我尝试使用 tikz 将单个字母放置在箭头上方。但它似乎只适用于较长的文本。请参阅此 MWE:
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{arrows}
\usetikzlibrary{arrows.meta}
\begin{document}
% \tikz\draw[-implies,double equal sign distance] %<- works fine
% (0,0) -- node [above] {help} (1,0);
\tikz\draw[-implies,double equal sign distance] %<- doesn't work (lines are strange/missing)
(0,0) -- node [above] {hell} (1,0);
\end{document}
我究竟做错了什么?