%% 
%%  A DANTE-Edition example
%% 
%% 
%%  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{201.70511pt}
\setlength\parindent{0pt}

\usepackage{pstricks-add}

\begin{document}
\begin{pspicture}[showgrid](1,1)(5,5)
  \psset{linecolor=red}
  \psline{o-o}(1,1)(5,5)
  \psLNode(1,1)(5,5){0.75}{P1}\qdisk(P1){4pt}
  \psset{linecolor=blue}
  \psline{o-o}(4,3)(2,5)
  \psLNode(4,3)(2,5){-0.5}{P2}\qdisk(P2){4pt}
\end{pspicture}
\end{document}