如何插入“T”形的子图？

Question

有人能帮我插入“T”形的子图吗？还有如何控制两个子图之间的间距，例如“子图 1”和“子图 2”之间的水平间距以及“子图 3”和“子图 4”之间的垂直间距（我指的是附图中的子图）。是否可以根据子图的高度插入一条细线，以分隔彼此相邻的两个子图？

Answer 1

像这样吗？

\documentclass{article}
\usepackage{graphicx}
\usepackage{subcaption}
\begin{document}
\begin{figure}
  \centering
  \begin{subfigure}{.4\linewidth}
    \centering
    \includegraphics[width=.8\linewidth]{example-image-duck}
    \caption{Some duck}
    \label{fig:duck1}
  \end{subfigure}
  \begin{subfigure}{.4\linewidth}
    \centering
    \includegraphics[width=.8\linewidth]{example-image-duck}
    \caption{Some other duck}
    \label{fig:duck2}
  \end{subfigure}
  \begin{subfigure}{\linewidth}
    \centering
    \includegraphics[width=.32\linewidth]{example-image-duck}
    \caption{Another duck}
    \label{fig:duck3}
  \end{subfigure}
  \begin{subfigure}{\linewidth}
    \centering
    \includegraphics[width=.32\linewidth]{example-image-duck}
    \caption{Another duck the second time}
    \label{fig:duck4}
  \end{subfigure}
  \caption{Many ducks!}
  \label{fig:manyducks}
\end{figure}
\end{document}

添加垂直线和一些自定义间距

\documentclass{article}
\usepackage{graphicx}
\usepackage{subcaption}
\begin{document}
\begin{figure}
  \centering
  \begin{tabular}{c|c}
  \begin{subfigure}{.4\linewidth}
    \centering
    \includegraphics[width=.8\linewidth]{example-image-duck}
    \caption{Some duck}
    \label{fig:duck1}
  \end{subfigure} &
  \begin{subfigure}{.4\linewidth}
    \centering
    \includegraphics[width=.8\linewidth]{example-image-duck}
    \caption{Some other duck}
    \label{fig:duck2}
  \end{subfigure}
  \end{tabular}
  \vspace{1cm}\par
  \begin{subfigure}{\linewidth}
    \centering
    \includegraphics[width=.32\linewidth]{example-image-duck}
    \caption{Another duck}
    \label{fig:duck3}
  \end{subfigure}
  \vspace{2cm}\par
  \begin{subfigure}{\linewidth}
    \centering
    \includegraphics[width=.32\linewidth]{example-image-duck}
    \caption{Another duck the second time}
    \label{fig:duck4}
  \end{subfigure}
  \caption{Many ducks!}
  \label{fig:manyducks}
\end{figure}
\end{document}