1 %#!lualatex ajt-devel-ltja
4 %%% Packages used in this paper
6 %%% Font setting for \LuaTeX; this is extract from ajt.cls
9 \RequirePackage{fontspec,xunicode}
10 \RequirePackage{luatextra}
11 \setmainfont[Mapping=tex-text]{Palatino LT Std}
12 \setsansfont[Mapping=tex-text]{Optima LT Std}
14 \RequirePackage{fontspec,luatextra}
15 \setmainfont[Mapping=tex-text]{TeX Gyre Pagella} % \simeq Palatino
19 \usepackage{luatexja,luatexja-fontspec}
20 \ltjsetparameter{jacharrange={-3,-8}}
21 \DeclareFontShape{JY3}{mc}{m}{n}{<-> s*[0.92489] file:ipam.ttf:jfm=ujis}{}
22 \DeclareFontShape{JY3}{gt}{m}{n}{<-> s*[0.92489] file:ipag.ttf:jfm=ujis}{}
23 % quick hack: monospaced Japanese font by \ttfamily
24 \DeclareKanjiFamily{JY3}{\ttdefault}{}{}
25 \DeclareFontShape{JY3}{\ttdefault}{m}{n}{<-> s*[0.92489] file:ipag.ttf:jfm=mono}{}
28 %%% LTXexample environment
29 \usepackage{showexpl,lltjlisting}
30 \lstset{basicstyle=\ttfamily\small, width=0.3\textwidth, basewidth=.5em}
32 %%% Verbatim environment
34 \CustomVerbatimEnvironment{code}{Verbatim}%
35 {numbers=left,xleftmargin=1.5em,baselinestretch=1.069,fontsize=\small}
36 \CustomVerbatimEnvironment{codewithoutnum}{Verbatim}%
37 {xleftmargin=1.5em,baselinestretch=1.069,fontsize=\small}
38 \CustomVerbatimEnvironment{codewithoutnumsmall}{Verbatim}%
39 {xleftmargin=1.5em,baselinestretch=1.0,fontsize=\footnotesize}
43 \usepackage{mflogo,booktabs}
44 \definecolor{grayx}{gray}{0.85}
50 %%% Mandatory article metadata %%%
51 \title{Development of \LuaTeX-ja package}
52 \author[北川 弘典]{Hironori Kitagawa}
53 \address{\LuaTeX-ja project team}
54 \email{h\_kitagawa2001@yahoo.co.jp}
56 \keywords{\TeX, p\TeX, \LuaTeX, \LuaTeX-ja, Japanese}
58 \LuaTeX-ja package is a macro package for typesetting Japanese
59 documents under \LuaTeX. The package has more flexibility of
60 typesetting than \pTeX, which is widely used Japanese extension of \TeX,
61 and has corrected some unwanted features of \pTeX.
62 In this paper, we describe specifications, the current status and some
63 internal processing methods of \LuaTeX-ja.
66 \newcommand{\parname}[1]{\textsf{#1}}
67 \newcommand{\jstrut}{\vrule width0pt height\cht depth\cdp}
68 \newcommand{\imagfm}[1]{\ifvmode\leavevmode\fi%
69 \hbox{\fboxsep=0pt\fbox{\setbox0=\hbox{#1}\copy0\kern-\wd0
70 \smash{\vrule width \wd0 height 0.4pt depth0.4pt}}}}
73 %%% Do not forget to start with \maketitle!
76 \section{Introduction}
78 To typeset Japanese documents with \TeX, ASCII \pTeX~\cite{ptex} has
79 been widely used in Japan. There are other methods---for example, using
80 Omega and OTP~\cite{omega}, or with the CJK package---to do so, however,
81 these alternative methods did not become majority. The author thinks
82 that this is because \pTeX\ enables us to produce high-quality documents
83 (e.g.,~supporting vertical typesetting), and the appearance of \pTeX\ is
84 earlier than that of alternatives described above.
86 However, \pTeX\ has been left behind from the extensions of \TeX\ such
87 as \eTeX\ and \pdfTeX, and the diffusion of UTF-8 encoding. In recent
88 years, the situation has become better, by development of
89 |ptexenc|~\cite{ptexenc} by Nobuyuki Tsuchimura (\hbox{土村展之}),
90 $\varepsilon$-\pTeX~\cite{eptex} by the author,~and u\pTeX~\cite{uptex}
91 by Takuji Tanaka (田中琢爾). However, continuing this approach, namely,
92 to develop an engine extension localized for Japanese, is not wise. This
93 approach needs lots of work for \emph{each} engine. In addition, if we
94 use \LuaTeX, the necessity of an engine extension is getting smaller
95 because \LuaTeX\ has an ability to hook \TeX's internal process by using
99 There were several experimental attempts to typeset
100 Japanese documents with \LuaTeX\ before. Here we cite three examples:
102 \item |luaums.sty|~\cite{luaums} developed by the author. This
103 experimental package is for creating a certain Japanese-based presentation
105 \item the \emph{luajalayout} package~\cite{luajalayout}, formerly known as the
106 \emph{jafontspec} package, by Kazuki Maeda (前田一貴). This package is based on
107 \LaTeXe\ and \emph{fontspec} package.
108 \item the \emph{luajp-test} package~\cite{luajp-test}, a test package made by
109 Atsuhito Kohda (香田温人), based on articles on the web page~\cite{joylua}.
111 However, these packages are based on \LaTeXe, and do not have much
112 ability to control the typesetting rule. And it is inefficient that more
113 than one people separately develop similar packages. Development of the
114 \LuaTeX-ja package is started initially by the author and Kazuki Maeda, because of
117 \subsection{Development policy of \LuaTeX-ja}
119 The first aim of \LuaTeX-ja project was to implement features (from the
120 `primitive' level) of \pTeX\ as macros under \LuaTeX, therefore \LuaTeX-ja is
121 much affected by \pTeX. However, as development proceeded, some
122 technical/conceptual difficulties arose. Hence we changed the aim
123 of the project as follows:
125 \item\emph{\LuaTeX-ja offers at least the same flexibility of
126 typesetting that p\TeX\ has.}
128 We are not satisfied with the ability of producing outputs conformed to
129 JIS~X~4051~\cite{jisx4051}, the Japanese Industrial Standard for
130 typesetting, or to a technical note~\cite{w3c} by W3C;
131 if one wants to produce very incoherent outputs for some reason, it
133 In this point, previous attempts of Japanese typesetting with \LuaTeX\
134 which we cited in the previous subsection are inadequate.
136 \pTeX\ has some flexibility of typesetting, by changing internal
137 parameters such as |\kanjiskip| or |\prebreakpenalty|, and by using
138 custom JFM (Japanese TFM). Therefore we decided to include these
139 functionality to \LuaTeX-ja.
141 \item\emph{\LuaTeX-ja isn't mere re-implementation or porting of \pTeX;
142 some (technically and/or conceptually) inconvenient features of
143 \pTeX\ are modified.}
145 We describe this point in more detail at the next section.
149 \subsection{Overview of the processes}
151 We describe an outline of \LuaTeX-ja's process in order.
154 \item In the |process_input_buffer| callback: treatment of breaking
155 lines after a Japanese character (in Subsection~\ref{ssec-line}).
157 \item In the |hyphenate| callback: font replacement.
159 \LuaTeX-ja looks into for each \textit{glyph\_node}~$p$ in the horizontal list. If
160 the character represented by $p$ is considered as a Japanese
161 character, the font used at $p$ is replaced by the value of
162 |\ltj@curjfnt|, an attribute for `the current Japanese font'
165 Furthermore, the subtype of $p$ is subtracted by 1 to suppress
166 hyphenation around $p$ by \LuaTeX, because later processes of
167 \LuaTeX-ja take care of all things about Japanese characters.
169 \item In |pre_linebreak_filter| and |hpack_filter| callbacks:
172 \item \LuaTeX-ja has its own stack system, and the current horizontal
173 list is traversed in this stage to determine what the level of
174 \LuaTeX-ja's internal stack at the end of the list is. We will
175 discuss it in Subsection~\ref{ssec-stack}.
177 \item In this stage, \LuaTeX-ja inserts glues/kerns for Japanese
178 typesetting in the list. This is the core routine of \LuaTeX-ja.
179 We will discuss it in Subsections
180 \ref{ssec-jglue}~and~\ref{ssec-jspec} .
182 \item To make a match between a metric and a real font, sometimes
183 adjustument of the position of (Japanese) glyphs are performed.
184 We will discuss it in Subsection~\ref{ssec-width}.
186 \item In the |mlist_to_hlist| callback: treatment of Japanese characters
187 in math formulas. This stage is similar to adjustment of the
188 position of glyphs (see above), so we omit to describe this stage
192 In this paper, a \emph{alphabetic character} means a non-Japanese
193 character. Similarly, we use the word an \emph{alphabetic font} as the
194 counterpart of a jJpanese font.
196 \subsection{Contents of this paper}
197 Here we describe the contents of the rest of this paper briefly. In
198 Section~\ref{sec:differences_with_ptex}, we describe major differences
199 between \pTeX\ and \LuaTeX-ja. The next section,
200 Section~\ref{sec:distinction_of_characters}, is concentrated on a
201 problem how we distinguish between Japanese characters and alphabetic
202 characters. In Section~\ref{sec:current_status}, we show current
203 development status of the package. Finally, in
204 Section~\ref{sec:implementation}, we describe some internal routines of
207 \subsection{General information of the project}
208 This \LuaTeX-ja project is hosted by SourceForge.jp. The official wiki
210 \url{http://sourceforge.jp/projects/luatex-ja/wiki/}. There is
211 no stable version on October 22, 2011, however a set of developer sources can be
212 obtained from the git repository. Members of the project team are as follows
213 (in random order): Hironori Kitagawa, Kazuki Maeda, Takayuki Yato,
214 Yusuke Kuroki, Noriyuki Abe, Munehiro Yamamoto, Tomoaki Honda,
218 \section{Major differences with \pTeX}
219 \label{sec:differences_with_ptex}
220 In this section, we explain several major differences between \pTeX\
221 and our \LuaTeX-ja. For general information of Japanese typesetting and the
222 overview of \pTeX, please see Okumura~\cite{ptexjp}.
225 \subsection{Names of control sequences}
226 \label{ssec-csname} Because \pTeX\ is an engine modification of Knuth's
227 original \TeX82 engine, some of the additional primitives take a form that is
228 very difficult to be simulated by a macro. For example, an additional
229 primitive |\prebreakpenalty|$\langle\hbox{\it
230 char\_code}\rangle$|[=]|$\langle\hbox{\it penalty}\rangle$ in \pTeX\
231 sets the amount of penalty inserted before a character whose code is
232 $\langle\hbox{\it char\_code}\rangle$ to $\langle\hbox{\it
233 penalty}\rangle$, and this form |\prebreakpenalty|$\langle\hbox{\it
234 char\_code}\rangle$ can be also used for retrieving the value.
236 Moreover, there are some internal parameters of \pTeX\ which values of them at the end of a
237 horizontal box or that of a paragraph are valid in whole box or
238 paragraph. However, the implementation of these parameters in
239 \LuaTeX-ja is not so easy; we will discuss it in Subsection~\ref{ssec-stack}.
241 From above two problems discussed above, the assignment and retrieval
242 of most parameters in \LuaTeX-ja are summarized into the following
243 three control sequences:
245 \item |\ltjsetparameter{|$\langle\hbox{\it
246 name}\rangle$|=|$\langle\hbox{\it value}\rangle$|,...}|: for local
248 \item |\ltjglobalsetparameter|: for global assignment. Note that these two control
249 sequences obey the value of |\globaldefs| primitive.
250 \item |\ltjgetparameter{|$\langle\hbox{\it
251 name}\rangle$|}[{|$\langle\hbox{\it optional
252 argument}\rangle$|}]|: for retrieval. The returned value is always
256 \subsection{Line-break after a Japanese character}
259 Japanese texts can break lines almost everywhere, in contrast with
260 alphabetic texts can break lines only between words (or use
261 hyphenation). Hence, \pTeX's input processor is modified so that a
262 line-break after a Japanese character doesn't emit a space. However,
263 there is no way to customize the input processor of \LuaTeX, other than
264 to hack its CWEB-source. All a macro package can do is to modify an input line before
265 when \LuaTeX\ begin to process it, inside the |process_input_buffer|
268 Hence, in \LuaTeX-ja, a comment letter (we reserve U+FFFFF for this
269 purpose) will be appended to an input line, if this line ends with a Japanese
270 character.\footnote{Strictly speaking, it also requires that the catcode
271 of the end-line character is 5~(\emph{end-of-line}). This condition is
272 useful under the verbatim environment.} One might jump to a conclusion
273 that the treatment of a line-break by \pTeX\ and that of \LuaTeX-ja are
274 totally same, however they are different in the respect that \LuaTeX-ja's
275 judgement whether a comment letter will be appended the line is done
276 \emph{before} the line is actually processed by \LuaTeX.
278 Figure~\ref{fig-linebreak} shows an example of this situation; the
279 command at the first line marks most of Japanese characters as
280 `non-Japanese characters'. In other words, from that command onward, the
281 letter `あ' will be treated as an alphabetic character by
282 \LuaTeX-ja. Then, it is natural to have a space between `あ' and `y' in
283 the output, where the actual output in the figure does not so. This is
284 because `あ' is considered a Japanese character by \LuaTeX-ja,
285 when \LuaTeX-ja does the decision whether U+FFFFF will be added to the
291 \ltjsetparameter{jacharrange={-6}}xあ
294 \caption{A notable sample showing the treatment of a line-break after a
295 Japanese character.}\label{fig-linebreak}
298 \subsection{Separation between `real' fonts and metrics}
301 Traditionally, most Japanese fonts used in typesetting are not
302 proportional, that is, most glyphs have same size (in most cases,
303 square-shaped). Hence, it is not rare that the contents of different
304 JFMs are essentially same, and only differ in their names. For example,
305 |min10.tfm| and |goth10.tfm|, which are JFMs shipped with \pTeX\ for
306 seriffed \emph{mincho} family and sans-seriffed \emph{gothic} family,
307 differ their |FAMILY| and |FACE| only. Moreover, |jis.tfm| and
308 |jisg.tfm|, which is included in the \emph{jis} font metric, which is
309 used in \emph{jsclasses}~\cite{jsclasses} by Haruhiko Okumura (奥村晴彦),
310 are totally same as binary files. Considering this situation, we
311 decided to separate `real' fonts and metrics used for them in
312 \LuaTeX-ja. Typical declarations of Japanese fonts in the style of plain
313 \TeX\ are shown in Figure~\ref{fig-jfdef}. We would like to add several
316 \item A control sequence |\jfont| must be used for Japanese fonts, instead of |\font|.
317 \item \LuaTeX-ja automatically loads the \emph{luaotfload} package, so
318 \hbox{\tt file:} and \hbox{\tt name:} prefixes, and various font features can be
319 used as the first line in Figure~\ref{fig-jfdef}.
320 \item The |jfm| key specifies the metric for the font. In
321 Figure~\ref{fig-jfdef}, both fonts will use a metric stored in a
322 Lua script named |jfm-ujis.lua|. This metric is the standard
323 metric in \LuaTeX-ja, and is based on JFMs used in the \emph{otf}
325 \item The \hbox{psft:} prefix can be used to specify name-only, non-embedded
326 fonts. When one displays a pdf with these fonts, actual fonts which
327 will be used for them depend on a pdf reader.
329 The specification of a metric for \LuaTeX-ja is similar to that of a JFM
330 (see \cite{ptexjp}); characters are grouped into several classes, the
331 size information of characters are specified for each class, and
332 glue/kern insertions are specified for each pair of classes. Although
333 the author have not tried, it may be possible to develop a program that
334 `converts' a JFM to a metric for \LuaTeX-ja. \LuaTeX-ja offers three
335 metrics by default; |jfm-ujis.lua|, |jfm-jis.lua| based on the
336 \emph{jis} font metric, and |jfm-min.lua| based on old |min10.tfm|.
338 Note that |-kern| in features
339 is important, because kerning information from a real font itself will
340 clash with glue/kern information from the metric.
344 \jfont\foo=file:ipam.ttf:jfm=ujis;script=latn;-kern;+jp04 at 12pt
345 \jfont\bar=psft:Ryumin-Light:jfm=ujis at 10pt
347 \caption{Typical declarations of Japanese fonts.}
351 \subsection{Insertion of glues/kerns for Japanese typesetting: timing}
354 As described in \cite{luatexref}, \LuaTeX's kerning and ligaturing
355 processes are totally different from those of \TeX82. \TeX82's process is
356 done just when a (sequence of) character is appended to the current
357 list. Thus we can interrupt this process by writing as
358 |f{}irm|. However, \LuaTeX's process is \emph{node-based}, that is, the
359 process will be done when a horizontal box or a paragraph is ended, so
360 |f{}irm| and |firm| yield same outputs under \LuaTeX.
362 The situation for Japanese characters is more complicated.
363 Glues (and kerns) which are needed for Japanese
364 typesetting are divided into the following three categories:
366 \item Glue (or kern) from the metric of Japanese fonts (\emph{JFM glue},
369 \item Default glue between a Japanese character and an alphabetic
370 character (\emph{xkanjiskip}, for short), usually 1/4 of
371 full-width (\emph{shibuaki}) with some stretch and shrink for
372 justifying each line.
373 \item Default glue between two consecutive Japanese characters
374 (\emph{kanjiskip}, for short). The main reason of this glue is to
375 enable breaking lines almost everywhere in Japanese texts. In most
376 cases, its natural width is zero, and some stretch/shrink for
377 justifying each line.
379 In \pTeX, these three kinds of glues are treated differently. A JFM glue
380 is inserted when a (sequence of) Japanese character is appended to the
381 current list, same as the case of alphabetic characters in \TeX82. This
382 means that one can interrupt the insertion process by saying |{}|. A
383 \emph{xkanjiskip} is inserted just before `hpack' or line-breaking of a
384 paragraph; this timing is somewhat similar to that of \LuaTeX's kerning
385 process. Finally, A \emph{kanjiskip} is not appeared as a node anywhere;
386 only appears implicitly in calculation of the width of a horizontal box,
387 that of breaking lines, and the actual output process to a DVI
388 file. These specifications have made \pTeX's behavior very hard to
391 \LuaTeX-ja inserts glues in all three categories simultaneously inside
392 |hpack_filter| and |pre_linebreak_filter| callbacks. The reasons of
393 this specification are to behave like alphabetic characters in \LuaTeX\
394 (as described in the first paragraph in this subsection), and to clarify
395 the specification for \LuaTeX-ja's process.
397 \subsection{Insertion of glues/kerns for Japanese typesetting: specification}
401 \caption{Examples of differences between \pTeX\ and \LuaTeX-ja.}
404 \begin{tabular}{llllllll}
406 &\multicolumn{1}{c}{(1)}&\multicolumn{1}{c}{(2)}&\multicolumn{1}{c}{(3)}&\multicolumn{1}{c}{(4)}\\
407 Input &|あ】{}【〕\/〔| &|い』\/a| &|う)\hbox{}(| &|え]\special{}[|\\\midrule
408 \pTeX &あ】\hbox{}【〕\hbox{}〔&い』\/a &う)\hbox{}( &え]\hbox{}[\\
409 \LuaTeX-ja &あ】{}【〕\/〔 &い』\/a &う)\hbox{}( &え]\special{}[\\
417 \fontsize{40}{40}\selectfont
419 \imagfm{\jstrut 】\inhibitglue}%
420 \imagfm{\jstrut\kern.5\zw}%
421 \imagfm{\jstrut\kern.5\zw}%
422 \imagfm{\jstrut\inhibitglue【}%
423 \imagfm{\jstrut 〕\inhibitglue}%
424 \imagfm{\jstrut\kern.5\zw}%
425 \imagfm{\jstrut\kern.5\zw}%
426 \imagfm{\jstrut\inhibitglue〔}%
428 \caption{Detail of the output of \pTeX\ in the input~(1) in Table~\ref{tab-jfmglue}.}
432 Now we will take a look at the insertion process itself through four points.
436 As noted in the previous subsection, the insertion process in \pTeX\ can
437 be interrupted by saying |{}| or anything else.\footnote{This
438 is why some tricks like \texttt{ちょ\char`\{\char`\}っと} for
439 \texttt{min10.tfm} and other `old' JFMs work.} This leads the
440 second row in Table~\ref{tab-jfmglue}, or
441 Figure~\ref{fig-ptexjfm}. Here `the process is interrupted'
442 means that \pTeX\ does not think the letter `】\inhibitglue'
443 is followed by `\inhibitglue【', hence two half-width glues
444 are inserted between `】\inhibitglue' and `\inhibitglue【',
445 where the left one is from `】\inhibitglue' and the right one
446 is from `\inhibitglue【'.
448 On the other hand, in \LuaTeX-ja, the process is done inside
449 |hpack_filter| and |pre_linebreak_filter| callbacks. Hence,
450 \emph{anything that does not make any node will be
451 ignored}\ in \LuaTeX-ja, as shown in (1) in
452 Table~\ref{tab-jfmglue}. \LuaTeX-ja also ignores any nodes
453 which does not make any contribution to current horizontal
454 list---\emph{ins\_node}, \emph{adjust\_node},
455 \emph{mark\_node}, \emph{whatsit\_node} and
456 \emph{penalty\_node}---, as shown in (4).
459 By the way, around a \emph{glyph\_node} $p$ there may be some nodes
460 attached to~$p$. These are an accent and kerns for
461 moving it to the right place, and a kern from the italic
462 correction\footnote{\TeX82 (and \LuaTeX) does not distinguish
463 between explicit kern and a kern for italic correction. To
464 distinguish them, an additional subtype for a kern is introduced
465 in \pTeX. On the other hand, \LuaTeX-ja uses an additional attribute and
466 redefines \texttt{\char`\\/} to set this attribute.} for $p$. It is natural that
467 these attachments should be ignored inside the process. Hence
468 \LuaTeX-ja takes this approach, as the latest version of
469 \pTeX\ (version~p3.2). This explains (2) in the Table~\ref{tab-jfmglue}.
471 Summerizing above, one should put an empty horizontal box |\hbox{}| to
472 where he/she wants to interrupt the insertion process in
473 \LuaTeX-ja as (3) in the Table~\ref{tab-jfmglue}.
475 \item[Fonts with the same metric]
476 Recall that \LuaTeX-ja separates `real' fonts and metrics, as in Subsection~\ref{ssec-sepmet}.
477 Consider the following input, where all Japanese fonts use same metric
478 (in \LuaTeX-ja), and |\gt| selects \emph{gothic} family for
479 the current Japanese font family:
485 If the above input is processed by \pTeX, because the insertion process is
486 interrupt by |\gt|, the result looks like
488 \mc 明朝)\hbox{}\gt (ゴシック
490 However this seems to be unnatural, since two Japanese fonts in the
491 output use the same metric, i.e.,~the same
492 typesetting rule. Hence, we decided that Japanese fonts with
493 the same metric are treated as one font in the insertion
494 process of \LuaTeX-ja. Thus, the output from the above input
495 in \LuaTeX-ja looks like:
499 One might have the situation that this default behavior is not
500 suitable. \LuaTeX-ja offers a way to handle this situation, but
501 we leave it to the manual~\cite{man}.
503 \item[Fonts with different metrics]
504 The case where two consecutive Japanese characters use different metrics and/or
505 different size is similar. Consider the following input where
506 the \emph{mincho} family and the \emph{gothic} family use
513 As the previous paragraph, this input yields the following, by \pTeX:
515 \mc 漢)\hbox{}\gt (漢)\hbox{}\large (大
517 We had thought that amounts of spaces between parentheses in above output
518 are too much. Hence we have changed the default behavior of
519 \LuaTeX-ja, so that the amount of a glue between two Japanese
520 characters with different metrics is the \emph{average} of a glue
521 from the left character and that from the right
522 character. For example, Figure~\ref{fig-diffmet} shows the
523 output from above input. The width of glue indicated `(1)' is
524 $(a/2 + a/2)/2 = 0.5a$, and the width of glue indicated `(2)'
525 is $(a/2 + 1.2a/2)/2 = 0.55a$. This default behavior can be
526 changed by \textsf{diffrentmet} parameter of \LuaTeX-ja.
530 \fontsize{40}{40}\selectfont
531 \imagfm{\jstrut\smash{%
532 \vtop{\lineskiplimit=\maxdimen\lineskip2pt\halign{#\cr漢\cr
533 \small\vrule height .5ex depth .5ex\hrulefill\ \lower.5ex\hbox{$a$}\
534 \hrulefill\vrule height .5ex depth .5ex\cr}}}}%
535 \imagfm{\jstrut )\inhibitglue}%
536 \hbox to .5\zw{\hss\normalsize (1)\hss}%
537 \imagfm{\jstrut\inhibitglue\gt (}%
538 \imagfm{\jstrut\gt 漢}%
539 \imagfm{\jstrut\gt )\inhibitglue}%
540 \hbox to .55\zw{\hss\normalsize (2)\hss}%
541 \imagfm{\fontsize{48}{48}\selectfont\jstrut\gt\inhibitglue (}%
542 \imagfm{\fontsize{48}{48}\selectfont\jstrut\smash{%
543 \vtop{\lineskiplimit=\maxdimen\lineskip2pt\halign{#\cr\gt 大\cr
544 \small\vrule height .5ex depth .5ex\hrulefill\ \lower.5ex\hbox{$1.2a$}\
545 \hrulefill\vrule height .5ex depth .5ex\cr}}}}
547 \caption{Fonts with different metrics.}
551 \item[\emph{kanjiskip} and \emph{xkanjiskip}]
552 In \pTeX, the value of \emph{xkanjiskip} is controlled by a skip named
553 |\xkanjiskip|. A well-known defect of this implementation is
554 that the value of \emph{xkanjiskip} is not connected with the
555 size of the currnt Japanese font. It seems that |EXTRASPACE|,
556 |EXTRASTRETCH|, |EXTRASHRINK| parameters in a JFM are
557 reserved for specifying the default value of
558 \emph{xkanjiskip} in a unit of the design size, but \pTeX\
559 did not use these parameters, actually.
561 Considering this situation of p\TeX, \LuaTeX-ja can use the value of
562 \emph{xkanjiskip} that specified in a metric. If the value of
563 \emph{xkanjiskip} on user side (this is the value of
564 \textsf{xkanjiskip} parameter of |\ltjsetparameter|) is
565 |\maxdimen|, then \LuaTeX-ja use the specification from
566 the current used metric as the actual value of
567 \emph{xkanjiskip}. This description also applies for \emph{kanjiskip}.
570 \section{Distinction of characters}
571 \label{sec:distinction_of_characters} Since \LuaTeX\ can handle Unicode
572 characters natively, it is a major problem that how we distinguish
573 Japanese characters and alphabetic characters. For example, the
574 multiplication sign (U+00D7) exists both in ISO-8859-1 (hence in Latin-1
575 Supplement in Unicode) and in the basic Japanese character set
576 JIS~X~0208. It is not desirable that this character is always treated as
577 an alphabetic character, because this symbol is often used in the sense
578 of `negative' in Japan.
580 \subsection{Character ranges}
581 Before we describe the approach taken is \LuaTeX-ja, we review the
582 approach taken by u\pTeX. u\pTeX\ extends the |\kcatcode| primitive in
583 \pTeX, to use this primitive for setting how a character is treated
584 among alphabetic characters~(15), \emph{kanji}~(16), \emph{kana}~(17),
585 \emph{kanji}, \emph{Hangul}~(17), or~\emph{other CJK characters}~(18).
586 The assignment to |\kcatcode| can be done by a Unicode
587 block.\footnote{There are some exceptions. For example, U+FF00--FFEF
588 (Halfwidth and Fullwidth Forms) are divided into three blocks in recent
591 \LuaTeX-ja adopted a different approach. There are many Unicode blocks
592 in Basic Multilingual Plane which are not included in
593 Japanese fonts, therefore it is inconvenient if we process by a Unicode
594 block. Furthermore, JIS~X~0208 are not just union of Unicode
595 blocks; for example, the intersection of JIS~X~0208 and
596 Latin-1 Supplement is shown in
597 Table~\ref{tab-inter}. Considering these two points, to
598 customize the range of Japanese characters in \LuaTeX-ja, one
599 has to define ranges of character codes in his source in advance.
603 \caption{Intersection of JIS~X~0208 and Latin-1 Supplement.}
606 \begin{tabular}{llll}
607 \ltjjachar"A7 (U+00A7),&
608 \ltjjachar"A8 (U+00A8),&
609 \ltjjachar"B0 (U+00B0),&
610 \ltjjachar"B1 (U+00B1),\\
611 \ltjjachar"B4 (U+00B4),&
612 \ltjjachar"B6 (U+00B6),&
613 \ltjjachar"D7 (U+00D7),&
614 \ltjjachar"F7 (U+00F7)
620 We note that \LuaTeX-ja offers two additional control sequences,
621 |\ltjjachar| and |\ltjalchar|. They are similar to |\char|
622 primitive, however |\ltjjachar| always yields a Japanese character, provided that
623 the argument is more than or equal to 128, and |\ltjalchar| always
624 yields an alphabetic character, regardless of the argument.
626 \subsection{Default setting of ranges}
627 Patches for plain \TeX\ and \LaTeXe\ of \LuaTeX-ja predefine 8~character
628 ranges, as shown in Table~\ref{tab-chrrng}. Almost of these ranges are
629 just the union of Unicode blocks, and determined from the Adobe-Japan1-6
630 character collection~\cite{aj16}, and JIS~X~0208. Among these 8~ranges,
631 the ranges~2, 3, 6, 7, and~8 are considered ranges of Japanese
632 characters, and others are considered ranges of alphabetic
633 characters.\footnote{Note that ranges 3~and~8 are considered ranges of
634 alphabetic characters in this paper.} We remark on ranges 2~and~8:
637 JIS~X~0208 includes Greek letters and Cyrillic letters, however, these
638 letters cannot be used for typesetting Greek or Russian, of
639 course. Hence it is reasonable that Greek letters and
640 Cyrillic consist another character range.
642 If one want to use 8-bit TFMs, such as T1 or TS1 encodings, he should
643 mark this range~8 as a range of alphabetic characters by
645 |\ltjsetparameter{jacharrange={-8}}|
647 This is because some 8-bit TFMs have a glyph in this range; for example,
648 the character `\OE' is located at |"D7| in the T1 encoding. %"
653 \caption{Predefined ranges in \LuaTeX-ja.}
656 \begin{tabular}{@{\bf}rl}
657 1&(Additional) Latin characters which are not belonged in the range~8.\\
658 2&Greek and Cyrillic letters.\\
659 3&Punctuations and miscellaneous symbols.\\
660 4&Unicode blocks which does not intersect with Adobe-Japan1-6.\\
661 5&Surrogates and supplementary private use Areas.\\
662 6&Characters used in Japanese typesetting.\\
663 7&Characters possibly used in CJK typesetting, but not in Japanese.\\
664 8&Characters in Table~\ref{tab-inter}.
669 \subsection{Control sequences producing Unicode characters}
672 The \emph{fontspec} package\footnote{Preciously saying, it is the
673 \emph{xunicode} package, originally a package for \XeTeX and
674 automatically loaded by the \emph{fontspec} package.} offers various
675 control sequences that produce Unicode characters. However, these
676 control sequences as it stands cannot work correctly with the default
677 range setting of \LuaTeX-ja. For example, |\textquotedblleft| is just
678 an abbreviation of |\char"201C\relax|, and the character U+201C (LEFT %"
679 DOUBLE QUOTATION MARK) is treated as an Japanese character, because it
680 belongs to the range~3. This problem is resolved by using |\ltjalchar|
681 instead of the |\char| primitive. It is included in an optional package
682 named \texttt{luatexja-\penalty0fontspec.sty}. Figure~\ref{fig-unitxt}
683 shows several ways o typeset a character , both as a Japanese character
684 and as as an alphabetic characters.
688 ×, \char`×, % depend on range setting
689 \ltjalchar`×, % alphabetic char
690 \ltjjachar`×, % Japanese char
691 \texttimes % alph. char (by fontspec)
693 \caption{Control sequences producing a Unicode character.}
697 The situation looks similar in math formulas, but in fact it differs.
698 Each control sequence that represents an ordinary symbol defined by the
699 \emph{unicode-math} package is just synonym of a character. For example,
700 the meaning of |\otimes| is just the character U+2297 (CIRCLED TIMES),
701 which is included in the range~3. However, it is difficult to define a
702 control sequence like |\ltjalUmathchar| as a counterpart of
703 |\Umathchar|, since an input like `|\sum^\ltjalUmathchar ...|' has to be
706 However, we couldn't develop a satisfactory solution to this problem in
707 time for this paper, due to a lack of time. We are just testing a
710 \item \LuaTeX-ja has a list of character codes which will be always reated as
711 alphabetic characters in math mode. Considering 8-bit TFMs for
712 math symbols, this list includes natural numbers between |"80| and
714 \item Redefine internal commands defined in the \emph{unicode-math}
716 codes of characters which are mentioned in the \emph{unicode-math}
717 package will be included in the list.
721 We would like to extend treatments described in this subsection to 8-bit
722 font encodings, but we leave it to further development too.
724 \section{Current status of development}
725 \label{sec:current_status}
726 At the moment, \LuaTeX-ja can be used under plain \TeX, and under
727 \LaTeXe. Generally speaking, one only has to read |luatexja.sty|, by
728 |\input| command or |\usepackage| (in~\LaTeXe), if you merely want to
729 typeset Japanese characters. We look more detail by parts.
731 \subsection{`Engine extension'}
732 The lowest part of \LuaTeX-ja corresponds to the \pTeX\ extension as
733 \emph{an engine extension of \TeX}. We, the project menbers, think that
734 this part is almost done. There is one more feature of \LuaTeX-ja which
735 we are going to explain:
738 \item[Shifting baseline]
739 In order to make a match between Japanese fonts and alphabetic fonts,
740 sometimes shifting the baseline of alphabetic characters may
741 be needed. \pTeX\ has a dimension |\ybaselineshift|, which
742 corresponds to the amount of shifting down the baseline of alphabetic
743 characters. This is useful for Japanese-based documents, but
744 not for documents mainly in languages with alphabetic
747 Hence, \LuaTeX-ja extends \pTeX's |\ybaselineshift| to Japanese
748 characters. Namely, \LuaTeX-ja offers two parameters,
749 \textsf{yjabaselineshift} and \textsf{yalbaselineshift}, for the
750 amount of shifting the baseline of Japanese characters and
751 that of alphabetic characters, respectively.
754 \fontsize{40}{40}\selectfont\fboxsep0mm
755 \vrule width 0.9\textwidth height0.4pt depth0.4pt\kern-0.9\textwidth
756 \hbox to 0.9\linewidth{%
758 \raise-10pt\imagfm{\jstrut 漢}%
759 \raise-10pt\imagfm{\jstrut 字}\hskip.25\zw%
764 \imagfm{\jstrut 字}\hskip.25\zw%
765 \raise-10pt\imagfm{p}%
766 \raise-10pt\imagfm{h}%
771 \caption{First example of shifting baseline.}
777 \fontsize{30}{30}\selectfont\fboxsep0mm
778 \vrule width 0.9\textwidth height0.4pt depth0.4pt\kern-0.9\textwidth
779 \hbox to 0.9\linewidth{%
782 \imagfm{b}\hskip.25\zw%
784 \imagfm{\jstrut 文}\hskip.33333\zw%
785 \raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont\jstrut\inhibitglue (}%
786 \raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont\jstrut 注}%
787 \raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont\jstrut 釈}\hskip.1666667\zw%
788 \raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont c}%
789 \raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont o}%
790 \raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont m}%
791 \raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont m}%
792 \raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont e}%
793 \raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont n}%
794 \raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont t}%
795 \raise3.514582pt\imagfm{\fontsize{20}{20}\selectfont\jstrut )\inhibitglue}%
803 \caption{Second example of shifting baseline.}
807 An example output is shown in Figure~\ref{fig-bls}. The left half is the
808 output when \textsf{yjabaselineshift} is positive, hence the
809 baseline of Japanese characters is shifted down. On the other
810 hand, the right half is the output when
811 \textsf{yalbaselineshift} is positive, hence the baseline of
812 alphabetic characters is shifted down. Figure~\ref{fig-small}
813 shows an intresting use of these parameters.
816 Note that \LuaTeX-ja doesn't support vertical typesetting, \emph{tategaki}, for now.
818 \subsection{Patches for plain \TeX\ and \LaTeXe}
819 \pTeX\ has a patch for plain \TeX, namely |ptex.tex|, that for \LaTeXe\
820 macro (this patch and \LaTeXe\ consist \emph{p\LaTeXe}), and
821 |kinsoku.tex| which includes the default setting of \emph{kinsoku
822 shori}, the Japanese hyphenation. We ported them to \LuaTeX-ja, except
823 the codes related to vertical typesetting, because \LuaTeX-ja doesn't
824 support vertical typesetting yet. We remark one point related to the
828 \item[Behavior of\/ {\tt\char92fontfamily\/}]
829 The control sequence |\fontfamily| in p\LaTeXe\ changes the current alphabetic
830 font family and/or the current Japanese font family,
831 depending the argument. More concretely,
832 |\fontfamily{|$\langle\hbox{\it arg\/}\rangle$|}| changes the
833 current alphabetic font family to $\langle\hbox{\it
834 arg\/}\rangle$, if and only if one of the following
835 conditions are satisfied:
837 \item An alphabetic font family named $\langle\hbox{\it arg\/}\rangle$ in
838 \emph{some} alphabetic encoding is already defined in the document.
839 \item There exists an alphabetic encoding $\langle\hbox{\it
840 enc\/}\rangle$ already defined in the document such that a font
841 definition file $\langle\hbox{\it enc\/}\rangle\langle\hbox{\it
842 arg\/}\rangle$|.fd| (all lowercase) exists.
844 The same criterion is used for changing Japanese font family.
846 To work this behavior well, a list of all (alphabetic) encodings defined
847 already in the document is needed. However, since \LuaTeX-ja
848 is loaded as a package, \LuaTeX-ja cannot have this list.
849 Hence \LuaTeX-ja adopted a different approach, namely
850 |\fontfamily{|$\langle\hbox{\it arg\/}\rangle$|}| changes the
851 current alphabetic font family to $\langle\hbox{\it
852 arg\/}\rangle$, if and only if:
854 \item An alphabetic font family named $\langle\hbox{\it arg\/}\rangle$
855 in the current alphabetic encoding $\langle\hbox{\it
856 enc\/}\rangle$ is already defined in the document.
857 \item A font definition file $\langle\hbox{\it enc\/}\rangle\langle\hbox{\it
858 arg\/}\rangle$|.fd| (all lowercase) exists.
866 \subsection{Classes for Japanese documents}
867 To produce `high-quality' Japanese documents, we need not only that
868 Japanese characters are correctly placed, but also class files for
869 Japanese documents. Two major families of classes are widely used in Japan:
870 \emph{jclasses} which is distributed with the official p\LaTeXe\ macros,
871 and \emph{jsclasses}. At the present, \LuaTeX-ja
872 simply contains their counterparts: \emph{ltjclasses} and
873 \emph{ltjsclasses}. However, the policy on classes is not determined
874 now, and we hope to have another family of classes which are useful for
875 commercial printing. In the author's opinion, \emph{ltjclasses} is
876 better to stay as an example of porting of class files for \pTeX\ to
879 \subsection{Patches for packages}
880 Apart from patches for the \LaTeXe~kernel and classes for Japanese
881 documents, we need to make patches for several packages. At the present,
882 we considered the following packages, and made patches or porting for
883 the former two packages.
886 \item[The \emph{fontspec} package] The \emph{fontspec} package is built
887 on NFSS2, hence control sequences offered by the
888 \emph{fontspec} package, such as |\setmainfont|, are only
889 effective for alphabetic fonts if \LuaTeX-ja is loaded.
890 \texttt{luatexja-\penalty0fontspec.sty} (not automatically
891 loaded) offers these counterparts for Japanese fonts, with
892 additional `j' in the name of control sequences, such as
893 |\setmainjfont|. As described in
894 Subsection~\ref{ssec-unichar}, it also includes a patch for
895 control sequences producing Unicode characters.
897 \item[The \emph{otf} package]
898 This package is widely used in \pTeX\ for typesetting characters which is
899 not in JIS~X~0208, and for using more than one weight in \emph{mincho}
900 and \emph{gothic} font families. Therefore \LuaTeX-ja supports features
901 in the \emph{otf} package, by loading \texttt{luatexja-\penalty0otf.sty}
902 manually. Note that characters by |\UTF{xxxx}| and
903 |\CID{xxxx}| are not appended to the current list as a
904 \emph{glyph\_node}, to avoid from callbacks by the
905 \emph{luaotfload} package. We have another remark; |\CID|
906 does not work with TrueType fonts, since |\CID| use the
907 conversion table between CID and the glyph order of the
908 current Japanese font.
910 \item[The \emph{listings} package]
911 It is known for users of \pTeX\ that there is a patch |jlisting.sty| for
912 the \emph{listings} package, to use Japanese characters in
913 the |lstlisting| environment. Generally speaking, it also can
914 be used in \LuaTeX-ja. However, it seems to be that a
915 Japanese character after a space does not recieve any process
916 of the \emph{listings} package; this is inconvinient when we
917 use the \emph{showexpl} package.
919 There is another way to use characters above 256 with the
920 \emph{listings} package (described in\cite{apl}). However,
921 this method is not suitable for Japanese, since the number of
922 Japanese characters is very large. We hope that the
923 \emph{listings} package will be able to handle all characters above
924 256 without any patch, in the future.
931 \section{Implementation}
932 \label{sec:implementation}
933 \subsection{Handling of Japanese fonts}
934 In \pTeX, there are three slots for maintaining current fonts, namely
935 |\font| for alphabetic fonts, |\jfont| for Japanese fonts (in horizontal
936 direction) and |\tfont| for Japanese fonts (in vertical direction). With
937 these slots, we can manage the current font for alphabetic characters
938 and that for Japanese characters separately in \pTeX. However, \LuaTeX\
939 has only one slot for maintaining the current font, as \TeX82. This
940 situation leads a problem: how can we maintain the `current Japanese
943 There are three approaches for this problem. One approach is to make a
944 mapping table from alphabetic fonts to corresponding Japanese fonts
945 (here we don't assume that NFSS2 is available). Another approach is
946 that we always use composite fonts with alphabetic fonts and Japanese
947 fonts. The third approach is that the information of the current
948 Japanese font is stored in an attribute. We adopted the third approach,
949 since \LuaTeX-ja is much affected by \pTeX\ as we noted in
950 Subsection~\ref{ssec-pol}.
952 As in Figure~\ref{fig-jfdef}, \LuaTeX-ja uses |\jfont| for defining
953 Japanese fonts, as \pTeX. However, because the information of the current
954 Japanese font is stored into an attribute, control sequences defined by
955 |\jfont| (e.g.,~|\foo| and |\bar| in Figure~\ref{fig-jfdef}) is
956 not representing a font by the means of \TeX82. In other words, each of
957 these control sequences is just an assignment to an attribute, therefore
958 they cannot be an argument of |\the|, |\fontname|, nor |\textfont|.
961 Callbacks by the \emph{luaotfload} package, e.g.,~replacement of glyphs
962 according to OpenType font features, are performed just after `Examination of
963 stack level' (see Subsections
964 \ref{ssec-over}~and~\ref{ssec-stack}). Also note that calculation of
965 character classes for each Japanese character is done \emph{after} the
966 these callbacks for now.
968 \subsection{Stack management}
971 As we noted in Subsection~\ref{ssec-csname}, parameters that the values
972 at the end of a horizontal box or that of a paragraph are valid in
973 whole box or paragraph, such as \emph{kanjiskip}, cannot be implemented
974 by internal integers or registers of other types in \TeX. We explain it
985 if (cur_list.mode_field == -hmode) {
986 cur_box = filtered_hpack(cur_list.head_field,
987 cur_list.tail_field, saved_value(1),
988 saved_level(1), grp, saved_level(2));
989 subtype(cur_box) = HLIST_SUBTYPE_HBOX;
992 \caption{An extract of a CWEB-source \texttt{tex/packaging.w} of \LuaTeX.}
996 Figure~\ref{fig-ltsrc} is an extract of a CWEB-source
997 \texttt{tex/packaging.w} of \LuaTeX\ (SVN revision 4358). This function
998 is called just when an explicit |\hbox{...}| or |\vbox{...}| is ended, and
999 the function |filtered_hpack()| is where the |hpack_filter| and then the
1000 actual `hpack' process are performed. Notice that the |unsave()|
1001 function is called before |filtered_hpack()|. This is the problem;
1002 because of |unsave()|, we can retrive only the values of registers
1003 \emph{outside} the box, even in the |hpack_filter| callback.
1005 To cope with this problem, \LuaTeX-ja has its own stack system, based on
1006 Lua codes in \cite{stack-mail}. Furthermore, \emph{whatsit} nodes whose
1007 \emph{user\_id} is 30112 (\emph{stack\_node}, for short) will be
1008 appended to the current horizontal list each time the current stack
1009 level is incremented, and their values are the values of
1010 |\currentgrouplevel| at that time. In the beginning of the |hpack_filter|
1011 callback, the list in question is traversed to determine whether the
1012 stack level at the end of the list and that outside the box coincides.
1014 Let $x$ be the value of |\currentgrouplevel|, and $y$ be the current
1015 stack level, both inside the |hpack_filter| callback, i.e.,~outside a
1016 horizontal box. Consider a list which represents the content of the box,
1019 \item A \emph{stack\_node} whose value is $x+1$ (because all materials
1020 in the box are included in a group |\hbox{...}|, the value of
1021 |\currentgrouplevel| inside the box is at least $x+1$) in the list
1022 corresponds to an assignment related to the stack system in just
1023 top-level of the list, like
1026 \hbox{...(assignment)...}
1029 In this case, the current stack level is incremented to $y+1$ after the assignment.
1030 \item A \emph{stack\_node} whose value is more than $x+1$ in the list corresponds
1031 to an assignment inside another group contained in the box. For example,
1032 the following input creates
1033 a \emph{stack\_node} whose value is $x+3=(x+1)+2$:
1036 \hbox{...{...{...(assignment)}...}...}
1040 Thus, we can conclude that the stack level at the end of the list is
1041 $y+1$, if and only if there is a \emph{stack\_node} whose value is
1042 $x+1$. Otherwise, the stack level is just $y$.
1044 \subsection{Adjustment of the position of Japanese characters}
1047 The size of a glyph specified in a metric and that of a real font
1048 usually differ. For example, the letter `\inhibitglue【' is half-width
1049 in |jfm-ujis.lua| or |jis.tfm|, while this letter is full-width like `【'
1050 in most TrueType fonts used in Japanese typesetting, such as
1051 IPA~Mincho. Hence the adjustment of position of such glyphs is
1052 needed. In the context of \pTeX, this process was performed using virtual fonts.
1054 On the other hand, Lua\TeX-ja does the adjustment by encapsuling a glyph
1055 into a horizontal box. There are two main reasons why we adopted this
1056 method; one is that we feared Lua codes for coexisting with callbacks by
1057 the |luaotfload| package would be large if we use virtual fonts, and the
1058 other is to cope with shifting of the baseline of characters at the
1062 \begin{center}\unitlength=9pt\small
1063 \begin{picture}(15,12)(-1,-3)
1065 \color{grayx}% real glyph
1066 \put(-1,-1.5){\vrule width 6\unitlength height 7\unitlength depth 2.5\unitlength}
1068 \color{black}% real glyph :step1
1070 \put(-1,-1.5){\line(0,1){7}\line(0,-1){2.5}}
1071 \put(5,-1.5){\line(0,1){7}\line(0,-1){2.5}}
1072 \put(-1,5.5){\line(1,0){6}}
1073 \put(-1,-4){\line(1,0){6}}
1074 \put(-1,0){\makebox(0,0)[r]{\strut$R$\,}}
1077 \put(0,0){\vector(0,1){9}\line(0,-1){3}\vector(1,0){12}}
1078 \put(12,9){\makebox(0,0)[rt]{\strut$M$\,}}
1079 \put(12,0){\line(0,1){9}\vector(0,-1){3}}
1080 \put(0,9){\line(1,0){12}}
1081 \put(0,-3){\line(1,0){12}}
1082 \put(0.2,4.5){\makebox(0,0)[l]{\texttt{height}}}
1083 \put(12.2,-1.5){\makebox(0,0)[l]{\texttt{depth}}}
1084 \put(6,0.2){\makebox(0,0)[b]{\texttt{width}}}
1087 \put(3,0){\line(0,1){7}\line(0,-1){2.5}\line(1,0){6}}
1088 \put(9,0){\line(0,1){7}\line(0,-1){2.5}}
1089 \put(3,7){\line(1,0){6}}
1090 \put(3,-2.5){\line(1,0){6}}
1091 \newsavebox{\eqdist}
1092 \savebox{\eqdist}(0,0)[c]{%
1094 \put(-0.08,0.2){\line(0,-1){0.4}}%
1095 \put(0.08,0.2){\line(0,-1){0.4}}}
1096 \put(1.5,0){\usebox{\eqdist}}
1097 \put(10.5,0){\usebox{\eqdist}}
1100 \put(3,-1.5){\vector(-1,0){4}}
1101 \put(1,-1.7){\makebox(0,0)[t]{\texttt{left}}}
1102 \put(3,0){\vector(0,-1){1.5}}
1103 \put(3.2,-0.75){\makebox(0,0)[l]{\texttt{down}}}
1106 \caption{The position of the `real' glyph.}
1110 Figure~\ref{fig-pos} shows the adjustment process. A large square $M$ is
1111 the imaginary body specified in the metric, and a vertical
1112 rectangle is the imaginary body of a real glyph. First, the real glyph
1113 is aligned with respect to the width of $M$. In the figure, the real
1114 glyph is aligned `middle'; this setting is useful for the full-width
1115 middle dot `・'. We have other settings, `left' and `right'.
1116 After that, it is shifted according to the value of |left| and |down|,
1117 which are specified in the metric, too. The final position of the real glyph
1118 is shown by the gray rectangle~$R$. If the amount of shifting the baseline is
1119 not zero, $M$ (and hence the real glyph) is shifted by that amount.
1121 We would like to remark briefly on the vertical position of a real
1122 glyph. A JFM (or a metric used in \LuaTeX-ja) and a real font used for
1123 it may have different height or depth. In that case, it may look better
1124 if the real glyph is shifted vertically to match the height-depth ratio
1125 specified in the metric, while any vertical adjustment except the
1126 adjustment by the |down| value does not performed in the present
1127 implementation of \LuaTeX-ja . This situation is carefully studied by
1128 Otobe~\cite{min10}. Here the policy on this problem is not determined
1129 now, however we would like to offer several solutions in future
1132 \section{Conclusion}
1133 We have discussed about our \LuaTeX-ja package, which is much affected
1134 by \pTeX. For now, it can be used for experimental use, however there
1135 are much refinements which are needed for regular use. The author hopes
1136 that this paper and \LuaTeX-ja project contribute the typesetting Japanese,
1137 and possibly other Asian languages, under \LuaTeX.
1139 \section*{Acknowledgements}
1140 The author would like to thank Ken Nakano and Hideaki Togashi for their
1141 development of ASCII \pTeX. The author is very grateful to Haruhiko
1142 Okumura for his leadership in the Japanese \TeX\ community. The author
1143 is also very grateful to members of \LuaTeX-ja project team for their
1144 valuable cooperation in development.
1146 %%% The style of the bibiliogrphy is `amsplain'.
1147 \providecommand{\bysame}{\leavevmode\hbox to3em{\hrulefill}\thinspace}
1148 \providecommand{\href}[2]{#2}
1149 \begin{thebibliography}{99}
1152 Adobe Systems Incorporated, \emph{Adobe-Japan1-6 Character Collection
1153 for CID-Keyed Fonts}, Technical Note~\#5078, 2004.
1154 \url{http://partners.adobe.com/public/developer/en/font/5078.Adobe-Japan1-6.pdf}
1157 ASCII MEDIA WORKS,アスキー日本語\TeX\ (\pTeX).\url{http://ascii.asciimw.jp/pb/ptex/}
1160 John Baker, \emph{Typesetting UTF8 APL code with the \LaTeX\ lstlisting package}.
1161 \url{http://bakerjd99.wordpress.com/2011/08/15/}
1164 Jin-Hwan~Cho and Haruhiko Okumura, \emph{Typesetting CJK Languages with Omega},
1165 \TeX, XML, and Digital Typography, Lecture Notes in Computer Science, vol.~3130,
1166 Springer, 2004, 139--148.
1169 Yannis Haralambous. \emph{The Joy of \LuaTeX}. \url{http://luatex.bluwiki.com/}
1172 Japanese Industrial Standards Committee. \emph{JIS~X~4051: Formatting
1173 rules for Japanese documents}, 1993, 1995, 2004.
1176 北川弘典,$\varepsilon$-\pTeX についてのwiki.
1177 \url{http://sourceforge.jp/projects/eptex/wiki/FrontPage}
1181 \url{http://oku.edu.mie-u.ac.jp/tex/mod/forum/discuss.php?d=378}
1184 \LuaTeX\ development team, \emph{The \LuaTeX\ reference}.
1185 \url{http://www.luatex.org/svn/trunk/manual/luatexref-t.pdf} (snapshot of SVN trunk)
1188 \LuaTeX-ja project team, \emph{The \LuaTeX-ja package}.
1189 Not completed for now. Available at |doc/man-en.pdf| (in English) or
1190 |doc/man-ja.pdf| (in Japanese)
1191 in the Git repository.
1193 \bibitem{luajp-test}
1195 \url{http://www1.pm.tokushima-u.ac.jp/~kohda/tex/luatex-old.html}
1197 \bibitem{luajalayout}
1198 前田一貴,luajalayout パッケージ---Lua\LaTeX によ
1200 \url{http://www-is.amp.i.kyoto-u.ac.jp/lab/kmaeda/lualatex/luajalayout/}
1203 奥村晴彦,p\LaTeXe 新ドキュメントクラス.
1204 \url{http://oku.edu.mie-u.ac.jp/~okumura/jsclasses/}
1207 Haruhiko Okumura, \emph{\pTeX\ and Japanese Typesetting},
1208 The Asian Journal of \TeX\ \textbf{2}~(2008), 43--51.
1212 \url{http://argent.shinshu-u.ac.jp/~otobe/tex/files/min10.pdf}
1215 齋藤修三郎,Open Type Font用VF.
1216 \url{http://psitau.kitunebi.com/otf.html}
1218 \bibitem{stack-mail}
1219 Jonathan Sauer, \emph{[Dev-luatex] tex.currentgrouplevel}.
1220 \url{http://www.ntg.nl/pipermail/dev-luatex/2008-August/001765.html}
1223 Takuji Tanaka, \emph{u\pTeX, up\LaTeX---unicode version of \pTeX, p\LaTeX}.
1224 \url{http://homepage3.nifty.com/ttk/comp/tex/uptex_en.html}
1227 Nobuyuki Tsuchimura and Yusuke Kuroki, \emph{Development of Japanese \TeX\ Environment},
1228 The Asian Journal of \TeX\ \textbf{2}~(2008), 53--62.
1231 W3C Working Group, \emph{Requirements for Japanese Text Layout}.
1232 \url{http://www.w3.org/TR/jlreq/}
1233 \end{thebibliography}