这是 \psellipticarc 中的错误还是我的计算错误？

Question

这个问题实际上与我昨天发布的另一个问题有联系。

下图说明了这个问题。

简而言之，青色点必须总是与黄色一致。

\documentclass{article}
\usepackage{pstricks-add,multido}

\usepackage[active,tightpage]{preview}
\PreviewEnvironment{pspicture}
\PreviewBorder=0pt


\begin{document}
\multido{\i=0+10}{37}{
\begin{pspicture}(-2.5,-2.0)(2.5,2.0)
        \psframe*[linecolor=black](-2.5,-2.0)(2.5,2.0)
        \pstVerb{/theta \i\space def}%
        \pstVerb{/a 2.25 def}%
        \pstVerb{/b 1.75 def}%
    \ifnum\i=0
        % don't draw arc!
    \else
        \psellipticarc[linecolor=cyan]{-*}(0,0)(!a b){0}{!theta}
    \fi
    \psline[linecolor=yellow]{-*}(0,0)(!theta cos a mul theta sin b mul)
    \uput{5mm}[0](0,0){\color{white}\tiny \i}
\end{pspicture}}
\end{document}

是错误\psellipticarc还是我的计算有误？

Answer 1

\psellipticarc[linecolor=cyan,correctAngle=false]{-*}(0,0)(!a b){0}{!theta}

参见3.4. Macro \psellipticarc​ http://mirror.ctan.org/graphics/pstricks/base/doc/pst-news10.pdf

Answer 2

我刚刚调查过，如果不进行更改correctAngle，false我们仍然可以按如下方式解决此问题。

\documentclass[pstricks,border=0pt]{standalone}
\usepackage{pstricks-add}
\pstVerb
{
    /major 2.25 def
    /minor 1.75 def
    % b a t p2c ---> x y
    % where b (semi-minor), a (semi-major), t (theta)
    /p2c {dup 3 1 roll cos mul 3 1 roll sin mul} bind def
}

\psset{arrows=-*}

\begin{document}
\multido{\i=0+10}{37}
{
    \begin{pspicture}(-2.5,-2.0)(2.5,2.0)
        \ifnum\i=0
            % don't draw arc!
        \else
            \psellipticarc[linecolor=cyan,dimen=middle](!major minor){0}{(!minor major \i\space p2c)}%dimen=middle must be specified!
        \fi
        \psline[linecolor=red](!minor major \i\space p2c)
        \uput{5mm}[!\i\space 10 add](0,0){\tiny$\i^\circ$}
    \end{pspicture}
}
\end{document}