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%\iffalse
%
% (c) Copyright 2014-2021 Apostolos Syropoulos 
% This program can be redistributed and/or modified under the 
% terms of the LaTeX Project Public License Distributed from 
% http://www.latex-project.org/lppl.txt; either
% version 1.3c of the License, or any later version.
%  
% This work has the LPPL maintenance status `maintained'.
%
% Please report errors or suggestions for improvement to
%
%    Apostolos Syropoulos  (asyropoulos@yahoo.com)
%
%\fi
% \CheckSum{187}
% \iffalse This is a Metacomment
%
%<xespotcolor, >\ProvidesFile{xesporcolor.sty}
%
%<xespotcolor, > [2021/03/01 v2.1 Package `xespotcolor.sty']
%
%    \begin{macrocode}
%<*driver>
\documentclass{ltxdoc}
\GetFileInfo{xspotcolor.drv}
\usepackage{xltxtra}
\usepackage{fullpage}
\begin{document}
\setmainfont[Mapping=tex-text,Script=Greek]{Arno Pro}
\setmonofont{UM Typewriter}
\setsansfont[Mapping=tex-text]{GFS Neohellenic}
   \DocInput{xespotcolor.dtx}
\end{document}
%</driver>
%    \end{macrocode}
% \fi
%\MakeShortVerb{\|}
%\StopEventually{}
%\title{The \textsf{xespotcolor} package:\\ Spot Colors for \XeLaTeX\ \&\ \LaTeX}
%\author{Απόστολος Συρόπουλος\\
%        (Apostolos Syropoulos)\\
%        Xanthi, Greece\\
%        \texttt{asyropoulos@yahoo.com}}
% \date{2016/03/22\\updated 2021/03/01}
%\maketitle
% \begin{abstract}
% A spot color is one that is printed with its own ink. Typically, printers use spot colors
% in the production of books or other printed material. The \textsf{spotcolor} package
% by Jens Elstner is a first attempt to introduce the use of spot colors with pdfLaTeX.
% The \textsf{xespotcolor} package is a reimplementation of this package so to be usable with 
% \XeLaTeX\ and \LaTeX+\texttt{dvipdfmx}. As such, it has the same user interface and the same 
% capabilities.
%\end{abstract}
%
%\section{Introduction}
%
% Using spot colors with \XeLaTeX\ is very important since most printers use spot colors in the
% production of books and magazines. The \textsf{spotcolor} package makes it possible to use
% spot colors with pdf\LaTeX\ but it cannot be used with \XeLaTeX\ or \LaTeX. In what follows I first
% describe how to translate certain pdf\TeX\ code snippets into \XeTeX\ or \TeX+\texttt{dvipdfmx} 
% and then I present the code of the package. Thus one can view this text as a short tutorial on how to port 
% pdf\TeX\ code to \XeTeX\ or \TeX+\texttt{dvipdfmx} as well as a description of the functionality of the 
% \textsf{xespotcolor} package. Since the package is a port of a pdf\TeX\ package, it has the same functionality 
% as the original package. 
%
%
% \section{Porting pdf\TeX\ code to \XeTeX\ or \TeX+\texttt{dvipdfmx}}
%
% Translating pdf\TeX\ code, which adds PDF code to the output file, to \XeTeX\ or \TeX+\texttt{dvipdfmx} is not a 
% straightforward exercise  since pdf\TeX\ provides primitive commands that directly access and modify the structure of 
% the resulting PDF file. In the case of \XeTeX\ and \TeX\ one has to use |\special| commands that pass code to the driver. 
% In this particular case, I had to translate code snippets like the following one:
% \begin{center}
%  |1. \newcount\theCNTa                        |\\
%  |2. \newcount\theCNTb                        |\\
%  |3. \def\obj{ 0 R}%                          |\\
%  |4. \pdfobj{Raw PDF code 1}%                 |\\
%  |5. \theCNTa=\the\pdflastobj%                |\\
%  |6. \pdfobj{Raw PDF code \the\theCNTa \obj}% |\\  
%  |7. \theCNTb=\the\pdflastobj%                |\\
%  |8. \pdfrefobj\theCNTa%                      |\\
%  |9. \pdfrefobj\theCNTb%                      |\\
% \end{center}
% Here pdf\TeX\ creates two PDF objects, where the second contains a reference to the first one. The two counters
% defined in lines 1 and 2 are used to reference these two objects. The macro on line 3 is used to create code
% that references an object. The commands on lines 5 and 7 assign the object reference numbers and these numbers are
% used by the |\pdfrefobj| primitive. After some experimentation and some… Googling, I have found out that the following 
% \XeTeX\ code is a reasonable translation of the previous code snipper:
% \begin{center}
%  |\newcount\CNT                       |\\
%  |\newtoks\TOK                        |\\
%  |\TOK={@TOK \the\CNT}%               |\\
%  |\edef\A{\the\TOK Raw PDF code 1}%   |\\
%  |\edef\B{Raw PDF code \the\TOK}%     |\\  
%  |\special{pdf:obj \A}%               |\\
%  |\special{pdf:obj @TOKB\the\CNT \B}% |\\
%  |\advance\CNT by1%                   |\\
% \end{center}
% The two |\edef|initions are used to do the work done by |\pdfobj|. Note that here there I introduce only 
% one unique object and the first two lines define a counter and a token variable. The token variable uses
% the counter to create a unique identifier, which is passed to the driver. This way the driver will 
% create a number of different objects, if required to do so. The last two commands pass the raw PDF
% code and the unique identifier to the driver.
%
% The original package contains a definition identical to the following one:
% \begin{center}
% |\def\R#1{%                                                           |\\
% |   \edef\act{\noexpand\pdfpageresources={\the\pdfpageresources\space |\\
% |          /ColorSpace<<#1>>}}                                        |\\
% |   \act}                                                             |\\
% \end{center}
% The net effect of this command is to add a specific color space to the page resources of all subsequent pages.
% Unfortunately, when the following code is executed, it adds the particular color space to the current page only: 
% \begin{center}
%  |\def\R#1{%                                              |\\
%  |    \special{pdf:put @resources <</ColorSpace <<#1>>>>}}|\\
% \end{center} 
% In order to add the color space to all subsequent pages, I had to use the |\AddEverypageHook| command of
% package \textsf{everypage}. This command modifies the contents of the ship-out box by adding to it its argument. 
% And this is done for every single page. Also, one should note how the page resources are augmented by the two
% systems. In the case of \XeTeX\ we have to create a PDF dictionary that is merged with the current page resources,
% while in the case of pdf\TeX\ one just ``appends'' what is supposed to be included in the page resources dictionary.
% Let me now proceed with the description of the source code of the package.
%
% \section{The Source Code and Package Usage}
% The first part of the code is the identification part.
%    \begin{macrocode}
%<*xespotcolor>
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{xespotcolor}
          [2021/03/01 v.2.1, Package for adding Spot Color support to LaTeX/XeLaTeX.]
%    \end{macrocode}
% The package needs three packages in order to operate properly: the \textsf{graphics} package, the
% \textsf{everypage} package, and either the package \textsf{color} or the package \textsf{xcolor}.
% The later is necessary if one wants to use spot colors with \textsf{TikZ} and other packages that
% rely on package \textsf{xcolor}. Akira Kakuto has discovered that this package can be used with
% either \LaTeX\ or \XeLaTeX\ and the \texttt{dvipdfmx}/\texttt{xdvipdfmx} driver, respectively.
% However, in order to properly load the various packages it is necessary to know which typesetting
% engine is being used. A simple solution is to use the \textsf{iftex} package:
%    \begin{macrocode}
\RequirePackage{iftex}
%    \end{macrocode}
% Before proceeding it is also necessary to know if the package \textsf{xcolor} has been loaded
% (package \textsf{color} is loaded by default). The following command check if \textsf{xcolor}
% is loaded. If it is, it defines a new macro.
%    \begin{macrocode}
\@ifpackageloaded{xcolor}{\let\use@xcolor\relax}{}
%    \end{macrocode}
% Now we are ready to process the three package options: \texttt{hks}, \texttt{pantone}, and \texttt{xcolor}.
% Here we employ the same ``trick'': if an option is requested, we define a corresponding macro.
%    \begin{macrocode}
\DeclareOption{hks}{\let\use@hks\relax}
\DeclareOption{pantone}{\let\use@pantone\relax}
\DeclareOption{xcolor}{\let\use@xcolor\relax}
\ProcessOptions
%    \end{macrocode}
% The code that follows loads the remaining two packages. If macro |\use@xcolor| is not
% defined, then the package should load the \textsf{color} package; otherwise it should
% load the \textsf{xcolor} package. The two inner |\if|s are used to load properly the packages
% when \XeTeX\ or \TeX\ is used to typeset a document. In addition, to avoid unnecessary package
% loadings, there are some tests to make sure the packages are not loaded.
%    \begin{macrocode}
\ifx\use@xcolor\undefined
\ifxetex
   \@ifpackageloaded{graphics}{}{\RequirePackage[xetex]{graphics}}
   \@ifpackageloaded{color}{}\RequirePackage[xetex]{color}
\else
   \@ifpackageloaded{graphics}{}{\RequirePackage[dvipdfmx]{graphics}}
   \@ifpackageloaded{color}{}\RequirePackage{color}
\fi
\else
\ifxetex
   \@ifpackageloaded{graphics}{}{\RequirePackage[xetex]{graphics}}
   \@ifpackageloaded{xcolor}{}{\RequirePackage[xetex]{xcolor}}
\else
   \@ifpackageloaded{graphics}{}{\RequirePackage[dvipdfmx]{graphics}}
   \@ifpackageloaded{xcolor}{}{\RequirePackage{xcolor}}
\fi\fi
%    \end{macrocode}
% The following command should be executed only when using \textsf{TikZ} and/or \textsf{tcolorbox}. Thus, always 
% load this package after loading \textsf{TikZ} and/or \textsf{tcolorbox}. 
%    \begin{macrocode}
\@ifpackageloaded{tikz}{\global\pgf@sys@pdf@colorspaces@existsfalse}{}
\@ifpackageloaded{tcolorbox}{\global\pgf@sys@pdf@colorspaces@existsfalse}{}
%    \end{macrocode}
% The |\NewSpotColorSpace| command should be used to define a new color space for spot colors. The new color 
% space can be any imaginable word! This color space is the place where a new spot color will live. The  
% \texttt{hks} and  the \texttt{pantone} options create two color spaces where the corresponding colors live.
%    \begin{macrocode}
\def\NewSpotColorSpace#1{%
  \expandafter\newtoks\csname #1\endcsname%
  \csname #1\endcsname{}%
}
%    \end{macrocode}
% The |\AddSpotColor| macro should be used to introduce a new spot color. Thus it is one of the first commands 
% on should play with when using this package. This command takes four parameters---the name of a new color 
% space, which has been declared with |\NewSpotColorSpace|, the name of a new color, a name which will be 
% used internally, and a CMYK representation of the new color. For example, here is a typical use of this macro:
% \begin{center}
%|\AddSpotColor{NEWCS}{NEWCOLOR}{emerald\SpotSpace city}{0.83 0 0.04 30}|
% \end{center}
% CMYK tables usually specify the four color components using percentages, which must be ``translated'' to
% numbers between 0 and 1.
%
% Macro |\SpotSpace| is used to introduce blanks in names. According to the PDF standard a blank is denoted 
% by the character sequence |#20| and this is the reason why |\SpotSpace| is defined as follows:
%    \begin{macrocode}
\catcode`\#=12%
\def\SpotSpace{#20}
\catcode`\#=6%
%    \end{macrocode}
%The macro |\csgrab| is quite unsual---it takes two arguments and creates a sequence of them.
%    \begin{macrocode}
\gdef\csgrab#1#2{#2\expandafter{\the#2 #1}}%
%    \end{macrocode}
%Note that this command should never be used by an ordinary package user.
%
% The following variables are used in the definition of macro |\AddSpotColor|. Their functionality has been
% described in the previous section.
%    \begin{macrocode}
\newcount\colorprofilecnt
\newtoks\mycolorprofilename
%    \end{macrocode}
% Macro |\AddSpotColor| first defines a new color profile by assigning a value to |\mycolorprofilename|. The 
% name consists of the word |@mycolorprofile| followed by an integer. This name is used in the construction 
% of the corresponding PDF object.
%    \begin{macrocode}
\def\AddSpotColor#1#2#3#4{%
   \mycolorprofilename={@mycolorprofile\the\colorprofilecnt}%
%    \end{macrocode}
% The following two macros expand to PDF instructions that define the spot color. The PDF instructions are copied verbatim from 
% the original \textsf{spotcolor} package. 
%    \begin{macrocode}
   \edef\mycolorprofile{\the\mycolorprofilename 
           <</C0[0 0 0 0]/FunctionType 2/C1[#4]/Domain[0 1]/N 1>>}%
   \edef\mycolor{[/Separation/#3 /DeviceCMYK \the\mycolorprofilename]}%
%    \end{macrocode}
% The next two lines have been copied verbatim from the original macro definition.
%    \begin{macrocode}
   \edef\tempcs{/#2 \mycolor}%
   \expandafter\csgrab\expandafter{\tempcs}{\csname #1\endcsname}%
%    \end{macrocode}
% In the last part of the macro definition, the driver is instructed to build two objects which should 
% contain the definition of the new spot color. Note that here the macro specifies explicitly the object 
% reference for the second object.
%    \begin{macrocode}  
   \special{pdf:obj \mycolorprofile}% 
   \special{pdf:obj @myowncolor\the\colorprofilecnt \mycolor}%
%    \end{macrocode}
% Since all names must be distinct, the macro increments the value of the |\colorprofilecnt| counter by one.
%    \begin{macrocode}
   \advance\colorprofilecnt by1%
}
%    \end{macrocode}
%
% Command |\SetPageColorResource| is used by command |\SetPageColorSpace| to set the color space.
% The |\special| command below sets the page resources only for the current page. Since the color
% space should be visible to every subsequent page, initially I had opted to use command the |\AddEverypageHook| 
% command provided by the \textsf{everypage} package. However, since the latest version of \LaTeX\ defines
% hooks, I had to use the new \texttt{shipout/background} hook. 
%    \begin{macrocode}
\def\SetPageColorResource#1{%
   \AddToHook{shipout/background}{\put(1in,-1in){%
                \special{pdf:put @resources <</ColorSpace <<#1>>>>}}}%
}%
\def\SetPageColorSpace#1{%
   \expandafter\SetPageColorResource\expandafter{\the\csname #1\endcsname}%
}%
%    \end{macrocode}
% If a user wants to set a spot color as the default color, she should use the |\SpotColor| command:
%    \begin{macrocode}
\def\SpotColor#1#2{%
   \special{pdf:literal /#1 cs /#1 CS #2 sc #2 SC}%
   \aftergroup\reset@color%
}%
%    \end{macrocode}
% Suppose that a user wants to define a new spot color. Then, she has to issue a command like the
% following one:
% \begin{center}
% |\definecolor{Spots}{spotcolor}{SPCOLOR,1.0}|
% \end{center}
% Note that the second argument of this command must always be |spotcolor|, since this is the color
% model we are using. In addition, this command is meaningful only when
% one has defined a new color space, a new spot color using commands like the following ones:
%\begin{center}
%\begin{tabular}{l}
%|\NewSpotColorSpace{SPCOLORSPACE}|\\
%|\AddSpotColor{SPCOLORSPACE}{SPCOLOR}{Some\SpotSpace Name}{0.5 1.0 0.51 0}|\\
%|\SetPageColorSpace{SPCOLORSPACE}|\\
%\end{tabular}
%\end{center}
% Note that we must set the page color space!
%
% Depending on which color package is in use, different low-level commands are executed in order to 
% actually define the new color. These new commands are provided by this package. In particular, when the 
% \textsf{color} package is used, these new commands are the |\color@spotcolor| command and  |\c@lor@@spotcolor| 
% command. On the other hand, when using the \textsf{xcolor} package these new commands are the |\XC@mod@spotcolor| 
% command and the |\@@xespotcolordef@xspc| command.
% 
% If variable |\use@xcolor| is undefined, this means that the user has opted to use the \textsf{color}
% package. 
%    \begin{macrocode}
\ifx\use@xcolor\undefined
%    \end{macrocode}
% The code that follows has been taken and subsequently modified from file \texttt{xetex.def},
% which  is {\em not yet} part of the Standard LaTeX ``Graphics Bundle'' (see the documentation of
% the package's source code for more details). 
%    \begin{macrocode}
\def\color@spotcolor#1#2{\c@lor@@spotcolor#2\@@#1}
\def\c@lor@@spotcolor#1,#2\@@#3{%
   \c@lor@arg{#2}%
   \edef#3{spot #1 #2}%
}
%    \end{macrocode}
% The code that follows has been copied and subsequently modified from package
% \textsf{xspotcolor}. Obviously, the code uses the infrastructure provided by
% package \textsf{xcolor} to allow users to define new spot colors (see the 
% documentation of the source code of package \textsf{xcolor} for more details). 
%    \begin{macrocode}
\else
\XC@sdef\XC@mod@spotcolor{spotcolor}
\def\@@xespotcolordef@xspc#1,#2\@@{spot #1 #2}
\let\o@XC@definec@lor@xspc\XC@definec@lor
\def\XC@definec@lor[#1]#2[#3]#4#5%
{%
  \expandafter\ifx\csname XC@mod@#4\endcsname\XC@mod@spotcolor
    \expandafter\xdef\csname\string\color @#2\endcsname
    {\noexpand\xcolor@{}{\@@xespotcolordef@xspc#5\@@}{spotcolor}{#5}}%
   \else
    \o@XC@definec@lor@xspc[#1]{#2}[#3]{#4}{#5}%
  \fi
}%
%    \end{macrocode}
% Since \textsf{TikZ} is widely used today for drawing, the following commands are
% redefined to allow the use of spot colors in pictures created with this package.
%    \begin{macrocode}
\gdef\pgfsys@color@spotcolor@stroke#1#2{\special{pdf:literal /#1 CS #2 SC}}
\gdef\pgfsys@color@spotcolor@fill#1#2{\special{pdf:literal /#1 cs #2 sc}}
\gdef\pgfsys@color@spotcolor#1#2{\pgfsys@color@spotcolor@stroke{#1}{#2}%
                                 \pgfsys@color@spotcolor@fill{#1}{#2}}
\fi
%    \end{macrocode}
% If the \texttt{pantone} or the \texttt{hks} option have be specified, then the package loads the corresponding 
% color tables
%    \begin{macrocode}
\ifx\use@hks\undefined\else\input{spotcolorhks}\fi
\ifx\use@pantone\undefined\else\input{spotcolorpantone}\fi
%</xespotcolor>
%    \end{macrocode}
% \Finale
% \section{Simple Usage Example}
% The code that follows shows how one should use the package to create color drawings using Tikz.
% \begin{flushleft}
% |% First define a new color space|\\
% |\NewSpotColorSpace{MyPantone}|\\
% |% Now define real colors|\\
% |\AddSpotColor{MyPantone}{Blue}{Spot\SpotSpace Color\SpotSpace Blue}{0.92 0.24 0 0}|\\
% |\AddSpotColor{MyPantone}{Green}{Spot\SpotSpace Color\SpotSpace Green} {0.65 0 0.96 0}|\\
% |% Next we need to set the page color space|\\
% |\SetPageColorSpace{MyPantone}|\\
% |% Finally we can define colors!|\\
% |\definecolor{MyGreen}{spotcolor}{Green,0.5}|\\
% |\definecolor{MyBlue}{spotcolor}{Blue,0.5}|\\
% |% And this how we use these colors in drawings.|\\
% |\begin{tikzpicture}|\\ 
% |  \filldraw[color=MyGreen] (0.1,0.1) rectangle (1.9,0.9);|\\
% |  \draw[color=MyBlue, ultra thick] (0,0) rectangle (2,1);|\\
% |\end{tikzpicture}|\\
% \end{flushleft}
% \section*{Acknowledgements}
% I would like to thank Akira Kakuto for his comments and suggestions. Also, I would like to thank
% иеромонах Пантелеимон (Королев) [hieromonk Panteleimon] for his questions and testing.