或者不使用绘图函数,通过使用arc
:
\documentclass[tikz,
border=1mm,
preview]{standalone}
\begin{document}
\begin{tikzpicture}
\fill[gray!10] ( -3,-3) |- (-0.4,0) arc (-180:0:4mm) -| (3,-3);
\draw ( -3,0) -- (-0.4,0) (0.4,0) -- ( 3.0,0);
\draw [blue,thick] (-0.4,0) arc (-180:0:4mm);
\end{tikzpicture}
\end{document}