当一章只有一个图时，省略图编号中的 .1

Question

在书籍类中，图片默认编号为 \thechapter.\arabic{figure}。但是，当一章中只有一个图片时，{figure} 编号是多余的。

在这种情况下，我该如何从图形标签中删除 \arabic{figure}，以便单个图形仅被标记和引用为 Figure \thechapter 而不是 Figure \thechapter.\arabic{figure}

在我的 MWE 中，第 1 章包含两个图（带有默认标签），第 2 章仅包含一个图。如何让该图仅标记为图 2，而不是图 2.1

\documentclass{book}
\usepackage{graphicx}

\begin{document}

\chapter{First chapter with two figures}

In this chapter, Figures \ref{fig1.1} and \ref{fig1.2} are labeled as intended.

\begin{figure}[tbh]
    \centering
    \includegraphics[height=3cm]{example-image-a}
    \caption{Figure is labeled 1.1 as intended}
    \label{fig1.1}
\end{figure}

\begin{figure}[tbh]
    \centering
    \includegraphics[height=3cm]{example-image-b}
    \caption{Figure is labeled 1.2 as intended}
    \label{fig1.2}
\end{figure}

\chapter{Second chapter with one single figure}

In this chapter the only Figure \ref{fig2} should be labeled and referenced as just 2, not 2.1.

\begin{figure}[tbh]
    \centering
    \includegraphics[height=3cm]{example-image-c}
    \caption{This is the only figure in this chapter. The .1 in the numbering is redundant and I would like to remove it.}
    \label{fig2}
\end{figure}

\end{document}

我之所以要从孤立数字中删除 \arabic{figure} 是因为 .1 可以被解释为至少 .2 的含义。

请注意，我建议的编号使所有图形标签保持唯一。

Answer 1

如果您认为有更多章节只包含一个图片的标签，我建议关闭每个章节重置图片编号的功能。这样标签将在整个文档中保持唯一。

实现上述目标的一种方法是使用

\counterwithout*{figure}{chapter}

带星号的版本，以便\thefigure整个文档的格式保持不变。然后，在不需要章节编号的图形环境中重新定义标签。slfigure为此，我创建了一个名为的新环境，其中包含以下行

\renewcommand*{\thefigure}{\arabic{figure}}

以下是示例

\documentclass[openany]{book}   % [openany] only for demonstration to avoid empty pages
\usepackage{graphicx}
\usepackage[Export]{adjustbox}  % For \adjustboxset

\counterwithout*{figure}{chapter}    % Prevents from resetting figure numbers 
\adjustboxset{width=0.5\linewidth}   % To avoid repetition with \inlcudegraphics[width=0.5\linewidth]{...}

% This environment redefines figure labelling, locally
\NewDocumentEnvironment{slfigure}{O{} +b}{
  \begin{figure}[#1]
    \renewcommand*{\thefigure}{\arabic{figure}}
    #2
  \end{figure}
}{}


\begin{document}
\chapter{Chapter with only one figure}
In this chapter the only Figure \ref{fig1} should be referenced as just 1, not 1.1.

\begin{slfigure}[tbh]
  \centering
  \includegraphics{example-image-a}
  \caption{Single figure}
  \label{fig1}
\end{slfigure}


\chapter{Chapter with several figures}
In this chapter, the Figures \ref{fig2.2} and \ref{fig2.3} can be referenced as intended.

\begin{figure}[tbh]
  \centering
  \includegraphics{example-image-b}
  \caption{Figure is labeled 2.2 as intended}
  \label{fig2.2}
\end{figure}

A sentence between figures

\begin{figure}[tbh]
  \centering
  \includegraphics{example-image-c}
  \caption{Figure is labeled 2.3 as intended}
  \label{fig2.3}
\end{figure}


\chapter{Chapter with only one figure}
The second chapter with a single Figure~\ref{fig:4}

\begin{slfigure}[tbh]
  \centering
  \includegraphics{example-image}
  \caption{Single figure no. 4}
  \label{fig:4}
\end{slfigure}
\end{document}

Answer 2

• 欢迎来到 TeX.SE！
• 您的问题不完全清楚：应该如何对之前插入的数字进行编号\section{...}？
• 我预计，这就像没有章节一样
• 在这种情况下，请尝试在序言中添加以下代码片段：

\usepackage{etoolbox}
\AtBeginEnvironment{figure}%
{
\ifnum\arabic{section}=0
    \renewcommand\thefigure{\thechapter.\arabic{figure}}
\else
    \renewcommand\thefigure{\thesection.\arabic{figure}}
\fi
}

• 完成 MWE（稍微改变了你的 MWE）

\documentclass{book}
\usepackage{graphicx}

\usepackage{etoolbox}
\AtBeginEnvironment{figure}%
{
\ifnum\arabic{section}=0
    \renewcommand\thefigure{\arabic{figure}}
\else
    \renewcommand\thefigure{\thesection.\arabic{figure}}
\fi
}

\begin{document}

\chapter{Chapter with only one figure}

In this chapter the only Figure \ref{fig1} should be referenced as just 1, not 1.1.



\begin{figure}[ht]
    \centering
    \includegraphics[height=3cm]{example-image-a}
    \caption{This is the only figure in this chapter. The .1 in the numbering is redundant and I would like to remove it.}
    \label{fig1}
\end{figure}


\begin{figure}[ht]
    \centering
    \includegraphics[height=3cm]{example-image-a}
    \caption{This is the only figure in this chapter}
    \label{fig2}
\end{figure}


\chapter{Chapter with several figures}


\begin{figure}[ht]
    \centering
    \includegraphics[height=3cm]{example-image-a}
    \caption{Figure is labeled 2.1 as intended}
    \label{fig2.1}
\end{figure}

\section{first section in the second chapter}
\begin{figure}[ht]
    \centering
    \includegraphics[height=3cm]{example-image-a}
    \caption{Figure is labeled 2.2 as intended}
    \label{fig2.2}
\end{figure}

\end{document}

给出