[pstricks] pst-slpe

[Cyrille Piatecki]

In pst-slpe we can find a large variety of method for coloring an area. 
But slope color from the left to the right. It will be usefull to have 
one for coloring from the right to the left, one from the bottom to the 
top and one from the top to the botom.

I need the two last for this pictures

\begin{center}
\begin{pspicture}(0,0)(14,5)
\psgrid
\psline{<->}(4,4.5)(4,.5)(10.2,.5)
%\psline[linestyle=dashed](4,2.5)(7,2.5)(7,.5)
\rput(10,4){$O_n$}
\rput(10,1){$D_n$}
\rput(10.4,.5){$q$}
\rput(7,.15){$q^\star$}
\rput(3.8,4.5){$p$}
\rput(3.8,1.4){$p_t$}
\psline[linestyle=dashed](4,1.4)(4.9,1.4)
\rput(3.8,2.5){$p^\star$}
\rput(7,.15){$q^\star$}
\psset{origin={4,.5}}
\psplot[algebraic,linecolor=blue,linewidth=1.4pt]{0}{6}{-.41 * x - 
0.03*x^2 + 3.5}
\psplot[algebraic,linecolor=red,linewidth=1.4pt]{0}{6}{.4 * x + 
0.035*x^2 + .5}
\pscircle[fillstyle=solid,fillcolor=green,linestyle=none](3,2.){3pt}
\pscustom[fillstyle=slope,linestyle=none,fading,slopebegin=white,slopeend=red]{
\psplot[algebraic]{1.1}{2}{.4 * x + 0.035*x^2 + .5}
\psplot[algebraic]{3}{4.7}{-.41 * x - 0.03*x^2 + 3.5}
\lineto(0.8,0.9)}

\psplot[algebraic,linecolor=blue,linewidth=1.4pt]{0}{6}{-.41 * x - 
0.03*x^2 + 3.5}
\psplot[algebraic,linecolor=red,linewidth=1.4pt]{0}{6}{.4 * x + 
0.035*x^2 + .5}
\pscircle[fillstyle=solid,fillcolor=green,linestyle=none](3,2.){3pt}
\end{pspicture}
\end{center}

(For herbert Voss, I have not taken time to thanks for ma last question 
and the deawing of a fonction with the intersection of a plane and the 
projection of the function because I use the very nice Bakoma and on my 
computer your code is not shown)

Thanks