TikZ 的“分隔线”

Question

我想用 TikZ 画出我的论文结构。在 Paint 中画出草图：

到目前为止，节点都很简单，但我找不到一个好的带有标签的分界线的解决方案。例如，我设法将一个名为“Preliminaries”的节点放置在“Introduction”节点上方，并在左侧任意距离放置，使用let来自的解决方案这个问题，并想到用它的西北锚点画一条线。但我不知道如何确保这条线至少和图片一样宽（由章节节点最宽行的宽度决定），也不知道如何计算这条线的端点，以便它从第一个章节节点的中心向左和向右延伸相同的距离。

如何获取节点之间的水平分隔线，延伸至图形的整个宽度？

    \documentclass{article}

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

\begin{document}

\begin{figure}
\centering

\begin{tikzpicture}[
  chapter/.style={
    rectangle, 
    minimum width=8mm, 
    minimum height=3mm,
    rounded corners=1mm, 
    align=center,
    draw
  },
  font=\sffamily
]
 \node [chapter](introduction){
 \textbf{Introduction} \\
 Motivation, goals and contribution 
 };
  \node [chapter, below=4mm of introduction.south](background){
 \textbf{Background} \\
 Context and terms 
 };

 % This tries to make ``Preliminaries'' a node, but maybe this is not the best approach anyway
 %\draw ($(introduction.north west)+(-1,0.5)$) -- ($(introduction.north east)+(1,0.5)$);
 %\path let \p1 = (introduction.north) in node (preliminaries) at (-5, \y1+10)  {
 % Preliminaries
 %};
\end{tikzpicture}

 \caption{Structure of the thesis}
 \label{fig:structure-of-the-thesis}
\end{figure}

\end{document}

Answer 1

像这样？

我在上面的图片中考虑你的（相当简单的）图像：

\documentclass{article}
\usepackage[showframe,% only for test page layout
            margin=30mm]{geometry}
\usepackage{tikz}
 \usetikzlibrary{positioning, calc, shadows}

\begin{document}
    \begin{figure}%[ht]
\centering
    \begin{tikzpicture}[
    node distance = 7mm and 4mm,
every node/.style = {font=\bfseries\itshape},
   chapter/.style = {rectangle, draw, semithick, rounded corners,
                     text width=44mm, minimum height=11mm, align=center,
                     fill=white, drop shadow},  
        ys/.style = {yshift=-7mm}         
                        ]
\draw[thick] (0,0)  coordinate (A1)
                    node[below right] {Preliminaries} 
                    -- + (\textwidth,0)
                    coordinate (B1);
\node (ch1) [chapter, below=of $(A1)!0.5!(B1)$]         {Introduction};
\node (ch2) [chapter, below=of ch1]                     {Background};
\draw[thick] ([ys] A1 |- ch2.south)  coordinate (A2)
                    node[below right] {Problem states}
                    -- + (\textwidth,0)
                    coordinate (B2);
\node (ch3) [chapter, below  left=of $(A2)!0.5!(B2)$]   {State of the Art};
\node (ch4) [chapter, below right=of $(A2)!0.5!(B2)$]   {Building of Theory};
\draw[thick] ([ys] A1 |- ch3.south)  coordinate (A3)
                    node[below right] {Solution}
                    -- + (\textwidth,0)
                    coordinate (B3);
\node (ch5) [chapter, below=of $(A3)!0.5!(B3)$]         {My New Theory};
\node (ch6) [chapter, below=of ch5]                     {Validation of the Method};
\draw[thick] ([ys] A1 |- ch6.south)  coordinate (A4)
                    node[below right] {Conclusion}
                    -- + (\textwidth,0)
                    coordinate (B4);
\node (ch7) [chapter, below=of $(A4)!0.5!(B4)$]         {Discussion and conclusions};
\node (ap1) [chapter, below  left=of ch7]               {Appendix A};
\node (ap2) [chapter, below =of ch7]                    {Appendix B};
\node (ap3) [chapter, below right=of ch7]               {Appendix C};
\end{tikzpicture}
    \caption{Structure of the thesis}
\label{fig:structure-of-the-thesis}
    \end{figure}
\end{document}

Answer 2

如果您首先绘制所有框，则可以用来current bounding box获取图形的左边框和右边框。

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{positioning}
\usetikzlibrary{calc}
\begin{document}
\begin{tikzpicture}[
  TestBox/.style={draw,minimum width=3cm,minimum height=3em,rounded corners=2mm}]
  \node[TestBox] (A) {A};
  \node[TestBox,below left= of A](B){B};
  \node[TestBox,below right= of A](C){C is a bit longer than the other boxes};
  \node[TestBox,below=of $(B.south east)!0.5!(C.south west)$](D) {D};
  \node[TestBox,below=of D](E) {E};
  %%
  \coordinate(BBw) at ($(current bounding box.west)+(-5mm,0)$);
  \coordinate(BBe) at ($(current bounding box.east)+(5mm,0)$);
  \coordinate(Level1) at ($(C.south)!0.5!(D.north)$);
  \draw (Level1 -| BBw) -- (Level1-|BBe) node[pos=0,anchor=north west]{Label of line};
\end{tikzpicture}
\end{document}