% This is the file ruby.sty of the CJK package
%   for displaying ruby (i.e. furigana).
%
% created by Werner Lemberg <wl@gnu.org>
%
% Version 4.8.5 (16-Oct-2021)

% Copyright (C) 1994-2021  Werner Lemberg <wl@gnu.org>
%
% This program is free software; you can redistribute it and/or modify
% it under the terms of the GNU General Public License as published by
% the Free Software Foundation; either version 2 of the License, or
% (at your option) any later version.
%
% This program is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
% GNU General Public License for more details.
%
% You should have received a copy of the GNU General Public License
% along with this program in doc/COPYING; if not, write to the Free
% Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
% MA 02110-1301 USA

\NeedsTeXFormat{LaTeX2e}[1995/06/01]
\def\fileversion{4.8.5}
\def\filedate{2021/10/16}
\ProvidesPackage{ruby}[\filedate\space\fileversion]


\RequirePackage{CJK}[1996/11/20]

\newif\ifruby@overlap@
\newif\ifruby@CJK@

\DeclareOption{overlap}{\ruby@overlap@true}
\DeclareOption{nooverlap}{\ruby@overlap@false}
\DeclareOption{CJK}{\ruby@CJK@true}
\DeclareOption{latin}{\ruby@CJK@false}

\ExecuteOptions{overlap, CJK}

\ProcessOptions


% we suppress any unwanted spaces produced by linefeeds.

\endlinechar \m@ne

% to get a small separation between adjacent lines.

\lineskiplimit 1pt


\newdimen\ruby@width
\edef\ruby@kern{\kern -5sp\kern 5sp}

\newcommand{\rubysize}{0.4}
\newcommand{\rubysep}{-0.5ex}
\newcommand{\rubyoverlap}{\ruby@overlap@true}
\newcommand{\rubynooverlap}{\ruby@overlap@false}
\newcommand{\rubyCJK}{\ruby@CJK@true}
\newcommand{\rubylatin}{\ruby@CJK@false}


% #1 is the base character; #2 is the ruby.

\DeclareRobustCommand{\ruby}[2]{
  {\@tempdimc \f@size\p@
   \@tempdimc \rubysize\@tempdimc
   \sbox\z@{\vrule\@height.7\baselineskip\@depth\z@\@width\z@ #1}
   \sbox\@tempboxa{\fontsize{\@tempdimc}{1.2\@tempdimc}\selectfont
                   \vrule\@height\z@\@depth.3\baselineskip\@width\z@ #2}

   % save width value of previous ruby (if applicable)
   \@tempdimb\ruby@width

   \global\ruby@width \wd\@tempboxa
   \global\advance\ruby@width -\wd\z@
   \ifdim\ruby@width > \z@
     \global\divide\ruby@width \tw@
   \else
     \global\ruby@width \z@
   \fi

   % we first compute the box of the ruby with its base character(s).
   \ifruby@overlap@
     \setbox\@tempboxa \vbox{
       \hbox to \wd0{\hss \box\@tempboxa \hss}
       \nointerlineskip
       \kern\rubysep
       \box\z@}
   \else
     \ifdim\ruby@width > \z@
       \@tempdima \wd\@tempboxa
     \else
       \@tempdima \wd\z@
     \fi
     \setbox\@tempboxa \vbox{
       \hbox to \@tempdima{\hss \box\@tempboxa \hss}
       \nointerlineskip
       \kern\rubysep
       \hbox to \@tempdima{\hss \box\z@ \hss}}
   \fi

   % are we at the beginning of a paragraph?
   \ifvmode
     \leavevmode
     \ifruby@overlap@
       \kern\ruby@width
     \fi
   \else

     % has previous character a ruby with \ruby@width > 0?
     \ifnum\lastkern = 5%        \ruby@kern
       \kern\@tempdimb
       \ifruby@CJK@
         \nobreak
         \CJKglue
         \nobreak
       \fi
       \ifruby@overlap@
         \kern\ruby@width
       \fi
     \else

       \ifruby@CJK@

         % is previous character an ordinary CJK character?
         \ifnum\lastkern = \@ne%        \CJK@CJK
           \ifdim\ruby@width > \z@
             \nobreak
             \CJKglue
             \nobreak
           \else
             \CJKglue
           \fi
         \else

           % is previous character a punctuation character?
           \ifnum\lastkern = \tw@%      \CJK@kern
             \nobreak
             \CJKglue
             \nobreak
           \fi
         \fi
       \fi
     \fi
   \fi
  
   \box\@tempboxa

   \ifdim\ruby@width > \z@
     \ruby@kern
     \ifruby@overlap@
     \else
       \global\ruby@width\z@
     \fi
   \else
     \kern -1sp
     \kern 1sp
     \global\ruby@width\z@
   \fi}

  \ifruby@CJK@
    \ignorespaces
  \fi}


% reset endline character.

\endlinechar `\^^M

\endinput
