什么原因导致 \pscustom 中的一系列 \pscurve 路径产生意外结果？

Question

我正在尝试填充 pstricks 中的一些自定义区域，结果让我有点惊讶。这是我的 MWE：

\documentclass[border=3mm]{standalone}
\usepackage{pstricks}
\begin{document}

\begin{pspicture}(-3,-2.3)(3,3)
\psclip[linestyle=none]{%   
\pscustom{
    \pscurve(-2.5,-2)(0,-1.5)(2.5,-2)
    \pscurve(2.5,-2)(0.9,0)(0,2)
    \pscurve(0,2)(-0.9,0)(-2.5,-2)
  }}
  \psframe*[linecolor=gray,opacity=0.6](-3,-3)(3,3)
\endpsclip
    \pscurve(-2.5,-2)(0,-1.5)(2.5,-2)
    \pscurve(2.5,-2)(0.9,0)(0,2)
    \pscurve(0,2)(-0.9,0)(-2.5,-2)
\end{pspicture}

\begin{pspicture}(-3,-2.3)(3,3)
\pscustom[fillstyle=solid,fillcolor=gray]{
    \pscurve(-2.5,-2)(0,-1.5)(2.5,-2)
    \pscurve(2.5,-2)(0.9,0)(0,2)
    \pscurve(0,2)(-0.9,0)(-2.5,-2)
  }
    \pscurve(-2.5,-2)(0,-1.5)(2.5,-2)
    \pscurve(2.5,-2)(0.9,0)(0,2)
    \pscurve(0,2)(-0.9,0)(-2.5,-2)
\end{pspicture}

\begin{pspicture}(-3,-2.3)(3,3)
    \pscurve(-2.5,-2)(0,-1.5)(2.5,-2)
    \pscurve(2.5,-2)(0.9,0)(0,2)
    \pscurve(0,2)(-0.9,0)(-2.5,-2)
\end{pspicture}

\end{document}

结果如下：

我想要填充的形状显示在右侧。左侧和中间显示了两次填充形状的不同尝试的结果。不仅两次都不能精确填充形状，而且不匹配还取决于我是否\psclip直接使用\pscustom。这是为什么呢？

Answer 1

在\pscustom 里面最后的直线/曲线（路径）的点是总是这第一的 以下曲线（路径）的点！例如：

      \pscustom{%
        \pscurve(-2.5,-2)(0,-1.5)(2.5,-2)
        \pscurve(2.5,-2)(0.9,0)(0,2)
        ...

错了！第二个\pscurve现在有四对坐标：

        \pscurve(2.5,-2)(2.5,-2)(0.9,0)(0,2)

这与删除第一个点的曲线有很大不同\pscurve(2.5,-2)(0.9,0)(0,2) ，一切都会好起来！

\documentclass[border=3mm]{standalone}
\usepackage{pstricks}
\begin{document}


\begin{pspicture}(-3,-2.3)(3,3)
\psclip[linestyle=none]{%   
    \pscustom{
        \pscurve(-2.5,-2)(0,-1.5)(2.5,-2)
        \pscurve(0.9,0)(0,2)
        \pscurve(-0.9,0)(-2.5,-2)
    }}
    \psframe*[linecolor=gray,opacity=0.6](-3,-3)(3,3)
    \endpsclip
    \pscurve(-2.5,-2)(0,-1.5)(2.5,-2)
    \pscurve(2.5,-2)(0.9,0)(0,2)
    \pscurve(0,2)(-0.9,0)(-2.5,-2)
    \end{pspicture}

    \begin{pspicture}(-3,-2.3)(3,3)
    \pscustom[fillstyle=solid,fillcolor=gray]{
        \pscurve(-2.5,-2)(0,-1.5)(2.5,-2)
        \pscurve(0.9,0)(0,2)
        \pscurve(-0.9,0)(-2.5,-2)
    }
    \pscurve(-2.5,-2)(0,-1.5)(2.5,-2)
    \pscurve(2.5,-2)(0.9,0)(0,2)
    \pscurve(0,2)(-0.9,0)(-2.5,-2)
    \end{pspicture}

    \begin{pspicture}(-3,-2.3)(3,3)
    \pscurve(-2.5,-2)(0,-1.5)(2.5,-2)
    \pscurve(2.5,-2)(0.9,0)(0,2)
    \pscurve(0,2)(-0.9,0)(-2.5,-2)
    \end{pspicture}

\end{document}

以下两条曲线没有区别：

\documentclass[border=3mm]{standalone}
\usepackage{pstricks}
\begin{document}
\begin{pspicture}(-3,-2.3)(3,3)
\pscustom[linewidth=4pt,linecolor=blue]{
    \pscurve(-2.5,-2)(0,-1.5)(2.5,-2)
    \pscurve(0.9,0)(0,2)
    \pscurve(-0.9,0)(-2.5,-2)
    \closepath
}
\psset{linecolor=red,linewidth=1.5pt}
    \pscurve(-2.5,-2)(0,-1.5)(2.5,-2)
    \pscurve(2.5,-2)(0.9,0)(0,2)
    \pscurve(0,2)(-0.9,0)(-2.5,-2)
\end{pspicture}

\end{document}