由于标题的长度不同，我无法水平对齐子图

Question

\documentclass{article}

\begin{figure}[!] 
        \centering
        \begin{subfigure}[b]{0.24\textwidth}
                \centering
                \includegraphics[width=\textwidth]{1.eps}
                \caption{1}
                \label{fig:1 is 0}
        \end{subfigure}%
        \hfill 
        \begin{subfigure}[b]{0.24\textwidth}
                \centering
                \includegraphics[width=\textwidth]{2}
                \caption{2}
                \label{fig:2 is the life like}
        \end{subfigure}
        \hfill
        \begin{subfigure}[b]{0.24\textwidth}
                \centering
                \includegraphics[width=\textwidth]{3}
                \caption{3}
                \label{fig:3 is what people and the world like}
        \end{subfigure}
        \hfill
        \begin{subfigure}[b]{0.24\textwidth}
                \centering
                \includegraphics[width=\textwidth]{4}
                \caption{4}
                \label{fig:4 is what the earth and the mars like}
        \end{subfigure}

\end{figure}


\end{document}

Answer 1

在这种情况下，使用\subcaptionbox命令，而不是subfigure；\subcaptionbox自动根据子图的第一个标题行对齐子图。

subfigure以下是使用环境和命令时获得的不同垂直对齐方式的比较\subcaptionbox：

\documentclass{article}
\usepackage[demo]{graphicx}
\usepackage{subcaption}

\begin{document}

\begin{figure}
        \centering
        \begin{subfigure}[b]{0.24\textwidth}
                \centering
                \includegraphics[width=\textwidth]{1.eps}
                \caption{short}
                \label{fig:1}
        \end{subfigure}%
        \hfill 
        \begin{subfigure}[b]{0.24\textwidth}
                \centering
                \includegraphics[width=\textwidth]{2}
                \caption{short text}
                \label{fig:2}
        \end{subfigure}%
        \hfill
        \begin{subfigure}[b]{0.24\textwidth}
                \centering
                \includegraphics[width=\textwidth]{3}
                \caption{a little longer text}
                \label{fig:3}
        \end{subfigure}%
        \hfill
        \begin{subfigure}[b]{0.24\textwidth}
                \centering
                \includegraphics[width=\textwidth]{4}
                \caption{a much longer text goes here}
                \label{fig:4}
        \end{subfigure}
\caption{a general caption}
\label{fig:testa}
\end{figure}

\begin{figure}
\centering
\subcaptionbox{short\label{fig:11}}{\includegraphics[width=.24\linewidth]{1.eps}}\hfill 
\subcaptionbox{short text\label{fig:22}}{\includegraphics[width=.24\linewidth]{2.eps}}\hfill
\subcaptionbox{a little longer text\label{fig:33}}{\includegraphics[width=.24\linewidth]{3.eps}}\hfill
\subcaptionbox{a much longer text goes here\label{fig:44}}{\includegraphics[width=.24\linewidth]{4.eps}}
\caption{a general caption}
\label{fig:testb}
\end{figure}

\end{document}

选项demo只是graphicx用黑色矩形替换实际图形；不是在实际文档中使用该选项。