%%
%% This is file 'bxcjkvert.sty'.
%% 
%% Copyright (c) 2013-2026 Takayuki YATO (aka. "ZR")
%%   GitHub:   https://github.com/zr-tex8r
%%   Twitter:  @zr_tex8r
%%
%% This package is distributed under the MIT License.
%%

%% package declaration
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{bxcjkvert}[2026/03/31 v0.5a]
\def\bxjt@pkgname{bxcjkvert}

%--------------------------------------- general

%% switches
\newif\ifbxjt@linestretch
\newif\ifbxjt@resetfont@@

%% packages
\RequirePackage{etoolbox}
\RequirePackage{keyval}
\RequirePackage{CJKvert}

\AtEndOfPackage{%
  \undef\bxjt@tmpa}

%--------------------------------------- options

%% \bxjt@set@choice
\@onlypreamble\bxjt@set@choice
\def\bxjt@set@choice#1#2{%
  \ifcsundef{bxjt@#1@@#2}{%
    \PackageError\bxjt@pkgname
     {Invalid #1 value: '#2'}\@ehc
  }{\csuse{bxjt@#1@@#2}}}

%%<*> \bxcjkvertsetup{...}
\newcommand*{\bxcjkvertsetup}[1]{%
  \edef\bxjt@tmpa{\noexpand\setkeys{bxjt}{#1}%
  }\bxjt@tmpa}

%% 'usebaselinestretch'
\def\bxjt@usebaselinestretch@@true{%
  \CJK@useBaselinestretch@true \bxjt@linestretchtrue}
\def\bxjt@usebaselinestretch@@false{%
  \CJK@useBaselinestretch@false \bxjt@linestretchtrue}
\def\bxjt@usebaselinestretch@@retain{%
  \CJK@useBaselinestretch@true \bxjt@linestretchfalse}
\ifCJK@useBaselinestretch@
  \bxjt@usebaselinestretch@@true
\else
  \bxjt@usebaselinestretch@@retain
\fi
\define@key{bxjt}{usebaselinestretch}[true]{%
  \bxjt@set@choice{usebaselinestretch}{#1}}
%% 'resetfont'
%\newif\ifbxjt@resetfont
\define@key{bxjt}{resetfont}[true]{%
  \bxjt@set@choice{resetfont}{#1}}
%% 'main'
\let\bxjt@main\relax
\def\bxjt@main@@true{\def\bxjt@main{\CJKvert}}
\def\bxjt@main@@false{\def\bxjt@main{\CJKhorz}}
\def\bxjt@main@@retain{\let\bxjt@main\relax}
\define@key{bxjt}{main}[true]{%
  \bxjt@set@choice{main}{#1}}
% dispatch
\DeclareOption*{%
  \bxcjkvertsetup{\CurrentOption}}
\ProcessOptions*

%--------------------------------------- patching

%% emerge \CJK@horzBaselinestretch
\ifx\CJK@horzBaselinestretch\@undefined
  \edef\CJK@horzBaselinestretch{\baselinestretch}
\fi

%% redefine \CJKvert/\CJKhorz
\protected\def\CJKvert{%
  \CJK@vertical@true
  \gdef\CJK@direction{v}%
  %
  \unless\ifbxjt@linestretch
  \else\ifCJK@useBaselinestretch@
    \edef\CJK@horzBaselinestretch{\baselinestretch}%
    \dimen@\CJK@horzBaselinestretch\p@
    \dimen@\CJKbaselinestretch\dimen@
    \edef\baselinestretch{\strip@pt\dimen@}%
  \else
    \edef\baselinestretch{\CJKbaselinestretch}%
  \fi\fi
  %
  \ifbxjt@resetfont@@ \normalfont
  \else \selectfont
  \fi}
\protected\def\CJKhorz{%
  \CJK@vertical@false
  \gdef\CJK@direction{h}%
  %
  \unless\ifbxjt@linestretch
  \else\ifCJK@useBaselinestretch@
    \edef\baselinestretch{\CJK@horzBaselinestretch}%
  \else
    \edef\baselinestretch{1}%
  \fi\fi
  %
  \ifbxjt@resetfont@@ \normalfont
  \else \selectfont % apply \baselinestretch
  \fi}



%% begin-document hoooks
\long\def\bxjt@tmpa#1\CJKvert#2\bxjt@tmpa{%
  \edef\@begindocumenthook{\unexpanded{#1#2}}%
}\expandafter\bxjt@tmpa\@begindocumenthook\relax\bxjt@tmpa
  % \relax, so that #2 would not be a sole {...}
\AfterEndPreamble{%
  \bxjt@main}

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