From: Hironori Kitagawa Date: Sat, 19 Nov 2011 02:23:54 +0000 (+0900) Subject: Updated the draft for post-proceedings; also included font setting in LuaTeX. X-Git-Url: http://git.osdn.jp/view?a=commitdiff_plain;h=3fc31d876eafc1446062cc19a1fd6bf9fc70a0b5;p=luatex-ja%2Fluatexja.git Updated the draft for post-proceedings; also included font setting in LuaTeX. --- diff --git a/doc/ajt-devel-ltja.tex b/doc/ajt-devel-ltja.tex index 15be69d..3c083d5 100644 --- a/doc/ajt-devel-ltja.tex +++ b/doc/ajt-devel-ltja.tex @@ -2,21 +2,32 @@ \documentclass{ajt} %%% Packages used in this paper -%%% LuaTeX-ja -\usepackage{luatexja} +%%% Font setting for \LuaTeX; this is extract from ajt.cls +\makeatletter + \if@print + \RequirePackage{fontspec,xunicode} + \RequirePackage{luatextra} + \setmainfont[Mapping=tex-text]{Palatino LT Std} + \setsansfont[Mapping=tex-text]{Optima LT Std} + \else + \RequirePackage{fontspec,luatextra} + \setmainfont[Mapping=tex-text]{TeX Gyre Pagella} % \simeq Palatino + \fi + +%%% LuaTeX-ja +\usepackage{luatexja,luatexja-fontspec} +\ltjsetparameter{jacharrange={-3,-8}} \DeclareFontShape{JY3}{mc}{m}{n}{<-> s*[0.92489] file:ipam.ttf:jfm=ujis}{} \DeclareFontShape{JY3}{gt}{m}{n}{<-> s*[0.92489] file:ipag.ttf:jfm=ujis}{} % quick hack: monospaced Japanese font by \ttfamily \DeclareKanjiFamily{JY3}{\ttdefault}{}{} \DeclareFontShape{JY3}{\ttdefault}{m}{n}{<-> s*[0.92489] file:ipag.ttf:jfm=mono}{} -%%% for LTXexample environment -\usepackage{showexpl,lltjlisting} -\lstset{basicstyle=\ttfamily\small, width=0.3\textwidth, basewidth=.5em} -\usepackage{mflogo,booktabs} -\definecolor{grayx}{gray}{0.85} +%%% LTXexample environment +\usepackage{showexpl,lltjlisting} +\lstset{basicstyle=\ttfamily\small, width=0.3\textwidth, basewidth=.5em} %%% Verbatim environment \usepackage{fancyvrb} @@ -28,6 +39,10 @@ {xleftmargin=1.5em,baselinestretch=1.0,fontsize=\footnotesize} \DefineShortVerb{\|} +%%% Others +\usepackage{mflogo,booktabs} +\definecolor{grayx}{gray}{0.85} + %%% Mandatory article metadata %%% \title{Development of the \LuaTeX-ja package} \author{Hironori Kitagawa {\normalsize 北川 弘典}} @@ -65,7 +80,7 @@ earlier than alternatives described above. However, p\TeX\ has been left behind from the extensions of \TeX\ such as \eTeX\ and \pdfTeX, and the diffusion of UTF-8 encoding. In -recent years, the situation become better, because of developments +recent years, the situation become better, because of development of |ptexenc|~\cite{ptexenc} by Nobuyuki Tsuchimura (\hbox{土村展之}), $\varepsilon$-p\TeX~\cite{eptex} by the author,~and up\TeX~\cite{uptex} by Takuji Tanaka (田中琢爾). However, continuing this approach, namely, to develop @@ -125,32 +140,74 @@ p\TeX\ has some flexibility of typesetting, by changing internal \end{itemize} +\subsection{Overview of the Processes} +\label{ssec-over} +We describe an outline of the \LuaTeX-ja's process in order. +\begin{itemize} +\item In the |process_input_buffer| callback: treatment of breaking + lines after a Japanese character (in Subsection~\ref{ssec-line}). + +\item In the |hyphenate| callback: font replacement. + +\LuaTeX-ja looks into for each \textit{glyph\_node}~$p$ in the list. If + the character represented by $p$ is considered as a Japanese + character, the font used in $p$ is replaced by the value of + |\ltj@curjfnt|, an attribute for `the current Japanese font' + at~$p$. + +Furthermore the subtype of $p$ is subtracted by 1 to suppress + hyphenation around it by \LuaTeX, because later processes of + \LuaTeX-ja take care of all things about Japanese characters. + +\item In |pre_linebreak_filter| and |hpack_filter| callbacks: + +\begin{enumerate} +\item \LuaTeX-ja has its own stack system, and the current horizontal + list is traversed in this stage to determine what is the level of + \LuaTeX-ja's internal stack at the end of the list (in + Subsection~\ref{ssec-stack}). + +\item In this stage, \LuaTeX-ja inserts glues/kerns for Japanese + typesetting in the list. This is the core of \LuaTeX-ja (in + Subsection~\ref{ssec-jglue}). + +\item To make a match between a metric and a real font, sometimes + adjustument of the position of (Japanese) glyphs are performed + (Subsection~\ref{ssec-width}). +\end{enumerate} +\item In the |mlist_to_hlist| callback: replacement of Japanese characters in math formulas. +This stage is similar to adjustument of the position of glyphs (see + above), so we omit it from this paper. +\end{itemize} + \subsection{Contents of this Paper} Here we describe the contents of the rest of this paper briefly. In Section~2, we describe major differences between p\TeX\ and \LuaTeX-ja. -In Section~3, we show the current status of the \LuaTeX-ja package. In -Section~4, we describe some internal routines of \LuaTeX-ja. We hope -that the materials in this section have good applications. +The next section, Section~3, is concentrated on a problem `how we +distinguish between Japanese characters and alphabetic characters'. In +Section~4, we show rest of features of the \LuaTeX-ja package, and +current status of the package. Finally, in Section~5, we describe some +internal routines of \LuaTeX-ja. \subsection*{About the Project} This \LuaTeX-ja project is hosted by SourceForge.jp. The official wiki is located on \url{http://sourceforge.jp/projects/luatex-ja/wiki/FrontPage}. There is -no stable version at Oct.\ 15, 2011, however the development source can be -obtained from the git repository. Members of the project are as follows +no stable version at Oct.\ 15, 2011, however the latest developer sources can be +obtained from the git repository. Members of the project team are as follows (in random order): Hironori Kitagawa, Kazuki Maeda, Takayuki Yato, Yusuke Kuroki, Noriyuki Abe, Munehiro Yamamoto, Tomoaki Honda, and~Shuzaburo Saito. \section{Major differences with \pTeX} -In this section, we look at several major differences between p\TeX\ +In this section, we explain several major differences between p\TeX\ and our \LuaTeX-ja. For general information of Japanese typesetting and the overview of p\TeX, please see Okumura~\cite{ptexjp}. \subsection{Names of Control Sequences} -\label{ssec-csname} Since p\TeX\ is an engine modification of Knuth's +\label{ssec-csname} Because p\TeX\ is an engine modification of Knuth's original \TeX82 engine, some primitives added by it take a form that is very difficult to be simulated by a macro. For example, an additional primitive |\prebreakpenalty|$\langle\hbox{\it @@ -265,7 +322,7 @@ metrics by default; |jfm-ujis.lua|, |jfm-jis.lua| based on the \emph{jis} font metric, and |jfm-min.lua| based on old |min10.tfm|. Note that |-kern| in features -is important, since kerning information from real font itself will +is important, because kerning information from real font itself will clash with glue/kern informations from the metric. \begin{figure} @@ -409,7 +466,7 @@ Consider the following input, where all Japanese fonts use same metric 明朝）\gt （ゴシック \end{verbatim} \end{quote} -If the above input is processed by p\TeX, since the insertion process is +If the above input is processed by p\TeX, because the insertion process is interrupt by |\gt|, the result looks like \begin{quote} \mc 明朝）\hbox{}\gt （ゴシック @@ -495,40 +552,173 @@ Considering this situation of p\TeX, \LuaTeX-ja can use the value of This description also applies for \emph{kanjiskip}. \end{description} +\section{Distinction of Characters} +Since \LuaTeX\ can handle Unicode characters natively, it is a major +problem that how we distinguish Japanese characters and alphabetic +characters. For example, the multiplication sign (U+00D7) exists both in +ISO-8859-1 (hence in Latin-1 Supplement in Unicode) and in the basic +Japanese character set JIS~X~0208. It is not desirable that this +character is treated as an alphabetic char, because this symbol is often +used in the sense of `negative' in Japan. + +\subsection{Character Ranges} +Before we describe the approach taken is \LuaTeX-ja, we review the +approach taken by up\TeX. up\TeX\ extends the |\kcatcode| primitive in +p\TeX, to use this primitive for setting how a character is treated +among alphabetic characters~(15), \emph{kanji}~(16), \emph{kana}~(17), +\emph{kanji}, \emph{Hangul}~(17), or~\emph{other CJK characters}~(18). +The assignment to |\kcatcode| can be done by a Unicode +block\footnote{There are some exceptions. For example, U+FF00--FFEF +(Halfwidth and Fullwidth Forms) are divided into three blocks in recent +up\TeX.}. + +\LuaTeX-ja adopted a different approach. There are many Unicode blocks + in Basic Multilingual Plane which are not included in + Japanese fonts, it is inconvenient if we treat by a Unicode + block. Furthermore, JIS~X~0208 are not just union of Unicode + blocks; for example, the intersection of JIS~X~0208 and + Latin-1 Supplement is shown in + Table~\ref{tab-inter}. Considering these two points, to + customize the range of Japanese characters in \LuaTeX-ja, one + has to define ranges of character codes in his source in advance. + + +\begin{table} +\caption{Intersection of JIS~X~0208 and Latin-1 Supplement.} +\label{tab-inter} +\begin{center} +\begin{tabular}{llll} +\ltjjachar"A7 (U+00A7),& +\ltjjachar"A8 (U+00A8),& +\ltjjachar"B0 (U+00B0),& +\ltjjachar"B1 (U+00B1),\\ +\ltjjachar"B4 (U+00B4),& +\ltjjachar"B6 (U+00B6),& +\ltjjachar"D7 (U+00D7),& +\ltjjachar"F7 (U+00F7) +\end{tabular} +\end{center} +\end{table} + +%%Example... + +We note that \LuaTeX-ja offers two additional control sequence, + |\ltjjachar| and |\ltjalchar|. They are similar to |\char| + primitive, but |\ltjjachar| always yields a Japanese character (if + the argument is more than or equal to 128) and |\ltjalchar| always + yields an alphabetic character, regardless of the argument. + +\subsection{Default Setting of Ranges} +Patches for plain \TeX\ and \LaTeXe of \LuaTeX-ja predefines 8~character +ranges, as shown in Table~\ref{tab-chrrng}. Almost of these ranges are +just the union of Unicode blocks, and determined from the Adobe-Japan1-6 +character collection~\cite{aj16}, and JIS~X~0208. Among these 8~ranges, +the ranges~2, 3, 6, 7, and~8 are considered ranges of Japanese +characters, and others are considered ranges of alphabetic +characters\footnote{Note that ranges 3~and~8 are considered ranges of +alphabetic characters in this paper.}. We remark on ranges 2~and~8: +\begin{description} +\item[The range~2] +JIS~X~0208 includes Greek letters and Cyrillic letters, however, these + letters cannot be used for typesetting Greek or Russian, of + course. Hence it is reasonable that Greek letters and + Cyrillic consist another character range. +\item[The range~8] +If one want to use 8-bit TFMs, such as T1 or TS1 encodings, he should + mark this range~8 as a range of alphabetic characters by +\begin{quote} +|\ltjsetparameter{jacharrange={-8}}| +\end{quote} +This is because some 8-bit TFMs have a glyph in this range; for example, + the character `\OE' is located at |"D7| in the T1 encoding. %" +\end{description} + + +\begin{table} +\caption{Predefined ranges in \LuaTeX-ja} +\label{tab-chrrng} +\begin{center} +\begin{tabular}{@{\bf}rl} +1&(Additional) Latin characters which are not belonged in the range~8.\\ +2&Greek and Cyrillic letters.\\ +3&Punctuations and miscellaneous symbols.\\ +4&Unicode blocks which does not intersect with Adobe-Japan1-6.\\ +5&Surrogates and supplementary private use Areas.\\ +6&Characters used in Japanese typesetting.\\ +7&Characters possibly used in CJK typesetting, but not in Japanese.\\ +8&Characters in Table~\ref{tab-inter}. +\end{tabular} +\end{center} +\end{table} + +\subsection{Control Sequences Producing Unicode Characters} +\label{ssec-unichar} + +The \emph{fontspec} package\footnote{Preciously +saying, it is the \emph{xunicode} package, originally a package for +\XeTeX and automatically loaded by the \emph{fontspec} package.} offer +various control sequences that produce Unicode characters. However, they as +it stands cannot work with the default range setting of \LuaTeX-ja. For +example, |\textquotedblleft| is just an abbreviation of +|\char"201C\relax| %" +and the character U+201C (LEFT DOUBLE QUOTATION +MARK) is treated as an Japanese character, because it belongs to the +range~3. +This problem is resolved by using |\ltjalchar| instead of the |\char| primitive. +It is included in an optional package named \texttt{luatexja-\penalty0fontspec.sty}. +Figure~\ref{fig-unitxt} ... + +\begin{figure} +\begin{LTXexample} +×, \char`×, % depend on range setting +\ltjalchar`×, % alphabetic char +\ltjjachar`×, % Japanese char +\texttimes % alph. char (by fontspec) +\end{LTXexample} +\caption{Control sequences producing a Unicode character} +\label{fig-unitxt} +\end{figure} + +The situation looks similar in math formulas, but in fact it differs. +Control sequences that represents ordinary symbols defined by the +\emph{unicode-math} package is just synonym of a character. For example, +the meaning of |\otimes| is just the character U+2297 (CIRCLED TIMES), +which is included in the range~3. However, it is difficult to define a +control sequence like |\ltjalUmathchar| as a counterpart of +|\Umathchar|, since an input like `|\sum^\ltjalUmathchar ...|' has to be +permitted. + +However, we couldn't include a solution to this problem in time for this +paper, due to a lack of time. We are just testing a solution that we +will explain it below: +\begin{itemize} +\item \LuaTeX-ja has a list of character codes which will be treated as + alphabetic characters in math mode. Considering 8-bit TFMs for + math symbols, this list includes natural numbers between |"80| and + |"FF| by default. +\item Redefine internal commands defined in the \emph{unicode-math} + package so that +codes of characters which are mentioned in the \emph{unicode-math} + package will be included in the list. +\end{itemize} + + +We would like to extend treatments described in this section to 8-bit +font encodings, but we leave it to further development too. \section{Current Status of Development} At the moment, \LuaTeX-ja can be used under plain \TeX, and under -\LaTeXe. Generally speaking, one only has to read |luatexja.sty|, by |\input| -command or |\usepackage| (in~\LaTeXe), if you merely want to typeset -Japanese characters. We look more detail by parts. +\LaTeXe. Generally speaking, one only has to read |luatexja.sty|, by +|\input| command or |\usepackage| (in~\LaTeXe), if you merely want to +typeset Japanese characters. We look more detail by parts. \subsection{`Engine Extension'} The lowest part of \LuaTeX-ja corresponds the p\TeX\ extension as \emph{an engine extension of \TeX}. We, the project menbers, think that -this part is almost done. Other features of \LuaTeX-ja which we have not -described are the followings: -\begin{description} -\item[Setting the Range of `Japanese characters'] This feature is - inspired by up\TeX. up\TeX\ has an additional primitive named - |\kcatcode| for setting how a character is treated among an - alphabetic character, \emph{kana}, \emph{kanji}, - \emph{Hangul}, or~\emph{an other CJK character}. and the - assignment of |\kcatcode| can be done by a Unicode - block\footnote{There are some exceptions. For example, - U+FF00--FFEF (Halfwidth and Fullwidth Forms) are divided into - three blocks in recent up\TeX.}. - -\LuaTeX-ja uses a slightly different approach. Because there are many - Unicode blocks already in Basic Multilingual Plane which are - not included in most Japanese fonts, so it would be - inefficient to toggle by a Unicode block. Furthermore, the - basic Japanese character set JIS~X~0208 are not just union of - Unicode blocks; for example, the intersection of JIS~X~0208 - and Latin-1 Supplement is shown in Table~\ref{tab-inter}. - Considering these two points, to customize the range of - Japanese characters in \LuaTeX-ja, one has to define - character ranges in his source in advance. +this part is almost done. There is one more feature of \LuaTeX-ja which +we are going to explain: +\begin{description} \item[Shifting Baseline] In order to make a match between Japanese fonts and alphabetic fonts, sometimes shifting the baseline of alphabetic characters may @@ -543,7 +733,6 @@ Hence, \LuaTeX-ja extends p\TeX's |\ybaselineshift| to Japanese \textsf{yjabaselineshift} and \textsf{yalbaselineshift}, for the amount of shifting the baseline of Japanese characters and that of alphabetic characters, respectively. - \begin{figure} \begin{center} \fontsize{40}{40}\selectfont\fboxsep0mm @@ -608,70 +797,17 @@ An example output is shown in Figure~\ref{fig-bls}. The left half is the shows an intresting use of these parameters. \end{description} -Note that \LuaTeX-ja doesn't support for vertical typesetting, \emph{tategaki}, for now. - -\begin{table} -\caption{Intersection of JIS~X~0208 and Latin-1 Supplement.} -\label{tab-inter} -\begin{center} -\begin{tabular}{llll} -\char"A7 (U+00A7),& -\char"A8 (U+00A8),& -\char"B0 (U+00B0),& -\char"B1 (U+00B1),\\ -\char"B4 (U+00B4),& -\char"B6 (U+00B6),& -\char"D7 (U+00B7),& -\char"F7 (U+00D7) -\end{tabular} -\end{center} -\end{table} +Note that \LuaTeX-ja doesn't support vertical typesetting, \emph{tategaki}, for now. \subsection{Patches for plain \TeX\ and \LaTeXe} p\TeX\ has a patch for plain \TeX, namely |ptex.tex|, that for \LaTeXe\ macro (this patch and \LaTeXe\ consist \emph{p\LaTeXe}), and |kinsoku.tex| which includes the default setting of \emph{kinsoku shori}, the Japanese hyphenation. We ported them to \LuaTeX-ja, except -the codes related to vertical typesetting, since \LuaTeX-ja doesn't -support vertical typesetting yet. We remark two points related to the +the codes related to vertical typesetting, because \LuaTeX-ja doesn't +support vertical typesetting yet. We remark one point related to the porting: \begin{description} -\item[Default Range of Japanese Characters] -As described in the previos subsection, \LuaTeX-ja can customize the -range of Japanese characters. \LuaTeX-ja predefines 8~character ranges, -as shown in Table~\ref{tab-chrrng}. Almost of these ranges are just the -union of Unicode blocks, and determined from the Adobe-Japan1-6 character -collection~\cite{aj16}, and JIS~X~0208. And, among these 8~ranges, the - ranges~2, 3, 6, 7, and~8 are considered ranges of Japanese - characters, and others are considered ranges of alphabetic - characters. - -This default setting is suitable for Japanese-based documents, however it - causes that other packages which use Unicode fonts do not work - correctly. For example, |\times| provided by the - |unicode-math| package is the character U+00D7, which belongs - to the range~8, and |\textendash| provided by the |EU2| - encoding used in the \emph{fontspec} package is the - character U+2013, which belongs to the range~3. hence, these - character cannot be typeset correctly with the default range setting. - -\begin{table} -\caption{Predefined ranges in \LuaTeX-ja} -\label{tab-chrrng} -\begin{center} -\begin{tabular}{@{\bf}rl} -1&(Additional) Latin characters which is not belonged in the range~8.\\ -2&Greek and Cyrillic letters.\\ -3&Punctuations and miscellaneous symbols.\\ -4&Unicode blocks which does not intersect with Adobe-Japan1-6.\\ -5&Surrogates and supplementary private use Areas.\\ -6&Characters used in Japanese typesetting.\\ -7&Characters possibly used in CJK typesetting, but not in Japanese.\\ -8&Characters in Table~\ref{tab-inter}. -\end{tabular} -\end{center} -\end{table} - \item[Behavior of\/ {\tt\char92fontfamily\/}] The control sequence |\fontfamily| in p\LaTeXe\ changes the current alphabetic @@ -687,7 +823,7 @@ The control sequence |\fontfamily| in p\LaTeXe\ changes the current alphabetic \item There exists an alphabetic encoding $\langle\hbox{\it enc\/}\rangle$ already defined in the document such that a font definition file $\langle\hbox{\it enc\/}\rangle\langle\hbox{\it - arg\/}\rangle$|.fd| exists. + arg\/}\rangle$|.fd| (all lowercase) exists. \end{itemize} The same criterion is used for changing Japanese font family. @@ -699,10 +835,11 @@ To work this behavior well, a list of all (alphabetic) encodings defined current alphabetic font family to $\langle\hbox{\it arg\/}\rangle$, if and only if: \begin{itemize} -\item An alphabetic font family named $\langle\hbox{\it arg\/}\rangle$ in - the current alphabetic encoding $\langle\hbox{\it enc\/}\rangle$. +\item An alphabetic font family named $\langle\hbox{\it arg\/}\rangle$ + in the current alphabetic encoding $\langle\hbox{\it + enc\/}\rangle$ already defined in the document. \item A font definition file $\langle\hbox{\it enc\/}\rangle\langle\hbox{\it - arg\/}\rangle$|.fd| exists. + arg\/}\rangle$|.fd| (all lowercase) exists. \end{itemize} @@ -733,11 +870,13 @@ the former two packages. \item[The \emph{fontspec} package] The \emph{fontspec} package is built on NFSS2, hence control sequences offered by the \emph{fontspec} package, such as |\setmainfont|, are only - effective for alphabetic fonts if \LuaTeX-ja is loaded. The - optional package \texttt{luatexja-\penalty0fontspec.sty} - offers these counterparts for Japanese fonts, with additional - `j' in the name of control sequences, such as - |\setmainjfont|. + effective for alphabetic fonts if \LuaTeX-ja is loaded. + \texttt{luatexja-\penalty0fontspec.sty} (not automatically + loaded) offers these counterparts for Japanese fonts, with + additional `j' in the name of control sequences, such as + |\setmainjfont|. As described in + Subsection~\ref{ssec-unichar}, it also includes a patch for + control sequences producing Unicode characters. \item[The \emph{otf} package] This package is widely used in p\TeX\ for characters which is @@ -782,52 +921,19 @@ since \LuaTeX-ja is much affected by p\TeX\ as we noted in Subsection~\ref{ssec-pol}. As in Figure~\ref{fig-jfdef}, \LuaTeX-ja uses |\jfont| for defining -Japanese font, as p\TeX. However, since the information of the current +Japanese font, as p\TeX. However, because the information of the current Japanese font is stored into an attribute, control sequences defined by |\jfont| (e.g.,~|\foo| and |\bar| in Figure~\ref{fig-jfdef}) is not representing a font by the means of \TeX82. In other words, each of these control sequences is just an assignment to an attribute, therefore -they cannot be an argument of |\the|, |\fontname|, or |\textfont|. - -\subsection{Overview of the Processes} -Now we describe an outline of the \LuaTeX-ja's process briefly. -\begin{description} -\item[Treatment of Line-breaks after a Japanese Character] This part is - described already in Subsection~\ref{ssec-line}. Done in the - |process_input_buffer| callback. -\item[Font Replacement] In the |hyphenate| callback, \LuaTeX-ja looks - into for each \textit{glyph\_node}~$p$ in the list. If the - character represented by $p$ is considered as a Japanese - character, the font used in $p$ is replaced by the value of - |\ltj@curjfnt|, `the current Japanese font' at~$p$. Also the - character class of the character is looked up at this time. +they cannot be an argument of |\the|, |\fontname|, nor |\textfont|. -Furthermore the subtype of $p$ is subtracted by 1 to suppress - hyphenation around it by \LuaTeX, since later processes of - \LuaTeX-ja take care of all things about Japanese characters. -\end{description} -% -Following processes are all executed in |pre_linebreak_filter| and -|hpack_filter| callback. These processes are main routines of \LuaTeX-ja. - -\begin{description} -\item[Examination of Stack Level] The horizontal list which - is the content of a horizontal box is traversed, -to determine what is the level of \LuaTeX-ja's internal stack at the end - of the list. This is needed because of the place of - the |hpack_filter| callback in the source of \LuaTeX. We will discuss more - detail in Subsection~\ref{ssec-stack}. - -\item[Insertion of Glues/Kerns for Japanese Typesetting] -This part is already described at Subsection~\ref{ssec-jglue}. - -\item[Adjustument of the Position of (Japanese) Characters] -We will discuss the detail about this in Subsection~\ref{ssec-width}. -\end{description} -The callbacks by the \emph{luaotfload} package, e.g.,~replacement of -glyphs according to font features, are executed just after `Examination -of Stack Level' above. +Callbacks by the \emph{luaotfload} package, e.g.,~replacement of glyphs +according to font features, are executed just after `Examination of +Stack Level' (see Subsection~\ref{ssec-over}). Note that calculation of +character classes for each Japanese character is done \emph{after} the +these callbacks for now. \subsection{Stack Management} \label{ssec-stack} @@ -880,7 +986,7 @@ stack level, both inside the |hpack_filter| callback, i.e.,~outside a horizontal box. Consider a list which represents the content of the box, then we have: \begin{itemize} -\item A \emph{stack\_node} whose value is $x+1$ (since all materials in +\item A \emph{stack\_node} whose value is $x+1$ (because all materials in the box are included in a group |\hbox{...}|, the value is at least $x+1$) in the list represents an assignment related to the stack system in just top-level of the list, like @@ -907,7 +1013,7 @@ $x+1$. Otherwise, the stack level is just $y$. \subsection{Adjustment of the Position of Japanese Characters} \label{ssec-width} -The size of a glyph specified in a metric and that of the real font +The size of a glyph specified in a metric and that of a real font usually differ. For example, the letter `\inhibitglue【' is half-width in |jfm-ujis.lua| or |jis.tfm|, while this letter is full-width like `【' in most TrueType fonts used in Japanese typesetting, such as @@ -916,9 +1022,9 @@ needed. In the context of p\TeX, this process was performed using virtual fonts. On the other hand, Lua\TeX-ja does the adjustment by encapsuling a glyph into a horizontal box. There are two main reasons why we adopted this -method; one is that we feared Lua codes for coexisting with callback by +method; one is that we feared Lua codes for coexisting with callbacks by |luaotfload| package would be large if we use virtual fonts, and the -other is to cope with the shifting of the baseline of characters at the +other is to cope with shifting of the baseline of characters at the same time. \begin{figure} @@ -987,7 +1093,7 @@ may have different height or depth. In that case, it may look better if the real glyph is shifted vertically to match the height-depth ratio specified in the metric. This situation is carefully studied by Otobe~\cite{min10}. Here the policy on this problem is not determined -now, however we want to offer several solutions by \LuaTeX-ja. +now, however we would like to offer several solutions in future development. \section{Conclusion} We have discussed about our \LuaTeX-ja package, which is much affected @@ -996,6 +1102,12 @@ are much refinements which are needed for regular use. The author hopes that this paper and this project contribute the typesetting Japanese, and possibly other Asian languages, under \LuaTeX. +\section*{Acknowledgements} +The author would like to thank Ken Nakano and Hideaki Togashi for their +development of ASCII p\TeX. The author is very grateful to Haruhiko +Okumura for his leadership in the Japanese \TeX\ community. The author +is also very grateful to members of the \LuaTeX-ja project team for their +valuable cooperation in development. %%% The style of the bibiliogrphy is `amsplain'. \providecommand{\bysame}{\leavevmode\hbox to3em{\hrulefill}\thinspace}