Tikz fit library to include shapes but exclude (cut out) others?

Question

Below is an example using the fit library to put a highlight around nodes A, B, and C. What if I wanted to exclude D? (obviously it would have to be a non-rectangular shape)

I guess I'm looking for a way to have union/intersection/difference of shapes.

\documentclass{standalone}
\usepackage{tikz}
\usetikzlibrary{shadows,arrows,positioning,fit,backgrounds,shapes,patterns}
\begin{document}
\begin{tikzpicture}[node distance=5mm, auto,
    block/.style={
        % The shape:
        rectangle, minimum size=6mm, minimum height=6mm, minimum width=30mm,
        rounded corners=1mm,
        node distance=8mm,
        % The rest
        thick,draw=black,
        top color=white,
        bottom color=myblue!15,
        font=\sffamily\footnotesize,
        drop shadow
    },
    area/.style={
        rectangle,
        fill=green!80!black, opacity=0.2,
        draw=black
    },
    >=latex
    ]
        \node (a) {A};
        \node [right=of a] (b) {B};
        \node [below=of a] (c) {C};
        \node [right =of c] (d) {D};
        \node [area, fit=(a) (b) (c)] {};   
\end{tikzpicture}
\end{document}

This is similar to How to perform not rectangular fit with tikz? but not the same.

See also: padded boundary of convex hull and Highlight a group of nodes in a tikz tree. — Claudio Fiandrino, Mar 26 '21 at 08:27

Zarko · Answer 1 · 2021-03-26T07:12:06.560

3

See, if the following solution is appropriate to you:

\documentclass[border=3mm]{standalone}
\usepackage{tikz}
\usetikzlibrary{arrows,backgrounds,fit,patterns,positioning,shadows,shapes}
\begin{document}
    \begin{tikzpicture}[
    node distance=5mm, 
    auto,
every node/.style={inner sep=2mm, minimum size=7mm}
                        ]
\node (a)               {A};
\node (b) [right=of a]  {B};
\node (c) [below=of a]  {C};
\node (d) [right=of c]  {D};
%
\draw[draw=gray, rounded corners, thick, fill=green!80!black, opacity=0.2]
    (a.north) -| (b.south east) -- (c.south east) -| 
    (a.west) |- (a.north);
\end{tikzpicture}
\end{document}

edited Mar 26 '21 at 07:12

answered Mar 10 '16 at 19:19

Zarko

296,517

that works in this sample case, but it defeats the point of using the "fit" library. My real problem involves a much more complicated set of shapes. – Jason S Mar 10 '16 at 19:21
I'm afraid, that there not exist a shape, which be appropriate for your needs. So, one solution can be just draw line around selected nodes. In more complex situation, the curve will become more complicated ... some case you can use ellipse, however its positioning is not so simple. In a many cases it can't avoid some nodes. – Zarko Mar 10 '16 at 19:29
1

+1 Esp. |- and -| is useful, would like to know more about this. – Ilonpilaaja Mar 26 '21 at 05:39
2

@Ilonpilaaja, see TikZ & PGF manual, subsection 13.3.1 Intersections of Perpendicular Lines, page 144 (version 3.1.8b). – Zarko Mar 26 '21 at 07:17

Tikz fit library to include shapes but exclude (cut out) others?

1 Answers1