LaTeX: Paragraph formatting like “karakasa-renban”

tckarakasa.sty

% tckarakasa.sty

%% package declaration
\NeedsTeXFormat{pLaTeX2e}
\ProvidesPackage{tckarakasa}[2015/02/05 v0.1]

%% preparations
\def\tckk@pkgname{tckarakasa}
\def\tckk@error{\PackageError\tckk@pkgname}
\providecommand\bxDebug[1]{}

%% prerequisite
\RequirePackage{etoolbox}
\RequirePackage{graphicx}

%--------------------------------------- helpers

%% variables
\newbool{tckk@g@last@line}
\newbox\tckk@g@orgbox
\newbox\tckk@g@procbox
\newbox\tckk@g@linebox
\let\tckk@line@count\relax
\let\tckk@linewidth\relax

%% unique tokens
\def\tckk@end{\tckk@end@}
\def\tckk@mt{\tckk@mt@}

%--------------------------------------- public stuffs

%%<*> \begin{karakasa}{<width>}...\end{karakasa}
\newenvironment{karakasa}[1]{%
  \setlength\@tempdima{#1}%
  \edef\tckk@linewidth{\the\@tempdima}%
  \global\setbox\tckk@g@orgbox\vbox\bgroup\tate
    \tckk@set@box@param
    \bgroup
}{%
  \egroup\egroup
  \tckk@split@lines
  \tckk@draw@text
  \box\tckk@g@procbox
}

%% \tckk@set@box@param
\def\tckk@set@box@param{%
  \hsize\tckk@linewidth\relax
  \@parboxrestore
  \raggedright
  \interlinepenalty\z@
  \clubpenalty\z@
  \widowpenalty\z@
  \displaywidowpenalty\z@
  \brokenpenalty\z@
  \lineskip2\baselineskip
  \baselineskip\z@
  \lineskiplimit\maxdimen
}

%--------------------------------------- splitter

%% constants
\chardef\tckk@max@factor=5

%% variables
\let\tckk@factor\relax
\let\tckk@g@retcode\relax
\newbox\tckk@normbox

%% temporaries
\chardef\tckk@boxa=2
\chardef\tckk@boxb=4
\chardef\tckk@boxc=6

%% \tckk@dir
% \tate or \yoko, or just \relax
\let\tckk@dir\tate

%% \tckk@split@lines
% Splits \tckk@g@orgbox into "line chunks" (hbox), arranges
% them inside a vbox in reverse order, and stores the box
% in \tckk@g@procbox. In addition, the number of line chunks
% is stored to \tckk@line@count.
\def\tckk@split@lines{%
  \def\tckk@line@count{0}%
  \global\setbox\tckk@g@procbox\vbox{\tckk@dir}%
  \tckk@split@lines@a
\bxDebug{karakasa: \tckk@line@count\ifnum\tckk@g@retcode=3 +\fi
\space lines}%
}
\def\tckk@split@lines@a{%
  \def\tckk@factor{0}%
  \tckk@split@once
  \ifnum\tckk@g@retcode<3
    \numdef\tckk@line@count{\tckk@line@count+1}%
  \fi
  \global\setbox\tckk@g@procbox\vbox{\tckk@dir
    \box\tckk@g@linebox
    \unvbox\tckk@g@procbox
  }%
  \ifnum\tckk@g@retcode<2
    \expandafter\tckk@split@lines@a
  \fi
}

%% \tckk@split@once
\def\tckk@split@once{%
  \numdef\tckk@factor{\tckk@factor+1}%
  \ifnum\tckk@factor>\tckk@max@factor
    \global\chardef\tckk@g@retcode=4
    \def\tckk@line@count{0}%
    \global\setbox\tckk@g@procbox\vbox{\tckk@dir}%
  \else \expandafter\tckk@split@once@a
  \fi
}
\def\tckk@split@once@a{%
  \begingroup
    \splitmaxdepth\maxdimen
    \splittopskip\z@
    \vbadness\@M
    \setbox\tckk@boxa\copy\tckk@g@orgbox
    \setbox\tckk@boxb\vsplit\tckk@boxa to\tckk@factor\baselineskip
    \setbox\tckk@boxc\vbox{\tckk@dir
      \unvbox\tckk@boxb
      \tckk@discard@stuffs
      \global\setbox\tckk@g@linebox\lastbox
      \tckk@discard@stuffs
    }%
    {\setbox\tckk@boxb\vbox{\tckk@dir % chenge-dir
      \ht\tckk@boxc\z@ \dp\tckk@boxc\z@
    }}%
    \unless\ifvoid\tckk@g@linebox
      \global\setbox\tckk@g@linebox\hbox{\tckk@dir
        \box\tckk@boxc
        \ht\tckk@g@linebox\z@ \dp\tckk@g@linebox\z@
        \box\tckk@g@linebox
      }%
    \fi
    \ifvoid\tckk@boxa
      \ifvoid\tckk@g@linebox
        \global\chardef\tckk@g@retcode=3
        \global\setbox\tckk@g@linebox\hbox{\tckk@dir
          \box\tckk@boxc
        }%
      \else \global\chardef\tckk@g@retcode=2
      \fi
    \else
      \ifvoid\tckk@g@linebox
        \global\chardef\tckk@g@retcode=0
      \else \global\chardef\tckk@g@retcode=1
      \fi
    \fi
    \ifnum\tckk@g@retcode>0
      \global\setbox\tckk@g@orgbox\box\tckk@boxa
    \fi
  \endgroup
  \ifnum\tckk@g@retcode=0
    \expandafter\tckk@split@once
  \fi
}

%% \tckk@discard@stuffs
\def\tckk@discard@stuffs{%
  \let\tckk@next\tckk@discard@stuffs
  \ifnum     \lastnodetype=11 \unskip
  \else\ifnum\lastnodetype=12 \unkern
  \else\ifnum\lastnodetype=13 \unpenalty
  \else \let\tckk@next\relax
  \fi\fi\fi \tckk@next
}

%--------------------------------------- drawing

%% variables
\let\tckk@iradius\relax
\let\tckk@oradius\relax
\let\tckk@phi\relax
\let\tckk@omega\relax

%% \tckk@draw@text
\def\tckk@draw@text{%
  \leavevmode
  \ifnum\tckk@line@count>0
    \@tempdima\tckk@line@count\baselineskip
    \dimdef\tckk@iradius{0.159155\@tempdima}%
    \dimdef\tckk@oradius{\tckk@iradius+\tckk@linewidth}%
    \dimdef\tckk@phi{360pt/\tckk@line@count}%
    \dimdef\tckk@omega{0pt}%
    \global\setbox\tckk@g@procbox\hbox{%
      \kern\tckk@oradius\relax
      \tckk@draw@text@a
      \kern\tckk@oradius\relax
    }%
    \ht\tckk@g@procbox\tckk@oradius\relax
    \dp\tckk@g@procbox\tckk@oradius\relax
  \else
    \global\setbox\tckk@g@procbox\hbox{%
      \ht\tckk@g@procbox\z@ \dp\tckk@g@procbox\z@
      \wd\tckk@g@procbox\z@ \box\tckk@g@procbox
    }%
  \fi
%\showbox\tckk@g@procbox
}
\def\tckk@draw@text@a{%
  \begingroup
    \@whilenum{\tckk@line@count>\z@}\do{%
      \global\setbox\tckk@g@procbox\vbox{\tate
        \unvbox\tckk@g@procbox \unskip
        \global\setbox\tckk@g@linebox\lastbox
      }%
      \edef\tckk@tmpa{\expandafter\rem@pt\tckk@omega}%
      \setbox\tckk@boxa\hbox{\hb@xt@\z@{\tate
        \kern\tckk@iradius\relax
        \box\tckk@g@linebox
        \hss
      }}%
      \rotatebox{\tckk@tmpa}{\box\tckk@boxa}%
      \dimdef\tckk@omega{\tckk@omega-\tckk@phi}%
      \numdef\tckk@line@count{\tckk@line@count-1}%
    }%
    \global\setbox\tckk@g@procbox\vbox{\tate
      \unvbox\tckk@g@procbox \unskip
      \global\setbox\tckk@g@linebox\lastbox
    }%
    \unless\ifvoid\tckk@g@linebox
      \hbox{\hb@xt@\z@{\tate\box\tckk@g@linebox\hss}}%
    \fi
  \endgroup
}

%--------------------------------------- all done
\endinput
%% EOF

test-tckarakasa.tex

\documentclass[a4paper,dvipdfmx]{jsarticle}
\usepackage{tckarakasa}
\begin{document}
\begin{karakasa}{10zw}
日本国民は、正当に選挙された国会における代表者を通じて行動し、
われらとわれらの子孫のために、諸国民との協和による成果と、
わが国全土にわたつて自由のもたらす恵沢を確保し、
政府の行為によつて再び戦争の惨禍が起ることのないやうにすることを決意し、
ここに主権が国民に存することを宣言し、この憲法を確定する。
そもそも国政は、国民の厳粛な信託によるものであつて、
その権威は国民に由来し、その権力は国民の代表者がこれを行使し、
その福利は国民がこれを享受する。これは人類普遍の原理であり、
この憲法は、かかる原理に基くものである。われらは、
これに反する一切の憲法、法令及び詔勅を排除する。
\end{karakasa}
\end{document}