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如何将文本置于流程图中的一行中央

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如何将文本置于流程图中的一行中央

大家好，我遇到了以图片左侧的 C 形线为中心的问题。正确的做法是什么？

\documentclass[11pt,a4paper,oneside]{article}
\usepackage{fullpage}
\usepackage[italian]{babel}
\usepackage[utf8]{inputenc}
\usepackage{amsfonts}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{amsthm}
\usepackage{tikz}
\usepackage{pgfplots}

\pgfplotsset{compat=1.12}
\usetikzlibrary{positioning}
\usetikzlibrary{decorations.markings}
\usetikzlibrary{shapes.multipart, calc}
\usetikzlibrary{shapes,arrows}

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

\begin{document}
\begin{figure}[hb]
    \centering
    \begin{tikzpicture}[node distance = 2.5cm, auto]
    \node[block, label={360:$O(1)$}] (init) {inizializza};
    \node[decision, below of=init, label={360:$O(1)$}] (cond) {condizione};
    \node[block, below of=cond, label={360:$O(f(n))$}] (corpo) {corpo del ciclo};
    \node[block, below of=corpo,label={360:$O(1)$}] (reinit) {re-inizializza};

    \path[line] (init) -- (cond);
    \path[line] (cond) -- (corpo);
    \path[line] (corpo) -- (reinit);
    \path[line] (reinit.west) -- ++(-0.5,0) -- node[midway]{$g(n)$ volte} ++(0,1) |- (cond.west);

    \end{tikzpicture}
    \caption{Schematizzazione del costrutto \texttt{FOR}.}
    \label{fig:ciclofor}
\end{figure}
\end{document}

答案1

您必须将 分成|-两条线段。以下是其中一种方法：

\documentclass[11pt,a4paper,oneside]{article}
\usepackage{fullpage}
\usepackage[italian]{babel}
\usepackage[utf8]{inputenc}
\usepackage{amsfonts}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{amsthm}
\usepackage{tikz}
\usepackage{pgfplots}

\pgfplotsset{compat=1.12}
\usetikzlibrary{positioning}
\usetikzlibrary{decorations.markings}
\usetikzlibrary{shapes.multipart, calc}
\usetikzlibrary{shapes,arrows}

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

\begin{document}
\begin{figure}[hb]
    \centering
    \begin{tikzpicture}[node distance = 2.5cm, auto]
    \node[block, label={360:$O(1)$}] (init) {inizializza};
    \node[decision, below of=init, label={360:$O(1)$}] (cond) {condizione};
    \node[block, below of=cond, label={360:$O(f(n))$}] (corpo) {corpo del ciclo};
    \node[block, below of=corpo,label={360:$O(1)$}] (reinit) {re-inizializza};

    \path[line] (init) -- (cond);
    \path[line] (cond) -- (corpo);
    \path[line] (corpo) -- (reinit);
    \path[line] (reinit.west) -- ++(-0.5,0) coordinate(A) -- node[midway]{$g(n)$ volte} (A|-cond) -- (cond.west);

    \end{tikzpicture}
    \caption{Schematizzazione del costrutto \texttt{FOR}.}
    \label{fig:ciclofor}
\end{figure}
\end{document}

演示

答案2

实际上，您根本不需要拆分|-。根据 tikz 手册（第 17.8 节），当沿着这样的路径放置节点时，midway位置 ( pos=.5) 指的是弯曲处。也就是说，如果您想将标签放置在第一半（垂直）的中间，您需要pos=.25。同样，pos=.75是路径后半部分的中间。

\documentclass[11pt,a4paper,oneside]{article}
\usepackage{fullpage}
\usepackage[italian]{babel}
\usepackage[utf8]{inputenc}
\usepackage{amsfonts}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{amsthm}
\usepackage{tikz}
\usepackage{pgfplots}

\pgfplotsset{compat=1.12}
\usetikzlibrary{positioning}
\usetikzlibrary{decorations.markings}
\usetikzlibrary{shapes.multipart, calc}
\usetikzlibrary{shapes,arrows}

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

\begin{document}
\begin{figure}[hb]
    \centering
    \begin{tikzpicture}[node distance = 2.5cm, auto]
    \node[block, label={360:$O(1)$}] (init) {inizializza};
    \node[decision, below of=init, label={360:$O(1)$}] (cond) {condizione};
    \node[block, below of=cond, label={360:$O(f(n))$}] (corpo) {corpo del ciclo};
    \node[block, below of=corpo,label={360:$O(1)$}] (reinit) {re-inizializza};

    \path[line] (init) -- (cond);
    \path[line] (cond) -- (corpo);
    \path[line] (corpo) -- (reinit);
    \path[line] (reinit.west) -- ++(-0.5,0) |- node[pos=.25]{$g(n)$ volte} (cond.west);

    \end{tikzpicture}
    \caption{Schematizzazione del costrutto \texttt{FOR}.}
    \label{fig:ciclofor}
\end{figure}
\end{document}

在此处输入图片描述

答案3

我赞同 Emma 的回答 :-)，但是，他的代码在这种特殊情况下的简单流程图可以通过使用包变得chains更加简洁：

\documentclass[11pt,a4paper,oneside]{article}
\usepackage{fullpage}
\usepackage[italian]{babel}
\usepackage[utf8]{inputenc}
\usepackage{tikz}
\usetikzlibrary{arrows, 
                calc, chains, 
                shapes,
                }

\begin{document}
\begin{figure}[hb]
    \centering
\begin{tikzpicture}[
    node distance = 1cm, 
      start chain = A going below,
      base/.style = {draw, 
                     text width=5em, align=flush center,
                     on chain=A, join=by line},
  decision/.style = {base, diamond, fill=red!20,
                     aspect=1.2, inner sep=0pt},
     block/.style = {base, rectangle, rounded corners, 
                     fill=blue!20, minimum height=4em},
      line/.style = {-latex'},
                    ]
\node (init)  [block,    label=0:$O(1)$]    {inizializza};
\node (cond)  [decision, label=0:$O(1)$]    {condizione};
\node (corpo) [block,    label=0:$O(f(n))$] {corpo del ciclo};
\node (reinit)[block,    label=0:$O(1)$]    {re- inizializza};
%
\draw[line] (reinit.west) -- ++(-0.5,0) |- node[pos=0.25,left] {$g(n)$ volte} (cond) ;% borowed/stolen from Emma answer
    \end{tikzpicture}
\caption{Schematizzazione del costrutto \texttt{FOR}.}
    \label{fig:ciclofor}
\end{figure}
\end{document}

在上面的 MWE 中，我还tikzsyle用本地节点集样式替换了已弃用的样式。其中针对通用功能定义了样式base。结果类似： 在此处输入图片描述

答案4

因为你得不到答案，所以这是一个快速而又简单的方法。

\documentclass{article}
\usepackage{amsmath}
\usepackage{tikz}
\usetikzlibrary{positioning}
\usetikzlibrary{decorations.markings}
\usetikzlibrary{shapes.multipart, calc}
\usetikzlibrary{shapes,arrows}

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

\begin{document}
\begin{figure}[hb]
    \centering
    \begin{tikzpicture}[node distance = 2.5cm, auto]
    \node[block, label={360:$O(1)$}]                   (init) {inizializza};
    \node[decision, below of=init, label={360:$O(1)$}] (cond) {condizione};
    \node[block, below of=cond, label={360:$O(f(n))$}] (corpo) {corpo del ciclo};
    \node[block, below of=corpo,label={360:$O(1)$}]    (reinit) {re-inizializza};
    \node[coordinate] (lreinit) [left=15pt of reinit] {};
    \node[coordinate] (lcond)   [left=15pt of cond] {};

    \path[line] (init) -- (cond);
    \path[line] (cond) -- (corpo);
    \path[line] (corpo) -- (reinit);
%    \path[line] (reinit.west) -- ++(-0.5,0) -- node[midway]{$g(n)$ volte} ++(0,1) |- (cond.west);
    \draw[->,red] (reinit) -- (lreinit) -- node[midway, left]{$g(n)$ volte} (lcond) -- (cond) ;
    \end{tikzpicture}
    \caption{Schematizzazione del costrutto \texttt{FOR}.}
    \label{fig:ciclofor}
\end{figure}
\end{document}

给予：

在此处输入图片描述

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