Using LuaLaTeX + a custom font ... How to let (non-spaced) Chinese characters break across lines

Question

This question has a follow-up question, namely: "Change letter-spacing / tracking for punctuation marks (luatexja-fontspec)".

Imagine you are working in LuaLaTeX, and you want to use Chinese texts (often featuring long series of characters without spaces) to break across lines, so that the end-user can actually still read them. How would you do this?

According to an answer to the OP "How to use Chinese with lualatex?", one can simply use:

\usepackage{luatexja-fontspec}

However. This seems to overrule the use of a user-specified font, as would normally be customized by:

\setmainfont{...}

So my question is, in LuaLaTeX, how to both be able to:

• specify a custom font for the whole document,
• let the Chinese text line-break so as to make it readable?

MWE (to be compiled with LuaLaTeX)

\documentclass[a4paper, fontsize=30pt]{scrreprt}

\usepackage{fontspec}
\setmainfont{HanWangKaiMediumChuIn_wp010-08}

\begin{document}

勞碌奔波、勉強應付。《京本通俗小說．錯斬崔寧》：「光陰迅速，大娘子在家巴巴結結，將近一年，父親見他守不過，便叫家裡老王去接他來。」也作「巴巴急急」、「巴巴劫劫」、「波波劫劫」、「劫劫巴巴」、「劫劫波波」、「結結巴巴」。

\end{document}

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• Note: This MWE uses a custom font, namely HanWangKaiMediumChuIn_wp010-08.ttf, so one needs to to download it and install it in case one wishes to use the same.

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P.S.: According to the luatexja-package documentation, changing the default fonts should be possible (e.g. using \def\ltj@stdmcfont{psft:...}), but I have not been able to do so. Perhaps this option is restricted to fonts which are part of the luatexja-package?

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P.P.S: \usepackage{seqsplit} (see e.g. this answer to the OP "Automatic line breaking of long lines of text?") also doesn't seem to work for Chinese text.

Answer 1

I don't have your font. But with another one \setmainjfont works fine. The spacing between the glyph can be extended with \ltjsetparameter{kanjiskip=...} (see 4.2 kanjiskip and xkanjiskip in the documentation):

\documentclass[a4paper, fontsize=30pt]{scrreprt}
\usepackage{luatexja-fontspec}
\setmainjfont{Microsoft YaHei}

\begin{document}
勞碌奔波、勉強應付。《京本通俗小說．錯斬崔寧》：「光陰迅速，大娘子在家巴巴結結，將近一年，父親見他守不過，便叫家裡老王去接他來。」也作「巴巴急急」、「巴巴劫劫」、「波波劫劫」、「劫劫巴巴」、「劫劫波波」、「結結巴巴」。


\ltjsetparameter{kanjiskip=20pt}
勞碌奔波、勉強應付。《京本通俗小說．錯斬崔寧》：「光陰迅速，大娘子在家巴巴結結，將近一年，父親見他守不過，便叫家裡老王去接他來。」也作「巴巴急急」、「巴巴劫劫」、「波波劫劫」、「劫劫巴巴」、「劫劫波波」、「結結巴巴」。

\end{document}