在 TikZ 中建立循環箭頭

Question

我正在嘗試創建一個從單字底部伸出的箭頭，然後循環到同一個單字的頂部。重點是為了說明「Operations」的輸出也成為「Operations」的輸入。

我最初的嘗試只是簡單地使用edge[out = -90, in = 90]，但這並不會使箭頭圍繞該單字循環。

\documentclass{article}
\usepackage{tikz}

\begin{document}
\begin{tikzpicture}
    \node at (0,0) (Operations) {Operations};
    \draw [->] (Operations) edge[out = -90, in = 90] (Operations);
\end{tikzpicture}

\end{document}

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編輯

在我的真實範例中，我有一個從上面的節點向下指向「操作」的箭頭，還有一個從「操作」向下指向下面的節點的箭頭。理想情況下，循環箭頭的起點和終點應與這兩個現有箭頭對齊。

\documentclass{article}
\usepackage{tikz}

\begin{document}
\begin{tikzpicture}
    \node at (0,3) (Input) {Input};
    \node at (0,1.5) (Operations) {Operations};
    \node at (0,0) (Output) {Output};
    \draw [->] (Input) -- (Operations);
    \draw [->] (Operations.center) arc (-180:180:1);
    \draw [->] (Operations) -- (Output);
\end{tikzpicture}

\end{document}

Answer 1

這是一個非常好的解決方案，透過新增第三個節點\node at (1,0) (here) {};並將箭頭的大小修改為looseness。

\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
    \node at (0,0) (Operations) {Operations};
    \node at (1,0) (here) {};
    \draw [->] (Operations) to[out=-80, in=-90,looseness=2] (here)    to[out=90,in=80,looseness=2] (Operations);
\end{tikzpicture}

\end{document}

Answer 2

正如我在評論中所說，有精確的數字

\documentclass{article}
\usepackage{tikz}

\begin{document}
\begin{tikzpicture}
    \node at (0,0) (Operations) {Operations};
    \draw [->] (Operations.south)arc(-160:160:1);
\end{tikzpicture}

\end{document}

---

---

另一種方法

\draw[->,shorten <=5pt,shorten >=5pt](Operations.center)arc(-180:180:1);

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第三種方法

\documentclass{article}
\usepackage{tikz}

\begin{document}
\begin{tikzpicture}
    \node at (0,3) (Input) {Input};
    \node at (0,1.5) (Operations) {Operations};
    \node at (0,0) (Output) {Output};
    \draw [->] (Input) -- (Operations);
    \draw [->] (Operations) -- (Output);
    \draw[->](Operations.south)arc(-180:0:1)coordinate(X)
             (Operations.north)+(2,0)--(X)
             (Operations.north)+(2,0)arc(0:180:1);
\end{tikzpicture}

\end{document}