答案1
您可以定义自己的新箭头类型=retro>
,如以下 MWE 所示。可以使用手册第 9 节中所述的前两个可选参数添加箭头上方和下方的文本chemfig
。
\documentclass{article}
\usepackage{chemfig}
\catcode`\_=11
\definearrow3{=retro>}{%
\CF_arrowshiftnodes{#3}%
\draw[double distance=2pt, -Implies] (\CF_arrowstartnode)--(\CF_arrowendnode);
\expandafter[\CF_arrowcurrentstyle](\CF_arrowstartnode)--(\CF_arrowendnode);%
\CF_arrowdisplaylabel{#1}{0.5}+\CF_arrowstartnode{#2}{0.5}-\CF_arrowendnode
}
\catcode`\_=8
\begin{document}
\schemestart
A \arrow{=retro>} B
\schemestop
\schemestart
A \arrow{=retro>[above][below]} B
\schemestop
\end{document}
chemfig
MWE 可与 1.4 版之前的版本兼容:
\documentclass{article}
\usepackage{chemfig}
\makeatletter
\definearrow3{=retro>}{%
\CF@arrow@shift@nodes{#3}%
\draw[double distance=2pt, -Implies] (\CF@arrow@start@node)--(\CF@arrow@end@node);
\expandafter[\CF@arrow@current@style](\CF@arrow@start@node)--(\CF@arrow@end@node);%
\CF@arrow@display@label{#1}{0.5}+\CF@arrow@start@node{#2}{0.5}-\CF@arrow@end@node
}
\makeatother
\begin{document}
\schemestart
A \arrow{=retro>} B
\schemestop
\schemestart
A \arrow{=retro>[above][below]} B
\schemestop
\end{document}