<HTML><FONT FACE=arial,helvetica><HTML><FONT SIZE=2 PTSIZE=10 FAMILY="SANSSERIF" FACE="Arial" LANG="1">The problem of the transparency seems to arouse some interest and if according to the message of Jan Steffan, the problem seems to be solved in the new versions of GhostScript, it is a good news.<BR>
However, if you want to arrange it by yourself, it is possible.<BR>
This problem can be dealt with by the use of coding CMYK. When two surfaces of different colors are superimposed, the resulting color has as components the addition of the respective colors as in the example below.<BR>
It is the result of the superposition, on an overhead projector, of three transparencies.<BR>
Each transparency contains only diagram.<BR>
Is it possible to build something of more general? I subject this problem to you...<BR>
<BR>
%%%%%%%%%%%%%%%%%%%%%%%%%<BR>
% 14 juillet 2005<BR>
\documentclass{article}<BR>
\usepackage{pstricks}<BR>
\SpecialCoor<BR>
\newcommand{\CyanA}{0.5}<BR>
\newcommand{\MagentaA}{0}<BR>
\newcommand{\YellowA}{0.1}<BR>
\newcommand{\CyanB}{0.05}<BR>
\newcommand{\MagentaB}{0.4}<BR>
\newcommand{\YellowB}{0.1}<BR>
\newcommand{\CyanC}{0.2}<BR>
\newcommand{\MagentaC}{0.1}<BR>
\newcommand{\YellowC}{0.5}<BR>
\newcommand{\VeenA}{%<BR>
\psccurve(4;30)(4.2;90)(4.1;150)(4.2;210)(3.9;270)(4.2;330)}<BR>
\newcommand{\VeenB}{%<BR>
\psccurve(4.5;30)(4.3;90)(4.1;150)(4;210)(4.2;270)(4;330)}<BR>
\newcommand{\VeenC}{%<BR>
\psccurve(4;30)(4.1;90)(4.2;150)(4.3;210)(4.2;270)(4.1;330)}<BR>
% Denis Girou<BR>
\makeatletter<BR>
\newcommand{\NewColorCMYK}[2]{\@newcolor{#1}{#2 setcmykcolor}}<BR>
\makeatother<BR>
%<BR>
\newcommand{\VeenDiagramTransparency}{%<BR>
\NewColorCMYK{A}{\CyanA\space \MagentaA\space \YellowA\space 0}<BR>
\NewColorCMYK{B}{\CyanB\space \MagentaB\space \YellowB\space 0}<BR>
\NewColorCMYK{C}{\CyanC\space \MagentaC\space \YellowC\space 0}<BR>
\NewColorCMYK{AB}{\CyanA\space \CyanB\space add<BR>
\MagentaA\space \MagentaB\space add<BR>
\YellowA\space \YellowB\space add 0}<BR>
\NewColorCMYK{BC}{\CyanB\space \CyanC\space add<BR>
\MagentaB\space \MagentaC\space add<BR>
\YellowB\space \YellowC\space add 0}<BR>
\NewColorCMYK{AC}{\CyanA\space \CyanC\space add<BR>
\MagentaA\space \MagentaC\space add<BR>
\YellowA\space \YellowC\space add 0}<BR>
\NewColorCMYK{ABC}{\CyanA\space \CyanB\space add \CyanC\space add<BR>
\MagentaA\space \MagentaB\space add \MagentaC\space add<BR>
\YellowA\space \YellowB\space add \YellowC\space add 0}<BR>
\rput(1,-1){\psset{fillstyle=solid,fillcolor=B}\VeenB}<BR>
\rput(-2,0){\psset{fillstyle=solid,fillcolor=A}\VeenA}<BR>
\rput(2,2){\psset{fillstyle=solid,fillcolor=C}\VeenC}<BR>
% A inter B<BR>
\psclip{\rput(-2,0){\VeenA}}<BR>
\rput(1,-1){\psset{fillstyle=solid,fillcolor=AB}\VeenB}<BR>
\endpsclip%<BR>
% B inter C<BR>
\psclip{\rput(1,-1){\VeenB}}<BR>
\rput(2,2){\psset{fillstyle=solid,fillcolor=BC}\VeenC}<BR>
\endpsclip%<BR>
% A inter C<BR>
\psclip{%<BR>
\rput(-2,0){\VeenA}}<BR>
\rput(2,2){\psset{fillstyle=solid,fillcolor=AC}\VeenC}<BR>
\endpsclip%<BR>
% A inter B inter C<BR>
\psclip{\rput(-2,0){\VeenA}}<BR>
\psclip{\rput(1,-1){\VeenB}}<BR>
\rput(2,2){\psset{fillstyle=solid,fillcolor=ABC}\VeenC}<BR>
\endpsclip%<BR>
\endpsclip%<BR>
\rput(1,-1){\VeenB}<BR>
\rput(-2,0){\VeenA}<BR>
\rput(2,2){\VeenC}}<BR>
\begin{document}<BR>
\begin{center}<BR>
\begin{pspicture}(-4,-5)(4,4)<BR>
\VeenDiagramTransparency<BR>
\end{pspicture}<BR>
\renewcommand{\CyanA}{0.3}<BR>
\renewcommand{\MagentaA}{0.2}<BR>
\renewcommand{\YellowA}{0.1}<BR>
\renewcommand{\CyanB}{0.1}<BR>
\renewcommand{\MagentaB}{0.3}<BR>
\renewcommand{\YellowB}{0.3}<BR>
\renewcommand{\CyanC}{0.1}<BR>
\renewcommand{\MagentaC}{0}<BR>
\renewcommand{\YellowC}{0.6}<BR>
\renewcommand{\VeenA}{%<BR>
\psccurve(4;30)(4.2;90)(4.3;150)(3.9;210)(4.1;270)(3.7;330)}<BR>
\renewcommand{\VeenB}{%<BR>
\psccurve(4.2;30)(3.9;90)(4;150)(4.1;210)(4.2;270)(4;330)}<BR>
\renewcommand{\VeenC}{%<BR>
\psccurve(4.1;30)(3.8;90)(4.2;150)(3.9;210)(3.7;270)(4.1;330)}<BR>
\begin{pspicture}(-4,-4)(4,6)<BR>
\VeenDiagramTransparency<BR>
\end{pspicture}<BR>
\end{center}<BR>
\end{document}<BR>
<BR>
<BR>
Manuel Luque</FONT></HTML>