%% 
%%  A DANTE-Edition example
%% 
%%  Example 16-02-1 on page 228.
%% 
%%  Copyright (C) 2011 Herbert Voss
%% 
%%  It may be distributed and/or modified under the conditions
%%  of the LaTeX Project Public License, either version 1.3
%%  of this license or (at your option) any later version.
%% 
%%  See http://www.latex-project.org/lppl.txt for details.
%% 
%% 
%% ==== 
% Show page(s) 1
%% 
\documentclass[]{article}
\pagestyle{empty}
\setlength\textwidth{375.57637pt}
\setlength\parindent{0pt}
\usepackage{pstricks,pst-node}
\def\Square{\rule{1cm}{1cm}}
\def\BildI{%
  \begin{pspicture}[showgrid](5,1)
  \Rnode{A}{\Square}\hspace{3cm}\Rnode{B}{\Square}
  \ncline[linecolor=red,style=line]{A}{B}
\end{pspicture}}
\def\BildII{%
  \begin{pspicture}[showgrid](5,4)
  \rput[lb](0,0){\Rnode{A}{\Square}\hspace{3cm}\Rnode[vref=3cm]{B}{\Square}}
  \psframe*[linecolor=black!20](4,3)(5,4)
  \pcline[linecolor=red,linestyle=dotted,linewidth=2pt](A)(B)
  \ncline[linecolor=red,style=line]{A}{B}
  \pnode(4,0.7ex){C}
  \ncline[linecolor=blue,style=line]{A}{C}
  \pcline{->}(4.5,0.5)(4.5,3.5)\uput[0](3.5,2){vref}
  \end{pspicture}}
\newpsstyle{line}{linewidth=2pt,arrowscale=2,arrows=->}
\SpecialCoor

\usepackage{pstricks,pst-node}

\begin{document}
\psscalebox{0.8}{\BildI}\\[12pt]
\psscalebox{0.8}{\BildII}\\[12pt]
\psscalebox{0.8}{%
 \begin{pspicture}[showgrid](7,4)%
  \rput[lb](0,0){\Rnode{A}{\Square}\hspace{3cm}\Rnode[href=4,vref=3cm]{B}{\Square}}
  \psframe*[linecolor=black!20](4,3)(5,4)   \psframe*[linecolor=black!20](6,3)(7,4)
  \psline[arrows=->](4.5,3.5)(6.5,3.5)
  \uput[-90](5.5,3.5){href}
  \pcline[linecolor=red,linestyle=dotted,linewidth=2pt](A)(B)
  \ncline[linecolor=red,style=line]{A}{B}
  \pnode(4,0.7ex){C}
  \pcline{->}(4.5,0.5)(4.5,3.5)
  \uput[0](3.5,2){vref}
  \pcline[linecolor=white](3.5,0.5)(3.5,1)
  \ncline[linecolor=blue,style=line]{A}{C}
\end{pspicture}}
\end{document}
