在 Tikz 中将节点放置在可见网格上

Question

我试图将两个节点放置在网格上的特定点附近，这看起来很简单但是当我尝试时：

\documentclass{article}
\usepackage{tikz}
\begin{document}
 \usetikzlibrary{calc}
 \begin{tikzpicture}[scale=1.5]
  \tikzset{microphone/.style={black,circle,draw,fill=gray,pos=0.75,scale=0.5,inner sep=2pt}};

  \coordinate (centre_of_array) at (4,1);
  \coordinate (bottom_left) at (0,0);
  \coordinate (top_right) at (7,5);
  \draw [dotted, draw=black, fill=white] (bottom_left) grid  (top_right);
  \draw [ultra thick, draw=black] (bottom_left) rectangle  (top_right);
  \node[microphone, label=below:$x_1$, left of=centre_of_array] (x1) {};
  \node[microphone, label=below:$x_2$,right of=centre_of_array] (x2) {};
 \end{tikzpicture}
\end{document} 

我得到以下信息：

这看起来很简单，但在这里搜索后，我找不到任何人发布过类似的内容，为什么“麦克风”没有放在网格上位置 (4,1) 的两侧？我遗漏了什么吗？

非常感谢。

Answer 1

你已经在你的microphone风格中定义了一个位置。如果你把它去掉，你就会得到你想要的。

% arara: pdflatex

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{calc, positioning}

\begin{document}        
    \begin{tikzpicture}[scale=1.5]
    \tikzset{microphone/.style={black,circle,draw,fill=gray,scale=0.5,inner sep=2pt}};

    \coordinate (centre_of_array) at (4,1);
    \coordinate (bottom_left) at (0,0);
    \coordinate (top_right) at (7,5);
    \draw [dotted, draw=black, fill=white] (bottom_left) grid  (top_right);
    \draw [ultra thick, draw=black] (bottom_left) rectangle  (top_right);
    \node[microphone, label=below:$x_1$, left = of centre_of_array] (x1) {};
    \node[microphone, label=below:$x_2$, right = of centre_of_array] (x2) {};
    \end{tikzpicture}
\end{document}