Why does \pscustom fail to fill the enclosed region?

Question

\documentclass[pstricks,border=12pt]{standalone}
\usepackage{pstricks-add}

\def\Major{3}% semi major
\def\Minor{2}% semi minor
\def\Xo{4}% distance from origin to ellipse center
\def\Theta{60}


\pstVerb
{
    /Major \Major\space def
    /Minor \Minor\space def
    /Xo \Xo\space def
    /Theta \Theta\space def 
    /PtX1 180 Theta sub cos Major mul Xo add def
    /PtY1 180 Theta sub sin Minor mul def
    /PtX2 -180 cos Major mul Xo add def
    /PtY2 0 def
}

\begin{document}

\begin{pspicture}[showgrid](-\Major,-\Minor)(\Major,\Minor)
    \psset{linecolor=red}
    %\pscustom[fillstyle=solid,fillcolor=cyan]
    {%
        \pnode(!Xo 0){O}%
        \pnode(!PtX1 PtY1){A}%
        \pnode(!PtX2 PtY2){B}%      
        \psline(0,0)(0,0|A)(A)%
        \psellipticarc[correctAngle=true,origin={O}](O)(!Major Minor){(A)}{(B)}%
        \psline(B)(0,0)%
    }
\end{pspicture} 

\end{document}

Edit: I found almost the same issue here, the problem is that I still don't understand what Herbert answered there. In PSTricks manual, there are no detailed explanation about those topics.

Answer 1

I guess the problem is that the path is not a continous path that can be filled. Instead they are distinct line segments which are probably filled but not displayed since the result is a one dimensional object.

You can zoom in to see the problem on the corners. So fixing the order of that path such that there are no jumps seems like working. But I couldn't get the {(A)}{(B)} syntax working.

\documentclass[pstricks,border=12pt]{standalone}
\usepackage{pstricks-add}

\def\Major{3}% semi major
\def\Minor{2}% semi minor
\def\Xo{4}% distance from origin to ellipse center
\def\Theta{60}

\pstVerb
{
    /Major \Major\space def
    /Minor \Minor\space def
    /Xo \Xo\space def
    /Theta \Theta\space def
    /Alpha 180 Theta sub def
    /PtX1 Alpha cos Major mul Xo add def
    /PtY1 Alpha sin Minor mul def
    /PtX2 Major neg Xo add def
    /PtY2 0 def
}
\begin{document}
\begin{pspicture}[showgrid](0,-1)(3,2)
    \psset{linecolor=red}
    \pnode(!Xo 0){O}
    \pnode(!PtX1 PtY1){A}
    \pnode(!PtX2 PtY2){B}
    \pscustom[fillstyle=solid,fillcolor=cyan]
    {
        \psline(B)(0,0)(0,0|A)(A)
        \psellipticarc[correctAngle=false](O)(!Major Minor){!Alpha}{180}
        \closepath
    }
\end{pspicture}
\end{document}

Answer 2

This is the answer!

\documentclass[pstricks,border=12pt]{standalone}
\usepackage{pstricks-add}

\def\Major{3}% semi major
\def\Minor{2}% semi minor
\def\Xo{4}% distance from origin to ellipse center
\def\Theta{60}


\pstVerb
{
    /Major \Major\space def
    /Minor \Minor\space def
    /Xo \Xo\space def
    /Theta \Theta\space def 
    /PtX1 180 Theta sub cos Major mul Xo add def
    /PtY1 180 Theta sub sin Minor mul def
    /PtX2 -180 cos Major mul Xo add def
    /PtY2 0 def
}

\begin{document}

\begin{pspicture}[showgrid](-\Major,-\Minor)(\Major,\Minor)
    \psset{linecolor=red}
    \pnode(!Xo 0){O}
    \pnode(!PtX1 PtY1){A}
    \pnode(!PtX2 PtY2){B} 
    \pnode(0,0){Origin}  
    \pscustom[fillstyle=solid,fillcolor=cyan,origin={O}]
    {
        \psline(Origin)(Origin|A)(A)
        \psellipticarc[dimen=middle](O)(!Major Minor){(A)}{(B)}%middle must be set!
        \closepath
    }
\end{pspicture} 

\end{document}