[pstricks] area between curves??

Fri Apr 6 18:55:15 CEST 2007

Hi,
Can someone tell me why the first set of commands shades the area
between the two curves, yet the second only shades the region between
y=1 and y=4? The only difference is ftnA which changes from -x^2 + 4 to
-x^2 + 5, but it is still in the bounds of the psframe, or so I thought...

\begin{center}
\begin{pspicture}(-2,-0.5)(2,6)
\def\ftnA{x 2 exp}
\def\ftnB{x 2 exp neg 4 add}
\begin{psclip}
{
\pscustom[linestyle=none]{
\psplot{-2}{2}{\ftnA}}
\pscustom[linestyle=none]{
\psplot{2}{-2}{\ftnB}}
}
\psframe*[linecolor=blue](-2,0)(2,5)
\end{psclip}
\psaxes[subticks=0,labelFontSize=\footnotesize]{->}(0,0)(-2,-0.5)(2,6)
\psplot{-2}{2}{\ftnA}
\psplot{-2}{2}{\ftnB}
%  \uput[-90](2,0){$\bm{x}$}
%  \uput[180](0,6){$\bm{y}$}
\end{pspicture}
\end{center}

\begin{center}
\begin{pspicture}(-2,-0.5)(2,6)
\def\ftnA{x 2 exp}
\def\ftnB{x 2 exp neg 5 add}
\begin{psclip}
{
\pscustom[linestyle=none]{
\psplot{-2}{2}{\ftnA}}
\pscustom[linestyle=none]{
\psplot{2}{-2}{\ftnB}}
}
\psframe*[linecolor=blue](-2,0)(2,5)
\end{psclip}
\psaxes[subticks=0,labelFontSize=\footnotesize]{->}(0,0)(-2,-0.5)(2,6)
\psplot{-2}{2}{\ftnA}
\psplot{-2}{2}{\ftnB}
%  \uput[-90](2,0){$\bm{x}$}
%  \uput[180](0,6){$\bm{y}$}
\end{pspicture}
\end{center}

Thanks,
Derek