如何测量 tikz 图片的高度？

Question

我的文档中有几张由 制作的图形TikZ。它们的大小各不相同。如何获取每张图形的高度以进行一些复杂的计算？

编辑

我想在文本中访问图片的高度（而不是在图片中！），例如“上面的图片高度为\the\tikzheight”。

平均能量损失

\documentclass{article}

\usepackage{tikz}

\begin{document}

    % WHAT HEIGHT DO I HAVE?
    \begin{tikzpicture}[scale=1.5]
        % help lines
        \draw[step=1,help lines,black!20] (-0.95,-0.95) grid (4.95,4.95);
        % axis
        \draw[thick,->] (-1,0) -- (5,0);
        \draw[thick,->] (0,-1) -- (0,5);

        % points
        \foreach \Point/\PointLabel in {(1,1)/A, (3,1)/B, (1,4)/P_1, (3,4)/P_1}
        \draw[fill=black] \Point circle (0.05) node[above right] {$\PointLabel$};
    \end{tikzpicture}

\end{document}

Answer 1

有帮助吗？它绘制图片并将其大小写在其中心。打印值不考虑该scale因素。在这种情况下，实际高度将是 1.5*171.27066pt。

\documentclass{article}

\usepackage{tikz}
\usetikzlibrary{calc}

\begin{document}

    % WHAT HEIGHT DO I HAVE?
\begin{tikzpicture}[scale=1.5]
        % help lines
        \draw[step=1,help lines,black!20] (-0.95,-0.95) grid (4.95,4.95);
        % axis
        \draw[thick,->] (-1,0) -- (5,0);
        \draw[thick,->] (0,-1) -- (0,5);
        % points
        \foreach \Point/\PointLabel in {(1,1)/A, (3,1)/B, (1,4)/P_1, (3,4)/P_1}
        \draw[fill=black] \Point circle (0.05) node[above right] {$\PointLabel$};
        \draw let \p1 = ($(current bounding box.north east)-(current bounding box.south west)$) 
          in node[red] at (current bounding box.center) {(\x1,\p1)}; 
\end{tikzpicture}

\end{document}

更新：

Leo Liu 的答案适合这个特定问题。它使用calc包而不是calctikzlibrary。

\documentclass{article}

\usepackage{tikz}
\usepackage{calc}

\newsavebox\mytikz
\newlength\tikzheight

\begin{document}

\savebox{\mytikz}{%
    % WHAT HEIGHT DO I HAVE?
\begin{tikzpicture}[scale=1.5, transform shape]
        % help lines
        \draw[step=1,help lines,black!20] (-0.95,-0.95) grid (4.95,4.95);
        % axis
        \draw[thick,->] (-1,0) -- (5,0);
        \draw[thick,->] (0,-1) -- (0,5);
        % points
        \foreach \Point/\PointLabel in {(1,1)/A, (3,1)/B, (1,4)/P_1, (3,4)/P_1}
        \draw[fill=black] \Point circle (0.05) node[above right] {$\PointLabel$};
\end{tikzpicture}%
}

\usebox{\mytikz}
\settototalheight\tikzheight{\usebox{\mytikz}}

The picture above has a height of \the\tikzheight.

\end{document}