ltj-jfont.lua: "-ltjksp" disables ksp_{natural,stretch,shrink} key in JFM

[luatex-ja/luatexja.git] / doc / luatexja.dtx

diff --git a/doc/luatexja.dtx b/doc/luatexja.dtx
index 1e2ae1b..0c159e4 100644 (file)
--- a/doc/luatexja.dtx
+++ b/doc/luatexja.dtx
@@ -4420,7 +4420,7 @@ Furthermore, the glyph is shifted according to values of fields
 \end{figure}
 
 \item[kern={\{[$j$]=<kern>, [$j'$]=\{<kern>, [ratio=<ratio>]\}, ...\}}]
-
+\nopagebreak
 \item[glue={\{[$j$]=\{<width>, <stretch>, <shrink>, [ratio=<ratio>, ...]\}, ...\}}]\leavevmode
 %<*ja>
 
@@ -4441,7 +4441,7 @@ $0$から$+1$の実数値をとる．省略時の値は$0.5$である．
 %<*en>
 \
 
-Specifies the width of kern or glue which will be inserted
+Specifies the amount of kern or glue which will be inserted
 between characters in character class~$i$ and those in character class~$j$.
 
 <ratio> specifies how much the glue is originated in the ``right'' character.
@@ -4464,9 +4464,34 @@ we specify <ratio> to $0.25/(0.5+0.25)=1/3$.
              度を$-2$から$+2$の間の整数で指定する．大きい値ほど「伸びやすく，縮みやすい」
              ことを意味する．省略時の値
              は0であり，範囲外の値が指定されたときの動作は未定義である．
-\item[ksp\_natural=<bool>]
-\item[ksp\_stretch=<bool>]
-\item[ksp\_shrink=<bool>]
+\item[ksp\_natural=<num>\textrm{, }%
+  ksp\_stretch=<num>\textrm{, }ksp\_shrink=<num>]\leavevmode
+
+JFMによって本来挿入されるグルーの他に
+\Param{kanjiskip}分の空白を自然長(\texttt{ksp\_natural})，伸び量(\texttt{ksp\_stretch})，
+縮み量(\texttt{ksp\_shrink})ごとに挿入する\footnote{本来\Param{xkanjiskip}が挿入される場所においては
+            \Param{xkanjiskip}分の空白を自然長・伸び量・縮み量ごとに．追加できる．}%
+ための指定である．いずれも省略された場合のデフォルト値は0（追加しない）である．
+
+例えば，\LuaTeX-jaの横組標準JFMの \texttt{jfm-ujis.lua} では，
+\begin{itemize}
+ \item 通常の文字「あ」と開き括弧類の間に入るグルーは，自然長・縮み量半角，伸び量0のグルー
+となっているが，さらに\Param{kanjiskip}の伸び量に \texttt{ksp\_stretch}（ここでは1）を掛け
+       た分だけ伸びることが許される．
+ \item 同様に，閉じ括弧類（全角コンマ「，」も含む）と通常の文字「う」「え」の間にも
+自然長・縮み量半角，伸び量0のグルー
+となっているが，さらに\Param{kanjiskip}の伸び量に \texttt{ksp\_stretch}（ここでは1）を掛け
+       た分だけ伸びることが許される．
+\end{itemize}
+となっている．従って，以下のような組版結果を得る．
+
+\medskip
+\begin{LTXexample}[width=16\zw]
+\leavevmode
+\ltjsetparameter{kanjiskip=0pt plus 3\zw}
+\vrule\hbox to 15\zw{あ「い」う，えお}\vrule
+\end{LTXexample}
+
 \end{cslist}
 %</ja>
 %<*en>
@@ -4478,9 +4503,35 @@ An integer in $[-2,2]$ (treated as 0 if omitted), and this is
 used only in line adjustment with priority by \Pkg{luatexja-adjust}
 (see Subsection~\ref{ssec-adj}). Higher value means the glue is easy to stretch,
 and is also easy to shrink.
-\item[ksp\_natural=<bool>]
-\item[ksp\_stretch=<bool>]
-\item[ksp\_shrink=<bool>]
+\item[ksp\_natural=<num>\textrm{, }%
+  ksp\_stretch=<num>\textrm{, }ksp\_shrink=<num>]\leavevmode
+
+These keys specifies whether the natural width of \Param{kanjiskip}
+(the stretch/shrink part, respectively) will be inserted in addition to the original
+JFM glue. Default values of them are all 0.
+
+As an example, in \texttt{jfm-ujis.lua}, the standard JFM in horizontal writing, we have
+\begin{itemize}
+ \item Between an ordinal letter ``あ'' and an ideographic opening bracket, we have
+a glue whose natural part and shrink part are both half-width, while its stretch part is
+       zero. However, this glue also can be stretched
+       as much as the stretch part of \Param{kanjiskip} times the value of
+       \texttt{ksp\_stretch} key (1 in this case).
+ \item Between an ideographic closeing brackets (the ideographic comma ``，''
+       is included) and an ordinal letter, we have the same glue. 
+       Again, this glue also can be stretched
+       as much as the stretch part of \Param{kanjiskip} times the value of
+       \texttt{ksp\_stretch} key (1 in this case).
+\end{itemize}
+Hence we have the following result:
+
+\medskip
+\begin{LTXexample}[width=16\zw]
+\leavevmode
+\ltjsetparameter{kanjiskip=0pt plus 3\zw}
+\vrule\hbox to 15\zw{あ「い」う，えお}\vrule
+\end{LTXexample}
+
 \end{cslist}
 %</en>