tikz 流程图中来自和到同一节点的路径

Question

我正在使用 tikz 直接在 LaTeX 文档中创建流程图。虽然我使用 LaTeX 有相当多的经验，但我承认自己是 tikz 的新手。

我的问题是当尝试用流程图显示无限循环时，即在同一节点开始和结束的边或路径。

例如，

是使用以下 LaTeX 代码我想要的结果（右）和我得到的结果（左）的示例：

\usetikzlibrary{shapes.geometric,arrows}

\tikzstyle{decision} = [ diamond, draw, fill=blue!20, text width=4.5em, text badly centered, node distance=3cm, inner sep-0pt]  
\tikzstyle{block} = [ rectangle, draw, fill=blue!20, text width=5em, text badly centered, rounded corners, minimum height=4em]  
\tikzstyle{line} = [ draw, -latex']  
\tikzstyle{terminator} = [ draw, ellipse, fill=red!20, node distance=3cm, minimum height=2em]  

\begin{tikzpicture}[node distance=2cm, auto]  
  \node [terminator]           (puc)  {Power-Up Reset};  
  \node [block, below of=puc]  (wdt)  {Stop Watchdog};  
  \node [block, below of=wdt]  (port) {Setup Port Pins};  
  \node [block, below of=port] (loop) {Loop Forever};  
  \path [line] (puc)  -- (wdt);  
  \path [line] (wdt)  -- (port);  
  \path [line] (port) -- (loop);  
  \path [line] (loop) -- (loop);  
\end{tikzpicture}

我想我需要一些更复杂的东西。

Answer 1

只需更改\path [line] (loop) -- (loop);为\path [line] (loop) edge[loop right] ();(或loop below或loop left)。

或者，将其更改为\path [line] (loop) |- ($(loop.south east) + (0.5,-0.5)$) |- (loop);（使用\usetikzlibrary{calc}）

此外，加上rounded corners（例如\path [line,rounded corners] (loop) |- ($(loop.south east) + (0.5,-0.5)$) |- (loop);）可得

Answer 2

最小示例中的更多细节可能会非常有用，因为有一些 tikZ 库对于编译示例是必要的。

您可以通过向最后一条路径添加一个坐标来获得所需的循环，强制路径通过该点绘制。

\documentclass{minimal}
\usepackage{tikz}
\usetikzlibrary{arrows,shapes}

\tikzstyle{decision}=[diamond,draw,fill=blue!20,text width=4.5em,text badly centered,node distance=3cm,inner sep=0pt]  
\tikzstyle{block}=[rectangle,draw,fill=blue!20,text width=5em,text badly centered,rounded corners,minimum height=4em]  
\tikzstyle{line}=[draw,-latex']  
\tikzstyle{terminator}=[draw,ellipse,fill=red!20,node distance=3cm,minimum height=2em]  

\begin{document}
  \begin{tikzpicture}[node distance=2cm,auto]  
    \node[terminator]           (puc)  {Power-Up Reset};  
    \node[block, below of=puc]  (wdt)  {Stop Watchdog};  
    \node[block, below of=wdt]  (port) {Setup Port Pins};  
    \node[block, below of=port] (loop) {Loop Forever};  
    \path[line] (puc)  -- (wdt);  
    \path[line] (wdt)  -- (port);  
    \path[line] (port) -- (loop);  
    \path[line] (loop) |- +(2,-1) |- (loop.east);  
  \end{tikzpicture}
\end{document}