[pstricks] nodes and plot

[Herbert Voss]

Christophe Jorssen wrote:
>>If you still are interested in a file solution, let me know.
>>I have it run.
> 
> 
> I'm interested by your solution, thanks. I think I misunderstood what your
> explained...

I 'm working on a solution without writing the values into a
file. I have the problem that the nodes must be defined
as /N@<m>... inside PostScript and I do not really know how
to handle such "dynamical" function names inside PostScript,
where m=0,1,2,3,....

Attached the "file" solution.
- build the ps-file.
- run once "gs file.ps", this is important otherwise
   the data file is not successfully build.
- now you can run the TeX file as usual, as dvi/ps/pdf
   just as you like. instead of the parametricplot I use
   now the data records of the file with \fileplot

this is the only problem, that a PostScript interpreter
(e.g. ghostscript) is needed to save the data records.
Maybe that this is a real problem to what you where
looking for.


Herbert


\documentclass[a4paper]{article}
\usepackage{pstricks,pst-plot,pst-node,pst-key}
\SpecialCoor
\makeatletter
\newif\ifPst at saveData% write the coordinates into a file?
\define at key{psset}{saveData}[true]{%
         \@nameuse{Pst at saveData#1}%
}
\psset{saveData=false}
%
\def\saveDataAsNodes{%
	\psset{unit=1pt}
	\typeout{Open file \FileName}
	\openin 7 = \FileName
	\newcount\nrepeat\nrepeat=\psk at plotpoints
	\loop
		\def\NodeName{N\the\nrepeat}
		\ifnum\nrepeat>-1
		\read 7 to \Data
		\pnode(\Data){\NodeName}
		\typeout{\NodeName ->> (\Data)}
		\advance\nrepeat by -1
	\repeat
	\closein 7%
}
%
\def\parametricplot at i#1#2#3{%
   \pst at killglue
   \begingroup
    \use at par
     \@nameuse{beginplot@\psplotstyle}%
     \ifPst at saveData\typeout{>>> saveData <<<}\else\typeout{>>> no 
saveData <<<}\fi%
	\addto at pscode{%
	  \ifPst at saveData
		  /Datei (\FileName) (w) file def
		\fi
	  \psplot at init
       /t #1 def
       /t1 #2 def
       /dt t1 t sub \psk at plotpoints div def
       /xy {
         #3
         \pst at number\psyunit mul /x exch def
         \pst at number\psxunit mul /y exch def
		\ifPst at saveData
			/xString x 10 string cvs def
			/yString y 10 string cvs def
			Datei xString writestring
			Datei (, ) writestring
			Datei yString writestring
			Datei (\string\n) writestring
		\fi
		x y
	  } def%
	}%
     \gdef\psplot at init{}%
     \@pstfalse
     \@nameuse{testqp@\psplotstyle}%
     \if at pst\parametricplot at ii\else\parametricplot at iii\fi
	\ifPst at saveData
		\addto at pscode{ Datei closefile }%
	\fi
   \endgroup
   \ignorespaces}
\makeatother

\begin{document}

\begin{center}
\begin{pspicture}(-2,-2)(2,2)
	\def\FileName{data.ps}%
	\typeout{>>> Filename: \FileName <<<}%
	% saveData=true saves all points as a x|y data pair.
	\IfFileExists{\FileName}{%
		\typeout{>>> \FileName\ exists <<<}%
		\saveDataAsNodes%
		\fileplot{\FileName}%
		\psline[linecolor=red](N1)(N5)(N23)(N12)(N49)(N13)(N22)(N44)%
	}{  \typeout{>>> \FileName\ doesn't exist <<<}%
		\parametricplot[unit=3,saveData=true]{0}{360}{t sin t cos}%
	}%
\end{pspicture}
\end{center}
\end{document}



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