EN:Horizontal

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Modern Horizontal Typesetting (\usepackage{luatex-cn})

\usepackage{luatex-cn} implements horizontal Chinese typesetting per the W3C Requirements for Chinese Text Layout (clreq) — it is the unified entry point of the whole bundle: in package form the default is horizontal, while vertical books use the ltc-guji / ltc-cn-vbook document classes. It is a package, not a document class: load it on top of any horizontal class (article, book, report, …) and it inserts kinsoku penalties and adjustable glue in pre_linebreak_filter / post_linebreak_filter.

The internal package name of the horizontal implementation is luatex-cn-hori; loading it directly still works, and the unified entry passes its options through verbatim. \usepackage[vertical]{luatex-cn} loads the vertical bundle instead (the historical 0.3.x semantics).

The rule kernel lives in tex/shared/ (the full clreq punctuation table, a one-dimensional priority space allocator, and the four-level kinsoku module) and is shared with the vertical engine — one source of truth for both writing modes.

Prerequisites

• Requires LuaTeX (lualatex); other engines abort with an error.
• Mutually exclusive with luatexja. ctex loads luatexja under LuaLaTeX; both insert CJK spacing and line-break penalties in the same callbacks, so loading both double-processes every paragraph. The package detects this and errors out. Use one or the other.
• Declare Chinese fonts through fontspec with Script=CJK and Language. Without them luaotfload starts from latn/dflt, whose locl substitutes a baseline-hugging Western ellipsis and never upgrades the dash to its full-width Chinese form.

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Minimal example

\documentclass[12pt]{article}
\usepackage[paperwidth=10cm, paperheight=16cm, margin=1.2cm]{geometry}
\usepackage{fontspec}
\setmainfont{Source Han Serif SC}[Script=CJK, Language={Chinese Simplified}]
\usepackage{luatex-cn}
\begin{document}
中文与 Western text 混排时，中西之间会自动插入四分之一字宽的可调间距。
\end{document}

Taiwan style (centered punctuation):

\usepackage[style=taiwan]{luatex-cn}

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Package options

Options may be given at \usepackage[...]{luatex-cn} time, or changed mid-document with \horiSetup{...} (CN alias \横排设置{...}); changes take effect for subsequent paragraphs.

Punctuation and spacing

Key	Values	Default	Description
style	mainland / taiwan / none	mainland	Punctuation style preset. mainland hugs the start edge with the blank at the end; taiwan centers the glyph; none is the clreq "no adjustment" preset (neither squeezed nor hugging)
cjk-latin-space	boolean	true	1/4 em space between CJK and Western text (shrinks to 1/8, stretches to 1/2; the three clreq exceptions get none)
inter-cjk-stretch	em ratio	0.05	Inter-CJK stretch of last resort
adjacent-punct	1.5 / 1 / natural	1.5	Consecutive-punctuation reduction. clreq requires adjacent bracket-type marks to go from 2 em to 1.5 em "in any style"; 1 reduces further to 1 em; natural squeezes only as line tightness demands
line-start-bracket	trim / natural	trim	Trim half a character from the start side of an opening bracket at line start (including an indented first line)
line-end-punct	compress / natural	compress	Half-width line-final punctuation (clreq compression level 1). compress always reclaims the blank and redistributes it; natural reclaims only as far as the line's tightness demands
hanging-punct	boolean	false	Hang line-final period-type marks outside the text area. Off by default because centered HK/TW marks should not hang
quote-style	keep / auto / curly / corner	keep	Quotation-mark convention conversion. keep leaves the manuscript untouched; auto follows style; curly (simplified horizontal: double outside, single inside) and corner (traditional Taiwan: single outside, double inside) are explicit, with nesting depth preserved by a one-to-one mapping

Line breaking and in-line distribution

Key	Values	Default	Description
kinsoku-level	none / basic / gb / strict	basic	Kinsoku strictness; clreq recommends basic
line-adjust	boolean	true	Per-line priority redistribution (clreq: 7 compression levels / 2 stretch levels, with an even-spread fallback)

Paragraphs and pages

Key	Values	Default	Description
paragraph-indent	length / keep	2em	First-line indent; clreq specifies the width of two Han characters. Resolved against the main font at \begin{document}; keep leaves \parindent alone
orphan-char	boolean	true	Avoid a single Han character alone on a paragraph's last line by borrowing from the previous line
last-line	left / center / right / justify	left	Last-line alignment. clreq says body paragraphs' last lines are not justified (the left default); use justify for lists, table captions, and other places where consistency is wanted
widow-penalty	integer	10000	Widow penalty (10000 = forbidden)
club-penalty	integer	10000	Club (orphan line) penalty

Interlinear annotations

Key	Values	Default	Description
ruby-size	ratio	0.5	Annotation size relative to the base text
ruby-gap	em ratio	0.1	Gap between the annotation row and the base row

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Commands

Setup

\horiSetup{last-line=right}      % CN alias: \横排设置

Interlinear indication marks (H3)

Single-sided binding convention: marks are drawn below the text.

Command	Alias	Effect
\专名{...}	—	Proper-name mark (straight underline)
\书名号甲{...}	\书名甲	Book-title mark, form A (wavy underline)
\着重{...}	—	Emphasis dots (placed below the line level)

太史公\专名{司马迁}著\书名号甲{史记}，其文\着重{究天人之际，通古今之变}。

• Adjacent proper names are drawn separately, not merged into one rule.
• Emphasis dots are never placed under punctuation.
• clreq requires a line gap of at least 0.5 em for interlinear marks; below that the marks touch the next line's glyphs. The package warns once on the first violation — raise the leading (e.g. \linespread{1.6}).

Interlinear annotations / phonetic guides (H4)

\ruby{base}{annotation}      % CN aliases: \拼音, \对照

\拼音{中国}{zhōng guó}的\拼音{汉字}{hàn zì}历史悠久；
\对照{印刷}{printing}术的发明意义重大。

• The annotation splits on spaces into syllables and is word-aligned with the base per clreq.
• The shorter row is spread across the block width (half a slot at each edge); the longer row is set solid.
• Size and gap come from ruby-size / ruby-gap.

Even spread

Distributes characters evenly across a given width with both ends flush — for titles, table cells, and the like.

\均排{目录}                 % defaults to \linewidth; alias \EvenSpread
\均排[6em]{凡例}

Line-level even distribution as a stretch fallback is handled by the line-adjust allocator; you do not need \均排 for that.

Paragraph styles (H5)

\begin{凸排}                % optional argument = hanging indent, default 2em
First line flush, subsequent lines indented — dictionary entries, bibliographies.
\end{凸排}

\begin{段落缩排}            % optional arguments: left, right indent (2em / 0pt)
The whole paragraph indented from the text area — quotations and editorial notes.
\end{段落缩排}

Traditional size numbers

The 号数 size system from clreq's "font size" section, shared between horizontal and vertical modes.

{\字号{三号} A level-3 heading\par}
{\字号{小四}[1.7] Body text with 1.7× leading\par}

The optional argument is the leading multiplier; omitted, it takes the shared-layer constant. Available sizes:

Name	pt	Name	pt	Name	pt
初号	42	二号	22	五号	10.5
小初	36	小二	18	小五	9
一号	26	三号	16	六号	7.5
小一	24	小三	15	小六	6.5
		四号	14	七号	5.5
		小四	12	八号	5

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Relationship to vertical mode

Horizontal and vertical share the clreq rule kernel in tex/shared/, so punctuation classification, kinsoku levels, and consecutive-punctuation reduction are one implementation. The five keys of \标点设置 — style, squeeze-mode, adjacent-punct, line-start-bracket, line-end-punct — use the same names and values as this package, and \字号 works in both modes.

Conformance testing

test/clreq_test.py parses the horizontal PDF content stream and asserts clreq clauses against measured glyph x-coordinates and advances: CJK–Western spacing bounds, no space beside period-type marks or inside bracket marks, line-start/line-end kinsoku, symbol-separation prohibition, two-em punctuation units, half-width line-final punctuation, interlinear annotation word alignment, and more. Every assertion cites its clreq clause, and the suite runs in CI.

python3 test/clreq_test.py                 # check the regression-test hori.tex
python3 test/clreq_test.py yourfile.tex    # check your own horizontal document

Example

論辯的魂靈 by Lu Xun — the same essay set twice: traditional with style=taiwan (centered punctuation), simplified with style=mainland + quote-style=curly (corner quotes converted to curly ones). Demonstrates consecutive-punctuation reduction, line-start/end compression, orphan-character avoidance, and last-line=right for the colophon.

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👉 See also: Punctuation ｜ Fonts ｜ cn-vbook / tw-vbook