LaTeX：とにかくTikZでcurrent pageしたいときに使うやつ

## bxpgfcurpage.sty
%%
%% This is file 'bxpgfcurpage.sty'.
%%
%% Copyright (c) 2019 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{bxpgfcurpage}[2019/05/18 v0.2]
\def\bxqpp@pkgname{bxpgfcurpage}
\providecommand\bxDebug[1]{}

%--------------------------------------- environment check

%% packages
\RequirePackage{pgf}[]
\RequirePackage{everyshi}[]% loaded by pgf
\RequirePackage{etoolbox}[2011/01/03]% v2.1
\ifx\numdef\@undefined\endinput\fi
\RequirePackage{pdftexcmds}[2011/11/11]% v0.11

%% unique tokens
\def\bxqpp@end{\bxqpp@end@}

%% \bxqpp@driver
%% The pgf driver type.
\let\bxqpp@driver@@dvips=d
\let\bxqpp@driver@@dvipdfmx=d
\let\bxqpp@driver@@dvisvgm=d
\let\bxqpp@driver@@xetex=x
\let\bxqpp@driver@@pdftex=p
\let\bxqpp@driver@@luatex=p
\let\bxqpp@driver\relax
\edef\bxqpp@tmpa{\csuse{pgfsysdriver}}
\def\bxqpp@next#1-#2.#3\bxqpp@end{%
  \PackageInfo\bxqpp@pkgname
   {Pgf driver is '#2'\@gobble}%
  \letcs\bxqpp@driver{bxqpp@driver@@#2}%
  \ifundef\bxqpp@driver{%
    \PackageError\bxqpp@pkgname
     {The pgf driver (#2) is not supported}%
     {Package loading is aborted}%
    \endinput
  }{}}
\expandafter\bxqpp@next\bxqpp@tmpa\bxqpp@end

%% switch 'bxqpp@dviish'
\newbool{bxqpp@dviish}
\ifx d\bxqpp@driver \bxqpp@dviishtrue
\else\ifx x\bxqpp@driver \bxqpp@dviishtrue
\fi\fi

%% \bxqpp@width / \bxqpp@height / \bxqpp@savepos / etc.
%% General primitives.
\pdf@isprimitive\pdfvariable\pdfvariable{%
  \edef\bxqpp@horigin{\pdfvariable horigin}%
  \edef\bxqpp@vorigin{\pdfvariable vorigin}%
}{}
\def\bxqpp@next#1#2{\pdf@isprimitive#2#2{\let#1#2}{}}
\bxqpp@next\bxqpp@pagewidth\pdfpagewidth
\bxqpp@next\bxqpp@pagewidth\pagewidth
\bxqpp@next\bxqpp@pageheight\pdfpageheight
\bxqpp@next\bxqpp@pageheight\pageheight
\bxqpp@next\bxqpp@horigin\pdfhorigin
\bxqpp@next\bxqpp@vorigin\pdfvorigin
\bxqpp@next\bxqpp@savepos\pdfsavepos
\bxqpp@next\bxqpp@savepos\savepos
\bxqpp@next\bxqpp@lastxpos\pdflastxpos
\bxqpp@next\bxqpp@lastxpos\lastxpos
\bxqpp@next\bxqpp@lastypos\pdflastypos
\bxqpp@next\bxqpp@lastypos\lastypos
\bxqpp@next\bxqpp@readpapersizespecial\readpapersizespecial
\@tempswafalse
\unless\ifnum \ifdef\bxqpp@savepos10%
    \ifdef\bxqpp@pageheight10\ifdef\bxqpp@pagewidth10%
    \ifdef\bxqpp@lastxpos10\ifdef\bxqpp@lastypos10=11111
  \PackageError\bxqpp@pkgname
   {The engine in use is not supported}%
   {Package loading is aborted}%
\expandafter\endinput\fi\relax

%% switch 'bxqpp@eptex'
\newbool{bxqpp@eptex}
\pdf@isprimitive\kanjiskip\kanjiskip{\bxqpp@eptextrue}{}

%% Always enable tracking when e-pTeX is used.
% (Old versions of pgf fail to do it.)
\ifbxqpp@eptex\ifx d\bxqpp@driver
  \ifdef\pgfsyspdfmark{}{%else
    \ifdef\pgf@sys@pdf@dvi@tracker{%
      \pgf@sys@pdf@dvi@tracker
      \PackageInfo\bxqpp@pkgname
       {Position marking enabled\@gobble}%
    }{}}
\fi\fi

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

%% variables
\newbool{bxqpp@ok}
\newbool{bxqpp@has@stocksize}

%% \bxqpp@endpreamble@hook
% It is executed before begin-document hooks.
\@onlypreamble\bxqpp@endpreamble@hook
\let\bxqpp@endpreamble@hook\@empty
\AtEndPreamble{\bxqpp@endpreamble@hook}

%% \bxqpp@begindoc@hook
% The begin-document hook.
\@onlypreamble\bxqpp@begindoc@hook
\let\bxqpp@begindoc@hook\@empty
\AtBeginDocument{\bxqpp@begindoc@hook}

%--------------------------------------- papersize special

% This package assumes that \bxqpp@pagewidth (\pdfpagewidth)
% and \bxqpp@pageheight always have the correct information.

%% \bxqpp@mag@value
% The value of \mag/1000 as decimal. (expandable)
\def\bxqpp@mag@value{%
  \ifnum\mag<32768 \ifnum\mag>\z@
    \expandafter\bxqpp@mag@value@a\the\numexpr\mag+100000;%
  \fi\fi}
\def\bxqpp@mag@value@a#1#2#3#4;{#2#3.#4}

%% \bxqpp@papersize@special
% Issues a "correct" papersize special; that is, lengths are
% really in true-dimen.
\def\bxqpp@papersize@special{%
  \ifnum\mag=\@m
    \bxqpp@papersize@special@dumb
  \else
    \def\bxqpp@tmpx{\bxqpp@mag@value}%
    \special{papersize=%
        \the\dimexpr\bxqpp@mag@value\bxqpp@pagewidth\relax,%
        \the\dimexpr\bxqpp@mag@value\bxqpp@pageheight\relax}%
  \fi}

%% \bxqpp@papersize@special@dumb
% Issues an "incorrect" papersize special, where lengths are
% NOT in true-dimen; unfortunately, the buggy "read-papersize"
% mechanism of the old e-pTeX requires this "incorrect" form.
\def\bxqpp@papersize@special@dumb{%
  \special{papersize=\the\bxqpp@pagewidth,\the\bxqpp@pageheight}}

%% every-shipout hook
% We put papersize specials at both the head and the bottom of
% the output box to "win the race".
\ifx d\bxqpp@driver
  \EveryShipout{%
    \setbox\@cclv\vbox{%
      \bxqpp@papersize@special
      \box\@cclv
      \bxqpp@papersize@special}}
\fi

%--------------------------------------- countermeasure to geoemtry

% The geometry package alters the values of \paperwidth and
% \paperheight in its begin-document hook. This behavior
% breaks the function of this package and thus we need some
% fix for it.

%% \bxqpp@paperwidth/\bxqpp@paperheight
% There names are used instead of \paperwidth/height.
% Initially, \bxqpp@paperXXX is an alias to \paperXXX.
\let\bxqpp@paperwidth\paperwidth
\let\bxqpp@paperheight\paperheight
% Use the "end-preamble" hook, to surely go ahead of the
% geometry's begin-document hook.
\appto\bxqpp@endpreamble@hook{%
  \unless\ifnum\mag=\@m
    \@ifpackageloaded{geometry}{%
      % Then geometry will alter the values later, so we
      % freeze the values by declaring new variables.
      \newdimen\bxqpp@paperwidth \bxqpp@paperwidth\paperwidth
      \newdimen\bxqpp@paperheight \bxqpp@paperheight\paperheight
      % Some pgf stuffs must be patched to use \bxqpp@paperXXX
      % instead of \paperXXX.
      \patchcmd\pgfsys@thepagewidth{%
        \paperwidth}{\bxqpp@paperwidth}{}{}%
      \patchcmd\pgfsys@thepageheight{%
        \paperheight}{\bxqpp@paperheight}{}{}%
    }{}%
  \fi}

%--------------------------------------- suppress "read papersize special"

% We do not want \bxqpp@pagewidth/\bxqpp@pageheight to be altered
% to wrong values through e-pTeX's "read papersize special"
% meachanism. So this feature must be (somehow) disabled, at
% least when wrong papersize specials could appear.

%% variables
\let\bxqpp@suppress\@empty % (for debug)

%%<+> \SuppressReadPapersizeSpecial
% Disables unconditionally e-pTeX's "read papersize special"
% feature. It will be invoked by the author.
\newrobustcmd*\SuppressReadPapersizeSpecial{%
  \gdef\bxqpp@needs@suppress@read@papersize{%
    \bxqpp@oktrue}}

%% \bxqpp@init@suppress@read@papersize
\@onlypreamble\bxqpp@init@suppress@read@papersize
\def\bxqpp@init@suppress@read@papersize{%
  \ifdefined\bxqpp@readpapersizespecial
    \def\bxqpp@suppress{P}%
    \appto\bxqpp@begindoc@hook{%
      \bxqpp@needs@suppress@read@papersize\ifbxqpp@ok
        \def\bxqpp@suppress{P+}%
        \global\bxqpp@readpapersizespecial\z@
      \fi}%
  \else\ifbxqpp@eptex
    % Hook into \pdfsavepos, to annihilate the effect
    % of the read-papersize.
    % NB. This hook should be activated whenever \pdfsavepos
    % is invoked, thus is activated right now, not inside the
    % begin-document hook.
    \def\bxqpp@suppress{H}%
    \let\bxqpp@org@savepos\pdfsavepos
    \let\pdfsavepos\bxqpp@patched@savepos
    \let\bxqpp@savepos\pdfsavepos
    \appto\bxqpp@begindoc@hook{%
      \bxqpp@needs@suppress@read@papersize\ifbxqpp@ok
        \newdimen\bxqpp@pagewidth \bxqpp@pagewidth\pdfpagewidth
        \newdimen\bxqpp@pageheight \bxqpp@pageheight\pdfpageheight
      \else
        \def\bxqpp@suppress{H-}%
        \global\let\pdfsavepos\bxqpp@org@savepos
        \global\let\bxqpp@savepos\pdfsavepos
      \fi}%
  \fi\fi}
\AtEndOfPackage{% deferred
  \bxqpp@init@suppress@read@papersize}

%% \bxqpp@patched@savepos
% NB. It assumes the buggy behavior of old e-pTeX.
\@onlypreamble\bxqpp@patched@savepos
\protected\def\bxqpp@patched@savepos{%
  \bxqpp@papersize@special@dumb
  \bxqpp@org@savepos
  \unless\ifnum\mag=\@m
    \bxqpp@papersize@special
  \fi}

%% \bxqpp@needs@suppress@read@papersize
\def\bxqpp@needs@suppress@read@papersize{%
  \ifbxqpp@has@stocksize \bxqpp@oktrue
  \else\unless\ifnum\mag=\@m \bxqpp@oktrue
  \else\bxqpp@okfalse
  \fi\fi}

%--------------------------------------- user-side TeX offsets

%% variables
\newbool{bxqpp@user@side@offsets}

%%<+> \UserSideTeXOffsets
\@onlypreamble\UserSideTeXOffsets
\newrobustcmd*\UserSideTeXOffsets{%
  \bxqpp@user@side@offsetstrue}
%%<+> \SystemSideTeXOffsets
\@onlypreamble\SystemSideTeXOffsets
\newrobustcmd*\SystemSideTeXOffsets{%
  \bxqpp@user@side@offsetsfalse}

%--------------------------------------- set proper papersize

%% variables
\newdimen\OriginOffsetH
\newdimen\OriginOffsetV

% Tentative setting.
\bxqpp@pagewidth\paperwidth
\bxqpp@pageheight\paperheight
\OriginOffsetH\hoffset
\OriginOffsetV-\voffset

%% redefine \pgf@sys@pdf@mark@pos@pgfpageorigin
\def\pgf@sys@pdf@mark@pos@pgfpageorigin{%
  \pgfqpoint{\OriginOffsetH}{\OriginOffsetV}}

%% switch 'bxqpp@tombow'
\newbool{bxqpp@tombow}
\expandafter\ifx\csname iftombow\expandafter\endcsname
    \csname iftrue\endcsname
  \bxqpp@tombowtrue
\fi

%% \bxqpp@toc
% The coefficient for TeX offsets.
\def\bxqpp@toc{%
  \ifbxqpp@user@side@offsets
    \ifx x\bxqpp@driver 2\else 1\fi
  \else
    \ifx x\bxqpp@driver 1\else 0\fi
  \fi}

%% \bxqpp@mft
% The mag-fix term.
\def\bxqpp@mft#1{%
  \ifbxqpp@dviish \unless\ifnum\mag=\@m #1\fi\fi}

%% begin-document hook
\appto\bxqpp@begindoc@hook{%
  \bxqpp@pagewidth\bxqpp@paperwidth
  \bxqpp@pageheight\bxqpp@paperheight
  \bxqpp@has@stocksizefalse
  % 'tombow' is on but \stockXXX is absent
  \ifbxqpp@tombow
    \bxqpp@pagewidth\dimexpr\bxqpp@paperwidth+2truein\relax
    \bxqpp@pageheight\dimexpr\bxqpp@paperheight+2truein\relax
    \bxqpp@has@stocksizetrue
  \fi
  % \stockXXX is present
  \ifdim\ifundef\stockwidth{\z@}{\stockwidth}>\z@
  \ifdim\ifundef\stockheight{\z@}{\stockheight}>\z@
    \bxqpp@pagewidth\stockwidth
    \bxqpp@pageheight\stockheight
    \bxqpp@has@stocksizetrue
  \fi\fi
  \OriginOffsetH\dimexpr
    (\bxqpp@pagewidth-\bxqpp@paperwidth)/2+\bxqpp@toc\hoffset
    \bxqpp@mft{+1in-1truein}\relax
  \OriginOffsetV\dimexpr
    (\bxqpp@pageheight-\bxqpp@paperheight)/2-\bxqpp@toc\voffset
    \bxqpp@mft{-1in+1truein}\relax}

%--------------------------------------- debug information

\@onlypreamble\bxqpp@driver@name
\edef\bxqpp@driver@name{%
  \ifx d\bxqpp@driver dvi%
  \else\ifx x\bxqpp@driver xetex%
  \else\ifx p\bxqpp@driver pdftex%
  \else\ifx l\bxqpp@driver luatex%
  \fi\fi\fi\fi}
\AtEndOfPackage{\appto\bxqpp@begindoc@hook{%
  \bxDebug{\bxqpp@pkgname\space info^^J%
  >---------------------------------------<^^J%
  driver = \bxqpp@driver@name^^J%
  mag = \the\mag^^J%
  papersize = \the\paperwidth*\the\paperheight^^J%
  F-papersize = \the\bxqpp@paperwidth*\the\bxqpp@paperheight^^J%
  pagesize = \the\bxqpp@pagewidth*\the\bxqpp@pageheight^^J%
  origin-offset = \the\OriginOffsetH*\the\OriginOffsetV^^J%
  TeX-offset = \the\hoffset*\the\voffset^^J%
  suppress-RPS = \bxqpp@suppress^^J%
  TO-coefficient = \the\numexpr\bxqpp@toc\relax^^J%
  mag-fix-term = \the\dimexpr\z@\bxqpp@mft{+1in-1truein}\relax^^J%
  >---------------------------------------<}%
}}

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

## test-bxpgfcurpage.tex
% pLaTeX/upLaTeX document
\documentclass[autodetect-engine,dvipdfmx,a5paper,17pt,tombow]{jsarticle}
\usepackage{tikz,bxpgfcurpage}
\newcommand\TEST{%
\begin{tikzpicture}[remember picture, overlay]
\coordinate (NE) at (current page.north east);
\coordinate (NW) at (current page.north west);
\coordinate (SE) at (current page.south east);
\coordinate (SW) at (current page.south west);
\coordinate (C) at (current page.center);
\draw[blue,line width=8pt] (SW) rectangle (NE);
\draw[red,line width=4pt]
  (NE) circle (1)
  (NW) circle (1)
  (SE) circle (1)
  (SW) circle (1)
  (C)  circle (1);
\draw
  (current page.south) -- (current page.north)
  (current page.west) -- (current page.east);
\end{tikzpicture}}
\begin{document}
TEST \TEST PAGE!
\newpage
TEST\par\vfill\TEST\par\vfill PAGE!
\end{document}