1

I want to draw or fill a triangle between three nodes in a matrix. The following does not work, so it seems my basic understanding of how matrix nodes work is wrong:

\begin{tikzpicture}
    \matrix[matrix of math nodes, name=m] {
        A & B \\
        C & D \\};
        \draw (m-2-1) -- (m-1-1) -- (m-2-2) -- cycle;
        \fill (m-1-1) -- (m-1-2) -- (m-2-2) --cycle;
\end{tikzpicture}

Instead of a triangle, only one line (the first) is drawn and the shape is not filled at all.

I have so far failed to find an answer online, although this seems pretty basic. That's why I think I am missing something important... Why is the triangle not drawn completely / the shape not filled?

  • You might also try (m-2-1.center) -- (m-1-1.center) ... – John Kormylo Aug 17 '17 at 13:44
  • (m-2-1)--(m-1-1) draws a line from m-2-1.center to m-1-1.center but stopping at node borders. Then your path is made with unconnected fragments which form a non closed path that cannot be filled. – Ignasi Aug 17 '17 at 14:24
1

I think it's because the node are contiguous (if you add nodes={draw} to your code you can see it).

And I think the fill doesn't work because the line is not closed. If you add some space between the nodes and use the coordinates to draw the lines, it works:

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{matrix}
\begin{document}
\begin{tikzpicture}
    \matrix[matrix of math nodes, %nodes={draw},
    row sep=10pt,
    column sep=10pt] (m) {%
        A & B \\
        C & D \\};
\draw[fill] (m-2-1.north east) -- (m-1-1.south east) -- (m-2-2.north west) -- cycle;
\end{tikzpicture}
\end{document}

enter image description here

(Even if I don't know if this is exactly what you're looking for).

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.