版本 1（速度减慢）

Question

\documentclass[pstricks,border=15pt,12pt]{standalone}
\usepackage{pst-node,multido}

\begin{document}
\multido{\n=0+1, \i=90+-1}{91}{%
\begin{pspicture}[showgrid=true](5,5)
\psarc{->}(0,0){1}{0}{\n}
\psarc{->}(0,0){2}{0}{\n}
\psarcn{->}(0,0){4}{90}{\i}
\psarcn{->}(0,0){5}{90}{\i}
\end{pspicture}}
\end{document}

\documentclass[pstricks,border=15pt,12pt]{standalone}
\usepackage{pst-node,multido}

\begin{document}
\multido{\n=0+1,\i=90+-1}{46}{%
\begin{pspicture}[showgrid=true](5,5)
\psarc{->}(0,0){3}{0}{\n}
\psarcn{->}(0,0){3}{90}{\i}
\end{pspicture}}
\end{document}

问题：

如何通过一个循环将上面的两个动画结合起来？

Answer 1

\documentclass[pstricks,border=15pt,12pt]{standalone}
\usepackage{pst-node,multido}

\begin{document}
\multido{\in=0+1,\i=90+-1}{91}{%
  \begin{pspicture}[showgrid=true](5,5)
  \psarc{->}(0,0){1}{0}{\in}
  \psarc{->}(0,0){2}{0}{\in}
  \psarcn{->}(0,0){4}{90}{\i}
  \psarcn{->}(0,0){5}{90}{\i}
  \ifnum\in>45
    \def\nn{45}
    \def\ii{45}
  \else
    \edef\nn{\in}
    \edef\ii{\i}
  \fi
  \psarc{->}(0,0){3}{0}{\nn}
  \psarcn{->}(0,0){3}{90}{\ii}
  \end{pspicture}%
}
\end{document}

Answer 2

这只是另一个想法。

版本 1（速度减慢）

\documentclass[pstricks,border=15pt]{standalone}
\usepackage{multido}

\begin{document}
\multido{\ia=0+1,\ib=90+-1}{91}{%
  \begin{pspicture}[showgrid=true,arrows=->,arrowinset=0](5,5)
  \psarc(0,0){1}{0}{\ia}
  \psarc(0,0){2}{0}{\ia}
  \psarcn(0,0){4}{90}{\ib}
  \psarcn(0,0){5}{90}{\ib}
  \psarc(0,0){3}{0}{!\ia\space 2 div}
  \psarcn(0,0){3}{90}{!45 \ib\space 2 div add}
  \end{pspicture}}
\end{document}

版本 2（重新发布）

\documentclass[pstricks,border=15pt]{standalone}
\usepackage{multido}

\begin{document}
\multido{\ia=0+1,\ib=90+-1}{91}{%
  \begin{pspicture}[showgrid=true,arrowinset=0,arrows=->](5,5)
  \psarc(0,0){1}{0}{\ia}
  \psarc(0,0){2}{0}{\ia}
  \psarcn(0,0){4}{90}{\ib}
  \psarcn(0,0){5}{90}{\ib}
  \psarc(0,0){3}{0}{!\ia\space 45 gt {\ia\space 45 sub} {\ia} ifelse}
  \psarcn(0,0){3}{90}{!\ib\space 45 lt {\ib\space 45 add} {\ib} ifelse}
  \end{pspicture}}
\end{document}