描述

Question

描述

这个问题源于为什么装饰标记偏离中心？我们发现问题所在，但没有为什么这是首先发生的。

似乎在放置物体时o2 多于图片o1选项above被传递给物体中的装饰o2。这是假设，因为当我们放置物体时o2_2 在位于上方的节点o1_2，则装饰将按预期绘制。

示例图像

半最小代码

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{shapes,positioning,fit,decorations.markings,patterns}

\pagenumbering{gobble} % remove page numbering to get good cropping when using pdfcrop

\def\pnode [#1]#2{
    % node for the potential function
    \node[regular polygon,regular polygon sides=4, minimum size=5.0pt,fill=black,#1] (#2) {};
}
\def\snode [#1]#2#3{
    % node for the state variables
    \node[circle, minimum size=35.0pt , fill=lightgray,line width=0.625pt, draw=black,#1](#3){#2};
}
\def\osnode [#1]#2#3{
    % for for observed state variables
    \node[circle, minimum size=35.0pt , fill={rgb:red,1;green,2;blue,3},line width=0.625pt, draw=black,#1](#3){#2};
}
\tikzset{
    set midblock/.code={\pgfqkeys{/tikz/midblock}{#1}},
    set midblock={name/.initial=b1},
    midblock/.style={
        set midblock={#1},
        postaction={
            decorate,
            decoration={
                markings,
                mark=at position .5 with {\pnode[]{\pgfkeysvalueof{/tikz/midblock/name}}}}
        }
    }
}

\tikzset{
    pics/object1/.style 2 args={
       code={
        \begin{scope}
            \snode[]{obj-1}{-i};
        \end{scope}
        }
    }
}

\tikzset{
    pics/object2/.style 2 args={
       code={
        \begin{scope}[rotate=#2, transform shape]
            \snode[]{obj-2}{-i};
            \snode[right = of -i]{j-txt}{-j};
            \snode[above = of -i]{k-txt}{-k};
            \snode[left = of -i]{l-txt}{-l};
            \draw[midblock={name=foo}] (-i)--(-j);
            \draw[midblock={name=baz}] (-j)--(-k);
            \draw[midblock={name=bar}] (-k)--(-l);
            \draw[midblock={name=bar}] (-l)--(-i);
        \end{scope}
        }
    }
}

\begin{document}

\begin{tikzpicture}
    % Broken Code ...  but why?
    \path pic (o1) {object1};
    \pic [above= of o1-i] (o2) {object2={}{0}};
\end{tikzpicture}
\hspace {2cm}
\begin{tikzpicture}
    % This code works
    \path pic (o1_2) {object1};
    \snode[above=of o1_2-i]{}{n1};
    \pic (o2_2) at (n1) {object2={}{0}};
\end{tikzpicture}

\end{document}

******编辑******

根据要求提供一个更简约的例子。

图像

代码

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{shapes,positioning,fit,decorations.markings,patterns}

\pagenumbering{gobble} % remove page numbering to get good cropping when using pdfcrop

\def\pnode [#1]#2{
    % node for the potential function
    \node[regular polygon,regular polygon sides=4, minimum size=5.0pt,fill=black,#1] (#2) {};
}
\def\snode [#1]#2#3{
    % node for the state variables
    \node[circle, minimum size=35.0pt , fill=lightgray,line width=0.625pt, draw=black,#1](#3){#2};
}

\tikzset{
    set midblock/.code={\pgfqkeys{/tikz/midblock}{#1}},
    set midblock={name/.initial=b1},
    midblock/.style={
        set midblock={#1},
        postaction={
            decorate,
            decoration={
                markings,
                mark=at position .5 with {\pnode[]{\pgfkeysvalueof{/tikz/midblock/name}}}}
        }
    }
}

\tikzset{
    pics/object1/.style 2 args={
       code={
        \begin{scope}
            \snode[]{obj-1}{-i};
        \end{scope}
        }
    }
}

\tikzset{
    pics/object2/.style 2 args={
       code={
        \begin{scope}[rotate=#2, transform shape]
            \snode[]{obj-2}{-i};
            \snode[right = of -i]{j-txt}{-j};
            \draw[midblock={name=foo}] (-i)--(-j);
        \end{scope}
        }
    }
}

\begin{document}

\begin{tikzpicture}
    % Broken Code ...  but why?
    \path pic (o1) {object1};
    \pic [above= of o1-i] (o2) {object2={}{0}};
\end{tikzpicture}
\hspace {2cm}
\begin{tikzpicture}
    % This code works
    \path pic (o1_2) {object1};
    \snode[above=of o1_2-i]{}{n1};
    \pic (o2_2) at (n1) {object2={}{0}};
\end{tikzpicture}

\end{document}

Answer 1

\pic[above= of o1-i]...
→ \path pic[above= of o1-i]...
→ node[above= of o1-i]...
→ \tikzset{above= of o1-i}
→\def\tikz@anchor{south}

记住这一点，你的问题可以通过为 指定显式锚点来解决\pnode。也就是说，你只需要替换

\pnode[]

经过

\pnode[anchor=center]

一切按预期进行。