我试图回答tikz-feynman：边缘标签当我遇到一个奇怪的问题时：
为什么第一个图有点像鸡蛋形状？没有左右的线条，它是圆的。请不要告诉我这是因为这个周末是复活节:)
% !TeX TS-program = lualatex
\documentclass{article}
\usepackage{tikz-feynman}
\begin{document}
\feynmandiagram[horizontal=b to d] {
a -- b,
b -- [quarter right]
c -- [quarter right]
d -- [quarter right]
e -- [quarter right]
b,
d -- f,
};
\feynmandiagram[horizontal=b to d] {
% a -- b,
b -- [quarter left]
c -- [quarter left]
d -- [quarter left]
e -- [quarter left]
b,
% d -- f,
};
\end{document}
我使用的软件包版本列表：
*File List*
article.cls 2018/09/03 v1.4i Standard LaTeX document class
size10.clo 2018/09/03 v1.4i Standard LaTeX file (size option)
tikz-feynman.sty 2016/02/05v1.1.0Feynman diagrams with TikZ
tikz.sty 2019/02/02 v3.1.1 (3.1.1)
pgf.sty 2019/02/02 v3.1.1 (3.1.1)
pgfrcs.sty 2019/02/02 v3.1.1 (3.1.1)
everyshi.sty 2001/05/15 v3.00 EveryShipout Package (MS)
pgfrcs.code.tex
pgfcore.sty 2019/02/02 v3.1.1 (3.1.1)
graphicx.sty 2017/06/01 v1.1a Enhanced LaTeX Graphics (DPC,SPQR)
keyval.sty 2014/10/28 v1.15 key=value parser (DPC)
graphics.sty 2009/02/05 v1.0o Standard LaTeX Graphics (DPC,SPQR)
trig.sty 2016/01/03 v1.10 sin cos tan (DPC)
graphics.cfg 2016/06/04 v1.11 sample graphics configuration
luatex.def 2018/01/08 v1.0l Graphics/color driver for luatex
pgfsys.sty 2019/02/02 v3.1.1 (3.1.1)
pgfsys.code.tex
pgfsyssoftpath.code.tex 2019/02/02 v3.1.1 (3.1.1)
pgfsysprotocol.code.tex 2019/02/02 v3.1.1 (3.1.1)
xcolor.sty 2016/05/11 v2.12 LaTeX color extensions (UK)
color.cfg 2016/01/02 v1.6 sample color configuration
pgfcore.code.tex
pgfcomp-version-0-65.sty 2019/02/02 v3.1.1 (3.1.1)
pgfcomp-version-1-18.sty 2019/02/02 v3.1.1 (3.1.1)
pgffor.sty 2019/02/02 v3.1.1 (3.1.1)
pgfkeys.sty
pgfkeys.code.tex
pgfmath.sty
pgfmath.code.tex
pgffor.code.tex
tikz.code.tex
ifluatex.sty 2016/05/16 v1.4 Provides the ifluatex switch (HO)
pgfopts.sty 2014/07/10 v2.1a LaTeX package options with pgfkeys
supp-pdf.mkii
epstopdf-base.sty 2016/05/15 v2.6 Base part for package epstopdf
infwarerr.sty 2016/05/16 v1.4 Providing info/warning/error messages (HO)
grfext.sty 2016/05/16 v1.2 Manage graphics extensions (HO)
kvdefinekeys.sty 2016/05/16 v1.4 Define keys (HO)
ltxcmds.sty 2016/05/16 v1.23 LaTeX kernel commands for general use (HO)
kvoptions.sty 2016/05/16 v3.12 Key value format for package options (HO)
kvsetkeys.sty 2016/05/16 v1.17 Key value parser (HO)
etexcmds.sty 2016/05/16 v1.6 Avoid name clashes with e-TeX commands (HO)
pdftexcmds.sty 2018/09/10 v0.29 Utility functions of pdfTeX for LuaTeX (HO)
ifpdf.sty 2018/09/07 v3.3 Provides the ifpdf switch
epstopdf-sys.cfg 2010/07/13 v1.3 Configuration of (r)epstopdf for TeX Live
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