% \iffalse meta-comment -- by the way, this file contains UTF-8
%
% Copyright (C) 2008-2026 by Hans Hagen, Taco Hoekwater, Elie Roux,
% Manuel Pégourié-Gonnard, Philipp Gesang and Kim Dohyun.
% Currently maintained by Kim Dohyun.
% Support: <https://github.com/lualatex/luamplib>
%
% This work is under the GPL v2.0 license.
%
% This work consists of the main source file luamplib.dtx
% and the derived files
%    luamplib.sty, luamplib.lua and luamplib.pdf.
%
% Unpacking:
%    tex luamplib.dtx
%
% Documentation:
%    lualatex luamplib.dtx
%
%<*ignore>
\begingroup
  \def\x{LaTeX2e}%
\expandafter\endgroup
\ifcase 0\ifx\install y1\fi\expandafter
         \ifx\csname processbatchFile\endcsname\relax\else1\fi
         \ifx\fmtname\x\else 1\fi\relax
\else\csname fi\endcsname
%</ignore>
%<*install>
\input docstrip.tex
\Msg{************************************************************************}
\Msg{* Installation}
\Msg{* Package: luamplib - metapost package for LuaTeX.}
\Msg{************************************************************************}

\keepsilent
\askforoverwritefalse

\let\MetaPrefix\relax

\preamble

See source file '\inFileName' for licencing and contact information.

\endpreamble

\let\MetaPrefix\DoubleperCent

\generate{%
  \usedir{tex/luatex/luamplib}%
  \file{luamplib.sty}{\from{luamplib.dtx}{package}}%
}

\def\MetaPrefix{-- }

\def\luapostamble{%
  \MetaPrefix^^J%
  \MetaPrefix\space End of File `\outFileName'.%
}

\def\currentpostamble{\luapostamble}%

\generate{%
  \usedir{tex/luatex/luamplib}%
  \file{luamplib.lua}{\from{luamplib.dtx}{lua}}%
}

\obeyspaces
\Msg{************************************************************************}
\Msg{*}
\Msg{* To finish the installation you have to move the following}
\Msg{* files into a directory searched by TeX:}
\Msg{*}
\Msg{*     luamplib.sty luamplib.lua}
\Msg{*}
\Msg{* Happy TeXing!}
\Msg{*}
\Msg{************************************************************************}

\endbatchfile
%</install>
%<*ignore>
\fi
%</ignore>
%<*driver>
\NeedsTeXFormat{LaTeX2e}
\ProvidesFile{luamplib.drv}%
  [2026/05/26 v2.41.3 Interface for using the mplib library]%
\documentclass[11pt,a4paper]{ltxdoc}
\usepackage{geometry,graphicx,xspace}
\usepackage[x11names]{xcolor}
\AssignSocketPlug{build/column/outputbox}{space-floats-footnotes}
%
\def\primarycolor{DodgerBlue4}  %%-> rgb  16  78 139 | #104e8b
\def\secondarycolor{Goldenrod4} %%-> rgb 139 105 200 | #8b6914
%
\usepackage[
   hyperindex=false,
    bookmarks=true,
   colorlinks=true,
    linkcolor=\primarycolor,
     urlcolor=\secondarycolor,
    citecolor=\primarycolor,
     pdftitle={The luamplib package},
   pdfsubject={Interface for using the mplib library},
    pdfauthor={Hans Hagen, Taco Hoekwater, Elie Roux, Philipp Gesang \& Kim Dohyun},
  pdfkeywords={luatex, lualatex, mplib, metapost}
]{hyperref}
\usepackage{fontspec}
\setmainfont[
  Numbers     = OldStyle,
  Ligatures   = TeX,
  BoldFont    = {Linux Libertine O Bold},
  ItalicFont  = {Linux Libertine O Italic},
  SlantedFont = {Linux Libertine O Italic},
]{Linux Libertine O}
\setmonofont[Scale=MatchLowercase]{InconsolataN}
%setsansfont[Ligatures=TeX]{Linux Biolinum O}
\setsansfont[UprightFont=*Medium,BoldFont=*Heavy,Ligatures=TeX,Scale=MatchLowercase]{Iwona}
%setmathfont{XITS Math}

\newcommand\ConTeXt {Con\-\kern-.0667em\TeX t\xspace}

\newcommand*\email [1] {<\href{mailto:#1}{#1}>}
\newcommand \file       {\nolinkurl}

\newcommand*\metapost {\textsc{metapost}\xspace}
\newcommand*\mplib {\pkg{mplib}\xspace}

\protected\def\secref#1{\S\,\ref{sec:#1}}
\newcommand*\notabene{\par\textsc{n.b.}\quad}

\usepackage{luamplib}\mplibforcehmode
\newcount\vln
\def\startmpfig{\setbox0\vbox\bgroup\raggedleft
  \leftskip=0pt plus1fill\relax \parfillskip=0pt plus1fil\relax }
\def\stopmpfig#1{\egroup \vln=0\relax
  \AddToHook{para/begin}[mpfig/example]{\advance\vln 1\relax
    \ifnum #1=\vln \vadjust{\vbox to 0pt{\vskip-2ex \vss \unvbox0 \vss}}\fi }\relax
  \AddToHookNext{env/verbatim/after}{\RemoveFromHook{para/begin}[mpfig/example]}}

\def\bsx{\leavevmode\begingroup\begingroup\color{Goldenrod4}}
\def\esx{\endgroup\endgroup}

\let\descriptionlabelorig\descriptionlabel
\def\descriptionlabel#1{\descriptionlabelorig{\textsf{#1}}}

\flushbottom
\begin{document}
  \DocInput{luamplib.dtx}%
\end{document}
%</driver>
% \fi
%
% \CheckSum{0}
%
% \CharacterTable
%  {Upper-case    \A\B\C\D\E\F\G\H\I\J\K\L\M\N\O\P\Q\R\S\T\U\V\W\X\Y\Z
%   Lower-case    \a\b\c\d\e\f\g\h\i\j\k\l\m\n\o\p\q\r\s\t\u\v\w\x\y\z
%   Digits        \0\1\2\3\4\5\6\7\8\9
%   Exclamation   \!     Double quote  \"     Hash (number) \#
%   Dollar        \$     Percent       \%     Ampersand     \&
%   Acute accent  \'     Left paren    \(     Right paren   \)
%   Asterisk      \*     Plus          \+     Comma         \,
%   Minus         \-     Point         \.     Solidus       \/
%   Colon         \:     Semicolon     \;     Less than     \<
%   Equals        \=     Greater than  \>     Question mark \?
%   Commercial at \@     Left bracket  \[     Backslash     \\
%   Right bracket \]     Circumflex    \^     Underscore    \_
%   Grave accent  \`     Left brace    \{     Vertical bar  \|
%   Right brace   \}     Tilde         \~}
%
% \title{The \pkg{luamplib} package}
% \author{Hans Hagen, Taco Hoekwater, Elie Roux, Philipp Gesang and Kim Dohyun\\
% Current Maintainer: Kim Dohyun\\
% Support: \url{https://github.com/lualatex/luamplib}}
% \date{2026/05/26 v2.41.3}
%
% \maketitle
%
% \begin{abstract}
% \centering
% Package to have \metapost code typeset directly in a document with \LuaTeX
% \end{abstract}
%
% \tableofcontents
%
% \section{Documentation}
%
% This package aims at providing a simple way to typeset directly \metapost
% code in a document with \LuaTeX. \LuaTeX\ is built with the Lua
% \mplib library, that runs \metapost code. This package is basically a
% wrapper for the Lua \mplib functions and some \TeX\
% functions to have the output of the \mplib functions in the PDF.
%
% Using this package is easy: in Plain, type your \metapost code between the
% macros \cs{mplibcode} and \cs{endmplibcode}, and in \LaTeX\ in the
% |mplibcode| environment.
%
% The resulting \metapost figures are put in a \TeX\ |hbox| with dimensions
% adjusted to the \metapost code.
%
% The code of \pkg{luamplib} is basically from the |luatex-mplib.lua| and |luatex-mplib.tex| files
% from \ConTeXt. They have been adapted to \LaTeX\ and Plain by Elie Roux and
% Philipp Gesang and new functionalities have been added by Kim Dohyun.
% The most notable changes are:
%
% \begin{itemize}
% \item Possibility to use |btex| |...| |etex| to typeset \TeX\ code.
%   \bsx|textext| \meta{string}\esx\ is a more versatile macro equivalent to \bsx|TEX| \meta{string}\esx\ from \pkg{TEX.mp}.
%   |TEX| is also allowed and is a synonym of |textext|.
%   The argument of
%   \mplib's primitive |maketext| will also be processed by the same routine.
%
% \item Possibility to use |verbatimtex| |...| |etex| to run a \TeX\ code.
%   \bsx|VerbatimTeX| \meta{string}\esx\ is a more versatile macro corresponding to |verbatimtex| command.
%   Of course the behavior cannot be the same as the stand-alone \pkg{mpost}, so that
%   you cannot include \cs{documentclass}, \cs{usepackage} etc.
%   When these \TeX\ commands are found in |verbatimtex| |...| |etex|, the entire code will be
%   ignored.
%
%   The treatment of |verbatimtex| command has changed a lot since v2.20:
%   see below \secref{mpliblegacybehavior}.
%
% \item In the past,
%   the package required PDF mode in order to have some output.
%   Starting with v2.7 it works in DVI mode as well, though
%   DVIPDFMx is the only DVI tool currently supported.
% \end{itemize}
%
% It seems to be convenient to divide the explanations of some more changes and cautions
% into three parts: \TeX, \textsc{MetaPost}, and Lua interfaces.
%
% \subsection{\TeX}
%
% \subsubsection{\cs{mplibforcehmode}}\label{sec:mplibforcehmode}
%   When this macro is declared, every \metapost figure box will be
%   typeset in horizontal mode, so that \cs{centering}, \cs{raggedleft} etc.\
%   will have effects. \cs{mplibnoforcehmode}, being default for backward compatibility,
%   reverts this setting.\footnote{Actually these commands redefine \cs{prependtomplibbox}. So you
%     can redefine this macro with anything suitable before a box.
%     But see \secref{taggedPDF} on Tagged PDF. }
%
% \subsubsection[\cs{everymplib}, \cs{everyendmplib}]{\cs{everymplib\{...\}}, \cs{everyendmplib\{...\}}}
%   \label{sec:everymplib}
%   \cs{everymplib} and \cs{everyendmplib} redefine
%   the Lua table entry containing \metapost code
%   which will
%   be automatically inserted at the beginning and ending of each \metapost code chunk.
%\startmpfig
%\mpfig draw fullcircle scaled 1cm; \endmpfig
%\stopmpfig{3}
%\begin{verbatim}
%    \everymplib{ beginfig(0); }
%    \everyendmplib{ endfig; }
%    \begin{mplibcode}
%      % beginfig/endfig not needed
%      draw fullcircle scaled 1cm;
%    \end{mplibcode}
%\end{verbatim}
%
% \subsubsection[\cs{mplibsetformat}]{\cs{mplibsetformat\{plain\textbar metafun\}}}
%   \label{sec:mplibsetformat}
%   There are (basically) two formats for \metapost: \emph{plain} and
%   \emph{metafun}. By default, the \emph{plain} format is used, but you can set
%   the format to be used by future figures at any time using
%   \bsx\cs{mplibsetformat}\allowbreak\marg{format name}\esx.
%
%   \notabene As \emph{metafun} is such a complicated format,
%   we cannot support all the special effects provided by \emph{metafun}.
%   At least, however, transparency (actually opacity), shading (gradient colors) and transparency group
%   are fully supported,
%   and outlinetext is supported by our own alternative |mpliboutlinetext|
%   (see below \secref{mpliboutlinetext}).
%   You can try other effects as well, though we did not fully tested their proper functioning.
%
% \begin{description}
% \item[transparency]
%   (|texdoc metafun| \S\,8.2) Transparency is so simple that you can apply it to an object,
%   with \emph{plain} format as well as \emph{metafun},
%   just by appending \bsx|withprescript| |"tr_transparency=|\allowbreak\meta{numeric}|"|\esx\ to the sentence.
%   ($0 \le \meta{numeric} \le 1$)
%
%   From v2.36, |withtransparency| is available with \emph{plain} format as well.
%   See below \secref{luamplibtransparency}.
%
% \item[shading]
%   (|texdoc metafun| \S\,8.3) One thing worth mentioning about shading is:
%   when a color expression is given in string type,
%   it is regarded by \pkg{luamplib} as
%   a color expression of \TeX\ side.
%   For instance, when |withshadecolors("orange",| |2/3red)| is given, the first color |"orange"| will be
%   interpreted as a \pkg{color}, \pkg{xcolor} or \pkg{l3color}'s expression.
%
%   From v2.36, shading is available with \emph{plain} format as well with extended functionality.
%   See below \secref{luamplibshading}.
%
% \item[transparency group]
%   \hypertarget{metafunformat}{}\relax
%   (|texdoc metafun| \S\,8.8)
%   As for transparency group, the current \emph{metafun} document is not correct.
%   The true syntax is:
%\begin{verbatim}
%    draw <picture>|<path> asgroup <string>
%\end{verbatim}
%   where \meta{string} should be |""| (empty), |"isolated"|, |"knockout"|, or |"isolated,knockout"|.
%   Beware that currently many of the PDF rendering applications,
%   except Adobe Acrobat, Foxit Editor and \TeX works,
%   cannot properly render the isolated or knockout effect.
%
%   Transparency group is available with \emph{plain} format as well with extended functionality.
%   See below \secref{transparencygroup}.
% \end{description}
%
% \subsubsection[\cs{mplibnumbersystem}]{\cs{mplibnumbersystem\{scaled\textbar double\textbar decimal\}}}
%   \label{sec:mplibnumbersystem}
%   Users can choose |numbersystem| option.
%   The default value is |scaled|, which can be changed
%   by declaring \bsx\cs{mplibnumbersystem\{double\}}\esx\ or
%   \bsx\cs{mplibnumbersystem\{decimal\}}\esx.
%
% \subsubsection[\cs{mplibshowlog}]{\cs{mplibshowlog\{enable\textbar disable\}}}
%   \label{sec:mplibshowlog}
%   Default: |disable|.
%   When \bsx\cs{mplibshowlog\{enable\}}\esx\footnote{As for user's setting,
%   |enable|, |true| and |yes| are identical;
%   all others are identical to |disable|.} is declared, log messages returned by
%   the \metapost process will be printed to the |.log| file.
%   This is the \TeX{} side interface for |luamplib.showlog|.
%
% \subsubsection[\cs{mpliblegacybehavior}]{\cs{mpliblegacybehavior\{enable\textbar disable\}}}
%   \label{sec:mpliblegacybehavior}
%   \paragraph{Legacy behavior}
%   By default, \cs{mpliblegacybehavior\{enable\}}
%   is already declared for backward compatibility,
%   in which case \TeX\ code in
%   |verbatimtex| |...| |etex| that comes just before |beginfig()|
%   will be inserted before the
%   following \metapost figure box.  In this way,
%   each figure box can be freely moved horizontally or vertically.
%   Also, a box number can be assigned to a figure box, allowing it to be
%   reused later.\footnote{But
%     the recommended way to reuse a figure is using \cs{mplibgroup} command.
%     See below \secref{mplibgroupendmplibgroup}.
%   }
%\begin{verbatim}
%    \mplibcode
%      verbatimtex \moveright 3cm etex; beginfig(0); ... endfig;
%      verbatimtex \leavevmode etex; beginfig(1); ... endfig;
%      verbatimtex \leavevmode\lower 1ex etex; beginfig(2); ... endfig;
%      verbatimtex \endgraf\moveright 1cm etex; beginfig(3); ... endfig;
%    \endmplibcode
%\end{verbatim}
%   \notabene \cs{endgraf} should be used instead of \cs{par} inside
%   mplibcode environment.
%
%   On the other hand, \TeX\ code in |verbatimtex| |...| |etex|
%   between |beginfig()| and |endfig| will be inserted
%   after flushing out the \metapost figure. An example:\footnote{\relax
%     But the recommended way to access \metapost variables
%     from \TeX\ (or Lua) side is to use Lua code via |luamplib.instances|.
%     For details see below \secref{luamplibinstances}.}
%\startmpfig
%\mpfig D:=sqrt(2)**9; draw fullcircle scaled D; VerbatimTeX("\gdef\Dia{"&decimal D&"}");\endmpfig
%\par diameter: \Dia bp.
%\stopmpfig{4}
%\begin{verbatim}
%    \mplibcode
%      D := sqrt(2)**9;
%      beginfig(0);
%        draw fullcircle scaled D;
%        VerbatimTeX("\gdef\Dia{" & decimal D & "}");
%      endfig;
%    \endmplibcode
%    diameter: \Dia bp.
%\end{verbatim}
%
%   \paragraph{New and recommended way}
%   By contrast,
%   when \bsx\cs{mpliblegacybehavior\{disable\}}\esx\ is declared, any
%   |verbatimtex| |...| |etex|, along with |btex| |...| |etex|, will be run
%   sequentially one by one.
%   So, some \TeX\ code in |verbatimtex| |...| |etex| will have effect on
%   |btex| |...| |etex| codes thereafter.
%\startmpfig
%\mpfig draw btex ABC etex; verbatimtex \bfseries etex; draw btex DEF etex shifted (1cm,0); draw btex GHI etex shifted (2cm,0); \endmpfig
%\stopmpfig{4}
%\begin{verbatim}
%    \begin{mplibcode}
%      beginfig(0);
%        draw btex ABC etex;
%        verbatimtex \bfseries etex;
%        draw btex DEF etex shifted (1cm,0);    % bold face
%        draw btex GHI etex shifted (2cm,0);    % bold face
%      endfig;
%    \end{mplibcode}
%\end{verbatim}
%
% \subsubsection[\cs{mplibtextextlabel}]{\cs{mplibtextextlabel\{enable\textbar disable\}}}
%   \label{sec:mplibtextextlabel}
%   Default: |disable|.
%   \bsx\cs{mplibtextextlabel\{enable\}}\esx\ enables
%   the labels typeset via |textext| instead of |infont| operator.
%   So, |label("my text",| |origin)| thereafter is exactly the same as
%   |label(textext| |"my text",| |origin)|.
%
%   \notabene In the background,
%   \pkg{luamplib} redefines |infont| operator so that the right side
%   argument (the font part) is totally ignored. Therefore the left side arguemnt (the text part)
%   will be typeset with the current \TeX\ font.
%
%   From v2.35, however, the redefinition of |infont| operator has been revised:
%   when the character code of the text argument is less than $32$~(control characters),
%   or is equal to $35$~(|#|), $36$~(|$|), \iffalse |$|\fi
%   $37$~(|%|), $38$~(|&|), $92$~(|\|), $94$~(|^|),
%   $95$~(|_|), $123$~(|{|), $125$~(|}|), $126$~(|~|) or $127$~(DEL),
%   the original |infont| operator will be used instead of |textext| operator
%   so that the font part will be honored.
%   Despite the revision, please take care of |char| operator in the text argument,
%   as this might bring unpermitted characters into \TeX.
%
% \subsubsection[\cs{mplibcodeinherit}]{\cs{mplibcodeinherit\{enable\textbar disable\}}}
%   \label{sec:mplibcodeinherit}
%   Default: |disable|.
%   \bsx\cs{mplibcodeinherit\{enable\}}\esx\ enables the inheritance
%   of variables, constants, and macros defined by previous \metapost code chunks.
%   On the other hand, \cs{mplibcodeinherit}\allowbreak|{disable}| will make
%   each code chunk being treated as an independent instance, never
%   affected by previous code chunks.
%
% \subsubsection[\cs{mplibglobaltextext}]{\cs{mplibglobaltextext\{enable\textbar disable\}}}
%   \label{sec:mplibglobaltextext}
%   Default: |disable|.
%   Formerly, to inherit |btex| |...| |etex| boxes as well as other \metapost macros, variables and constants,
%   it was necessary to declare \cs{mplibglobaltextext}\allowbreak|{enable}| in advance.
%   But from v2.27, this is implicitly enabled when \cs{mplibcodeinherit}
%   is enabled.
%   The command still remains mostly for backward compatibility.
%\startmpfig
%\mpfig label(btex $\sqrt{2}$ etex, origin); draw fullcircle scaled 20; picture pic; pic := currentpicture; \endmpfig
%\par\mpfig currentpicture := pic scaled 2; \endmpfig
%\stopmpfig{6}
%\begin{verbatim}
%    \mplibcodeinherit{enable}
%    %\mplibglobaltextext{enable}
%    \everymplib{ beginfig(0);} \everyendmplib{ endfig;}
%    \mplibcode
%      label(btex $\sqrt{2}$ etex, origin);
%      draw fullcircle scaled 20;
%      picture pic; pic := currentpicture;
%    \endmplibcode
%    \mplibcode
%      currentpicture := pic scaled 2;
%    \endmplibcode
%\end{verbatim}
%
% \subsubsection{Separate \metapost instances}
%   \pkg{luamplib} v2.22 has added the support for several named \metapost instances
%   in \LaTeX\ environment |mplibcode| or
%   Plain \TeX\ commands \cs{mplibcode} |...| \cs{endmplibcode}.
%   The syntax for \LaTeX\ is:
%\begin{verbatim}
%    \begin{mplibcode}[instanceName]
%      % some mp code
%    \end{mplibcode}
%\end{verbatim}
%   The behavior is as follows.
%   \begin{itemize}
%   \item  All the variables and functions are shared
%     only among all the environments belonging to the same instance.
%   \item  \cs{mplibcodeinherit} only affects the environments
%     with no instance name set (since if a name is set,
%     the code is intended to be reused at some point).
%   \item |btex| |...| |etex| boxes are also shared and do not
%     require \cs{mplibglobaltextext}.
%   \item  When an instance names is set,
%     respective \cs{currentmpinstancename} is set as well.
%   \end{itemize}
%   In parellel with this functionality, we support
%   optional argument of instance name for \cs{everymplib} and
%   \cs{everyendmplib}, affecting only those |mplibcode| environments
%   of the same name.
%   Unnamed \cs{everymplib} affects not only those instances with no name,
%   but also those with name but with no corresponding \cs{everymplib}.
%   The syntax is:
%\begin{verbatim}
%    \everymplib[instanceName]{...}
%    \everyendmplib[instanceName]{...}
%\end{verbatim}
%
% \subsubsection[\cs{mplibverbatim}]{\cs{mplibverbatim\{enable\textbar disable\}}}
%   \label{sec:mplibverbatim}
%   Default: |disable|.
%   Users can issue \bsx\cs{mplibverbatim\{enable\}}\esx, after which
%   the contents of mplibcode environment will be read verbatim. As a result,
%   except for \cs{mpdim} and \cs{mpcolor} (see \secref{mpdim} and \secref{mpcolor}),
%   all other \TeX\ commands outside of the
%   |btex| or |verbatimtex| |...| |etex| are not expanded and will be fed
%   literally to the \mplib library.
%
% \subsubsection[\cs{mpdim}]{\cs{mpdim\{...\}}}\label{sec:mpdim}
%   Besides other \TeX\ commands, \cs{mpdim} is specially allowed
%   in the mplibcode environment. This feature is inpired by \pkg{gmp} package authored by
%   Enrico Gregorio. Please refer to the manual of \pkg{gmp} package for details.
%\startmpfig
%\mpfig draw origin--(.4\mpdim{\linewidth},0) withpen pencircle scaled 4 dashed evenly scaled 4 withcolor \mpcolor{orange}; \endmpfig
%\stopmpfig{3}
%\begin{verbatim}
%    draw origin--(.4\mpdim{\linewidth},0)
%      withpen pencircle scaled 4 dashed evenly scaled 4
%      withcolor \mpcolor{orange} ;
%\end{verbatim}
%
% \subsubsection[\cs{mpcolor}]{\cs{mpcolor[...]\{...\}}}\label{sec:mpcolor}
%   With \cs{mpcolor} command, color names or expressions of
%   \pkg{color}, \pkg{xcolor} and \pkg{l3color} module/packages can be used in the mplibcode
%   environment (after |withcolor| command, in principle).
%   See the example above at \secref{mpdim}.
%   The optional |[...]| denotes the option of \pkg{xcolor}'s \cs{color} command.
%   For spot colors, \pkg{l3color} module is well supported in PDF and DVI mode.
%   Package \pkg{colorspace} is supported as well in PDF mode,
%   but could conflict with \pkg{luamplib}'s special features such as shading
%   when \cs{DocumentMetadata}, i.e.\ PDF management code, is not loaded.
%
%   \notabene Formerly,
%   only the first object would have been colored as intended
%   among multiple graphical objects in a \metapost image,
%   because \cs{mpcolor} always produced |withprescript| command internally.
%   Since v2.38.1, now that \cs{mpcolor} returns a \metapost color expression if possible,
%   users can issue the sentence as follows
%   without worrying about the location of the color command:
%\startmpfig
%\mpfig draw image (drawarrow (left--right) scaled 5) scaled 8 withcolor \mpcolor{red!50};\endmpfig
%\stopmpfig{2}
%\begin{verbatim}
%    draw image (drawarrow (left--right) scaled 5)
%      scaled 8
%      withcolor \mpcolor{red!50} ;
%\end{verbatim}
%   \notabene Be aware, however, that even after v2.38.1 \cs{mpcolor} still inserts
%   |withprescript| command when the color specified is a spot color
%   (or named color in DVI mode).
%   Users therefore have to revise the code so that the color can have effect inside the image.
%   For instance:
%\begin{verbatim}
%    draw image (drawarrow (left--right) scaled 5)
%      scaled 8
%      withcolor \mpcolor{spotA}
%      withoutcolor ;
%\end{verbatim}
% or preferably,
%\begin{verbatim}
%    draw image (drawarrow (left--right) scaled 5 withcolor \mpcolor{spotA})
%      scaled 8 ;
%\end{verbatim}
%
%
% \subsubsection[\cs{mpfig}, \cs{endmpfig}]{\cs{mpfig ...} \cs{endmpfig}}
%   Besides the |mplibcode| environment (for \LaTeX) and
%   \cs{mplibcode ...} \cs{endmplibcode} (for Plain),
%   we also provide unexpandable \TeX\ macros \cs{mpfig} |...| \cs{endmpfig} and its starred version
%   \cs{mpfig*} |...| \cs{endmpfig} to save typing toil.
%   The former is roughly the same as follows:
%\begin{verbatim}
%    \begin{mplibcode}[@mpfig]
%      beginfig(0)
%        token list declared by \everymplib[@mpfig]
%        ...
%        token list declared by \everyendmplib[@mpfig]
%      endfig;
%    \end{mplibcode}
%\end{verbatim}
%   and the starred version is roughly the same as follows:
%\begin{verbatim}
%    \begin{mplibcode}[@mpfig]
%      ...
%    \end{mplibcode}
%\end{verbatim}
%   In these macros \cs{mpliblegacybehavior\{disable\}}
%   is forcibly declared.
%   Again, as both share the same instance name, \metapost codes are inherited among them.
%   A simple example:
%\startmpfig
%\mpfig* input boxes \endmpfig \mpfig drawoptions(withcolor 1/3[red,white]); circleit.a(btex Box 1 etex); drawboxed(a); \endmpfig
%\stopmpfig{3}
%\begin{verbatim}
%    \everymplib[@mpfig]{ drawoptions(withcolor 1/3[red,white]); }
%    \mpfig* input boxes \endmpfig
%    \mpfig
%      circleit.a(btex Box 1 etex); drawboxed(a);
%    \endmpfig
%\end{verbatim}
%   Users can change the instance name (default value:\ |@mpfig|) by redefining
%   \cs{mpfiginstancename}, after which a new \mplib instance will start and
%   code inheritance too will begin anew.
%   \cs{let}\allowbreak\cs{mpfiginstancename}\allowbreak\cs{empty} will
%   prevent code inheritance if \cs{mplibcodeinherit} is not true.
%
% \subsubsection{About cache files}
%   \label{sec:mplibcachedir}
%   To support |btex| |...| |etex| in external |.mp| files, \pkg{luamplib}
%   inspects the content of each and every |.mp| file and makes caches
%   if nececcsary before returning their paths to the \mplib library.
%   This could waste the compilation time, as most |.mp| files
%   do not contain |btex| |...| |etex| commands.  So \pkg{luamplib} provides
%   macros as follows, so that users can give instructions about files
%   that do not require this functionality.
%   \begin{itemize}
%   \item \cs{mplibmakenocache}|{|\meta{filename}|[,|\meta{filename}|,...]}|
%   \item \cs{mplibcancelnocache}|{|\meta{filename}|[,|\meta{filename}|,...]}|
%   \end{itemize}
%   where \meta{filename} is a filename without |.mp| extension.
%   Note that |.mp| files under |$TEXMFMAIN/|\allowbreak|metapost/|\allowbreak|base| and
%   |$TEXMFMAIN/metapost/context/base| are already registered by default.
%   \notabene \bsx\cs{mplibmakenocache}|{*}|\esx\ will suppress making cache files.
%   Use it at your own risk.
%
%   By default, cache files will be stored in |$TEXMFVAR/luamplib_cache| or,
%   if it's not available (mostly not writable),
%   in the directory where output files are saved:
%   to be specific, |$TEXMF_OUTPUT_DIRECTORY/luamplib_cache|,
%   |./luamplib_cache|, |$TEXMFOUTPUT/luamplib_cache|, and |.|, in this order.
%   |$TEXMF_OUTPUT_DIRECTORY| is normally the value of |--output-directory|
%   command-line option.
%
%   Users can change this behavior by the command
%   \bsx\cs{mplibcachedir}\marg{directory path}\esx, where tilde (|~|) is interpreted
%   as the user's home directory (on a windows machine as well).
%   As backslashes (\cs{}) should be escaped by users, it would be easier to use
%   slashes (|/|) instead.
%
% \subsubsection{About figure box metric}
%   Notice that, after each figure is processed, the macro \cs{MPwidth} stores
%   the width value of the latest figure; \cs{MPheight}, the height value.
%   Incidentally, also note that \cs{MPllx}, \cs{MPlly}, \cs{MPurx}, and
%   \cs{MPury} store the bounding box information of the latest figure
%   without the unit |bp|.
%
% \subsubsection{luamplib.cfg}
%   At the end of package loading, \pkg{luamplib} searches
%   |luamplib.cfg| and, if found, reads the file in automatically.
%   Frequently used settings such as \cs{everymplib}, \cs{mplibforcehmode}
%   or \cs{mplibcodeinherit} are suitable for going into this file.
%
% \subsubsection{Tagged PDF}\label{sec:taggedPDF}
% When \pkg{tagpdf} package is loaded and activated, |mplibcode| environment accepts additional options for tagged PDF\@.
% The code related to this functionality is currently in experimental stage, not guaranteeing backward compatibility.
% Available optional keys are similar to those of the \LaTeX's |picture| environment
% (|texdoc| |latex-lab-graphic|).
% The default tagging mode is the |alt| key with |Figure| structure.
% \begin{description}
% \item[alt=\meta{text}] starts a |Figure| tag by default and
%   sets an alternate text of the figure from the \meta{text}.
%   BBox info will be added automatically to the PDF\@.
%   This key is needed for ordinary \metapost figures, for which,
%   if no |alt| text is given, a default text will be used with a warning issued.
%   You can change the alternate text within \metapost code as well:
%   \bsx|VerbatimTeX| |"\mplibalttext|\marg{text}|";|\esx
% \item[actualtext=\meta{text}] starts a |Span| tag implicitly and sets a
%   replacement text (a.k.a.\ actual text) from the \meta{text}.
%   If in vertical mode, horizontal mode will be forced by \cs{noindent} command.\footnote{\relax
%     It is not recommended to personally redefine \cs{prependtomplibbox}.
%     Apart from using \cs{mplibforcehmode} or \cs{mplibnoforcehmode},
%     the redefinition might be incompatible with |actualtext| key.
%     See \secref{mplibforcehmode} on these commands. }
%   BBox info will not be added.
%   This key is intended for figures which can be represented by a character or
%   a small sequence of characters.
%   You can change the actual text within \metapost code as well:
%   \bsx|VerbatimTeX| |"\mplibactualtext|\marg{text}|";|\esx
% \item[artifact] starts an |Artifact| MC (marked content).
%   BBox info will not be added.
%   This key is intended for decorative figures which have no semantic meaning.
% \item[text] starts an |Artifact| MC but enables tagging on \TeX-text boxes
%   (such as |btex| |...| |etex|, excluding pictures made by |infont| operator).
%   If in vertical mode, horizontal mode will be forced by \cs{noindent} command.\footnote{\relax
%     The key |text| also shares the limitation mentioned in the previous footnote.}
%   BBox info will not be added.
%   This key is intended for figures the meaning of which is the sequence of texts in the
%   \TeX-text boxes in the order they are drawn in the figure.
%
%   \notabene Within |text|-mode figures, reusing \TeX-text boxes is strongly discouraged.
%
%   Note that the text in a \TeX-text box which starts with |[taggingoff]| will not be tagged
%   at all, and
%   of course |[taggingoff]| and its trailing spaces will be gobbled by \pkg{luamplib}.
%   For example, the first and the third boxes in the following figure will not be tagged,
%   and still remain in the |Artifact| MC-chunks.
%\startmpfig
%\mpfig draw btex [taggingoff] $\sqrt 2$ etex; draw textext "$\sqrt 3$" shifted 12down; draw TEX "[taggingoff] $\sqrt 5$" shifted 24down; draw maketext "$\sqrt 7$" shifted 36down; draw mplibgraphictext "$\sqrt x$" shifted 48down; \endmpfig
%\stopmpfig{5}
%\begin{verbatim}
%    \begin{mplibcode}[text]
%      beginfig(1)
%        draw btex [taggingoff] $\sqrt 2$ etex ;
%        draw textext "$\sqrt 3$" shifted 12down ;
%        draw TEX "[taggingoff] $\sqrt 5$" shifted 24down ;
%        draw maketext "$\sqrt 7$" shifted 36down ;
%        draw mplibgraphictext "$\sqrt x$" shifted 48down ;
%      endfig;
%    \end{mplibcode}
%\end{verbatim}
% \item[off] Given this key, nothing will be tagged by \pkg{luamplib}.
% \item[tag=\meta{name}] You can choose a tag name, default value being |Figure|.\relax
%   \footnote{The option |tag=false|, however, is a synonym of the |off| key.}
%   For instance, you can set \bsx|tag=Formula,| |alt=|\meta{text}\esx\ to get
%   a |Formula| element with its alternate text.\footnote{Beware that this bypasses
%     \LaTeX's regular math formula tagging, for which the |text| key is needed.}
% \item[adjust-BBox=\meta{dimens}] You can correct the BBox attribute of the figure
%   by space-separated four dimensional values, which will be added to the
%   automatically calculated BBox values.
%   To draw the bounding box for checking with half-transparent red color, you can add
%   |debug=|\allowbreak|BBox| to the argument of \cs{DocumentMetadata} command.
% \item[tagging-setup=\meta{key-val list}]
%   This key accepts as its value the list of key-value options mentioned so far.
% \end{description}
% You can set these options anywhere in the document by declaring
% \bsx\cs{SetKeys}\allowbreak |[luamplib/tagging]|\allowbreak \marg{key-val list}\esx,
% which will affect \pkg{mplib} figures thereafter in the scope.
% And the options listed above are provided for \cs{mpfig} and \cs{usemplibgroup}
% (see \hyperlink{usemplibgroup}{below} \secref{transparencygroup}) commands as well.
%\begin{verbatim}
%    \begin{mplibcode}[myInstanceName, alt=drawing of a circle]
%      ...
%    \end{mplibcode}
%
%    \mpfig[alt=drawing of a square box]
%      ...
%    \endmpfig
%
%    \mppattern{...}           % see below
%      \mpfig[off]             % do not tag this figure
%        ...
%      \endmpfig
%    \endmppattern
%
%    \mplibgroup{...}          % see below
%      \mpfig[off]             % do not tag this figure
%        ...
%      \endmpfig
%    \endmplibgroup
%
%    \usemplibgroup[alt=drawing of a triangle]{...}
%\end{verbatim}
% As for the instance name of |mplibcode| environment,
% \bsx|instance=|\meta{name}\esx\ or \bsx|instancename=|\allowbreak\meta{name}\esx\ is also allowed
% in addition to the raw instance name as shown above.
%
%
% \subsection{\textsc{MetaPost}}
%
% \subsubsection[\ttfamily mplibdimen, mplibcolor]{\ttfamily mplibdimen ..., mplibcolor ...}
%   \bsx|mplibdimen| \meta{string}\esx\ and \bsx|mplibcolor| \meta{string}\esx\
%   are \metapost interfaces for the \TeX\ commands
%   \cs{mpdim} and \cs{mpcolor} (see above \secref{mpdim} and \secref{mpcolor}). For example,
%   |mplibdimen| |"\linewidth"| is basically the same as \cs{mpdim\{\cs{linewidth}\}}, and
%   |mplibcolor| |"red!50"| is basically the same as \cs{mpcolor\{red!50\}}.
%   The difference is that these \metapost operators can also be used in external |.mp| files,
%   which cannot have \TeX\ commands outside of the |btex| or |verbatimtex| |...| |etex|.
%
% \subsubsection[\ttfamily mplibtexcolor, mplibrgbtexcolor]{\ttfamily mplibtexcolor ..., mplibrgbtexcolor ...}
%   \label{sec:mplibtexcolor}
%   \bsx|mplibtexcolor| \meta{string}\esx\ is a \metapost operator that converts a \TeX\ color expression
%   to a \metapost color expression, that can be used anywhere color expression is expected
%   as well as after the |withcolor| command.\footnote{\relax
%     Since v2.38.1, the operation of |mplibtexcolor| is the same as that of |mplibcolor|
%     if the color specified is not a spot color or a named color in DVI mode.
%   }
%   For instance:
%\begin{verbatim}
%    color col;
%    col := mplibtexcolor "olive!50";
%\end{verbatim}
%   But the result may vary in its color model (gray/rgb/cmyk)
%   according to the given \TeX\ color.
%   Therefore the example shown above would raise a \metapost error:
%   |cmykcolor col;| should have been declared.
%   By contrast, \bsx|mplibrgbtexcolor| \meta{string}\esx\ always returns rgb-model expressions.
%
%   \notabene Spot colors are forced to cmyk or rgb model,
%   so these operators are not recommended for spot colors.
%
% \subsubsection[\ttfamily withmplibcolors]{\ttfamily withmplibcolors (..., ...)}
%   \label{sec:withmplibcolors}
%   Unlike the |withcolor| command, users can specify one color for filling
%   and another color for stroking using the macro |withmplibcolors| at the end of a sentence.
%   The syntax is \bsx|withmplibcolors| |(|\meta{fill color expr}|,| \meta{stroke color expr}|)|\esx.
%   When the argument is in string type, it is regarded as the color expression of \TeX\ side.
%   A simple example (see also the example at \secref{mplibdrawglyph}):
%\startmpfig
%\mpfig filldraw fullcircle scaled 40 withpen pencircle scaled 2 withmplibcolors ("orange!60", 2/3red); \endmpfig
%\stopmpfig{2}
%\begin{verbatim}
%    filldraw fullcircle scaled 40
%      withpen pencircle scaled 2
%      withmplibcolors ("orange!60", 2/3red) ;
%\end{verbatim}
%   The PDF file size is much smaller than issueing two sentences with different colors,
%   though the apparent effect is the same.
%
% \subsubsection[\ttfamily withtransparency]{\ttfamily withtransparency (..., ...)}
%   \label{sec:luamplibtransparency}
%   \bsx|withtransparency(|\meta{number} \textbar\ \meta{string}|,| \meta{numeric}|)|\esx\
%   is provided for \emph{plain} format as well as \emph{metafun}.
%   The first argument accepts a number or a name among
%   alternative transparency methods (see |texdoc| |metafun| \S\,8.2 Figure~8.1).
%   The second argument accepts a numeric expression denoting opacity.
%\startmpfig
%\mpfig fill unitsquare scaled 40 withcolor 1/3[blue,white] withtransparency(1,0.5); fill fullcircle scaled 40 withcolor 1/3[red,white] withtransparency (1,0.5); \endmpfig
%\stopmpfig{6}
%\begin{verbatim}
%    \mpfig
%      fill unitsquare scaled 40
%        withcolor 1/3[blue,white]
%        withtransparency (1, 0.5)           % or ("normal", 0.5)
%        ;
%      fill fullcircle scaled 40
%        withcolor 1/3[red,white]
%        withtransparency (1, 0.5)
%        ;
%    \endmpfig
%\end{verbatim}
%
% \subsubsection[\ttfamily withmplibopacities]{\ttfamily withmplibopacities (..., ..., ...)}
%   \label{sec:withmplibopacities}
% By analogy with the macro |withmplibcolors| (see above \secref{withmplibcolors}),
% the macro |withmplibopacities| is also provided.
% The syntax is \bsx|withmplibopacities|
% |(|\meta{number} \textbar\ \meta{string}|,| \meta{numeric}, \meta{numeric}|)|\esx.
% The first argument is the same as that of |withtransparency| command
% described above at \secref{luamplibtransparency};
% the latter two arguments are numeric expressions denoting
% \emph{fill opacity} and \emph{stroke opacity} respectively.
% It is more efficient than issueing two sentences with different opacities.
%\startmpfig
%\mpfig pickup pencircle scaled 2; filldraw unitsquare scaled 40 withcolor 1/3[blue,white] withmplibopacities (1, 1/2, 1); filldraw fullcircle scaled 40 withcolor 1/3[red,white] withmplibopacities (1, 1/2, 1); \endmpfig
%\stopmpfig{6}
%\begin{verbatim}
%    \mpfig
%      pickup pencircle scaled 2;
%      filldraw unitsquare scaled 40
%        withcolor 1/3[blue,white]
%        withmplibopacities (1, 1/2, 1)      % or ("normal", 1/2, 1)
%        ;
%      filldraw fullcircle scaled 40
%        withcolor 1/3[red,white]
%        withmplibopacities (1, 1/2, 1)
%        ;
%    \endmpfig
%\end{verbatim}
%
% \subsubsection[\ttfamily withshadingmethod]{\ttfamily ... withshadingmethod ...}
%   \label{sec:luamplibshading}
%   The syntax is exactly the same as \emph{metafun}'s new shading method (|texdoc metafun| \S\,8.3.3), except that
%   the `|shade|' contained in each and every macro name has changed to
%   `|shading|' in \pkg{luamplib}: for instance, while |withshademethod| is
%   a macro name which only works with \emph{metafun} format,
%   the equivalent provided by \pkg{luamplib}, |withshadingmethod|, works with \emph{plain} as well.
%   Other differences to the \emph{metafun}'s and some cautions are:
%   \begin{itemize}
%   \item \emph{Textual pictures} as well as paths can have shading effect.
%     The term \emph{textual picture} here means
%     a picture generated by |btex| |...| |etex|, |textext|, |TEX|, |maketext|,
%     |mplibgraphictext| (see below \secref{mplibgraphictext}), or |infont| operator,
%     though technically only the last one is a true textual picture.
%     Note that the picture, including transparency group,
%     in which the objects are filled \emph{without} color
%     can also be regarded as a textual picture.\footnote{\relax
%       See below \secref{mplibdrawglyph},
%       particularly the first \hyperlink{firstpatternexample}{example} of tiling pattern
%       at \secref{mppattern}.
%       See also \secref{transparencygroup} and \secref{mplibgroupendmplibgroup},
%       particularly the example in the \hyperlink{para:pictureshading}{note}
%       about picture shading and transparency group.}
%\startmpfig
%\mpfig draw btex \bfseries\TeX etex rotated 15 scaled 6 withshadingmethod "linear" withshadingvector (0,3) withshadingstep ( withshadingfraction 1/2 withshadingcolors (red,green)) withshadingstep ( withshadingfraction 1 withshadingcolors (green,blue)); \endmpfig
%\stopmpfig{6}
%\begin{verbatim}
%    draw btex \bfseries\TeX etex rotated 15 scaled 6
%      withshadingmethod "linear"
%      withshadingvector (0,3)
%      withshadingstep (
%        withshadingfraction 1/2
%        withshadingcolors (red,green)
%      )
%      withshadingstep (
%        withshadingfraction 1
%        withshadingcolors (green,blue)
%      ) ;
%\end{verbatim}
%   \item When shading a picture generated by `|infont|' operator or that has multiple components,
%     the effect of |withshadingvector| and that of |withshadingdirection| will be the same,
%     as \pkg{luamplib} considers only the bounding box of the picture.
%   \item A few more optional macros are available in addition to the \emph{metafun}'s:
%    |withshadingpoints|, |withshadingcenters|, |withshadingextend|, |withshadingmatrix|,
%    and |withshadingstroke|.
%   \end{itemize}
% The syntax is \bsx\meta{path} \textbar\ \meta{textual picture} |withshadingmethod| \meta{string}\esx,
% where the latter shall be either |"linear"| or |"circular"|.
% The balance of this subsection is to explain additional optional macros.
% Above all, there are two ways in specifying the shading coordinates, of which
% you can choose the more convenient one.
% First, the way that mimicks the \emph{metafun}'s:
% \begin{description}
%   \item[withshadingvector \meta{pair}]
%     Starting and ending points (as time value) on the path.
%   \item[withshadingdirection \meta{pair}]
%     Starting and ending points (as time value) on the bounding box,
%     default value being |(0,2)|.
%   \item[withshadingorigin \meta{pair}]
%     The center of both starting and ending circles,
%     default value being |center p|, where |p| is the operand of |withshadingmethod|.
%   \item[withshadingcenter \meta{pair}]
%     Value to specify the starting center.
%     For instance,
%     |(0,0)| means that the center of starting circle is |center p|;
%     |(1,1)| means |urcorner p|; |(-1,-1)| means |llcorner p|.
%   \item[withshadingradius \meta{pair}]
%     Radii of starting and ending circles. This is no-op in linear mode.
%     Default value: |(0,| |abs(center p -| |urcorner p))|
%   \item[withshadingfactor \meta{numeric}]
%     Multiplier of the radii, default value being |1.2|.
%     This is no-op in linear mode.
%   \item[withshadingtransform \meta{string}]
%     where \meta{string} shall be |"yes"| (respect transform) or |"no"| (ignore transform).
%     Default value: |"no"| for pictures made by |infont| operator or having multiple components;
%     |"yes"| for all other cases.
% \end{description}
% Secondly, the way provided by \pkg{luamplib} only:
% \begin{description}
%   \item[withshadingpoints (\meta{pair}, \meta{pair})]
%     In linear mode, values to specify directly the starting and ending points:
%     you can use it instead of |withshadingvector| or |withshadingdirection|.
%     In circular mode, the centers of starting and ending circles:
%     it could be easier than issueing two macros
%     |withshadingorigin| and |withshadingcenter|.
%     Note that, within the macro, both \bsx|withshadingfactor| |1|\esx\ and
%     \bsx|withshadingtransform| |"no"|\esx\ are already decalred.
%   \item[withshadingcenters (\meta{pair}, \meta{pair})]
%     Synonym of |withshadingpoints|.
%     Normally accompanied by |withshadingradius| which has the same meaning as described above.
% \end{description}
% Now, optional macros common to the both ways:
% \begin{description}
%   \item[withshadingstep (|...|)]
%     For combined shading of more than two colors.
%   \item[withshadingfraction \meta{numeric}]
%     Fractional number of each shading step,
%     and so only meaningful within |withshadingstep|.
%   \item[withshadingcolors (\meta{color expr}, \meta{color expr})]
%     Starting and ending colors,
%     default value being |(white,| |black)|.
%     String-type argument is regarded as the color expression of \TeX\ side.
%   \item[withshadingdomain \meta{pair}]
%     Limiting values of parametric variable
%     that varies on the axis of color gradient,
%     default value being |(0,1)|. Of course the values can be negative or greater than $1$.
%   \item[withshadingextend (\meta{boolean}, \meta{boolean})]
%     Values specifying whether to extend the shading
%     beyond the starting and ending points or circles, default value being |(true,| |true)|.
%     An example just to show the concept:
%\startmpfig
%\mpfig path p[]; p1 = fullcircle scaled 50; p2 = fullcircle scaled 50 shifted 40right; fill (subpath (2,6) of p1 -- subpath (-2,2) of p2 -- cycle) rotated 10 withshadingmethod "circular" withshadingcenters (center p1, center p2 rotated 10) withshadingradius (25,25) withshadingcolors (3/4[red,white], red) withshadingextend (false, false) ; \endmpfig
%\stopmpfig{8}
%\begin{verbatim}
%    \mpfig
%      path p[];
%      p1 = fullcircle scaled 50;
%      p2 = fullcircle scaled 50 shifted 40 right;
%      fill (subpath (2,6) of p1 -- subpath (-2,2) of p2 -- cycle) rotated 10
%        withshadingmethod  "circular"
%        withshadingcenters (center p1, center p2 rotated 10)
%        withshadingradius  (25, 25)
%        withshadingcolors  (3/4[red,white], red)
%        withshadingextend  (false, false) ;
%    \endmpfig
%\end{verbatim}
%   \item[withshadingmatrix \meta{string}]
%     \metapost code for transformation of shading, such as |"xscaled 1.2| |yscaled 0.8"|;
%     or six numerics separated by spaces, such as |"1.2 0 0 0.8 0 0"|.
%     Only meaningful when the object is a \meta{picture}.
%   \item[withshadingstroke \meta{string}]
%     where \meta{string} shall be |"yes"| or |"no"|.
%     Only meaningful when the shading object is a \meta{path};
%     if |"yes"|, we get the path stroked and \emph{then} shaded.
%     It is more efficient than issueing two sentences.
% \end{description}
%
% \subsubsection[\ttfamily withfademethod]{\ttfamily ... withfademethod ...}
%   This is a \metapost command which makes the color of an object gradiently transparent,
%   a.k.a.\ \emph{fading}.
%   The syntax is \bsx\meta{path} \textbar\ \meta{picture} |withfademethod| \meta{string}\esx,
%   the latter being either |"linear"| or |"circular"|.
%   Though it is similar to the |withshademethod| from \emph{metafun},
%   the differences are: (1)~the object of fading can be a picture as well as a path;
%   (2)~you cannot make gradient colors, but can only make gradient opacity.
%   Technically speaking, this command generates and applies a special kind of
%   masking transparency group described below at \secref{withmaskinggroup}.
%
%   Related macros to control optional values are:
%   \begin{description}
%   \item [withfadeopacity (\meta{numeric}, \meta{numeric})]
%     sets the starting opacity and the ending opacity, default value being |(1,0)|.
%     `|1|' denotes full color; `|0|' full transparency.
%   \item [withfadevector (\meta{pair}, \meta{pair})]
%     sets the starting and ending points. Default value in the linear mode is
%     |(llcorner p,| |lrcorner p)|, where |p| is the operand,
%     meaning that fading starts from the left edge and ends at the right edge.
%     Default value in the circular mode is |(center p,| |center p)|, which means
%     centers of both starting and ending circles are the center of the bounding box.
%   \item [withfadecenter] is a synonym of |withfadevector|.
%   \item [withfaderadius (\meta{numeric}, \meta{numeric})]
%     sets the radii of starting and ending circles. This is no-op in the linear mode.
%     Default value is |(0, abs(center p - urcorner p))|, meaning that fading starts from the
%     center and ends at the four corners of the bounding box.
%   \item [withfadestep (|...|)]
%     for combined fading of more than two opacities.
%   \item [withfadefraction \meta{numeric}]
%     Fractional number of each fading step. Only meaningful within |withfadestep|.
%   \item [withfadeextend (\meta{boolean}, \meta{boolean})]
%     specifies whether to extend the fading
%     beyond the starting and ending points or circles, default value being |(true,| |true)|.
%   \item [withfadematrix \meta{string}]
%     \metapost code for transformation of fading, such as |"xscaled 1.2| |yscaled 0.8"|;
%     or six numerics separated by spaces, such as |"1.2 0 0 0.8 0 0"|.
%   \item [withfadebbox (\meta{pair}, \meta{pair})]
%     sets the bounding box of the fading area, default value being |(llcorner p,| |urcorner p)|.
%     Though this option is not needed in most cases, there could be cases when users want to
%     explicitly control the bounding box.
%     Particularly, see the description \hyperlink{withgroupbbox}{below}
%     at \secref{transparencygroup} on the analogous macro |withgroupbbox|.
%   \end{description}
%   An example:
%\startmpfig
%\mpfig draw btex \includegraphics[width=100bp]{mill} etex withfademethod  "circular" withfaderadius (20, 50) withfadeopacity (1, 0); \endmpfig
%\stopmpfig{3}
%\begin{verbatim}
%    draw
%      btex \includegraphics[width=100bp]{mill} etex
%      withfademethod  "circular"
%      withfaderadius  (20, 50)
%      withfadeopacity (1, 0) ;
%\end{verbatim}
%
% \subsubsection[\ttfamily mplibgraphictext]{\ttfamily mplibgraphictext ...}
%     \label{sec:mplibgraphictext}
%   \bsx|mplibgraphictext| \meta{string}\esx\ is a \metapost operator,
%   the effect of which is similar to that of
%   \ConTeXt's |graphictext| or our own |mpliboutlinetext|
%   (see below \secref{mpliboutlinetext}).
%   However the syntax is somewhat different.
%\startmpfig
%\mpfig draw mplibgraphictext "$\sqrt{2+x}$" rotated 10 scaled 3 fakebold 2.5 fillcolor "red!50" drawcolor 2/3 red; \endmpfig
%\stopmpfig{3}
%\begin{verbatim}
%    draw mplibgraphictext "$\sqrt{2+x}$"
%      rotated 10 scaled 3
%      fakebold 2.5                           % fontspec option
%      fillcolor "red!50"                     % color expression
%      drawcolor 2/3 red                      % or strokecolor 2/3 red
%      ;
%\end{verbatim}
%   |fakebold|, |fillcolor| and |drawcolor| (or |strokecolor|) are optional;
%   default values are |2|, |"white"| and |"black"| respectively.\footnote{Users can
%     use the |withmplibcolors| macro instead of |fillcolor| and |drawcolor| options.
%     See \secref{withmplibcolors} on this macro.}
%   When the color expression is given in string type, it is regarded as
%   \pkg{color}, \pkg{xcolor} or \pkg{l3color}'s expression.
%   All from |mplibgraphictext| to the end of sentence will compose an
%   anonymous picture, which can be drawn or assigned to a variable.
%   Incidentally, |withfillcolor| and |withdrawcolor| are synonyms of
%   |fillcolor| and |drawcolor|, hopefully to be compatible with |graphictext|.
%
%   \notabene
%   In some cases,
%   especially when processing complicated \TeX\ code,
%   |mplibgraphictext| will produce better results than \ConTeXt\
%   or even than our own |mpliboutlinetext|, not to mention the much smaller PDF file size.
%   There are, however, some limitations such that you can't
%   apply shading (gradient colors) to the text with \emph{metafun}'s |withshademethod|.\relax
%   \footnote{But this limitation is now lifted by the introduction of |withshadingmethod|.
%     See above \secref{luamplibshading}.}
%   Again,
%   in DVI mode, \pkg{unicode-math} package is needed for math formulae,
%   as we cannot embolden type1 fonts in DVI mode.
%   But the most critical limitation is that, unlike |mpliboutlinetext|,
%   you cannot manipulate the shape of outline paths,
%   because the returned picture is basically a |btex| |...| |etex| picture.
%
%   \subsubsection[\ttfamily mplibglyph]{\ttfamily mplibglyph ... of ...}
%   \metapost operator \bsx|mplibglyph|
%   \meta{number} \textbar\ \meta{string} |of| \meta{number} \textbar\ \meta{string}\esx\
%   returns a \metapost picture
%   containing outline paths of a glyph in OpenType, TrueType or Type1 (|.pfb|) fonts.
%   When a TFM font is specified, \metapost primitive |glyph| will be called.
%\begin{verbatim}
%    mplibglyph 50  of \fontid\font           % slot 50 of current font
%    mplibglyph "Q" of "TU/TeXGyrePagella(0)/m/n/10"      % font csname
%    mplibglyph "Q" of "texgyrepagella-regular.otf"       % raw filename
%    mplibglyph "R" of "utmr8a.pfb"                       % raw filename (type1 font)
%    mplibglyph "Q" of "Times.ttc(2)"                     % subfont number
%    mplibglyph "Q" of "SourceHanSansK-VF.otf[Regular]"   % instance name
%    mplibglyph "R" of "SourceHanSansK-VF.otf[wght=800]"  % axis names & values
%\end{verbatim}
%   Both arguments before and after `|of|' can be either a number or a string.
%   Number arguments are regarded as a glyph slot (GID) and a font id number, repectively.
%   String argument at the left side is regarded as a glyph name in the font or a unicode character.
%   String argument at the right side is regarded as a \TeX\ font csname (without backslash) or
%   the raw filename of a font. When it is a font filename, a number within parentheses
%   after the filename denotes a
%   subfont number (starting from zero) of a TTC font; a string within brackets denotes
%   an instance name, or names and values for |axis| feature, of a variable font.
%
%   \notabene Regrettably we have some bug in processing
%   not a few glyphs in |cmr10.pfb| and its family (or maybe other) Type1 fonts.\relax
%     \footnote{The bug seems to be fixed in |font-cff.lmt| contained in \ConTeXt mkxl, but
%     current \pkg{luaotfload} is based on |font-cff.lua| from \ConTeXt mkiv.
%     As you see, |mplibglyph| operator requires \pkg{luaotfload} package loaded,
%     which however is done automatically by \LaTeX\ format.}
%   If that happens, consider using |glyph| operator instead of |mplibglyph|.
%
%   \subsubsection[\texttt{mplibdrawglyph}, and its friends]{\ttfamily mplibdrawglyph ...,
%     mplibstrokeglyph ..., mplibfillandstrokeglyph ...}
%     \label{sec:mplibdrawglyph}
%   As the structure of the picture returned by |mplibglyph| is quite similar to
%   the result of |glyph| primitive,
%   \metapost's |draw| command will fill the inner path of the picture with the background color.
%   In contrast, \bsx|mplibdrawglyph| \meta{picture}\esx\ command fills the paths
%   according to the nonzero winding number rule.
%   As a result, for instance, the area surrounded by inner path of ``O'' will remain transparent.
%
%   \notabene
%   To apply the nonzero winding number rule to a picture containing paths,
%   \pkg{luamplib} appends |withpostscript| |"collect"|
%   to the paths except the last one in the picture.
%   If you want the even-odd rule instead, you can
%   additionally declare |withpostscript| |"evenodd"| to the last path.
%
%   \notabene
%   By the way, when you want fill-and-stroke effect,
%   issueing |filldraw| command to the last path will not always produce what you want:
%   in such cases, you have to issue the command
%   |draw| \meta{the last path} |withpostscript| |"both"|
%   (or |"eoboth"| to apply even-odd rule).\footnote{\emph{metafun} provides macros
%     |nofill|, |eofill|, |fillup|, |eofillup| etc.\ (see \emph{metafun} manual \S\,2.11),
%     which \pkg{luamplib} with \emph{plain} format does not provide currently. }
%
%   As this could be somewhat annoying to users, \pkg{luamplib} v2.38.0 or later provides the following commands as well:
%   \bsx|mplibfillandstrokeglyph| \meta{picture}\esx, \bsx|mplibstrokeglyph| \meta{picture}\esx,
%   and \bsx|mplibfillglyph| \meta{picture}\esx, the last one being a synonym of |mplibdrawglyph| command.
%
%   An example:
%\startmpfig
%\mpfig mplibfillandstrokeglyph mplibglyph "R" of \fontid\font scaled 1/12 withpen pencircle scaled 1 withmplibcolors ("orange", 2/3red); \endmpfig
%\stopmpfig{3}
%\begin{verbatim}
%    mplibfillandstrokeglyph
%      mplibglyph "R" of \fontid\font scaled 1/12
%      withpen pencircle scaled 1
%      withmplibcolors ("orange", 2/3red) ;
%\end{verbatim}
%
%
% \subsubsection[\ttfamily mpliboutlinetext]{\ttfamily mpliboutlinetext (...)}
%   \label{sec:mpliboutlinetext}
%   As said before at \secref{mplibsetformat}, \pkg{luamplib} provides
%   the \metapost operator \bsx|mpliboutlinetext| |(|\meta{string}|)|\esx\ which mimicks
%   \emph{metafun}'s |outlinetext|,
%   but with some enhancements including the support for right-to-left writing direction.
%   The syntax is the same as that of \emph{metafun}: see the \emph{metafun}
%   documentation \S\,8.7 (|texdoc| |metafun|).
%
%   A simple example:
%\startmpfig
%\mpfig draw mpliboutlinetext.b ("$\sqrt{2+\alpha}$") (withcolor \mpcolor{red!50}) (withpen pencircle scaled .25 withcolor 2/3red) scaled 3; \endmpfig
%\stopmpfig{2}
%\begin{verbatim}
%    draw mpliboutlinetext.b ("$\sqrt{2+\alpha}$")
%      (withcolor \mpcolor{red!50})
%      (withpen pencircle scaled .25 withcolor 2/3red)
%      scaled 3 ;
%\end{verbatim}
%   After the process, |mpliboutlinepic[]|
%   and |mpliboutlinenum| will be preserved as global variables;
%   |mpliboutlinepic[1]| |...| |mpliboutlinepic[mpliboutlinenum]|
%   will be an array of images, each of which containing outline paths of a glyph or a rule.
%
%   \notabene As Unicode grapheme cluster is not considered in the array, a unit that must be
%   a single cluster might be separated apart.
%
% \subsubsection[\cs{mppattern}, \ttfamily withmppattern]{\cs{mppattern\{...\} ...}
%   \cs{endmppattern}, \ttfamily ... withmppattern ...}
%   \label{sec:mppattern}
%   \TeX\ macros
%   \bsx\cs{mppattern}\marg{name}\esx\ |...| \bsx\cs{endmppattern}\esx\ define a tiling pattern cell
%   associated with the \meta{name}.
%   \metapost command |withmppattern|, the syntax being
%   \bsx\meta{cyclic path} \textbar\ \meta{textual picture} |withmppattern| \meta{string}\esx, will fill
%   the given path or text with the tiling pattern cell of the \meta{name}
%   by replicating it horizontally and vertically.\footnote{\relax
%     |withpattern| is an operator virtually the same as |withmppattern|,
%     but the former forces a \metapost picture. Therefore
%     you cannot but use |draw| command with |withpattern| operator.
%     On the other hand,
%     \meta{cyclic path} |withmppattern| \meta{string} works as intended
%     only with |fill| or |filldraw| command.
%   }
%   As said before at \secref{luamplibshading},
%   the \emph{textual picture} here means basically any text typeset by \TeX, mostly the result
%   of the |btex| command (and its derivatives) or the |infont| operator.
%
%   An \hypertarget{firstpatternexample}{example}:
%\begin{verbatim}
%    \mppattern{mypatt}               % or \begin{mppattern}{mypatt}
%      [                              % options: see below
%        xstep = 10,
%        ystep = 7,
%        matrix = "rotated 45",       % or "0.7 0.7 -0.7 0.7" or {0.7, 0.7, -0.7, 0.7}
%      ]
%      \mpfig                         % or any other TeX code
%        draw (up--down) scaled 5
%          withcolor 2/3[blue,white] ;
%        draw (left--right) scaled 5
%          withcolor 2/3[red,white] ;
%      \endmpfig
%    \endmppattern                    % or \end{mppattern}
%\end{verbatim}
%\startmpfig
%\mppattern{mypatt}[xstep=10, ystep=7, matrix="rotated 45",]\mpfig draw (up--down) scaled 5 withcolor 2/3[blue,white]; draw (left--right) scaled 5 withcolor 2/3[red,white];\endmpfig\endmppattern
%\mpfig mplibdrawglyph image(draw fullcircle scaled 100; draw reverse fullcircle scaled 40;) withmppattern "mypatt" withpen pencircle scaled 1 withcolor \mpcolor{red!50!blue!50}; \endmpfig
%\stopmpfig{4}
%\begin{verbatim}
%    \mpfig
%      mplibdrawglyph image(
%          draw fullcircle scaled 100;
%          draw reverse fullcircle scaled 40;
%        )
%        withmppattern "mypatt"
%        withpen pencircle scaled 1
%        withcolor \mpcolor{red!50!blue!50} ;
%    \endmpfig
%\end{verbatim}
%
%   The available options, actually elements of a Lua \emph{table},
%   are listed in Table~\ref{tab:mppatternoptions}.
%   For the sake of convenience, the width and height values of the tiling pattern cell will be written down
%   into the log file (depth is always zero). Users can refer to them for option setting.
%
%   \begin{table}
%   \centering
%   \caption{options for \cs{mppattern}}\label{tab:mppatternoptions}
%   \begin{tabular}{lll}\hline
%     Key   & Value Type & Explanation\\\hline
%     |xstep|    &\emph{number} & horizontal spacing between pattern cells\\
%     |ystep|    &\emph{number} & vertical spacing between pattern cells\\
%     |xshift|   &\emph{number} & horizontal shifting of pattern cells\\
%     |yshift|   &\emph{number} & vertical shifting of pattern cells\\
%     |bbox|     &\emph{table} or \emph{string} & |llx|, |lly|, |urx|, |ury| values\kern1pt*\\
%     |matrix|   &\emph{table} or \emph{string} & |xx|, |yx|, |xy|, |yy| values\kern1pt* or MP transform code\\
%     |resources|&\emph{string} & PDF resources if needed\\
%     |colored| or |coloured| &\emph{boolean}& |false| for uncolored pattern. default: |true|\\\hline
%                &                & \small *\,in string type, numbers are separated by spaces\\
%   \end{tabular}
%   \end{table}
%
%   As for |matrix| option, \metapost code such as |"rotated 30 slanted .2"| is allowed as well
%   as the string or table of four numbers. You can also set |xshift| and |yshift|
%   values by using `|shifted|' operator. But when |xshift| or |yshift| option is explicitly
%   given, they have precedence over the effect of `|shifted|' operator.
%
%   When you use special effect such as transparency in a pattern cell,
%   |resources| option is needed: for instance, |resources="/ExtGState| |<</MyObj| |5 0 R>>"|.
%   However, as \pkg{luamplib} automatically includes the resources of the current page, this option
%   is not needed in most cases.
%
%   Option \bsx|colored=false|\esx\ (or |coloured=false|) will generate an uncolored pattern cell which
%   shall have no color at all (i.e.\ |withoutcolor| command is needed for \metapost code).\relax
%   \footnote{When using DVI mode, |-c| option might be needed to the |dvipdfmx| command.}
%   Uncolored pattern will be painted later by the color of a \metapost object.
%   An example:
%\startmpfig
%\begin{mppattern}{pattnocolor}[colored=false, matrix="slanted .3 rotated 15",]\tiny\TeX\end{mppattern}
%\mpfig picture tex; tex = mpliboutlinetext("\bfseries \TeX"); for i=1 upto mpliboutlinenum: mplibfillandstrokeglyph mpliboutlinepic[i] scaled 8 withmppattern "pattnocolor" withpen pencircle scaled 1/2 withcolor (i/4)[red,blue]; endfor \endmpfig
%\stopmpfig{15}
%\begin{verbatim}
%    \begin{mppattern}{pattnocolor}
%      [
%        colored = false,
%        matrix = "slanted .3 rotated 15",
%      ]
%      \tiny\TeX
%    \end{mppattern}
%
%    \begin{mplibcode}
%      beginfig(1)
%        picture tex;
%        tex = mpliboutlinetext ("\bfseries \TeX");
%        for i=1 upto mpliboutlinenum:
%          mplibfillandstrokeglyph mpliboutlinepic[i]
%            scaled 8
%            withmppattern "pattnocolor"
%            withpen pencircle scaled 1/2
%            withcolor (i/4)[red,blue]      % paints the pattern
%            ;
%        endfor
%      endfig;
%    \end{mplibcode}
%\end{verbatim}
% A much simpler and efficient way to obtain a similar result
% (but without colorful characters in this example)
% is to give a \emph{textual picture} as the operand of |withmppattern|:
%\startmpfig
%\mpfig draw mplibgraphictext "\bfseries\TeX" fakebold 1/2 rotated 10 scaled 8 withmppattern "pattnocolor" withmplibcolors(2/3[red,white], 2/3red); \endmpfig
%\stopmpfig{7}
%\begin{verbatim}
%    \begin{mplibcode}
%      beginfig(2)
%        draw mplibgraphictext "\bfseries\TeX"
%          fakebold 1/2
%          rotated 10 scaled 8
%          withmppattern "pattnocolor"
%          withmplibcolors (
%            2/3[red,white],                % paints the pattern
%            2/3 red
%          ) ;
%      endfig;
%    \end{mplibcode}
%\end{verbatim}
%
% \subsubsection[\ttfamily asgroup]{\ttfamily ... asgroup ...}\label{sec:transparencygroup}
% As said \hyperlink{metafunformat}{before} at \secref{mplibsetformat},
% transparency group is available with \emph{plain} as well as \emph{metafun}.
% It is called \emph{Transparency Group} because the objects contained in the group are composited
% to produce a single object, so that outer transparency effect, if any,
% will be applied to the group as a whole, not to the individual objects cumulatively.
%
% The syntax is basically the same as \emph{metafun}'s:
% \bsx\meta{picture} \textbar\ \meta{path} |asgroup| \meta{string}\esx, the latter being
% |""| (empty string)
% or any comma-separated combination of |isolated|, |knockout|, |wrapped| and |off|
% (for example, |"isolated,knockout,wrapped"|),
% which will return a \metapost picture.
% The additional features provided by \pkg{luamplib} are:
% \begin{itemize}
% \item As mentioned, in addition to those arguments mimicking \emph{metafun}'s,
%   we allow other optional arguments at the right-hand side:
%   \begin{itemize}
%   \item |asgroup| |"off"| will produce an ordinary \emph{form XObject}
%     rather than a transparency group XObject.
%     By contranst, a transparency group will be produced
%     when `|off|' is not given, including |""| (empty string)
%     in which case both of the PDF keys |/I| and |/K| are |false|.
%   \item |asgroup| |"wrapped"| will produce a transparency group XObject
%     in which an ordinary form XObject is wrapped up.
%     This option could be useful when a picture shading (\emph{shading pattern} in technical terms)
%     is used in the object of |asgroup|.
%     See the note about picture shading described \hyperlink{para:pictureshading}{below}.
%   \end{itemize}
% \item You can reuse the XObject as many times as you want
%   in the \TeX{} code or in other \metapost code chunks,
%   with infinitesimal increase in the size of PDF file.
%   For this functionality we provide \TeX{} and \metapost macros as follows:
% \end{itemize}
% \begin{description}
% \item[withgroupname \meta{string}] associates an XObject with the given name.
%   When this command is not appended to the sentence with |asgroup| operator,
%   the default name `|lastmplibgroup|' will be used.
%
% \item[\textbackslash usemplibgroup\marg{name}]
%   \hypertarget{usemplibgroup}{}\relax
%   is a \TeX\ command to reuse an XObject of the name
%   once used.
%   Note that the position of the XObject will be origin-based:
%   in other words, lower-left corner of the bounding box will be shifted to the origin.
%
% \item[usemplibgroup \meta{string}] is a \metapost command which will add
%   an XObject of the name to the |currentpicture|.
%   Contrary to the \TeX\ command just mentioned,
%   the position of the XObject is the same as the original XObject.
%
% \item[withgroupbbox (\meta{pair}, \meta{pair})]
%   \hypertarget{withgroupbbox}{}\relax
%   sets the bounding box of the XObject,
%   default value being |(llcorner p, urcorner p)|.
%   This option might be needed especially when you draw with a thick pen
%   a path that touches the boundary;
%   you would probably want to append to the sentence
%   `|withgroupbbox| |(bot| |lft| |llcorner| |p,| |top| |rt| |urcorner| |p)|',
%   supposing that the pen was selected by the |pickup| command.
%
% \end{description}
% An example showing the effect of transparency group and
% the difference between the \TeX\ and \metapost commands:
%\startmpfig
%   \hypertarget{noasgroupexample}{}\relax
%\mpfig picture pic; pic = image(drawarrow (left--right) scaled 5 withcolor red) scaled 10; draw pic asgroup "off" withtransparency (1, 1/2);\endmpfig
%\stopmpfig{5}
%\begin{verbatim}
%    \mpfig
%      picture pic;
%      pic = image(drawarrow (left--right) scaled 5 withcolor red) scaled 10 ;
%      draw pic
%        asgroup "off"
%        withtransparency (1, 1/2) ;
%    \endmpfig
%\end{verbatim}
%\startmpfig
%\mpfig draw pic asgroup "" withgroupname "mygroup" withtransparency (1, 1/2); draw (left--right) scaled 5; draw (up--down) scaled 5;\endmpfig
%\stopmpfig{5}
%\begin{verbatim}
%    \mpfig
%      draw pic
%        asgroup ""
%        withgroupname "mygroup"
%        withtransparency (1, 1/2) ;
%      draw (left--right) scaled 5 ;
%      draw (up--down) scaled 5 ;
%    \endmpfig
%\end{verbatim}
%\startmpfig
%\noindent\clap{\vrule width 10bp height .25bp depth .25bp}\clap{\vrule width .5bp height 5bp depth 5bp}\usemplibgroup{mygroup}
%\stopmpfig{3}
%\begin{verbatim}
%    \noindent
%    \clap{\vrule width 10bp height .25bp depth .25bp}%
%    \clap{\vrule width .5bp height 5bp depth 5bp}%
%    \usemplibgroup{mygroup}
%\end{verbatim}
%\startmpfig
%\mpfig usemplibgroup "mygroup" withtransparency (1,2/3); draw (left--right) scaled 5; draw (up--down) scaled 5;\endmpfig
%\stopmpfig{4}
%\begin{verbatim}
%    \mpfig
%      usemplibgroup "mygroup"
%        withtransparency (1, 2/3) ;
%      draw (left--right) scaled 5 ;
%      draw (up--down) scaled 5 ;
%    \endmpfig
%\end{verbatim}
%
% Also note that normally the XObjects are not affected by outer color commands.
% However, if you have made the original XObject using |withoutcolor| command,
% colors will have effects on its uncolored objects.
%
% \paragraph{Note on picture shading}
% \hypertarget{para:pictureshading}{When}
% you give shading effect upon a \emph{textual picture} (i.e.\ non-path object)
% inside or outside a transparency group, currently many of the PDF renderers,
% including Mac OS Preview and Foxit Editor, do not interprete PDF coordinates properly.
% If that happens, consider using other PDF viewer such as Adobe Acrobat. An example:
% \mpfig* picture pic[]; pic1 = image(fill fullcircle scaled 60 withoutcolor; fill fullcircle scaled 60 shifted 25right withoutcolor;); pic2 = image(draw pic1 withshadingmethod "linear" withshadingvector (2, 1) withshadingcolors (red, blue)); \endmpfig
%\begin{verbatim}
%    \mpfig*
%      picture pic[];
%      pic1 = image(
%          fill fullcircle scaled 60 withoutcolor;
%          fill fullcircle scaled 60 shifted 25right withoutcolor;
%        ) ;
%      pic2 = image(
%        draw pic1
%          withshadingmethod "linear"
%          withshadingvector (2, 1)
%          withshadingcolors (red, blue)
%      ) ;
%    \endmpfig
%\end{verbatim}
% \startmpfig
% \mpfig draw pic2 asgroup "" withtransparency (1, 2/3); \endmpfig\vskip15pt
% \stopmpfig{3}
%\begin{verbatim}
%    \mpfig                               % shading inside group
%      draw pic2
%        asgroup ""
%        withtransparency (1, 2/3) ;
%    \endmpfig
%\end{verbatim}
% \startmpfig
% \mpfig draw pic1 asgroup "" withshadingmethod "linear" withshadingvector (2, 1) withshadingcolors (red, blue) withtransparency (1, 2/3); \endmpfig
% \stopmpfig{4}
%\begin{verbatim}
%    \mpfig                               % shading outside group
%      draw pic1
%        asgroup ""
%        withshadingmethod "linear"
%        withshadingvector (2, 1)
%        withshadingcolors (red, blue)
%        withtransparency (1, 2/3) ;
%    \endmpfig
%\end{verbatim}
% After some experiment, however, it turned out that
% the best way to get picture shading with transparency group
% is to give shading effect within an ordinary form XObject
% and then wrap it up in a transparency group XObject.
% This sort of double wrapping will be done automatically when you specify `|wrapped|'
% as an optional argument of |asgroup|.
% Most PDF renderers do render it properly:
%\startmpfig
%\mpfig draw pic2 asgroup "wrapped" withtransparency (1, 2/3); \endmpfig
%\stopmpfig{3}
%\begin{verbatim}
%    \mpfig
%      draw pic2
%        asgroup "wrapped"
%        withtransparency (1, 2/3) ;
%    \endmpfig
%\end{verbatim}
% or preferably (see next subsection \secref{mplibgroupendmplibgroup} on \cs{mplibgroup}):
%\startmpfig
%\mplibgroup{myshading}[asgroup="wrapped"]
%\mpfig draw pic2; \endmpfig
%\endmplibgroup
%\mpfig usemplibgroup "myshading" rotated 15 withtransparency (1, 2/3); \endmpfig
%\stopmpfig{7}
%   \hypertarget{doublewrappingexample}{}\relax
%\begin{verbatim}
%    \mplibgroup{myshading}[asgroup="wrapped"]
%      \mpfig
%        draw pic2 ;
%      \endmpfig
%    \endmplibgroup
%
%    \mpfig
%      usemplibgroup "myshading" rotated 15
%        withtransparency (1, 2/3) ;
%    \endmpfig
%\end{verbatim}
%
% \subsubsection[\cs{mplibgroup}]{\cs{mplibgroup\{...\} ...} \cs{endmplibgroup}}
%   \label{sec:mplibgroupendmplibgroup}
% These \TeX\ macros are described here in this subsection, as they are
% deeply related to the |asgroup| operator described just above at \secref{transparencygroup}.
% With these, users can define a transparency group or an ordinary \emph{form XObject}
% from \TeX\ side.
% The syntax is similar to the \cs{mppattern} command described above at \secref{mppattern}.
%
% An example:\footnote{Note that, here again by the option |asgroup="wrapped"|,
%   within a transparency group XObject
%   a tiling pattern is wrapped up in an inner, ordinary XObject.
%   This annoyance is especially for Mac OS Preview which misapplies
%   the transformation matrix to tiling or shading patterns
%   directly wrapped in a transparency group.
%   Most other PDF renderers seem to behave properly even with single wrapping. }
%\startmpfig
%\mplibgroup{texpatt}[asgroup="wrapped",]\mpfig filldraw fullcircle xscaled 100 yscaled 50 withmppattern "pattnocolor" withcolor 2/3red;\endmpfig \endmplibgroup
%\usemplibgroup{texpatt}
%\stopmpfig{10}
%\begin{verbatim}
%    \mplibgroup{texpatt}                  % or \begin{mplibgroup}{texpatt}
%      [                                   % options: see below
%        asgroup="wrapped",
%      ]
%      \mpfig                              % or any other TeX code
%        filldraw fullcircle
%          xscaled 100 yscaled 50
%          withmppattern "pattnocolor"
%          withcolor 2/3 red ;
%      \endmpfig
%    \endmplibgroup                        % or \end{mplibgroup}
%
%    \usemplibgroup{texpatt}
%\end{verbatim}
%\startmpfig
%\mpfig usemplibgroup "texpatt" rotated -15 scaled 1.2 withtransparency(1,2/3); \endmpfig
%\stopmpfig{2}
%\begin{verbatim}
%    \mpfig
%      usemplibgroup "texpatt"
%        rotated -15 scaled 1.2
%        withtransparency (1, 2/3) ;
%    \endmpfig
%\end{verbatim}
%
% Availabe options
% are listed in Table~\ref{tab:mplibgroupoptions}.
% Again, the width/height/depth values of the mplibgroup will be written down into the log file.
%
% \begin{table}
% \centering
% \caption{options for \cs{mplibgroup}}\label{tab:mplibgroupoptions}
% \begin{tabular}{lll}
% \hline
%   Key         & Value Type    & Explanation\\
% \hline
%   |asgroup|   &\emph{string} & \parbox{236bp}{\strut
%                              |""|, or any comma-separated combination of |isolated|,\\[-1pt]
%                              |knockout|, |wrapped| and |off|, or |"masking"|\strut}\\
%  |colorspace| &\emph{string} & \parbox{250bp}{\strut
%                              |/CS| entry to a transparency group, such as |"/DeviceGray"|,\\[-1pt]
%                              |"/DeviceRGB"| or |"/DeviceCMYK"|\strut}\\
%   |bbox|      &\emph{table} or \emph{string} & |llx|, |lly|, |urx|, |ury| values\kern1pt*\\
%   |matrix|    &\emph{table} or \emph{string} & |xx|, |yx|, |xy|, |yy| values\kern1pt*
%                                                or MP transform code\\
%   |resources| &\emph{string}  & PDF resources if needed\\
% \hline
%               &               & \small *\,in string type, numbers are separated by spaces\\
% \end{tabular}
% \end{table}
%
% When |asgroup| option is not given or is given as |"off"|,
% an ordinary form XObject will be generated rather than a transparency group.
% Thus the individual objects, not the XObject as a whole, will be affected
% by outer transparency command, just like the first figure
% in the \hyperlink{noasgroupexample}{example} above at \secref{transparencygroup}.
%
% Option |asgroup="wrapped"| can be regarded as a shortcut of double \cs{mplibgroup} command.
% The content will be wrapped up in an ordinary form XObject
% before being wrapped again in a transparency group.
% This option could be useful when a tiling pattern
% (see the example just above)
% or a picture shading
% (see the \hyperlink{doublewrappingexample}{example} above at \secref{transparencygroup})
% is used in the content.
%
% As for the option |asgroup="masking"|, see the next subsection \secref{withmaskinggroup}.
%
% With |colorspace| option,
% which is no-op for ordinary form XObject,
% users can specify the color space of a transparency group.
% For instance, the mplibgroup will be painted in grayscale model
% when |colorspace=|\allowbreak|"/DeviceGray"| is given to an \emph{isolated} transparency group.\relax
% \footnote{Note that some PDF renderers such as Mac OS Preview or Firefox
%   do not render properly this option.}
%
% As shown, you can reuse the mplibgroup
% using the \TeX\ command \cs{usemplibgroup} or
% the \metapost command |usemplibgroup|.
% The behavior of these commands is the same as that described \hyperlink{usemplibgroup}{above}
% at \secref{transparencygroup},
% excepting that the mplibgroup made by \TeX\ code (not by \metapost code) respects original height and depth.
%
%
% \subsubsection[\ttfamily withmaskinggroup]{\ttfamily ... withmaskinggroup ...}
%   \label{sec:withmaskinggroup}
% Using this command,
% the mplibgroup (see above \secref{mplibgroupendmplibgroup})
% generated by the option \bsx|asgroup=|\allowbreak|"masking"|\esx\ (see Table~\ref{tab:mplibgroupoptions})
% can be utilized as a masking transparency group upon a picture or a path object.
% The syntax is \bsx\meta{picture} \textbar\ \meta{path} |withmaskinggroup| \meta{string}\esx,
% the latter being the name of a pre-defined masking group.
%
% Basically, the masking group should be prepared in \emph{grayscale} color model:
% the area painted with |1| ($\approx$ white: full luminosity) will preserve
% the full color of the object;
% the area painted with |0| ($\approx$ black: zero luminosity) will force
% full transparency, masking it invisibly.\relax
%   \footnote{In fact, colors in other color models are also allowed
%     (such as |white|, |black|, |red|, |green|, |blue|).
%     But they will be converted to grayscale model by the PDF renderer, so that
%     |"/DeviceGray"| is the default value of |colorspace| option to a masking transparency group
%     (see Table~\ref{tab:mplibgroupoptions} at \secref{mplibgroupendmplibgroup}). }
%
% By default, the background color of a masking group is |0| ($\approx$ black),
% which you can change by this macro:
% \begin{description}
% \item[withmaskingbgcolor \meta{color expr}] sets the background color of the masking group.
%   |0| denotes full transparency (masking invisibly); |1|, full color.\relax
%   \footnote{Color expressions in rgb or cmyk model are also allowed,
%     in accordance with the option |colorspace=|\allowbreak|"/DeviceRGB"|
%     or |colorspace=|\allowbreak|"/DeviceCMYK"| given to the masking transparency group.
%     This however we do not recommend as the luminosity is difficult to understand intuitively. }
% \end{description}
% An example:
%\begin{verbatim}
%    \mpfig*
%      picture pic;
%      pic = image(
%          fill fullcircle scaled 80 withcolor blue ;
%          fill fullcircle scaled 80 shifted (25,0) withcolor green ;
%          fill fullcircle scaled 80 shifted (50,0) withcolor red ;
%        );
%    \endmpfig
%
%    \mplibgroup{mymask}[asgroup="masking"]
%      \mpfig
%        label(TEX "\sffamily\bfseries\scshape\Huge Meta" scaled 2, center pic)
%          withcolor 1 ;
%      \endmpfig
%    \endmplibgroup
%\end{verbatim}
%\startmpfig
%\mpfig* picture pic; pic = image(fill fullcircle scaled 80 withcolor blue; fill fullcircle scaled 80 shifted (25,0) withcolor green; fill fullcircle scaled 80 shifted (50,0) withcolor red;);\endmpfig
%\mplibgroup{mymask}[asgroup="masking"]
%\mpfig label(TEX "\sffamily\bfseries\scshape\Huge Meta" scaled 2, center pic) withcolor 1;\endmpfig
%\endmplibgroup
%\mpfig fill bbox pic withshadingmethod "linear" withshadingcolors(red, blue); draw pic withmaskinggroup "mymask" withmaskingbgcolor 1/10 withtransparency (1, 0.8);\endmpfig
%\stopmpfig{1}
%\begin{verbatim}
%    \mpfig
%      fill bbox pic
%        withshadingmethod "linear"
%        withshadingcolors (red, blue) ;
%      draw pic
%        withmaskinggroup "mymask"
%        withmaskingbgcolor 1/10
%        withtransparency (1, 0.8) ;
%    \endmpfig
%\end{verbatim}
%
%
% \subsubsection[\ttfamily mpliblength, mplibuclength]{\ttfamily mpliblength ..., mplibuclength ...}
%   \bsx|mpliblength| \meta{string}\esx\ returns the number of unicode characters in the string.
%   This is a unicode-aware version equivalent to the \metapost primitive |length|, but
%   accepts only a string-type argument.
%   For instance, |mpliblength| |"abçdéf"| returns |6|, not |8|.
%
%   On the other hand,
%   \bsx|mplibuclength| \meta{string}\esx\ returns the number of unicode grapheme clusters in the string.
%   For instance, |mplibuclength| |"Äpfel"|,
%   where |Ä| is encoded using two codepoints (U+0041 and U+0308),
%   returns |5|, not |6| or |7|.
%   This operator requires \pkg{lua-uni-algos} package installed.
%
% \subsubsection[\ttfamily mplibsubstring, mplibucsubstring]{\ttfamily mplibsubstring ... of ..., mplibucsubstring ... of ...}
%   \bsx|mplibsubstring| \meta{pair} |of| \meta{string}\esx\ is a unicode-aware version equivalent to the
%   \metapost's |substring ... of ...| primitive. The syntax is the same as the latter,
%   but the string is indexed by unicode characters.
%   For instance, |mplibsubstring| |(2,5)| |of| |"abçdéf"| returns |"çdé"|,
%   and |mplibsubstring| |(5,2)| |of| |"abçdéf"| returns |"édç"|.
%
%   On the other hand,
%   \bsx|mplibucsubstring| \meta{pair} |of| \meta{string}\esx\ returns the part of the string indexed
%   by unicode grapheme clusters.
%   For instance, |mplibucsubstring| |(0,1)| |of| |"Äpfel"|,
%   where |Ä| is encoded using two codepoints (U+0041 and U+0308),
%   returns |"Ä"|, not |"A"|.
%   This operator requires \pkg{lua-uni-algos} package installed.
%
% \subsection{Lua}
%
% \subsubsection[\ttfamily runscript]{\ttfamily runscript ...}
%   A good many \metapost macros described in this documentation have been implemented
%   using the primitive |runscript|.
%   With \bsx|runscript| \meta{string}\esx, you can run a Lua code chunk from \metapost side
%   and get some \metapost code returned by Lua if you want.
%   As the functionality is provided by the \mplib library itself,
%   \pkg{luamplib} does not have much to say about it.
%
%   One thing is worth mentioning, however:
%   if you return a Lua \emph{table} to the \metapost process,
%   it is automatically converted to a relevant \metapost data type
%   such as pair, color, cmykcolor or transform.
%   So users can save some extra toil of converting a table to a string, though it's not a big deal.
%   For instance, |runscript| |"return {1,0,0}"| will give you the \metapost color expression |(1,0,0)|
%   automatically.
%
% \subsubsection[\ttfamily luamplib.instances]{Lua table \ttfamily luamplib.instances}
%   \label{sec:luamplibinstances}
%   Users can access the Lua table containing \mplib instances, |luamplib.instances|,
%   through which \metapost variables are also easily accessible from Lua side,
%   as documented in Lua\TeX{} manual \S\,11.2.8.4 (|texdoc luatex|).
%   The following example will print |false|, |3.0|, |MetaPost| and
%   the knots and the cyclicity of the path |unitsquare|.
%\begin{verbatim}
%    \begin{mplibcode}[myinstance]
%      boolean b; b = 1 > 2;
%      numeric n; n = 3;
%      string s;  s = "MetaPost";
%      path p;    p = unitsquare;
%    \end{mplibcode}
%
%    \directlua{
%      local myinstance = luamplib.instances.myinstance
%      print( myinstance:get_boolean "b" )
%      print( myinstance:get_numeric "n" )
%      print( myinstance:get_string  "s" )
%      local t = myinstance:get_path "p"
%      for k,v in pairs(t) do
%        print(k, type(v)=='table' and table.concat(v,' ') or v)
%      end
%    }
%\end{verbatim}
%   Of course, this sort of Lua code can also be run inside \metapost code using |runscript|
%   command.
%   Again, of course you can access a \metapost variable using your own \TeX\ macro. For example:
%\startmpfig
%\mpfig* numeric n; n = 3;\endmpfig
%\def\mpnumeric#1#2{\directlua{tex.sprint(tostring(luamplib.instances["#1"]:get_numeric"#2"))}}
%\mpnumeric{@mpfig}{n}\relax
%\stopmpfig{4}
%\begin{verbatim}
%    \def\mpnumeric#1#2{\directlua{
%      tex.sprint(tostring(luamplib.instances["#1"]:get_numeric"#2"))
%    }}
%    \mpnumeric{myinstance}{n}\relax
%\end{verbatim}
%
% \subsubsection[\ttfamily luamplib.process\_mplibcode]{Lua function \ttfamily luamplib.process\_mplibcode}
%   Users can run a \metapost code chunk from Lua side by using this function:
%\begin{verbatim}
%    luamplib.process_mplibcode (<string> metapost code, <string> instance name)
%\end{verbatim}
%
%   The second argument cannot be absent, but can be an empty string (|""|) which
%   means that it has no instance name.
%
%   Some other elements in the |luamplib| namespace, listed in Table~\ref{tab:elementsinluamplib},
%   can affect the process of |process_mplibcode|.
%
%   \begin{table}
%     \centering
%     \caption{elements in \texttt{luamplib} table (partial)}\label{tab:elementsinluamplib}
%   \begin{tabular}{llll}\hline
%     Key & Type & Related \TeX\ macro & Cf. \\\hline
%     |codeinherit|	& \emph{boolean} & \cs{mplibcodeinherit} & \secref{mplibcodeinherit}\\
%     |everyendmplib|	& \emph{table} & \cs{everyendmplib} & \secref{everymplib}\\
%     |everymplib| & \emph{table} & \cs{everymplib} & \secref{everymplib}\\
%     |getcachedir|	& \emph{function} \parg{string} & \cs{mplibcachedir} & \secref{mplibcachedir}\\
%     |globaltextext|	& \emph{boolean} & \cs{mplibglobaltextext} & \secref{mplibglobaltextext}\\
%     |legacyverbatimtex| & \emph{boolean} & \cs{mpliblegacybehavior} & \secref{mpliblegacybehavior}\\
%     |noneedtoreplace|	& \emph{table} & \cs{mplibmakenocache} & \secref{mplibcachedir}\\
%     |numbersystem|	& \emph{string} & \cs{mplibnumbersystem} & \secref{mplibnumbersystem}\\
%     |setformat|	& \emph{function} \parg{string} & \cs{mplibsetformat} & \secref{mplibsetformat}\\
%     |showlog|	& \emph{boolean} & \cs{mplibshowlog} & \secref{mplibshowlog}\\
%     |textextlabel| & \emph{boolean} & \cs{mplibtextextlabel} & \secref{mplibtextextlabel}\\
%     |verbatiminput| & \emph{boolean} & \cs{mplibverbatim} & \secref{mplibverbatim}\\\hline
%   \end{tabular}
%   \end{table}
%
% \subsubsection[\ttfamily luamplib.registerpattern]{Lua function \ttfamily luamplib.registerpattern}
%   This is the Lua interface for \cs{mppattern} |...| \cs{endmppattern}
%   described above at \secref{mppattern}.
%\begin{verbatim}
%    luamplib.registerpattern (<number> box register, <string> pattern name, <table> options)
%\end{verbatim}
%
%   The first argument is the register of a box containing a pattern cell,
%   which should be prepared in advance by the user. For instance,
%   \cs{setbox0=}\allowbreak\cs{hbox}\allowbreak|{\tiny\TeX}|,
%   or corresponding Lua code using |tex.setbox| function; then the argument should be |0|.\relax
%     \footnote{In DVI mode, \TeX\ macro `|mplibpatternname|' should be set as \meta{pattern name}
%     before preparing the box, if shading pattern (i.e.\ shading on picture) is used
%     in the pattern cell. }
%
%   As for the third argument, see above Table~\ref{tab:mppatternoptions}.
%   The argument cannot be absent, but can be an empty table, i.e.\ |{ }|.
%
% \subsubsection[\ttfamily luamplib.registergroup]{Lua function \ttfamily luamplib.registergroup}
%   This is the Lua interface for \cs{mplibgroup} |...| \cs{endmplibgroup}
%   described above at \secref{mplibgroupendmplibgroup}.
%\begin{verbatim}
%    luamplib.registergroup (<number> box register, <string> group name, <table> options)
%\end{verbatim}
%
%   The first argument is the register of a box prepared in advance by the user.
%   When the contents of the box have been generated from \TeX\ (not \metapost) code,
%   please make sure that both of the \TeX\ macros `|MPllx|' and `|MPlly|' are defined as `|0|'
%   before invoking the Lua function.\footnote{\relax
%     In DVI mode, \TeX\ macro `|mplibgroupname|' also should be set as \meta{group name} before
%     preparing the box, if shading pattern (i.e.\ shading on picture) is used in the mplibgroup. }
%
%   As for the third argument, see above Table~\ref{tab:mplibgroupoptions}.
%   The argument cannot be absent, but can be an empty table, i.e.\ |{ }|.
%
%   Reusing an mplibgroup, \cs{usemplibgroup}\marg{name}, is basically the same as
%   running the \TeX\ macro `|luamplib.group.|\meta{name}'.
%   If you need the boxresource index,
%   inspect this macro using |token.get_macro| function.
%
%
%    \section{Implementation}
%
%    \subsection{Lua module}
%
% \iffalse
%<*lua>
% \fi
%
%    \begin{macrocode}

luatexbase.provides_module {
  name          = "luamplib",
  version       = "2.41.3",
  date          = "2026/05/26",
  description   = "Lua package to typeset Metapost with LuaTeX's MPLib.",
}

%    \end{macrocode}
%
%    Use the |luamplib| namespace, since |mplib| is for the \metapost library
%    itself. \ConTeXt{} uses |metapost|.
%    \begin{macrocode}
luamplib          = luamplib or { }
local luamplib    = luamplib

local format, abs = string.format, math.abs

%    \end{macrocode}
%
%    Use our own function for warn/info/err.
%    \begin{macrocode}
local function termorlog (target, text, kind)
  if text then
    local mod, write, append = "luamplib", texio.write_nl, texio.write
    kind = kind
        or target == "term" and "Warning (more info in the log)"
        or target == "log" and "Info"
        or target == "term and log" and "Warning"
        or "Error"
    target = kind == "Error" and "term and log" or target
    local t = text:explode"\n+"
    write(target, format("Module %s %s:", mod, kind))
    if #t == 1 then
      append(target, format(" %s", t[1]))
    else
      for _,line in ipairs(t) do
        write(target, line)
      end
      write(target, format("(%s)     ", mod))
    end
    append(target, format(" on input line %s", tex.inputlineno))
    write(target, "")
    if kind == "Error" then error() end
  end
end
local function warn (...) -- beware '%' symbol
  termorlog("term and log", select("#",...) > 1 and format(...) or ...)
end
local function info (...)
  termorlog("log", select("#",...) > 1 and format(...) or ...)
end
local function err (...)
  termorlog("error", select("#",...) > 1 and format(...) or ...)
end

luamplib.showlog  = luamplib.showlog or false

%    \end{macrocode}
%
%   Provide a few ``shortcuts'' expected by the code.
%    \begin{macrocode}
local tableconcat = table.concat
local tableinsert = table.insert
local tableunpack = table.unpack
local texsprint   = tex.sprint
local texgettoks  = tex.gettoks
local texgetbox   = tex.getbox
local texruntoks  = tex.runtoks
if not texruntoks then
  err("Your LuaTeX version is too old. Please upgrade it to the latest")
end
local is_defined  = token.is_defined
local get_macro   = token.get_macro
local mplib = require ('mplib')
local kpse  = require ('kpse')
local lfs   = require ('lfs')
local lfsattributes = lfs.attributes
local lfsisdir      = lfs.isdir
local lfsmkdir      = lfs.mkdir
local lfstouch      = lfs.touch
local ioopen        = io.open

%    \end{macrocode}
%
%    Some helper functions, prepared for the case when |l-file| etc
%    is not loaded.
%    \begin{macrocode}
local file = file or { }
local replacesuffix = file.replacesuffix or function(filename, suffix)
  return (filename:gsub("%.[%a%d]+$","")) .. "." .. suffix
end
local is_writable = file.is_writable or function(name)
  if lfsisdir(name) then
    name = name .. "/_luam_plib_temp_file_"
    local fh = ioopen(name,"w")
    if fh then
      fh:close(); os.remove(name)
      return true
    end
  end
end
local mk_full_path = lfs.mkdirp or lfs.mkdirs or function(path)
  local full = ""
  for sub in path:gmatch("(/*[^\\/]+)") do
    full = full .. sub
    lfsmkdir(full)
  end
end

%    \end{macrocode}
%
%    |btex| |...| |etex| in input |.mp| files will be replaced in finder.
%    Because of the limitation of \mplib regarding |make_text|,
%    we might have to make cache files modified from input files.
%
%     First of all, determine the directory to store cache files.
%    \begin{macrocode}
local cachedir
local function outputdir ()
  if lfstouch then
    for i,v in ipairs{'TEXMFVAR','TEXMF_OUTPUT_DIRECTORY','.','TEXMFOUTPUT'} do
      local var = i == 3 and v or kpse.var_value(v)
      if var and var ~= "" then
        for _,vv in ipairs(var:explode(os.type == "unix" and ":" or ";")) do
          local dir = format("%s/%s",vv,"luamplib_cache")
          if not lfsisdir(dir) then
            mk_full_path(dir)
          end
          if is_writable(dir) then
            cachedir = dir; return cachedir
          end
        end
      end
    end
  end
  cachedir = "."; return cachedir
end
function luamplib.getcachedir(dir)
  dir = dir:gsub("##","#")
  dir = dir:gsub("^~",
    os.type == "windows" and os.getenv("UserProfile") or os.getenv("HOME"))
  if lfstouch and dir then
    if lfsisdir(dir) then
      if is_writable(dir) then
        cachedir = dir
      else
        warn("Directory '%s' is not writable!", dir)
      end
    else
      warn("Directory '%s' does not exist!", dir)
    end
  end
end
%    \end{macrocode}
%    Some basic \metapost files not necessary to make cache files.
%    \begin{macrocode}
local noneedtoreplace = {
  ["boxes.mp"] = true, --  ["format.mp"] = true,
  ["graph.mp"] = true, ["marith.mp"] = true, ["mfplain.mp"] = true,
  ["mpost.mp"] = true, ["plain.mp"] = true, ["rboxes.mp"] = true,
  ["sarith.mp"] = true, ["string.mp"] = true, -- ["TEX.mp"] = true,
  ["metafun.mp"] = true, ["metafun.mpiv"] = true, ["mp-abck.mpiv"] = true,
  ["mp-apos.mpiv"] = true, ["mp-asnc.mpiv"] = true, ["mp-bare.mpiv"] = true,
  ["mp-base.mpiv"] = true, ["mp-blob.mpiv"] = true, ["mp-butt.mpiv"] = true,
  ["mp-char.mpiv"] = true, ["mp-chem.mpiv"] = true, ["mp-core.mpiv"] = true,
  ["mp-crop.mpiv"] = true, ["mp-figs.mpiv"] = true, ["mp-form.mpiv"] = true,
  ["mp-func.mpiv"] = true, ["mp-grap.mpiv"] = true, ["mp-grid.mpiv"] = true,
  ["mp-grph.mpiv"] = true, ["mp-idea.mpiv"] = true, ["mp-luas.mpiv"] = true,
  ["mp-mlib.mpiv"] = true, ["mp-node.mpiv"] = true, ["mp-page.mpiv"] = true,
  ["mp-shap.mpiv"] = true, ["mp-step.mpiv"] = true, ["mp-text.mpiv"] = true,
  ["mp-tool.mpiv"] = true, ["mp-cont.mpiv"] = true,
}
luamplib.noneedtoreplace = noneedtoreplace

%    \end{macrocode}
%    Pattern formats to replace |btex| and |verbatimtex| |...| |etex| in input files,
%    if needed.
%    \begin{macrocode}
local name_b = "%f[%a_]"
local name_e = "%f[^%a_]"
local btex_etex = name_b.."btex"..name_e.."%s*(.-)%s*"..name_b.."etex"..name_e
local verbatimtex_etex = name_b.."verbatimtex"..name_e.."%s*(.-)%s*"..name_b.."etex"..name_e

%    \end{macrocode}
%   Function |luamplib.finder|
%    \begin{macrocode}
local currenttime = os.time()
do
  local luamplibtime = lfsattributes(kpse.find_file"luamplib.lua", "modification")
%    \end{macrocode}
%    |format.mp| is much complicated, so specially treated.
%    \begin{macrocode}
  local function replaceformatmp(file,newfile,ofmodify)
    local fh = ioopen(file,"r")
    if not fh then return file end
    local data = fh:read("*all"); fh:close()
    fh = ioopen(newfile,"w")
    if not fh then return file end
    fh:write(
      "let normalinfont = infont;\n",
      "primarydef str infont name = rawtextext(str) enddef;\n",
      data,
      "vardef Fmant_(expr x) = rawtextext(decimal abs x) enddef;\n",
      "vardef Fexp_(expr x) = rawtextext(\"$^{\"&decimal x&\"}$\") enddef;\n",
      "let infont = normalinfont;\n"
    ); fh:close()
    lfstouch(newfile,currenttime,ofmodify)
    return newfile
  end
  local function replaceinputmpfile (name,file)
    local ofmodify = lfsattributes(file,"modification")
    if not ofmodify then return file end
    local newfile = name:gsub("%W","_")
    newfile = format("%s/luamplib_input_%s", cachedir or outputdir(), newfile)
    if newfile and luamplibtime then
      local nf = lfsattributes(newfile)
      if nf and nf.mode == "file" and
        ofmodify == nf.modification and luamplibtime < nf.access then
        return nf.size == 0 and file or newfile
      end
    end
    if name == "format.mp" then return replaceformatmp(file,newfile,ofmodify) end
    local fh = ioopen(file,"r")
    if not fh then return file end
    local data = fh:read("*all"); fh:close()
%    \end{macrocode}
%    ``|etex|'' must be preceded by a space and followed by a space or semicolon as specified in
%    \LuaTeX\ manual, which is not the case of standalone \metapost though.
%    \begin{macrocode}
    local count,cnt = 0,0
    data, cnt = data:gsub(btex_etex, "btex %1 etex ") -- space
    count = count + cnt
    data, cnt = data:gsub(verbatimtex_etex, "verbatimtex %1 etex;") -- semicolon
    count = count + cnt
    if count == 0 then
      noneedtoreplace[name] = true
      fh = ioopen(newfile,"w");
      if fh then
        fh:close()
        lfstouch(newfile,currenttime,ofmodify)
      end
      return file
    end
    fh = ioopen(newfile,"w")
    if not fh then return file end
    fh:write(data); fh:close()
    lfstouch(newfile,currenttime,ofmodify)
    return newfile
  end
%    \end{macrocode}
%    As the finder function for \mplib, use the |kpse| library and
%    make it behave like as if \metapost was used. And replace |.mp| files with
%    cache files if needed.
%    See also \#74, \#97.
%    \begin{macrocode}
  local mpkpse
  do
    local exe = 0
    while arg[exe-1] do
      exe = exe-1
    end
    mpkpse = kpse.new(arg[exe], "mpost")
  end
  local special_ftype = {
    pfb = "type1 fonts",
    enc = "enc files",
  }
  function luamplib.finder (name, mode, ftype)
    if mode == "w" then
      if name and name ~= "mpout.log" then
        kpse.record_output_file(name) -- recorder
      end
      return name
    else
      ftype = special_ftype[ftype] or ftype
      local file = mpkpse:find_file(name,ftype)
      if file then
        if lfstouch and ftype == "mp" and not noneedtoreplace[name] and not noneedtoreplace["*.mp"] then
          file = replaceinputmpfile(name,file)
        end
      else
        file = mpkpse:find_file(name, name:match("%a+$"))
      end
      if file then
        kpse.record_input_file(file) -- recorder
      end
      return file
    end
  end
end

%    \end{macrocode}
%
%    For the main function: |process|
%
%    \emph{plain} or \emph{metafun},
%    though we cannot support \emph{metafun} format fully.
%    \begin{macrocode}
local currentformat = "plain"
function luamplib.setformat (name)
  currentformat = name
end
%    \end{macrocode}
%    v2.9 has introduced the concept of ``code inherit''
%    \begin{macrocode}
luamplib.codeinherit = false
local mplibinstances = {}
luamplib.instances = mplibinstances
local has_instancename = false

local process
do
  local function reporterror (result, prevlog)
    if not result then
      err("no result object returned")
    else
      local t, e, l = result.term, result.error, result.log
%    \end{macrocode}
%    log has more information than term, so log first (2021/08/02)
%    \begin{macrocode}
      local log = l or t or "no-term"
      log = log:gsub("%(Please type a command or say `end'%)",""):gsub("\n+","\n")
      if result.status > 0 then
        local first = log:match"(.-\n! .-)\n! "
        if first then
          termorlog("term", first)
          termorlog("log", log, "Warning")
        else
          warn(log)
        end
        if result.status > 1 then
          err(e or "see above messages")
        end
      elseif prevlog then
        log = prevlog..log
%    \end{macrocode}
%    v2.6.1: now luamplib does not disregard |show| command,
%    even when |luamplib.showlog| is false.  Incidentally,
%    it does not raise error nor prints an info,
%    even if output has no figure.
%    \begin{macrocode}
        local show = log:match"\n>>? .+"
        if show then
          termorlog("term", show, "Info (more info in the log)")
          info(log)
        elseif luamplib.showlog and log:find"%g" then
          info(log)
        end
      end
      return log
    end
  end
%    \end{macrocode}
%     |lualibs-os.lua| installs a randomseed. When this file is not loaded,
%     we should explicitly seed a unique integer to get random randomseed for each run.
%    \begin{macrocode}
  if not math.initialseed then math.randomseed(currenttime) end
  local function luamplibload (name)
    local mpx = mplib.new {
      ini_version = true,
      find_file   = luamplib.finder,
%    \end{macrocode}
%    Make use of |make_text| and |run_script|. And we provide |numbersystem| option since v2.4.
%    See \url{https://github.com/lualatex/luamplib/issues/21}.
%    \begin{macrocode}
      make_text   = luamplib.maketext,
      run_script  = luamplib.runscript,
      math_mode   = luamplib.numbersystem,
      job_name    = tex.jobname,
      random_seed = math.random(4095),
      utf8_mode   = true,
      extensions  = 1,
    }
%    \end{macrocode}
%    Append our own \metapost preamble to the preamble loading plain/metafun format.
%    \begin{macrocode}
    local preamble = tableconcat{
      format(luamplib.preambles.preamble, replacesuffix(name,"mp")),
      luamplib.preambles.mplibcode,
      luamplib.legacyverbatimtex and luamplib.preambles.legacyverbatimtex or "",
      luamplib.textextlabel and luamplib.preambles.textextlabel or "",
    }
    local result, log
    if not mpx then
      result = { status = 99, error = "out of memory"}
    else
      result = mpx:execute(preamble)
    end
    log = reporterror(result)
    return mpx, result, log
  end
%    \end{macrocode}
%    Here, excute each |mplibcode| data,
%    ie |\begin{mplibcode} ... \end{mplibcode}|.
%    \begin{macrocode}
  local process_stack = 0
  function process (data, instancename)
    local currfmt
    process_stack = process_stack + 1
    if instancename and instancename ~= "" then
      currfmt = instancename
      has_instancename = true
    else
      currfmt = tableconcat{
        currentformat,
        luamplib.numbersystem or "scaled",
        tostring(luamplib.textextlabel),
        tostring(luamplib.legacyverbatimtex),
        tostring(process_stack), -- try to address #63
      }
      has_instancename = false
    end
    local mpx = mplibinstances[currfmt]
    local standalone = not (has_instancename or luamplib.codeinherit)
    if mpx and standalone then
      mpx:finish()
    end
    local log = ""
    if standalone or not mpx then
      mpx, _, log = luamplibload(currentformat)
      mplibinstances[currfmt] = mpx
    end
    local converted, result = false, {}
    if mpx and data then
      result = mpx:execute(data)
      local log = reporterror(result, log)
      if log then
        if result.fig then
          converted = luamplib.convert(result)
        end
      end
    else
      err"Mem file unloadable. Maybe generated with a different version of mplib?"
    end
    process_stack = process_stack - 1
    return converted, result
  end
end

%    \end{macrocode}
%
%    |dvipdfmx| is supported, though nobody seems to use it.
%    \begin{macrocode}
local pdfmode = tex.outputmode > 0

%    \end{macrocode}
%
%    |make_text| and some |run_script| uses \LuaTeX's |tex.runtoks|.
%    \begin{macrocode}
local catlatex = luatexbase.registernumber("catcodetable@latex")
local catat11  = luatexbase.registernumber("catcodetable@atletter")
%    \end{macrocode}
%    |tex.scantoks| sometimes fail to read catcode properly, especially
%    |\#|, |\&|, or |\%|. After some experiment, we dropped using it.
%    Instead, a function containing |tex.sprint| seems to work nicely.
%    \begin{macrocode}
local function run_tex_code (str, cat)
  texruntoks(function() texsprint(cat or catlatex, str) end)
end
%    \end{macrocode}
%    For conversion of |sp| to |bp|.
%    \begin{macrocode}
local factor = 65536*(7227/7200)

%    \end{macrocode}
%
%    Prepare textext box number containers, locals and globals.
%    |localid| can be any number. They are local anyway.
%    The number will be reset at the start of a new code chunk.
%    Global boxes will use |\newbox| command in |tex.runtoks| process.
%    This is the same when |codeinherit| is true.
%    Boxes in instances with name will also be global, so that
%    their tex boxes can be shared among instances of the same name.
%    \begin{macrocode}
local texboxes = { globalid = 0, localid = 4096 }
local process_tex_text
do
  local textext_fmt = 'image(addto currentpicture doublepath unitsquare \z
    xscaled %f yscaled %f shifted (0,-%f) \z
    withprescript "mplibtexboxid=%i:%f:%f")'
  function process_tex_text (str, maketext)
    if str then
      if not maketext then str = str:gsub("\r.-$","") end
      local global = (has_instancename or luamplib.globaltextext or luamplib.codeinherit)
                     and "\\global" or ""
      local tex_box_id
      if global == "" then
        tex_box_id = texboxes.localid + 1
        texboxes.localid = tex_box_id
      else
        local boxid = texboxes.globalid + 1
        texboxes.globalid = boxid
        run_tex_code(format([[\expandafter\newbox\csname luamplib.box.%s\endcsname]], boxid))
        tex_box_id = tex.getcount'allocationnumber'
      end
      if str:find"^%[taggingoff%]" then
        str = str:gsub("^%[taggingoff%]%s*","")
        run_tex_code(format("\\luamplibnotagtextboxset{%i}{%s\\setbox%i\\hbox{%s}}",
                            tex_box_id, global, tex_box_id, str))
      else
        run_tex_code(format("\\luamplibtagtextboxset{%i}{%s\\setbox%i\\hbox{%s}}",
                            tex_box_id, global, tex_box_id, str))
      end
      local box = texgetbox(tex_box_id)
      local wd  = box.width  / factor
      local ht  = box.height / factor
      local dp  = box.depth  / factor
      return textext_fmt:format(wd, ht+dp, dp, tex_box_id, wd, ht+dp)
    end
    return ""
  end
end

%    \end{macrocode}
%
%    Make |color| or |xcolor|'s color expressions usable,
%    with \cs{mpcolor} or |mplibcolor|. These commands should be used
%    with graphical objects.
%    Attempt to support l3color as well.
%    \begin{macrocode}
if is_defined'color_select:n' then
  run_tex_code{
    "\\newcatcodetable\\luamplibcctabexplat",
    "\\begingroup",
    "\\catcode`@=11 ",
    "\\catcode`_=11 ",
    "\\catcode`:=11 ",
    "\\savecatcodetable\\luamplibcctabexplat",
    "\\endgroup",
  }
end
local ccexplat = luatexbase.registernumber"luamplibcctabexplat"

local process_color, process_mplibcolor
%    \end{macrocode}
% A common function for color functions
%    \begin{macrocode}
local function colorsplit (res)
  local t, tt = { }, res:gsub("[%[%]]","",2):explode()
  local be = tt[1]:find"^%d" and 1 or 2
  for i=be, #tt do
    if not tonumber(tt[i]) then break end
    t[#t+1] = tt[i]
  end
  if #t == 0 then -- named color in DVI mode with no DocumentMetadata
    run_tex_code{"\\extractcolorspecs{", tt[3], "}\\mplibtmpa\\mplibtmpb"}
    t = get_macro"mplibtmpb":explode","
  end
  return t
end
do
  local colfmt = ccexplat and "l3color" or "xcolor"
  local mplibcolorfmt = {
    xcolor = tableconcat{
      [[\begingroup\let\XC@mcolor\relax]],
      [[\def\set@color{\global\mplibtmptoks\expandafter{\current@color}}]],
      [[\color%s\endgroup]],
    },
    l3color = tableconcat{
      [[\begingroup\def\__color_select:N#1{\expandafter\__color_select:nn#1}]],
      [[\def\__color_backend_select:nn#1#2{\global\mplibtmptoks{#1 #2}}]],
      [[\def\__kernel_backend_literal:e#1{\global\mplibtmptoks\expandafter{\expanded{#1}}}]],
      [[\color_select:n%s\endgroup]],
    },
  }
  function process_color (str)
    if str then
      if not str:find("%b{}") then
        str = format("{%s}",str)
      end
      local myfmt = mplibcolorfmt[colfmt]
      if colfmt == "l3color" and is_defined"color" then
        if str:find("%b[]") then
          myfmt = mplibcolorfmt.xcolor
        else
          for _,v in ipairs(str:match"{(.+)}":explode"!") do
            if not v:find("^%s*%d+%s*$") then
              local pp = get_macro(format("l__color_named_%s_prop",v))
              if not pp or pp == "" then
                myfmt = mplibcolorfmt.xcolor
                break
              end
            end
          end
        end
      end
      run_tex_code(myfmt:format(str), ccexplat or catat11)
      local t = texgettoks"mplibtmptoks"
      if not pdfmode then
        if t:find"^hsb" or not t:find"%d" then
          t = "color push " .. t
        elseif not t:find"^pdf" then
          t = t:gsub("%a+ (.+)","pdf:bc [%1]")
        end
      end
      return format('1 withprescript "mpliboverridecolor=%s"', t)
    end
    return ""
  end
  function process_mplibcolor(str)
    local res = process_color(str)
    if res:find" cs " or res:find"@pdf.obj" or res:find"color push" then return res end
    res = colorsplit(res:match'"mpliboverridecolor=(.+)"')
    return format("(%s)", tableconcat(res, ","))
  end
end

%    \end{macrocode}
%
%    for \cs{mpdim} or |mplibdimen|
%    \begin{macrocode}
local function process_dimen (str)
  if str then
    str = str:gsub("{(.+)}","%1")
    run_tex_code(format([[\mplibtmptoks\expandafter{\the\dimexpr %s\relax}]], str))
    return format("begingroup %s endgroup", texgettoks"mplibtmptoks")
  end
  return ""
end

%    \end{macrocode}
%
%    Newly introduced method of processing |verbatimtex| |...| |etex|.
%    This function is used when |\mpliblegacybehavior{false}| is declared.
%    \begin{macrocode}
local function process_verbatimtex_text (str)
  if str then
    run_tex_code(str)
  end
  return ""
end

%    \end{macrocode}
%
%    For legacy verbatimtex process.
%    |verbatimtex| |...| |etex| before |beginfig()|
%    is inserted just before the \mplib box. And
%    \TeX\ code inside |beginfig() ... endfig| is inserted after the \mplib box.
%    \begin{macrocode}
local tex_code_pre_mplib = {}
luamplib.figid = 1
luamplib.in_the_fig = false
local function process_verbatimtex_prefig (str)
  if str then
    tex_code_pre_mplib[luamplib.figid] = str
  end
  return ""
end
local function process_verbatimtex_infig (str)
  if str then
    return format('special "postmplibverbtex=%s";', str)
  end
  return ""
end

%    \end{macrocode}
%
%    For \emph{metafun} format. see issue \#79.
%    \begin{macrocode}
mp = mp or {}
local mp = mp
mp.mf_path_reset = mp.mf_path_reset or function() end
mp.mf_finish_saving_data = mp.mf_finish_saving_data or function() end
mp.report = mp.report or info
%    \end{macrocode}
%    \emph{metafun} 2021-03-09 changes crashes luamplib.
%    \begin{macrocode}
catcodes = catcodes or {}
local catcodes = catcodes
catcodes.numbers = catcodes.numbers or {}
catcodes.numbers.ctxcatcodes = catcodes.numbers.ctxcatcodes or catlatex
catcodes.numbers.texcatcodes = catcodes.numbers.texcatcodes or catlatex
catcodes.numbers.luacatcodes = catcodes.numbers.luacatcodes or catlatex
catcodes.numbers.notcatcodes = catcodes.numbers.notcatcodes or catlatex
catcodes.numbers.vrbcatcodes = catcodes.numbers.vrbcatcodes or catlatex
catcodes.numbers.prtcatcodes = catcodes.numbers.prtcatcodes or catlatex
catcodes.numbers.txtcatcodes = catcodes.numbers.txtcatcodes or catlatex

%    \end{macrocode}
%
%    Now |luamplib.runscript|
%    \begin{macrocode}
do
  local runscript_funcs = {
    luamplibtext    = process_tex_text,
    luamplibcolor   = process_mplibcolor,
    luamplibdimen   = process_dimen,
    luamplibprefig  = process_verbatimtex_prefig,
    luamplibinfig   = process_verbatimtex_infig,
    luamplibverbtex = process_verbatimtex_text,
  }
%    \end{macrocode}
%    A function from \ConTeXt\ general.
%    \begin{macrocode}
  local function mpprint(buffer,...)
    for i=1,select("#",...) do
      local value = select(i,...)
      if value ~= nil then
        local t = type(value)
        if t == "number" then
          buffer[#buffer+1] = format("%.16f",value)
        elseif t == "string" then
          buffer[#buffer+1] = value
        elseif t == "table" then
          buffer[#buffer+1] = "(" .. tableconcat(value,",") .. ")"
        else -- boolean or whatever
          buffer[#buffer+1] = tostring(value)
        end
      end
    end
  end
  function luamplib.runscript (code)
    local id, str = code:match("(.-){(.*)}")
    if id and str then
      local f = runscript_funcs[id]
      if f then
        local t = f(str)
        if t then return t end
      end
    end
    local f = loadstring(code)
    if type(f) == "function" then
      local buffer = {}
      function mp.print(...)
        mpprint(buffer,...)
      end
      local res = {f()}
      buffer = tableconcat(buffer)
      if buffer and buffer ~= "" then
        return buffer
      end
      buffer = {}
      mpprint(buffer, tableunpack(res))
      return tableconcat(buffer)
    end
    return ""
  end
end

%    \end{macrocode}
%
%    |luamplib.maketext|
%    \begin{macrocode}
luamplib.legacyverbatimtex = true
do
%    \end{macrocode}
%    |make_text| must be one liner, so comment sign is not allowed.
%    \begin{macrocode}
  local function protecttexcontents (str)
    return str:gsub("\\%%", "\0PerCent\0")
              :gsub("%%.-\n", "")
              :gsub("%%.-$",  "")
              :gsub("%zPerCent%z", "\\%%")
              :gsub("\r.-$",  "")
              :gsub("%s+", " ")
  end
  function luamplib.maketext (str, what)
    if str and str ~= "" then
      str = protecttexcontents(str)
      if what == 1 then
        if not str:find("\\documentclass"..name_e) and
           not str:find("\\begin%s*{document}") and
           not str:find("\\documentstyle"..name_e) and
           not str:find("\\usepackage"..name_e) then
          if luamplib.legacyverbatimtex then
            if luamplib.in_the_fig then
              return process_verbatimtex_infig(str)
            else
              return process_verbatimtex_prefig(str)
            end
          else
            return process_verbatimtex_text(str)
          end
        end
      else
        return process_tex_text(str, true) -- bool is for 'char13'
      end
    end
    return ""
  end
end

%    \end{macrocode}
%
%    luamplib's \metapost color operators
%    \begin{macrocode}
luamplib.gettexcolor = function (str, rgb)
  local res = process_color(str):match'"mpliboverridecolor=(.+)"'
  if res:find" cs " or res:find"@pdf.obj" then
    if not rgb then
      warn("%s is a spot color. Forced to CMYK", str)
    end
    run_tex_code({
      "\\color_export:nnN{",
      str,
      "}{",
      rgb and "space-sep-rgb" or "space-sep-cmyk",
      "}\\mplib_@tempa",
    },ccexplat)
    return get_macro"mplib_@tempa":explode()
  end
  local t = colorsplit(res)
  if #t == 3 or not rgb then return t end
  if #t == 4 then
    return { 1 - math.min(1,t[1]+t[4]), 1 - math.min(1,t[2]+t[4]), 1 - math.min(1,t[3]+t[4]) }
  end
  return { t[1], t[1], t[1] }
end

luamplib.shadecolor = function (str)
  local res = process_color(str):match'"mpliboverridecolor=(.+)"'
  if res:find" cs " or res:find"@pdf.obj" then -- spot color shade: l3 only
%    \end{macrocode}
%   An example of spot color shading:
%\begin{verbatim}
%    \DocumentMetadata{ }
%    \documentclass{article}
%    \usepackage{luamplib}
%    \ExplSyntaxOn
%    \color_model_new:nnn { pantone3005 }
%      { Separation }
%      {
%        name = PANTONE~3005~U ,
%        alternative-model = cmyk ,
%        alternative-values = {1, 0.56, 0, 0}
%      }
%      \color_set:nnn{spotA}{pantone3005}{1}
%      \color_set:nnn{spotB}{pantone3005}{0.6}
%    \color_model_new:nnn { pantone1215 }
%      { Separation }
%      {
%        name = PANTONE~1215~U ,
%        alternative-model = cmyk ,
%        alternative-values = {0, 0.15, 0.51, 0}
%      }
%      \color_set:nnn{spotC}{pantone1215}{1}
%    \color_model_new:nnn { pantone2040 }
%      { Separation }
%      {
%        name = PANTONE~2040~U ,
%        alternative-model = cmyk ,
%        alternative-values = {0, 0.28, 0.21, 0.04}
%      }
%      \color_set:nnn{spotD}{pantone2040}{1}
%    \ExplSyntaxOff
%    \begin{document}
%    \begin{mplibcode}
%    beginfig(1)
%      fill unitsquare xscaled \mpdim\textwidth yscaled 1cm
%        withshadingmethod "linear"
%        withshadingvector (0,1)
%        withshadingstep (
%          withshadingfraction .5
%          withshadingcolors ("spotB","spotC")
%        )
%        withshadingstep (
%          withshadingfraction 1
%          withshadingcolors ("spotC","spotD")
%        )
%        ;
%    endfig;
%    \end{mplibcode}
%    \end{document}
%\end{verbatim}
%   another one: user-defined DeviceN colorspace
%\begin{verbatim}
%    \DocumentMetadata{ }
%    \documentclass{article}
%    \usepackage{luamplib}
%    \ExplSyntaxOn
%    \color_model_new:nnn { pantone1215 }
%      { Separation }
%      {
%        name = PANTONE~1215~U ,
%        alternative-model = cmyk ,
%        alternative-values = {0, 0.15, 0.51, 0}
%      }
%    \color_model_new:nnn { pantone+black }
%      { DeviceN }
%      { names = {pantone1215,black} }
%    \color_set:nnn{purepantone}{pantone+black}{1,0}
%    \color_set:nnn{pureblack}  {pantone+black}{0,1}
%    \ExplSyntaxOff
%    \begin{document}
%    \mpfig
%      fill unitsquare xscaled \mpdim{\textwidth} yscaled 30
%        withshadingmethod "linear"
%        withshadingcolors ("purepantone","pureblack")
%        ;
%    \endmpfig
%    \end{document}
%\end{verbatim}
%    \begin{macrocode}
    run_tex_code({
      [[\color_export:nnN{]], str, [[}{backend}\mplib_@tempa]],
    },ccexplat)
    local name, value = get_macro'mplib_@tempa':match'{(.-)}{(.-)}'
    local t, obj = res:explode()
    if pdfmode then
      obj = format("%s 0 R", ltx.pdf.object_id( t[1]:sub(2,-1) ))
    else
      obj = t[2]
    end
    return format('(1) withprescript"mplib_spotcolor=%s:%s:%s"', value,obj,name)
  end
  return colorsplit(res)
end

%    \end{macrocode}
% |luamplib.fillandstrokecolor|
%    \begin{macrocode}
do
  local function graphictextcolor (col, filldraw)
    if col:find"^[%d%.:]+$" then
      col = col:explode":"
      for i=1,#col do
        col[i] = format("%.3f", col[i])
      end
      if pdfmode then
        local op = #col == 4 and "k" or #col == 3 and "rg" or "g"
        col[#col+1] = filldraw == "fill" and op or op:upper()
        return tableconcat(col," ")
      end
      return format("[%s]", tableconcat(col," "))
    end
    col = process_color(col):match'"mpliboverridecolor=(.+)"'
    if pdfmode then
      local t = col:explode()
      local b = filldraw == "fill" and 1 or #t/2+1
      local e = b == 1 and #t/2 or #t
      return tableconcat(t," ", b, e)
    end
    if col:find"@pdf.obj" then
      return col:gsub("pdf:bc%s*","",1)
    else
      return format("[%s]", tableconcat(colorsplit(col)," "))
    end
  end
  function luamplib.fillandstrokecolor (fill, stroke)
    fill   = graphictextcolor(fill, "fill")
    stroke = graphictextcolor(stroke, "stroke")
    local bc = pdfmode and "" or "pdf:bc "
    return format('withprescript "mpliboverridecolor=%s%s %s"', bc, fill, stroke)
  end
end

%    \end{macrocode}
%
% Remove trailing zeros for smaller PDF
%    \begin{macrocode}
local decimals = "%.%d+"
local function rmzeros(str) return str:gsub("%.?0+$","") end

%    \end{macrocode}
%
%    common function for mplibgraphictext and mpliboutlinetext
%    \begin{macrocode}
local function getrulemetric (box, curr, bp)
  local running = -1073741824
  local wd,ht,dp = curr.width, curr.height, curr.depth
  wd = wd == running and box.width  or wd
  ht = ht == running and box.height or ht
  dp = dp == running and box.depth  or dp
  if bp then
    return wd/factor, ht/factor, dp/factor
  end
  return wd, ht, dp
end

%    \end{macrocode}
%
%    luamplib's mplibgraphictext operator
%    \begin{macrocode}
do
  if not math.round then
    function math.round(x) return x < 0 and -math.floor(-x + 0.5) or math.floor(x + 0.5) end
  end
  local emboldenfonts = { }
  local function roundupwidth (f, fb)
    local wd = math.round(f.size * fb / factor * 10)
    if wd == 0 and fb ~= 0 then
      wd = 1
    end
    emboldenfonts.width = wd
    return wd
  end
  local function getemboldenwidth (curr, fakebold)
    local width = emboldenfonts.width
    if not width then
      local f
      local function getglyph(n)
        while n do
          if n.head then
            getglyph(n.head)
          elseif n.font and n.font > 0 then
            f = n.font; break
          end
          n = node.getnext(n)
        end
      end
      getglyph(curr)
      width = roundupwidth(font.getcopy(f or font.current()), fakebold)
    end
    return width
  end
  local function getrulewhatsit (line, wd, ht, dp)
    line, wd, ht, dp = line/1000, wd/factor, ht/factor, dp/factor
    line = line == 0 and "" or ("%f w"):format(line)
    local pl
    local fmt = "q %s %f %f %f %f re B Q"
    if pdfmode then
      pl = node.new("whatsit","pdf_literal")
      pl.mode = 0
    else
      fmt = "pdf:content "..fmt
      pl = node.new("whatsit","special")
    end
    pl.data = fmt:format(line, 0, -dp, wd, ht+dp) :gsub(decimals,rmzeros)
    local ss = node.new"glue"
    node.setglue(ss, 0, 65536, 65536, 2, 2)
    pl.next = ss
    return pl
  end
%    \end{macrocode}
% copying attributes of rule/glue node to improve tagging of mplibgraphictext
%    \begin{macrocode}
  local tag_update_attrs
  if is_defined"ver@tagpdf.sty" then
    tag_update_attrs = function (n, curr)
      while n do
        n.attr = curr.attr
        if n.head then
          tag_update_attrs(n.head, curr)
        end
        n = node.getnext(n)
      end
    end
  else
    tag_update_attrs = function() end
  end
  local function embolden (box, curr, fakebold)
    local head = curr
    while curr do
      if curr.head then
        curr.head = embolden(curr, curr.head, fakebold)
      elseif curr.replace then
        curr.replace = embolden(box, curr.replace, fakebold)
      elseif curr.leader then
        if curr.leader.head then
          curr.leader.head = embolden(curr.leader, curr.leader.head, fakebold)
        elseif curr.leader.id == node.id"rule" then
          local glue = node.effective_glue(curr, box)
          local line = getemboldenwidth(curr, fakebold)
          local wd,ht,dp = getrulemetric(box, curr.leader)
          if box.id == node.id"hlist" then
            wd = glue
          else
            ht, dp = 0, glue
          end
          local pl = getrulewhatsit(line, wd, ht, dp)
          local pack = box.id == node.id"hlist" and node.hpack or node.vpack
          local list = pack(pl, glue, "exactly")
          tag_update_attrs(list,curr)
          head = node.insert_after(head, curr, list)
          head, curr = node.remove(head, curr)
        end
      elseif curr.id == node.id"rule" and curr.subtype == 0 then
        local line = getemboldenwidth(curr, fakebold)
        local wd,ht,dp = getrulemetric(box, curr)
        if box.id == node.id"vlist" then
          ht, dp = 0, ht+dp
        end
        local pl = getrulewhatsit(line, wd, ht, dp)
        local list
        if box.id == node.id"hlist" then
          list = node.hpack(pl, wd, "exactly")
        else
          list = node.vpack(pl, ht+dp, "exactly")
        end
        tag_update_attrs(list,curr)
        head = node.insert_after(head, curr, list)
        head, curr = node.remove(head, curr)
      elseif curr.id == node.id"glyph" and curr.font > 0 then
        local f = curr.font
        local key = format("%s:%s",f,fakebold)
        local i = emboldenfonts[key]
        if not i then
          local ft = font.getfont(f) or font.getcopy(f)
          local width = roundupwidth(ft, fakebold)
          if ft.format == "opentype" or ft.format == "truetype" then
            local name = ft.name:gsub('"',''):gsub(';$','')
            local t = name:gsub("^file:",""):gsub("^name:",""):gsub("^kpse:",""):gsub("^my:","")
            name = format('%s%sembolden=%s;',name, t:find":" and ";" or ":", fakebold)
            _, i = fonts.constructors.readanddefine(name,ft.size)
          elseif pdfmode then
            local ft = table.copy(ft)
            ft.mode, ft.width = 2, width
            i = font.define(ft)
          else
            goto skip_type1
          end
          emboldenfonts[key] = i
        end
        curr.font = i
      end
      ::skip_type1::
      curr = node.getnext(curr)
    end
    return head
  end
  luamplib.graphictext = function (text, fakebold, fc, dc)
    local fmt = process_tex_text(text):sub(1,-2)
    local id = tonumber(fmt:match"mplibtexboxid=(%d+):")
    emboldenfonts.width = nil
    local box = texgetbox(id)
    box.head = embolden(box, box.head, fakebold)
    local colors = luamplib.fillandstrokecolor(fc, dc)
    return format('%s %s)', fmt, colors)
  end
end

%    \end{macrocode}
%
%    luamplib's mplibglyph operator
%    \begin{macrocode}
do
  local function mperr (str)
    return format("hide(errmessage %q)", str)
  end
  local function getangle (a,b,c)
    local r = math.deg(math.atan(c.y-b.y, c.x-b.x) - math.atan(b.y-a.y, b.x-a.x))
    if r > 180 then
      r = r - 360
    elseif r < -180 then
      r = r + 360
    end
    return r
  end
  local function turning (t)
    local r, n = 0, #t
    for i=1,2 do
      tableinsert(t, t[i])
    end
    for i=1,n do
      r = r + getangle(t[i], t[i+1], t[i+2])
    end
    return r/360
  end
  local function glyphimage(t, fmt)
    local q, p, r, towarn = {{},{}}
    local function closepath(dots)
      tableinsert(p, format("%scycle", dots or "--"))
      tableinsert(q[ turning(r) > 0 and 1 or 2 ], tableconcat(p))
    end
    for i,v in ipairs(t) do
      local cmd = v[#v]
      local nt = t[i+1]
      local final = not nt or nt[#nt] ~= "l" and nt[#nt] ~= "c"
      if cmd == "m" then
        if final then towarn = true end
        p = {format('(%s,%s)',v[1],v[2])}
        r = {{x=v[1],y=v[2]}}
      else
        if cmd == "l" then
          local pt = t[i-1]
          if (final or pt and pt[#pt] == "m") and r[1].x == v[1] and r[1].y == v[2] then
          else
            tableinsert(p, format('--(%s,%s)',v[1],v[2]))
            tableinsert(r, {x=v[1],y=v[2]})
          end
          if final then closepath() end
        elseif cmd == "c" then
          tableinsert(p, format('..controls(%s,%s)and(%s,%s)',v[1],v[2],v[3],v[4]))
          if final and r[1].x == v[5] and r[1].y == v[6] then
            closepath ".."
          else
            tableinsert(p, format('..(%s,%s)',v[5],v[6]))
            tableinsert(r, {x=v[5],y=v[6]})
            if final then closepath() end
          end
        elseif cmd == "path" or cmd == "move" then
        else
          return mperr"unknown operator"
        end
      end
    end
    r = { }
    if fmt == "opentype" then
      for _,v in ipairs(q[1]) do
        tableinsert(r, format('addto currentpicture contour %s;',v))
      end
      for _,v in ipairs(q[2]) do
        tableinsert(r, format('addto currentpicture contour %s withcolor background;',v))
      end
    else
      for _,v in ipairs(q[2]) do
        tableinsert(r, format('addto currentpicture contour %s;',v))
      end
      for _,v in ipairs(q[1]) do
        tableinsert(r, format('addto currentpicture contour %s withcolor background;',v))
      end
    end
    return format('image(%s)', tableconcat(r)), towarn
  end
  if not table.tofile then require"lualibs-lpeg"; require"lualibs-table"; end
  function luamplib.glyph (f, c)
    local filename, subfont, instance, kind, shapedata
    local fid = tonumber(f) or font.id(f)
    if fid > 0 then
      local fontdata = font.getfont(fid) or font.getcopy(fid)
      filename, subfont, kind = fontdata.filename, fontdata.subfont, fontdata.format
      instance = fontdata.specification and fontdata.specification.instance
        or fontdata.shared and fontdata.shared.features.axis
      filename = filename and filename:gsub("^harfloaded:","")
    else
      local name
      f = f:match"^%s*(.+)%s*$"
      name, subfont, instance = f:match"(.+)%((%d+)%)%[(.-)%]$"
      if not name then
        name, instance = f:match"(.+)%[(.-)%]$" -- SourceHanSansK-VF.otf[Heavy]
      end
      if not name then
        name, subfont = f:match"(.+)%((%d+)%)$" -- Times.ttc(2)
      end
      name = name or f
      subfont = (subfont or 0)+1
      instance = instance and instance:lower()
      for _,ftype in ipairs{"opentype", "truetype"} do
        filename = kpse.find_file(name, ftype.." fonts")
        if filename then
          kind = ftype; break
        end
      end
    end
    if kind ~= "opentype" and kind ~= "truetype" then
      f = fid and fid > 0 and tex.fontname(fid) or f
      if kpse.find_file(f, "tfm") then
        return format("glyph %s of %q", tonumber(c) or format("%q",c), f)
      else
        filename = kpse.find_file(f, "type1 fonts")
        if filename then
          kind = "type1" -- there's bug in processing cmr family
        else
          return mperr"font not found"
        end
      end
    end
    local time = lfsattributes(filename,"modification")
%    \end{macrocode}
%\begin{verbatim}
%   local k = format("shapes_%s(%s)[%s]%s", filename, subfont or "", instance or "",
%                     luaotfload and luaotfload.version or "")
%\end{verbatim}
%  ^^X replace next line with prev one in 2027.
%    \begin{macrocode}
    local k = format("shapes_%s(%s)[%s]", filename, subfont or "", instance or "")
    local h = format(string.rep('%02x', 256/8), string.byte(sha2.digest256(k), 1, -1))
    local newname = format("%s/%s.lua", cachedir or outputdir(), h)
    local newtime = lfsattributes(newname,"modification") or 0
    if time == newtime then
      shapedata = require(newname)
    end
    if not shapedata then
      if fonts then
        local handler = kind == "type1" and fonts.handlers.afm or fonts.handlers.otf
        shapedata = handler.readers.loadshapes(filename,subfont,instance)
      end
      if not shapedata then return mperr"loadshapes() failed. luaotfload not loaded?" end
      table.tofile(newname, shapedata, "return")
      lfstouch(newname, time, time)
    end
    local gid = tonumber(c)
    if not gid then
      local uni = utf8.codepoint(c)
      for i,v in pairs(shapedata.glyphs) do
        if c == v.name or uni == v.unicode then
          gid = i; break
        end
      end
    end
    if not gid then return mperr"cannot get GID (glyph id)" end
    local fac = 1000 / (shapedata.units or 1000)
    local t = shapedata.glyphs[gid]; t = t and t.segments
    if not t then return "image()" end
    for i,v in ipairs(t) do
      if type(v) == "table" then
        for ii,vv in ipairs(v) do
          if type(vv) == "number" then
            t[i][ii] = format("%.0f", vv * fac)
          end
        end
      end
    end
    local result, towarn = glyphimage(t, shapedata.format or kind)
    if towarn then
      warn("mplibglyph %s not working properly. Use glyph instead", f)
    end
    return result
  end
end

%    \end{macrocode}
%
%    mpliboutlinetext : based on mkiv's font-mps.lua
%    \begin{macrocode}
do
  local rulefmt = "mpliboutlinepic[%i]:=image(addto currentpicture contour \z
    unitsquare shifted - center unitsquare;) xscaled %f yscaled %f shifted (%f,%f);"
  local outline_horz, outline_vert
  function outline_vert (res, box, curr, xshift, yshift)
    local b2u = box.dir == "LTL"
    local dy = (b2u and -box.depth or box.height)/factor
    local ody = dy
    while curr do
      if curr.id == node.id"rule" then
        local wd, ht, dp = getrulemetric(box, curr, true)
        local hd = ht + dp
        if hd ~= 0 then
          dy = dy + (b2u and dp or -ht)
          if wd ~= 0 and curr.subtype == 0 then
            res[#res+1] = rulefmt:format(#res+1, wd, hd, xshift+wd/2, yshift+dy+(ht-dp)/2)
          end
          dy = dy + (b2u and ht or -dp)
        end
      elseif curr.id == node.id"glue" then
        local vwidth = node.effective_glue(curr,box)/factor
        if curr.leader then
          local curr, kind = curr.leader, curr.subtype
          if curr.id == node.id"rule" then
            local wd = getrulemetric(box, curr, true)
            if wd ~= 0 then
              local hd = vwidth
              local dy = dy + (b2u and 0 or -hd)
              if hd ~= 0 and curr.subtype == 0 then
                res[#res+1] = rulefmt:format(#res+1, wd, hd, xshift+wd/2, yshift+dy+hd/2)
              end
            end
          elseif curr.head then
            local hd = (curr.height + curr.depth)/factor
            if hd <= vwidth then
              local dy, n, iy = dy, 0, 0
              if kind == 100 or kind == 103 then -- todo: gleaders
                local ady = abs(ody - dy)
                local ndy = math.ceil(ady / hd) * hd
                local diff = ndy - ady
                n = math.floor((vwidth-diff) / hd)
                dy = dy + (b2u and diff or -diff)
              else
                n = math.floor(vwidth / hd)
                if kind == 101 then
                  local side = vwidth % hd / 2
                  dy = dy + (b2u and side or -side)
                elseif kind == 102 then
                  iy = vwidth % hd / (n+1)
                  dy = dy + (b2u and iy or -iy)
                end
              end
              dy = dy + (b2u and curr.depth or -curr.height)/factor
              hd = b2u and hd or -hd
              iy = b2u and iy or -iy
              local func = curr.id == node.id"hlist" and outline_horz or outline_vert
              for i=1,n do
                res = func(res, curr, curr.head, xshift+curr.shift/factor, yshift+dy)
                dy = dy + hd + iy
              end
            end
          end
        end
        dy = dy + (b2u and vwidth or -vwidth)
      elseif curr.id == node.id"kern" then
        dy = dy + curr.kern/factor * (b2u and 1 or -1)
      elseif curr.id == node.id"vlist" then
        dy = dy + (b2u and curr.depth or -curr.height)/factor
        res = outline_vert(res, curr, curr.head, xshift+curr.shift/factor, yshift+dy)
        dy = dy + (b2u and curr.height or -curr.depth)/factor
      elseif curr.id == node.id"hlist" then
        dy = dy + (b2u and curr.depth or -curr.height)/factor
        res = outline_horz(res, curr, curr.head, xshift+curr.shift/factor, yshift+dy)
        dy = dy + (b2u and curr.height or -curr.depth)/factor
      end
      curr = node.getnext(curr)
    end
    return res
  end
  function outline_horz (res, box, curr, xshift, yshift, discwd)
    local r2l = box.dir == "TRT"
    local dx = r2l and (discwd or box.width/factor) or 0
    local dirs = { { dir = r2l, dx = dx } }
    while curr do
      if curr.id == node.id"dir" then
        local sign, dir = curr.dir:match"(.)(...)"
        local level, newdir = curr.level, r2l
        if sign == "+" then
          newdir = dir == "TRT"
          if r2l ~= newdir then
            local n = node.getnext(curr)
            while n do
              if n.id == node.id"dir" and n.level+1 == level then break end
              n = node.getnext(n)
            end
            n = n or node.tail(curr)
            dx = dx + node.rangedimensions(box, curr, n)/factor * (newdir and 1 or -1)
          end
          dirs[level] = { dir = r2l, dx = dx }
        else
          local level = level + 1
          newdir = dirs[level].dir
          if r2l ~= newdir then
            dx = dirs[level].dx
          end
        end
        r2l = newdir
      elseif curr.char and curr.font and curr.font > 0 then
        local ft = font.getfont(curr.font) or font.getcopy(curr.font)
        local gid = ft.characters[curr.char].index or curr.char
        local scale = ft.size / factor / 1000
        local slant   = (ft.slant or 0)/1000
        local extend  = (ft.extend or 1000)/1000
        local squeeze = (ft.squeeze or 1000)/1000
        local expand  = 1 + (curr.expansion_factor or 0)/1000000
        local xscale, yscale = scale * extend * expand, scale * squeeze
        dx = dx - (r2l and curr.width/factor*expand or 0)
        local xoff, yoff = (curr.xoffset or 0)/factor, (curr.yoffset or 0)/factor
        local xpos, ypos = dx + xshift + xoff, yshift + yoff
        local vertical = ""
        if ft.shared and (ft.shared.features.vert or ft.shared.features.vrt2) then
          if ft.shared.features.vertical then -- luatexko
            vertical = "rotated 90"
            local data = ft.characters[curr.char] or { }
            if ft.hb then
              local hoff, voff = (data.luatexko_hoff or 0)/factor, (data.luatexko_voff or 0)/factor
              local charraise = (ft.luatexko_charraise or 0)/factor
              xpos, ypos = xpos - voff + hoff - charraise, ypos + hoff + voff + charraise
            else
              local cmds = data.commands or { {0,0}, {0,0} }
              local voff, hoff = -cmds[1][2]/factor, cmds[2][2]/factor
              xpos, ypos = xpos + hoff, ypos + voff
            end
          elseif curr ~= box.head then -- luatexja
            vertical = "rotated 90"
            local en = ft.parameters.quad/factor/2
            xpos, ypos = xpos - xoff - yoff + en, ypos - yoff + xoff - en
          end
        end
        local image
        if ft.format == "opentype" or ft.format == "truetype" then
          image = luamplib.glyph(curr.font, gid)
        else
          local name, scale = ft.name, 1
          local vf = font.read_vf(name, ft.size)
          if vf and vf.characters[gid] then
            local cmds = vf.characters[gid].commands or {}
            for _,v in ipairs(cmds) do
              if v[1] == "char" then
                gid = v[2]
              elseif v[1] == "font" and vf.fonts[v[2]] then
                name  = vf.fonts[v[2]].name
                scale = vf.fonts[v[2]].size / ft.size
              end
            end
          end
          image = format("glyph %s of %q scaled %f", gid, name, scale)
        end
        res[#res+1] = format("mpliboutlinepic[%i]:=%s xscaled %f yscaled %f slanted %f %s shifted (%f,%f);",
                             #res+1, image, xscale, yscale, slant, vertical, xpos, ypos)
        dx = dx + (r2l and 0 or curr.width/factor*expand)
      elseif curr.replace then
        local width = node.dimensions(curr.replace)/factor
        dx = dx - (r2l and width or 0)
        res = outline_horz(res, box, curr.replace, xshift+dx, yshift, width)
        dx = dx + (r2l and 0 or width)
      elseif curr.id == node.id"rule" then
        local wd, ht, dp = getrulemetric(box, curr, true)
        if wd ~= 0 then
          local hd = ht + dp
          dx = dx - (r2l and wd or 0)
          if hd ~= 0 and curr.subtype == 0 then
            res[#res+1] = rulefmt:format(#res+1, wd, hd, xshift+dx+wd/2, yshift+(ht-dp)/2)
          end
          dx = dx + (r2l and 0 or wd)
        end
      elseif curr.id == node.id"glue" then
        local width = node.effective_glue(curr, box)/factor
        dx = dx - (r2l and width or 0)
        if curr.leader then
          local curr, kind = curr.leader, curr.subtype
          if curr.id == node.id"rule" then
            local wd, ht, dp = getrulemetric(box, curr, true)
            local hd = ht + dp
            if hd ~= 0 then
              wd = width
              if wd ~= 0 and curr.subtype == 0 then
                res[#res+1] = rulefmt:format(#res+1, wd, hd, xshift+dx+wd/2, yshift+(ht-dp)/2)
              end
            end
          elseif curr.head then
            local wd = curr.width/factor
            if wd <= width then
              local dx = r2l and dx+width or dx
              local n, ix = 0, 0
              if kind == 100 or kind == 103 then -- todo: gleaders
                local adx = abs(dx-dirs[1].dx)
                local ndx = math.ceil(adx / wd) * wd
                local diff = ndx - adx
                n = math.floor((width-diff) / wd)
                dx = dx + (r2l and -diff-wd or diff)
              else
                n = math.floor(width / wd)
                if kind == 101 then
                  local side = width % wd /2
                  dx = dx + (r2l and -side-wd or side)
                elseif kind == 102 then
                  ix = width % wd / (n+1)
                  dx = dx + (r2l and -ix-wd or ix)
                end
              end
              wd = r2l and -wd or wd
              ix = r2l and -ix or ix
              local func = curr.id == node.id"hlist" and outline_horz or outline_vert
              for i=1,n do
                res = func(res, curr, curr.head, xshift+dx, yshift-curr.shift/factor)
                dx = dx + wd + ix
              end
            end
          end
        end
        dx = dx + (r2l and 0 or width)
      elseif curr.id == node.id"kern" then
        dx = dx + curr.kern/factor * (r2l and -1 or 1)
      elseif curr.id == node.id"math" then
        dx = dx + curr.surround/factor * (r2l and -1 or 1)
      elseif curr.id == node.id"vlist" then
        dx = dx - (r2l and curr.width/factor or 0)
        res = outline_vert(res, curr, curr.head, xshift+dx, yshift-curr.shift/factor)
        dx = dx + (r2l and 0 or curr.width/factor)
      elseif curr.id == node.id"hlist" then
        dx = dx - (r2l and curr.width/factor or 0)
        res = outline_horz(res, curr, curr.head, xshift+dx, yshift-curr.shift/factor)
        dx = dx + (r2l and 0 or curr.width/factor)
      end
      curr = node.getnext(curr)
    end
    return res
  end
  function luamplib.outlinetext (text)
    local fmt = process_tex_text(text)
    local id  = tonumber(fmt:match"mplibtexboxid=(%d+):")
    local box = texgetbox(id)
    local res = outline_horz({ }, box, box.head, 0, 0)
    if #res == 0 then res = { "mpliboutlinepic[1]:=image();" } end
    return tableconcat(res) .. format("mpliboutlinenum:=%i;", #res)
  end
end

%    \end{macrocode}
%
%    lua functions for |mplib(uc)substring ... of ...|
%    \begin{macrocode}
function luamplib.getunicodegraphemes (s)
  local t = { }
  local graphemes = require'lua-uni-graphemes'
  for _, _, c in graphemes.graphemes(s) do
    table.insert(t, c)
  end
  return t
end
function luamplib.unicodesubstring (s,b,e,grph)
  local tt, t, step = { }
  if grph then
    t = luamplib.getunicodegraphemes(s)
  else
    t = { }
    for _, c in utf8.codes(s) do
      table.insert(t, utf8.char(c))
    end
  end
  if b <= e then
    b, step = b+1, 1
  else
    e, step = e+1, -1
  end
  for i = b, e, step do
    table.insert(tt, t[i])
  end
  s = table.concat(tt):gsub('"','"&ditto&"')
  return string.format('"%s"', s)
end

%    \end{macrocode}
%
%    \metapost preambles
%    \begin{macrocode}
luamplib.preambles = {
  preamble = [[
boolean mplib ; mplib := true ;
let dump = endinput ;
let normalfontsize = fontsize;
input %s ;
]],
  mplibcode = [[
texscriptmode := 2;
def rawtextext primary t = runscript("luamplibtext{"&t&"}") enddef;
def mplibcolor primary t = runscript("luamplibcolor{"&t&"}") enddef;
def mplibdimen primary t = runscript("luamplibdimen{"&t&"}") enddef;
def VerbatimTeX primary t = runscript("luamplibverbtex{"&t&"}") enddef;
if known context_mlib:
  defaultfont := "cmtt10";
  let infont = normalinfont;
  let fontsize = normalfontsize;
  vardef thelabel@#(expr p,z) =
    if string p :
      thelabel@#(p infont defaultfont scaled defaultscale,z)
    else :
      p shifted (z + labeloffset*mfun_laboff@# -
        (mfun_labxf@#*lrcorner p + mfun_labyf@#*ulcorner p +
        (1-mfun_labxf@#-mfun_labyf@#)*llcorner p))
    fi
  enddef;
else:
  vardef textext@# primary t = rawtextext (t) enddef;
  def message expr t =
    if string t: runscript("mp.report[=["&t&"]=]") else: errmessage "Not a string" fi
  enddef;
  def withtransparency (expr a, t) =
    withprescript "tr_alternative=" & if numeric a: decimal fi a
    withprescript "tr_transparency=" & decimal t
  enddef;
  vardef ddecimal primary p =
    decimal xpart p & " " & decimal ypart p
  enddef;
  vardef boundingbox primary p =
    if (path p) or (picture p) :
      llcorner p -- lrcorner p -- urcorner p -- ulcorner p
    else :
      origin
    fi -- cycle
  enddef;
fi
def resolvedcolor(expr s) =
  runscript("return luamplib.shadecolor('"& s &"')")
enddef;
def colordecimals primary c =
  if cmykcolor c:
    decimal cyanpart c & ":" & decimal magentapart c & ":" &
    decimal yellowpart c & ":" & decimal blackpart c
  elseif rgbcolor c:
    decimal redpart c & ":" & decimal greenpart c & ":" & decimal bluepart c
  elseif string c:
    if known graphictextpic: c else: colordecimals resolvedcolor(c) fi
  else:
    decimal c
  fi
enddef;
def externalfigure primary filename =
  draw rawtextext("\includegraphics{"& filename &"}")
enddef;
def TEX = textext enddef;
def mplibtexcolor primary c =
  runscript("return luamplib.gettexcolor('"& c &"')")
enddef;
def mplibrgbtexcolor primary c =
  runscript("return luamplib.gettexcolor('"& c &"','rgb')")
enddef;
def mplibgraphictext primary t =
  begingroup;
  mplibgraphictext_ (t)
enddef;
def mplibgraphictext_ (expr t) text rest =
  save fakebold, scale, fillcolor, drawcolor, withfillcolor, withdrawcolor, strokecolor,
    fb, fc, dc, graphictextpic, alsoordoublepath;
  picture graphictextpic; graphictextpic := nullpicture;
  numeric fb; string fc, dc; fb:=2; fc:="white"; dc:="black";
  let scale = scaled;
  def fakebold  primary c = hide(fb:=c;) enddef;
  def fillcolor primary c = hide(fc:=colordecimals c;) enddef;
  def drawcolor primary c = hide(dc:=colordecimals c;) enddef;
  let withfillcolor = fillcolor; let withdrawcolor = drawcolor; let strokecolor = drawcolor;
  def alsoordoublepath expr p = if picture p: also else: doublepath fi p enddef;
  addto graphictextpic alsoordoublepath (origin--cycle) rest; graphictextpic:=nullpicture;
  def fakebold  primary c = enddef;
  let fillcolor = fakebold; let drawcolor = fakebold;
  let withfillcolor = fillcolor; let withdrawcolor = drawcolor; let strokecolor = drawcolor;
  image(draw runscript("return luamplib.graphictext([===["&t&"]===],"
    & decimal fb &",'"& fc &"','"& dc &"')") rest;)
  endgroup;
enddef;
def mplibglyph expr c of f =
  runscript (
    "return luamplib.glyph('"
    & if numeric f: decimal fi f
    & "','"
    & if numeric c: decimal fi c
    & "')"
  )
enddef;
numeric luamplib_tmp_num_; luamplib_tmp_num_ = 0;
def mplibdrawglyph expr g =
  luamplib_tmp_num_ := 0;
  for item within g:
    fill pathpart item
    if incr luamplib_tmp_num_ < length g: withpostscript "collect"; fi
  endfor
enddef;
let mplibfillglyph = mplibdrawglyph;
def mplibstrokeglyph expr g =
  luamplib_tmp_num_ := 0;
  for item within g:
    draw pathpart item
    if incr luamplib_tmp_num_ < length g: withpostscript "collect"; fi
  endfor
enddef;
def mplibfillandstrokeglyph expr g =
  luamplib_tmp_num_ := 0;
  for item within g:
    draw pathpart item withpostscript
    if incr luamplib_tmp_num_ < length g: "collect"; else: "both" fi
  endfor
enddef;
def withmplibcolors (expr f, s) =
  runscript("return luamplib.fillandstrokecolor('" &
    if not string f: colordecimals fi f & "','" &
    if not string s: colordecimals fi s & "')")
enddef;
def withmplibopacities (expr a, f, s) =
  withprescript "tr_alternative=" & if numeric a: decimal fi a
  withprescript "tr_transparency=" & decimal f & ":" & decimal s
enddef;
def mplib_do_outline_text_set_b (text f) (text d) text r =
  def mplib_do_outline_options_f = f enddef;
  def mplib_do_outline_options_d = d enddef;
  def mplib_do_outline_options_r = r enddef;
enddef;
def mplib_do_outline_text_set_f (text f) text r =
  def mplib_do_outline_options_f = f enddef;
  def mplib_do_outline_options_r = r enddef;
enddef;
def mplib_do_outline_text_set_u (text f) text r =
  def mplib_do_outline_options_f = f enddef;
enddef;
def mplib_do_outline_text_set_d (text d) text r =
  def mplib_do_outline_options_d = d enddef;
  def mplib_do_outline_options_r = r enddef;
enddef;
def mplib_do_outline_text_set_r (text d) (text f) text r =
  def mplib_do_outline_options_d = d enddef;
  def mplib_do_outline_options_f = f enddef;
  def mplib_do_outline_options_r = r enddef;
enddef;
def mplib_do_outline_text_set_n text r =
  def mplib_do_outline_options_r = r enddef;
enddef;
def mplib_do_outline_text_set_p = enddef;
def mplib_fill_outline_text =
  for n=1 upto mpliboutlinenum:
    i:=0;
    for item within mpliboutlinepic[n]:
      i:=i+1;
      fill pathpart item mplib_do_outline_options_f withpen pencircle scaled 0
      if (n<mpliboutlinenum) or (i<length mpliboutlinepic[n]): withpostscript "collect"; fi
    endfor
  endfor
enddef;
def mplib_draw_outline_text =
  for n=1 upto mpliboutlinenum:
    for item within mpliboutlinepic[n]:
      draw pathpart item mplib_do_outline_options_d;
    endfor
  endfor
enddef;
def mplib_filldraw_outline_text =
  for n=1 upto mpliboutlinenum:
    i:=0;
    for item within mpliboutlinepic[n]:
      i:=i+1;
      if (n<mpliboutlinenum) or (i<length mpliboutlinepic[n]):
        fill pathpart item mplib_do_outline_options_f withpostscript "collect";
      else:
        draw pathpart item mplib_do_outline_options_f withpostscript "both";
      fi
    endfor
  endfor
enddef;
vardef mpliboutlinetext@# (expr t) text rest =
  save kind; string kind; kind := str @#;
  save i; numeric i;
  picture mpliboutlinepic[]; numeric mpliboutlinenum;
  def mplib_do_outline_options_d = enddef;
  def mplib_do_outline_options_f = enddef;
  def mplib_do_outline_options_r = enddef;
  runscript("return luamplib.outlinetext[===["&t&"]===]");
  image ( addto currentpicture also image (
    if kind = "f":
      mplib_do_outline_text_set_f rest;
      mplib_fill_outline_text;
    elseif kind = "d":
      mplib_do_outline_text_set_d rest;
      mplib_draw_outline_text;
    elseif kind = "b":
      mplib_do_outline_text_set_b rest;
      mplib_fill_outline_text;
      mplib_draw_outline_text;
    elseif kind = "u":
      mplib_do_outline_text_set_u rest;
      mplib_filldraw_outline_text;
    elseif kind = "r":
      mplib_do_outline_text_set_r rest;
      mplib_draw_outline_text;
      mplib_fill_outline_text;
    elseif kind = "p":
      mplib_do_outline_text_set_p;
      mplib_draw_outline_text;
    else:
      mplib_do_outline_text_set_n rest;
      mplib_fill_outline_text;
    fi;
  ) mplib_do_outline_options_r; )
enddef ;
def withmppattern primary p =
  withprescript "mplibpattern=" & if numeric p: decimal fi p
enddef;
primarydef t withpattern p =
  image(
    if cycle t:
      fill
    else:
      draw
    fi
    t withprescript "mplibpattern=" & if numeric p: decimal fi p; )
enddef;
vardef mplibtransformmatrix (text e) =
  save t; transform t;
  t = identity e;
  runscript("luamplib.transformmatrix = {"
  & decimal xxpart t & ","
  & decimal yxpart t & ","
  & decimal xypart t & ","
  & decimal yypart t & ","
  & decimal xpart  t & ","
  & decimal ypart  t & ","
  & "}");
enddef;
primarydef p withmaskinggroup s =
  if picture p:
    image(
      draw p;
      draw center p withprescript "mplibfadestate=stop";
    )
  else:
    p withprescript "mplibfadestate=stop"
  fi
  withprescript "mplibfadetype=masking"
  withprescript "mplibmaskname=" & s
enddef;
def withmaskingbgcolor expr c =
  withprescript "mplibmaskingbgcolor=" & colordecimals c
enddef;
primarydef p withfademethod s =
  if picture p:
    image(
      draw p;
      draw center p withprescript "mplibfadestate=stop";
    )
  else:
    p withprescript "mplibfadestate=stop"
  fi
    withprescript "mplibfadetype=" & s
    hide(mplib_shade_step := 1;)
    withprescript "sh_color_a=1"
    withprescript "sh_color_b=0"
    withprescript "mplibfadebbox=" &
      decimal (xpart llcorner p -1/4) & ":" &
      decimal (ypart llcorner p -1/4) & ":" &
      decimal (xpart urcorner p +1/4) & ":" &
      decimal (ypart urcorner p +1/4)
enddef;
def withfadevector (expr a,b) =
  withprescript "mplibfadevector=" &
    decimal xpart a & ":" &
    decimal ypart a & ":" &
    decimal xpart b & ":" &
    decimal ypart b
enddef;
let withfadecenter = withfadevector;
def withfaderadius (expr a,b) =
  withprescript "mplibfaderadius=" &
    decimal a & ":" &
    decimal b
enddef;
def withfadebbox (expr a,b) =
  withprescript "mplibfadebbox=" &
    decimal xpart a & ":" &
    decimal ypart a & ":" &
    decimal xpart b & ":" &
    decimal ypart b
enddef;
primarydef p asgroup s =
  image(
    draw center p
      withprescript "mplibgroupbbox=" &
        decimal (xpart llcorner p -1/4) & ":" &
        decimal (ypart llcorner p -1/4) & ":" &
        decimal (xpart urcorner p +1/4) & ":" &
        decimal (ypart urcorner p +1/4)
      withprescript "gr_state=start"
      withprescript "gr_type=" & s;
    draw p withprescript "sh_in_xobj=yes";
    draw center p withprescript "gr_state=stop";
  )
enddef;
def withgroupbbox (expr a,b) =
  withprescript "mplibgroupbbox=" &
    decimal xpart a & ":" &
    decimal ypart a & ":" &
    decimal xpart b & ":" &
    decimal ypart b
enddef;
def withgroupname expr s =
  withprescript "mplibgroupname=" & s
enddef;
def usemplibgroup primary s =
  draw maketext("\luamplibtagasgroupput{"& s &"}{\csname luamplib.group."& s &"\endcsname}")
    shifted runscript("return luamplib.trgroupshifts['" & s & "']")
enddef;
path    mplib_shade_path ;
numeric mplib_shade_step ; mplib_shade_step := 0 ;
numeric mplib_shade_fx, mplib_shade_fy ;
numeric mplib_shade_lx, mplib_shade_ly ;
numeric mplib_shade_nx, mplib_shade_ny ;
numeric mplib_shade_dx, mplib_shade_dy ;
numeric mplib_shade_tx, mplib_shade_ty ;
primarydef p withshadingmethod m =
  p
  if picture p :
    withprescript "sh_operand_type=picture"
    if textual p or (length p > 1):
      withprescript "sh_transform=no"
      mplib_with_shade_method (boundingbox p, m)
    else:
      withprescript "sh_transform=yes"
      mplib_with_shade_method (pathpart p, m)
    fi
  else :
    withprescript "sh_transform=yes"
    mplib_with_shade_method (p, m)
  fi
enddef;
def mplib_with_shade_method (expr p, m) =
  hide(mplib_with_shade_method_analyze(p))
  withprescript "sh_domain=0 1"
  withprescript "sh_color=into"
  withprescript "sh_color_a=" & colordecimals white
  withprescript "sh_color_b=" & colordecimals black
  withprescript "sh_first=" & ddecimal point 0 of p
  withprescript "sh_set_x=" & ddecimal (mplib_shade_nx,mplib_shade_lx)
  withprescript "sh_set_y=" & ddecimal (mplib_shade_ny,mplib_shade_ly)
  if m = "linear" :
    withprescript "sh_type=linear"
    withprescript "sh_factor=1"
    withprescript "sh_center_a=" & ddecimal llcorner p
    withprescript "sh_center_b=" & ddecimal urcorner p
  else :
    withprescript "sh_type=circular"
    withprescript "sh_factor=1.2"
    withprescript "sh_center_a=" & ddecimal center p
    withprescript "sh_center_b=" & ddecimal center p
    withprescript "sh_radius_a=" & decimal 0
    withprescript "sh_radius_b=" & decimal mplib_max_radius(p)
  fi
enddef;
def mplib_with_shade_method_analyze(expr p) =
  mplib_shade_path := p ;
  mplib_shade_step := 1 ;
  mplib_shade_fx   := xpart point 0 of p ;
  mplib_shade_fy   := ypart point 0 of p ;
  mplib_shade_lx   := mplib_shade_fx ;
  mplib_shade_ly   := mplib_shade_fy ;
  mplib_shade_nx   := 0 ;
  mplib_shade_ny   := 0 ;
  mplib_shade_dx   := abs(mplib_shade_fx - mplib_shade_lx) ;
  mplib_shade_dy   := abs(mplib_shade_fy - mplib_shade_ly) ;
  for i=1 upto length(p) :
    mplib_shade_tx := abs(mplib_shade_fx - xpart point i of p) ;
    mplib_shade_ty := abs(mplib_shade_fy - ypart point i of p) ;
    if mplib_shade_tx > mplib_shade_dx :
      mplib_shade_nx := i + 1 ;
      mplib_shade_lx := xpart point i of p ;
      mplib_shade_dx := mplib_shade_tx ;
    fi ;
    if mplib_shade_ty > mplib_shade_dy :
      mplib_shade_ny := i + 1 ;
      mplib_shade_ly := ypart point i of p ;
      mplib_shade_dy := mplib_shade_ty ;
    fi ;
  endfor ;
enddef;
vardef mplib_max_radius(expr p) =
  max (
    (xpart center   p - xpart llcorner p) ++ (ypart center   p - ypart llcorner p),
    (xpart center   p - xpart ulcorner p) ++ (ypart ulcorner p - ypart center   p),
    (xpart lrcorner p - xpart center   p) ++ (ypart center   p - ypart lrcorner p),
    (xpart urcorner p - xpart center   p) ++ (ypart urcorner p - ypart center   p)
  )
enddef;
def withshadingstep (text t) =
  hide(mplib_shade_step := mplib_shade_step + 1 ;)
  withprescript "sh_step=" & decimal mplib_shade_step
  t
enddef;
let withfadestep = withshadingstep;
def withshadingradius expr a =
  withprescript "sh_radius_a=" & decimal (xpart a)
  withprescript "sh_radius_b=" & decimal (ypart a)
enddef;
def withshadingorigin expr a =
  withprescript "sh_center_a=" & ddecimal a
  withprescript "sh_center_b=" & ddecimal a
enddef;
def withshadingvector expr a =
  withprescript "sh_center_a=" & ddecimal (point xpart a of mplib_shade_path)
  withprescript "sh_center_b=" & ddecimal (point ypart a of mplib_shade_path)
enddef;
def withshadingdirection expr a =
  withprescript "sh_center_a=" & ddecimal (point xpart a of boundingbox(mplib_shade_path))
  withprescript "sh_center_b=" & ddecimal (point ypart a of boundingbox(mplib_shade_path))
enddef;
def withshadingtransform expr a =
  withprescript "sh_transform=" & a
enddef;
def withshadingcenter expr a =
  withprescript "sh_center_a=" & ddecimal (
    center mplib_shade_path shifted (
      xpart a * xpart (lrcorner mplib_shade_path - llcorner mplib_shade_path)/2,
      ypart a * ypart (urcorner mplib_shade_path - lrcorner mplib_shade_path)/2
    )
  )
enddef;
def withshadingcenters (expr a, b) =
  withprescript "sh_center_a=" & ddecimal a
  withprescript "sh_center_b=" & ddecimal b
  withshadingtransform "no"
  withshadingfactor 1
enddef;
let withshadingpoints = withshadingcenters;
def withshadingextend (expr a, b) =
  withprescript "sh_extend=" &
    if a: "true" else: "false" fi & " " &
    if b: "true" else: "false" fi
enddef;
let withfadeextend = withshadingextend;
def withshadingdomain expr d =
  withprescript "sh_domain=" & ddecimal d
enddef;
def withshadingfactor expr f =
  withprescript "sh_factor=" & decimal f
enddef;
def withshadingfraction expr a =
  if mplib_shade_step > 0 :
    withprescript "sh_fraction_" & decimal mplib_shade_step & "=" & decimal a
  fi
enddef;
let withfadefraction = withshadingfraction;
def withshadingcolors (expr a, b) =
  if mplib_shade_step > 0 :
    withprescript "sh_color=into"
    withprescript "sh_color_a_" & decimal mplib_shade_step & "=" & colordecimals a
    withprescript "sh_color_b_" & decimal mplib_shade_step & "=" & colordecimals b
  else :
    withprescript "sh_color=into"
    withprescript "sh_color_a=" & colordecimals a
    withprescript "sh_color_b=" & colordecimals b
  fi
enddef;
let withfadeopacity = withshadingcolors;
def withshadingstroke expr a =
  withprescript "sh_stroking=" & a
enddef;
def withshadingmatrix expr s =
  withprescript "sh_matrix=" & s
enddef;
let withfadematrix = withshadingmatrix;
def mpliblength primary t =
  runscript("return utf8.len[===[" & t & "]===]")
enddef;
def mplibsubstring expr p of t =
  runscript("return luamplib.unicodesubstring([===[" & t & "]===],"
    & decimal xpart p & ","
    & decimal ypart p & ")")
enddef;
def mplibuclength primary t =
  runscript("return #luamplib.getunicodegraphemes[===[" & t & "]===]")
enddef;
def mplibucsubstring expr p of t =
  runscript("return luamplib.unicodesubstring([===[" & t & "]===],"
    & decimal xpart p & ","
    & decimal ypart p & ",true)")
enddef;
]],
  legacyverbatimtex = [[
def specialVerbatimTeX (text t) = runscript("luamplibprefig{"&t&"}") enddef;
def normalVerbatimTeX  (text t) = runscript("luamplibinfig{"&t&"}") enddef;
let VerbatimTeX = specialVerbatimTeX;
extra_beginfig := extra_beginfig & " let VerbatimTeX = normalVerbatimTeX;"&
  "runscript(" &ditto& "luamplib.in_the_fig=true" &ditto& ");";
extra_endfig := extra_endfig & " let VerbatimTeX = specialVerbatimTeX;"&
  "runscript(" &ditto&
  "if luamplib.in_the_fig then luamplib.figid=luamplib.figid+1 end "&
  "luamplib.in_the_fig=false" &ditto& ");";
]],
  textextlabel = [[
let luampliboriginalinfont = infont;
primarydef s infont f =
  if   (s < char 32)
    or (s = char 35) % #
    or (s = char 36) % $
    or (s = char 37) % %
    or (s = char 38) % &
    or (s = char 92) % \
    or (s = char 94) % ^
    or (s = char 95) % _
    or (s = char 123) % {
    or (s = char 125) % }
    or (s = char 126) % ~
    or (s = char 127) :
    s luampliboriginalinfont f
  else :
    rawtextext(s)
  fi
enddef;
def fontsize expr f =
  begingroup
  save size; numeric size;
  size := mplibdimen("1em");
  if size = 0: 10pt else: size fi
  endgroup
enddef;
]],
}

%    \end{macrocode}
%
%   |process_mplibcode|
%
%    When \cs{mplibverbatim} is enabled, do not expand |mplibcode| data.
%    \begin{macrocode}
luamplib.verbatiminput = false
luamplib.everymplib    = setmetatable({ [""] = "" },{ __index = function(t) return t[""] end })
luamplib.everyendmplib = setmetatable({ [""] = "" },{ __index = function(t) return t[""] end })
function luamplib.process_mplibcode (data, instancename)
  texboxes.localid = 4096
%    \end{macrocode}
%    This is needed for legacy behavior
%    \begin{macrocode}
  if luamplib.legacyverbatimtex then
    luamplib.figid, tex_code_pre_mplib = 1, {}
  end
  local everymplib    = luamplib.everymplib[instancename]
  local everyendmplib = luamplib.everyendmplib[instancename]
  data = format("\n%s\n%s\n%s\n",everymplib, data, everyendmplib)
  :gsub("\r","\n")
%    \end{macrocode}
%    These five lines are needed for |mplibverbatim| mode.
%    \begin{macrocode}
  if luamplib.verbatiminput then
    data = data:gsub("\\mpcolor%s+(.-%b{})","mplibcolor(\"%1\")")
    :gsub("\\mpdim%s+(%b{})", "mplibdimen(\"%1\")")
    :gsub("\\mpdim%s+(\\%a+)","mplibdimen(\"%1\")")
    :gsub(btex_etex, "btex %1 etex ")
    :gsub(verbatimtex_etex, "verbatimtex %1 etex;")
  else
%    \end{macrocode}
%    If not |mplibverbatim|, expand |mplibcode| data,
%    so that users can use \TeX\ codes in it.
%    It has turned out that no comment sign is allowed.
%    However, we do not expand |btex| |...| |etex|, |verbatimtex| |...| |etex|, and
%    string expressions.
%    \begin{macrocode}
    local t = { } -- to store btex, verbatimtex, string
    data = data:gsub(btex_etex, function(str)
      t[#t+1] = str
      return format("btex \\unexpanded{!l!u!a!%s!m!p!l!} etex ",  #t) -- space
    end)
    :gsub(verbatimtex_etex, function(str)
      t[#t+1] = str
      return format("verbatimtex \\unexpanded{!l!u!a!%s!m!p!l!} etex;", #t) -- semicolon
    end)
    :gsub('"(.-)"', function(str)
      t[#t+1] = str
      return format('"\\unexpanded{!l!u!a!%s!m!p!l!}"', #t)
    end)
    :gsub("\\%%", "\0PerCent\0")
    :gsub("%%.-\n","\n")
    :gsub("%zPerCent%z", "\\%%")
    run_tex_code(format("\\mplibtmptoks\\expandafter{\\expanded{%s}}",data))
    data = texgettoks"mplibtmptoks"
%    \end{macrocode}
%    Next line to address issue \#55
%    \begin{macrocode}
    :gsub("##", "#")
    :gsub("!l!u!a!(%d+)!m!p!l!", function(str) return t[tonumber(str)] or str end)
  end
  process(data, instancename)
end

%    \end{macrocode}
%
%     pdfliterals will be stored in |figcontents| table, and written to pdf in one go
%     at the end of the flushing figure.
%     Subtable |post| is for the legacy behavior.
%    \begin{macrocode}
local figcontents = { post = { } }
local function put2output(a,...)
  figcontents[#figcontents+1] = type(a) == "string" and format(a,...) or a
end
local function pdf_startfigure(n,llx,lly,urx,ury)
  put2output("\\mplibstarttoPDF{%f}{%f}{%f}{%f}",llx,lly,urx,ury)
end
local function pdf_stopfigure()
  put2output("\\mplibstoptoPDF")
end
%    \end{macrocode}
%    |tex.sprint| with catcode regime -2, as sometimes |#| gets doubled
%    in the argument of pdfliteral.
%    \begin{macrocode}
local function pdf_literalcode (...)
  put2output{ -2, (format(...) :gsub(decimals,rmzeros)) }
end
local start_pdf_code = pdfmode
  and function() pdf_literalcode"q" end
  or  function() put2output"\\special{pdf:bcontent}" end
local stop_pdf_code = pdfmode
  and function() pdf_literalcode"Q" end
  or  function() put2output"\\special{pdf:econtent}" end

%    \end{macrocode}
%
%    Now we process hboxes created from |btex| |...| |etex| or
%    |textext(...)| or |TEX(...)| etc.
%    \begin{macrocode}
local function put_tex_boxes (object,prescript)
  local box = prescript.mplibtexboxid:explode":"
  local n,tw,th = box[1],tonumber(box[2]),tonumber(box[3])
  if n and tw and th then
    local op = object.path
    local first, second, fourth = op[1], op[2], op[4]
    local tx, ty = first.x_coord, first.y_coord
    local sx, rx, ry, sy = 1, 0, 0, 1
    if tw ~= 0 then
      sx = (second.x_coord - tx)/tw
      rx = (second.y_coord - ty)/tw
      if sx == 0 then sx = 0.00001 end
    end
    if th ~= 0 then
      sy = (fourth.y_coord - ty)/th
      ry = (fourth.x_coord - tx)/th
      if sy == 0 then sy = 0.00001 end
    end

%    \end{macrocode}
% Attempt to address \#189, the displacement issue of pdf link boxes.
%    \begin{macrocode}
    local matrix = format("%f %f %f %f", sx, rx, ry, sy) :gsub(decimals,rmzeros)
    put2output("\\mplibputtextbox{%i}{%f}{%f}{%s}", n, tx, ty, matrix)
  end
end

%    \end{macrocode}
%
%    Colors
%    \begin{macrocode}
local do_preobj_CR
do
  local prev_override_color
  function do_preobj_CR(object,prescript)
    if object.postscript == "collect" then return end
    local override = prescript and prescript.mpliboverridecolor
    if override then
      if pdfmode then
        pdf_literalcode(override)
        override = nil
      else
        put2output("\\special{%s}",override)
        prev_override_color = override
      end
    else
      local cs = object.color
      if cs and #cs > 0 then
        pdf_literalcode(luamplib.colorconverter(cs))
        prev_override_color = nil
      elseif not pdfmode then
        override = prev_override_color
        if override then
          put2output("\\special{%s}",override)
        end
      end
    end
    return override
  end
end

%    \end{macrocode}
%
%    For transparency, shading, fading, and pattern
%    \begin{macrocode}
local pdfmanagement = is_defined'pdfmanagement_add:nnn'
local pdfobjs, pdfetcs = {}, {}
pdfetcs.pgfextgs = "pgf@sys@addpdfresource@extgs@plain"
pdfetcs.pgfpattern = "pgf@sys@addpdfresource@patterns@plain"
pdfetcs.pgfcolorspace = "pgf@sys@addpdfresource@colorspaces@plain"
local function update_pdfobjs (os, stream)
  local key = os
  if stream then key = key..stream end
  local on = key and pdfobjs[key]
  if on then
    return on,false
  end
  if pdfmode then
    if stream then
      on = pdf.immediateobj("stream",stream,os)
    elseif os then
      on = pdf.immediateobj(os)
    else
      on = pdf.reserveobj()
    end
  else
    on = pdfetcs.cnt or 1
    if stream then
      texsprint(format("\\special{pdf:stream @mplibpdfobj%s (%s) <<%s>>}",on,stream,os))
    elseif os then
      texsprint(format("\\special{pdf:obj @mplibpdfobj%s %s}",on,os))
    else
      texsprint(format("\\special{pdf:obj @mplibpdfobj%s <<>>}",on))
    end
    pdfetcs.cnt = on + 1
  end
  if key then
    pdfobjs[key] = on
  end
  return on,true
end
pdfetcs.resfmt = pdfmode and "%s 0 R" or "@mplibpdfobj%s"
if pdfmode then
  pdfetcs.getpageres = pdf.getpageresources or function() return pdf.pageresources end
  local getpageres = pdfetcs.getpageres
  local setpageres = pdf.setpageresources or function(s) pdf.pageresources = s end
  local initialize_resources = function (name)
    local tabname = format("%s_res",name)
    pdfetcs[tabname] = { }
    if luatexbase.callbacktypes.finish_pdffile then -- ltluatex
      local obj = pdf.reserveobj()
      setpageres(format("%s/%s %i 0 R", getpageres() or "", name, obj))
      luatexbase.add_to_callback("finish_pdffile", function()
        pdf.immediateobj(obj, format("<<%s>>", tableconcat(pdfetcs[tabname])))
      end,
      format("luamplib.%s.finish_pdffile",name))
    end
  end
  pdfetcs.fallback_update_resources = function (name, res)
    local tabname = format("%s_res",name)
    if not pdfetcs[tabname] then
      initialize_resources(name)
    end
    if luatexbase.callbacktypes.finish_pdffile then
      local t = pdfetcs[tabname]
      t[#t+1] = res
    else
      local tpr, n = getpageres() or "", 0
      tpr, n = tpr:gsub(format("/%s<<",name), "%1"..res)
      if n == 0 then
        tpr = format("%s/%s<<%s>>", tpr, name, res)
      end
      setpageres(tpr)
    end
  end
else
  texsprint {
    "\\luamplibatfirstshipout{",
    "\\special{pdf:obj @MPlibTr<<>>}",
    "\\special{pdf:obj @MPlibSh<<>>}",
    "\\special{pdf:obj @MPlibCS<<>>}",
    "\\special{pdf:obj @MPlibPt<<>>}}",
  }
  pdfetcs.fallback_update_resources = function (name,res,obj)
    texsprint{"\\special{pdf:put ", obj, " <<", res, ">>}"}
    local tabname = format("%s_res",name)
    if not pdfetcs[tabname] then
      texsprint{"\\luamplibateveryshipout{\\special{pdf:put @resources <</", name, " ", obj, ">>}}"}
      pdfetcs[tabname] = { }
    end
    tableinsert(pdfetcs[tabname], res)
  end
end

%    \end{macrocode}
%
%    Transparency
%    \begin{macrocode}
local function add_extgs_resources (on, new)
  local key = format("MPlibTr%s", on)
  if new then
    local val = format(pdfetcs.resfmt, on)
    if pdfmanagement then
      texsprint {
        "\\csname pdfmanagement_add:nnn\\endcsname{Page/Resources/ExtGState}{", key, "}{", val, "}"
      }
    else
      local tr = format("/%s %s", key, val)
      if is_defined(pdfetcs.pgfextgs) then
        texsprint { "\\csname ", pdfetcs.pgfextgs, "\\endcsname{", tr, "}" }
      elseif is_defined"TRP@list" then
        texsprint(catat11,{
          [[\if@filesw\immediate\write\@auxout{]],
          [[\string\g@addto@macro\string\TRP@list{]],
          tr,
          [[}}\fi]],
        })
        if not get_macro"TRP@list":find(tr) then
          texsprint(catat11,[[\global\TRP@reruntrue]])
        end
      else
        pdfetcs.fallback_update_resources("ExtGState",tr,"@MPlibTr")
      end
    end
  end
  return key
end

local do_preobj_TR
do
  local transparancy_modes = {
    [0] = "Normal",
    "Normal",       "Multiply",     "Screen",       "Overlay",
    "SoftLight",    "HardLight",    "ColorDodge",   "ColorBurn",
    "Darken",       "Lighten",      "Difference",   "Exclusion",
    "Hue",          "Saturation",   "Color",        "Luminosity",
    "Compatible",
    normal     = "Normal",     multiply   = "Multiply",   screen    = "Screen",
    overlay    = "Overlay",    softlight  = "SoftLight",  hardlight = "HardLight",
    colordodge = "ColorDodge", colorburn  = "ColorBurn",  darken    = "Darken",
    lighten    = "Lighten",    difference = "Difference", exclusion = "Exclusion",
    hue        = "Hue",        saturation = "Saturation", color     = "Color",
    luminosity = "Luminosity", compatible = "Compatible",
  }
  function do_preobj_TR(object,prescript)
    if object.postscript == "collect" then return end
    local opaq = prescript and prescript.tr_transparency
    if not opaq then return end

    local key, on, os, new
    local mode = prescript.tr_alternative or 1
    mode = transparancy_modes[tonumber(mode) or mode:lower()]
    if not mode then
      mode = prescript.tr_alternative
      warn("unsupported blend mode: '%s'", mode)
    end
    opaq = opaq:explode":"
    for i,v in ipairs(opaq) do
      opaq[i] = format("%.3f", v) :gsub(decimals,rmzeros)
    end
    for i,v in ipairs{ {mode,opaq[1],opaq[2] or opaq[1]},{"Normal",1,1} } do
      os = format("<</BM/%s/ca %s/CA %s/AIS false>>",v[1],v[2],v[3])
      on, new = update_pdfobjs(os)
      key = add_extgs_resources(on,new)
      if i == 1 then
        pdf_literalcode("/%s gs",key)
      else
        return format("/%s gs",key)
      end
    end
  end
end

%    \end{macrocode}
%
%    Shading with \emph{metafun} format.
%    \begin{macrocode}
local function sh_pdfpageresources(shtype,domain,colorspace,ca,cb,coordinates,steps,fractions,extend)
  for _,v in ipairs{ca,cb} do
    for i,vv in ipairs(v) do
      for ii,vvv in ipairs(vv) do
        v[i][ii] = tonumber(vvv) and format("%.3f",vvv) or vvv
      end
    end
  end
  local fun2fmt,os = "<</FunctionType 2/Domain[%s]/C0[%s]/C1[%s]/N 1>>"
  if steps > 1 then
    local list,bounds,encode = { },{ },{ }
    for i=1,steps do
      if i < steps then
        bounds[i] = format("%.3f", fractions[i] or 1)
      end
      encode[2*i-1] = 0
      encode[2*i]   = 1
      os = fun2fmt:format(domain,tableconcat(ca[i],' '),tableconcat(cb[i],' '))
        :gsub(decimals,rmzeros)
      list[i] = format(pdfetcs.resfmt, update_pdfobjs(os))
    end
    os = tableconcat {
      "<</FunctionType 3",
      format("/Bounds[%s]",    tableconcat(bounds,' ')),
      format("/Encode[%s]",    tableconcat(encode,' ')),
      format("/Functions[%s]", tableconcat(list,  ' ')),
      format("/Domain[%s]>>",  domain),
    } :gsub(decimals,rmzeros)
  else
    os = fun2fmt:format(domain,tableconcat(ca[1],' '),tableconcat(cb[1],' '))
      :gsub(decimals,rmzeros)
  end
  local objref = format(pdfetcs.resfmt, update_pdfobjs(os))
  os = tableconcat {
    format("<</ShadingType %i", shtype),
    format("/ColorSpace %s",    colorspace),
    format("/Function %s",      objref),
    format("/Coords[%s]",       coordinates),
    format("/Extend[%s]/AntiAlias true>>", extend or "true true")
  } :gsub(decimals,rmzeros)
  local on, new = update_pdfobjs(os)
  if new then
    local key, val = format("MPlibSh%s", on), format(pdfetcs.resfmt, on)
    if pdfmanagement then
      texsprint {
        "\\csname pdfmanagement_add:nnn\\endcsname{Page/Resources/Shading}{", key, "}{", val, "}"
      }
    else
      local res = format("/%s %s", key, val)
      pdfetcs.fallback_update_resources("Shading",res,"@MPlibSh")
    end
  end
  return on
end

local do_preobj_SH
do
  pdfetcs.clrspcs = setmetatable({ }, { __index = function(t,names)
    run_tex_code({
      [[\color_model_new:nnn]],
      format("{mplibcolorspace_%s}", names:gsub(",","_")),
      format("{DeviceN}{names={%s}}", names),
      [[\edef\mplib_@tempa{\pdf_object_ref_last:}]],
    }, ccexplat)
    local colorspace = get_macro'mplib_@tempa'
    t[names] = colorspace
    return colorspace
  end })
  local function color_normalize(ca,cb)
    if #cb == 1 then
      if #ca == 4 then
        cb[1], cb[2], cb[3], cb[4] = 0, 0, 0, 1-cb[1]
      else -- #ca = 3
        cb[1], cb[2], cb[3] = cb[1], cb[1], cb[1]
      end
    elseif #cb == 3 then -- #ca == 4
      cb[1], cb[2], cb[3], cb[4] = 1-cb[1], 1-cb[2], 1-cb[3], 0
    end
  end
  function do_preobj_SH(object, prescript)
    local shade_no
    local sh_type = prescript and prescript.sh_type
    if not sh_type then return end

    local domain  = prescript.sh_domain or "0 1"
    local centera = (prescript.sh_center_a or "0 0"):explode()
    local centerb = (prescript.sh_center_b or "0 0"):explode()
    local transform = prescript.sh_transform == "yes"
    local sx,sy,sr,dx,dy = 1,1,1,0,0
    if transform then
      local first = (prescript.sh_first or "0 0"):explode()
      local setx  = (prescript.sh_set_x or "0 0"):explode()
      local sety  = (prescript.sh_set_y or "0 0"):explode()
      local x,y = tonumber(setx[1]) or 0, tonumber(sety[1]) or 0
      if x ~= 0 and y ~= 0 then
        local path = object.path
        local path1x = path[1].x_coord
        local path1y = path[1].y_coord
        local path2x = path[x].x_coord
        local path2y = path[y].y_coord
        local dxa = path2x - path1x
        local dya = path2y - path1y
        local dxb = setx[2] - first[1]
        local dyb = sety[2] - first[2]
        if dxa ~= 0 and dya ~= 0 and dxb ~= 0 and dyb ~= 0 then
          sx = dxa / dxb ; if sx < 0 then sx = - sx end
          sy = dya / dyb ; if sy < 0 then sy = - sy end
          sr = math.sqrt(sx^2 + sy^2)
          dx = path1x - sx*first[1]
          dy = path1y - sy*first[2]
        end
      end
    end
    local ca, cb, colorspace, steps, fractions
    ca = { (prescript.sh_color_a_1 or prescript.sh_color_a or "0"):explode":" }
    cb = { (prescript.sh_color_b_1 or prescript.sh_color_b or "1"):explode":" }
    steps = tonumber(prescript.sh_step) or 1
    if steps > 1 then
      fractions = { prescript.sh_fraction_1 or 0 }
      for i=2,steps do
        fractions[i] = prescript[format("sh_fraction_%i",i)] or (i/steps)
        ca[i] = (prescript[format("sh_color_a_%i",i)] or "0"):explode":"
        cb[i] = (prescript[format("sh_color_b_%i",i)] or "1"):explode":"
      end
    end
    if prescript.mplib_spotcolor then
      ca, cb = { }, { }
      local names, pos, objref = { }, -1, ""
      local script = object.prescript:explode"\13+"
      for i=#script,1,-1 do
        if script[i]:find"mplib_spotcolor" then
          local t, name, value = script[i]:explode"="[2]:explode":"
          value, objref, name = t[1], t[2], t[3]
          if not names[name] then
            pos = pos+1
            names[name] = pos
            names[#names+1] = name
          end
          t = { }
          for j=1,names[name] do t[#t+1] = 0 end
          t[#t+1] = value
          tableinsert(#ca == #cb and ca or cb, t)
        end
      end
      for _,t in ipairs{ca,cb} do
        for _,tt in ipairs(t) do
          for i=1,#names-#tt do tt[#tt+1] = 0 end
        end
      end
      if #names == 1 then
        colorspace = objref
      else
        colorspace = pdfetcs.clrspcs[ tableconcat(names,",") ]
      end
    else
      local model = 0
      for _,t in ipairs{ca,cb} do
        for _,tt in ipairs(t) do
          model = model > #tt and model or #tt
        end
      end
      for _,t in ipairs{ca,cb} do
        for _,tt in ipairs(t) do
          if #tt < model then
            color_normalize(model == 4 and {1,1,1,1} or {1,1,1},tt)
          end
        end
      end
      colorspace = model == 4 and "/DeviceCMYK"
                or model == 3 and "/DeviceRGB"
                or model == 1 and "/DeviceGray"
                or err"unknown color model"
    end
    local extend = prescript.sh_extend
    if sh_type == "linear" then
      local coordinates = format("%f %f %f %f",
        dx + sx*centera[1], dy + sy*centera[2],
        dx + sx*centerb[1], dy + sy*centerb[2])
      shade_no = sh_pdfpageresources(2,domain,colorspace,ca,cb,coordinates,steps,fractions,extend)
    elseif sh_type == "circular" then
      local factor = prescript.sh_factor or 1
      local radiusa = factor * prescript.sh_radius_a
      local radiusb = factor * prescript.sh_radius_b
      local coordinates = format("%f %f %f %f %f %f",
        dx + sx*centera[1], dy + sy*centera[2], sr*radiusa,
        dx + sx*centerb[1], dy + sy*centerb[2], sr*radiusb)
      shade_no = sh_pdfpageresources(3,domain,colorspace,ca,cb,coordinates,steps,fractions,extend)
    else
      err"unknown shading type"
    end
    return shade_no, prescript.sh_stroking == "yes"
  end
end

%    \end{macrocode}
%
% Shading Patterns:
% we can apply shading to textual pictures as well as paths.
%    \begin{macrocode}
local function add_pattern_resources (key, val)
  if pdfmanagement then
    texsprint {
      "\\csname pdfmanagement_add:nnn\\endcsname{Page/Resources/Pattern}{", key, "}{", val, "}"
    }
  else
    local res = format("/%s %s", key, val)
    if is_defined(pdfetcs.pgfpattern) then
      texsprint { "\\csname ", pdfetcs.pgfpattern, "\\endcsname{", res, "}" }
    else
      pdfetcs.fallback_update_resources("Pattern",res,"@MPlibPt")
    end
  end
end
if pdfmode then
  function luamplib.dolatelua (on, os, matrix)
    local h, v = pdf.getpos()
    local t = matrix and matrix:explode() or {1,0,0,1,0,0}
    matrix = format("%f %f %f %f %f %f", t[1], t[2], t[3], t[4], t[5]+h/factor, t[6]+v/factor)
      :gsub(decimals,rmzeros)
    pdf.obj(on, format("<<%s/Matrix[%s]>>", os, matrix))
    pdf.refobj(on)
  end
else
  pdfetcs.shadingpatterns = { }
  pdfetcs.shadingpatterninit_r, pdfetcs.shadingpatterninit_w = true, true
  function luamplib.dolatelua (on, kind, xobj)
    local h, v
    local t = pdfetcs.shadingpatterns[on] or { }
    local shift = kind == "group" and pdfetcs.tr_group.shifts[xobj]
               or kind == "pattern" and pdfetcs.patterns[xobj].shifts
    if shift then
      h, v = -shift[1], -shift[2] -- engine bug in dvi mode?
    else
      h, v = pdf.getpos()
      h = format("%f", h/factor) :gsub(decimals,rmzeros)
      v = format("%f", v/factor) :gsub(decimals,rmzeros)
    end
    if tonumber(h) ~= tonumber(t[1]) or tonumber(v) ~= tonumber(t[2]) then
      warn"Rerun to get correct shading pattern"
    end
    local name = format("%s/%s_shadingpatterns.aux", cachedir or outputdir(), tex.jobname)
    local init = pdfetcs.shadingpatterninit_w
    if init then pdfetcs.shadingpatterninit_w = nil end
    local f = ioopen(name, init and "w" or "a")
    if f then
      f:write(("%s %s %s\n"):format(on, h, v))
      f:close()
    else
      err"cannot write a file. check the cache dir path"
    end
  end
end
local function do_preobj_shading (object, prescript)
  if not prescript or not prescript.sh_operand_type then return end
  local on = do_preobj_SH(object, prescript)
  local os = format("/PatternType 2/Shading %s", format(pdfetcs.resfmt, on))
  local matrix = prescript.sh_matrix or "1 0 0 1 0 0"
  if matrix:find"%a" then
    local data = format("mplibtransformmatrix(%s);",matrix)
    process(data,"@mplibtransformmatrix")
    local t = luamplib.transformmatrix
    matrix = format("%f %f %f %f %f %f", t[1], t[2], t[3], t[4], t[5], t[6]):gsub(decimals,rmzeros)
  end
  if prescript.sh_in_xobj == "yes" then
    on = update_pdfobjs(("<<%s/Matrix[%s]>>"):format(os, matrix))
    goto skip_latelua
  end
  on = update_pdfobjs()
  if pdfmode then
    put2output(tableconcat{"\\latelua{luamplib.dolatelua(",on,",[[",os,"]],[[",matrix,"]])}"})
  else
    local xobj = is_defined"mplibgroupname" and {"group", get_macro"mplibgroupname"}
              or is_defined"mplibpatternname" and {"pattern", get_macro"mplibpatternname"}
    local init = pdfetcs.shadingpatterninit_r
    if init then
      pdfetcs.shadingpatterninit_r = nil
      local name = format("%s/%s_shadingpatterns.aux", cachedir or outputdir(), tex.jobname)
      local f = ioopen(name)
      if f then
        for line in f:lines() do
          local t = line:explode()
          pdfetcs.shadingpatterns[ tonumber(t[1]) ] = { t[2], t[3] }
        end
        f:close()
      end
    end
%    \end{macrocode}
% This seems to be needed for proper functioning:
%\begin{verbatim}
%    \pagewidth=\paperwidth
%    \pageheight=\paperheight
%    \special{papersize=\the\paperwidth,\the\paperheight}
%\end{verbatim}
%    \begin{macrocode}
    local t = pdfetcs.shadingpatterns[on] or { 0, 0 }
    local mt = matrix:explode()
    matrix = format("%s %s %s %s %s %s", mt[1], mt[2], mt[3], mt[4], mt[5]+t[1], mt[6]+t[2])
    texsprint{ "\\special{pdf:put ", format(pdfetcs.resfmt, on),
              format(" <<%s/Matrix[%s]>>}", os, matrix) }
    put2output("\\latelua{ luamplib.dolatelua(%s,%s) }", on,
              xobj and ("'%s',[[%s]]"):format(xobj[1], xobj[2]))
  end
  ::skip_latelua::
  local key, val = format("MPlibPt%s", on), format(pdfetcs.resfmt, on)
  add_pattern_resources(key,val)
  pdf_literalcode("/Pattern cs/%s scn", key)
%    \end{macrocode}
% To avoid possible double execution, once by Pattern gs, once by Sh operator.
%    \begin{macrocode}
  prescript.sh_type = nil
end

%    \end{macrocode}
%
%    Tiling Patterns
%    \begin{macrocode}
pdfetcs.patterns = { }
local function gather_resources (optres, ispattern)
  local t = { }
  if pdfmanagement then
    for _,v in ipairs {"ExtGState","ColorSpace","Pattern","Shading"} do
      local mytoks
      run_tex_code ({
        "\\mplibtmptoks\\expanded{{",
        "\\pdfdict_if_empty:nF{g__pdf_Core/Page/Resources/",v,"}",
        "{\\pdfdict_use:n{g__pdf_Core/Page/Resources/",v,"}}", "}}",
      },ccexplat)
      mytoks = texgettoks"mplibtmptoks"
      if not pdfmode then
        mytoks = mytoks:gsub("\\str_convert_pdfname:n%s*{(.-)}","%1") -- why not expanded?
      end
      mytoks = mytoks and mytoks:gsub("^%s*(.-)%s*$", "%1")
      if mytoks and mytoks ~= "" then
        t[#t+1] = ("/%s<<%s>>"):format(v, mytoks)
      end
    end
  elseif is_defined(pdfetcs.pgfextgs) then
    run_tex_code"\\relax" -- flush tex.sprint queue
    if pdfmode then
      for k,v in pairs { ExtGState  = "pgf@sys@pgf@resource@list@extgs",
                         ColorSpace = "pgf@sys@pgf@resource@list@colorspaces",
                         Pattern    = "pgf@sys@pgf@resource@list@patterns", } do
        local res = (get_macro(v) or ""):gsub("^%s*(.-)%s*$","%1")
        if res ~= "" then
          t[#t+1] = ("/%s<<%s>>"):format(k, res )
        end
      end
    else
      local abc = get_macro"pgfutil@abc" or ""
      for k,v in pairs { ExtGState  = "@pgfextgs",
                         ColorSpace = "@pgfcolorspaces",
                         Pattern    = "@pgfpatterns", } do
        local tt = { }
        for vv in abc:gmatch( v .. "%s*(%b<>)" ) do
          tt[#tt+1] = vv:match("^<<%s*(.-)%s*>>$")
        end
        if #tt > 0 then
          t[#t+1] = ("/%s<<%s>>"):format(k, tableconcat(tt) )
        end
      end
    end
%    \end{macrocode}
% We still have to deal with Shading resources.
%    \begin{macrocode}
    if luatexbase.callbacktypes.finish_pdffile then
      if pdfetcs.Shading_res then
        t[#t+1] = ("/Shading<<%s>>"):format( tableconcat(pdfetcs.Shading_res) )
      end
    else
      local res = pdfetcs.getpageres()
      res = res and res:match"/Shading%s*%b<>"
      if res then
        t[#t+1] = res
      end
    end
  else
    if ispattern and is_defined"TRP@list" then
%    \end{macrocode}
% We do not gather \pkg{transparent} package's \cs{TRP@list}
% as Acrobat glitches on tiling pattern plus masking group,
% so warn users and recommend \cs{DocumentMetadata}
%    \begin{macrocode}
      warn"transparent package is not fully functional without pdfmanagement code."
    end
    if luatexbase.callbacktypes.finish_pdffile then
      for _,v in ipairs {"ExtGState","ColorSpace","Pattern","Shading"} do
        local tt = pdfetcs[v.."_res"]
        if tt then
          t[#t+1] = ("/%s<<%s>>"):format(v, tableconcat(tt))
        end
      end
    else
      local res = pdfetcs.getpageres()
      if res then
        t[#t+1] = res
      end
    end
  end
  local result = tableconcat(t)
  if optres ~= "" then
    for _,v in ipairs {"ExtGState","ColorSpace","Pattern","Shading"} do
      local res = optres:match("/"..v.."%s*%b<>")
      if res then
        if result:find("/"..v) then
          res = res:match("<<(.+)>>$")
          result = result:gsub("/"..v.."%s*<<", "%1"..res, 1)
        else
          result = result .. res
        end
      end
    end
  end
  return result
end
function luamplib.registerpattern ( boxid, name, opts )
  local box = texgetbox(boxid)
  local wd = format("%.3f",box.width/factor)
  local hd = format("%.3f",(box.height+box.depth)/factor)
  info("w/h/d of pattern '%s': %s 0", name, format("%s %s",wd, hd):gsub(decimals,rmzeros))
  if opts.xstep == 0 then opts.xstep = nil end
  if opts.ystep == 0 then opts.ystep = nil end
  if opts.colored == nil then
    opts.colored = opts.coloured
    if opts.colored == nil then
      opts.colored = true
    end
  end
  if type(opts.matrix) == "table" then opts.matrix = tableconcat(opts.matrix," ") end
  if type(opts.bbox) == "table" then opts.bbox = tableconcat(opts.bbox," ") end
  if opts.matrix and opts.matrix:find"%a" then
    local data = format("mplibtransformmatrix(%s);",opts.matrix)
    process(data,"@mplibtransformmatrix")
    local t = luamplib.transformmatrix
    opts.matrix = format("%f %f %f %f", t[1], t[2], t[3], t[4])
    opts.xshift = opts.xshift or format("%f",t[5])
    opts.yshift = opts.yshift or format("%f",t[6])
  end
  local attr = {
    "/Type/Pattern",
    "/PatternType 1",
    format("/PaintType %i", opts.colored and 1 or 2),
    "/TilingType 2",
    format("/XStep %s", opts.xstep or wd),
    format("/YStep %s", opts.ystep or hd),
    format("/Matrix[%s %s %s]", opts.matrix or "1 0 0 1", opts.xshift or 0, opts.yshift or 0),
  }
  local optres = opts.resources or ""
  optres = gather_resources(optres, true) -- tiling pattern plus masking glitches with acrobat
  local patterns = pdfetcs.patterns
  if pdfmode then
    if opts.bbox then
      attr[#attr+1] = format("/BBox[%s]", opts.bbox)
    end
    attr = tableconcat(attr) :gsub(decimals,rmzeros)
    local index = tex.saveboxresource(boxid, attr, optres, true, opts.bbox and 4 or 1)
    patterns[name] = { id = index, colored = opts.colored }
  else
    local cnt = #patterns + 1
    local objname = "@mplibpattern" .. cnt
    local metric = format("bbox %s", opts.bbox or format("0 0 %s %s",wd,hd))
    texsprint {
      "\\expandafter\\newbox\\csname luamplib.patternbox.", cnt, "\\endcsname",
      "\\global\\setbox\\csname luamplib.patternbox.", cnt, "\\endcsname",
      "\\hbox{\\unhbox ", boxid, "}\\luamplibatnextshipout{",
      "\\special{pdf:bcontent}",
      "\\special{pdf:bxobj ", objname, " ", metric, "}",
      "\\raise\\dp\\csname luamplib.patternbox.", cnt, "\\endcsname",
      "\\box\\csname luamplib.patternbox.", cnt, "\\endcsname",
      "\\special{pdf:put @resources <<", optres, ">>}",
      "\\special{pdf:exobj <<", tableconcat(attr), ">>}",
      "\\special{pdf:econtent}}",
    }
    patterns[cnt] = objname
    patterns[name] = { id = cnt, colored = opts.colored }
    patterns[name].shifts = { get_macro"MPllx", get_macro"MPlly" } -- for shading patterns above
  end
end

local do_preobj_PAT
do
  local function pattern_colorspace (cs)
    local on, new = update_pdfobjs(format("[/Pattern %s]", cs))
    if new then
      local key, val = format("MPlibCS%i",on), format(pdfetcs.resfmt,on)
      if pdfmanagement then
        texsprint {
          "\\csname pdfmanagement_add:nnn\\endcsname{Page/Resources/ColorSpace}{", key, "}{", val, "}"
        }
      else
        local res = format("/%s %s", key, val)
        if is_defined(pdfetcs.pgfcolorspace) then
          texsprint { "\\csname ", pdfetcs.pgfcolorspace, "\\endcsname{", res, "}" }
        else
          pdfetcs.fallback_update_resources("ColorSpace",res,"@MPlibCS")
        end
      end
    end
    return on
  end
  function do_preobj_PAT(object, prescript)
    local name = prescript and prescript.mplibpattern
    if not name then return end
    local patterns = pdfetcs.patterns
    local patt = patterns[name]
    local index = patt and patt.id or err("cannot get pattern object '%s'", name)
    local key = format("MPlibPt%s",index)
    if patt.colored then
      pdf_literalcode("/Pattern cs /%s scn", key)
    else
      local color = prescript.mpliboverridecolor
      if not color then
        local t = object.color
        color = t and #t>0 and luamplib.colorconverter(t)
      end
      if not color then return end
      local cs
      if color:find" cs " or color:find"@pdf.obj" then
        local t = color:explode()
        if pdfmode then
          cs = format("%s 0 R", ltx.pdf.object_id( t[1]:sub(2,-1) ))
          color = t[3]
        else
          cs = t[2]
          color = t[3]:match"%[(.+)%]"
        end
      else
        local t = colorsplit(color)
        cs = #t == 4 and "/DeviceCMYK" or #t == 3 and "/DeviceRGB" or "/DeviceGray"
        color = tableconcat(t," ")
      end
      pdf_literalcode("/MPlibCS%i cs %s /%s scn", pattern_colorspace(cs), color, key)
    end
    if not patt.done then
      local val = pdfmode and format("%s 0 R",index) or patterns[index]
      add_pattern_resources(key,val)
    end
    patt.done = true
  end
end

%    \end{macrocode}
%
%    Fading
%    \begin{macrocode}
pdfetcs.fading = { }
local function do_preobj_FADE (object, prescript)
  local fd_type = prescript and prescript.mplibfadetype
  local fd_stop = prescript and prescript.mplibfadestate
  if not fd_type then
    return fd_stop -- returns "stop" (if picture) or nil
  end
  local on, os, new
  if fd_type == "masking" then
    local mac = get_macro("luamplib.group."..prescript.mplibmaskname)
    on = mac:match(pdfmode and "%d+" or "{pdf:uxobj (.-)}")
    local bc = prescript.mplibmaskingbgcolor
    bc = bc and bc:gsub(":"," ")
    bc = bc and ("/BC[%s]"):format(bc):gsub(decimals,rmzeros) or ""
    os = format("<</SMask<</S/Luminosity/G %s%s>>>>",
                pdfmode and format(pdfetcs.resfmt, on) or on, bc)
  else
    local bbox = prescript.mplibfadebbox:explode":"
    local dx, dy = -bbox[1], -bbox[2]
    local vec = prescript.mplibfadevector; vec = vec and vec:explode":"
    if not vec then
      if fd_type == "linear" then
        vec = {bbox[1], bbox[2], bbox[3], bbox[2]} -- left to right
      else
        local centerx, centery = (bbox[1]+bbox[3])/2, (bbox[2]+bbox[4])/2
        vec = {centerx, centery, centerx, centery} -- center for both circles
      end
    end
    local coords = { vec[1], vec[2], vec[3], vec[4] }
    if fd_type == "linear" then
      coords = format("%f %f %f %f", tableunpack(coords))
    elseif fd_type == "circular" then
      local width, height = bbox[3]-bbox[1], bbox[4]-bbox[2]
      local radius = (prescript.mplibfaderadius or "0:"..math.sqrt(width^2+height^2)/2):explode":"
      tableinsert(coords, 3, radius[1])
      tableinsert(coords, radius[2])
      coords = format("%f %f %f %f %f %f", tableunpack(coords))
    else
      err("unknown fading method '%s'", fd_type)
    end
    fd_type = fd_type == "linear" and 2 or 3
    local extend, steps, fractions = prescript.sh_extend, tonumber(prescript.sh_step) or 1
    local ca = { (prescript.sh_color_a_1 or prescript.sh_color_a or "1"):explode":" }
    local cb = { (prescript.sh_color_b_1 or prescript.sh_color_b or "0"):explode":" }
    if steps > 1 then
      fractions = { prescript.sh_fraction_1 or 0 }
      for i=2,steps do
        fractions[i] = prescript[format("sh_fraction_%i",i)] or (i/steps)
        ca[i] = (prescript[format("sh_color_a_%i",i)] or "1"):explode":"
        cb[i] = (prescript[format("sh_color_b_%i",i)] or "0"):explode":"
      end
    end
    local matrix = prescript.sh_matrix or "1 0 0 1 0 0"
    if matrix:find"%a" then
      local data = format("mplibtransformmatrix(%s);",matrix)
      process(data,"@mplibtransformmatrix")
      matrix = luamplib.transformmatrix
    else
      matrix = matrix:explode()
    end
    matrix[5] = matrix[5] + dx
    matrix[6] = matrix[6] + dy
    matrix = format("%f %f %f %f %f %f", tableunpack(matrix)) :gsub(decimals,rmzeros)
    on = sh_pdfpageresources(fd_type,"0 1","/DeviceGray",ca,cb,coords,steps,fractions,extend)
    os = format("<</PatternType 2/Shading %s/Matrix[%s]>>", format(pdfetcs.resfmt, on), matrix)
    on = update_pdfobjs(os)
    bbox = format("0 0 %f %f", bbox[3]+dx, bbox[4]+dy)
    local streamtext = format("q /Pattern cs/MPlibFd%s scn %s re f Q", on, bbox)
      :gsub(decimals,rmzeros)
    os = format("<</Pattern<</MPlibFd%s %s>>>>", on, format(pdfetcs.resfmt, on))
    on = update_pdfobjs(os)
    local resources = format(pdfetcs.resfmt, on)
    on = update_pdfobjs"<</S/Transparency/CS/DeviceGray>>"
    local attr = tableconcat{
      "/Subtype/Form",
      "/BBox[", bbox, "]",
      "/Matrix[1 0 0 1 ", format("%f %f", -dx,-dy), "]",
      "/Resources ", resources,
      "/Group ", format(pdfetcs.resfmt, on),
    } :gsub(decimals,rmzeros)
    on = update_pdfobjs(attr, streamtext)
    os = format("<</SMask<</S/Luminosity/G %s>>>>", format(pdfetcs.resfmt, on))
  end
  on, new = update_pdfobjs(os)
  local key = add_extgs_resources(on,new)
  start_pdf_code()
  pdf_literalcode("/%s gs", key)
  if fd_stop then return "standalone" end
  return "start"
end

%    \end{macrocode}
%
%    Transparency Group
%    \begin{macrocode}
pdfetcs.tr_group = { shifts = { } }
luamplib.trgroupshifts = pdfetcs.tr_group.shifts
local function do_preobj_GRP (object, prescript)
  local grstate = prescript and prescript.gr_state
  if not grstate then return end
  local trgroup = pdfetcs.tr_group
  if grstate == "start" then
    trgroup.name = prescript.mplibgroupname or "lastmplibgroup"
    trgroup.isolated, trgroup.knockout, trgroup.off = false, false, false
    trgroup.wrapped = false
    for _,v in ipairs(prescript.gr_type:gsub("%s",""):explode",+") do
      trgroup[v] = true
    end
    trgroup.bbox = prescript.mplibgroupbbox:explode":"
    put2output[[\begingroup\setbox\mplibscratchbox\hbox\bgroup\luamplibtagasgroupset]]
  elseif grstate == "stop" then
    local llx,lly,urx,ury = tableunpack(trgroup.bbox)
    put2output(tableconcat{
      "\\egroup",
      format("\\wd\\mplibscratchbox %fbp", urx-llx),
      format("\\ht\\mplibscratchbox %fbp", ury-lly),
      "\\dp\\mplibscratchbox 0pt",
    })
    local grattr
    if trgroup.off then
      grattr = ""
    else
      local on = update_pdfobjs(format("<</S/Transparency/I %s/K %s>>",
                                       trgroup.isolated, trgroup.knockout))
      grattr = format("/Group %s", pdfetcs.resfmt:format(on))
    end
    local res = gather_resources("")
    local bbox = format("%f %f %f %f", llx,lly,urx,ury) :gsub(decimals,rmzeros)
    if pdfmode then
      if trgroup.wrapped then
        put2output(tableconcat{
          "\\saveboxresource type 2 attr{/Type/XObject/Subtype/Form/FormType 1",
          "/BBox[", bbox, "]} resources{", res, "}\\mplibscratchbox",
          "\\setbox\\mplibscratchbox\\hbox{\\useboxresource\\lastsavedboxresourceindex}",
        })
      end
      put2output(tableconcat{
        "\\saveboxresource type 2 attr{/Type/XObject/Subtype/Form/FormType 1",
        "/BBox[", bbox, "]", grattr, "} resources{", res, "}\\mplibscratchbox",
        "\\luamplibtagasgroupput{",trgroup.name,"}{",
        [[\setbox\mplibscratchbox\hbox{\useboxresource\lastsavedboxresourceindex}]],
        [[\wd\mplibscratchbox 0pt\ht\mplibscratchbox 0pt\dp\mplibscratchbox 0pt]],
        [[\box\mplibscratchbox]],
        "}\\endgroup",
        "\\expandafter\\xdef\\csname luamplib.group.", trgroup.name, "\\endcsname{",
        "\\setbox\\mplibscratchbox\\hbox{\\hskip",-llx,"bp\\raise",-lly,"bp\\hbox{",
        "\\useboxresource \\the\\lastsavedboxresourceindex",
        "}}\\wd\\mplibscratchbox",urx-llx,"bp\\ht\\mplibscratchbox",ury-lly,"bp",
        "\\box\\mplibscratchbox}",
      })
    else
      if trgroup.wrapped then
        trgroup.cnt = (trgroup.cnt or 0) + 1
        local objname = format("@mplibtrgr%s", trgroup.cnt)
        put2output(tableconcat{
          "\\special{pdf:bxobj ", objname, " bbox ", bbox, "}",
          "\\unhbox\\mplibscratchbox",
          "\\special{pdf:put @resources <<", res, ">>}",
          "\\special{pdf:exobj}",
          "\\setbox\\mplibscratchbox\\hbox{\\special{pdf:uxobj ", objname, "}}",
        })
      end
      trgroup.cnt = (trgroup.cnt or 0) + 1
      local objname = format("@mplibtrgr%s", trgroup.cnt)
      put2output(tableconcat{
        "\\special{pdf:bxobj ", objname, " bbox ", bbox, "}",
        "\\unhbox\\mplibscratchbox",
        "\\special{pdf:put @resources <<", res, ">>}",
        "\\special{pdf:exobj <<", grattr, ">>}",
        "\\luamplibtagasgroupput{",trgroup.name,"}{",
        "\\special{pdf:uxobj ", objname, "}",
        "}\\endgroup",
      })
      token.set_macro("luamplib.group."..trgroup.name, tableconcat{
        "\\setbox\\mplibscratchbox\\hbox{\\hskip",-llx,"bp\\raise",-lly,"bp\\hbox{",
        "\\special{pdf:uxobj ", objname, "}",
        "}}\\wd\\mplibscratchbox",urx-llx,"bp\\ht\\mplibscratchbox",ury-lly,"bp",
        "\\box\\mplibscratchbox",
      }, "global")
    end
    trgroup.shifts[trgroup.name] = { llx, lly }
  end
  return grstate
end
function luamplib.registergroup (boxid, name, opts)
  if opts.asgroup and opts.asgroup:find"wrapped" then
    luamplib.registergroup(boxid, name, {bbox=opts.bbox, resources=opts.resources})
    run_tex_code{"\\setbox", boxid, "\\hbox bdir0{\\csname luamplib.group.", name, "\\endcsname}"}
    opts.asgroup = opts.asgroup:gsub("wrapped","")
  end
  local box = texgetbox(boxid)
  local wd, ht, dp = node.getwhd(box)
  local is_mask = opts.asgroup and opts.asgroup:find"masking"
  local res = opts.resources or ""
  res = gather_resources(res)
  local attr = { "/Type/XObject/Subtype/Form/FormType 1" }
  if type(opts.matrix) == "table" then opts.matrix = tableconcat(opts.matrix," ") end
  if type(opts.bbox) == "table" then opts.bbox = tableconcat(opts.bbox," ") end
  if opts.matrix and opts.matrix:find"%a" then
    local data = format("mplibtransformmatrix(%s);",opts.matrix)
    process(data,"@mplibtransformmatrix")
    opts.matrix = format("%f %f %f %f %f %f",tableunpack(luamplib.transformmatrix))
  end
  local grtype = 3
  if opts.bbox then
    attr[#attr+1] = format("/BBox[%s]", opts.bbox)
    grtype = 2
  end
  local mpllx, mplly = get_macro'MPllx', get_macro'MPlly'
  if is_mask then
    local t = opts.matrix and opts.matrix:explode() or {1, 0, 0, 1, 0, 0}
    t[5], t[6] = t[5]+mpllx, t[6]+mplly
    opts.matrix = format("%f %f %f %f %f %f",tableunpack(t))
    mpllx, mplly = 0, 0
  end
  if opts.matrix then
    attr[#attr+1] = format("/Matrix[%s]", opts.matrix)
    grtype = opts.bbox and 4 or 1
  end
  if opts.asgroup and not opts.asgroup:find"off" then
    local t = { isolated = false, knockout = false, masking = false }
    for _,v in ipairs(opts.asgroup:gsub("%s",""):explode",+") do t[v] = true end
    local on
    if t.masking then
      on = update_pdfobjs(format("<</S/Transparency/CS%s>>", opts.colorspace or "/DeviceGray"))
    else
      local cs = opts.colorspace and ("/CS%s"):format(opts.colorspace) or ""
      on = update_pdfobjs(format("<</S/Transparency%s/I %s/K %s>>", cs, t.isolated, t.knockout))
    end
    attr[#attr+1] = format("/Group %s", pdfetcs.resfmt:format(on))
  end
  local trgroup = pdfetcs.tr_group
  trgroup.shifts[name] = { mpllx, mplly }
  local whd
  if pdfmode then
    attr = tableconcat(attr) :gsub(decimals,rmzeros)
    local index = tex.saveboxresource(boxid, attr, res, true, grtype)
    token.set_macro("luamplib.group."..name, tableconcat{
      "\\useboxresource ", index,
    }, "global")
    whd = format("%.3f %.3f 0", wd/factor, (ht+dp)/factor) :gsub(decimals,rmzeros)
  else
    trgroup.cnt = (trgroup.cnt or 0) + 1
    local objname = format("@mplibtrgr%s", trgroup.cnt)
    texsprint {
      "\\expandafter\\newbox\\csname luamplib.groupbox.", trgroup.cnt, "\\endcsname",
      "\\global\\setbox\\csname luamplib.groupbox.", trgroup.cnt, "\\endcsname",
      "\\hbox{\\unhbox ", boxid, "}\\luamplibatnextshipout{",
      "\\special{pdf:bcontent}",
      "\\special{pdf:bxobj ", objname, " width ", wd, "sp height ", ht, "sp depth ", dp, "sp}",
      "\\unhbox\\csname luamplib.groupbox.", trgroup.cnt, "\\endcsname",
      "\\special{pdf:put @resources <<", res, ">>}",
      "\\special{pdf:exobj <<", tableconcat(attr), ">>}",
      "\\special{pdf:econtent}}",
    }
    token.set_macro("luamplib.group."..name, tableconcat{
      "\\setbox\\mplibscratchbox\\hbox{\\special{pdf:uxobj ", objname, "}}",
      "\\wd\\mplibscratchbox ", wd, "sp",
      "\\ht\\mplibscratchbox ", ht, "sp",
      "\\dp\\mplibscratchbox ", dp, "sp",
      "\\box\\mplibscratchbox",
    }, "global")
    whd = format("%.3f %.3f %.3f", wd/factor, ht/factor, dp/factor) :gsub(decimals,rmzeros)
  end
  info("w/h/d of group '%s': %s", name, whd)
end

%    \end{macrocode}
%
%    |luamplib.convert|: flushing figures
%    \begin{macrocode}
do
  local function stop_special_effects(fade,opaq,over)
    if fade then -- fading
      stop_pdf_code()
    end
    if opaq then -- opacity
      pdf_literalcode(opaq)
    end
    if over then -- color
      if over:find"pdf:bc" then
        put2output"\\special{pdf:ec}"
      else
        put2output"\\special{color pop}"
      end
    end
  end

%    \end{macrocode}
%    For parsing |prescript| materials.
%    \begin{macrocode}
  local function script2table(s)
    local t = {}
    for _,i in ipairs(s:explode("\13+")) do
      local k,v = i:match("(.-)=(.*)") -- v may contain = or empty.
      if k and v and k ~= "" and not t[k] then
        t[k] = v
      end
    end
    return t
  end

%    \end{macrocode}
%    Codes below to insert PDF lieterals are mostly from \ConTeXt general,
%    with small changes when needed.
%    \begin{macrocode}
  local function pdf_textfigure(font,size,text,width,height,depth)
    text = text:gsub(".",function(c)
      return format("\\hbox{\\char%i}",string.byte(c)) -- kerning happens in metapost : false
    end)
    put2output("\\mplibtextext{%s}{%f}{%s}{%s}{%s}",font,size,text,0,0)
  end

  local bend_tolerance = 131/65536

  local rx, sx, sy, ry, tx, ty, divider = 1, 0, 0, 1, 0, 0, 1

  local function pen_characteristics(object)
    local t = mplib.pen_info(object)
    rx, ry, sx, sy, tx, ty = t.rx, t.ry, t.sx, t.sy, t.tx, t.ty
    divider = sx*sy - rx*ry
    return not (sx==1 and rx==0 and ry==0 and sy==1 and tx==0 and ty==0), t.width
  end

  local function concat(px, py) -- no tx, ty here
    return (sy*px-ry*py)/divider,(sx*py-rx*px)/divider
  end

  local function curved(ith,pth)
    local d = pth.left_x - ith.right_x
    if abs(ith.right_x - ith.x_coord - d) <= bend_tolerance and
       abs(pth.x_coord - pth.left_x - d) <= bend_tolerance then
      d = pth.left_y - ith.right_y
      if abs(ith.right_y - ith.y_coord - d) <= bend_tolerance and
         abs(pth.y_coord - pth.left_y - d) <= bend_tolerance then
        return false
      end
    end
    return true
  end

  local function flushnormalpath(path,open)
    local pth, ith
    for i=1,#path do
      pth = path[i]
      if not ith then
        pdf_literalcode("%f %f m",pth.x_coord,pth.y_coord)
      elseif curved(ith,pth) then
        pdf_literalcode("%f %f %f %f %f %f c",
          ith.right_x,ith.right_y,pth.left_x,pth.left_y,pth.x_coord,pth.y_coord)
      else
        pdf_literalcode("%f %f l",pth.x_coord,pth.y_coord)
      end
      ith = pth
    end
    if not open then
      local one = path[1]
      if curved(pth,one) then
        pdf_literalcode("%f %f %f %f %f %f c",
          pth.right_x,pth.right_y,one.left_x,one.left_y,one.x_coord,one.y_coord )
      else
        pdf_literalcode("%f %f l",one.x_coord,one.y_coord)
      end
    elseif #path == 1 then -- special case .. draw point
      local one = path[1]
      pdf_literalcode("%f %f l",one.x_coord,one.y_coord)
    end
  end

  local function flushconcatpath(path,open)
    pdf_literalcode("%f %f %f %f %f %f cm", sx, rx, ry, sy, tx ,ty)
    local pth, ith
    for i=1,#path do
      pth = path[i]
      if not ith then
        pdf_literalcode("%f %f m",concat(pth.x_coord,pth.y_coord))
      elseif curved(ith,pth) then
        local a, b = concat(ith.right_x,ith.right_y)
        local c, d = concat(pth.left_x,pth.left_y)
        pdf_literalcode("%f %f %f %f %f %f c",a,b,c,d,concat(pth.x_coord, pth.y_coord))
      else
        pdf_literalcode("%f %f l",concat(pth.x_coord, pth.y_coord))
      end
      ith = pth
    end
    if not open then
      local one = path[1]
      if curved(pth,one) then
        local a, b = concat(pth.right_x,pth.right_y)
        local c, d = concat(one.left_x,one.left_y)
        pdf_literalcode("%f %f %f %f %f %f c",a,b,c,d,concat(one.x_coord, one.y_coord))
      else
        pdf_literalcode("%f %f l",concat(one.x_coord,one.y_coord))
      end
    elseif #path == 1 then -- special case .. draw point
      local one = path[1]
      pdf_literalcode("%f %f l",concat(one.x_coord,one.y_coord))
    end
  end

%    \end{macrocode}
%    Finally, flush figures by inserting PDF literals.
%    \begin{macrocode}
  local function flush (result,flusher)
    if result then
      local figures = result.fig
      if figures then
        for f=1, #figures do
          info("flushing figure %s",f)
          local figure = figures[f]
          local objects = figure:objects()
          local fignum = tonumber(figure:filename():match("([%d]+)$") or figure:charcode() or 0)
          local miterlimit, linecap, linejoin, dashed = -1, -1, -1, false
          local bbox = figure:boundingbox()
          local llx, lly, urx, ury = bbox[1], bbox[2], bbox[3], bbox[4] -- faster than unpack
          if urx < llx then
%    \end{macrocode}
%    luamplib silently ignores this invalid figure for those
%    that do not contain |beginfig ... endfig|. (issue \#70)
%    Original code of \ConTeXt general was:
%\begin{verbatim}
%    -- invalid
%    pdf_startfigure(fignum,0,0,0,0)
%    pdf_stopfigure()
%\end{verbatim}
%    \begin{macrocode}
          else
%    \end{macrocode}
%    For legacy behavior, insert `pre-fig' \TeX\ code here.
%    \begin{macrocode}
            if tex_code_pre_mplib[f] then
              put2output(tex_code_pre_mplib[f])
            end
            pdf_startfigure(fignum,llx,lly,urx,ury)
            start_pdf_code()
            if objects then
              local savedpath = nil
              local savedhtap = nil
              for o=1,#objects do
                local object        = objects[o]
                local objecttype    = object.type
%    \end{macrocode}
%    The following 10 lines are part of |btex...etex| patch.
%    Again, colors are processed at this stage.
%    \begin{macrocode}
                local prescript     = object.prescript
                prescript = prescript and script2table(prescript) -- prescript is now a table
                local cr_over = do_preobj_CR(object,prescript) -- color
                local tr_opaq = do_preobj_TR(object,prescript) -- opacity
                local fading_ = do_preobj_FADE(object,prescript) -- fading
                local pattern_ = do_preobj_PAT(object,prescript) -- tiling pattern
                local shading_ = do_preobj_shading(object,prescript) -- shading pattern
                local trgroup = do_preobj_GRP(object,prescript) -- transparency group
                if prescript and prescript.mplibtexboxid then
                  put_tex_boxes(object,prescript)
                elseif objecttype == "start_bounds" or objecttype == "stop_bounds" then --skip
                elseif objecttype == "start_clip" then
                  local evenodd = not object.istext and object.postscript == "evenodd"
                  start_pdf_code()
                  flushnormalpath(object.path,false)
                  pdf_literalcode(evenodd and "W* n" or "W n")
                elseif objecttype == "stop_clip" then
                  stop_pdf_code()
                  miterlimit, linecap, linejoin, dashed = -1, -1, -1, false
                elseif objecttype == "special" then
%    \end{macrocode}
%    Collect \TeX\ codes that will be executed after flushing.
%    Legacy behavior.
%    \begin{macrocode}
                  if prescript and prescript.postmplibverbtex then
                    figcontents.post[#figcontents.post+1] = prescript.postmplibverbtex
                  end
                elseif objecttype == "text" then
                  local ot = object.transform -- 3,4,5,6,1,2
                  start_pdf_code()
                  pdf_literalcode("%f %f %f %f %f %f cm",ot[3],ot[4],ot[5],ot[6],ot[1],ot[2])
                  pdf_textfigure(object.font,object.dsize,object.text,object.width,object.height,object.depth)
                  stop_pdf_code()
                elseif not trgroup and fading_ ~= "stop" then
                  local evenodd, collect, both = false, false, false
                  local postscript = object.postscript
                  if not object.istext then
                    if postscript == "evenodd" then
                      evenodd = true
                    elseif postscript == "collect" then
                      collect = true
                    elseif postscript == "both" then
                      both = true
                    elseif postscript == "eoboth" then
                      evenodd = true
                      both    = true
                    end
                  end
                  if collect then
                    if not savedpath then
                      savedpath = { object.path or false }
                      savedhtap = { object.htap or false }
                    else
                      savedpath[#savedpath+1] = object.path or false
                      savedhtap[#savedhtap+1] = object.htap or false
                    end
                  else
%    \end{macrocode}
%    Removed from \ConTeXt general: color stuff.
%    \begin{macrocode}
                    local ml = object.miterlimit
                    if ml and ml ~= miterlimit then
                      miterlimit = ml
                      pdf_literalcode("%f M",ml)
                    end
                    local lj = object.linejoin
                    if lj and lj ~= linejoin then
                      linejoin = lj
                      pdf_literalcode("%i j",lj)
                    end
                    local lc = object.linecap
                    if lc and lc ~= linecap then
                      linecap = lc
                      pdf_literalcode("%i J",lc)
                    end
                    local dl = object.dash
                    if dl then
                      local d = format("[%s] %f d",tableconcat(dl.dashes or {}," "),dl.offset)
                      if d ~= dashed then
                        dashed = d
                        pdf_literalcode(dashed)
                      end
                    elseif dashed then
                      pdf_literalcode("[] 0 d")
                      dashed = false
                    end
                    local path = object.path
                    local transformed, penwidth = false, 1
                    local open = path and path[1].left_type and path[#path].right_type
                    local pen = object.pen
                    if pen then
                      if pen.type == 'elliptical' then
                        transformed, penwidth = pen_characteristics(object) -- boolean, value
                        pdf_literalcode("%f w",penwidth)
                        if objecttype == 'fill' then
                          objecttype = 'both'
                        end
                      else -- calculated by mplib itself
                        objecttype = 'fill'
                      end
                    end
%    \end{macrocode}
%    Added : shading
%    \begin{macrocode}
                    local shade_no, shade_stroking = do_preobj_SH(object,prescript) -- shading
                    if shade_no then
                      pdf_literalcode"q /Pattern cs"
                      objecttype = false
                    end
                    if transformed then
                      start_pdf_code()
                    end
                    if path then
                      if savedpath then
                        for i=1,#savedpath do
                          local path = savedpath[i]
                          if transformed then
                            flushconcatpath(path,open)
                          else
                            flushnormalpath(path,open)
                          end
                        end
                        savedpath = nil
                      end
                      if transformed then
                        flushconcatpath(path,open)
                      else
                        flushnormalpath(path,open)
                      end
                      if objecttype == "fill" then
                        pdf_literalcode(evenodd and "h f*" or "h f")
                      elseif objecttype == "outline" then
                        if both then
                          pdf_literalcode(evenodd and "h B*" or "h B")
                        else
                          pdf_literalcode(open and "S" or "h S")
                        end
                      elseif objecttype == "both" then
                        pdf_literalcode(evenodd and "h B*" or "h B")
                      end
                    end
                    if transformed then
                      stop_pdf_code()
                    end
                    local path = object.htap
%    \end{macrocode}
%    How can we generate an |htap| object? Please let us know if you have succeeded.
%    \begin{macrocode}
                    if path then
                      if transformed then
                        start_pdf_code()
                      end
                      if savedhtap then
                        for i=1,#savedhtap do
                          local path = savedhtap[i]
                          if transformed then
                            flushconcatpath(path,open)
                          else
                            flushnormalpath(path,open)
                          end
                        end
                        savedhtap = nil
                        evenodd   = true
                      end
                      if transformed then
                        flushconcatpath(path,open)
                      else
                        flushnormalpath(path,open)
                      end
                      if objecttype == "fill" then
                        pdf_literalcode(evenodd and "h f*" or "h f")
                      elseif objecttype == "outline" then
                        pdf_literalcode(open and "S" or "h S")
                      elseif objecttype == "both" then
                        pdf_literalcode(evenodd and "h B*" or "h B")
                      end
                      if transformed then
                        stop_pdf_code()
                      end
                    end
%    \end{macrocode}
%    Added to \ConTeXt general: post-object colors and shading stuff.
%    Beware |q ... Q| scope.
%    \begin{macrocode}
                    if shade_no then -- shading
                      pdf_literalcode("W%s %s /MPlibSh%s sh Q",
                        evenodd and "*" or "", shade_stroking and "s" or "n", shade_no)
                    end
                  end
                end
                if fading_ == "start" then
                  pdfetcs.fading.specialeffects = {fading_, tr_opaq, cr_over}
                elseif trgroup == "start" then
                  pdfetcs.tr_group.specialeffects = {fading_, tr_opaq, cr_over}
                elseif fading_ == "stop" then
                  local se = pdfetcs.fading.specialeffects
                  if se then stop_special_effects(se[1], se[2], se[3]) end
                elseif trgroup == "stop" then
                  local se = pdfetcs.tr_group.specialeffects
                  if se then stop_special_effects(se[1], se[2], se[3]) end
                else
                  stop_special_effects(fading_, tr_opaq, cr_over)
                end
                if fading_ or trgroup then -- extgs resetted
                  miterlimit, linecap, linejoin, dashed = -1, -1, -1, false
                end
              end
            end
            stop_pdf_code()
            pdf_stopfigure()
%    \end{macrocode}
%    output collected materials to PDF, plus legacy |verbatimtex| code.
%    \begin{macrocode}
            for _,v in ipairs(figcontents) do
              if type(v) == "table" then
                texsprint"\\mplibtoPDF{"; texsprint(v[1], v[2]); texsprint"}"
              else
                texsprint(v)
              end
            end
            if #figcontents.post > 0 then texsprint(figcontents.post) end
            figcontents = { post = { } }
          end
        end
      end
    end
  end

  function luamplib.convert (result, flusher)
    flush(result, flusher)
    return true -- done
  end
end

function luamplib.colorconverter (cr)
  local n = #cr
  if n == 4 then
    local c, m, y, k = cr[1], cr[2], cr[3], cr[4]
    return format("%.3f %.3f %.3f %.3f k %.3f %.3f %.3f %.3f K",c,m,y,k,c,m,y,k), "0 g 0 G"
  elseif n == 3 then
    local r, g, b = cr[1], cr[2], cr[3]
    return format("%.3f %.3f %.3f rg %.3f %.3f %.3f RG",r,g,b,r,g,b), "0 g 0 G"
  else
    local s = cr[1]
    return format("%.3f g %.3f G",s,s), "0 g 0 G"
  end
end
%    \end{macrocode}
%
% \iffalse
%</lua>
% \fi
%
%    \subsection{\texorpdfstring{\TeX}{TeX} package}
%
%
% \iffalse
%<*package>
% \fi
%
%    First we need to load some packages.
%
%    \begin{macrocode}
\ifcsname ProvidesPackage\endcsname
%    \end{macrocode}
% We need \LaTeX\ 2024-06-01 as we use |ltx.pdf.object_id| when pdfmanagement is loaded.
% But as \pkg{fp} package does not accept an option, we do not append the date option.
%    \begin{macrocode}
  \NeedsTeXFormat{LaTeX2e}
  \ProvidesPackage{luamplib}
    [2026/05/26 v2.41.3 mplib package for LuaTeX]
\fi
\ifdefined\newluafunction\else
  \input ltluatex
\fi
%    \end{macrocode}
%
% In DVI mode, a new XObject (mppattern, mplibgroup) must be encapsulated in an \cs{hbox}.
% But this should not affect typesetting. So we use Hook mechanism provided by \LaTeX\ kernel.
% In Plain, \pkg{atbegshi.sty} is loaded.
%    \begin{macrocode}
\ifnum\outputmode=0
  \ifdefined\AddToHookNext
    \def\luamplibatnextshipout{\AddToHookNext{shipout/background}}
    \def\luamplibatfirstshipout{\AddToHook{shipout/firstpage}}
    \def\luamplibateveryshipout{\AddToHook{shipout/background}}
  \else
    \input atbegshi.sty
    \def\luamplibatnextshipout#1{\AtBeginShipoutNext{\AtBeginShipoutAddToBox{#1}}}
    \let\luamplibatfirstshipout\AtBeginShipoutFirst
    \def\luamplibateveryshipout#1{\AtBeginShipout{\AtBeginShipoutAddToBox{#1}}}
  \fi
\fi
%    \end{macrocode}
%
%    Loading of lua code.
%    \begin{macrocode}
\directlua{require("luamplib")}
%    \end{macrocode}
%
%    legacy commands. Seems we don't need it, but no harm.
%    \begin{macrocode}
\ifx\pdfoutput\undefined
  \let\pdfoutput\outputmode
\fi
\ifx\pdfliteral\undefined
  \protected\def\pdfliteral{\pdfextension literal}
\fi
%    \end{macrocode}
%
%    Set the format for \metapost.
%    \begin{macrocode}
\def\mplibsetformat#1{\directlua{luamplib.setformat("#1")}}
%    \end{macrocode}
%
%    luamplib works in both PDF and DVI mode,
%    but only DVIPDFMx is supported currently among a number of DVI tools.
%    So we output a info.
%    \begin{macrocode}
\ifnum\pdfoutput>0
  \let\mplibtoPDF\pdfliteral
\else
  \def\mplibtoPDF#1{\special{pdf:literal direct #1}}
  \ifcsname PackageInfo\endcsname
    \PackageInfo{luamplib}{only dvipdfmx is supported currently}
  \else
    \immediate\write-1{luamplib Info: only dvipdfmx is supported currently}
  \fi
\fi
%    \end{macrocode}
%
%    To make |mplibcode| typeset always in horizontal mode.
%    \begin{macrocode}
\def\mplibforcehmode{\let\prependtomplibbox\leavevmode}
\def\mplibnoforcehmode{\let\prependtomplibbox\relax}
\mplibnoforcehmode
%    \end{macrocode}
%
%    Catcode. We want to allow comment sign in |mplibcode|.
%    \begin{macrocode}
\def\mplibsetupcatcodes{%
  %catcode`\{=12 %catcode`\}=12
  \catcode`\#=12 \catcode`\^=12 \catcode`\~=12 \catcode`\_=12
  \catcode`\&=12 \catcode`\$=12 \catcode`\%=12 \catcode`\^^M=12
}
%    \end{macrocode}
%
%    Make |btex...etex| box zero-metric. Plus address the issue \#189.
%    |bdir 0| seems to be redundant, but no harm.
%    \begin{macrocode}
\ifnum\outputmode>0 %
  \def\mplibputtextbox#1#2#3#4{%
    \pdfextension save\relax
    \vbox to 0pt{\vss
      \hbox bdir0 to 0pt{\kern#2bp\pdfextension setmatrix{#4}\raise\dp#1\copy#1\hss}%
      \kern#3bp}%
    \pdfextension restore\relax}
\else
  \def\mplibputtextbox#1#2#3#4{%
    \special{pdf:btrans matrix #4 #2 #3}%
    \vbox to 0pt{\vss\hbox bdir0 to 0pt{\raise\dp#1\copy#1\hss}}%
    \special{pdf:etrans}}
\fi
%    \end{macrocode}
%
%    use Transparency Group
%    \begin{macrocode}
\protected\def\usemplibgroup#1#{\usemplibgroupmain}
\def\usemplibgroupmain#1{%
  \prependtomplibbox\hbox dir TLT\bgroup
  \csname luamplib.group.#1\endcsname
  \egroup
}
\protected\def\mplibgroup#1{%
  \begingroup
  \def\MPllx{0}\def\MPlly{0}%
  \def\mplibgroupname{#1}%
  \mplibgroupgetnexttok
}
\def\mplibgroupgetnexttok{\futurelet\nexttok\mplibgroupbranch}
\def\mplibgroupskipspace{\afterassignment\mplibgroupgetnexttok\let\nexttok= }
\def\mplibgroupbranch{%
  \ifx [\nexttok
    \expandafter\mplibgroupopts
  \else
    \ifx\mplibsptoken\nexttok
      \expandafter\expandafter\expandafter\mplibgroupskipspace
    \else
      \let\mplibgroupoptions\empty
      \expandafter\expandafter\expandafter\mplibgroupmain
    \fi
  \fi
}
\def\mplibgroupopts[#1]{\def\mplibgroupoptions{#1}\mplibgroupmain}
\def\mplibgroupmain{\setbox\mplibscratchbox\hbox\bgroup\ignorespaces}
\protected\def\endmplibgroup{\egroup
  \directlua{ luamplib.registergroup(
    \the\mplibscratchbox, '\mplibgroupname', {\mplibgroupoptions}
  )}%
  \endgroup
}
%    \end{macrocode}
%
%    Patterns
%    \begin{macrocode}
{\def\:{\global\let\mplibsptoken= } \: }
\protected\def\mppattern#1{%
  \begingroup
  \def\MPllx{0}\def\MPlly{0}%
  \def\mplibpatternname{#1}%
  \mplibpatterngetnexttok
}
\def\mplibpatterngetnexttok{\futurelet\nexttok\mplibpatternbranch}
\def\mplibpatternskipspace{\afterassignment\mplibpatterngetnexttok\let\nexttok= }
\def\mplibpatternbranch{%
  \ifx [\nexttok
    \expandafter\mplibpatternopts
  \else
    \ifx\mplibsptoken\nexttok
      \expandafter\expandafter\expandafter\mplibpatternskipspace
    \else
      \let\mplibpatternoptions\empty
      \expandafter\expandafter\expandafter\mplibpatternmain
    \fi
  \fi
}
\def\mplibpatternopts[#1]{%
  \def\mplibpatternoptions{#1}%
  \mplibpatternmain
}
\def\mplibpatternmain{%
  \setbox\mplibscratchbox\hbox\bgroup\ignorespaces
}
\protected\def\endmppattern{%
  \egroup
  \directlua{ luamplib.registerpattern(
    \the\mplibscratchbox, '\mplibpatternname', {\mplibpatternoptions}
  )}%
  \endgroup
}
%    \end{macrocode}
%
%    simple way to use \mplib:
%    |\mpfig draw fullcircle scaled 10; \endmpfig|
%    \begin{macrocode}
\def\mpfiginstancename{@mpfig}
\protected\def\mpfig{%
  \begingroup
  \futurelet\nexttok\mplibmpfigbranch
}
\def\mplibmpfigbranch{%
  \ifx *\nexttok
    \expandafter\mplibprempfig
  \else
    \ifx [\nexttok
      \expandafter\expandafter\expandafter\mplibgobbleoptsmpfig
    \else
      \expandafter\expandafter\expandafter\mplibmainmpfig
    \fi
  \fi
}
\def\mplibgobbleoptsmpfig[#1]{\mplibmainmpfig}
\def\mplibmainmpfig{%
  \begingroup
  \mplibsetupcatcodes
  \mplibdomainmpfig
}
\long\def\mplibdomainmpfig#1\endmpfig{%
  \endgroup
  \directlua{
    local legacy = luamplib.legacyverbatimtex
    local everympfig = luamplib.everymplib["\mpfiginstancename"] or ""
    local everyendmpfig = luamplib.everyendmplib["\mpfiginstancename"] or ""
    luamplib.legacyverbatimtex = false
    luamplib.everymplib["\mpfiginstancename"] = ""
    luamplib.everyendmplib["\mpfiginstancename"] = ""
    luamplib.process_mplibcode(
    "beginfig(0) "..everympfig.." "..[===[\unexpanded{#1}]===].." "..everyendmpfig.." endfig;",
    "\mpfiginstancename")
    luamplib.legacyverbatimtex = legacy
    luamplib.everymplib["\mpfiginstancename"] = everympfig
    luamplib.everyendmplib["\mpfiginstancename"] = everyendmpfig
  }%
  \endgroup
}
\def\mplibprempfig#1{%
  \begingroup
  \mplibsetupcatcodes
  \mplibdoprempfig
}
\long\def\mplibdoprempfig#1\endmpfig{%
  \endgroup
  \directlua{
    local legacy = luamplib.legacyverbatimtex
    local everympfig = luamplib.everymplib["\mpfiginstancename"]
    local everyendmpfig = luamplib.everyendmplib["\mpfiginstancename"]
    luamplib.legacyverbatimtex = false
    luamplib.everymplib["\mpfiginstancename"] = ""
    luamplib.everyendmplib["\mpfiginstancename"] = ""
    luamplib.process_mplibcode([===[\unexpanded{#1}]===],"\mpfiginstancename")
    luamplib.legacyverbatimtex = legacy
    luamplib.everymplib["\mpfiginstancename"] = everympfig
    luamplib.everyendmplib["\mpfiginstancename"] = everyendmpfig
  }%
  \endgroup
}
\protected\def\endmpfig{endmpfig}
%    \end{macrocode}
%
%    The Plain-specific stuff.
%    \begin{macrocode}
\unless\ifcsname ver@luamplib.sty\endcsname
  \def\mplibcodegetinstancename[#1]{\xdef\currentmpinstancename{#1}\mplibcodeindeed}
  \protected\def\mplibcode{%
    \begingroup
    \futurelet\nexttok\mplibcodebranch
  }
  \def\mplibcodebranch{%
    \ifx [\nexttok
      \expandafter\mplibcodegetinstancename
    \else
      \global\let\currentmpinstancename\empty
      \expandafter\mplibcodeindeed
    \fi
  }
  \def\mplibcodeindeed{%
    \begingroup
    \mplibsetupcatcodes
    \mplibdocode
  }
  \long\def\mplibdocode#1\endmplibcode{%
    \endgroup
    \directlua{luamplib.process_mplibcode([===[\unexpanded{#1}]===],"\currentmpinstancename")}%
    \endgroup
  }
  \protected\def\endmplibcode{endmplibcode}
\else
%    \end{macrocode}
%
%    The \LaTeX-specific part: a new environment.
%    \begin{macrocode}
  \newenvironment{mplibcode}[1][]{%
    \xdef\currentmpinstancename{#1}%
    \mplibtmptoks{}\ltxdomplibcode
  }{}
  \def\ltxdomplibcode{%
    \begingroup
    \mplibsetupcatcodes
    \ltxdomplibcodeindeed
  }
  \def\mplib@mplibcode{mplibcode}
  \long\def\ltxdomplibcodeindeed#1\end#2{%
    \endgroup
    \mplibtmptoks\expandafter{\the\mplibtmptoks#1}%
    \def\mplibtemp@a{#2}%
    \ifx\mplib@mplibcode\mplibtemp@a
      \directlua{luamplib.process_mplibcode([===[\the\mplibtmptoks]===],"\currentmpinstancename")}%
      \end{mplibcode}%
    \else
      \mplibtmptoks\expandafter{\the\mplibtmptoks\end{#2}}%
      \expandafter\ltxdomplibcode
    \fi
  }
\fi
%    \end{macrocode}
%
%    User settings.
%    \begin{macrocode}
\def\mplibshowlog#1{\directlua{
    local s = string.lower("#1")
    if s == "enable" or s == "true" or s == "yes" then
      luamplib.showlog = true
    else
      luamplib.showlog = false
    end
}}
\def\mpliblegacybehavior#1{\directlua{
    local s = string.lower("#1")
    if s == "enable" or s == "true" or s == "yes" then
      luamplib.legacyverbatimtex = true
    else
      luamplib.legacyverbatimtex = false
    end
}}
\def\mplibverbatim#1{\directlua{
    local s = string.lower("#1")
    if s == "enable" or s == "true" or s == "yes" then
      luamplib.verbatiminput = true
    else
      luamplib.verbatiminput = false
    end
}}
\newtoks\mplibtmptoks
%    \end{macrocode}
%
%    \cs{everymplib} \& \cs{everyendmplib}: macros resetting
%    |luamplib.every(end)mplib| tables
%
%    \begin{macrocode}
\ifcsname ver@luamplib.sty\endcsname
  \protected\def\everymplib{%
    \begingroup
    \mplibsetupcatcodes
    \mplibdoeverymplib
  }
  \protected\def\everyendmplib{%
    \begingroup
    \mplibsetupcatcodes
    \mplibdoeveryendmplib
  }
  \newcommand\mplibdoeverymplib[2][]{%
    \endgroup
    \directlua{
      luamplib.everymplib["#1"] = [===[\unexpanded{#2}]===]
    }%
  }
  \newcommand\mplibdoeveryendmplib[2][]{%
    \endgroup
    \directlua{
      luamplib.everyendmplib["#1"] = [===[\unexpanded{#2}]===]
    }%
  }
\else
  \def\mplibgetinstancename[#1]{\def\currentmpinstancename{#1}}
  \protected\def\everymplib#1#{%
    \ifx\empty#1\empty \mplibgetinstancename[]\else \mplibgetinstancename#1\fi
    \begingroup
    \mplibsetupcatcodes
    \mplibdoeverymplib
  }
  \long\def\mplibdoeverymplib#1{%
    \endgroup
    \directlua{
      luamplib.everymplib["\currentmpinstancename"] = [===[\unexpanded{#1}]===]
    }%
  }
  \protected\def\everyendmplib#1#{%
    \ifx\empty#1\empty \mplibgetinstancename[]\else \mplibgetinstancename#1\fi
    \begingroup
    \mplibsetupcatcodes
    \mplibdoeveryendmplib
  }
  \long\def\mplibdoeveryendmplib#1{%
    \endgroup
    \directlua{
      luamplib.everyendmplib["\currentmpinstancename"] = [===[\unexpanded{#1}]===]
    }%
  }
\fi
%    \end{macrocode}
%
%    \TeX\ macros for dimen/color
%    \begin{macrocode}
\def\mpdim#1{ runscript("luamplibdimen{#1}") }
\def\mpcolor#1#{\domplibcolor{#1}}
\def\domplibcolor#1#2{ runscript("luamplibcolor{#1{#2}}") }
%    \end{macrocode}
%
%    \mplib's number system. Now |binary| has gone away.
%    \begin{macrocode}
\def\mplibnumbersystem#1{\directlua{
  local t = "#1"
  if t == "binary" then t = "decimal" end
  luamplib.numbersystem = t
}}
%    \end{macrocode}
%
%    Settings for |.mp| cache files.
%    \begin{macrocode}
\def\mplibmakenocache#1{\mplibdomakenocache #1,\stop,}
\def\mplibdomakenocache#1,{%
  \ifx\empty#1\empty
    \expandafter\mplibdomakenocache
  \else
    \ifx\stop#1\else
      \directlua{luamplib.noneedtoreplace["#1.mp"]=true}%
      \expandafter\expandafter\expandafter\mplibdomakenocache
    \fi
  \fi
}
\def\mplibcancelnocache#1{\mplibdocancelnocache #1,\stop,}
\def\mplibdocancelnocache#1,{%
  \ifx\empty#1\empty
    \expandafter\mplibdocancelnocache
  \else
    \ifx\stop#1\else
      \directlua{luamplib.noneedtoreplace["#1.mp"]=false}%
      \expandafter\expandafter\expandafter\mplibdocancelnocache
    \fi
  \fi
}
\def\mplibcachedir#1{\directlua{luamplib.getcachedir("\unexpanded{#1}")}}
%    \end{macrocode}
%
%    More user settings.
%    \begin{macrocode}
\def\mplibtextextlabel#1{\directlua{
    local s = string.lower("#1")
    if s == "enable" or s == "true" or s == "yes" then
      luamplib.textextlabel = true
    else
      luamplib.textextlabel = false
    end
}}
\def\mplibcodeinherit#1{\directlua{
    local s = string.lower("#1")
    if s == "enable" or s == "true" or s == "yes" then
      luamplib.codeinherit = true
    else
      luamplib.codeinherit = false
    end
}}
\def\mplibglobaltextext#1{\directlua{
    local s = string.lower("#1")
    if s == "enable" or s == "true" or s == "yes" then
      luamplib.globaltextext = true
    else
      luamplib.globaltextext = false
    end
}}
%    \end{macrocode}
%
%    The followings are from \ConTeXt general, mostly.
%
%    We use a dedicated scratchbox.
%    \begin{macrocode}
\ifx\mplibscratchbox\undefined \newbox\mplibscratchbox \fi
%    \end{macrocode}
%
%    We encapsulate the literals.
%    \begin{macrocode}
\def\mplibstarttoPDF#1#2#3#4{%
  \prependtomplibbox
  \hbox dir TLT\bgroup
  \xdef\MPllx{#1}\xdef\MPlly{#2}%
  \xdef\MPurx{#3}\xdef\MPury{#4}%
  \xdef\MPwidth{\the\dimexpr#3bp-#1bp\relax}%
  \xdef\MPheight{\the\dimexpr#4bp-#2bp\relax}%
  \parskip0pt%
  \leftskip0pt%
  \parindent0pt%
  \everypar{}%
  \setbox\mplibscratchbox\vbox\bgroup
  \noindent
}
\def\mplibstoptoPDF{%
  \par
  \egroup %
  \setbox\mplibscratchbox\hbox %
    {\hskip-\MPllx bp%
     \raise-\MPlly bp%
     \box\mplibscratchbox}%
  \setbox\mplibscratchbox\vbox to \MPheight
    {\vfill
     \hsize\MPwidth
     \wd\mplibscratchbox0pt%
     \ht\mplibscratchbox0pt%
     \dp\mplibscratchbox0pt%
     \box\mplibscratchbox}%
  \wd\mplibscratchbox\MPwidth
  \ht\mplibscratchbox\MPheight
  \box\mplibscratchbox
  \egroup
}
%    \end{macrocode}
%
%    Text items have a special handler.
%    \begin{macrocode}
\def\mplibtextext#1#2#3#4#5{%
  \begingroup
  \setbox\mplibscratchbox\hbox
    {\font\temp=#1 at #2bp%
     \temp
     #3}%
  \setbox\mplibscratchbox\hbox
    {\hskip#4 bp%
     \raise#5 bp%
     \box\mplibscratchbox}%
  \wd\mplibscratchbox0pt%
  \ht\mplibscratchbox0pt%
  \dp\mplibscratchbox0pt%
  \box\mplibscratchbox
  \endgroup
}
%    \end{macrocode}
%
%    Input |luamplib.cfg| when it exists.
%    \begin{macrocode}
\openin0=luamplib.cfg
\ifeof0 \else
  \closein0
  \input luamplib.cfg
\fi
%    \end{macrocode}
%
%    Code for \pkg{tagpdf}
%    \begin{macrocode}
\def\luamplibtagtextboxset#1#2{#2}
\let\luamplibnotagtextboxset\luamplibtagtextboxset
\let\luamplibtagasgroupset\relax
\let\luamplibtagasgroupput\luamplibtagtextboxset
\ifcsname SuspendTagging\endcsname\else\endinput\fi
\ifcsname ver@tagpdf.sty\endcsname \else
  \ExplSyntaxOn
  \keys_define:nn{luamplib/tagging}
    {
      ,alt          .code:n = { }
      ,actualtext   .code:n = { }
      ,artifact     .code:n = { }
      ,text         .code:n = { }
      ,off          .code:n = { }
      ,tag          .code:n = { }
      ,adjust-BBox  .code:n = { }
      ,tagging-setup .code:n = { }
      ,instance     .code:n = { \tl_gset:Nn \currentmpinstancename {#1} }
      ,instancename .meta:n = { instance = {#1} }
      ,unknown      .code:n = { \tl_gset:NV \currentmpinstancename \l_keys_key_str }
    }
  \RenewDocumentCommand\mplibcode{O{}}
    {
      \tl_gclear:N \currentmpinstancename
      \keys_set:ne{luamplib/tagging}{#1}
      \mplibtmptoks{}\ltxdomplibcode
    }
  \cs_set_eq:NN \mplibalttext \use_none:n
  \cs_set_eq:NN \mplibactualtext \use_none:n
%    \end{macrocode}
%  2025/12/05:
%  |\begin{center}\mpfig ...\endmpfig\end{center}| raises an Error!
%  as we issue |\everypar{}| before flushing literals out.
%  It is related to \cs{partokencontext=2} recently introduced by \LaTeX.
%  Why we used |vbox| initially? where |hbox| seems to be sufficient.  Anyway,
%  among various solutions including |\partokencontext\z@|, |\let\par\@@par|, and \cs{endgraf},
%  we here attempt to address the issue by adding the following line,
%  which \LaTeX's \cs{everypar} should have done.
%    \begin{macrocode}
  \tl_put_left:Nn \mplibstoptoPDF \@newlistfalse
  \ExplSyntaxOff
  \endinput\fi
\ExplSyntaxOn
\tl_new:N \l__luamplib_tag_envname_tl
\tl_new:N \l__luamplib_tag_alt_tl
\tl_new:N \l__luamplib_tag_alt_dflt_tl
\tl_new:N \l__luamplib_tag_actual_tl
\tl_new:N \l__luamplib_tag_struct_tl
\tl_set:Nn\l__luamplib_tag_struct_tl {Figure}
\bool_new:N \l__luamplib_tag_usetext_bool
\bool_new:N \l__luamplib_tag_bboxcorr_bool
\seq_new:N  \l__luamplib_tag_bboxcorr_seq
\tl_new:N \l__luamplib_tag_bbox_draw_tl
\tl_new:N \l__luamplib_BBox_llx_tl
\tl_new:N \l__luamplib_BBox_lly_tl
\tl_new:N \l__luamplib_BBox_urx_tl
\tl_new:N \l__luamplib_BBox_ury_tl
\msg_new:nnn {luamplib}{figure-text-reuse}
{
  tex-text~box~#1~probably~is~incorrectly~tagged.~
  Reusing~a~box~in~text~mode~is~strongly~discouraged.~
  Check~the~resulting~PDF.
}
\msg_new:nnn {luamplib}{mplibgroup-text-mode}
{
  mplibgroup~'#1'~probably~is~incorrectly~tagged.~
  Using~mplibgroup~with~text~mode~is~not~recommended.~
  Check~the~resulting~PDF.
}
\msg_new:nnn{luamplib}{alt-text-missing}
{
  Alternate~text~for~#1~is~missing.~
  Using~the~default~value~'#2'~instead.
}
%    \end{macrocode}
% Sockets for tex-text boxes.
%    \begin{macrocode}
\socket_new:nn{tagsupport/luamplib/textext/set}{2}
\socket_new:nn{tagsupport/luamplib/textext/put}{2}
\socket_new_plug:nnn{tagsupport/luamplib/textext/set}{default}
{
%    \end{macrocode}
% TODO: we check |text| mode here.
% If we tag text boxes for all modes, we will get a lot of structure-has-no-parent warning;
% no good-looking, though it seems to be no harm.
%    \begin{macrocode}
  \bool_if:NTF \l__luamplib_tag_usetext_bool
  {
    \tag_mc_end_push:
    \tag_struct_begin:n{tag=NonStruct, stash, parent-tag=text}
    \cs_gset_nopar:cpe {luamplib.taggedbox.#1} {\tag_get:n{struct_num}}
%    \end{macrocode}
% TODO: We force an MC. Otherwise |a| and |b| in |btex a $x$ b etex| are not tagged.
%    \begin{macrocode}
    \tag_mc_begin:n{tag=text}
    #2
    \tag_mc_end:
    \tag_struct_end:
    \tag_mc_begin_pop:n{}
  }
  {
    \tag_suspend:n{\luamplibtagtextboxset}
    #2
    \tag_resume:n{\luamplibtagtextboxset}
  }
}
\socket_new_plug:nnn{tagsupport/luamplib/textext/put}{default}
{
  \bool_lazy_and:nnTF
  { \l__luamplib_tag_usetext_bool }
  { \cs_if_free_p:c {luamplib.notaggedbox.#1} }
  {
    \tag_resume:n{\mplibputtextbox}
    \tag_mc_end:
    \cs_if_exist:cTF {luamplib.taggedbox.#1}
    {
      \exp_args:Nc \tag_struct_use_num:n {luamplib.taggedbox.#1}
      #2
      \cs_undefine:c {luamplib.taggedbox.#1}
    }
    {
      \msg_warning:nnn{luamplib}{figure-text-reuse}{#1}
      \tag_mc_begin:n{}
      \int_set:Nn \l_tmpa_int {#1}
      \tag_mc_reset_box:N \l_tmpa_int
      #2
      \tag_mc_end:
    }
    \tag_mc_begin:n{artifact}
  }
  {
    \int_set:Nn \l_tmpa_int {#1}
    \tag_mc_reset_box:N \l_tmpa_int
    #2
  }
}
\socket_assign_plug:nn{tagsupport/luamplib/textext/set}{default}
\socket_assign_plug:nn{tagsupport/luamplib/textext/put}{default}
\cs_set_nopar:Npn \luamplibtagtextboxset
{
  \tag_socket_use:nnn{luamplib/textext/set}
}
%    \end{macrocode}
% For tex-text boxes starting with |[taggingoff]|, which we will not tag at all.
% They will be just in the artifact MC-chunks.
%    \begin{macrocode}
\cs_set_nopar:Npn \luamplibnotagtextboxset #1 #2
{
  \bool_set_eq:NN \l_tmpa_bool \l__luamplib_tag_usetext_bool
  \bool_set_false:N \l__luamplib_tag_usetext_bool
  \tag_socket_use:nnn{luamplib/textext/set}{#1}{#2}
  \cs_gset_nopar:cpn {luamplib.notaggedbox.#1}{#1}
  \bool_set_eq:NN \l__luamplib_tag_usetext_bool \l_tmpa_bool
}
\sys_if_output_pdf:TF
{
  \cs_set_nopar:Npn \mplibputtextbox #1 #2 #3 #4
  {
    \pdfextension save\relax
    \vbox to 0pt{\vss
      \hbox bdir0 to 0pt{\kern #2bp \pdfextension setmatrix {#4}
        \socket_use:nnn{tagsupport/luamplib/textext/put}{#1}{\raise\dp#1\copy#1}\hss}
      \kern #3bp}
    \pdfextension restore\relax
  }
}
{
  \cs_set_nopar:Npn \mplibputtextbox #1 #2 #3 #4
  {
    \special{pdf:btrans~matrix~#4~#2~#3}
    \vbox to 0pt{\vss\hbox bdir0 to 0pt{
      \socket_use:nnn{tagsupport/luamplib/textext/put}{#1}{\raise\dp#1\copy#1}\hss}}
    \special{pdf:etrans}
  }
}
%    \end{macrocode}
% TODO: Not sure whether asgroup/mplibgroup with |text| mode will be tagged correctly.
%       Probably not. At least, this will raise a warning.
%    \begin{macrocode}
\cs_set_nopar:Npn \luamplibtagasgroupset
{
  \bool_set_false:N \l__luamplib_tag_usetext_bool
}
\cs_set_nopar:Npn \luamplibtagasgroupput
{
  \bool_if:NT \l__luamplib_tag_usetext_bool { \tag_resume:n{\luamplibtagasgroupput} }
  \tag_socket_use:nnn{luamplib/mplibgroup/put}
}
%    \end{macrocode}
% A socket for mplibgroup. Again, we issue a warning upon |text| mode.
%    \begin{macrocode}
\socket_new:nn{tagsupport/luamplib/mplibgroup/put}{2}
\socket_new_plug:nnn{tagsupport/luamplib/mplibgroup/put}{default}
{
  \cs_if_free:cT {luamplib.mplibgroup.text.#1}
  {
    \msg_warning:nnn {luamplib} {mplibgroup-text-mode} {#1}
    \cs_gset_nopar:cpn {luamplib.mplibgroup.text.#1} {#1}
  }
  \tag_mc_end:
  \tag_mc_begin:n{tag=text}
  #2
  \tag_mc_end:
  \tag_mc_begin:n{artifact}
}
\socket_assign_plug:nn{tagsupport/luamplib/mplibgroup/put}{default}
%    \end{macrocode}
% A macro for BBox attribute
%    \begin{macrocode}
\cs_set_nopar:Npn \__luamplib_tag_bbox_attribute:n #1
{
  \tl_set:Ne \l_tmpa_tl {luamplib.BBox.\tag_get:n{struct_num}}
  \tex_savepos:D
  \property_record:ee{\l_tmpa_tl}{xpos,ypos}
  \tl_set:Ne \l__luamplib_BBox_llx_tl
    { \dim_to_decimal_in_bp:n { \property_ref:een {\l_tmpa_tl}{xpos}{0}sp } }
  \tl_set:Ne \l__luamplib_BBox_lly_tl
    { \dim_to_decimal_in_bp:n { \property_ref:een {\l_tmpa_tl}{ypos}{0}sp - \dp#1 } }
  \tl_set:Ne \l__luamplib_BBox_urx_tl
    { \dim_to_decimal_in_bp:n { \l__luamplib_BBox_llx_tl bp + \wd#1 } }
  \tl_set:Ne \l__luamplib_BBox_ury_tl
    { \dim_to_decimal_in_bp:n { \l__luamplib_BBox_lly_tl bp + \ht#1 + \dp#1 } }
  \bool_if:NT \l__luamplib_tag_bboxcorr_bool
  {
    \int_zero:N \l_tmpa_int
    \tl_map_inline:nn
    {
      \l__luamplib_BBox_llx_tl
      \l__luamplib_BBox_lly_tl
      \l__luamplib_BBox_urx_tl
      \l__luamplib_BBox_ury_tl
    }
    {
      \int_incr:N \l_tmpa_int
      \tl_set:Ne ##1
      {
        \fp_eval:n
        {
          ##1
          +
          \dim_to_decimal_in_bp:n { \seq_item:NV \l__luamplib_tag_bboxcorr_seq \l_tmpa_int }
        }
      }
    }
  }
  \tag_struct_gput:ene {\tag_get:n{struct_num}} {attribute}
  {
    /O /Layout /BBox [
      \l__luamplib_BBox_llx_tl\c_space_tl
      \l__luamplib_BBox_lly_tl\c_space_tl
      \l__luamplib_BBox_urx_tl\c_space_tl
      \l__luamplib_BBox_ury_tl
    ]
  }
  \bool_if:NT \l__tag_graphic_debug_bool
  {
    \iow_log:e
    {
      luamplib/tagging~debug:~BBox~of~structure~\tag_get:n{struct_num}~is~
      \l__luamplib_BBox_llx_tl\c_space_tl
      \l__luamplib_BBox_lly_tl\c_space_tl
      \l__luamplib_BBox_urx_tl\c_space_tl
      \l__luamplib_BBox_ury_tl
    }
    \sys_if_output_pdf:TF
    {
      \tl_set:Ne \l__luamplib_tag_bbox_draw_tl
      {
        \pdfextension save\relax
        \opacity_select:n{0.5} \color_select:n{red}
        \pdfextension literal~text
        {
          \l__luamplib_BBox_llx_tl\c_space_tl
          \l__luamplib_BBox_lly_tl\c_space_tl
          \fp_eval:n { \l__luamplib_BBox_urx_tl - \l__luamplib_BBox_llx_tl }~
          \fp_eval:n { \l__luamplib_BBox_ury_tl - \l__luamplib_BBox_lly_tl }~
          re~f
        }
        \pdfextension restore\relax
      }
    }
    {
      \tl_set:Ne \l__luamplib_tag_bbox_draw_tl
      {
        \special{pdf:bcontent}
        \opacity_select:n{0.5} \color_select:n{red}
        \special{pdf:code~
          1~0~0~1~
          -\dim_to_decimal_in_bp:n { \property_ref:een{\l_tmpa_tl}{xpos}{0}sp + \wd#1 }~
          -\dim_to_decimal_in_bp:n { \property_ref:een{\l_tmpa_tl}{ypos}{0}sp }~
          cm
        }
        \special{pdf:code~
          \l__luamplib_BBox_llx_tl\c_space_tl
          \l__luamplib_BBox_lly_tl\c_space_tl
          \fp_eval:n { \l__luamplib_BBox_urx_tl - \l__luamplib_BBox_llx_tl }~
          \fp_eval:n { \l__luamplib_BBox_ury_tl - \l__luamplib_BBox_lly_tl }~
          re~f
        }
        \special{pdf:econtent}
      }
    }
  }
}
%    \end{macrocode}
% Sockets for main process
%    \begin{macrocode}
\socket_new:nn{tagsupport/luamplib/figure/begin}{1}
\socket_new:nn{tagsupport/luamplib/figure/end}{2}
\socket_new_plug:nnn{tagsupport/luamplib/figure/end}{transparent}{#2}
\socket_new_plug:nnn{tagsupport/luamplib/figure/begin}{alt}
{
    \tag_mc_end_push:
    \tl_if_empty:NT\l__luamplib_tag_alt_tl
    {
      \tl_if_empty:eTF{#1}
        { \tl_set:Nn \l__luamplib_tag_alt_tl {metapost~figure} }
        { \tl_set:Ne \l__luamplib_tag_alt_tl {metapost~figure~\text_purify:n{#1}} }
      \msg_warning:nnVV{luamplib}{alt-text-missing}
                       \l__luamplib_tag_envname_tl \l__luamplib_tag_alt_tl
    }
    \tag_struct_begin:n
    {
      tag=\l__luamplib_tag_struct_tl,
      alt=\l__luamplib_tag_alt_tl,
    }
    \tag_mc_begin:n{}
}
\socket_new_plug:nnn{tagsupport/luamplib/figure/end}{alt}
{
    \__luamplib_tag_bbox_attribute:n {#1}
    #2
    \tl_use:N \l__luamplib_tag_bbox_draw_tl
    \tag_mc_end:
    \tag_struct_end:
    \tag_mc_begin_pop:n{}
}
\socket_new_plug:nnn{tagsupport/luamplib/figure/begin}{actualtext}
{
    \tag_mc_end_push:
    \tag_struct_begin:n
    {
      tag=Span,
      actualtext=\l__luamplib_tag_actual_tl,
    }
    \tag_mc_begin:n{}
}
\socket_new_plug:nnn{tagsupport/luamplib/figure/end}{actualtext}
{
    #2
    \tag_mc_end:
    \tag_struct_end:
    \tag_mc_begin_pop:n{}
}
\socket_new_plug:nnn{tagsupport/luamplib/figure/begin}{artifact}
{
    \tag_mc_end_push:
    \tag_mc_begin:n{artifact}
}
\socket_new_plug:nnn{tagsupport/luamplib/figure/end}{artifact}
{
    #2
    \tag_mc_end:
    \tag_mc_begin_pop:n{}
}
%    \end{macrocode}
% A socket for tagging init, so that we can declare
% |\SetKeys[luamplib/tagging]{...}| anywhere in the document.
%    \begin{macrocode}
\socket_new:nn{tagsupport/luamplib/figure/init}{0}
\socket_new_plug:nnn{tagsupport/luamplib/figure/init}{alt}
{
  \socket_assign_plug:nn{tagsupport/luamplib/figure/begin}{alt}
  \socket_assign_plug:nn{tagsupport/luamplib/figure/end}{alt}
}
\socket_new_plug:nnn{tagsupport/luamplib/figure/init}{actualtext}
{
  \socket_assign_plug:nn{tagsupport/luamplib/figure/begin}{actualtext}
  \socket_assign_plug:nn{tagsupport/luamplib/figure/end}{actualtext}
%    \end{macrocode}
% In vmode, hmode will be forced by \cs{noindent} upon |actualtext| and |text| modes.
%    \begin{macrocode}
  \prependtomplibbox \mplibnoforcehmode
  \mode_if_vertical:T { \noindent \aftergroup\par }
}
\socket_new_plug:nnn{tagsupport/luamplib/figure/init}{artifact}
{
  \socket_assign_plug:nn{tagsupport/luamplib/figure/begin}{artifact}
  \socket_assign_plug:nn{tagsupport/luamplib/figure/end}{artifact}
}
\socket_new_plug:nnn{tagsupport/luamplib/figure/init}{text}
{
  \bool_set_true:N \l__luamplib_tag_usetext_bool
  \socket_assign_plug:nn{tagsupport/luamplib/figure/begin}{artifact}
  \socket_assign_plug:nn{tagsupport/luamplib/figure/end}{artifact}
  \prependtomplibbox \mplibnoforcehmode
  \mode_if_vertical:T { \noindent \aftergroup\par }
}
\socket_new_plug:nnn{tagsupport/luamplib/figure/init}{off}
{
  \socket_assign_plug:nn{tagsupport/luamplib/figure/begin}{noop}
  \socket_assign_plug:nn{tagsupport/luamplib/figure/end}{transparent}
}
\socket_assign_plug:nn{tagsupport/luamplib/figure/init}{alt}
%    \end{macrocode}
% Key-value options
%    \begin{macrocode}
\keys_define:nn{luamplib/tagging}
{
  ,alt .code:n =
  {
    \tl_set:Ne\l__luamplib_tag_alt_tl{\text_purify:n{#1}}
    \socket_assign_plug:nn{tagsupport/luamplib/figure/init}{alt}
  }
  ,actualtext .code:n =
  {
    \tl_set:Ne\l__luamplib_tag_actual_tl{\text_purify:n{#1}}
    \socket_assign_plug:nn{tagsupport/luamplib/figure/init}{actualtext}
  }
  ,artifact .code:n = { \socket_assign_plug:nn{tagsupport/luamplib/figure/init}{artifact} }
  ,text     .code:n = { \socket_assign_plug:nn{tagsupport/luamplib/figure/init}{text} }
  ,off      .code:n = { \socket_assign_plug:nn{tagsupport/luamplib/figure/init}{off} }
  ,tag      .code:n =
  {
    \str_case:nnF {#1}
    {
      {false}    { \keys_set:nn {luamplib/tagging} {off} }
      {artifact} { \keys_set:nn {luamplib/tagging} {artifact} }
    }
    {
      \tl_set:Nn\l__luamplib_tag_struct_tl{#1}
      \socket_assign_plug:nn{tagsupport/luamplib/figure/init}{alt}
    }
  }
  ,adjust-BBox .code:n =
  {
    \bool_set_true:N \l__luamplib_tag_bboxcorr_bool
    \seq_set_split:Nnn \l__luamplib_tag_bboxcorr_seq{~}{#1~0pt~0pt~0pt~0pt}
  }
  ,tagging-setup .code:n = { \keys_set_known:nn {luamplib/tagging} {#1} }
}
\keys_define:nn {luamplib/instance}
{
  ,instance     .code:n = { \tl_gset:Nn \currentmpinstancename {#1} }
  ,instancename .meta:n = { instance = {#1} }
  ,unknown      .code:n = { \tl_gset:NV \currentmpinstancename \l_keys_key_str }
}
%    \end{macrocode}
% Redefine our macros
%    \begin{macrocode}
\cs_set_nopar:Npn \mplibstarttoPDF #1 #2 #3 #4
{
  \prependtomplibbox
  \hbox dir~TLT\bgroup
    \tag_socket_use:nn{luamplib/figure/begin}\l__luamplib_tag_alt_dflt_tl
    \xdef\MPllx{#1}\xdef\MPlly{#2}%
    \xdef\MPurx{#3}\xdef\MPury{#4}%
    \xdef\MPwidth{\the\dimexpr#3bp-#1bp\relax}%
    \xdef\MPheight{\the\dimexpr#4bp-#2bp\relax}%
    \parskip0pt
    \leftskip0pt
    \parindent0pt
    \everypar{}%
    \setbox\mplibscratchbox\vbox\bgroup
      \tag_suspend:n{\mplibstarttoPDF}
      \noindent
}
\cs_set_nopar:Npn \mplibstoptoPDF
{
      \par
    \egroup
    \setbox\mplibscratchbox\hbox
      {\hskip-\MPllx bp
       \raise-\MPlly bp
       \box\mplibscratchbox}%
    \setbox\mplibscratchbox\vbox to \MPheight
      {\vfill
       \hsize\MPwidth
       \wd\mplibscratchbox0pt
       \ht\mplibscratchbox0pt
       \dp\mplibscratchbox0pt
       \box\mplibscratchbox}%
    \wd\mplibscratchbox\MPwidth
    \ht\mplibscratchbox\MPheight
    \tag_socket_use:nnn{luamplib/figure/end}{\mplibscratchbox}{\box\mplibscratchbox}
  \egroup
}
\RenewDocumentCommand\mplibcode{O{}}
{
  \tl_set:Nn \l__luamplib_tag_envname_tl {mplibcode}
  \tl_gclear:N \currentmpinstancename
  \keys_set_known:neN {luamplib/tagging} {#1} \l_tmpa_tl
  \keys_set:nV {luamplib/instance} \l_tmpa_tl
  \tl_set_eq:NN \l__luamplib_tag_alt_dflt_tl \currentmpinstancename
  \tag_socket_use:n{luamplib/figure/init}
  \mplibtmptoks{}\ltxdomplibcode
}
\RenewDocumentCommand\mpfig{s O{}}
{
  \begingroup
  \tl_set:Nn \l__luamplib_tag_envname_tl {mpfig}
  \keys_set_known:ne {luamplib/tagging} {#2}
  \tl_set_eq:NN \l__luamplib_tag_alt_dflt_tl \mpfiginstancename
  \tag_socket_use:n{luamplib/figure/init}
  \IfBooleanTF{#1} { \mplibprempfig * }
                   { \mplibmainmpfig }
}
\RenewDocumentCommand\usemplibgroup{O{} m}
{
  \begingroup
  \tl_set:Nn \l__luamplib_tag_envname_tl {usemplibgroup}
  \keys_set_known:ne {luamplib/tagging} {#1}
  \tag_socket_use:n{luamplib/figure/init}
  \prependtomplibbox\hbox dir~TLT\bgroup
    \tag_socket_use:nn{luamplib/figure/begin}{#2}
    \setbox\mplibscratchbox\hbox\bgroup
      \bool_if:NF \l__luamplib_tag_usetext_bool { \tag_suspend:n{\usemplibgroup} }
      \tag_socket_use:nnn{luamplib/mplibgroup/put}{#2}{\csname luamplib.group.#2\endcsname}
    \egroup
    \tag_socket_use:nnn{luamplib/figure/end}{\mplibscratchbox}{\unhbox\mplibscratchbox}
  \egroup
  \endgroup
}
%    \end{macrocode}
% Allow setting alt/actual text within \metapost code.
% Of course we can use them in \TeX\ code as well.
%    \begin{macrocode}
\cs_new_nopar:Npn \mplibalttext #1
{
  \tl_set:Ne \l__luamplib_tag_alt_tl {\text_purify:n{#1}}
}
\cs_new_nopar:Npn \mplibactualtext #1
{
  \tl_set:Ne \l__luamplib_tag_actual_tl {\text_purify:n{#1}}
}
\ExplSyntaxOff
%    \end{macrocode}
%
%    That's all folks!
%
% \iffalse
%</package>
% \fi
%
% \clearpage
% \section{The GNU GPL License v2}
%
% The GPL requires the complete license text to be distributed along
% with the code. I recommend the canonical source, instead:
% \url{http://www.gnu.org/licenses/old-licenses/gpl-2.0.html}.
% But if you insist on an included copy, here it is.
% You might want to zoom in.
%
% \newsavebox{\gpl}
% \begin{lrbox}{\gpl}
% \begin{minipage}{3\textwidth}
% \columnsep=3\columnsep
% \begin{multicols}{3}
% \begin{center}
% {\Large GNU GENERAL PUBLIC LICENSE\par}
% \bigskip
% {Version 2, June 1991}
% \end{center}
%
% \begin{center}
% {\parindent 0in
%
% Copyright \textcopyright\ 1989, 1991 Free Software Foundation, Inc.
%
% \bigskip
%
% 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
%
% \bigskip
%
% Everyone is permitted to copy and distribute verbatim copies
% of this license document, but changing it is not allowed.
% }
% \end{center}
%
% \begin{center}
% {\bf\large Preamble}
% \end{center}
%
%
% The licenses for most software are designed to take away your freedom to
% share and change it.  By contrast, the GNU General Public License is
% intended to guarantee your freedom to share and change free software---to
% make sure the software is free for all its users.  This General Public
% License applies to most of the Free Software Foundation's software and to
% any other program whose authors commit to using it.  (Some other Free
% Software Foundation software is covered by the GNU Library General Public
% License instead.)  You can apply it to your programs, too.
%
% When we speak of free software, we are referring to freedom, not price.
% Our General Public Licenses are designed to make sure that you have the
% freedom to distribute copies of free software (and charge for this service
% if you wish), that you receive source code or can get it if you want it,
% that you can change the software or use pieces of it in new free programs;
% and that you know you can do these things.
%
% To protect your rights, we need to make restrictions that forbid anyone to
% deny you these rights or to ask you to surrender the rights.  These
% restrictions translate to certain responsibilities for you if you
% distribute copies of the software, or if you modify it.
%
% For example, if you distribute copies of such a program, whether gratis or
% for a fee, you must give the recipients all the rights that you have.  You
% must make sure that they, too, receive or can get the source code.  And
% you must show them these terms so they know their rights.
%
% We protect your rights with two steps: (1) copyright the software, and (2)
% offer you this license which gives you legal permission to copy,
% distribute and/or modify the software.
%
% Also, for each author's protection and ours, we want to make certain that
% everyone understands that there is no warranty for this free software.  If
% the software is modified by someone else and passed on, we want its
% recipients to know that what they have is not the original, so that any
% problems introduced by others will not reflect on the original authors'
% reputations.
%
% Finally, any free program is threatened constantly by software patents.
% We wish to avoid the danger that redistributors of a free program will
% individually obtain patent licenses, in effect making the program
% proprietary.  To prevent this, we have made it clear that any patent must
% be licensed for everyone's free use or not licensed at all.
%
% The precise terms and conditions for copying, distribution and
% modification follow.
%
% \begin{center}
% {\Large \sc Terms and Conditions For Copying, Distribution and
%   Modification}
% \end{center}
%
% \begin{enumerate}
% \item
% This License applies to any program or other work which contains a notice
% placed by the copyright holder saying it may be distributed under the
% terms of this General Public License.  The ``Program'', below, refers to
% any such program or work, and a ``work based on the Program'' means either
% the Program or any derivative work under copyright law: that is to say, a
% work containing the Program or a portion of it, either verbatim or with
% modifications and/or translated into another language.  (Hereinafter,
% translation is included without limitation in the term ``modification''.)
% Each licensee is addressed as ``you''.
%
% Activities other than copying, distribution and modification are not
% covered by this License; they are outside its scope.  The act of
% running the Program is not restricted, and the output from the Program
% is covered only if its contents constitute a work based on the
% Program (independent of having been made by running the Program).
% Whether that is true depends on what the Program does.
%
% \item You may copy and distribute verbatim copies of the Program's source
%   code as you receive it, in any medium, provided that you conspicuously
%   and appropriately publish on each copy an appropriate copyright notice
%   and disclaimer of warranty; keep intact all the notices that refer to
%   this License and to the absence of any warranty; and give any other
%   recipients of the Program a copy of this License along with the Program.
%
% You may charge a fee for the physical act of transferring a copy, and you
% may at your option offer warranty protection in exchange for a fee.
%
% \item
% You may modify your copy or copies of the Program or any portion
% of it, thus forming a work based on the Program, and copy and
% distribute such modifications or work under the terms of Section 1
% above, provided that you also meet all of these conditions:
%
% \begin{enumerate}
%
% \item
% You must cause the modified files to carry prominent notices stating that
% you changed the files and the date of any change.
%
% \item
% You must cause any work that you distribute or publish, that in
% whole or in part contains or is derived from the Program or any
% part thereof, to be licensed as a whole at no charge to all third
% parties under the terms of this License.
%
% \item
% If the modified program normally reads commands interactively
% when run, you must cause it, when started running for such
% interactive use in the most ordinary way, to print or display an
% announcement including an appropriate copyright notice and a
% notice that there is no warranty (or else, saying that you provide
% a warranty) and that users may redistribute the program under
% these conditions, and telling the user how to view a copy of this
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% does not normally print such an announcement, your work based on
% the Program is not required to print an announcement.)
%
% \end{enumerate}
%
%
% These requirements apply to the modified work as a whole.  If
% identifiable sections of that work are not derived from the Program,
% and can be reasonably considered independent and separate works in
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% distribute the same sections as part of a whole which is a work based
% on the Program, the distribution of the whole must be on the terms of
% this License, whose permissions for other licensees extend to the
% entire whole, and thus to each and every part regardless of who wrote it.
%
% Thus, it is not the intent of this section to claim rights or contest
% your rights to work written entirely by you; rather, the intent is to
% exercise the right to control the distribution of derivative or
% collective works based on the Program.
%
% In addition, mere aggregation of another work not based on the Program
% with the Program (or with a work based on the Program) on a volume of
% a storage or distribution medium does not bring the other work under
% the scope of this License.
%
% \item
% You may copy and distribute the Program (or a work based on it,
% under Section 2) in object code or executable form under the terms of
% Sections 1 and 2 above provided that you also do one of the following:
%
% \begin{enumerate}
%
% \item
%
% Accompany it with the complete corresponding machine-readable
% source code, which must be distributed under the terms of Sections
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%
% \item
%
% Accompany it with a written offer, valid for at least three
% years, to give any third party, for a charge no more than your
% cost of physically performing source distribution, a complete
% machine-readable copy of the corresponding source code, to be
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% customarily used for software interchange; or,
%
% \item
%
% Accompany it with the information you received as to the offer
% to distribute corresponding source code.  (This alternative is
% allowed only for noncommercial distribution and only if you
% received the program in object code or executable form with such
% an offer, in accord with Subsection b above.)
%
% \end{enumerate}
%
%
% The source code for a work means the preferred form of the work for
% making modifications to it.  For an executable work, complete source
% code means all the source code for all modules it contains, plus any
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% access to copy the source code from the same place counts as
% distribution of the source code, even though third parties are not
% compelled to copy the source along with the object code.
%
% \item
% You may not copy, modify, sublicense, or distribute the Program
% except as expressly provided under this License.  Any attempt
% otherwise to copy, modify, sublicense or distribute the Program is
% void, and will automatically terminate your rights under this License.
% However, parties who have received copies, or rights, from you under
% this License will not have their licenses terminated so long as such
% parties remain in full compliance.
%
% \item
% You are not required to accept this License, since you have not
% signed it.  However, nothing else grants you permission to modify or
% distribute the Program or its derivative works.  These actions are
% prohibited by law if you do not accept this License.  Therefore, by
% modifying or distributing the Program (or any work based on the
% Program), you indicate your acceptance of this License to do so, and
% all its terms and conditions for copying, distributing or modifying
% the Program or works based on it.
%
% \item
% Each time you redistribute the Program (or any work based on the
% Program), the recipient automatically receives a license from the
% original licensor to copy, distribute or modify the Program subject to
% these terms and conditions.  You may not impose any further
% restrictions on the recipients' exercise of the rights granted herein.
% You are not responsible for enforcing compliance by third parties to
% this License.
%
% \item
% If, as a consequence of a court judgment or allegation of patent
% infringement or for any other reason (not limited to patent issues),
% conditions are imposed on you (whether by court order, agreement or
% otherwise) that contradict the conditions of this License, they do not
% excuse you from the conditions of this License.  If you cannot
% distribute so as to satisfy simultaneously your obligations under this
% License and any other pertinent obligations, then as a consequence you
% may not distribute the Program at all.  For example, if a patent
% license would not permit royalty-free redistribution of the Program by
% all those who receive copies directly or indirectly through you, then
% the only way you could satisfy both it and this License would be to
% refrain entirely from distribution of the Program.
%
% If any portion of this section is held invalid or unenforceable under
% any particular circumstance, the balance of the section is intended to
% apply and the section as a whole is intended to apply in other
% circumstances.
%
% It is not the purpose of this section to induce you to infringe any
% patents or other property right claims or to contest validity of any
% such claims; this section has the sole purpose of protecting the
% integrity of the free software distribution system, which is
% implemented by public license practices.  Many people have made
% generous contributions to the wide range of software distributed
% through that system in reliance on consistent application of that
% system; it is up to the author/donor to decide if he or she is willing
% to distribute software through any other system and a licensee cannot
% impose that choice.
%
% This section is intended to make thoroughly clear what is believed to
% be a consequence of the rest of this License.
%
% \item
% If the distribution and/or use of the Program is restricted in
% certain countries either by patents or by copyrighted interfaces, the
% original copyright holder who places the Program under this License
% may add an explicit geographical distribution limitation excluding
% those countries, so that distribution is permitted only in or among
% countries not thus excluded.  In such case, this License incorporates
% the limitation as if written in the body of this License.
%
% \item
% The Free Software Foundation may publish revised and/or new versions
% of the General Public License from time to time.  Such new versions will
% be similar in spirit to the present version, but may differ in detail to
% address new problems or concerns.
%
% Each version is given a distinguishing version number.  If the Program
% specifies a version number of this License which applies to it and ``any
% later version'', you have the option of following the terms and conditions
% either of that version or of any later version published by the Free
% Software Foundation.  If the Program does not specify a version number of
% this License, you may choose any version ever published by the Free Software
% Foundation.
%
% \item
% If you wish to incorporate parts of the Program into other free
% programs whose distribution conditions are different, write to the author
% to ask for permission.  For software which is copyrighted by the Free
% Software Foundation, write to the Free Software Foundation; we sometimes
% make exceptions for this.  Our decision will be guided by the two goals
% of preserving the free status of all derivatives of our free software and
% of promoting the sharing and reuse of software generally.
%
% \begin{center}
% {\Large\sc
% No Warranty
% }
% \end{center}
%
% \item
% {\sc Because the program is licensed free of charge, there is no warranty
% for the program, to the extent permitted by applicable law.  Except when
% otherwise stated in writing the copyright holders and/or other parties
% provide the program ``as is'' without warranty of any kind, either expressed
% or implied, including, but not limited to, the implied warranties of
% merchantability and fitness for a particular purpose.  The entire risk as
% to the quality and performance of the program is with you.  Should the
% program prove defective, you assume the cost of all necessary servicing,
% repair or correction.}
%
% \item
% {\sc In no event unless required by applicable law or agreed to in writing
% will any copyright holder, or any other party who may modify and/or
% redistribute the program as permitted above, be liable to you for damages,
% including any general, special, incidental or consequential damages arising
% out of the use or inability to use the program (including but not limited
% to loss of data or data being rendered inaccurate or losses sustained by
% you or third parties or a failure of the program to operate with any other
% programs), even if such holder or other party has been advised of the
% possibility of such damages.}
%
% \end{enumerate}
%
%
% \begin{center}
% {\Large\sc End of Terms and Conditions}
% \end{center}
%
%
% \pagebreak[2]
%
% \section*{Appendix: How to Apply These Terms to Your New Programs}
%
% If you develop a new program, and you want it to be of the greatest
% possible use to the public, the best way to achieve this is to make it
% free software which everyone can redistribute and change under these
% terms.
%
%   To do so, attach the following notices to the program.  It is safest to
%   attach them to the start of each source file to most effectively convey
%   the exclusion of warranty; and each file should have at least the
%   ``copyright'' line and a pointer to where the full notice is found.
%
% \begin{quote}
% one line to give the program's name and a brief idea of what it does. \\
% Copyright (C) yyyy  name of author \\
%
% 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; if not, write to the Free Software
% Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
% \end{quote}
%
% Also add information on how to contact you by electronic and paper mail.
%
% If the program is interactive, make it output a short notice like this
% when it starts in an interactive mode:
%
% \begin{quote}
% Gnomovision version 69, Copyright (C) yyyy  name of author \\
% Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'. \\
% This is free software, and you are welcome to redistribute it
% under certain conditions; type `show c' for details.
% \end{quote}
%
%
% The hypothetical commands {\tt show w} and {\tt show c} should show the
% appropriate parts of the General Public License.  Of course, the commands
% you use may be called something other than {\tt show w} and {\tt show c};
% they could even be mouse-clicks or menu items---whatever suits your
% program.
%
% You should also get your employer (if you work as a programmer) or your
% school, if any, to sign a ``copyright disclaimer'' for the program, if
% necessary.  Here is a sample; alter the names:
%
% \begin{quote}
% Yoyodyne, Inc., hereby disclaims all copyright interest in the program \\
% `Gnomovision' (which makes passes at compilers) written by James Hacker. \\
%
% signature of Ty Coon, 1 April 1989 \\
% Ty Coon, President of Vice
% \end{quote}
%
%
% This General Public License does not permit incorporating your program
% into proprietary programs.  If your program is a subroutine library, you
% may consider it more useful to permit linking proprietary applications
% with the library.  If this is what you want to do, use the GNU Library
% General Public License instead of this License.
%
% \end{multicols}
% \end{minipage}
% \end{lrbox}
%
% \begin{center}
% \scalebox{0.33}{\usebox{\gpl}}
% \end{center}
%
% \Finale
\endinput