20 pixels around each point for motion vectors).

To enable saving of motion vector files, add the option
@code{-rendervectors}.

@section Berkeley parallel MPEG encoder

This is the encoder I use. It seems to be the best freely available software
encoder I've tested. It can generate quite small files, but it is rather slow.
It is available at Berkeley's FTP site @code{mm-ftp.CS.Berkeley.EDU} and called
@code{mpeg_encode1.5b}

It has lots of options to tune, so you should spend quite a lot of time
playing with this. The configuration I use is in file @code{doc/mpeg.param}.

I've also made some patches that makes possible to use the pattern and motion
files generated from XaoS. The patch is in @code{doc/mpeg_encode.patch}. So if
you want to use these features (they are @emph{EXPERIMENTAL}) you might apply this
patch and recompile the encoder.

Once you filled the @code{mpeg.param} file (see comments inside), you should render
sequence using @code{mpeg_encode [filename]} and with luck you are done.





@c ## chapter mpeg ##

@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@comment  node-name,  next,      previous,  up
@node format, writehelp,mpeg ,Top
@chapter XaoS' file format
This section describes the format used by XaoS for animations, configuration
files and saved positions. All these files have a common format, designed
to be easily readable, to allow manual editing of files and easy conversion by
other programs.

I also taken care to make it easily extensible for future versions of XaoS
so I hope there will not be many incompatibilities between various XaoS
versions.

The format is a simple set of commands executed sequentially. XaoS does not provide
any variables/cycles as usual scripting languages do, but future extension to
full-blown Scheme should be easy since the format uses Scheme-like syntax.
The syntax of every command is:

@code{(command_name }@emph{[param1] [param2]}@code{)}

where parameters are optional and separated by whitespace (an arbitrary number
of spaces, tabs and newlines). The parameters can have the following types:

@table @strong
@item integer
number w/o decimal point (@code{123})
@item float
floating point number in decimal notation with optional exponent (@code{1.23E2})
@item keyword
text started by quote @code{'}. It is used to pass various string constants
like formula name (@code{'mandel}) Quote is required for scheme compatibility
@item string
Text inside double quotes. The only parameter that should contain whitespace
@item boolean
@code{#t} for true or @code{#f} for false
@end table

There is a complete description of all XaoS functions (with some examples) and an
index of functions in the XaoS registry. @xref{menus}. You may particularly want
to read about the animation functions. @xref{animf}. Also, the following functions
are significant:

@table @strong
@item load

This function loads and interprets a file. It works similarly to @code{#include}
in C.
@item initstate

Available in version 3.0 and above, this function resets XaoS' state to default
values. This command should be at the beginning of each animation file,
since otherwise some stuff previously enabled by user could cause unexpected
effects. State is not reset by default before playing animations since it would
make it impossible to write macros. Current versions don't really need macros, but
in future versions, when the Scheme programming language will be available, this
should be a much more interesting subject.
@item usleep

This function waits for a selected amount of time(in usec) before processing the
next command. The screen is recalculated and displayed at the beginning of
the sleep if necessary. The remaining time is spent by waiting, calculating if
necessary, or performing any animation you entered via animation commands.
@item wait

Waits until the animation or image rendering is complete. Do not call this
function when zoom, or continuous rotation is active otherwise deadlock happens. It is
a good idea to call it immediately before text subtitles are displayed, since it looks
ugly when they are displayed over a blocky unfinished fractal. Because the
degree of blockiness at a given instant is a function of your machine speed,
it may look nice for you but ugly for others with slower machines. Also
you should call this after an animation is performed, before the switch to another
fractal happens; since the switch involves calculation, the screen is stopped
for a while and an unfinished fractal there looks ugly.
You should also call it, when you want to do something as soon as possible.
@end table

Example:


@example
;configure everything for the first frame
(inistate)
(palette 1 1163254293 0) ;custom palette
(cycling #t) ;enable cycling
(cyclingspeed 7)
(maxiter 276) ;higher number of iterations
(range 3) ;default range for solid guessing
(usleep 1000000) ;second frame starts here
(moveview -1.8101154154614007889 -8.2687205907162041209E-05)
;just move the image
(usleep 1000000) ;third frame
(morphview -1.8101154154614007889 -8.2687205907162041209E-05
6.277210971069452361E-10 6.2772109785334669875E-10)
;10 seconds of zooming into selected
rectangle
(usleep 100000000)
@end example


The best way to learn XaoS command language is probably to read position files
and modify them. For example, to create zooming animation from the original
file:


@example
(initstate)
(defaultpalette 0)
(formula 'mandel)
(view -1.64128273713 -5.50393226816E-05 9.69332308848E-08
9.69332308834E-08)
@end example


Just change the @code{view} command to @code{morphview}, and add @code{usleep}:



@example
(initstate)
(defaultpalette 0)
(formula 'mandel)
(morphview -1.64128273713 -5.50393226816E-05 9.69332308848E-08
9.69332308834E-08)
(usleep 10000000)
@end example


The following code produces Julia morphing in the real axis:


@example
(initstate)
(fastjulia #t)
(juliaseed -2 0)
(morphjulia 2 0)
(usleep 2000000)
@end example



And following is the ``rotozooming'' animation:



@example
(initstate)
(fastrotate #t)
(morphview -1.64128273713 -5.50393226816E-05 9.69332308848E-08
9.69332308834E-08)
(morphangle 300)
(usleep 10000000)
(wait)
(fastrotate #f)
@end example



@chapter XaoS gallery

I plan to make a gallery of animations and position files on the XaoS home-page,
so please send any nice animations and images you created using XaoS
to @code{jh@@ucw.cz}.
@c ## chapter format ##
@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@comment  node-name,  next,      previous,  up
@node writehelp, xshl,format ,Top
@chapter How to write XaoS help files
XaoS help is stored in the file @code{help/xaos.hlp}. It is divided into parts,
each part being started by a @emph{keyword}. In the help file keywords are
written as @code{%keyword}

If you are writing documentation about some command in the XaoS function
registry, use the same keyword as the name of the command in order to make
context sensitive help work.






@c ## chapter writehelp ##
@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@comment  node-name,  next,      previous,  up
@node xshl, drivers,writehelp ,Top
@section xshl
@emph{Xshl} stands for @emph{XaoS simple hypertext language}. It
uses similar tags to HTML. It is simpler and more restrictive in order to
make it easy to parse using various scripts. In C code you can use the
library present in @code{src/util/xshl.c} to parse it.

The following tags are supported:

@table @strong
@item head
make headings (should be at the beginning of the page, at least)
@item emph
emphasize
@item tt
Use non proportional font
@item br
Break line
@item p
Next paragraph
@item dl
Definition list
@item dt
Definition tag (should be used only inside a definition list)
@item dd
Definition description (should be used only inside a definition list)
@item center
align to center
@item right
align to right
@item red
change color to red (should not be used in help files)
@item black
change color to black (should not be used in help files)
@item white
change color to white (should not be used in help files)
@item a name
link to other help page
@item tutor name
activate tutorial
@item notex
Ignore this in texinfo manuals
@end table

@c ## section xshl ##

@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@comment  node-name,  next,      previous,  up
@node drivers, menus,xshl ,Top

@chapter Driver specific documentation
XaoS is portable and works on many different platforms. Since not all platforms are
exactly the same, there are some differences between the behaviour of XaoS on
different platforms. Here is documentation about each specific port.



@c ## chapter drivers ##

@menu
* aa::			AA-lib --- high quality ascii art driver
* BeOS::		BeOS drivers
* DGA:: 		DGA driver
* dos::			DOS driver
* dX-fullscreen::	directX fullscreen driver
* dX-window::		directX windowed driver
* ggi::			GGI driver
* plan9::		plan9 driver
* SVGAlib::		SVGAlib driver
* win32::		Win32 driver
* X11:: 		X11 driver
@end menu

@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@comment  node-name,  next,      previous,  up
@node aa, BeOS , ,drivers

@section AA-lib driver

The AA driver is currently the most advanced and portable driver for XaoS.
It is based on AAlib---a high quality ASCII-art library developed by the AA-project.
(see @code{http://aa-project.sf.net})

It is a fully featured XaoS driver for text mode displays. It supports 256 colors
and the mouse where possible.

It also has some extended features available from the UI menu:

@table @strong
@item Attributes
AA-lib may use character attributes to improve image quality.
By default it uses normal, dim and bold characters where possible,
but you can also enable different attributes like reversed or bold font
characters. You may also enable usage of non ansii/reversed characters if
your device supports it.
@item Font
AA-lib uses a bitmap image of the font to prepare the approximation table
used for ASCII art rendering. This bitmap is expected to be same as the one used
by your device. AAlib performs detection where possible however some devices
(like UNIX text terminals or MDA) do not support this. AAlib has few font
images compiled in, so in this case you should try to use one of them to
achieve best results.
@item Inversion
Some devices use inverse video: use this to get correct results on such devices.
@item Dithering mode
Dithering is an way to get more exact color in approximations, by combining
more characters; but this method can produce ugly looking noise on certain images.
Use this menu to disable or tune it.
@item Palette options
By default AA driver uses the XaoS palette to render images, but it quite often
looks ugly on text displays. Here you can choose a special text palette instead. Note that with
filters enabled, the results may be rather ugly. This function is available from
the @emph{palette menu}.
@item Save text screen
The normal save function will generate a PNG image instead of nice
ASCII-art. To save ASCII art use this function instead. It supports many
text file formats like HTML, ANSI, more, etc... It will also ask you for
font and attributes(see above). It is available from the @emph{file
menu}.
@end table

The AA-lib driver also provides the full set of standard AA-lib's command line
options. You may use them to tune parameters like gamma correction, and so on.
See @code{xaos -help} or the AA-lib documentation for details.

The AA driver was written by Jan Hubicka, 1997.

@c ## section aa ##

@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@comment  node-name,  next,      previous,  up
@node BeOS, DGA , aa ,drivers

@section BeOS support

XaoS has pretty advanced support for BeOS R4. It works on both PowerPC and
Intel platforms, supports multithreading, the clipboard, file dragging,
has native look and feel and can work as an image translator from XaoS files
to images.

The first version of the BeOS driver was written by Jens Kilian and later
extended by Jan Hubicka.

@subsection Installation

You can start the installation script to do everything for you. If you want
something special, read this section.

In order for XaoS to work you need to keep the executable together with
its data files (@code{help}, @code{examples}, @code{catalogs} and the @code{tutorials} directory)

When first started, XaoS registers two new mime types called
@code{image/x-xaos-position} for XaoS Position Files and
@code{video/x-xaos-animation} for XaoS Animation Files,
registers icons for them and sets itself as default application.

@subsection Available display drivers

XaoS supports following drivers:

@table @strong
@item BeOS
Standard windowed driver using application server
@item DirectWindow
Driver done using Game Kit's direct window class
@item WindowScreen
Fullscreen driver.
@end table

By default, XaoS starts in windowed mode and uses the application server for output.
You could change the driver to DirectWindow to use direct access to video RAM.
Note that this mode is slower in most cases, and not supported by some videocards.

The BeOS driver by default chooses the most similar bitmap supported by XaoS
to achieve best and fastest results.
In the UI menu you can change this default choice to another one if you wish.
Also you can ask the BeOS and DirectWindow to resize to fullscreen mode.

XaoS also supports real fullscreen mode using the BWindowScreen API. To switch
XaoS to this driver, use the UI menu. If you want to use this mode by default,
use the @code{-driver WindowScreen} command line option.

This driver differs a lot from windowed ones. It use direct access to the video
card, allowing you to change video mode. Also, the 256 color mode
can access the palette, so it is not dithered like the windowed mode.
Because BeOS can't do GUI in fullscreen mode, XaoS uses its own toolkit.
I hope you will feel confortable in it.

@subsection XaoS as translator

You should be able to open XaoS files in graphics applications
such as ShowImage or ArtPaing. In Preferences you can find the DataTranslations
program, that can be used to set the size, type and DPI of the resulting image.
Also antialiasing can be enabled.

Note that @emph{translation can take a while}. So be patient and
wait for the result.

If the translator doesn't work, ensure that you have a link to the XaoS executable
in @code{/boot/beos/system/add-ons/Translators/}.

@c ## section BeOS ##

@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@comment  node-name,  next,      previous,  up
@node DGA, dos , BeOS ,drivers

@section DGA driver
This is the driver for DGA (Direct Graphics Architecture) extension used by
XFree86 X servers. It is pretty new so it could be buggy.

Bugs/limitations:

@table @strong
@item In 8bpp mode, XaoS has problems with the palette with certain window managers
I don't know why this happens. Just let me know what's wrong, or use another
window manager.
@item Banked modes are not supported.
I don't have any card to test this with, so it doesn't work in the current version.
@end table

DGA driver was written by Jan Hubicka, 1999.


@c ## section DGA ##

@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@comment  node-name,  next,      previous,  up
@node dos, dX-fullscreen , DGA ,drivers

@section DOS driver
This is a fully featured driver for DJGPP and allegro.
It supports many VGA modes, VESA 1.0---3.0, VBE/AF, S3 and some other cards.

The following problems may occur:

@table @strong
@item Some DPMI servers may cause problems
Some DPMI servers like the one from Novell/Dr/Open DOS are buggy. Use clean DOS
instead and XaoS will automatically start @code{cwsdpmi}.
Under Open Dr DOS use @code{dpmi off} at command line to disable it.
@item Higher resolutions don't work
If your videocard has enough memory for the selected resolution,
you most probably have an unsupported videocard.
Please use a VESA BIOS extension on this videocard. (See the note about VESA
at the end of this section.)
@item XaoS needs a coprocessor
I don't distribute a coprocessor library linked into XaoS because it is too slow for
a real-time zoomer. Coprocessor emulation will not help, because xaos works in protected mode.
@item XaoS needs mouse driver to be usable
@item XaoS works slowly in higher resolution
This could also be caused by Allegro's slow driver or your videocard's VESA BIOS.
You could try some other VESA BIOS extension instead.
Look at the @code{http://www.talula.demon.co.uk} for the FreeBE
project or Scitech Display Doctor package.
(See the note about VESA at the end of this section.)
@end table
@subsection VESA
VESA is a standard for using higher resolutions in DOS. Many videocards have
VESA support in the BIOS so you don't need any additional software, while others
need support from a special program. Also some VESA BIOS implementations are
buggy or suboptimal; there are 3 different versions, version 1.0 is many times
slower than 2.0, which has support for protected mode and linear framebuffers.
So if you have problems with higher resolutions, or some graphics modes are
not available (like 320x200 truecolor), you might try some software package
which emulates VESA.

The most famous VESA emulating program is Scitech Display Doctor. It has support
for many videocards and is quite reliable. It's disadvantage is that it is
shareware and works for only 30 days. You might also look on
@code{ftp.simtel.net}, where there are many VESA emulation packages such as
@code{s3vbe} or the new FreeBe project at
@code{http://www.talula.demon.co.uk}

DOS driver was written by Jan Hubicka, 1997.

@c ## section dos ##

@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@comment  node-name,  next,      previous,  up
@node dX-fullscreen, dX-window , dos ,drivers

@section DirectX fullscreen driver
This is da river for Windows 9x and NT. It is new since version 3.1 and
because of some oddities of Windows API and kludges in DirectX
it may be rather unstable. Please report all bugs. In case
of problems you could use the DOS version of XaoS instead.

This driver allows the Windows port of XaoS to run in full screen mode.
The driver supports 256, 65536 and 16777216 color modes (24bpp and 32bpp)
in all resolutions supported by DirectX.
You can change graphics mode by pressing the @code{=} key
(or by using the UI/Resize menu). If the selected mode is not supported,
the driver will restore the previous setting.

Use the @code{-mode WIDTHxHEIGHTxDEPTH} (like @code{-mode 640x480x16})
command line option to change graphics mode.

If you want to start XaoS in DirectX, use the @code{-driver dX-fullscreen}
option.

See the Win32 driver documentation for some more Windows
releated information.

DirectX driver was written by Jan Hubicka, Jan Olderdissen
and Pavel Tzekov, 1999.
@c ## section dX-fullscreen ##

@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@comment  node-name,  next,      previous,  up
@node dX-window, ggi , dX-fullscreen ,drivers
@c ## section DX-window ##

@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@comment  node-name,  next,      previous,  up
@node ggi, plan9, dX-window ,drivers

@section GGI driver

GGI stands for General Graphics Interface. Part of this project is to develop
libggi, a portable graphics library, and XaoS's GGI driver uses that.
It is experimental, since the API of libggi is not stabilized yet.
There are some problems with keyboard handling---the shift key doesn't work
yet.

Everything else might work well, but there are no guarantees. It is alpha quality
software.

GGI driver was written by Jan Hubicka, 1998.
@c ## section ggi ##

@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@comment  node-name,  next,      previous,  up
@node plan9, SVGAlib, ggi ,drivers

@section Plan9 driver

Plan9 is a very nice small operating system by the authors of Unix at Bell Labs.
It is very incompatible with other operating systems; even the C compiler and
header files are different, but XaoS should work well there (even on the
limited free demo installation without any POSIX compatibility stuff)

There are a few limitations: the file selector and image saving don't work.
You can save position files and then later render them on the other OS, or save
screenshots.

Plan9 terminals also don't provide any way to catch the arrow keys, so you
can't use them. Use the mouse to navigate in the menus. Also, getting the screen
resolution is impossible, so use @code{-pixelwidth} and @code{-pixelheight}
instead of @code{-screenwidth} and @code{-screenheight}.

By default XaoS changes the colormap. This will collide with other colorful
programs like Mortha. You can disable this behavior using
@code{-nopalette} switch, but this will slow down XaoS.

Plan9 driver was written by Jan Hubicka, 1997.
@c ## section plan9 ##

@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@comment  node-name,  next,      previous,  up
@node SVGAlib, win32, plan9 ,drivers

@section SVGAlib driver

This is a driver for Linux SVGAlib. I really like this driver, because
I much prefer full screen zooming instead of a small 320x320 window in X11.
It was one of the first drivers for XaoS and is fully featured.
The following problems can occur:

@table @strong
@item XaoS doesn't initialize graphics mode
when started under users other than root SVGAlib requires root privileges
to directly access the hardware. When you really want to start XaoS as a
normal user, enable the suid bit (@code{chmod +s}) at XaoS executable.
note that I take care to disable all security holes caused by this
bit so I believe it is safe.
@item Mouse doesn't work
@item Screen is blank at higher resolutions
Both this problems are probably caused by misconfiguration of
SVGAlib. Please configure it in @code{etc/vga/libvga.cong} or
@code{/usr/local/lib/libvga.conf}
GPM can also cause problems. Try to kill it before starting XaoS.
@item When I switch console I can't switch back
This is another typical SVGAlib bug. Try to hold @code{F} key longer than @code{alt}.
It helps on my computer. On older SVGAlib there was a famous ``enter bug'' that caused
a crash after pressing enter. Try to update to a newer release.
@end table

SVGAlib driver was written by Jan Hubicka, 1997.

@c ## section SVGAlib ##

@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@comment  node-name,  next,      previous,  up
@node win32, X11, SVGAlib ,drivers

@section Win32 driver

This is a driver for Windows 9x and NT. It is new since version 3.1 and
because of some oddities of Windows API it may be rather unstable.
Please report all bugs. In case of problems you could use the DOS version
of XaoS instead.

The driver should work in all bit depths, but 16 color mode is not natively
supported by the XaoS engine. XaoS internally works in 32k colors and
the result is converted to 16 colors by Windows. Because Windows
conversion routines are slow and ugly, the result is slow and ugly.
Please configure your display to another bit depth to ``solve''
this problem.

Use @code{-size WIDTHxHEIGHT} command line option to change the default
window size.

This driver also maps to native Windows look and feel. There is a small
problem with combo boxes in dialogs. They are expected to give you a choice
between a few strings. The keyboard controls (changing choice by arrow keys)
work, but mouse selection is broken. If you know how to solve this bug,
please let me know.

XaoS is a UNIX application and has many command line options.
Some features are not available from the GUI.
Because Windows applications can't have normal output,
most of the critical messages are displayed in message boxes, but
some longer messages are omitted. The most significant omission is the help
about command line options that you can find in @code{doc/cmdopts.txt}.

One thing that might be confusing is that animation rendering mode doesn't
display anything, but only renders images. Start the rendering,
and a message box will inform you that XaoS is entering the calculation
loop. Relax and wait for the message box signaling the end of the loop.

Note that XaoS also supports the DirectX API.

Win32 driver was written by Jan Hubicka, Jan Olderdissen and Pavel Tzekov, 1999.
@c ## section win32 ##

@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@comment  node-name,  next,      previous,  up
@node X11, , win32 ,drivers

@section X11 driver
This was the first driver done for XaoS. It supports many visuals, shared
colormaps and MitSHM extension.

Bugs/limitations:

@table @strong
@item XaoS makes some X servers too busy
Sometimes XaoS generates images faster than X can display them.
In this case XaoS responds poorly to the mouse, and other applications slow
down too. This happens especially often on old R4 servers. Use @code{-sync}
to avoid this problem. Note that @code{-sync} does @code{not} make all
communication with X asynchronous; it just adds one additional XSync call.
So the slowdown is not as large as you might expect.
@item Does not work on all visuals
This driver supports only 8bpp pseudocolor/grayscales, 15,16,24 and 32bpp truecolor, 1bpp and 8bpp staticolor visuals.
@item Palette rotating does not work for 8bpp pseudocolor w/o private palette
@end table

X11 driver was written by Jan Hubicka and Thomas Marsh, 1997.

@c ## section X11 ##

@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@comment  node-name,  next,      previous,  up
@node menus, authors,  drivers,Top

@appendix Menus, functions and command line parameters
All XaoS functions are referenced by a central function registry. The
scripting language, menus, dialogs and command line options are built
from this database. This section contains information about all functions
available in this registry.
@menu 
* root::	Root menu
* animroot::	Animation root menu
* plc::	Replay only commands

* linemenu::	Line drawing functions
* animf::	Animation functions
* time::	Timing functions
* file::	File
* edit::	Edit
* fractal::	Fractal
* calc::	Calculation
* mfilter::	Filters
* ui::	UI
* misc::	Misc
* helpmenu::	Help
* xtextpos::	Horizontal text position
* ytextpos::	Vertical text position
* mformula::	Formulae
* palettemenu::	Palette
@end menu 
@node root,  animroot,  ,  menus



@node animroot,  plc,  root,  menus



@appendixsec Animation root menu
This menu is displayed at the top of the screen when animation replay is active.
@menu 
* file::	File
* stopreplay::	Stop replay
* helpmenu::	Help
* ui::	UI
@end menu 
@node stopreplay,  ,  ,  animroot


@appendixsubsec Stop replay
Terminate animation replay.

@emph{Available as}: menu item



@node plc,  linemenu,  animroot,  menus


@appendixsec Replay only commands
Some commands, such as timing primitives or animation functions, are available
only in animation files.
@menu 
* linemenu::	Line drawing functions
* animf::	Animation functions
* time::	Timing functions
* load::	Include file
@end menu 
@node load,  ,  ,  plc




@appendixsubsec Include file
@defun load file 
@end defun

This function lets you include another file in your script. It works similarly
to @code{#include} in C or @code{load} in Scheme.
The file is searched for in the same directory as the current source file.

@emph{Available as}: command

@node linemenu,  animf,  plc,  menus



@appendixsec Line drawing functions
XaoS has support for drawing lines. These functions are available only in
animations and could be used to show some parts of fractals or draw simple
diagrams. See the tutorial ``Introduction to fractals''
for examples of this feature.

Lines can be drawn in @emph{screen} coordinates, where 0,0
is the top left corner and 1,1 is bottom right, @emph{scaled}
coordinates, which are similar, but scaled to keep 0,0---1,1 rectangular,
or @emph{Fractal} coordinates, to draw a line at an exact position
on the screen.

The color of the line should be specified by the @code{color} command.
You might draw an arbitrary number of lines and, later, morph them. Each line is
identified by a unique numeric key; the current key can be set using @code{linekey}.
Commands for changing lines operate on the line with the current key.
(Lines drawn in sequence have consecutive numbers.)

For example:


@example
(color 'red)
(line 'scaled 0.3 0.5 0.7 0.5)
(line 'scaled 0.3 0.5 0.7 0.5)
(line 'scaled 0.3 0.5 0.3 0.5)
(line 'scaled 0.7 0.5 0.7 0.5)
(linekey 0)
(morphline 'scaled 0.3 0.3 0.7 0.3)
(morphline 'scaled 0.3 0.7 0.7 0.7)
(morphline 'scaled 0.3 0.3 0.3 0.7)
(morphline 'scaled 0.7 0.3 0.7 0.7)
(usleep 1000000)
@end example


Creates line morphing to rectangle.




@defun line keyword complex complex 
@end defun

Draw line between two points.
@code{keyword} specifies type of coordinates and should be one of the
following: @code{`fractal}, @code{`screen} or @code{`scaled}.
This function also increases the line key.

@emph{Available as}: command





@defun morphline keyword complex complex 
@end defun

Morph current line to given coordinates.
@code{keyword} specifies type of coordinates and should be one of the
following: @code{`fractal}, @code{`screen} or @code{`scaled}.
The line will start moving at the next timing command, and reach the
final position before the end of it.
This function also increases the line key.

@emph{Available as}: command





@defun morphlastline keyword complex complex 
@end defun

This function has the same functionality as morphline, but it doesn't
increase the line key, and touches the line with the previous key. This is useful when
you want to move a just-drawn line---you don't need to set linekey back.

@emph{Available as}: command



@defun linekey integer 
@end defun

Set current line key.

@emph{Available as}: command



@defun clearline 
@end defun

Clear current line. This function also increases the line key.

@emph{Available as}: command

@defun clearlines 
@end defun

Clear all displayed lines. Lines can also be cleared using the
@code{clearscreen} or @code{display} commands available from the Misc menu. @xref{misc}.

@emph{Available as}: command

@node animf,  time,  linemenu,  menus



@appendixsec Animation functions
These functions are used to animate fractal state---to zoom, unzoom and morph
various parameters. They should be used only in animation files.
Animations are usually performed for a time selected by an immediately following
timing function. @xref{time}.
For example:


@example
(view 0 0 1 1)
(morphview 0 0 2 2)
(usleep 5000000)
@end example


Will do a 5 second long unzooming animation.
@menu 
* animateview::	Animate view
* smoothmorph::	Smooth morphing
* morphview::	Morph view
* morphjulia::	Morph julia
* moveview::	Move view
* morphangle::	Morph angle
* zoom::	Zooming functions
@end menu 
@node animateview,  smoothmorph,  ,  animf


@appendixsubsec Animate view
@defun animateview float float float float 
@end defun

This function is almost identical to function @code{view}. @xref{uiview}.
It expects that the view will be changed only slightly, so recalculation is done
with @code{ANIMATE} priority. This means that dynamic resolution is used by
default.

Viewport is selected by the center and two radiuses (real and imaginary). See
@code{view} for more information.

@emph{Available as}: command

@node smoothmorph,  morphview,  animateview,  animf


@appendixsubsec Smooth Morphing
@defun morphview keystring starttime endtime 
@end defun
This function lets you smoothly start and stop morphing. Specify
starttime and stoptime as nonzero, and morphing will speed up and slow down for
that number of usecs.

The keystring is used to select what morphing you want to control. It is one of
the following:
@table @strong
@item 'view
control morphview
@item 'angle
control morphangle
@item 'julia
control morphjulia
@item 'line
control morphline
@end table
@node morphview,  morphjulia,  smoothmorph,  animf


@appendixsubsec Morph view
@defun morphview float float float float 
@end defun
For the time selected by the next @code{usleep} or other timing function, the viewpoint is smoothly morphed from
the current one to that selected by @code{morphview}.

Viewport is selected by the center and two radiuses (real and imaginary). See
@code{view} for more information.

This function can easily be used for creating zooming/unzooming animations using position files.
This is an example position file generated by XaoS:


@example
(initstate)
(defaultpalette 0)
(formula 'mandel)
(view -1.64128273713 -5.50393226816E-05 9.69332308848E-08
9.69332308834E-08)
@end example


By replacing the @code{view} command with @code{morphview} and
adding @code{usleep} you can create a zooming animation:


@example
(initstate)
(defaultpalette 0)
(formula 'mandel)
(morphview -1.64128273713 -5.50393226816E-05 9.69332308848E-08
9.69332308834E-08)
(usleep 10000000)
@end example




@emph{Available as}: command

@node morphjulia,  moveview,  morphview,  animf


@appendixsubsec Morph Julia
@defun morphjulia complex 
@end defun
For the time selected by the next @code{usleep} or other timing function, the Julia seed
is smoothly interpolated from the current one to that selected by @code{morphjulia}. By default this will
cause recalculation of the whole screen.
To avoid this, use fast Julia mode. @xref{fastjulia}.

A simple animation morphing Julia seed in the X axis:


@example
(initstate)
(fastjulia #t)
(juliaseed -2 0)
(morphjulia 2 0)
(usleep 2000000)
@end example



@emph{Available as}: command

@node moveview,  morphangle,  morphjulia,  animf


@appendixsubsec Move view
@defun moveview complex 
@end defun
Smoothly move the image center to another position.

@emph{Available as}: command

@node morphangle,  zoom,  moveview,  animf


@appendixsubsec Morph angle
@defun morphangle float 
@end defun
Smoothly rotate the image to another angle. By default rotation causes
recalculation of the whole screen. To avoid this you need to enable
fast rotate mode. @xref{rotate}. Don't forget to disable it later, since
it slows down other animations.


A simple ``rotozooming'' animation:


@example
(initstate)
(fastrotate #t)
(morphview -1.64128273713 -5.50393226816E-05 9.69332308848E-08
9.69332308834E-08)
(morphangle 300)
(usleep 10000000)
(wait)
(fastrotate #f)
@end example


@emph{Available as}: command

@node zoom,  ,  morphangle,  animf


@appendixsubsec Zooming functions

The functions for zooming/unzooming were created mainly for recording
animations. In manually created animation files, it is easier to use
@code{morphview}. @xref{morphview}.

@defun zoomcenter complex 
@end defun
This function sets the center to zoom in on. The center is given as a position
in fractal coordinates.

@emph{Available as}: command
@defun zoom 
@end defun
Start zooming to the area specified by @code{zoomcenter}.

The speed of zooming should be controlled by the function @code{speed}
or in a more exact way by @code{maxstep} and @code{speedup}.

@defun unzoom 
@end defun

Start unzooming from the area specified by @code{zoomcenter}.

@emph{Available as}: command
@defun stop 
@end defun
Stop zooming or unzooming.

@emph{Available as}: command

@node time,  file,  animf,  menus



@appendixsec Timing functions
Timing functions are used to control the animation replay daemon. It can wait
for a given time, or wait until calculation is complete. The animation functions
are controlled by such waiting; animations that are running while delays start
keep running through the delay.
@menu 
* usleep::	Usleep
* textsleep::	Wait for text
* wait::	Wait for complete image
@end menu 
@node usleep,  textsleep,  ,  time


@appendixsubsec Usleep
@defun usleep integer 
@end defun

This function waits for a given amount of time (in usec) before processing
the next command. The screen is recalculated and displayed at the beginning of
usleep if necessary necessary. The remaining time is spent in waiting or
performing animation.

@emph{Available as}: command

@node textsleep,  wait,  usleep,  time


@appendixsubsec Wait for text
@defun textsleep 
@end defun


This function's behavior is very similar to @code{usleep},
but the time is calculated from the number of letters currently displayed
onscreen. If you want to wait just long enough for the user to read the subtitle,
use this function. The user can alter the replay speed as desired using
@code{letterspersec}. @xref{letterspersec}. This value can be changed during
replay with the arrow keys.

@emph{Available as}: command

@node wait,  ,  textsleep,  time


@appendixsubsec Wait for complete image
@defun wait 
@end defun

Wait until the image is complete. You should always use this function after
zooming or unzooming when dynamic resolution is in use. This ensures that
the image calculation will be complete so the user can see the result before
the animation continues. It may also be useful in combination with filters like
motion blur. @xref{blur}.

This function deadlocks if used with animation functions; don't
do that.

@emph{Available as}: command

@node file,  edit,  time,  menus



@appendixsec File
@menu 
* loadpos::	Load
* savepos::	Save
* record::	Record
* play::	Replay
* saveimg::	Save image
* loadexample::	Load random example
* savecfg::	Save configuration
* quit::	Quit
@end menu 
@node loadpos,  savepos,  ,  file


@appendixsubsec Load XaoS position file

Load a XaoS position file (@code{*.xpf}).
See the format description for more information.

@emph{Available as}: menu item, command line option

@node savepos,  record,  loadpos,  file


@appendixsubsec Save XaoS position file
@defun savepos file 
@end defun

Save current state to a XaoS position file (@code{*.xpf}). This file is
human-readable, and can easily be improved by hand after saving, or used as
a base for animations.
See the format description for more information.

@emph{Available as}: menu item, command line option, command

@node record,  play,  savepos,  file


@appendixsubsec Record animation
@defun record bool [ file ] 
@end defun


e
Toggle recording to a XaoS animation file (@code{*.xaf}). This file is
human-readable, and can easily be improved by hand after recording.
See the format description for more information.

From the scripting language, @code{(record #t)} enables recording, and
@code{(record #f)} disables it.

@emph{Available as}: menu item, command line option, command

@node play,  saveimg,  record,  file


@appendixsubsec Replay animation

Replay a XaoS animation file (@code{.xaf}).

@emph{Available as}: menu item, command line option

@node saveimg,  loadexample,  play,  file


@appendixsubsec Save image
@defun saveimg file 
@end defun

Save current state to an image file. This file is in @code{.png} (portable
network graphics) format, which can be read by many applications varying from
graphics programs all the way to Web browsers.

This function needs an external library called @code{libpng}. If the library
wasn't available during compilation, this function is unavailable too.
Please see @code{INSTALL} for more information about obtaining libpng
and recompiling XaoS.

@emph{Available as}: menu item, command line option, command

@node loadexample,  savecfg,  saveimg,  file


@appendixsubsec Load random example
@defun loadexample 
@end defun

Choose random @code{.xpf} file from the @code{examples} directory and
load it.
You might use it as the starting point for next exploration.

@emph{Available as}: menu item, command line option, command

@node savecfg,  quit,  loadexample,  file


@appendixsubsec Save configuration
@defun savecfg 
@end defun

Save current configuration to @code{~/.xaosrc} (under Unix) or @code{xaos.cfg}
(under DOS and Windows). XaoS automatically reloads the configuration from this
file when it starts.

@emph{Available as}: menu item, command line option, command

@node quit,  ,  savecfg, file


@appendixsubsec Quit
@defun quit 
@end defun

Quit XaoS.

@emph{Available as}: menu item, command line option, command

@node edit,  fractal,  file,  menus


@appendixsec Edit
A fairly ordinary Edit menu.
@menu 
* undo::	Undo
* redo::	Redo
* copy::	Copy
* paste::	Paste
@end menu 
@node undo,  redo,  ,  edit


@appendixsubsec Undo
Undo last operation. `Last operation' is quite hard to define in
XaoS (where changes are continuous), so it might be surprising.
I hope it will do what you want.

@emph{Available as}: menu item
@node redo,  copy,  undo,  edit


@appendixsubsec Redo
Redo last undone operation. See undo. @xref{undo}.

@emph{Available as}: menu item
@node copy,  paste,  redo,  edit


@appendixsubsec Copy
Copy fractal to clipboard. This is a platform-dependent operation that may
not have an analogue on your platform (e.g. there is no concept of a clipboard
under aalib).

@emph{Available as}: menu item
@node paste,  ,  copy,  edit


@appendixsubsec Paste
Paste fractal from clipboard. This is a platform-dependent operation that may
not have an analogue on your platform (e.g. there is no concept of a clipboard
under aalib).

@emph{Available as}: menu item

@node fractal,  calc,  edit,  menus


@appendixsec Fractal
This menu contains all functions related to fractal parameters and display;
you can change things like the formula used, coloring modes, seeds and much
else.

@menu 
* formula::	Formula
* mformula::	formulae
* incoloring::	Incoloring mode
* outcoloring::	Outcoloring mode
* plane::	Plane
* palettemenu::	Palette
* uimandelbrot::	Mandelbrot mode
* uiperturbation::	Perturbation
* uiview::	View
* initstate::	Reset to defaults
* tcolor::	True-color coloring modes
@end menu 
@node formula,  uimandelbrot,  ,  fractal


@appendixsubsec Formula
@defun formula keyword 
@end defun

Set the current fractal formula. @code{keyword} should be one of the
following:
@table @strong
@item 'mandel
Standard Mandelbrot set. @xref{mandel}.
@item 'mandel3
Mandelbrot set, power 3. @xref{mandel3}.
@item 'mandel4
Mandelbrot set, power 4.
@item 'mandel5
Mandelbrot set, power 5.
@item 'mandel6
Mandelbrot set, power 6.
@item 'newton
Newton's approximation method. @xref{newton}.
@item 'barnsley
First Barnsley's formula. @xref{barnsley}.
@item 'octo
Fractint's octo. @xref{octal}.
@item 'phoenix
Phoenix. @xref{phoenix}.
@item 'magnet
Magnet. @xref{magnet}.
@end table

@emph{Available as}: command

@node uimandelbrot,  uiperturbation,  formula,  fractal


@appendixsubsec Mandelbrot/Julia mode

Most fractals rendered by XaoS can be represented as Mandelbrot sets or Julias.
Each point in the Mandelbrot set has its own Julia set. To learn more about
this correspondence, see the tutorial on the Julia set.

This function switches between Mandelbrot and Julia representations. When
switching to Julia, you need to set the seed---a point selected from the
Mandelbrot set.

If you run this function from the menu, you are prompted for the Julia seed
as a number. Often, this can be clumsy, and it would be easier to specify a
point with the mouse pointer. If you hit the @code{M} key instead of
using the menu, the current mouse position is used.

Good seedpoints lie at the boundaries of the Mandelbrot set; other seeds
usually generate quite a boring fractal. You can also explore various seeds
at high speed using the Fast Julia mode. @xref{fastjulia}.

Not all fractals have Julias, but XaoS can generate fake Julia sets for
those that do not, which use some Julia-like modification of the formula;
so this function is currently usable for all fractal types.

@emph{Available as}: menu item
@defun julia bool 
@end defun

This function is used to enable/disable julia mode in animation files.

@emph{Available as}: command line option, command
@defun juliaseed complex 
@end defun

Select the current julia seed.

@emph{Available as}: command line option, command

@node uiperturbation,  uiview,  uimandelbrot,  fractal


@appendixsubsec Perturbation

Perturbation is a simple trick which changes the point at which orbits start.
Traditionally zero is used, but other values can generate interesting
results too.

On enabling this function from the menu, you will be asked for a complex
number specifying the perturbation. It is a toggle; selecting it again
resets the perturbation to zero without prompting.

It can be used to specify a complex number representing a point on the screen.
If you hit the @code{B} key instead of using the menu, the current mouse
position is used. This too is a toggle, so @code{B} again will disable
perturbation by setting it to zero.

This function only has an effect for certain formulae (like the
Mandelbrot set</a>) and only then in <a uimandelbrot>Mandelbrot mode. @xref{mandel}.

@emph{Available as}: menu item
@defun perturbation complex 
@end defun

This is the scripting-language variation of the perturbation function. Instead
of toggling, you always specify the perturbation to use. Use 0 0 to disable
perturbation.

@emph{Available as}: command line option, command

@node bailout,  fastjulia,  maxiter,  calc


@appendixsubsec Bailout

Bailout is the value which is checked for each point of
the orbit if the point is far enough
from the complex zero point in the current iteration.
If the point is far enough, then the iteration immediately
stops and the starting point on the screen will be
painted with a given colour, depending on the fractal
type and many other settings.

For the Mandelbrot set
this value is 4. Other fractal types usually
have the same bailout value. For most fractals many bailout values
give more or less similar output. E.g., for the second order
Mandelbrot set one can prove that the sequence |z| (z:=z^2+c) tends to
infinity if and only if |z|>2 for some element z of this sequence.
In XaoS program, Bailout value is the square of this 2, i.e. you can change this
to any value greater than 2 for similar results.

Other fractal types may use other bailout values. The default
is 4 for each types.

@emph{Available as}: menu item, command line option, command
@defun bailout float 
@end defun


@node uiview,  initstate,  uiperturbation,  fractal


@appendixsubsec View

Set your current viewpoint in the fractal. This function is useful when you have
found some interesting coordinates somewhere (on a web page, perhaps) and you
want to see that position in XaoS.

In the dialog you will be asked for the @emph{center}, @emph{radius}
and @emph{angle} of the image.

The center specifies the point which is displayed at the center of the screen.
The radius is the radius of a circle around this point; XaoS will size the image
so that this circle only just fits on the screen. The angle gives the rotation of
the image in degrees.

People specify fractal coordinates in many ways. Some people use the coordinates
of the upper-left and lower-right visible points, specifying the coordinates as four
numbers @math{x1}, @math{y1}, @math{x2}, @math{y2}.
To set the same viewpoint in XaoS, set the real portion of the center to
@math{(x1+x2)/2}, the imaginary part of center to @math{(y1+y2)/2}, and
the radius to the greater of @math{x2-x1} and @math{y2-y1}.

Other programs use a zoom factor instead of a radius. For these, you can set the
radius to @math{2/zoom}.

@emph{Available as}: menu item
@defun view float float float float 
@end defun

This function is used to set the visible area of fractal in animation files.
It doesn't let let you specify the angle, (for that, see the separate function
@code{angle}), but lets you specify an ellipse instead of a circle. You can
specify both a real and an imaginary radius, so you have better control over the
area that will be visible. XaoS will size the image so that the ellipse only just
fits on the screen.

@emph{Available as}: command line option, command
@defun angle float 
@end defun

Set the rotation angle in degrees. By default this causes recalculation of the
screen. You can enable the fast rotation mode, which lets you
rotate the screen without recalculation; but it slows down other things, so
don't forget to disable it later.

@emph{Available as}: command line option, command

@node initstate,  plane,  uiview,  fractal


@appendixsubsec Reset to defaults
@defun initstate 
@end defun

This function resets most of XaoS' values to their defaults. It is useful when
you get lost and want to start from the beginning. It should also be used
as the first command of every animation file, to ensure that the file is always
played with the same settings in effect.

@emph{Available as}: menu item, command line option, command

@node plane,  incoloring,  initstate,  fractal


@appendixsubsec Plane
@defun plane integer 
@end defun

All fractals displayed by XaoS are functions with a complex parameter.
They can be be displayed in the normal complex plane where the @code{x}
coordinate is the real part of the number and the @code{y} is imaginary;
but they can also be displayed differently:
@table @strong
@item @math{mu}
Normal complex plane (default)
@item @math{1/mu}
Inversion---infinity is at 0 and
0 is at infinity.
@item @math{1/(mu+0.25)}
Similar to inversion, but moves
the center outside the Mandelbrot set,
so it looks parabolic.
@item @math{lambda plane}, @math{1/lambda}, @math{1/lambda-1}
Lambda plane and its inversion, and with a different center.
@item @math{1/(mu-1.40115)}
A very interesting mode for the
Mandelbrot set, this makes small
things large, for easier browsing
of the set's details.
@end table
The tutorial about planes has some examples.



In the scripting language, the planes are numbered as follows:

@table @strong
@item 0
@math{mu}
@item 1
@math{1/mu}
@item 2
@math{1/(mu+0.25)}
@item 3
@math{lambda}
@item 4
@math{1/lambda}
@item 5
@math{1/(lambda-1)}
@item 6
@math{1/(mu-1.40115)}
@end table

@emph{Available as}: command line option, command

@node incoloring,  outcoloring,  plane,  fractal


@appendixsubsec Inside coloring mode
@defun incoloring integer 
@end defun

Areas inside the set are usually filled in black, but this is only a convention;
you could color them in differently to make the fractal look more interesting.
The only method available to make areas inside the set visible is to display
the value of the latest orbit as the value of each pixel.

The tutorial on incoloring has more information and
examples.

XaoS has many different ways to show that value. The cryptic names of the modes
are mathematical formulae, where @emph{real} means the real part of the
latest orbit, and @emph{imag} means the imaginary part. @emph{zmag}
uses the magnitude of the value. The @emph{Decomposition-like} method uses
the angle of the orbit. Also, truecolor incoloring modes are available, that
display one value in each of the red, blue and green color planes (or, for some
modes, in each of the hue, saturation and value planes).

In the scripting language, the incoloring mode is specified by one of the
following integers:

@table @strong
@item 0
@math{0} (default)
@item 1
@math{zmag}
@item 2
Decomposition-like
@item 3
@math{real/imag}
@item 4
@math{abs(abs(c)-abs(r))}
@item 5
@math{cos(mag)}
@item 6
@math{mag*cos(real^2)}
@item 7
@math{sin(real^2-imag^2)}
@item 8
@math{atan(real*imag*creal*cimag)}
@item 9
squares
@item 10
Truecolor. To set exact parameters for truecolor coloring use the
@code{tcolor} command.
@end table

@emph{Available as}: command line option, command

@node outcoloring,  tcolor,  incoloring,  fractal


@appendixsubsec Outside coloring mode
@defun outcoloring integer 
@end defun

Outcoloring modes are similar to incoloring modes, but indicate
how to display the areas outside the set instead. As with incoloring modes, the
value of the latest orbit can be used to determine the color of each pixel, but the
default is to use the number of iterations needed for the value at that point to become
recognisably divergent as the color.

The tutorial on outcoloring has more information and
examples.

The cryptic names of the modes are mathematical formulae, where @emph{iter}
means the number of iterations required for the value to become recognisably divergent,
@emph{real} means the real part of the latest orbit, and @emph{imag}
means the imaginary part. @emph{binary decomposition} uses a different color
when the imaginary part of the orbit is lower than zero, and @emph{smooth}
attempts to remove stripes and discontinuities. Also, truecolor outcoloring
modes are available, that display one value in each of the red, blue and green color planes
(or, for some modes, in each of the hue, saturation and value planes).

In the scripting language, the outcoloring mode is specified by one of the following
integers:

@table @strong
@item 0
@math{iter} (default)
@item 1
@math{iter+real}
@item 2
@math{iter+imag}
@item 3
@math{iter+real/imag}
@item 4
@math{iter+real+imag+real/imag}
@item 5
binary decomposition
@item 6
biomorphs
@item 7
potential
@item 8
color decomposition
@item 9
smooth
@item 10
True-color outcoloring mode. To set exact parameters for truecolor coloring use @code{outtcoloring}. @xref{tcolor}.
@end table

@emph{Available as}: command line option, command

@node tcolor,  ,  outcoloring,  fractal


@appendixsubsec Truecolor coloring mode
@defun intcoloring integer 
@end defun
@defun outtcoloring integer 
@end defun

Truecolor coloring modes are similar to incolor and <a
outcoloring>outcolor</a> coloring modes; but instead of using a palette,
they directly calculate the red, green and blue components of the color.
This lets you display more parameters at once, and produces interesting
and often attractive results. On 8bpp displays you need to enable the
palette emulator filter first to see anything, amd the quality
won't be so good, as far fewer colors are available per parameter.

The tutorial on truecolor coloring modes has more
information and examples.

The cryptic names of the modes are always three mathematical formulae (one for
each color component), where @emph{real} means the real part of the latest
orbit, and @emph{imag} means the imaginary part.

To enable inside/outside truecolor coloring mode in the scripting language,
set @code{incoloring}/@code{outcoloring} value to 10 (truecolor coloring
mode) before (or after) calling @code{intcoloring} or @code{outtcoloring}.

In the scripting language, the coloring mode is specified by one of the following
integers:

@table @strong
@item 0
black
@item 1
@math{re*im} @math{sin(re^2)} angle
@item 2
@math{sin(re)} @math{sin(im)} @math{sin(square)}
@item 3
hsv
@item 4
hsv2
@item 5
@math{cos(re^c)} @math{cos(im^2)} @math{cos(square)}
@item 6
@math{abs(re^2)} @math{abs(im^2)} @math{abs(square)}
@item 7
@math{re*im} @math{re*re} @math{im*im}
@item 8
@math{abs(im*cim)} @math{abs(re*cre)} @math{abs(re*cim)}
@item 9
@math{abs(re*im-csqr)} @math{abs(re^2-csqr)} @math{abs(im^2-csqr)}
@end table

@emph{Available as}: command line option, command

@node calc,  mfilter,  fractal,  menus



@appendixsec Calculation
This menu contains functions that control calculation parameters such as
the maximum iteration count and periodicity checking.
@menu 
* range::	Solid guessing
* dynamic::	Dynamic resolution
* periodicity::	Periodicity checking
* maxiter::	Iterations
* bailout::	Bailout
* fastjulia::	Fast Julia mode
* dynamic::	Dynamic resolution
* rotate::	Rotation
@end menu 
@node range,  periodicity,  ,  calc


@appendixsubsec Solid guessing range
@defun range integer 
@end defun

XaoS has a solid guessing optimization: if all corners of a rectangle have
the same color, it assumes that the whole rectangle is a solid colored block,
and doesn't calculate points inside the rectangle. This optimization saves
lots of calculation, but sometimes introduces errors. This value alters the
maximum size of the rectangle that can be guessed at one time. The default
value is 3; use 0 to disable the optimization.

@emph{Available as}: command line option, command

@node periodicity,  maxiter,  range,  calc


@appendixsubsec Periodicity checking
@defun periodicity bool 
@end defun

Periodicity checking is one way to speed up the calculation. Areas inside the
set always need @code{maxiter} iterations to determine that
the point is probably inside the set (while it is rare for areas outside to
need anywhere near that much). Often the orbital trajectory falls into a
periodic, repeating cycle; if that can be detected, the calculation can be
stopped early, as there's no way that the orbit can ever leave the cycle
again (hence it cannot diverge, hence the point must be inside the set).

Implementating this method efficiently is quite problematic. It slows down
the cases where cycles are not found, because cycle-checking is quite hard work
and has to take place for all points, even those that don't become cyclic.
Because of the inexactness of floating-point calculations, the cycles are
never exact, so you need to use an error value. Higher error values mean that
cycles will be detected sooner, while lower error values increase the
exactness of the calculation. Higher values can introduce serious errors,
especially at the front of the Mandelbrot set. XaoS detects this automatically
and corrects for it in most cases, but sometimes it might be wrong. Also,
other optimizations in XaoS (such as boundary tracing) don't give this method
much of a chance to run, since areas inside the set are usually not
calculated at all.

That's why the advantages of this optimization are questionable. You should
probably experiment with enabling and disabling it. Sometimes XaoS is faster
with this enabled, sometimes when disabled. Also, this method works only
when incoloring methods are disabled, and only for some
fractal types (some fractal types, e.g. newton, don't have any concept of
an area `inside the set' at all.)

The tutorial chapter ``Escape time fractals'' has
more information on fractal calculation in XaoS, and there is a lengthy
section in the hacker's manual (@code{xaosdev.texinfo}) devoted to the
subject.

@emph{Available as}: menu item, command line option, command

@node maxiter,  bailout,  periodicity,  calc


@appendixsubsec Iterations
@defun maxiter integer 
@end defun

When the fractal set is calculated, a orbital trajectory is examined for each
point. If the orbit diverges to infinity, the point is outside the set.
Otherwise, the point is inside the set. For exact calculations, you need to
know the entire orbital trajectory, which is infinitely long for areas inside
the set, so fractals cannot be calculated exactly. By default, XaoS calculates
at most 170 positions (iterations) and then gives up; if the point is still
inside the bail-out value, it guesses that the point is inside the set.

When zoomed into a detailed area, especially one close to the set boundary,
this value could become too low, and the fractal will become boring.
You might try increasing this value if you want to get the image interesting
again; but this necessarily slows down the calculation at the same time.

The tutorial chapter ``Escape time fractals'' has
more information on fractal calculation in XaoS, and there is a lengthy
section in the hacker's manual (@code{xaosdev.texinfo}) devoted to the
subject.

@emph{Available as}: menu item, command line option, command

@node fastjulia,  dynamic,  bailout,  calc


@appendixsubsec Fast Julia mode
@defun fastjulia bool 
@end defun

By default, changing the seed for the Julia set requires recalculation of the
image (which is quite slow). It's a nice effect to change the seed smoothly and
show the Julia set morphing as the seed changes. XaoS has a special algorithm
which can calculate such morphings in realtime. It is very inexact, but it is
good enough for a fast preview.

If you want to select a good seedpoint, enable fast Julia mode and find a
nice place by dragging with the first mouse button depressed; then change to
the Julia mode to see the exact image.

@emph{Available as}: menu item, command line option, command

@node dynamic,  rotate,  fastjulia,  calc



@appendixsec Dynamic resolution
@defun fastmode keyword 
@end defun

XaoS performs many optimizations, but fairly often this is not enough. In order
to keep a high framerate, XaoS automatically lowers the resolution of the image,
increasing it when there is time for more calculation. This feature is enabled by
default when animating, but you might also like to enable it for new images
(which makes the image `come into focus' when it is recalculated from scratch for
whatever reason), or disable it completely if you don't like it.

In the scripting languge, the keyword should be one of the following:
@table @strong
@item @code{'never}
Disable dynamic resolution
@item @code{'animate}
Use only for animations (default)
@item @code{'new}
Use also for new images
@end table
@node rotate,  ,  dynamic,  calc



@appendixsec Image rotation

XaoS has support for rotation of the image to any angle. By default, changing
the angle requires recalculation of the whole screen, but when
@emph{fast rotation mode} is enabled, the angle can be changed smoothly.
In this mode XaoS calculates a larger non-rotated image and rotates it when
needed, so it increases memory requirements and slows XaoS down; hence, it
should be disabled when rotation is not being used.

The user interface provides two rotation modes---@emph{rotate by
mouse} which allows the angle to be changed by dragging with the first
mouse button depressed, and @emph{continuous rotation mode}, where the image
is rotated clockwise continuously, and the arrow keys can be used to change
the rotiation speed.
@defun fastrotate bool 
@end defun

This function is used to enable and disable fast rotation mode.
@emph{Available as}: command line option, command
@appendixsubsec Automatic rotation
@defun autorotate bool 
@end defun

Use this function to enable continuous rotation. In the scripting language you
can also use @code{morphangle} to get an outwardly similar
but more controllable effect.
@defun rotationspeed float 
@end defun

Specify the speed of continuous rotation, in degrees per second.
Negative values are allowed and rotate anticlockwise.

@emph{Available as}: menu item, command line option, command



@node mfilter,  ui,  calc,  menus



@appendixsec Filters
Filters are a post-calculation effect applied to the resulting image. They
can do things like motion blurring, edge detection, emulation of palettes
or truecolor on displays that can't handle them, and such things. There is
a tutorial chapter about them.

@menu 
* filter::	Filter command
* edge::	Edge detection
* edge2::	Edge detection2
* starfield::	Starfield
* stereogram::	Random dot stereogram
* interlace::	Interlace filter
* blur::	Motion blur
* emboss::	Emboss
* palettef::	Palette emulator
* anti::	Antialiasing
* truecolor::	Truecolor emulator
@end menu 
@node filter,  edge,  ,  mfilter


@appendixsubsec Filter command
@defun filter keyword bool 
@end defun

This command is used to enable or disable filters. @xref{mfilter}.
The @emph{keyword} specifies the filter to change, and should be one of
the following:

@table @strong
@item @code{'edge}
Edge detection
@item @code{'edge2}
Edge detection2
@item @code{'starfield}
Starfield
@item @code{'stereogram}
Random dot stereogram
@item @code{'interlace}
Interlace filter
@item @code{'blur}
Motion blur
@item @code{'emboss}
Emboss
@item @code{'palette}
Palette emulator
@item @code{'anti}
Antialiasing
@item @code{'truecolor}
Truecolor
@end table

@emph{Available as}: command
@node edge,  edge2,  filter,  mfilter


@appendixsubsec Edge detection

This filter is a standard edge detection algorithm; solid areas are filled
in black. Some fractals look very interesting with this filter (and some
areas of some fractals just look like noise). This version of the filter produces
relatively wide lines, so is useful at higher resolutions. The filter
edge detection2 makes thinner lines, for the low resolution modes.

@emph{Available as}: menu item, command line option

@node edge2,  starfield,  edge,  mfilter


@appendixsubsec Edge detection2

This filter is a standard edge detection algorithm; solid areas are filled
in black. Some fractals look very interesting with this filter (and some
areas of some fractals just look like noise). This version of the filter produces
relatively tight lines, so is useful at lower resolutions. The filter
edge detection makes thinner lines, for the high resolution modes.

@emph{Available as}: menu item, command line option

@node starfield,  stereogram,  edge2,  mfilter


@appendixsubsec Starfield

The starfield filter generates random stars whose density depends on the
iteration count. Choose your favorite spiral fractal and enable this filter
to get a Grand Design spiral galaxy :)

@emph{Available as}: menu item, command line option

@node stereogram,  interlace,  starfield,  mfilter


@appendixsubsec Random dot stereogram

Fractal images are good as a base for random dot stereograms. In
case you don't know what these are, please point your browser to
Google or another search engine and find some articles about such
images, because learning to read such images takes some effort. They
make it possible to generate three dimensional images on a normal monitor
without any additional hardware, by exploiting bugs in the human brain
(although you need two working eyes, and some people never learn to
see them; they can simply ignore this feature).

XaoS is able to generate these images in animations, so you may use
all normal XaoS functions (except palette changing and palette rotation,
which makes no sense applied to a stereogram). To make the animation yet
more exciting, XaoS emulates ``falling'' into the set; while you zoom in,
your distance from the set drops and drops---but you never hit it; when the
set reaches the level of your monitor, the distance is changed again so
you are far away.

To make this work right, XaoS needs to know the @emph{exact size of your
monitor}. Because most platforms have no way to determine this, you need to
use @emph{command line options} to tune it. If it's not set or is wrong,
the stereograms will probably be impossible to see (if your monitor is too
big or resolution too low), or the images will seem to be shallow (if your
monitor is too small or resolution too high).

By default XaoS expects my 15" monitor (29.0cm x 21.5 cm). Another
cause of problems is the virtual screen supported by some windowed
environments (like some X servers) that makes a program think that the
resolution is higher than it actually is, and you see only part of
this extra-large screen.

The worst thing you could possibly do is to run full-screen XaoS in some
graphical windowing system (OS/2 on top of Windows or Wine on top of Linux,
perhaps) where XaoS can't tell the real size of its window at all. In such
cases, it's normally better (not to mention faster) to run XaoS natively,
rather than under such an emulation layer.

The following command line options are provided to specify sizes:

@table @strong
@item @code{-screenwidth}, @code{-screenheight}
Lets you specify the size of your screen in centimeters. Note that
you need to specify the size of the visible image on the monitor, not
the size with edge borders, or the size of the tube. The simplistic
`my monitor is 17", just turn 17" into centimeters' doesn't work;
that 17" is a marketing figure and has only a vague connection to
reality. Get out a ruler and measure it.

@item @code{-pixelwidth}, @code{-pixelheight}
Lets you specify the exact size of a single pixel, if XaoS cannot
determine this for itself from your screen size.
@end table

These options are used by some other parts of XaoS as well, so you should
use them even when you don't want to see stereograms. You should probably
write a small starting script (or alias, or shortcut; whatever your environment
uses) that passes the correct parameters to XaoS.

If the window is @emph{smaller than 8cm in any direction}, you will probably be
unable to see anything; make the window bigger.

The correct way to see XaoS stereograms is:
@table @strong
@item 1
Start XaoS with options specifying the exact size of your screen or one pixel on it
@item 2
Sit 60cm away from monitor
@item 3
If you use a windowed environment, resize XaoS' window to make it wider than, say, 15 cm.
@item 4
Enable the filter (by pressing @code{E})
@item 5
focus on a point far away from the monitor (try to use your
own reflection, if your monitor's not antireflective); the random blurring should
eventually fall into the pattern of a Mandelbrot set.
@item 6
Carefully use your mouse to zoom into interesting areas
(it is easy to lose concentration when you are not trained; but you can use
the autopilot...)
@item 7
Enjoy animation :)
@end table

If you still can't see the stereograms, it could be that the fractal, or your eye,
is deformed. A deformed fractal can be caused by your specifying your monitor size
wrongly. Visual problems that damage depth perception, as well as problems like
astigmatism, can make it impossible to see stereograms at all.


@emph{Available as}: menu item, command line option

@node interlace,  blur,  stereogram,  mfilter


@appendixsubsec Interlace filter

The interlace filter halves the horizontal resolution, and in each frame alternates
between drawing only the even and only the odd lines. This speeds up the
calculation, and in higher resolutions produces a motion-blur-like effect.

@emph{Available as}: menu item, command line option

@node blur,  emboss,  interlace,  mfilter


@appendixsubsec Motion blur

Motion blur mixes the current frame with previous ones to produce a
motion-blur effect. It might be rather slow in 16bpp truecolor modes. The best
results can probably be seen in 8bpp modes, so you might want to enable the
palette filter first.

@emph{Available as}: menu item, command line option

@node emboss,  palettef,  blur,  mfilter


@appendixsubsec Emboss

This is a standard emboss filter, as seen in programs such as the GIMP or
Photoshop. It produces especially nice results with the smooth
outcoloring mode. @xref{outcoloring}.

@emph{Available as}: menu item, command line option

@node palettef,  anti,  emboss,  mfilter


@appendixsubsec Palette emulator

XaoS can work in either palette or truecolor mode. Both modes
have advantages and disadvantages. Palette mode allows effects such as palette
rotation, while truecolor mode allows smoother incoloring
and outcoloring modes and the
truecolor coloring modes. If your display is truecolor, you
can enable this filter to get palette emulation (albeit not as cheaply as in
a real paletted mode).

@emph{Available as}: menu item, command line option

@node anti,  truecolor,  palettef,  mfilter


@appendixsubsec Antialiasing

Antialiasing is a technique to increase image quality by eliminating jagged
edges. XaoS calculates four values for each pixel (on the subpixel boundaries)
and uses the average of them for the pixel value.

This filter slows XaoS down a @emph{lot} and greatly increases memory
requirements. It is useful mainly when you want to save images and want to make
them look as nice as possible. Antialiasing also helps a lot when you want to
encode JPEG or MPEG files; they are much shorter if antialiased (MPEG and JPEG
hate jagged edges).

@emph{Available as}: menu item, command line option

@node truecolor,  ,  anti,  mfilter


@appendixsubsec Truecolor emulator

XaoS can work in either palette or truecolor mode. Both modes
have advantages and disadvantages. Palette mode allows effects such as palette
rotation, while truecolor mode allows smoother incoloring
and outcoloring modes and the
truecolor coloring modes. If your display is 8bpp, you can enable
this filter to get truecolor emulation (but, obviously, not with as many colors
as a real truecolor display).

More information about filters

@emph{Available as}: menu item, command line option

@node ui,  misc,  mfilter,  menus



@appendixsec UI

This menu contains functions to control the user interface layer of XaoS:
zooming speed, the autopilot, realtime status information, and so on.

@menu 
* speed::	Zooming speed
* letterspersec::	Letters per second
* autopilot::	Autopilot
* recalculate::	Recalculate
* interrupt::	Interrupt
* nogui::	Disable XaoS's builtin GUI
* status::	Status
* ministatus::	Ministatus
@end menu 
@node speed,  letterspersec,  ,  ui


@appendixsubsec Zooming speed
@defun speed float 
@end defun

Change zooming speed, where 1 is the default, 2 means twice as fast, and so on.

@emph{Available as}: menu item, command line option, command

In the scripting language you can use the following functions for better
control:
@defun maxstep float 
@end defun

Selects the zooming/unzooming speed. The parameter specifies how much of the
range will be removed each twentieth of a second; 0 means nothing, 1 means
everything (the parameter obviously has to be less than 1).
Higher values mean faster zooming.

@emph{Available as}: command
@defun speedup float 
@end defun
When zooming/unzooming, every twentieth of a second the @code{speedup}
value is added to the current step until @code{maxstep} is reached.
So this value selects the rate at which zooming stops and starts.
Both these functions are more for internal use of XaoS then for manually
written scripts, but they could come in useful nonetheless.

@emph{Available as}: command

@node letterspersec,  autopilot,  speed,  ui


@appendixsubsec Letters per second
@defun letterspersec integer 
@end defun

Speed of subtitles for the @code{textsleep} function.
The user can set this value to suit; it can also be changed with the left and
right arrow keys during animation replay.

@emph{Available as}: command line option, command

@node autopilot,  recalculate,  letterspersec,  ui


@appendixsubsec Autopilot
@defun autopilot bool 
@end defun

To make XaoS yet more impressive, we made a special autopilot mode that
automatically drives into interesting boundaries of the set; you should
press @code{A}, play your favorite music, drink coffee and relax. I never
tried this but it should be really relaxing! Many pictures in the XaoS
gallery were discovered using the autopilot.

The autopilot also has some additional features. It backtracks if the
zoomed picture is not interesting anymore, and can detect when it's zoomed
into really a boring part of the fractal or reached the limit of floating
point arithmetic on the platform, and restart zooming from the top.

@emph{Available as}: menu item, command line option, command

@node recalculate,  interrupt,  autopilot,  ui


@appendixsubsec Recalculate
@defun recalculate 
@end defun

Recalculate current fractal. This should be used when the fractal on the
screen is strange because of error propagation caused by
solid guessing. @xref{range}.

@emph{Available as}: menu item, command line option, command

@node interrupt,  nogui,  recalculate,  ui


@appendixsubsec Interrupt
@defun interrupt 
@end defun

Interrupt current calculation.

@emph{Available as}: menu item, command line option, command


@node nogui,  status,  interrupt,  ui


@appendixsubsec Disable XaoS's builtin GUI
@defun nogui bool 
@end defun

Disable XaoS menus and dialogs. This function should be used by external GUI
programs; these manipulate XaoS via a pipe, so the internal GUI should be
disabled at the same time. See the hacker's manual (@code{xaosdev.texinfo})
for more details.

@emph{Available as}: menu item, command line option, command

@node status,  ministatus,  nogui,  ui


@appendixsubsec Status
@defun status bool 
@end defun

Enable/disable status information. This displays some useful information
about the current fractal, such as viewpoint etc. (In low-resolution modes it
also almost completely obscures the current fractal...)

@emph{Available as}: menu item, command line option, command

@node ministatus,  ,  status,  ui


@appendixsubsec Ministatus
@defun ministatus bool 
@end defun

Enable/disable status line. This contains basic information such as how
much you are zoomed and the framerate.

@emph{Available as}: menu item, command line option, command

@node misc,  helpmenu,  ui,  menus



@appendixsec Misc
Miscellaneous functions.
@menu 
* command::	Command
* renderanim::	Render animation
* clearscreen::	Clear screen
* display::	Display fractal
* text::	Display text
* color::	Color
* xtextpos::	Horizontal text position
* ytextpos::	Vertical text position
* textposition::	Text position
* message::	Message
@end menu 
@node command,  renderanim,  ,  misc


@appendixsubsec Command

You can invoke all XaoS functions using a simple command language reminiscent
of Scheme. This option lets you run a single command. If you want to run more
than one, you might want to use an XaoS animation file instead;
they are written in the same language.

@emph{Available as}: menu item

@node renderanim,  clearscreen,  command,  misc


@appendixsubsec Render animation

Render an animation to image files. See How to encode MPEG files
for more information.

@emph{Available as}: menu item,
@node clearscreen,  display,  renderanim,  misc


@appendixsubsec Clear screen
@defun clearscreen 
@end defun

Clear the screen. To display the fractal again, use @code{display}. @xref{display}.
This function is mainly useful in tutorials and similar animations.

@emph{Available as}: menu item, command

@node display,  text,  clearscreen,  misc


@appendixsubsec Display fractal
@defun display 
@end defun

Display fractal. This functions reverses the effect of the @code{clearscreen},
line drawing and text output functions.

@emph{Available as}: menu item, command

@node text,  color,  display,  misc


@appendixsubsec Display text
@defun text string 
@end defun

Display the given text on the screen. This function is mainly useful in tutorials.
Text should be cleared by printing lots of spaces, or using the
@code{clearscreen}</a> or <a display>@code{display}
functions. You might also want to use the @code{textposition}
function to select the part of the screen to display the text on.

To wait for the user to read the text, you can use the @code{textsleep}
function.

Example:


@example
(clearscreen)
(textposition 'center 'middle)
(text "Welcome into my animation")
(textsleep)
(display)
@end example


@emph{Available as}: menu item, command line option, command

@node color,  textposition,  text,  misc


@appendixsubsec Color
@defun color keyword 
@end defun

Change text and line color. @emph{keyword} should be one of @code{'white},
@code{'black} and @code{'red}.

@emph{Available as}: menu item, command line option, command

@node textposition,  message,  color,  misc


@appendixsubsec Text position
@defun textposition keyword keyword 
@end defun

Select text position. The first keyword specifies the horizontal
position, the second the vertical position. The horizontal position should be
one of @code{'left}, @code{'center}, and @code{'right}.
The vertical should be one of @code{'top}, @code{'middle}, and @code{'bottom}.

@emph{Available as}: command line option, command

@node message,  ,  textposition,  misc


@appendixsubsec Message
@defun message string 
@end defun

This function is almost identical to the @code{text} function,
except that it uses message catalogs in the @code{catalog} directory to
translate messages into other languages. It should be used only in the multi-lingual
XaoS tutorials.

@emph{Available as}: command line option, command

@node helpmenu,  xtextpos,  misc,  menus



@appendixsec Help
This menu contains help and tutorials.

@node xtextpos,  ytextpos,  helpmenu,  menus



@appendixsec Horizontal text position
Select the horizontal position used to display text. @xref{text}.
It can be placed at the left, in the center or at the right.

@node ytextpos,  mformula,  xtextpos,  menus



@appendixsec Vertical text position
Select the vertical position used to display text. @xref{text}. It can be
placed at the top, in the middle or at the bottom of the screen.

@node mformula,  palettemenu,  ytextpos,  menus



@appendixsec formulae

Each escape time fractal has its own formula. XaoS supports the following
formulae:

@menu 
* mandel::	Mandelbrot
* mandel3::	Mandelbrot^3
* octal::	Octal
* newton::	Newton
* barnsley::	Barnsley1
* phoenix::	Phoenix
* magnet::	Magnet
@end menu 
@node mandel,  mandel3,  ,  mformula


@appendixsubsec Mandelbrot

The Mandelbrot set is the most famous escape time fractal ever. It has the
simple formula @math{z=z^2+c}. See the tutorial chapter.

@emph{Available as}: menu item, command line option

@node mandel3,  octal,  mandel,  mformula


@appendixsubsec Mandelbrot^3---Mandelbrot^6

This fractal is a simple modification of the standard
Mandelbrot set formula, using @math{z=z^3+c} instead of
@math{z=z^2+c}.

Other derivations of the Mandelbrot set (Mandelbrot^4 and so on) use even
higher powers. See the tutorial chapter.

@emph{Available as}: menu item, command line option
@node octal,  newton,  mandel3,  mformula


@appendixsubsec Octal

This is a less well-known fractal that Thomas discovered in Fractint.
It has an interesting shape when displayed in the alternative <a
mplane>planes</a>. See the tutorial chapter.

@emph{Available as}: menu item, command line option

@node newton,  barnsley,  octal,  mformula


@appendixsubsec Newton

This is Newton's approximation method for finding the roots of a polynomial. It
uses the polynomial @math{x^3=1} and counts the number of iterations needed
to reach the approximate value of the root. See the tutorial chapter.

This fractal doesn't have Julia sets, but XaoS is able to generate Julia-like
sets which are also very interesting (they are sometimes called ``Nova
formulae'').

@emph{Available as}: menu item, command line option

@node barnsley,  phoenix,  newton,  mformula


@appendixsubsec Barnsley1

This is a formula by Michael Barnsley. It produces very nice crystalline Julia
sets. See the tutorial chapter.

@emph{Available as}: menu item, command line option

@node phoenix,  magnet,  barnsley,  mformula


@appendixsubsec Phoenix

This formula produces very nice Julia sets.
See the tutorial chapter.

@emph{Available as}: menu item, command line option

@node magnet,  ,  phoenix,  mformula


@appendixsubsec Magnet

This is a formula that comes from theoretical physics.
It is derived from the study of theoretical lattices in the context of magnetic
renormalization transformations.
See the tutorial chapter.

@emph{Available as}: menu item, command line option

@node palettemenu,  ,  mformula,  menus



@appendixsec Palette
This menu contains functions to change the palette the fractal is displayed with.
@menu 
* defpalette::	Default palette
* randompalette::	Random palette
* palette::	Custom palette
* cycling::	Color cycling
* shiftpalette::	Shift palette
@end menu 
@node defpalette,  randompalette,  ,  palettemenu


@appendixsubsec Default palette
@defun defaultpalette number 
@end defun

Create a default palette. In the scripting language, @code{number} specifies
how much the palette is shifted by.

Note that changing the palette in truecolor modes forces recalculation of
the whole screen. To avoid this, you can enable the
palette emulation filter first.

@emph{Available as}: menu item, command line option, command

@node randompalette,  palette,  defpalette,  palettemenu


@appendixsubsec Random palette
@defun randompalette 
@end defun

Create a random palette. XaoS will automatically pick one of its
palette-generation algorithms and create one.

Note that changing the palette in truecolor modes forces recalculation of
the whole screen. To avoid this, you can enable the
palette emulation filter first.

@emph{Available as}: menu item, command line option, command

@node palette,  cycling,  randompalette,  palettemenu


@appendixsubsec Custom palette
@defun palette integer integer integer 
@end defun

A custom palette lets you re-create some of the random palettes. The first value
specifies the algorithm, which should currently be one of the following:
@table @strong
@item 0
Default palette
@item 1
Black to color gradient
@item 2
Black to color to white gradient
@item 3
Cubistic-like algorithm.
@end table
The seed specifies a random seed for the palette; different seeds generate
different palettes. The last value is the amount by which the palette is shifted.

Note that changing the palette in the truecolor modes forces recalculation of
the whole screen. To avoid this, you can enable the
palette emulation filter first.

@emph{Available as}: menu item, command line option, command

@node cycling,  shiftpalette,  palette,  palettemenu


@appendixsubsec Color cycling
@defun cycling bool 
@end defun

Color cycling is an old and simple effect to animate fractals. The Mandelbrot
set looks particularly nice when color-cycled. On truecolor displays, color
cycling fails to initialize (since those displays don't have a palette).
You can enable palette emulation filter to make it possible.

@emph{Available as}: menu item, command line option, command

In the user interface, colors can also be cycled in the opposite direction
with the ``@emph{Reversed color cycling}'' function.

To control the cycling speed, you coan use arrow keys or the
``@emph{Color cycling speed}'' function.

@emph{Available as}: menu item
@defun cyclingspeed integer 
@end defun

The parameter specifies the number of skips per second. It can be negative to
cycle in the opposite direction.

@emph{Available as}: menu item, command line option, command

@node shiftpalette,  ,  cycling,  palettemenu


@appendixsubsec Shift palette
@defun shiftpalette integer 
@end defun

Shift palette by the specified number of cells. This can be used to tune the
palette's position on the fractal. You can also use the
@emph{Shift one forward} and @emph{Shift one backward} functions
for fine-tuning. Note that shifted and rotated palettes could look different on
different displays (because they may have different palette sizes).

Shifting the palette on truecolor displays causes a recalculation of the screen.
To avoid this, you could use palette emulation filter. @xref{palettef}.

@emph{Available as}: menu item, command line option, command


@c ## menus controls ##
@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

@comment  node-name,  next,      previous,  up
@node authors, lists,menus ,Top

@appendix Credits
(alphabetically)
@table @strong
@item Eric Courteau (ecourteau@@cplus.fr)
francais.cat (translation of tutorials)
@item Jean-Pierre Demailly (Jean-Pierre.Demailly@@ujf-grenoble.fr)
Updates for French translation
@item Radek Doulik (rodo@@atrey.karlin.mff.cuni.cz)
GTK interface, windowid patches
@item Martin Dozsa (madsoft@@centrum.cz)
cs.po (Czech translation of menus)
@item Arpad Fekete (Fekete.Arpad.2@@stud.u-szeged.hu)
some new fractals, and the 'More formulae' menu
@item Tim Goodwin (tgoodwin@@cygnus.co.uk)
english.cat corrections
@item Ben Hines
autoconf suggestions, Mac OS X port
@item Jan Hubicka (jh@@ucw.cz)
Zooming routines, ugly interface, palettes, drivers, autopilot, filters, documentation, tutorials etc.
@item Jens Kilian (jjk@@acm.org)
BeOS driver, deutsch.cat
@item Thomas A. K. Kjaer (takjaer@@imv.aau.dk)
OS/2 ports (320x200 graphics and AA-lib)
@item Zoltan Kovacs (kovzol@@math.u-szeged.hu)
Internationalization, Hungarian translations, finalizing version 3.1, bug fixes, web design, current maintainer
@item Zsigmond Kovacs
Fractal examples
@item J. B. Langston III (jb.langston@@gmail.com)
Native Mac OS X port (from version 3.2.2)
@item Andreas Madritsch (amadritsch@@datacomm.ch)
New fractal types, bailout, many fixes
@item Giorgio Marazzi (gmarazzi@@vtr.net)
Improvements and fixes for espanhol.cat
@item Thomas Marsh
First zoomer, formulae, planes, X11 driver, inversions, many ideas
@item Dominic Mazzoni (dmazzoni@@cs.cmu.edu)
Macintosh port (version 2.0)
@item David Meleedy
Grammatical and spelling fixed version of @code{xaos.6}
@item Paul Nasca (zynaddsubfx@@yahoo.com)
Ministatus improvement
@item Nix (nix@@esperi.demon.co.uk)
Grammatical and spelling fixed version of @code{xaos.hlp} and other files
@item Terje Pedersen (terjepe@@login.eunet.no)
Amiga port
@item Cesar Perez (oroz@@users.sourceforge.net)
Spanish translations
@item Fabrice Premel (premelfa@@etu.utc.fr)
Periodicity checking
@item Jan Olderdissen (jan@@olderdissen.com)
Win32 port
@item Daniel Skarda
Fractal examples
@item Marton Torok (marton.torok@@gmail.com)
Small fixes for pipes
@item Pavel Tzekov (paveltz@@csoft.bg)
Win32 support
@item Charles Vidal
Tcl/Tk interface
@item Tapio K. Vocaldo (taps@@rmx.com)
Macintosh port
@item Philippe Wautelet (p.wautelet@@fractalzone.be)
Bug fixes for version 3.1.1, French translation, gcc 4.0 fixes
@end table

To contact the authors you can also use the mailing lists. @xref{lists}.
@c ## appendix authors ##

@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@comment  node-name,  next,      previous,  up
@node lists, index ,authors ,Top

@appendix Mailing-lists:
Until 1999 (or so) there was a high traffic mailing list
on a mail server located in Czech Republic. Unfortunately,
the server with its mailing lists no longer works.

In 2001 XaoS moved to the SourceForge developer site
and now there are 3 new mailing lists. Unfortunately,
at the time of writing this documentation its traffic
is about 0. Hopefully the development will continue
using these mailing lists. Namely,
@table @strong
@item xaos-announce@@lists.sourceforge.net,
@item xaos-devel@@lists.sourceforge.net,
@item xaos-discuss@@lists.sourceforge.net.
@end table

Please feel free to join any or all of these
mailing lists and share your ideas with the developers.

@c ## appendix lists ##

@c %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@comment  node-name,  next,      previous,  up
@node index,  ,lists ,Top
@unnumbered Index of functions

@printindex fn


@contents
@bye
