如何在 pdfplot 中将刻度标签拆分成多行？

Question

如何要求 pgfplot 将太长的标签分成多行？

例如，我有一张图表，描述了一份问卷的答案。问题应该是 Y 轴的标签，用ticklabelsPDFPlots 的术语来说。然而，许多问题都很长，这些标签的空间应该限制在 5 厘米以内。

这是我目前的尝试。

\documentclass{article}
\usepackage{tikz}
\usepackage{pgfplots, pgfplotstable}
\pgfplotsset{compat=1.17}

\begin{document}

\pgfplotstableread[col sep=&]{
Q & A & B & C
Q1 Very long question text that should be split in multiple lines & 0 & 1 & 3
Q2 Shorter question & 0 & 2 & 2
Q3 Another question with a long text & 2 & 1 & 1
}{\answers}

\begin{tikzpicture}
\begin{axis}[
    xbar stacked,
    y=0.8cm,
    y dir=reverse,
    xmin=0, xmax=4,
    ytick=data,
    yticklabels from table={\answers}{Q},
    yticklabel style={font=\footnotesize, width=5cm}, % << ERROR: width is not a recognized tikz key
]

\addplot [fill=red] table [x=A, y expr=\coordindex] {\answers};
\addplot [fill=yellow] table [x=B, y expr=\coordindex] {\answers};
\addplot [fill=green] table [x=C, y expr=\coordindex] {\answers};

\end{axis}
\end{tikzpicture}

\end{document}

该文档无法编译并出现以下错误：Package pgfkeys Error: I do not know the key '/tikz/width', to which you passed '5cm', and I am going to ignore it.

有没有办法强制每个刻度标签都有设定的宽度？

Answer 1

pgfplots刻度标签是tikz节点，这里需要选项text width=<dimension>。

\documentclass{article}
\usepackage{tikz}
\usepackage{pgfplots, pgfplotstable}
\pgfplotsset{compat=1.17}

\begin{document}

\pgfplotstableread[col sep=&]{
Q & A & B & C
Q1 Very long question text that should be split in multiple lines & 0 & 1 & 3
Q2 Shorter question & 0 & 2 & 2
Q3 Another question with a long text & 2 & 1 & 1
}{\answers}

\begin{tikzpicture}
\begin{axis}[
    xbar stacked,
    y=0.8cm,
    y dir=reverse,
    xmin=0, xmax=4,
    ytick=data,
    yticklabels from table={\answers}{Q},
    yticklabel style={font=\footnotesize, text width=5cm}
]

\addplot [fill=red] table [x=A, y expr=\coordindex] {\answers};
\addplot [fill=yellow] table [x=B, y expr=\coordindex] {\answers};
\addplot [fill=green] table [x=C, y expr=\coordindex] {\answers};

\end{axis}
\end{tikzpicture}

\end{document}

使用选项text width或align=left|center|right，您还可以通过插入来手动指定换行符\\。

Answer 2

我创建一个新列，将 Q 列的内容嵌入其中parbox。

\documentclass{article}
\usepackage{tikz}
\usepackage{pgfplots, pgfplotstable}
\pgfplotsset{compat=1.17}



\begin{document}
    
    \pgfplotstableread[col sep=&]{
        Q & A & B & C
        Q1 Very long question text that should be split in multiple lines & 0 & 1 & 3
        Q2 Shorter question & 0 & 2 & 2
        Q3 Another question with a long text & 2 & 1 & 1
    }{\answers}

    \pgfplotstablecreatecol[create col/assign/.code={%
        \getthisrow{Q}\entry%
        \edef\entry{\noexpand\parbox{5cm}{\entry}}%
        \pgfkeyslet{/pgfplots/table/create col/next content}\entry%
    }]{Qwidth}{\answers}
        
    \begin{tikzpicture}
    \begin{axis}[
    xbar stacked,
    y=0.8cm,
    y dir=reverse,
    xmin=0, xmax=4,
    ytick=data,
    yticklabels from table={\answers}{Qwidth},
    yticklabel style={font=\footnotesize},
    ]
    
    \addplot [fill=red] table [x=A, y expr=\coordindex] {\answers};
    \addlegendentry{A}
    \addplot [fill=yellow] table [x=B, y expr=\coordindex] {\answers};
    \addlegendentry{B}
    \addplot [fill=green] table [x=C, y expr=\coordindex] {\answers};
    \addlegendentry{C}
    
    \end{axis}
    \end{tikzpicture}
    
\end{document}