[pstricks] PSTricks Coordinate Computations and Nodes

[Herbert Voss]

Randy Yates wrote:

> It Would Be Nice (TM) if ... PSTricks allowed coordinate
> computations using defined nodes. For example,
> 
> \pnode(!0 0){MyNode}
> 
> and then
> 
> \pnode(!MyNode.x 4 add MyNode.y -2 add){MySecondNode}
> 
> (as just an example - any PSTricks object that permitted special coordinates
> would do).
> 
> Is this possible?

\documentclass{minimal}
\usepackage{pstricks,pst-node}
\SpecialCoor
\makeatletter
\def\GetCenter#1{ tx at NodeDict begin /N@#1 load GetCenter end
  \pst at number\psyunit mul /#1.y ED
  \pst at number\psxunit mul /#1.x ED }
\makeatother
\begin{document}

\pnode(!0 0){MyNode}%
%
\pnode(! \GetCenter{MyNode} 	% x y of MyNode
   MyNode.x 2 sub MyNode.y 4 add){MySecondNode}

\ncline[linecolor=red]{<->}{MyNode}{MySecondNode}

\end{document}


Herbert


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