是否可以使用 \only 有条件地启用宏的键值对？

Question

以下是一个简单的例子。我想学习如何使用\only<>（如果可能）有条件地启用宏的键值对。

\documentclass{beamer}
\usepackage{pstricks}

\usepackage[active,tightpage]{preview}
\PreviewEnvironment{pspicture}
\PreviewBorder=12pt\relax

\makeatletter
\let\Test@pr@shipout\pr@shipout%% save the original definition
\let\Test@shipout\shipout
\AtBeginDocument{%
  \let\pr@shipout\Test@pr@shipout%% restore it 
  \let\shipout\Test@shipout
}
\makeatother


\def\RightPart{
    % start from ear to tail
    \only<+->{\moveto(.5,2.7)}
    \only<+->{\psline(1,3.25)}
    \only<+->{\psbezier(1.2,1.3)(1.3,1)(2,1)}
    \only<+->{\psbezier(3,1)(3,2.2)(!3.3 6 72 p2c)}
    \only<+->{\psellipticarcn(6,3.3){(!3.3 6 72 p2c)}{(!3.3 6 72 neg p2c)}}
    \only<+->{\psbezier(4,-2)(4,0)(2.2,-1.8)}
    \only<+->{\psbezier(1.5,-1)(1,-1)(0,-3.2)}
}

\def\LeftPart{
    % start from tail to ear
        \only<+->{\psbezier(1,-1)(1.5,-1)(2.2,-1.8)}
        \only<+->{\psbezier(4,0)(4,-2)(!3.3 6 72 neg p2c)}
        \only<+->{\psellipticarc(6,3.3){(!3.3 6 72 neg p2c)}{(!3.3 6 72 p2c)}}  
        \only<+->{\psbezier(3,2.2)(3,1)(2,1)}    
        \only<+->{\psbezier(1.3,1)(1.2,1.3)(1,3.25)}
        \only<+->{\psline(.5,2.7)}      
        \only<+->{\closepath}
}

\begin{document}
\begin{frame}
\begin{pspicture}[dimen=m](-6,-3)(6,3)  
    \pstVerb{/p2c {dup 3 1 roll cos mul 3 1 roll sin mul} bind def}
    %\pscustom[\only<15->{fillstyle=solid,fillcolor=yellow}]
    \pscustom[fillstyle=solid,fillcolor=yellow]
    {
        \RightPart
        \code{-1 1 scale}
        \LeftPart
    }
\end{pspicture}
\end{frame}
\end{document}

那么我该如何使用才能\pscustom[\only<15->{fillstyle=solid,fillcolor=yellow}]让我最后填充封闭区域？请不要建议我使用，psclip因为这不是我想要学习的。

Answer 1

您可以使用可以包装的选项，而不必fillstyle直接提供选项。因此，代码中的相关更改是：\pscustom\fill[fillstyle=solid, fillcolor=yellow]\only

\pscustom{
    \RightPart
    \code{-1 1 scale}
    \LeftPart
    \only<+->{\fill[fillstyle=solid, fillcolor=yellow]}
}