我怎样才能为形状添加阴影？

Question

我正在尝试解决寻找 A 赞美的问题，为此我需要遮蔽 A 圈之外的所有内容。但是，我遇到了很多麻烦，如果有人可以告诉我如何做或指出正确的方向，我将不胜感激：

\documentclass[12pt]{article}

\usepackage{graphicx}
\usepackage{fullpage}
\usepackage{tikz} 

\def \setA { (-11,-5) circle (1cm) }
\def \setB { (-9.5,-5) circle (1cm) }
\def \setC { (-12 ,-8) circle (1cm) }
\def \rectangle { (-15,-10) rectangle (-5,-3) } 

\begin{document}

        \title{ \bfseries Statistics and Probability for Engineers \\ Assignment \#1 }

        \maketitle

        \begin{enumerate}

            \item   
                \begin{enumerate}

                \item 

                    \begin{tikzpicture}
                    \draw \rectangle ;
                    \draw \setA node[below left] {$A$};
                    \draw \setB node[below left] {$B$};
                    \draw \setC node[below left] {$C$};

                    \clip \setB
                    \clip \setC

                    \fill[gray] \rectangle

                    \end{tikzpicture}





                \end{enumerate}

        \end{enumerate}


\end{document}

Answer 1

可能是這樣嗎？

\documentclass[12pt]{article}
\usepackage{tikz}

\def \setA { (-11,-5) circle (1cm) }
\def \setB { (-9.5,-5) circle (1cm) }
\def \setC { (-12 ,-8) circle (1cm) }
\def \rectangle { (-15,-10) rectangle (-5,-3) }

\begin{document}
   \begin{tikzpicture}
   \draw[fill=olive!20] \rectangle ;
   \fill[white] \setA;
   \draw[fill=olive!20] \setB node[below left] {$B$};
   \draw \setA node[below left] {$A$};
   \draw \setC node[below left] {$C$};
   \end{tikzpicture}

\end{document}

要填充交叉点，您可以使用\clip：

\documentclass[12pt]{article}
\usepackage{tikz}

\def \setA { (-11,-5) circle (1cm) }
\def \setB { (-9.5,-5) circle (1cm) }
\def \setC { (-12 ,-8) circle (1cm) }
\def \rectangle { (-15,-10) rectangle (-5,-3) }

\begin{document}
   \begin{tikzpicture}
   \draw \rectangle ;
   \draw \setA node[below left] {$A$}
   \setB node[below left] {$B$};
   \draw \setC node[below left] {$C$};
   \clip \setB;
   \fill[olive] \setA;
   \end{tikzpicture}

\end{document}