LuaLaTeX - Pinyin over rare Chinese characters

Question

I know that using the xpinyin package can solve this, but I need to use Lualatex, which is not supported.

At first I used the following code:

\documentclass{ctexart}
\usepackage{amsmath}
\newcommand\zhuyin[2]{$\overset{\textrm{#1}}{#2}$}

\begin{document}
\zhuyin{tiān}{天}
\end{document}

For general Chinese characters, it works very well.

But now I have some rare characters that need to be annotated, they are in the Unicode Extension B area, which means that the normal font does not include them (I've tried fonts like Source Han Sans): 𧉍(U+2724D), 𧉆(U+27246). On my system, it seems that only simsunb.ttf can display them. I'm having trouble changing the font in mathematical mode. I tried the following code and it failed:

\documentclass{ctexart}
\usepackage{amsmath}
\newcommand\zhuyin[2]{$\overset{\textrm{#1}}{#2}$}
\newfontfamily{\zyextb}{simsunb.ttf}[NFSSFamily=simsunb]
\DeclareMathAlphabet{\mathzy}{TU}{simsunb}{m}{n}

\begin{document}
%I also tried \zhuyin{jí}{\zyextb 𧉆}
\zhuyin{jí}{\mathzy 𧉆}
\end{document}

Can you help me?

Answer 1

You can use luatexja-ruby package.

\documentclass{ctexart}
\usepackage{luatexja-ruby}
\newcommand\zhuyin[3][]{\ltjruby[{#1}]{#3}{#2}}
\newCJKfontfamily{\esimsun}{simsun.ttc}[NFSSFamily=esimsun,
  AlternateFont=
    {
      {"20000->"2FA1D}{simsunb.ttf}, 
%      {"30000->"323AF}{simsung.ttf}
    }]

\begin{document}

\zhuyin{tiān}{天}
\zhuyin{jí}{\esimsun 𧉆}

{\esimsun\zhuyin{tiān|jí}{天|𧉆}}

\end{document}

CJK characters are JAchar, and their fonts are different from ALchar's. \newfontfamily is using to set ALChar's font.

You can use AlternateFont key to set alternate fonts, so that this font command can switch to another font automatically.