忽略 tikz 边界框的内分离

Question

有没有办法在计算图片的边界框时忽略由tikz产生的空白？nodeinner sep

考虑以下 MWE：

\documentclass{article}

\usepackage[showframe,pass]{geometry}
\usepackage{tikz}

\begin{document}

\noindent \begin{tikzpicture}
\node[inner sep=0pt] (X) {X};
\draw (X) -- ++ (0.5, 0);
\draw[gray] (current bounding box.south west) rectangle (current bounding box.north east);
\end{tikzpicture}

\noindent X

\noindent \begin{tikzpicture}
\node[inner sep=2pt] (X) {X};
\draw (X) -- ++ (0.5, 0);
\draw[gray] (current bounding box.south west) rectangle (current bounding box.north east);
\end{tikzpicture}

\end{document}

输出如下：

在此示例中，inner sep在从节点/到节点绘制线条时很有用（参见示例中的水平线），但另一方面，它会X相对于普通文本缩进第二个。某种将边界框指定为包含所有“墨水”的最小矩形（从而剪掉所有inner seps 以及可能不必要地扩展边界框的其他空白）的方法在这里会很棒...

Answer 1

该解决方案实际上并没有忽略inner sep边界框计算，但在许多情况下可能会给出所需的结果。

看起来 的值outer sep不会影响边界框。因此使用outer sep并设置inner sep = 0即可解决问题。

这种方法甚至对其他形状也有效。在这种情况下，负数inner sep（或inner xsep或inner ysep）可能有助于快速而粗略的微调。

\documentclass[border = 1, varwidth]{standalone}
\usepackage{tikz}
\begin{document}
    \begin{tikzpicture}
        \node[inner sep = 0, outer sep = 0.3333em] (X) {X};
        \foreach \a in {0, 5, ..., 90} \draw (X) -- ++(\a:2em);
        \fill[black, opacity = 0.25] (current bounding box.south west)
                           rectangle (current bounding box.north east);
    \end{tikzpicture}
    \begin{tikzpicture}
        \node[inner sep = 0em, outer sep = 0.3333em, circle] (X) {X};
        \foreach \a in {0, 5, ..., 90} \draw (X) -- ++(\a:2em);
        \fill[black, opacity = 0.25] (current bounding box.south west)
                           rectangle (current bounding box.north east);
    \end{tikzpicture}

    \pgfkeysvalueof{/pgf/inner xsep}
\end{document}

我已打印出默认值以inner sep供参考。

Answer 2

我喜欢 krnk 的回答，这正是我想要的。

从 Ti 复制的代码量钾可以使用形状继承机制来减少 Z（我不知道这在原始答案时可能还没有提供）。

我还更改了背景路径，这样无需更新边界框即可创建原始矩形。例如，这样就可以将矩形填充为白色。

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{backgrounds}

\makeatletter
\pgfdeclareshape{tight}{
    % inherit as much stuff as possible from the rectangle shape
    \inheritsavedanchors[from=rectangle]
    \foreach \x in {east,west} \foreach \y in {north,mid,base,south} {
        \inheritanchor[from=rectangle]{\y\space\x}
    }
    \foreach \x in {east,west,north,mid,base,south,center,text} {
        \inheritanchor[from=rectangle]{\x}
    }
    \inheritanchorborder[from=rectangle]
    \inheritbackgroundpath[from=rectangle]

    \savedanchor\tightnortheast{%
        \pgfpoint{\wd\pgfnodeparttextbox}
                 {\ht\pgfnodeparttextbox}%
    }

    \savedanchor\tightsouthwest{%
        \pgfpoint{0pt}
                 {-\dp\pgfnodeparttextbox}%
    }

    \backgroundpath{%
        % move to each of the tight corners, updating the bounding box
        \pgfpathmoveto\tightsouthwest
        \pgfpathmoveto\tightnortheast
        \pgfpathmoveto{\tightsouthwest\pgf@xa=\pgf@x\tightnortheast\pgf@x=\pgf@xa}%
        \pgfpathmoveto{\tightsouthwest\pgf@ya=\pgf@y\tightnortheast\pgf@y=\pgf@ya}%

        % draw the usual recangle border without affecting the bounding box
        \pgf@relevantforpicturesizefalse
        \pgfpathrectanglecorners\southwest
                                \northeast
        % this is executed in a grop, so bounding box tracking automatically
        % gets re-enabled if it was enabled to begin with
    }
}
\makeatother

\begin{document}
    \foreach \shape in {rectangle, tight} {
        \par shape = \shape:\par
        \begin{tikzpicture}[framed,tight background]
            \node[\shape] at (0,0) (x) {x};
            \node[\shape] at (1,0) (y) {y};

            \draw (x) -- (y);
        \end{tikzpicture}
    }
\end{document}