设置一个 tikzset，里面有 draw 样式，就像 \node 一样

Question

我需要为我的矩形节点获取不同颜色的边缘。

我发现这个问题 如何仅设置 tikz 节点的边框颜色的一侧？

答案中提到的 \tikzset 有输入参数，我不知道在与 \node 一起使用时如何设置它们。

我试图删除参数并设置样式，但我得到的只是一个无限循环的 xetex。

\documentclass{article}
\usepackage{tikz}
\usepackage{pgfplots}
\tikzset{%
mynode/.style ={
       \draw[thick,red,line cap=butt,shorten <= -0.5\pgflinewidth,shorten >= 0.5\pgflinewidth] (a.south west) |- (a.north east);
       \draw[thick,blue,line cap=butt,shorten <= 0.5\pgflinewidth,shorten >= -0.5\pgflinewidth] (a.south west) -| (a.north east);

}
}
\begin{document}
\begin{figure}[ht]
\begin{center}
\begin{tikzpicture}
\tikzstyle{main}=[rectangle, minimum width = 30mm,minimum height = 50mm, thick, draw =black!80, node distance = 6mm]

    \node[main] (m)  {$A$ };
    \node[mynode] [right=of m] (x2) { $R$}; %commenting this line out with eliminate the infinite loop
\end{tikzpicture}
\end{center}
\end{figure}
\end{document}

提前致谢

Answer 1

如果你正在寻找这样的东西

以下 MWE 可能会有所帮助：

\documentclass[tikz,border=3mm]{standalone}
\newcommand\ppbb{path picture bounding box}
\tikzset{%
    mynode/.style = {rectangle, 
    path picture={%
    \draw[thick,red]    (\ppbb.south west) |- (\ppbb.north east);
    \draw[thick,blue]   (\ppbb.south west) -| (\ppbb.north east);
                },% end of path picture
                 },
        }% end of tikzset
\begin{document}
    \begin{tikzpicture}
\node (x2) [mynode] {$R$};    
    \end{tikzpicture}
\end{document}

编辑： 或外观略​​有不同

使用以下代码（略作修改）获得：

\documentclass[tikz,border=3mm]{standalone}
\newcommand\ppbb{path picture bounding box}
\tikzset{%
    myline/.style={draw=#1, thick, shorten <=0.5\pgflinewidth},
    mynode/.style = {rectangle, 
    path picture={%
    \draw[myline=red]    (\ppbb.south west) |- (\ppbb.north east);
    \draw[myline=blue]   (\ppbb.north east) |- (\ppbb.south west);
                },% end of path picture
                 },
        }% end of tikzset
\begin{document}
    \begin{tikzpicture}
\node (x2) [mynode] {$R$};    
    \end{tikzpicture}
\end{document}