Tikz，将常用参数保存到变量中

Question

我必须绘制多个像这样的节点：

\node[circle, minimum size=2cm] (P0) at (0,0) {$1$};
\node[circle, minimum size=2cm, fill=red] (P1) at (1,0) {$2$};
\node[circle, minimum size=2cm, fill=black] (P2) at (2,0) {$3$};

但每次我有共同的圆和最小尺寸时，我都会尝试做这样的事情：

\newcommand{\NodeClassic}{circle, minimum size=2cm}
\newcommand{\NodeRed}{circle, minimum size=2cm, fill=red}
\newcommand{\NodeBlack}{circle, minimum size=2cm, fill=black}

之后 ：

\node[\NodeClassic] (P0) at (0,0) {$1$};
\node[\NodeRed] (P1) at (1,0) {$2$};
\node[\NodeBlack] (P2) at (2,0) {$3$};

像这样，我可以添加一些参数：

\node[\NodeClassic, yellow] (P0) at (0,0) {$1$};

我的文件：

\documentclass[14pt]{article}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage[utf8]{inputenc}

\usepackage{tikz}

\newcommand{\NodeClassic}{circle, minimum size=2cm}
\newcommand{\NodeRed}{circle, minimum size=2cm, fill=red}
\newcommand{\NodeBlack}{circle, minimum size=2cm, fill=black}

\begin{document}

\begin{tikzpicture}
    \node[\NodeClassic] (P0) at (0,0) {$1$};
    \node[\NodeRed] (P1) at (1,0) {$2$};
    \node[\NodeBlack] (P2) at (2,0) {$3$};
\end{tikzpicture}

\end{document}

Overleaf 上的错误消息：

 Package pgfkeys Error: I do not know the key '/tikz/circle, minimum size=2cm, fill=red' and I am going to ignore it. Perhaps you misspelled it.

See the pgfkeys package documentation for explanation.
Type  H <return>  for immediate help.
 ...                                              
                                                  
l.16     \node[\NodeRed]
                         (P1) at (1,0) {$2$};

我已经在 \newcommand 中尝试了 \def\command{params} 或 \tikz{params} 谢谢，

Answer 1

您应该使用样式：

\documentclass{article}

\usepackage{tikz}

\tikzset{
  NodeClassic/.style={draw,circle, minimum size=2cm},
  NodeRed/.style={circle, minimum size=2cm, fill=red},
  NodeBlack/.style={circle, minimum size=2cm, fill=black!20},
}

\begin{document}

\begin{tikzpicture}
    \node[NodeClassic] (P0) at (0,0) {$1$};
    \node[NodeRed] (P1) at (2,0) {$2$};
    \node[NodeBlack] (P2) at (4,0) {$3$};
\end{tikzpicture}

\end{document}

我改变了选项以绘制白色圆圈并减少黑色节点中的黑色，只是为了看到节点内容。

没有14pt选项article。

Answer 2

您要查找的变量称为“样式”。样式也可以有参数。例如，

  mynode/.style={circle,minimum size=2cm,fill=#1},
  mynode/.default={white}

定义一个mynode带有一个参数（填充颜色）的样式。其默认值为white。

\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}[
  mynode/.style={circle,minimum size=2cm,fill=#1},
  mynode/.default={white}
  ]
  \node[mynode] (P0) at (0,0) {$1$};
  \node[mynode=red] (P1) at (1,0) {$2$};
  \node[mynode=black] (P2) at (2,0) {$3$};
\end{tikzpicture}
\end{document}