如何在“箭头”下方或上方书写？

Question

我制作了这个文件，请教如何在“箭头”下面和上面写字

\documentclass[12pt]{report}
\usepackage{tikz}
\usetikzlibrary{arrows}
\usetikzlibrary{decorations.markings}
\linespread{1.5} 
\textwidth=16truecm \textheight=23truecm  \voffset=-1truecm
\hoffset=-1 truecm \thispagestyle{empty}

\begin{document}
\begin{tikzpicture}[node distance=2cm]  

\node (A) at (0,4) {$1$};
\node (B) at (   4,2) {$2$};
\node (C) at (  4,-1) {$3$};
\node (D) at (-4,-1) {$4$};
\node (E) at (-4,2) {$5$};


  \draw[
        decoration={markings, mark=at position 0.625 with {\arrow{>}}},
        postaction={decorate}
        ]
        (0,4) circle (0.4);
    \draw[ 
        decoration={markings, mark=at position 0.125 with {\arrow{>}}},
        postaction={decorate}
        ]
        (4,2) circle (0.4);

  \draw[ 
        decoration={markings, mark=at position 0.125 with {\arrow{>}}},
        postaction={decorate}
        ]
        (4,-1) circle (0.4);
        \draw[ 
        decoration={markings, mark=at position 0.125 with {\arrow{>}}},
        postaction={decorate}
        ]
        (-4,-1) circle (0.4);
        \draw[ 
        decoration={markings, mark=at position 0.125 with {\arrow{>}}},
        postaction={decorate}
        ]
        (-4,2) circle (0.4);
    % draw the connecting line
    \draw[ 
        decoration={markings, mark=at position 0.5 with {\arrow{>}}},
        postaction={decorate}
        ]
          (0,3.6)--(3.6,1.9) ;
          \draw[ 
        decoration={markings, mark=at position 0.5 with {\arrow{>}}},
        postaction={decorate}
        ]
          (3.6,1.9)--(3.6,-1);
          \draw[ 
        decoration={markings, mark=at position 0.5 with {\arrow{>}}},
        postaction={decorate}
        ]
          (3.6,-1)--(-3.6,-1);
           \draw[ 
        decoration={markings, mark=at position 0.5 with {\arrow{>}}},
        postaction={decorate}
        ]
          (-3.6,-1)--(-3.6,2);
          \draw[ 
        decoration={markings, mark=at position 0.5 with {\arrow{>}}},
        postaction={decorate}
        ]
       (0,3.6) -- (-3.6,2);
           \draw[ 
        decoration={markings, mark=at position 0.5 with {\arrow{>}}},
        postaction={decorate}
        ]
          (0,3.6)--(-3.6,-1);
           \draw[ 
        decoration={markings, mark=at position 0.5 with {\arrow{>}}},
        postaction={decorate}
        ]
          (0,3.6)--(3.6,-1);
            \draw[ 
        decoration={markings, mark=at position 0.5 with {\arrow{>}}},
        postaction={decorate}
        ]
          (3.6,-1)--(-3.6,2);
           \draw[ 
        decoration={markings, mark=at position 0.5 with {\arrow{>}}},
        postaction={decorate}
        ]
          (3.6,1.9)--(-3.6,-1);

    % draw the two black dots
    \fill (0,3.6) circle (0.1); 
    \fill (3.6,1.9) circle (0.1); 
    \fill (3.6,-1) circle (0.1); 
    \fill (-3.6,-1) circle (0.1); 
     \fill (-3.6,2) circle (0.1); 
    \end{tikzpicture}


\end{document}

Answer 1

起点：

\documentclass[tikz, margin=3mm]{standalone}
\usetikzlibrary{arrows, calc, decorations.markings, positioning, quotes}

\begin{document}
    \begin{tikzpicture}[
node distance = 20mm and 30mm,
     C/.style = {circle, draw=red, inner sep=0pt, outer sep=0pt, minimum size=8mm,
                 },
   dot/.style = {circle, fill, inner sep=0pt, minimum size=2mm,
                 node contents={}},
     L/.style = {decoration={markings, mark=at position 0.4 with {\arrow{>}}},
                 postaction={decorate}},
every edge quotes/.append style = {anchor=north, sloped, font=\footnotesize},
every edge/.append style = {L}
                 ]
% main nodes
\node (A) [dot];
\node (B) [dot,below right=of A];%  {2};
\node (C) [dot,below=of B];%        {3};
\node (E) [dot,below  left=of A];%  {5};
\node (D) [dot,below=of E];%        {4};
% dots
\draw[L]    ($(A)+(0, 5mm)$) circle (5mm) node {1};
\draw[L]    ($(B)+( 5mm,0)$) circle (5mm) node {2};
\draw[L]    ($(C)+( 5mm,0)$) circle (5mm) node {3};
\draw[L]    ($(D)+(-5mm,0)$) circle (5mm) node {4};
\draw[L]    ($(E)+(-5mm,0)$) circle (5mm) node {5};
% draw the connecting line
\path   (A) edge ["some text"]    (B)
        (B) edge ["some text"]    (C)
        (C) edge ["some text"]    (D)
        (D) edge ["some text"]    (E)
        (E) edge ["some text"]    (A)
%
        (E) edge [pos=0.3, "some text"] (C)
        (D) edge [pos=0.3, "{$H(\{1\},\{2\})=\frac{1}{5}$}"] (B)
        ;
    \end{tikzpicture}
\end{document}

图像尚未完成，甚至对于正确的箭头方向我也不确定。这很容易完成，并且通过坐标交换很容易实现。

对于路径上的文本，我使用quotes库。它的语法很简单：

 \draw (<coordinate 1>) edge ["text"] (coordinate 2);

为了出现在箭头的所需一侧、具有所需的字体大小等，我添加了边缘样式选项：

every edge quotes/.append style = {anchor=north, sloped, font=\footnotesize}

您还可以看到，我使用库positioningod 定义的相对定位来绘制节点的边名dot。所有这些，。一起到路径装饰的通用样式，我定义了样式L。

Answer 2

边缘标签用引号表示，当它们随着边缘倾斜时，其上下定位并不简单，因此需要新的答案。作为（粗鲁的）解决方案，使用节点如下：

\documentclass[tikz, margin=3mm]{standalone}
\usetikzlibrary{arrows, calc, decorations.markings, positioning, quotes}

\begin{document}
    \begin{tikzpicture}[
node distance = 20mm and 30mm,
     C/.style = {circle, draw=red, inner sep=0pt, outer sep=0pt, minimum size=8mm,
                 },
   dot/.style = {circle, fill, inner sep=0pt, minimum size=2mm,
                 node contents={}},
     L/.style = {decoration={markings, mark=at position 0.4 with {\arrow{>}}},
                 postaction={decorate}},
    EN/.style = {sloped, font=\footnotesize},
every edge/.append style = {L}
                 ]
% main nodes
\node (A) [dot];
\node (B) [dot,below right=of A];%  {2};
\node (C) [dot,below=of B];%        {3};
% dots
\draw[L]    ($(A)+(0, 5mm)$) circle (5mm) node {1};
\draw[L]    ($(B)+( 5mm,0)$) circle (5mm) node {2};
\draw[L]    ($(C)+( 5mm,0)$) circle (5mm) node {3};
% draw the connecting line
\draw   (A) edge node[EN,above] {some text above}
                 node[EN,below] {some text below} (B)
        (B) edge node[EN,below] {text}      (C)
        ;
    \end{tikzpicture}
\end{document}