%% $Id: pst-lsystem-doc.tex 820 2018-09-26 09:52:39Z herbert $
\documentclass[fontsize=11pt,english,BCOR=10mm,DIV=12,bibliography=totoc,parskip=false,
headings=small, headinclude=false,footinclude=false,oneside,abstract=on]{pst-doc}
\usepackage{pst-lsystem}
\let\pstFV\fileversion
\usepackage{dtk-logos}
\usepackage{xltabular}
\renewcommand\bgImage{%
\begin{pspicture}(-2,-0.5)(3,6)
\pslsystem[
Start=Y,
X={X[-FFF][+FFF]FX},
Y={YFX[+Y][-Y]},
Angle=25,
N=6,
Ftype=1,
BaseLength=2.5pt,
usecolor=2](0,0)
\psdot(0,0)
\end{pspicture}
}
\addbibresource{\jobname.bib}
\lstset{language=PSTricks,
morekeywords={pslsystem},basicstyle=\footnotesize\ttfamily,
literate=%
{Ö}{{\"O}}1
{Ä}{{\"A}}1
{Ü}{{\"U}}1
{ß}{{\ss}}1
{ü}{{\"u}}1
{ä}{{\"a}}1
{ö}{{\"o}}1
{~}{{\textasciitilde}}1
}
\begin{document}
\title{\texttt{pst-lsystem}}
\subtitle{Creating images, based on the Lindenmayer-system; v.\pstFV}
\author{Herbert Voß}
\docauthor{}
\date{\today}
\maketitle
\tableofcontents
\begin{abstract}
\noindent
\LPack{pst-lsystem} loads by default the following packages: \LPack{pst-xkey}, and, of course \LPack{pstricks}.
All should be already part of your local \TeX\ installation. If not, or in case
of having older versions, go to \url{
http://www.CTAN.org/} and load the newest version.
\vfill\noindent
Thanks to \\
Michel Charpentier,
and last but not least
\url{
http://mathworld.wolfram.com}.
\end{abstract}
\clearpage
\section{Introduction}
A L-system or Lindenmayer system is a parallel rewriting system and a type of
formal grammar. An L-system consists of an alphabet of symbols that can be used
to make strings, a collection of production rules that expand each symbol into
some larger string of symbols, an initial »axiom« string from which to begin construction,
and a mechanism for translating the generated strings into geometric structures.
L-systems were introduced and developed in 1968 by Aristid Lindenmayer,
a Hungarian theoretical biologist and botanist at the University of Utrecht.~\cite{wikipedia}
\section{Usage}
There are no optional arguments for the package:
\begin{verbatim}
\usepackage{pst-lsystem}
\end{verbatim}
There is only one command:
\begin{BDef}
\Lcs{pslsystem}\OptArgs\Largr{x,y}
\end{BDef}
If the coordinates for the origin are missing, then $(0,0)$ is assumed. The L-System ist
defined by the three functions $F$, $X$, and $Y$. At least one function must be given.
\subsection{Optional arguments}
The following optional arguments for the macro are possible:
\begin{xltabular}{\linewidth}{@{} l l X @{}}\toprule
\emph{name} & \emph{default} & \emph{menaing}\\\midrule
\Lkeyword{F} & & Rule $F\rightarrow(F)$\\
\Lkeyword{X} & & Rule $X\rightarrow(F,X,Y)$\\
\Lkeyword{Y} & & Rule $Y\rightarrow(F,X,Y)$\\
\Lkeyword{Start} & & Startrule $S\rightarrow(F,X,Y)$\\
\Lkeyword{Angle} & 45 & Angle for the drection change\\
\Lkeyword{N} & 5 & Number of the recursive calls\\
\Lkeyword{Ftype} & 4 & How the F-rule should be handled\\
\Lkeyword{BaseLength} & 1mm & The length of a base line, created by the ruke F (Forward)\\
\Lkeyword{usecolor} & 0 & Which color should be used for the lines.\\
%\define@key[psset]{pst-lsystem}{order}[5]{\pst@getint{#1}\psk@lsystem@order}
%\define@key[psset]{pst-lsystem}{factor}[2]{\pst@checknum{#1}\psk@lsystem@factor}
% Size (the smaller, the bigger), no need to be changed, normally
%\define@key[psset]{pst-lsystem}{size}[4]{\pst@getint{#1}\psk@lsystem@size}
%\define@key[psset]{pst-lsystem}{type}[0]{\pst@getint{#1}\psk@lsystem@type}
\bottomrule
\end{xltabular}
\bigskip
If the rules contain square brackets then it must be enclosed by braces:
\verb|X=F[-X]| is wrong and \verb|X={F[-X]}| is correct.
\subsection{Different types for the F-rule}
It depends to the given rule(s) what kind of the F-type must be used.
There are five possibilities:
\begin{xltabular}{\linewidth}{@{} >{\ttfamily}l X @{}}
0 & $F\rightarrow \textrm{draw line element}$ \\
& in PostScript: \verb|/F { D } def|\\
1 & $F\rightarrow \textrm{If loop variable }=0 \textrm{ then draw line element}$\\
& in PostScript: \verb|/F { 0 eq { D } if } def|\\
2 & $F\rightarrow \textrm{If loop variable }=0 \textrm{ then draw line element and keep variable}$\\
& in PostScript: \verb|/F { dup 0 eq { D } if } def|\\
3 & $F\rightarrow \textrm{draw line element and delete current loop variable}$\\
& in PostScript: \verb|/F { pop D } def|\\
4 & $F\rightarrow \textrm{If loop variable }=0 $ then draw line element! If not $=0$ decrease loop variable, duplicate it
$n-1$ times (n is the number of functions in $F$) and put F-rule on stack\\
& in PostScript: \verb|/F { dup 0 eq { D }{ 1 sub N 1 sub {dup} repeat F-rule } ifelse pop } def|
\end{xltabular}
\iffalse
\begin{verbatim}
\ifcase\psk@lsystem@Ftype
/F { D } def % type 0
\or % 1
/F { 0 eq { D } if } def
\or % 2
/F { dup 0 eq { D } if } def
\or % 3
/F { pop D } def
\else % 4
/F { dup 0 eq { D }{ 1 sub \psk@lsystem@Fnumber {dup} repeat \psk@lsystem@F } ifelse pop } def
\fi
\end{verbatim}
\fi
The function D does nothing else than drawing a line in the current direction.
Its length is given by the optional parameter BaseLength.
\subsection{Color}
There are four predefined color modes, where mode=0 is no color.
\psset{linewidth=0.1pt}
\section{Examples}
\subsection{Dragon}
\begin{LTXexample}[pos=r]
\begin{pspicture}[showgrid=true](-2,-1.5)(4,6)
\pslsystem[
X=-FX++FY-,
Y=+FX--FY+,
Ftype=1,
Start=X,
Angle=45,
N=9,
BaseLength=2mm](0,0)
\psdot(0,0)
\end{pspicture}
\end{LTXexample}
\subsection{Hilbert}
\begin{LTXexample}[pos=r]
\begin{pspicture}[showgrid=true](-1,-0.5)(4,4)
\pslsystem[
X=-YF+XFX+FY-,
Y=+XF-YFY-FX+,
Ftype=3,
Start=X,
Angle=90](0,0)
\psdot(0,0)
\end{pspicture}
\end{LTXexample}
\clearpage
\subsection{Kochflake}
If the rule for \Lkeyword{Start} has more than one function name, one has to repeat
the number of iterations, which is \Lkeyword{N}, before every following function, but not
for the first one. That is done already internally:
\begin{LTXexample}[pos=r]
\begin{pspicture}[showgrid=true](-2,-.5)(5,6)
\pslsystem[
Start=F--NF--NF,% repeat number of iterations N
F=F+F--F+F,
Angle=60,
N=4,
BaseLength=2pt,
linecolor=red](0,0)
\psdot(0,0)
\end{pspicture}
\end{LTXexample}
\subsection{Plant 1}
\begin{LTXexample}[pos=r]
\begin{pspicture}[showgrid=true](-2,-2.3)(4,6)
\pslsystem[
Start=F,
F={FF-[-F+F+F]+[+F-F-F]},
Angle=22.5,
BaseLength=2pt,
usecolor=4](0,-2)
\psdot(0,-2)
\end{pspicture}
\end{LTXexample}
\clearpage
\subsection{Plant 2}
\begin{LTXexample}[pos=r]
\begin{pspicture}[showgrid=true](-3,-2.3)(2,6)
\pslsystem[
Start=X,
X={F-[[X]+X]+F[+FX]-X},
F=FF,
Angle=22.5,
N=6,
BaseLength=1.25pt,
usecolor=3](0,-2)
\psdot(0,-2)
\end{pspicture}
\end{LTXexample}
\subsection{Plant 3}
\begin{LTXexample}[pos=r]
\begin{pspicture}[showgrid=true](-2,-2.5)(2,5)
\psset{xunit=3}
\pslsystem[
Start=F,
F={F[+F]F[-F][F]},
Angle=20,
usecolor=3](0,-2)
\psdot(0,-2)
\end{pspicture}
\end{LTXexample}
\clearpage
\clearpage
\subsection{Plant 4}
\begin{LTXexample}[pos=r]
\begin{pspicture}[showgrid=true](-2,-0.5)(3,6)
\pslsystem[
Start=Y,
X={X[-FFF][+FFF]FX},
Y={YFX[+Y][-Y]},
Angle=25,
N=6,
Ftype=1,
BaseLength=2.5pt,
usecolor=2](0,0)
\psdot(0,0)
\end{pspicture}
\end{LTXexample}
\subsection{Plant 5}
\begin{LTXexample}[pos=r]
\begin{pspicture}[showgrid=true](-3,-.5)(3,9)
\pslsystem[
Start=X,
X={F[+X][-X]FX},
F={FF},
Angle=25,
N=7,
BaseLength=1pt,
usecolor=2](0,0)
\psdot(0,0)
\end{pspicture}
\end{LTXexample}
\clearpage
\clearpage
\subsection{Plant 6}
\begin{LTXexample}[pos=r]
\begin{pspicture}[showgrid=true](-3,-.5)(3,9)
\pslsystem[
Start=X,
X={F[+X]F[-X]+X},
F={FF},
Angle=20,
N=7,
BaseLength=1pt,
usecolor=2](0,0)
\psdot(0,0)
\end{pspicture}
\end{LTXexample}
\subsection{Plant 7}
\begin{LTXexample}[pos=r]
\begin{pspicture}[showgrid=true](-3,-.5)(3,9)
\pslsystem[
Start=F,
F={F[+F]F[-F]F},
Angle=25,
BaseLength=1pt,
usecolor=2](0,0)
\psdot(0,0)
\end{pspicture}
\end{LTXexample}
\clearpage
\subsection{Plant 8}
\begin{LTXexample}[pos=r]
\begin{pspicture}[showgrid=true](-4,-.5)(5,9)
\pslsystem[
Start=F,
F={F[+F[+F][-F]F][-F[+F][-F]F]F[+F][-F]F},
Angle=30,
BaseLength=1pt,
usecolor=4](0,0)
\psdot(0,0)
\end{pspicture}
\end{LTXexample}
\subsection{Special case}
\begin{LTXexample}[pos=r]
\begin{pspicture}[showgrid=true](-2,-0.5)(1,4)
\pslsystem[
Start=X,
F=FF,
X=F+X-F-X+F,
Angle=90,
N=6,
BaseLength=1pt](0,0)
\psdot(0,0)
\end{pspicture}
\end{LTXexample}
\clearpage
\section{List of all optional arguments for \nxLPack{pst-lsystem}}
\xkvview{family=pst-lsystem,columns={key,type,default}}
\bgroup
\raggedright
\nocite{*}
\printbibliography
\egroup
\printindex
\end{document}
% F=F+FF-FF-F-F+F+FF-F-F+F+FF+FF-F,