tikzpicture 弯曲箭头

Question

我正在尝试制作一个 I 形图，其中包含两个框，一个在另一个上方，以及两个箭头：我希望箭头是弯曲的（那将是一种圆形流程图）并且只朝一个方向。虽然我自己搜索到的最好结果是一条直线双向垂直箭头。有人能帮我吗？

编辑

我还想了解其他类型的箭。我正在寻找一种更厚实的箭，但还没找到。有人能给我指点一下吗？

附加问题

如何使箭头旁边的文字水平放置？

我使用的代码是：

\begin{document} 
\usepackage{color, colortbl} 
\usepackage{tikz}  
\usetikzlibrary{arrows,positioning,shapes,backgrounds,fit}  
\begin{figure}[ht]
 \centering
        \scalebox{.8}{
        \begin{tikzpicture}[
        node distance= 9em and 4em,
        sloped]
        \tikzset{
        box/.style = {
            fill=blue!15,
            shape=rectangle, 
            rounded corners,
                draw=blue!40, 
                align=center,
                %minimum size={10pt},
                text = black,
                font=\fontsize{12}{12}\selectfont},
        dummybox/.style = {
            shape=circle,  
                align=center, 
                minimum size={width("rrrrrrrrrrr")+2pt}},
        arrow/.style={
            color=black,
            draw=blue,
            -latex,
                font=\fontsize{8}{8}\selectfont},
        }

        \node[box](B1){Node $A$};
        \node[box, below = of B1](S1){Node $B$};
        \draw[arrow](B1) to node[above]{Flow: $\alpha$ } (S1);

        \draw[arrow](S1) to node[above]{Flow: $-\beta$ } (B1);
\end{tikzpicture}}
\end{figure} 
\end{document}

Answer 1

编辑： 或者：

\documentclass[tikz, border=3mm]{standalone}
\usetikzlibrary{arrows.meta, positioning}

\begin{document}
    \begin{tikzpicture}
\tikzset{
node distance = 9em and 4em,
sloped,
   box/.style = {%
    shape=rectangle,
    rounded corners,
    draw=blue!40,
    fill=blue!15,
    align=center,
    font=\fontsize{12}{12}\selectfont},
 arrow/.style = {%
    draw=blue!30,
    line width=2mm,% <-- select desired width
    -{Triangle[length=3mm]},
    shorten >=1mm, shorten <=1mm,
    font=\fontsize{8}{8}\selectfont},
    }
\node[box](B1){Node $A$};
\node[box, below = of B1](S1){Node $B$};
\draw[arrow](B1) to [bend left,looseness=1.2] node[above] {Flow: $\alpha$} (S1);
\draw[arrow](S1) to [bend left,looseness=1.2] node[above] {Flow: $-\beta$} (B1);
    \end{tikzpicture}
\end{document}

附录： 由于slanted中的选项，箭头处的文本与其对齐\tikzset{...}。如果删除它，文本将显示为水平对齐：

在这种情况下，如果在库的帮助下将箭头处的文本输入为标签，那么它也会对齐quotes：

\documentclass[tikz, border=3mm]{standalone}
\usetikzlibrary{arrows.meta, positioning, quotes}

\begin{document}
    \begin{tikzpicture}
\tikzset{
node distance = 9em and 4em,
%    sloped, % <-- removed for horizontal align of arrows labels
    box/.style = {%
    shape=rectangle,
    rounded corners,
    draw=blue!40,
    fill=blue!15,
    align=center,
    font=\fontsize{12}{12}\selectfont},
 arrow/.style = {%
    draw=blue!30,
    line width=2mm,% <-- select desired width
    -{Triangle[length=3mm]},
    shorten >=1mm, shorten <=1mm,
    font=\fontsize{8}{8}\selectfont},
    }
\node[box](B1){Node $A$};
\node[box, below = of B1](S1){Node $B$};
\draw[arrow](B1) to [bend left,looseness=1.2,"Flow: $\alpha$"] (S1);
\draw[arrow](S1) to [bend left,looseness=1.2,"Flow: $-\beta$"] (B1);
    \end{tikzpicture}
\end{document}

Answer 2

您可以使用 获得弯曲的箭头to[out=alpha,in=beta]。其中alpha 是曲线离开起始坐标的角度，beta是曲线到达目标坐标的角度。

代码

\documentclass{article}
\usepackage{color, colortbl} 
\usepackage{tikz}  
\usetikzlibrary{arrows,positioning,shapes,backgrounds,fit}  
\begin{document} 
\begin{figure}[ht]
 \centering
        \scalebox{.8}{
        \begin{tikzpicture}[
        node distance= 9em and 4em,
        sloped]
        \tikzset{
        box/.style = {
            fill=blue!15,
            shape=rectangle, 
            rounded corners,
                draw=blue!40, 
                align=center,
                %minimum size={10pt},
                text = black,
                font=\fontsize{12}{12}\selectfont},
        dummybox/.style = {
            shape=circle,  
                align=center, 
                minimum size={width("rrrrrrrrrrr")+2pt}},
        arrow/.style={
            color=black,
            draw=blue,
            -latex,
                font=\fontsize{8}{8}\selectfont},
        }

        \node[box](B1){Node $A$};
        \node[box, below = of B1](S1){Node $B$};
        \draw[arrow](B1.west) to [out=190,in=170] node[above]{Flow: $\alpha$ } (S1.west);

        \draw[arrow](S1.east) to [out=10,in=-10] node[above]{Flow: $-\beta$ } (B1.east);
\end{tikzpicture}}
\end{figure} 
\end{document}

结果