为什么不是棋盘呢？

Question

\documentclass{article} 
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\foreach \x in {1,...,8} 
   \foreach \y in {1,...,8} 
     if (\pgfmathparse{mod(\x+\y,2)==0}) then
       \draw [fill=gray!15] (\x,\y) rectangle (\x+1,\y+1);

\draw [line width=.5mm] (1,1) -- (9,1) -- (9,9) -- (1,9) -- (1,1);
       
\foreach \x in {1,...,8}
  \foreach \y in {1,...,2}
     \draw [fill=red!50](\x+0.5,\y+0.5) circle (0.4cm);

\foreach \x in {1,...,8}
  \foreach \y in {7,...,8}
     \draw [fill=blue!50](\x+0.5,\y+0.5) circle (0.4cm);
\end{tikzpicture}
\end{document}

Answer 1

我宁愿做以下事情：

\documentclass[border=10pt]{standalone} 
\usepackage{tikz}
\begin{document}
    \begin{tikzpicture}
    \foreach \x in {1,...,8} {
        \foreach \y [evaluate=\y as \z using {int(mod(\x+\y,2))}] in {1,...,8} {
            \ifnum\z=0\relax
                \draw[fill=gray!15] (\x,\y) rectangle (\x+1,\y+1);
            \fi
        }
    }
    
    \draw[line width=.5mm] (1,1) rectangle (9,9);
           
    \foreach \x in {1,...,8}
        \foreach \y in {1,2}
            \draw[fill=red!50] (\x+0.5,\y+0.5) circle[radius=0.4];
    
    \foreach \x in {1,...,8}
        \foreach \y in {7,8}
            \draw[fill=blue!50] (\x+0.5,\y+0.5) circle[radius=0.4];
    \end{tikzpicture}
\end{document}

但实际上，你并不需要任何 if-else 语句：

\documentclass[border=10pt]{standalone} 
\usepackage{tikz}
\begin{document}
    \begin{tikzpicture}
    \foreach \x in {1,3,...,7} 
        \foreach \y in {1,...,8} 
            \draw[fill=gray!15] ({\x+mod(\x+\y,2)},\y) rectangle ++(1,1);
    
    \draw[line width=.5mm] (1,1) rectangle (9,9);
           
    \foreach \x in {1,...,8}
        \foreach \y in {1,2}
            \draw[fill=red!50] (\x+0.5,\y+0.5) circle[radius=0.4];
    
    \foreach \x in {1,...,8}
        \foreach \y in {7,8}
            \draw[fill=blue!50] (\x+0.5,\y+0.5) circle[radius=0.4];
    \end{tikzpicture}
\end{document}

Answer 2

如果你想要按照你的模板进行实施，你可以\tikzmath使用如何在\foreachTikZ 中跳过某个值？

\documentclass[tikz]{standalone}
\usetikzlibrary{math}
\begin{document}
\begin{tikzpicture}[radius=.4]
\tikzmath{
  for \x in {1, ..., 8}{
    for \y in {1, ..., 8} {
      if mod(\x+\y,2)==0 then {
        { \draw [fill=gray!15] (\x, \y) rectangle +(1, 1); };
      };
    };
  };
}

\draw [line width=.5mm] (1,1) rectangle (9,9);

\foreach \x in {1, ..., 8}
  \foreach \y in {1, 2}{
    \draw [fill=red!50]  (\x+0.5,   \y+0.5) circle[];
    \draw [fill=blue!50] (\x+0.5, 9-\y+0.5) circle[];
  }
\end{tikzpicture}
\end{document}

但是，我们不必经历所有这些，\x我们可以从一开始就跳过每一秒：

\documentclass[tikz]{standalone}
\begin{document}
\begin{tikzpicture}[radius=.4]
\foreach \x in {1, ..., 4}
  \foreach \y in {1, ..., 8}
    \draw[shift=(right:iseven \y), fill=gray!15] (2*\x-1, \y) rectangle +(1, 1);

\draw [line width=.5mm] (1,1) rectangle (9,9);

\foreach \x in {1, ..., 8}
  \foreach \y in {1, 2}{
    \draw [fill=red!50]  (\x+0.5,   \y+0.5) circle[];
    \draw [fill=blue!50] (\x+0.5, 9-\y+0.5) circle[];
  }
\end{tikzpicture}
\end{document}

我还擅自使用了radius = .4而不是.4cm来避免混合坐标和画布坐标系。

Answer 3

使用（{NiceArray}您nicematrix需要多次编译）。

\documentclass{article} 
\usepackage{nicematrix,tikz}

\begin{document}

\NewDocumentCommand{\Blue}{}
  {\tikz [baseline] \draw [fill=blue!50] circle (0.4cm) ; }

\NewDocumentCommand{\Red}{}
  {\tikz [baseline] \draw [fill=red!50] circle (0.4cm) ; }

$\begin{NiceArray}{>{\rule[-16pt]{0pt}{32pt}}cccccccc}[hvlines,rounded-corners]
\CodeBefore
  \chessboardcolors{gray!10}{}
\Body
  \Blue & \Blue & \Blue & \Blue & \Blue & \Blue & \Blue & \Blue \\
  \Blue & \Blue & \Blue & \Blue & \Blue & \Blue & \Blue & \Blue \\
  \\
  \\
  \\
  \\
  \Red & \Red & \Red & \Red & \Red & \Red & \Red & \Red \\
  \Red & \Red & \Red & \Red & \Red & \Red & \Red & \Red \\
\end{NiceArray}$

\end{document}