使用 tikzpicture 在图形环境中居中标题

Question

我尝试将 tikzpicture 和标题置于图形环境中的中心，但编译时出现问题。似乎标题和 tikzpicture 相对于不同的参考点居中。我使用的是 Overleaf。

\begin{figure}[H]
\centering
\begin{tikzpicture}[scale=1.0]
\begin{axis}[ ymin=0, xlabel = variáveis aleatórias, ylabel = frequência]

\addplot [
    domain=0:10, 
    samples=100, 
    color=red]
    {exp(-x)};
\end{axis}
\end{tikzpicture}
\caption{Some figure}
\end{figure}

Answer 1

正如 Sigur 指出的那样，标题相对于整个 tikzpicture 是居中的，不仅仅是情节，而且是带有标签的情节。如果你真的不想要这个，你可能会弄乱边界框。

\documentclass{article}
\usepackage{float}
\usepackage{pgfplots}
\pgfplotsset{compat=1.16}
\usepackage{lipsum}
\begin{document}
\lipsum[1]
\begin{figure}[H]
\centering
\begin{tikzpicture}[scale=1.0]
\begin{pgfinterruptboundingbox}
\begin{axis}[ ymin=0, xlabel = variáveis aleatórias, ylabel = frequência]

\addplot [
    domain=0:10, 
    samples=100, 
    color=red]
    {exp(-x)};
\end{axis}
\end{pgfinterruptboundingbox}
\path[use as bounding box] ([yshift=-8mm]current axis.south west) rectangle (current axis.north east);
\end{tikzpicture}
\caption{Some figure}
\end{figure}
\lipsum[2]
\end{document}

其他选项包括将标题向左移动，或者更优雅的方式是将相同的空间添加到右侧的边界框。

\documentclass{article}
\usepackage{float}
\usepackage{pgfplots}
\pgfplotsset{compat=1.16}
\usetikzlibrary{calc}
\usepackage{lipsum}
\begin{document}
\lipsum[1]
\begin{figure}[H]
\centering
\begin{tikzpicture}[scale=1.0]
\begin{axis}[ymin=0,
             xlabel=variáveis aleatórias,
             ylabel=frequência,
             ylabel style={alias=ylab}]

\addplot [
    domain=0:10, 
    samples=100, 
    color=red]
    {exp(-x)};
\end{axis}
\path let \p1=($(current axis.west)-(ylab.north)$) 
  in (current axis.east) -- ++(\x1,0);
\end{tikzpicture}
\caption{Some figure}
\end{figure}
\lipsum[2]
\end{document}

这节省了您手动添加的时间yshift。

Answer 2

这是 Marmot 解决方案的变体，使用了 calc tikzlibrary 和[name=...]轴选项。

\documentclass{article}
\usepackage{float}
\usepackage{pgfplots}
\usetikzlibrary{calc}
\pgfplotsset{compat=1.16}
\usepackage{lipsum}
\begin{document}
\lipsum[1]
\begin{figure}[H]
\centering
\begin{tikzpicture}[scale=1.0]
\begin{axis}[ymin=0, xlabel = variáveis aleatórias, ylabel = frequência,
    name=border]
\addplot [
    domain=0:10, 
    samples=100, 
    color=red]
    {exp(-x)};
\end{axis}
% center tikzpicture relative to axis (border)
\path ($(border.center)!-1!(current bounding box.west)$);
\draw[blue] (current bounding box.south west) rectangle (current bounding box.north east);% demo only
\end{tikzpicture}
\caption{Some figure}
\end{figure}
\lipsum[2]
\end{document}

---

此解决方案将标题放在 tikzpicture 内，在轴边框内（水平）。这使 tikzpicture 更小，但为标题提供的空间却少得多。

\documentclass{article}
\usepackage{float}
\usepackage{pgfplots}
\pgfplotsset{compat=1.16}
\usepackage{lipsum}

\newlength{\tempwidth}

\begin{document}
\lipsum[1]
\begin{figure}[H]
\centering
\begin{tikzpicture}[scale=1.0]
\begin{axis}[ymin=0, xlabel = variáveis aleatórias, ylabel = frequência,
    name=border]
\addplot [
    domain=0:10, 
    samples=100, 
    color=red]
    {exp(-x)};
\end{axis}
% center tikzpicture relative to axis (border)
\pgfextractx{\tempwidth}{\pgfpointdiff{\pgfpointanchor{border}{west}}{\pgfpointanchor{border}{east}}}%
\node[below] at (border.south |- current bounding box.south) {\begin{minipage}{\tempwidth}
    \caption{Some figure}
\end{minipage}};
\draw[blue] (current bounding box.south west) rectangle (current bounding box.north east);% demo only
\end{tikzpicture}

\end{figure}
\lipsum[2]
\end{document}