I have a tikz-feynman diagram that has a wide aspect ratio, and I'd like to change the aspect ratio to be more square.
cascade.txt:
\documentclass[tikz]{standalone}
\def\axisdefaultwidth{12cm}
\def\axisdefaultheight{9cm}
\usepackage{tikz-feynman}
\begin{document}
\feynmandiagram [small, layered layout, vertical=a to b] {
alpha -- [photon, edge label=\(\gamma_o\)] a0,
a0 -- [anti fermion, edge label=\(e^{+}\)] a1 ,
a0 -- [fermion, edge label=\(e^{-}\)] a2 ,
a1 -- [photon, edge label=\(\gamma\)] a3 ,
a1 -- [anti fermion, edge label=\(e^{+}\)] a4 ,
a2 -- [photon, edge label=\(\gamma\)] a5 ,
a2 -- [fermion, edge label=\(e^{-}\)] a6 ,
a3 -- [anti fermion, edge label=\(e^{+}\)] a7 ,
a3 -- [fermion, edge label=\(e^{-}\)] a8 ,
a4 -- [photon, edge label=\(\gamma\)] a9 ,
a4 -- [anti fermion, edge label=\(e^{+}\)] a10 ,
a5 -- [anti fermion, edge label=\(e^{+}\)] a11 ,
a5 -- [fermion, edge label=\(e^{-}\)] a12 ,
a6 -- [photon, edge label=\(\gamma\)] a13 ,
a6 -- [fermion, edge label=\(e^{-}\)] a14 ,
a7 -- [photon, edge label=\(\gamma\)] a15 ,
a7 -- [anti fermion, edge label=\(e^{+}\)] a16 ,
a8 -- [photon, edge label=\(\gamma\)] a17 ,
a8 -- [fermion, edge label=\(e^{-}\)] a18 ,
a9 -- [anti fermion, edge label=\(e^{+}\)] a19 ,
a9 -- [fermion, edge label=\(e^{-}\)] a20 ,
a10 -- [photon, edge label=\(\gamma\)] a21 ,
a10 -- [anti fermion, edge label=\(e^{+}\)] a22 ,
a11 -- [photon, edge label=\(\gamma\)] a23 ,
a11 -- [anti fermion, edge label=\(e^{+}\)] a24 ,
a12 -- [photon, edge label=\(\gamma\)] a25 ,
a12 -- [fermion, edge label=\(e^{-}\)] a26 ,
a13 -- [anti fermion, edge label=\(e^{+}\)] a27 ,
a13 -- [fermion, edge label=\(e^{-}\)] a28 ,
a14 -- [photon, edge label=\(\gamma\)] a29 ,
a14 -- [fermion, edge label=\(e^{-}\)] a30 ,
};
\end{document}
Which is compiled via:
$ lualatex cascade.tex
Which renders to this: cascade.pdf which has to be shrunk too much to fit on an A4 page. I can force the width and height when I include it in my main document, but that also skews the text labels, making it look pretty bad.
How can I make the aspect ratio more square without distorting the text labels?

\documentclass[tikz]{standalone}your snippet does not compile on my machine, but with\documentclass[tikz]{article}it does. – Jan 19 '18 at 21:24\RequirePackage{luatex85}as the very first instruction, with a recent TeX distribution. – egreg Jan 19 '18 at 23:24