\usepackage[utf8]{vietnam} 导致错误： \UTFviii@three@octets 的参数有一个额外的 }

Question

我有一个问题\usepackage[UTF8]{vietnam}。

\documentclass[clock,fragile]{beamer}
\usepackage{amsmath,amssymb,amsfonts, mathrsfs,bm,mathpazo}
%\usepackage{amsfonts,fouriernc}
\usepackage[utf8]{vietnam}
\usepackage{multicol,xcolor,animate,multimedia,tcolorbox}
\usepackage{enumerate,shadowtext}
\usepackage{tikz,tkz-tab,pgf}
\usetikzlibrary{arrows,decorations,decorations.pathmorphing,
shapes,decorations.text}
\usepackage{url, picinpar,graphicx,lipsum}
\usetheme{Darmstadt}
\usetheme{CambridgeUS}
\begin{document}
\begin{frame}[fragile]
\begin{tikzpicture}
[place/.style={circle,draw=blue!50,fill=blue!20,thick,
inner sep=0pt,minimum size=6mm,text width=2cm,align=center},
transition/.style={rectangle,draw=black!50,fill=black!20,thick,
inner sep=0pt,minimum size=4mm}]
\node at ( 0,0) [place] (Ap){Nhóm $ p $ - adic};
\node at ( 4,0) [place] (X){Continuum Peano};
%\node at ( 0,0) [place] {};
\node at ( 8,2.5) [place] (kq1){Phân hoạch đẳng biến};
\node at (8,-2.5) [place] (kq2){Đường cong Menger};
\draw [->] (Ap.east) -- (X.west) node [above,text width=3cm,align=center,midway]{tác động};
\draw [->] (X.north) to [bend left=30] (kq1.west) node [auto,swap]{hiệu} ;
\def\myshift#1{\raisebox{-2.5ex}}
\draw [->,line width=1.5pt,color=red,postaction={decorate,decoration={text along path,text align=center,text={|\myshift| Tự do}}}] (X.south) to [bend right=30] (kq2.west);
\end{tikzpicture}
\end{frame}
\end{document}

运行后pdflatex，出现! Argument of \UTFviii@three@octets has an extra }。如何修复？

Answer 1

以下示例通过将文本中有问题的 UTF-8 字符括起来来修复decorate：

text={|\myshift| T{ự} do}

否则，文本将被逐字节扫描，并破坏多字节 UTF-8 字符。