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+% \iffalse meta-comment
+%
+%% File: l3color.dtx
+%
+% Copyright (C) 2017-2024 The LaTeX Project
+%
+% It may be distributed and/or modified under the conditions of the
+% LaTeX Project Public License (LPPL), either version 1.3c of this
+% license or (at your option) any later version. The latest version
+% of this license is in the file
+%
+% http://www.latex-project.org/lppl.txt
+%
+% This file is part of the "l3kernel bundle" (The Work in LPPL)
+% and all files in that bundle must be distributed together.
+%
+% -----------------------------------------------------------------------
+%
+% The development version of the bundle can be found at
+%
+% https://github.com/latex3/latex3
+%
+% for those people who are interested.
+%
+%<*driver>
+\documentclass[full]{l3doc}
+\begin{document}
+ \DocInput{\jobname.dtx}
+\end{document}
+%</driver>
+% \fi
+%
+% \title{^^A
+% The \pkg{l3color} module\\ Color support^^A
+% }
+%
+% \author{^^A
+% The \LaTeX{} Project\thanks
+% {^^A
+% E-mail:
+% \href{mailto:latex-team@latex-project.org}
+% {latex-team@latex-project.org}^^A
+% }^^A
+% }
+%
+% \date{Released 2024-04-11}
+%
+% \maketitle
+%
+% \begin{documentation}
+%
+% \section{Color in boxes}
+%
+% Controlling the color of text in boxes requires a small number of control
+% functions, so that the boxed material uses the color at the point where
+% it is set, rather than where it is used.
+%
+% \begin{function}[added = 2011-09-03]{\color_group_begin:, \color_group_end:}
+% \begin{syntax}
+% \cs{color_group_begin:}
+% \ldots
+% \cs{color_group_end:}
+% \end{syntax}
+% Creates a color group: one used to \enquote{trap} color settings.
+% This grouping is built in to for example \cs{hbox_set:Nn}.
+% \end{function}
+%
+% \begin{function}[added = 2011-09-03]{\color_ensure_current:}
+% \begin{syntax}
+% \cs{color_ensure_current:}
+% \end{syntax}
+% Ensures that material inside a box uses the foreground color
+% at the point where the box is set, rather than that in force when the
+% box is used. This function should usually be used within a
+% \cs{color_group_begin:} \ldots \cs{color_group_end:} group.
+% \end{function}
+%
+% \section{Color models}
+%
+% A color \emph{model} is a way to represent sets of colors. Different models
+% are particularly suitable for different output methods, \emph{e.g.}~screen
+% or print. Parameter-based models can describe a very large number of unique
+% colors, and have a varying number of \emph{axes} which define a color
+% space. In contrast, various proprietary models are available which define
+% \emph{spot} colors (more formally separations).
+%
+% Core models are used to pass color information to output; these are
+% \enquote{native} to \pkg{l3color}. Core models use real numbers in the range
+% $[0,1]$ to represent values. The core models supported here are
+% \begin{itemize}
+% \item \texttt{gray} Grayscale color, with a single axis running from
+% $0$ (fully black) to $1$ (fully white)
+% \item \texttt{rgb} Red-green-blue color, with three axes, one for each of
+% the components
+% \item \texttt{cmyk} Cyan-magenta-yellow-black color, with four axes, one for
+% each of the components
+% \end{itemize}
+%
+% There are also interface models: these are convenient for users but have
+% to be manipulated before storing/passing to the backend. Interface models
+% are primarily integer-based: see below for more detail. The supported
+% interface models are
+% \begin{itemize}
+% \item \texttt{Gray} Grayscale color, with a single axis running from
+% $0$ (fully black) to $15$ (fully white)
+% \item \texttt{hsb} Hue-saturation-brightness color, with three axes,all
+% real values in the range $[0,1]$ for hue saturation and brightness
+% \item \texttt{Hsb} Hue-saturation-brightness color, with three axes, integer
+% in the range $[0,360]$ for hue, real values in the range $[0,1]$ for
+% saturation and brightness
+% \item \texttt{HSB} Hue-saturation-brightness color, with three axes, integers
+% in the range $[0,240]$ for hue, saturation and brightness
+% \item \texttt{HTML} HTML format representation of RGB color given as a
+% single six-digit hexadecimal number
+% \item \texttt{RGB} Red-green-blue color, with three axes, one for each of
+% the components, values as integers from $0$ to $255$
+% \item \texttt{wave} Light wavelength, a real number in the range
+% $380$ to $780$ (nanometres)
+% \end{itemize}
+% All interface models are internally stored as |rgb|.
+%
+% Finally, there are a small number of models which are parsed to allow
+% data transfer from \pkg{xcolor} but which should not be used by end-users.
+% These are
+% \begin{itemize}
+% \item \texttt{cmy} Cyan-magenta-yellow color with three axes, one for
+% each of the components; converted to |cmyk|
+% \item \texttt{tHsb} \enquote{Tuned} hue-saturation-brightness color with three
+% axes, integer in the range $[0,360]$ for hue, real values in the range
+% $[0,1]$ for saturation and brightness; converted to |rgb| using the
+% standard tuning map defined by \pkg{xcolor}
+% \item \texttt{\&spot} Spot color tint with one value; treated as a gray
+% tint as spot color data is not available for extraction
+% \end{itemize}
+%
+% To allow parsing of data from \pkg{xcolor}, any leading model up the first
+% \texttt{:} will be discarded; the approach of selecting an internal form
+% for data is \emph{not} used in \pkg{l3color}.
+%
+% Additional models may be created to allow mixing of separation colors
+% with each other or with those from other models. See
+% Section~\ref{l3color:sec:new-models} for more detail of color support
+% for additional models.
+%
+% When color is selected by model, the \meta{values} given are specified as
+% a comma-separated list. The length of the list will therefore be determined
+% by the detail of the model involved.
+%
+% Color models (and interconversion) are complex, and more details are given
+% in the manual to the \LaTeXe{} \pkg{xcolor} package and in the
+% \emph{PostScript Language Reference Manual}, published by Addison--Wesley.
+%
+% \section{Color expressions}
+%
+% In addition to allowing specification of color by model and values,
+% \pkg{l3color} also supports color expressions. These are created
+% by combining one or more color names, with the amount of each specified
+% as a value in the range $0$--$100$. The value should be given between
+% |!| symbols in the expression. Thus for example
+% \begin{verbatim}
+% red!50!green
+% \end{verbatim}
+% is a mixture of $50\,\%$ red and $50\,\%$ green. A trailing value is
+% interpreted as implicitly followed by |!white|, and so
+% \begin{verbatim}
+% red!25
+% \end{verbatim}
+% specifies $25\,\%$ red mixed with $75\,\%$ white.
+%
+% Where the models for the mixed colors are different, the model of the first
+% color is used. Thus
+% \begin{verbatim}
+% red!50!cyan
+% \end{verbatim}
+% will result in a color specification using the |rgb| model, made up of
+% $50\,\%$ red and $50\,\%$ of cyan \emph{expressed in \texttt{rgb}}.
+% This may be important as color model interconversion is not exact.
+%
+% The one exception to the above is where the first model in an expression is
+% |gray|. In this case, the order of mixing is \enquote{swapped} internally, so
+% that for example
+% \begin{verbatim}
+% black!50!red
+% \end{verbatim}
+% has the same result as
+% \begin{verbatim}
+% red!50!black
+% \end{verbatim}
+% (the predefined colors |black| and |white| use the |gray| model).
+%
+% Where more than two colors are mixed in an expression, evaluation takes place
+% in a stepwise fashion. Thus in
+% \begin{verbatim}
+% cyan!50!magenta!10!yellow
+% \end{verbatim}
+% the sub-expression
+% \begin{verbatim}
+% cyan!50!magenta
+% \end{verbatim}
+% is first evaluated to give an intermediate color specification, before
+% the second step
+% \begin{verbatim}
+% <intermediate>!10!yellow
+% \end{verbatim}
+% where |<intermediate>| represents this transitory calculated value.
+%
+% Within a color expression, |.| may be used to represent the color active
+% for typesetting (the current color). This allows for example
+% \begin{verbatim}
+% .!50
+% \end{verbatim}
+% to mean a mixture of $50\,\%$ of current color with white.
+%
+% (Color expressions supported here are a subset of those provided by
+% the \LaTeXe{} \pkg{xcolor} package. At present, only such features as are
+% clearly useful have been added here.)
+%
+% \section{Named colors}
+%
+% Color names are stored in a single namespace, which makes them accessible
+% as part of color expressions. Whilst they are not reserved in a technical
+% sense, the names |black|, |white|, |red|, |green|, |blue|, |cyan|, |magenta|
+% and |yellow| have special meaning and should not be redefined. Color names
+% should be made up of letters, numbers and spaces only: other characters are
+% reserved for use in color expressions. In particular, |.| represents the
+% current color at the start of a color expression.
+%
+% \begin{function}{\color_set:nn}
+% \begin{syntax}
+% \cs{color_set:nn} \Arg{name} \Arg{color expression}
+% \end{syntax}
+% Evaluates the \meta{color expression} and stores the resulting
+% color specification as the \meta{name}.
+% \end{function}
+%
+% \begin{function}{\color_set:nnn}
+% \begin{syntax}
+% \cs{color_set:nnn} \Arg{name} \Arg{model(s)} \Arg{value(s)}
+% \end{syntax}
+% Stores the color specification equivalent to the \meta{model(s)} and
+% \meta{values} as the \meta{name}.
+% \end{function}
+%
+% \begin{function}{\color_set_eq:nn}
+% \begin{syntax}
+% \cs{color_set_eq:nn} \Arg{name1} \Arg{name2}
+% \end{syntax}
+% Copies the color specification in \meta{name2} to \meta{name1}. The
+% special name |.| may be used to represent the current color, allowing
+% it to be saved to a name.
+% \end{function}
+%
+% \begin{function}[EXP, pTF, added = 2022-08-12]{\color_if_exist:n}
+% \begin{syntax}
+% \cs{color_if_exist_p:n} \Arg{name}
+% \cs{color_if_exist:nTF} \Arg{name} \Arg{true code} \Arg{false code}
+% \end{syntax}
+% Tests whether \meta{name} is currently defined to provide a color
+% specification.
+% \end{function}
+%
+% \begin{function}[added = 2021-05-11]{\color_show:n, \color_log:n}
+% \begin{syntax}
+% \cs{color_show:n} \Arg{name}
+% \cs{color_log:n} \Arg{name}
+% \end{syntax}
+% Displays the color specification stored in the \meta{name} on the
+% terminal or log file.
+% \end{function}
+%
+% \section{Selecting colors}
+%
+% General selection of color is safe when split across pages: a stack is
+% used to ensure that the correct color is re-selected on the new page.
+%
+% These commands set the current color (|.|): other more specialised functions
+% such as fill and stroke selectors do \emph{not} adjust this value.
+%
+% \begin{function}{\color_select:n}
+% \begin{syntax}
+% \cs{color_select:n} \Arg{color expression}
+% \end{syntax}
+% Parses the \meta{color expression} and then activates the resulting
+% color specification for typeset material.
+% \end{function}
+%
+% \begin{function}{\color_select:nn}
+% \begin{syntax}
+% \cs{color_select:nn} \Arg{model(s)} \Arg{value(s)}
+% \end{syntax}
+% Activates the color specification equivalent to the \meta{model(s)} and
+% \meta{value(s)} for typeset material.
+% \end{function}
+%
+% \begin{variable}{\l_color_fixed_model_tl}
+% When this is set to a non-empty value, colors will be converted to
+% the specified model when they are selected. Note that included images
+% and similar are not influenced by this setting.
+% \end{variable}
+%
+% \section{Colors for fills and strokes}
+%
+% Colors for drawing operations and so forth are split into strokes and fills
+% (the latter may also be referred to as non-stroke color). The fill color is
+% used for text under normal circumstances. Depending on the backend, stroke
+% color may use a \emph{stack}, in which case it exhibits the same page breaking
+% behavior as general color. However, \texttt{dvips}/\texttt{dvisvgm} do not
+% support this, and so color will need to be contained within a scope, such
+% as \cs{draw_begin:}/\cs{draw_end:}.
+%
+% \begin{function}{\color_fill:n, \color_stroke:n}
+% \begin{syntax}
+% \cs{color_fill:n} \Arg{color expression}
+% \end{syntax}
+% Parses the \meta{color expression} and then activates the resulting
+% color specification for filling or stroking.
+% \end{function}
+%
+% \begin{function}{\color_fill:nn, \color_stroke:nn}
+% \begin{syntax}
+% \cs{color_fill:nn} \Arg{model(s)} \Arg{value(s)}
+% \end{syntax}
+% Activates the color specification equivalent to the \meta{model(s)} and
+% \meta{value(s)} for filling or stroking.
+% \end{function}
+%
+% \begin{variable}[module = color]{color.sc}
+% When using \texttt{dvips}, this PostScript variables hold the stroke color.
+% \end{variable}
+%
+% \subsection{Coloring math mode material}
+%
+% Coloring math mode material using \cs[no-index]{color_select:nn(n)} has some restrictions
+% and often leads to spacing issues and/or poor input syntax. Avoiding generating
+% \tn{mathord} atoms whilst coloring only those parts of the input which are
+% required needs careful handling. The functionality here covers this important
+% use case.
+%
+% \begin{function}[added = 2022-01-26]{\color_math:nn, \color_math:nnn}
+% \begin{syntax}
+% \cs{color_math:nn} \Arg{color expression}\Arg{content}
+% \cs{color_math:nnn} \Arg{model(s)} \Arg{value(s)} \Arg{content}
+% \end{syntax}
+% Works as for \cs[no-index]{color_select:n(n)} but applies color only to the math mode
+% \meta{content}. The function does not generate a group and the \meta{content}
+% therefore retains its math atom states. Sub/superscripts are also properly
+% handled.
+% \end{function}
+%
+% \begin{variable}[added = 2022-01-26]{\l_color_math_active_tl}
+% This list controls which tokens are considered as math active and
+% should therefore be replaced by their definition during searching for
+% sub/superscripts.
+% \end{variable}
+%
+% \section{Multiple color models}
+%
+% When selecting or setting a color with an explicit model, it is possible
+% to give values for more than one model at one time. This is particularly
+% useful where automated conversion between models does not give the desired
+% outcome. To do this, the list of models and list of values are both subdivided
+% using |/| characters (as for the similar function in \pkg{xcolor}). For
+% example, to save a color with explicit |cmyk| and |rgb| values, one could
+% use
+% \begin{verbatim}
+% \color_set:nnn { foo } { cmyk / rgb }
+% { 0.1 , 0.2 , 0.3 , 0.4 / 0.1, 0.2 , 0.3 }
+% \end{verbatim}
+% The manually-specified conversion will be used in preference to automated
+% calculation whenever the model(s) listed are used: both in expressions and
+% when a fixed model is active.
+%
+% Similarly, the same syntax can be applied to directly selecting a color.
+% \begin{verbatim}
+% \color_select:nn { cmyk / rgb }
+% { 0.1 , 0.2 , 0.3 , 0.4 / 0.1, 0.2 , 0.3 }
+% \end{verbatim}
+% Again, this list is used when a fixed model is active: the first entry is used
+% unless there is a fixed model matching one of the other entries.
+%
+% \section{Exporting color specifications}
+%
+% The major use of color expressions is in setting typesetting output, but there
+% are other places in which some form of color information is required. These
+% may need data in a different format or using a different model to the internal
+% representation. Thus a set of functions are available to export colors in
+% different formats.
+%
+% Valid export targets are
+% \begin{itemize}
+% \item \texttt{backend} Two brace groups: the first containing the
+% model, the second containing space-separated values appropriate
+% for the model; this is the format required by backend functions
+% of \pkg{expl3}
+% \item \texttt{comma-sep-cmyk} Comma-separated cyan-magenta-yellow-black
+% values
+% \item \texttt{comma-sep-rgb} Comma-separated red-green-blue values
+% suitable for use as a PDF annotation color
+% \item \texttt{HTML} Uppercase two-digit hexadecimal values, expressing
+% a red-green-blue color; the digits are \emph{not} separated
+% \item \texttt{space-sep-cmyk} Space-separated cyan-magenta-yellow-black
+% values
+% \item \texttt{space-sep-rgb} Space-separated red-green-blue values
+% suitable for use as a PDF annotation color
+% \end{itemize}
+%
+% \begin{function}{\color_export:nnN}
+% \begin{syntax}
+% \cs{color_export:nnN} \Arg{color expression} \Arg{format} \Arg{tl}
+% \end{syntax}
+% Parses the \meta{color expression} as described earlier,
+% then converts to the \meta{format} specified and assigns the data to the
+% \meta{tl}.
+% \end{function}
+%
+% \begin{function}{\color_export:nnnN}
+% \begin{syntax}
+% \cs{color_export:nnnN} \Arg{model} \Arg{value(s)} \Arg{format} \Arg{tl}
+% \end{syntax}
+% Expresses the combination of \meta{model} and \meta{value(s)} in an
+% internal representation, then converts to the \meta{format} specified and
+% assigns the data to the \meta{tl}.
+% \end{function}
+%
+% \section{Creating new color models}
+% \label{l3color:sec:new-models}
+%
+% Additional color models are required to support specialist workflows, for
+% example those involving separations (see
+% \url{https://helpx.adobe.com/indesign/using/spot-process-colors.html}
+% for details of the use of separations in print). Color models may be split
+% into families; for the standard device-based color models (\texttt{DeviceCMYK},
+% \texttt{DeviceRGB}, \texttt{DeviceGray}), these are synonymous. This
+% is not generally the case: see the PDF reference for more details. (Note that
+% \pkg{l3color} uses the shorter names \texttt{cmyk}, etc.)
+%
+% \begin{function}{\color_model_new:nnn}
+% \begin{syntax}
+% \cs{color_model_new:nnn} \Arg{model} \Arg{family} \Arg{params}
+% \end{syntax}
+% Creates a new \meta{model} which is derived from the color model \meta{family}.
+% The latter should be one of
+% \begin{itemize}
+% \item \texttt{DeviceN}
+% \item \texttt{ICCBased}
+% \item \texttt{Separation}
+% \end{itemize}
+% (The \meta{family} may be given in mixed case as-in the PDF reference:
+% internally, case of these strings is folded.)
+% Depending on the \meta{family}, one or more \meta{params} are mandatory or
+% optional.
+% \end{function}
+%
+% For a \texttt{Separation} space, there are three \emph{compulsory} keys.
+% \begin{itemize}
+% \item \texttt{name} The name of the Separation, for example the formal
+% name of a spot color ink. Such a \meta{name} may contain spaces, etc.,
+% which are not permitted in the \meta{model}.
+% \item \texttt{alternative-model} An alternative device colorspace, one of
+% \texttt{cmyk}, \texttt{rgb}, \texttt{gray} or \texttt{CIELAB}. The three
+% parameter-based models work as described above; see below for
+% details of CIELAB colors.
+% \item \texttt{alternative-values} A comma-separated list of values
+% appropriate to the \texttt{alternative-model}. This information is used by
+% the PDF application if the \texttt{Separation} is not available.
+% \end{itemize}
+%
+% CIELAB color separations are created using the
+% \texttt{alternative-model = CIELAB} setting. These colors must also have an
+% \texttt{illuminant} key, one of \texttt{a}, \texttt{c}, \texttt{e},
+% \texttt{d50}, \texttt{d55}, \texttt{d65} or \texttt{d75}. The
+% \texttt{alternative-values} in this case are the three parameters $L*$, $a*$
+% and $b*$ of the CIELAB model. Full details of this device-independent color
+% approach are given in the documentation to the \pkg{colorspace} package.
+%
+% CIELAB colors \emph{cannot} be converted into other device-dependent color
+% spaces, and as such, mixing can only occur if colors set up using the CIELAB
+% model are also given with an alternative parameter-based model. If that is
+% not the case, \pkg{l3color} will fallback to using black as the colorant in
+% any mixing.
+%
+% For a \texttt{DeviceN} space, there is one \emph{compulsory} key.
+% \begin{itemize}
+% \item \texttt{names} The names of the components of the \texttt{DeviceN}
+% space. Each should be either the \meta{name} of a \texttt{Separation} model,
+% a process color name (\texttt{cyan}, etc.) or the special name \texttt{none}.
+% \end{itemize}
+%
+% For a \texttt{ICCBased} space, there is one \emph{compulsory} key.
+% \begin{itemize}
+% \item \texttt{file} The name of the file containing the profile.
+% \end{itemize}
+%
+% \subsection{Color profiles}
+%
+% Color profiles are used to ensure color accuracy by linking to collaboration.
+% Applying a profile can be used to standardise color which is otherwise
+% device-dependence.
+%
+% \begin{function}[added = 2021-02-23]{\color_profile_apply:nn}
+% \begin{syntax}
+% \cs{color_profile_apply:nn} \Arg{profile} \Arg{model}
+% \end{syntax}
+% This function applies a \meta{profile} to one of the device \meta{models}.
+% The profile will then apply to all color of the selected \meta{model}. The
+% \meta{profile} should specify an ICC profile file. The \meta{model} has to
+% be one the standard device models: \texttt{cmyk}, \texttt{gray} or
+% \texttt{rgb}.
+% \end{function}
+%
+% \end{documentation}
+%
+% \begin{implementation}
+%
+% \section{\pkg{l3color} implementation}
+%
+% \begin{macrocode}
+%<*package>
+% \end{macrocode}
+%
+% \begin{macrocode}
+%<@@=color>
+% \end{macrocode}
+%
+% \subsection{Basics}
+%
+% \begin{variable}
+% {\l_@@_current_tl}
+% The color currently active for foreground (text, \emph{etc.}) material.
+% This is stored in the form of a color model followed by one or more
+% values. There are four pre-defined models, three of which take numerical
+% values in the range $[0,1]$:
+% \begin{itemize}
+% \item \texttt{gray \meta{gray}} Grayscale color with the \meta{gray}
+% value running from $0$ (fully black) to $1$ (fully white)
+% \item \texttt{cmyk \meta{cyan} \meta{magenta} \meta{yellow} \meta{black}}
+% \item \texttt{rgb \meta{red} \meta{green} \meta{blue}}
+% \end{itemize}
+% Notice that the value are separated by spaces. There is a fourth pre-defined
+% model using a string value and a numerical one:
+% \begin{itemize}
+% \item \texttt{spot \meta{name} \meta{tint}} A pre-defined spot color,
+% where the \meta{name} should be a pre-defined string color name and the
+% \meta{tint} should be in the range $[0,1]$.
+% \end{itemize}
+%
+% Additional models may be created to allow mixing of spot colors. The
+% number of data entries these require will depend on the number of
+% colors to be mixed.
+% \begin{texnote}
+% The content of \cs{l_@@_current_tl} comprises two brace groups, the
+% first containing the color model and the second containing the value(s)
+% applicable in that model.
+% \end{texnote}
+% \end{variable}
+%
+% \begin{macro}{\color_group_begin:, \color_group_end:}
+% Grouping for color is the same as using the basic \cs{group_begin:}
+% and \cs{group_end:} functions. However, for semantic reasons, they
+% are renamed here.
+% \begin{macrocode}
+\cs_new_eq:NN \color_group_begin: \group_begin:
+\cs_new_eq:NN \color_group_end: \group_end:
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\color_ensure_current:}
+% A driver-independent wrapper for setting the foreground color to the
+% current color \enquote{now}.
+% \begin{macrocode}
+\cs_new_protected:Npn \color_ensure_current:
+ { \@@_select:N \l_@@_current_tl }
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{variable}{\s_@@_stop}
+% Internal scan marks.
+% \begin{macrocode}
+\scan_new:N \s_@@_stop
+% \end{macrocode}
+% \end{variable}
+%
+% \begin{macro}{\@@_select:N, \@@_select_math:N}
+% \begin{macro}{\@@_select:nn}
+% Take an internal color specification and pass it to the driver. This code
+% is needed to ensure the current color but will also be used by the
+% higher-level material.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_select:N #1
+ {
+ \exp_after:wN \@@_select:nn #1
+ \group_insert_after:N \@@_backend_reset:
+ }
+\cs_new_protected:Npn \@@_select_math:N #1
+ { \exp_after:wN \@@_select:nn #1 }
+\cs_new_protected:Npn \@@_select:nn #1#2
+ { \use:c { @@_backend_select_ #1 :n } {#2} }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+%
+% \begin{variable}{\l_@@_current_tl}
+% The current color, with the model and
+% \begin{macrocode}
+\tl_new:N \l_@@_current_tl
+\tl_set:Nn \l_@@_current_tl { { gray } { 0 } }
+% \end{macrocode}
+% \end{variable}
+%
+% \subsection{Predefined color names}
+%
+% The ability to predefine colors with a name is a key part of this module and
+% means there has to be a method for storing the results. At first sight, it
+% seems natural to follow the usual \pkg{expl3} model and create a
+% \texttt{color} variable type for the process. That would then allow both
+% local and global colors, constant colors and the like. However, these names
+% need to be accessible in some form at the user level, for selection of colors
+% either simply by name or as part of a more complex expression. This does not
+% require that the full name is exposed but does require that they can be
+% looked up in a predictable way. As such, it is more useful to expose just the
+% color names as part of the interface, with the result that only local color
+% names can be created. (This is also seen for example in key creation in
+% \pkg{l3keys}.) As a result, color names are declarative (no \texttt{new}
+% functions).
+%
+% Since there is no need to manipulate colors \emph{en masse}, each is stored
+% in a two-part structure: a \texttt{prop} for the colors themselves, and a
+% \texttt{tl} for the default model for each color.
+%
+% \subsection{Setup}
+%
+% \begin{variable}{\l_@@_internal_int, \l_@@_internal_tl}
+% \begin{macrocode}
+\int_new:N \l_@@_internal_int
+\tl_new:N \l_@@_internal_tl
+% \end{macrocode}
+% \end{variable}
+%
+% \begin{variable}{\s_@@_mark}
+% Internal scan marks. \cs{s_@@_stop} is already defined in \pkg{l3color-base}.
+% \begin{macrocode}
+\scan_new:N \s_@@_mark
+% \end{macrocode}
+% \end{variable}
+%
+% \begin{variable}{\l_@@_ignore_error_bool}
+% Used to avoid issuing multiple errors if there is a change-of-model with
+% input container an error.
+% \begin{macrocode}
+\bool_new:N \l_@@_ignore_error_bool
+% \end{macrocode}
+% \end{variable}
+%
+% \subsection{Utility functions}
+%
+% \begin{macro}[pTF, EXP]{\color_if_exist:n}
+% A simple wrapper to avoid needing to have the lookup repeated in too many
+% places.To guard against a color created in a group, we need to test for
+% entries in the |prop|.
+% \begin{macrocode}
+\prg_new_conditional:Npnn \color_if_exist:n #1 { p , T, F, TF }
+ {
+ \prop_if_exist:cTF { l_@@_named_ #1 _prop }
+ {
+ \prop_if_empty:cTF { l_@@_named_ #1 _prop }
+ \prg_return_false:
+ \prg_return_true:
+ }
+ \prg_return_false:
+ }
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}[EXP]{\@@_model:N, \@@_values:N}
+% Simple abstractions.
+% \begin{macrocode}
+\cs_new:Npn \@@_model:N #1 { \exp_after:wN \use_i:nn #1 }
+\cs_new:Npn \@@_values:N #1 { \exp_after:wN \use_ii:nn #1 }
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\@@_extract:nNN, \@@_extract:VNN}
+% Recover the values for the standard model for a color.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_extract:nNN #1#2#3
+ {
+ \tl_set_eq:Nc #2 { l_@@_named_ #1 _tl }
+ \prop_get:cVN { l_@@_named_ #1 _prop } #2 #3
+ }
+\cs_generate_variant:Nn \@@_extract:nNN { V }
+% \end{macrocode}
+% \end{macro}
+%
+% \subsection{Model conversion}
+%
+% \begin{macro}{\@@_convert:nnN, \@@_convert:VVN}
+% \begin{macro}{\@@_convert:nnnN, \@@_convert:nVnN, \@@_convert:nnVN}
+% \begin{macro}[EXP]
+% {
+% \@@_convert_gray_gray:w
+% \@@_convert_gray_rgb:w
+% \@@_convert_gray_cmyk:w
+% \@@_convert_cmyk_gray:w
+% \@@_convert_cmyk_rgb:w
+% \@@_convert_cmyk_cmyk:w
+% \@@_convert_rgb_gray:w
+% \@@_convert_rgb_rgb:w
+% \@@_convert_rgb_cmyk:w
+% }
+% \begin{macro}[EXP]{\@@_convert_rgb_cmyk:nnn}
+% \begin{macro}[EXP]{\@@_convert_rgb_cmyk:nnnn}
+% Model conversion is carried out using standard formulae for base models,
+% as described in the manual for \pkg{xcolor} (see also the \emph{PostScript
+% Language Reference Manual}). For other models direct conversion might not
+% be defined, so we go through the fallback models if necessary.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_convert:nnN #1#2#3
+ { \@@_convert:nnVN {#1} {#2} #3 #3 }
+\cs_generate_variant:Nn \@@_convert:nnN { VV }
+\cs_generate_variant:Nn \exp_last_unbraced:Nf { c }
+\cs_new_protected:Npn \@@_convert:nnnN #1#2#3#4
+ {
+ \tl_set:Ne #4
+ {
+ \cs_if_exist_use:cTF { @@_convert_ #1 _ #2 :w }
+ { #3 \s_@@_stop }
+ {
+ \cs_if_exist:cTF { @@_convert_ \use:c { c_@@_fallback_ #1 _tl } _ #2 :w }
+ {
+ \exp_last_unbraced:cf
+ { @@_convert_ \use:c { c_@@_fallback_ #1 _tl } _ #2 :w }
+ { \use:c { @@_convert_ #1 _ \use:c { c_@@_fallback_ #1 _tl } :w } #3 \s_@@_stop }
+ \s_@@_stop
+ }
+ {
+ \exp_last_unbraced:cf
+ { @@_convert_ \use:c { c_@@_fallback_ #2 _tl } _ #2 :w }
+ {
+ \cs_if_exist_use:cTF { @@_convert_ #1 _ \use:c { c_@@_fallback_ #2 _tl } :w }
+ { #3 \s_@@_stop }
+ {
+ \exp_last_unbraced:cf
+ { @@_convert_ \use:c { c_@@_fallback_ #1 _tl } _ \use:c { c_@@_fallback_ #2 _tl } :w }
+ { \use:c { @@_convert_ #1 _ \use:c { c_@@_fallback_ #1 _tl } :w } #3 \s_@@_stop }
+ \s_@@_stop
+ }
+ }
+ \s_@@_stop
+ }
+ }
+ }
+ }
+\cs_generate_variant:Nn \@@_convert:nnnN { nV , nnV }
+\cs_new:Npn \@@_convert_gray_gray:w #1 \s_@@_stop
+ { #1 }
+\cs_new:Npn \@@_convert_gray_rgb:w #1 \s_@@_stop
+ { #1 ~ #1 ~ #1 }
+\cs_new:Npn \@@_convert_gray_cmyk:w #1 \s_@@_stop
+ { 0 ~ 0 ~ 0 ~ \fp_eval:n { 1 - #1 } }
+% \end{macrocode}
+% These rather odd values are based on \textsc{ntsc} television: the set are
+% used for the |cmyk| conversion.
+% \begin{macrocode}
+\cs_new:Npn \@@_convert_rgb_gray:w #1 ~ #2 ~ #3 \s_@@_stop
+ { \fp_eval:n { 0.3 * #1 + 0.59 * #2 + 0.11 * #3 } }
+\cs_new:Npn \@@_convert_rgb_rgb:w #1 \s_@@_stop
+ { #1 }
+% \end{macrocode}
+% The conversion from |rgb| to |cmyk| is the most complex: a two-step
+% procedure which requires \emph{black generation} and \emph{undercolor
+% removal} functions. The PostScript reference describes them as
+% device-dependent, but following \pkg{xcolor} we assume they are linear.
+% Moreover, as the likelihood of anyone using a non-unitary matrix here is
+% tiny, we simplify and treat those two concepts as no-ops. To allow code
+% sharing with parsing of |cmy| values, we have an intermediate function
+% here (\cs{@@_convert_rgb_cmyk:nnn}) which actually takes |cmy| values
+% as input.
+% \begin{macrocode}
+\cs_new:Npn \@@_convert_rgb_cmyk:w #1 ~ #2 ~ #3 \s_@@_stop
+ {
+ \exp_args:Neee \@@_convert_rgb_cmyk:nnn
+ { \fp_eval:n { 1 - #1 } }
+ { \fp_eval:n { 1 - #2 } }
+ { \fp_eval:n { 1 - #3 } }
+ }
+\cs_new:Npn \@@_convert_rgb_cmyk:nnn #1#2#3
+ {
+ \exp_args:Ne \@@_convert_rgb_cmyk:nnnn
+ { \fp_eval:n { min( #1, #2 , #3 ) } } {#1} {#2} {#3}
+ }
+\cs_new:Npn \@@_convert_rgb_cmyk:nnnn #1#2#3#4
+ {
+ \fp_eval:n { min ( 1 , max ( 0 , #2 - #1 ) ) } \c_space_tl
+ \fp_eval:n { min ( 1 , max ( 0 , #3 - #1 ) ) } \c_space_tl
+ \fp_eval:n { min ( 1 , max ( 0 , #4 - #1 ) ) } \c_space_tl
+ #1
+ }
+\cs_new:Npn \@@_convert_cmyk_gray:w #1 ~ #2 ~ #3 ~ #4 \s_@@_stop
+ { \fp_eval:n { 1 - min ( 1 , 0.3 * #1 + 0.59 * #2 + 0.11 * #3 + #4 ) } }
+\cs_new:Npn \@@_convert_cmyk_rgb:w #1 ~ #2 ~ #3 ~ #4 \s_@@_stop
+ {
+ \fp_eval:n { 1 - min ( 1 , #1 + #4 ) } \c_space_tl
+ \fp_eval:n { 1 - min ( 1 , #2 + #4 ) } \c_space_tl
+ \fp_eval:n { 1 - min ( 1 , #3 + #4 ) }
+ }
+\cs_new:Npn \@@_convert_cmyk_cmyk:w #1 \s_@@_stop
+ { #1 }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \subsection{Color expressions}
+%
+% \begin{variable}
+% {\l_@@_model_tl, \l_@@_value_tl, \l_@@_next_model_tl, \l_@@_next_value_tl}
+% Working space to store the color data whilst doing calculations: keeping
+% it on the stack is attractive but gets tricky (return is non-trivial).
+% \begin{macrocode}
+\tl_new:N \l_@@_model_tl
+\tl_new:N \l_@@_value_tl
+\tl_new:N \l_@@_next_model_tl
+\tl_new:N \l_@@_next_value_tl
+% \end{macrocode}
+% \end{variable}
+%
+% \begin{macro}{\@@_parse:nN}
+% \begin{macro}{\@@_parse_aux:nN}
+% \begin{macro}{\@@_parse_eq:Nn}
+% \begin{macro}{\@@_parse_eq:nNn}
+% \begin{macro}{\@@_parse:Nw}
+% \begin{macro}{\@@_parse_loop_init:Nnn}
+% \begin{macro}{\@@_parse_loop:w}
+% \begin{macro}{\@@_parse_loop_check:nn}
+% \begin{macro}{\@@_parse_loop:nn}
+% \begin{macro}{\@@_parse_gray:n, \@@_parse_std:n}
+% \begin{macro}{\@@_parse_break:w}
+% \begin{macro}{\@@_parse_end:}
+% \begin{macro}[EXP]{\@@_parse_mix:Nnnn, \@@_parse_mix:NVVn}
+% \begin{macro}[EXP]{\@@_parse_mix:nNnn}
+% \begin{macro}[EXP]
+% {
+% \@@_parse_mix_gray:nw ,
+% \@@_parse_mix_rgb:nw ,
+% \@@_parse_mix_cmyk:nw
+% }
+% The main function for parsing color expressions removes actives but
+% otherwise expands, then starts working through the expression itself.
+% At the end, we apply the payload.
+% \begin{macrocode}
+\cs_new_protected:Npe \@@_parse:nN #1#2
+ {
+ \tl_set:Ne \exp_not:c { l_@@_named_ . _tl }
+ { \exp_not:N \@@_model:N \exp_not:N \l_@@_current_tl }
+ \prop_put:NVe \exp_not:c { l_@@_named_ . _prop }
+ \exp_not:c { l_@@_named_ . _tl }
+ { \exp_not:N \@@_values:N \exp_not:N \l_@@_current_tl }
+ \exp_not:N \exp_args:Ne \exp_not:N \@@_parse_aux:nN
+ { \exp_not:N \tl_to_str:n {#1} } #2
+ }
+% \end{macrocode}
+% Before going to all of the effort of parsing an expression, these two
+% precursor functions look for a pre-defined name, either on its own or
+% with a trailing |!| (which is the same thing).
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_parse_aux:nN #1#2
+ {
+ \color_if_exist:nTF {#1}
+ { \@@_parse_set_eq:Nn #2 {#1} }
+ { \@@_parse:Nw #2#1 ! \s_@@_stop }
+ \@@_check_model:N #2
+ }
+\cs_new_protected:Npn \@@_parse_set_eq:Nn #1#2
+ {
+ \tl_if_empty:NTF \l_color_fixed_model_tl
+ { \exp_args:Nv \@@_parse_set_eq:nNn { l_@@_named_ #2 _tl } }
+ { \exp_args:NV \@@_parse_set_eq:nNn \l_color_fixed_model_tl }
+ #1 {#2}
+ }
+% \end{macrocode}
+% Here, we have to allow for the case where there is a fixed model:
+% that can't be swept up by generic conversion as we are dealing with a
+% named color.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_parse_set_eq:nNn #1#2#3
+ {
+ \prop_get:cnNTF
+ { l_@@_named_ #3 _prop } {#1}
+ \l_@@_value_tl
+ { \tl_set:Ne #2 { {#1} { \l_@@_value_tl } } }
+ {
+ \tl_set_eq:Nc \l_@@_model_tl { l_@@_named_ #3 _tl }
+ \prop_get:cVN { l_@@_named_ #3 _prop } \l_@@_model_tl
+ \l_@@_value_tl
+ \@@_convert:nnN
+ \l_@@_model_tl {#1} \l_@@_value_tl
+ \tl_set:Ne #2
+ {
+ {#1}
+ { \l_@@_value_tl }
+ }
+ }
+ }
+\cs_new_protected:Npn \@@_parse:Nw #1#2 ! #3 \s_@@_stop
+ {
+ \color_if_exist:nTF {#2}
+ {
+ \tl_if_blank:nTF {#3}
+ { \@@_parse_set_eq:Nn #1 {#2} }
+ { \@@_parse_loop_init:Nnn #1 {#2} {#3} }
+ }
+ {
+ \msg_error:nnn { color } { unknown-color } {#2}
+ \tl_set:Nn \l_@@_current_tl { { gray } { 0 } }
+ }
+ }
+% \end{macrocode}
+% Once we establish that a full parse is needed, the next job is to get the
+% detail of the first color. That will determine the model we use for the
+% calculation: splitting here makes checking that a bit easier.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_parse_loop_init:Nnn #1#2#3
+ {
+ \group_begin:
+ \@@_extract:nNN {#2} \l_@@_model_tl \l_@@_value_tl
+ \@@_parse_loop:w #3 ! ! ! ! \s_@@_stop
+ \tl_set:Ne \l_@@_internal_tl
+ { { \l_@@_model_tl } { \l_@@_value_tl } }
+ \exp_args:NNNV \group_end:
+ \tl_set:Nn #1 \l_@@_internal_tl
+ }
+% \end{macrocode}
+% This is the loop proper: there can be an open-ended set of colors to parse,
+% separated by |!| tokens. There are a few cases to look out for. At the end
+% of the expression and with we find a mix of $100$ then we simply skip the
+% next color entirely (we can't stop the loop as there might be a further
+% valid color to mix in). On the other hand, if we get a mix of $0$ then
+% drop everything so far and start again. There is also a trailing
+% |white| to \enquote{read in} if the final explicit data is a mix.
+% Those conditions are separate from actually looping, which is therefore
+% sorted out by checking if we have further data to process: in contrast
+% to \pkg{xcolor}, we don't allow |!!| so the test can be simplified.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_parse_loop:w #1 ! #2 ! #3 ! #4 ! #5 \s_@@_stop
+ {
+ \tl_if_blank:nF {#1}
+ {
+ \bool_lazy_and:nnTF
+ { \fp_compare_p:nNn {#1} > { 0 } }
+ { \fp_compare_p:nNn {#1} < { 100 } }
+ {
+ \use:e
+ {
+ \@@_parse_loop:nn {#1}
+ { \tl_if_blank:nTF {#2} { white } {#2} }
+ }
+ }
+ { \@@_parse_loop_check:nn {#1} {#2} }
+ }
+ \tl_if_blank:nF {#3}
+ { \@@_parse_loop:w #3 ! #4 ! #5 \s_@@_stop }
+ \@@_parse_end:
+ }
+% \end{macrocode}
+% As these are unusual cases, we accept slower performance here for clearer
+% code: check for the error conditions, handle the boundary cases after
+% that.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_parse_loop_check:nn #1#2
+ {
+ \bool_if:NF \l_@@_ignore_error_bool
+ {
+ \bool_lazy_or:nnT
+ { \fp_compare_p:nNn {#1} < { 0 } }
+ { \fp_compare_p:nNn {#1} > { 100 } }
+ { \msg_error:nnnnn { color } { out-of-range } {#1} { 0 } { 100 } }
+ }
+ \fp_compare:nNnF {#1} > \c_zero_fp
+ {
+ \tl_if_blank:nTF {#2}
+ { \@@_extract:nNN { white } }
+ { \@@_extract:nNN {#2} }
+ \l_@@_model_tl \l_@@_value_tl
+ }
+ }
+% \end{macrocode}
+% The \enquote{payload} of calculation in the loop first. If the model for
+% the upcoming color is different from that of the existing (partial) color,
+% convert the model. For |gray| the two are flipped round so that the outcome
+% is something with \enquote{real} color. We are then in a position to do the
+% actual calculation itself. The two auxiliaries here give us a way to break
+% the loop should an invalid name be found.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_parse_loop:nn #1#2
+ {
+ \color_if_exist:nTF {#2}
+ {
+ \@@_extract:nNN {#2} \l_@@_next_model_tl \l_@@_next_value_tl
+ \tl_if_eq:NNF \l_@@_model_tl \l_@@_next_model_tl
+ {
+ \str_if_eq:VnTF \l_@@_model_tl { gray }
+ { \@@_parse_gray:n {#2} }
+ { \@@_parse_std:n {#2} }
+ }
+ \tl_set:Ne \l_@@_value_tl
+ {
+ \@@_parse_mix:NVVn
+ \l_@@_model_tl \l_@@_value_tl \l_@@_next_value_tl {#1}
+ }
+ }
+ {
+ \msg_error:nnn { color } { unknown-color } {#2}
+ \@@_extract:nNN { black } \l_@@_model_tl \l_@@_value_tl
+ \@@_parse_break:w
+ }
+ }
+% \end{macrocode}
+% The \texttt{gray} model needs special handling: the models need to be
+% swapped: we do that using a dedicated function.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_parse_gray:n #1
+ {
+ \tl_set_eq:NN \l_@@_model_tl \l_@@_next_model_tl
+ \tl_set:Nn \l_@@_next_model_tl { gray }
+ \exp_args:NnV \@@_convert:nnN { gray } \l_@@_model_tl
+ \l_@@_value_tl
+ \prop_get:cVN { l_@@_named_ #1 _prop } \l_@@_model_tl
+ \l_@@_next_value_tl
+ }
+\cs_new_protected:Npn \@@_parse_std:n #1
+ {
+ \prop_get:cVNF { l_@@_named_ #1 _prop }
+ \l_@@_model_tl
+ \l_@@_next_value_tl
+ {
+ \@@_convert:VVN
+ \l_@@_next_model_tl
+ \l_@@_model_tl
+ \l_@@_next_value_tl
+ }
+ }
+\cs_new_protected:Npn \@@_parse_break:w #1 \@@_parse_end: { }
+\cs_new_protected:Npn \@@_parse_end: { }
+% \end{macrocode}
+% Do the vector arithmetic: mainly a question of shuffling input, along
+% with one pre-calculation to keep down the use of division.
+% \begin{macrocode}
+\cs_new:Npn \@@_parse_mix:Nnnn #1#2#3#4
+ {
+ \exp_args:Nf \@@_parse_mix:nNnn
+ { \fp_eval:n { #4 / 100 } }
+ #1 {#2} {#3}
+ }
+\cs_generate_variant:Nn \@@_parse_mix:Nnnn { NVV }
+\cs_new:Npn \@@_parse_mix:nNnn #1#2#3#4
+ {
+ \use:c { @@_parse_mix_ #2 :nw } {#1}
+ #3 \s_@@_mark #4 \s_@@_stop
+ }
+\cs_new:Npn \@@_parse_mix_gray:nw #1#2 \s_@@_mark #3 \s_@@_stop
+ { \fp_eval:n { #2 * #1 + #3 * ( 1 - #1 ) } }
+\cs_new:Npn \@@_parse_mix_rgb:nw
+ #1#2 ~ #3 ~ #4 \s_@@_mark #5 ~ #6 ~ #7 \s_@@_stop
+ {
+ \fp_eval:n { #2 * #1 + #5 * ( 1 - #1 ) } \c_space_tl
+ \fp_eval:n { #3 * #1 + #6 * ( 1 - #1 ) } \c_space_tl
+ \fp_eval:n { #4 * #1 + #7 * ( 1 - #1 ) }
+ }
+\cs_new:Npn \@@_parse_mix_cmyk:nw
+ #1#2 ~ #3 ~ #4 ~ #5 \s_@@_mark #6 ~ #7 ~ #8 ~ #9 \s_@@_stop
+ {
+ \fp_eval:n { #2 * #1 + #6 * ( 1 - #1 ) } \c_space_tl
+ \fp_eval:n { #3 * #1 + #7 * ( 1 - #1 ) } \c_space_tl
+ \fp_eval:n { #4 * #1 + #8 * ( 1 - #1 ) } \c_space_tl
+ \fp_eval:n { #5 * #1 + #9 * ( 1 - #1 ) }
+ }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}[EXP]
+% {
+% \@@_parse_model_gray:w, \@@_parse_model_rgb:w,
+% \@@_parse_model_cmyk:w
+% }
+% \begin{macro}[EXP]{\@@_parse_number:n}
+% \begin{macro}[EXP]{\@@_parse_number:w}
+% Turn the input into internal form, also tidying up the number quickly.
+% \begin{macrocode}
+\cs_new:Npn \@@_parse_model_gray:w #1 , #2 \s_@@_stop
+ { { gray } { \@@_parse_number:n {#1} } }
+\cs_new:Npn \@@_parse_model_rgb:w #1 , #2 , #3 , #4 \s_@@_stop
+ {
+ { rgb }
+ {
+ \@@_parse_number:n {#1} ~
+ \@@_parse_number:n {#2} ~
+ \@@_parse_number:n {#3}
+ }
+ }
+\cs_new:Npn \@@_parse_model_cmyk:w #1 , #2 , #3 , #4 , #5 \s_@@_stop
+ {
+ { cmyk }
+ {
+ \@@_parse_number:n {#1} ~
+ \@@_parse_number:n {#2} ~
+ \@@_parse_number:n {#3} ~
+ \@@_parse_number:n {#4}
+ }
+ }
+\cs_new:Npn \@@_parse_number:n #1
+ { \@@_parse_number:w #1 . 0 . \s_@@_stop }
+\cs_new:Npn \@@_parse_number:w #1 . #2 . #3 \s_@@_stop
+ { \tl_if_blank:nTF {#1} { 0 } {#1} . #2 }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}[EXP]
+% {
+% \@@_parse_model_Gray:w, \@@_parse_model_hsb:w,
+% \@@_parse_model_Hsb:w, \@@_parse_model_HSB:w,
+% \@@_parse_model_HTML:w, \@@_parse_model_RGB:w
+% }
+% \begin{macro}[EXP]{\@@_parse_model_hsb:nnn, \@@_parse_model_hsb_aux:nnn}
+% \begin{macro}[EXP]{\@@_parse_model_hsb:nnnn}
+% \begin{macro}[EXP]{\@@_parse_model_hsb:nnnnn}
+% \begin{macro}[EXP]
+% {
+% \@@_parse_model_hsb_0:nnnn ,
+% \@@_parse_model_hsb_1:nnnn ,
+% \@@_parse_model_hsb_2:nnnn ,
+% \@@_parse_model_hsb_3:nnnn ,
+% \@@_parse_model_hsb_4:nnnn ,
+% \@@_parse_model_hsb_5:nnnn
+% }
+% \begin{macro}[EXP]{\@@_parse_model_wave:w}
+% \begin{macro}[EXP]
+% {\@@_parse_model_wave_auxi:nn, \@@_parse_model_wave_auxii:nn}
+% \begin{macro}[EXP]{\@@_parse_model_wave_rho:n}
+% \begin{macrocode}
+\cs_new:Npn \@@_parse_model_Gray:w #1 , #2 \s_@@_stop
+ { { gray } { \fp_eval:n { #1 / 15 } } }
+\cs_new:Npn \@@_parse_model_hsb:w #1 , #2 , #3 , #4 \s_@@_stop
+ { \@@_parse_model_hsb:nnn {#1} {#2} {#3} }
+\cs_new:Npn \@@_parse_model_Hsb:w #1 , #2 , #3 , #4 \s_@@_stop
+ {
+ \exp_args:Ne \@@_parse_model_hsb:nnn { \fp_eval:n { #1 / 360 } }
+ {#2} {#3}
+ }
+% \end{macrocode}
+% The conversion here is non-trivial but is described at length
+% in the \pkg{xcolor} manual. For ease, we calculate the integer
+% and fractional parts of the hue first, then use them to work out the
+% possible values for $r$, $g$ and $b$ before putting them in the correct
+% places.
+% \begin{macrocode}
+\cs_new:Npn \@@_parse_model_hsb:nnn #1#2#3
+ {
+ { rgb }
+ {
+ \exp_args:Ne \@@_parse_model_hsb_aux:nnn
+ { \fp_eval:n { 6 * (#1) } } {#2} {#3}
+ }
+ }
+\cs_new:Npn \@@_parse_model_hsb_aux:nnn #1#2#3
+ {
+ \exp_args:Nee \@@_parse_model_hsb_aux:nnnn
+ { \fp_eval:n { floor(#1) } } { \fp_eval:n { #1 - floor(#1) } }
+ {#2} {#3}
+ }
+\cs_new:Npn \@@_parse_model_hsb_aux:nnnn #1#2#3#4
+ {
+ \use:e
+ {
+ \exp_not:N \@@_parse_model_hsb_aux:nnnnn
+ { \@@_parse_number:n {#4} }
+ { \fp_eval:n { round(#4 * (1 - #3) ,5) } }
+ { \fp_eval:n { round(#4 * ( 1 - #3 * #2 ) ,5) } }
+ { \fp_eval:n { round(#4 * ( 1 - #3 * (1 - #2) ) ,5) } }
+ {#1}
+ }
+ }
+\cs_new:Npn \@@_parse_model_hsb_aux:nnnnn #1#2#3#4#5
+ { \use:c { @@_parse_model_hsb_ #5 :nnnn } {#1} {#2} {#3} {#4} }
+\cs_new:cpn { @@_parse_model_hsb_0:nnnn } #1#2#3#4 { #1 ~ #4 ~ #2 }
+\cs_new:cpn { @@_parse_model_hsb_1:nnnn } #1#2#3#4 { #3 ~ #1 ~ #2 }
+\cs_new:cpn { @@_parse_model_hsb_2:nnnn } #1#2#3#4 { #2 ~ #1 ~ #4 }
+\cs_new:cpn { @@_parse_model_hsb_3:nnnn } #1#2#3#4 { #2 ~ #3 ~ #1 }
+\cs_new:cpn { @@_parse_model_hsb_4:nnnn } #1#2#3#4 { #4 ~ #2 ~ #1 }
+\cs_new:cpn { @@_parse_model_hsb_5:nnnn } #1#2#3#4 { #1 ~ #2 ~ #3 }
+\cs_new:cpn { @@_parse_model_hsb_6:nnnn } #1#2#3#4 { #1 ~ #2 ~ #2 }
+\cs_new:Npn \@@_parse_model_HSB:w #1 , #2 , #3 , #4 \s_@@_stop
+ {
+ \exp_args:Neee \@@_parse_model_hsb:nnn
+ { \fp_eval:n { round((#1) / 240,5) } }
+ { \fp_eval:n { round((#2) / 240,5) } }
+ { \fp_eval:n { round((#3) / 240,5) } }
+ }
+\cs_new:Npn \@@_parse_model_HTML:w #1 , #2 \s_@@_stop
+ { \@@_parse_model_HTML_aux:w #1 0 0 0 0 0 0 \s_@@_stop }
+\cs_new:Npn \@@_parse_model_HTML_aux:w #1#2#3#4#5#6#7 \s_@@_stop
+ {
+ { rgb }
+ {
+ \fp_eval:n { round(\int_from_hex:n {#1#2} / 255,5) } ~
+ \fp_eval:n { round(\int_from_hex:n {#3#4} / 255,5) } ~
+ \fp_eval:n { round(\int_from_hex:n {#5#6} / 255,5) }
+ }
+ }
+\cs_new:Npn \@@_parse_model_RGB:w #1 , #2 , #3 , #4 \s_@@_stop
+ {
+ { rgb }
+ {
+ \fp_eval:n { round((#1) / 255,5) } ~
+ \fp_eval:n { round((#2) / 255,5) } ~
+ \fp_eval:n { round((#3) / 255,5) }
+ }
+ }
+% \end{macrocode}
+% Following the description in the \pkg{xcolor} manual. As we always use |rgb|,
+% there is no need to find the sixth, we just pas the information straight
+% to the |hsb| auxiliary defined earlier.
+% \begin{macrocode}
+\cs_new:Npn \@@_parse_model_wave:w #1 , #2 \s_@@_stop
+ {
+ { rgb }
+ {
+ \fp_compare:nNnTF {#1} < { 420 }
+ { \@@_parse_model_wave_auxi:nn {#1} { 0.3 + 0.7 * (#1 - 380) / 40 }
+ }
+ {
+ \fp_compare:nNnTF {#1} > { 700 }
+ { \@@_parse_model_wave_auxi:nn {#1} { 0.3 + 0.7 * (#1 - 780) / -80 } }
+ { \@@_parse_model_wave_auxi:nn {#1} { 1 } }
+ }
+ }
+ }
+\cs_new:Npn \@@_parse_model_wave_auxi:nn #1#2
+ {
+ \fp_compare:nNnTF {#1} < { 440 }
+ {
+ \@@_parse_model_wave_auxii:nn
+ { 4 + \@@_parse_model_wave_rho:n { (#1 - 440) / -60 } }
+ {#2}
+ }
+ {
+ \fp_compare:nNnTF {#1} < { 490 }
+ {
+ \@@_parse_model_wave_auxii:nn
+ { 4 - \@@_parse_model_wave_rho:n { (#1 - 440) / 50 } }
+ {#2}
+ }
+ {
+ \fp_compare:nNnTF {#1} < { 510 }
+ {
+ \@@_parse_model_wave_auxii:nn
+ { 2 + \@@_parse_model_wave_rho:n { (#1 - 510) / -20 } }
+ {#2}
+ }
+ {
+ \fp_compare:nNnTF {#1} < { 580 }
+ {
+ \@@_parse_model_wave_auxii:nn
+ { 2 - \@@_parse_model_wave_rho:n { (#1 - 510) / 70 } }
+ {#2}
+ }
+ {
+ \fp_compare:nNnTF {#1} < { 645 }
+ {
+ \@@_parse_model_wave_auxii:nn
+ { \@@_parse_model_wave_rho:n { (#1 - 645) / -65 } }
+ {#2}
+ }
+ { \@@_parse_model_wave_auxii:nn { 0 } {#2} }
+ }
+ }
+ }
+ }
+ }
+\cs_new:Npn \@@_parse_model_wave_auxii:nn #1#2
+ {
+ \exp_args:Neee \@@_parse_model_hsb_aux:nnn
+ { \fp_eval:n {#1} }
+ { 1 }
+ { \@@_parse_model_wave_rho:n {#2} }
+ }
+\cs_new:Npn \@@_parse_model_wave_rho:n #1
+ { \fp_eval:n { min(1, max(0,#1) ) } }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}{\@@_parse_model_cmy:w}
+% Simply pass data to the conversion functions.
+% \begin{macrocode}
+\cs_new:Npn \@@_parse_model_cmy:w #1 , #2 , #3 , #4 \s_@@_stop
+ {
+ { cmyk }
+ { \@@_convert_rgb_cmyk:nnn {#1} {#2} {#3} }
+ }
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\@@_parse_model_tHsb:w}
+% \begin{macro}{\@@_parse_model_tHsb:n}
+% \begin{macro}{\@@_parse_model_tHsb:nw}
+% There are three stages to the process here: bring the |tH| argument into
+% the normal range, divide through to get to |hsb| and finally convert that
+% to |rgb|. The final stage can be delegated to the parsing function for
+% |hsb|, and the conversion from |Hsb| to |hsb| is trivial, so the main focus
+% here is the first stage. We use a simple expandable loop to do the work,
+% and we implement the equation given in the \pkg{xcolor} manual
+% (number~85 there) as a simple expression.
+% \begin{macrocode}
+\cs_new:Npn \@@_parse_model_tHsb:w #1 , #2 , #3 , #4 \s_@@_stop
+ {
+ \exp_args:Ne \@@_parse_model_hsb:nnn
+ { \@@_parse_model_tHsb:n {#1} } {#2} {#3}
+ }
+\cs_new:Npn \@@_parse_model_tHsb:n #1
+ {
+ \@@_parse_model_tHsb:nw {#1}
+ 0 , 0 ;
+ 60 , 30 ;
+ 120 , 60 ;
+ 180 , 120 ;
+ 210 , 180 ;
+ 240 , 240 ;
+ 360 , 360 ;
+ \q_recursion_tail , ;
+ \q_recursion_stop
+ }
+\cs_new:Npn \@@_parse_model_tHsb:nw #1 #2 , #3 ; #4 , #5 ;
+ {
+ \quark_if_recursion_tail_stop_do:nn {#4} { 0 }
+ \fp_compare:nNnTF {#1} > {#4}
+ { \@@_parse_model_tHsb:nw {#1} #4 , #5 ; }
+ {
+ \use_i_delimit_by_q_recursion_stop:nw
+ { \fp_eval:n { ((#1 - #2) / (#4 - #2) * (#5 - #3) + #3) / 360 } }
+ }
+ }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}{\@@_parse_model_&spot:w}
+% We cannot extract data here from that passed by \pkg{xcolor}, so
+% we fall back on a black tint.
+% \begin{macrocode}
+\cs_new:cpn { @@_parse_model_&spot:w } #1 , #2 \s_@@_stop
+ { { gray } { #1 } }
+% \end{macrocode}
+% \end{macro}
+%
+% \subsection{Selecting colors (and color models)}
+%
+% \begin{variable}{\l_color_fixed_model_tl}
+% For selecting a single fixed model.
+% \begin{macrocode}
+\tl_new:N \l_color_fixed_model_tl
+% \end{macrocode}
+% \end{variable}
+%
+% \begin{macro}{\@@_check_model:N}
+% \begin{macro}{\@@_check_model:nn}
+% Check that the model in use is the one required.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_check_model:N #1
+ {
+ \tl_if_empty:NF \l_color_fixed_model_tl
+ {
+ \exp_after:wN \@@_check_model:nn #1
+ \tl_if_eq:NNF \l_@@_model_tl \l_color_fixed_model_tl
+ {
+ \@@_convert:VVN \l_@@_model_tl \l_color_fixed_model_tl
+ \l_@@_value_tl
+ }
+ \tl_set:Ne #1
+ { { \l_color_fixed_model_tl } { \l_@@_value_tl } }
+ }
+ }
+\cs_new_protected:Npn \@@_check_model:nn #1#2
+ {
+ \tl_set:Nn \l_@@_model_tl {#1}
+ \tl_set:Nn \l_@@_value_tl {#2}
+ }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}{\@@_finalise_current:}
+% A backend-neutral location for \enquote{last minute} manipulations before
+% handing off to the backend code. We set the special |.| syntax here: this
+% will therefore always be available. The finalisation is separate from the
+% main function so it can also be applied to \emph{e.g.}~page color.
+% \begin{macrocode}
+\cs_new_protected:Npe \@@_finalise_current:
+ {
+ \tl_set:Ne \exp_not:c { l_@@_named_ . _tl }
+ { \exp_not:N \@@_model:N \exp_not:N \l_@@_current_tl }
+ \prop_clear:N \exp_not:c { l_@@_named_ . _prop }
+ \prop_put:NVe \exp_not:c { l_@@_named_ . _prop }
+ \exp_not:c { l_@@_named_ . _tl }
+ { \exp_not:N \@@_values:N \exp_not:N \l_@@_current_tl }
+ }
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\color_select:n}
+% \begin{macro}{\color_select:nn}
+% \begin{macro}{\@@_select_main:Nw, \@@_select_loop:Nw}
+% \begin{macro}{\@@_select:nnN}
+% \begin{macro}{\@@_select_swap:Nnn}
+% Parse the input expressions then get the backend to actually activate
+% them. The main complexity here is the need to check through multiple models.
+% That is done \enquote{locally} here as the approach is subtly different to
+% when different models are being stored.
+% \begin{macrocode}
+\cs_new_protected:Npn \color_select:n #1
+ {
+ \@@_parse:nN {#1} \l_@@_current_tl
+ \@@_finalise_current:
+ \@@_select:N \l_@@_current_tl
+ }
+\cs_new_protected:Npn \color_select:nn #1#2
+ {
+ \@@_select_main:Nw \l_@@_current_tl
+ #1 / / \s_@@_mark #2 / / \s_@@_stop
+ \@@_finalise_current:
+ \@@_select:N \l_@@_current_tl
+ }
+% \end{macrocode}
+% If the first color model is the fixed one, or if there is no fixed
+% model, we don't need most of the data: just set up and apply the backend
+% function.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_select_main:Nw
+ #1 #2 / #3 / #4 \s_@@_mark #5 / #6 / #7 \s_@@_stop
+ {
+ \@@_select:nnN {#2} {#5} #1
+ \bool_lazy_or:nnF
+ { \tl_if_empty_p:N \l_color_fixed_model_tl }
+ { \str_if_eq_p:nV {#2} \l_color_fixed_model_tl }
+ { \@@_select_loop:Nw #1 #3 / #4 \s_@@_mark #6 / #7 \s_@@_stop }
+ }
+% \end{macrocode}
+% If a fixed model applies, we need to check each possible value in order.
+% If there is no hit at all, fall back on the generic formula-based
+% interchange.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_select_loop:Nw
+ #1 #2 / #3 \s_@@_mark #4 / #5 \s_@@_stop
+ {
+ \str_if_eq:nVTF {#2} \l_color_fixed_model_tl
+ { \@@_select:nnN {#2} {#4} #1 }
+ {
+ \tl_if_blank:nTF {#2}
+ { \exp_after:wN \@@_select_swap:Nnn \exp_after:wN #1 #1 }
+ { \@@_select_loop:Nw #1 #3 \s_@@_mark #5 \s_@@_stop }
+ }
+ }
+\cs_new_protected:Npn \@@_select:nnN #1#2#3
+ {
+ \cs_if_exist:cTF { @@_parse_model_ #1 :w }
+ {
+ \tl_set:Ne #3
+ { \use:c { @@_parse_model_ #1 :w } #2 , 0 , 0 , 0 , 0 \s_@@_stop }
+ }
+ { \msg_error:nnn { color } { unknown-model } {#1} }
+ }
+\cs_new_protected:Npn \@@_select_swap:Nnn #1#2#3
+ {
+ \@@_convert:nVnN {#2} \l_color_fixed_model_tl {#3} \l_@@_value_tl
+ \tl_set:Ne #1
+ { { \l_color_fixed_model_tl } { \l_@@_value_tl } }
+ }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \subsection{Math color}
+%
+% The approach here is the same as for the \LaTeXe{} \cs{mathcolor} command,
+% but as we are working at the \pkg{expl3} level we can make some minor
+% changes.
+%
+% \begin{macro}{\l_color_math_active_tl}
+% Tokens representing active sub/superscripts.
+% \begin{macrocode}
+\tl_new:N \l_color_math_active_tl
+\tl_set:Nn \l_color_math_active_tl { ' }
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\g_@@_math_seq}
+% Not all engines have multiple color stacks, and at the same time we are
+% not expecting breaking within a colored math fragment. So we track the
+% color stack ourselves.
+% \begin{macrocode}
+\seq_new:N \g_@@_math_seq
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\color_math:nn}
+% \begin{macro}{\color_math:nnn}
+% \begin{macro}{\@@_math:nn}
+% The basic set up here is relatively simple: store the current color,
+% parse the new color as-normal, then switch color before inserting the
+% tokens we are asked to change. The tricky part is right at the end,
+% handling the reset.
+% \begin{macrocode}
+\cs_new_protected:Npn \color_math:nn #1#2
+ {
+ \@@_math:nn {#2}
+ { \@@_parse:nN {#1} \l_@@_current_tl }
+ }
+\cs_new_protected:Npn \color_math:nnn #1#2#3
+ {
+ \@@_math:nn {#3}
+ {
+ \@@_select_main:Nw \l_@@_current_tl
+ #1 / / \s_@@_mark #2 / / \s_@@_stop
+ }
+ }
+\cs_new_protected:Npn \@@_math:nn #1#2
+ {
+ \seq_gpush:NV \g_@@_math_seq \l_@@_current_tl
+ #2
+ \@@_select_math:N \l_@@_current_tl
+ #1
+ \@@_math_scan:w
+ }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}
+% {
+% \@@_math_scan:w ,
+% \@@_math_scan_auxi: ,
+% \@@_math_scan_auxii: ,
+% \@@_math_scan_end:
+% }
+% The complication when changing the color back is due to the fact
+% that the \cs{color_math:nn(n)} may be followed by \verb=^= or \verb=_=
+% or the hidden superscript (for example \texttt{'}) and its argument may
+% end in a \tn{mathop} in which case the sub- and superscripts may be
+% attached as \cs{limits} instead of after the material. All cases
+% need separate treatment. To avoid repeatedly collecting the same
+% token, we first check for an alignment tab: assuming we don't have
+% one of those, we can \enquote{recycle} \cs{l_peek_token} safely.
+% As we have an explicit \cs{c_alignment_token}, there needs to be
+% an align-safe group present.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_math_scan:w
+ {
+ \peek_remove_filler:n
+ {
+ \group_align_safe_begin:
+ \peek_catcode:NTF \c_alignment_token
+ {
+ \group_align_safe_end:
+ \@@_math_scan_end:
+ }
+ {
+ \group_align_safe_end:
+ \@@_math_scan_auxi:
+ }
+ }
+ }
+% \end{macrocode}
+% Dealing with literal |_| and |^| is easy, and as we have exactly two cases,
+% we can hard-code this. We use a hard-coded list for limits: these are all
+% primitives. The \cs{use_none:n} here also removes the test token so it is
+% left just in the right place.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_math_scan_auxi:
+ {
+ \token_case_catcode:NnTF \l_peek_token
+ {
+ \c_math_subscript_token { }
+ \c_math_superscript_token { }
+ }
+ { \@@_math_scripts:Nw }
+ {
+ \token_case_meaning:NnTF \l_peek_token
+ {
+ \tex_limits:D { \tex_limits:D }
+ \tex_nolimits:D { \tex_nolimits:D }
+ \tex_displaylimits:D { \tex_displaylimits:D }
+ }
+ { \@@_math_scan:w \use_none:n }
+ { \@@_math_scan_auxii: }
+ }
+ }
+% \end{macrocode}
+% The one final case to handle is math-active tokens, most obviously
+% \texttt{'}, as these won't be covered earlier.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_math_scan_auxii:
+ {
+ \tl_map_inline:Nn \l_color_math_active_tl
+ {
+ \token_if_eq_meaning:NNT \l_peek_token ##1
+ {
+ \tl_map_break:n
+ {
+ \use_i:nn
+ { \@@_math_scan_auxiii:N ##1 }
+ }
+ }
+ \@@_math_scan_end:
+ }
+ }
+\cs_new_protected:Npn \@@_math_scan_auxiii:N #1
+ {
+ \exp_after:wN \exp_after:wN \exp_after:wN \@@_math_scan:w
+ \char_generate:nn { `#1 } { 13 }
+ }
+\cs_new_protected:Npn \@@_math_scan_end:
+ {
+ \@@_backend_reset:
+ \seq_gpop:NN \g_@@_math_seq \l_@@_current_tl
+ }
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\@@_math_scripts:Nw}
+% \begin{macro}{\@@_math_script_aux:N}
+% The tricky part of handling sub and superscripts is that we have
+% to reset color to the one that is on the stack but reset it back
+% to what it was before to allow for cases like
+% \begin{verbatim}
+% \[ \color_math:n { red } { a + \sum } _ { i = 1 } ^ { n } \]
+% \end{verbatim}
+% Here, \TeX{} constructs a \cs{vbox} stacking subscript, summation
+% sign, and superscript. So technically the superscript comes first
+% and the \cs{sum} that should get colored red is the middle.
+%
+% The approach here is to set up a brace group immediately after the
+% script token, then to set the color appropriately in that argument.
+% We need an extra group to keep the color contained, and as we
+% need to allow for an explicit closing brace in the source, the
+% inner group also is a brace one rather than \cs{group_begin:}-based.
+% At the end of the outer group we need to insert \cs{@@_math_scan:w}
+% to continue the search for a second script token.
+%
+% Notice that here we \emph{don't} need to use the math-specific
+% color selector as we can allow the
+% |\group_insert_after:N \@@_backend_reset:| to operate normally.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_math_scripts:Nw #1
+ {
+ #1
+ \c_group_begin_token
+ \c_group_begin_token
+ \seq_get:NN \g_@@_math_seq \l_@@_current_tl
+ \@@_select:N \l_@@_current_tl
+ \group_insert_after:N \c_group_end_token
+ \group_insert_after:N \@@_math_scan:w
+ \peek_remove_filler:n
+ {
+ \peek_catcode_remove:NF \c_group_begin_token
+ { \@@_math_script_aux:N }
+ }
+ }
+% \end{macrocode}
+% Deal with the case where we do not have an explicit brace pair in the
+% source.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_math_script_aux:N #1 { #1 \c_group_end_token }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+%
+% \subsection{Fill and stroke color}
+%
+% \begin{macro}{\color_fill:n, \color_stroke:n}
+% \begin{macro}{\color_fill:nn, \color_stroke:nn}
+% \begin{macro}{\@@_draw:nnn}
+% \begin{macrocode}
+\cs_new_protected:Npn \color_fill:n #1
+ {
+ \@@_parse:nN {#1} \l_@@_current_tl
+ \exp_after:wN \@@_draw:nnn \l_@@_current_tl { fill }
+ }
+\cs_new_protected:Npn \color_stroke:n #1
+ {
+ \@@_parse:nN {#1} \l_@@_current_tl
+ \exp_after:wN \@@_draw:nnn \l_@@_current_tl { stroke }
+ }
+\cs_new_protected:Npn \color_fill:nn #1#2
+ {
+ \@@_select_main:Nw \l_@@_current_tl
+ #1 / / \s_@@_mark #2 / / \s_@@_stop
+ \exp_after:wN \@@_draw:nnn \l_@@_current_tl { fill }
+ }
+\cs_new_protected:Npn \color_stroke:nn #1#2
+ {
+ \@@_select_main:Nw \l_@@_current_tl
+ #1 / / \s_@@_mark #2 / / \s_@@_stop
+ \exp_after:wN \@@_draw:nnn \l_@@_current_tl { stroke }
+ }
+\cs_new_protected:Npn \@@_draw:nnn #1#2#3
+ {
+ \use:c { @@_backend_ #3 _ #1 :n } {#2}
+ \exp_args:Nc \group_insert_after:N { @@_backend_ #3 _ reset: }
+ }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \subsection{Defining named colors}
+%
+% \begin{variable}{\l_@@_named_tl}
+% Space to store the detail of the named color.
+% \begin{macrocode}
+\tl_new:N \l_@@_named_tl
+% \end{macrocode}
+% \end{variable}
+%
+% \begin{macro}{\color_set:nn}
+% \begin{macro}{\@@_set:nnn}
+% \begin{macro}{\@@_set:nn}
+% \begin{macro}{\@@_set:nnw}
+% \begin{macro}{\color_set:nnn, \@@_set_aux:nnn}
+% \begin{macro}{\@@_set_colon:nnw}
+% \begin{macro}{\@@_set_loop:nw}
+% \begin{macro}{\color_set_eq:nn}
+% Defining named colors means working through the model list and saving
+% both the \enquote{main} color and any equivalents in other models. Even
+% if there is only one model, we store a |prop| as well as a |tl|, as there
+% could be grouping weirdness, etc. When setting using an expression,
+% we need to avoid any fixed model issues, which is done without a group as
+% in \pkg{l3keys}.
+% \begin{macrocode}
+\cs_new_protected:Npn \color_set:nn #1#2
+ {
+ \exp_args:NV \@@_set:nnn
+ \l_color_fixed_model_tl {#1} {#2}
+ }
+\cs_new_protected:Npn \@@_set:nnn #1#2#3
+ {
+ \tl_clear:N \l_color_fixed_model_tl
+ \@@_set:nn {#2} {#3}
+ \tl_set:Nn \l_color_fixed_model_tl {#1}
+ }
+\cs_new_protected:Npn \@@_set:nn #1#2
+ {
+ \str_if_eq:nnF {#1} { . }
+ {
+ \@@_parse:nN {#2} \l_@@_named_tl
+ \tl_clear_new:c { l_@@_named_ #1 _tl }
+ \tl_set:ce { l_@@_named_ #1 _tl }
+ { \@@_model:N \l_@@_named_tl }
+ \prop_clear_new:c { l_@@_named_ #1 _prop }
+ \prop_put:cve { l_@@_named_ #1 _prop } { l_@@_named_ #1 _tl }
+ { \@@_values:N \l_@@_named_tl }
+ \@@_set:nnw {#1} {#2} #2 ! \s_@@_stop
+ }
+ }
+% \end{macrocode}
+% When setting an expression-based color, there could be multiple model
+% data available for one or more of the input colors. Where that is true for
+% the \emph{first} named color in an expression, we re-parse the expression
+% when they are also parameter-based: only |cmyk|, |gray| and |rgb| make
+% any sense here. There is a bit of a performance hit but this should be
+% rare and taking place during set-up.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_set:nnw #1#2#3 ! #4 \s_@@_stop
+ {
+ \clist_map_inline:nn { cmyk , gray , rgb }
+ {
+ \prop_get:cnNT { l_@@_named_ #3 _prop } {##1} \l_@@_internal_tl
+ {
+ \prop_if_in:cnF { l_@@_named_ #1 _prop } {##1}
+ {
+ \group_begin:
+ \bool_set_true:N \l_@@_ignore_error_bool
+ \tl_set:cn { l_@@_named_ #3 _tl } {##1}
+ \@@_parse:nN {#2} \l_@@_internal_tl
+ \exp_args:NNNV \group_end:
+ \tl_set:Nn \l_@@_internal_tl \l_@@_internal_tl
+ \prop_put:cee { l_@@_named_ #1 _prop }
+ { \@@_model:N \l_@@_internal_tl }
+ { \@@_values:N \l_@@_internal_tl }
+ }
+ }
+ }
+ }
+\cs_new_protected:Npn \color_set:nnn #1#2#3
+ {
+ \str_if_eq:nnF {#1} { . }
+ {
+ \tl_clear_new:c { l_@@_named_ #1 _tl }
+ \prop_clear_new:c { l_@@_named_ #1 _prop }
+ \exp_args:Ne \@@_set_aux:nnn { \tl_to_str:n {#2} }
+ {#1} {#3}
+ }
+ }
+\cs_new_protected:Npe \@@_set_aux:nnn #1#2#3
+ {
+ \exp_not:N \@@_set_colon:nnw {#2} {#3}
+ #1 \c_colon_str \c_colon_str \exp_not:N \s_@@_stop
+ }
+\use:e
+ {
+ \cs_new_protected:Npn \exp_not:N \@@_set_colon:nnw
+ #1#2 #3 \c_colon_str #4 \c_colon_str
+ #5 \exp_not:N \s_@@_stop
+ }
+ {
+ \tl_if_blank:nTF {#4}
+ { \@@_set_loop:nw {#1} #3 }
+ { \@@_set_loop:nw {#1} #4 }
+ / / \s_@@_mark #2 / / \s_@@_stop
+ }
+\cs_new_protected:Npn \@@_set_loop:nw
+ #1#2 / #3 \s_@@_mark #4 / #5 \s_@@_stop
+ {
+ \tl_if_blank:nF {#2}
+ {
+ \@@_select:nnN {#2} {#4} \l_@@_named_tl
+ \tl_set:Ne \l_@@_internal_tl { \@@_model:N \l_@@_named_tl }
+ \tl_if_empty:cT { l_@@_named_ #1 _tl }
+ { \tl_set_eq:cN { l_@@_named_ #1 _tl } \l_@@_internal_tl }
+ \prop_put:cVe { l_@@_named_ #1 _prop } \l_@@_internal_tl
+ { \@@_values:N \l_@@_named_tl }
+ \@@_set_loop:nw {#1} #3 \s_@@_mark #5 \s_@@_stop
+ }
+ }
+\cs_new_protected:Npn \color_set_eq:nn #1#2
+ {
+ \color_if_exist:nTF {#2}
+ {
+ \tl_clear_new:c { l_@@_named_ #1 _tl }
+ \prop_clear_new:c { l_@@_named_ #1 _prop }
+ \str_if_eq:nnTF {#2} { . }
+ {
+ \tl_set:ce { l_@@_named_ #1 _tl }
+ { \@@_model:N \l_@@_current_tl }
+ \prop_put:cve { l_@@_named_ #1 _prop } { l_@@_named_ #1 _tl }
+ { \@@_values:N \l_@@_current_tl }
+ }
+ {
+ \tl_set_eq:cc { l_@@_named_ #1 _tl } { l_@@_named_ #2 _tl }
+ \prop_set_eq:cc { l_@@_named_ #1 _prop } { l_@@_named_ #2 _prop }
+ }
+ }
+ {
+ \msg_error:nnn { color } { unknown-color } {#2}
+ }
+ }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% A small set of colors are always defined.
+% \begin{macrocode}
+\color_set:nnn { black } { gray } { 0 }
+\color_set:nnn { white } { gray } { 1 }
+\color_set:nnn { cyan } { cmyk } { 1 , 0 , 0 , 0 }
+\color_set:nnn { magenta } { cmyk } { 0 , 1 , 0 , 0 }
+\color_set:nnn { yellow } { cmyk } { 0 , 0 , 1 , 0 }
+\color_set:nnn { red } { rgb } { 1 , 0 , 0 }
+\color_set:nnn { green } { rgb } { 0 , 1 , 0 }
+\color_set:nnn { blue } { rgb } { 0 , 0 , 1 }
+% \end{macrocode}
+%
+% \begin{variable}{\l_@@_named_._prop, \l_@@_named_._tl}
+% A special named color: this is always defined though not fixed in
+% definition.
+% \begin{macrocode}
+\prop_new:c { l_@@_named_._prop }
+\tl_new:c { l_@@_named_._tl }
+\tl_set:ce { l_@@_named_._tl } { \@@_model:N \l_@@_current_tl }
+% \end{macrocode}
+% \end{variable}
+%
+% \subsection{Exporting colors}
+%
+% \begin{macro}{\color_export:nnN}
+% \begin{macro}{\color_export:nnnN}
+% \begin{macro}{\@@_export:nN}
+% \begin{macro}{\@@_export:nnnN}
+% \begin{macrocode}
+\cs_new_protected:Npn \color_export:nnN #1#2#3
+ {
+ \group_begin:
+ \tl_if_exist:cT { c_@@_export_ #2 _tl }
+ { \tl_set_eq:Nc \l_color_fixed_model_tl { c_@@_export_ #2 _tl } }
+ \@@_parse:nN {#1} #3
+ \@@_export:nN {#2} #3
+ \exp_args:NNNV \group_end:
+ \tl_set:Nn #3 #3
+ }
+\cs_new_protected:Npn \color_export:nnnN #1#2#3#4
+ {
+ \@@_select_main:Nw #4
+ #1 / / \s_@@_mark #2 / / \s_@@_stop
+ \@@_export:nN {#3} #4
+ }
+\cs_new_protected:Npn \@@_export:nN #1#2
+ { \exp_after:wN \@@_export:nnnN #2 {#1} #2 }
+\cs_new:Npn \@@_export:nnnN #1#2#3#4
+ {
+ \cs_if_exist_use:cF { @@_export_format_ #3 :nnN }
+ {
+ \msg_error:nnn { color } { unknown-export-format } {#3}
+ \use_none:nnn
+ }
+ {#1} {#2} #4
+ }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}{\@@_export_format_backend:nnN}
+% Simple.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_export_format_backend:nnN #1#2#3
+ { \tl_set:Nn #3 { {#1} {#2} } }
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\@@_export:nnnNN}
+% A generic auxiliary for cases where only one model is appropriate.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_export:nnnNN #1#2#3#4#5
+ {
+ \str_if_eq:nnTF {#2} {#1}
+ { #5 #4 #3 \s_@@_stop }
+ {
+ \@@_convert:nnnN {#2} {#1} {#3} #4
+ \exp_after:wN #5 \exp_after:wN #4
+ #4 \s_@@_stop
+ }
+ }
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{variable}
+% {
+% \c_@@_export_comma-sep-cmyk_tl ,
+% \c_@@_export_comma-sep-rgb_tl ,
+% \c_@@_export_HTML_tl ,
+% \c_@@_export_space-sep-cmyk_tl ,
+% \c_@@_export_space-sep-rgb_tl
+% }
+% \begin{macrocode}
+\tl_const:cn { c_@@_export_comma-sep-cmyk_tl } { cmyk }
+\tl_const:cn { c_@@_export_comma-sep-rgb_tl } { rgb }
+\tl_const:Nn \c_@@_export_HTML_tl { rgb }
+\tl_const:cn { c_@@_export_space-sep-cmyk_tl } { cmyk }
+\tl_const:cn { c_@@_export_space-sep-rgb_tl } { rgb }
+% \end{macrocode}
+% \end{variable}
+%
+% \begin{macro}
+% {
+% \@@_export_format_comma-sep-cmyk:nnN ,
+% \@@_export_format_comma-sep-rgb:nnN ,
+% \@@_export_format_space-sep-cmyk:nnN ,
+% \@@_export_format_space-sep-rgb:nnN
+% }
+% \begin{macrocode}
+\group_begin:
+ \cs_set_protected:Npn \@@_tmp:w #1#2
+ {
+ \cs_new_protected:cpe { @@_export_format_ #1 :nnN } ##1##2##3
+ {
+ \exp_not:N \@@_export:nnnNN {#2} {##1} {##2} ##3
+ \exp_not:c { @@_export_ #1 :Nw }
+ }
+ }
+ \@@_tmp:w { comma-sep-cmyk } { cmyk }
+ \@@_tmp:w { comma-sep-rgb } { rgb }
+ \@@_tmp:w { HTML } { rgb }
+ \@@_tmp:w { space-sep-cmyk } { cmyk }
+ \@@_tmp:w { space-sep-rgb } { rgb }
+
+\group_end:
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\@@_export_space-sep-cmyk:Nw, \@@_export_comma-sep-cmyk:Nw}
+% \begin{macrocode}
+\cs_new_protected:cpn { @@_export_comma-sep-cmyk:Nw }
+ #1#2 ~ #3 ~ #4 ~ #5 \s_@@_stop
+ { \tl_set:Nn #1 { #2 , #3 , #4 , #5 } }
+\cs_new_protected:cpn { @@_export_space-sep-cmyk:Nw } #1#2 \s_@@_stop
+ { \tl_set:Nn #1 {#2} }
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}
+% {
+% \@@_export_comma-sep-rgb:Nw ,
+% \@@_export_HTML:Nw ,
+% \@@_export_space-sep-rgb:Nw
+% }
+% \begin{macro}[EXP]{\@@_export_HTML:n}
+% \textsc{html} values must be given in |rgb|: we force conversion if
+% required, then do some simple maths.
+% \begin{macrocode}
+\cs_new_protected:cpn { @@_export_comma-sep-rgb:Nw } #1#2 ~ #3 ~ #4 \s_@@_stop
+ { \tl_set:Ne #1 { #2 , #3 , #4 } }
+\cs_new_protected:Npn \@@_export_HTML:Nw #1#2 ~ #3 ~ #4 \s_@@_stop
+ {
+ \tl_set:Ne #1
+ {
+ \@@_export_HTML:n {#2}
+ \@@_export_HTML:n {#3}
+ \@@_export_HTML:n {#4}
+ }
+ }
+\cs_new:Npn \@@_export_HTML:n #1
+ {
+ \fp_compare:nNnTF {#1} = { 0 }
+ { 00 }
+ {
+ \fp_compare:nNnT { #1 * 255 } < { 16 } { 0 }
+ \int_to_Hex:n { \fp_to_int:n { #1 * 255 } }
+ }
+ }
+\cs_new_protected:cpn { @@_export_space-sep-rgb:Nw } #1#2 \s_@@_stop
+ { \tl_set:Nn #1 {#2} }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+%
+% \subsection{Additional color models}
+%
+% \begin{variable}{\l_@@_internal_prop}
+% \begin{macrocode}
+\prop_new:N \l_@@_internal_prop
+% \end{macrocode}
+% \end{variable}
+%
+% \begin{variable}{\g_@@_model_int}
+% A tracker for the total number of new models.
+% \begin{macrocode}
+\int_new:N \g_@@_model_int
+% \end{macrocode}
+% \end{variable}
+%
+% \begin{variable}
+% {\c_@@_fallback_cmyk_tl, \c_@@_fallback_gray_tl, \c_@@_fallback_rgb_tl}
+% For every colorspace, we define one of the base colorspaces as a fallback.
+% The base colorspaces themselves are their own fallback.
+% \begin{macrocode}
+\tl_const:Nn \c_@@_fallback_cmyk_tl { cmyk }
+\tl_const:Nn \c_@@_fallback_gray_tl { gray }
+\tl_const:Nn \c_@@_fallback_rgb_tl { rgb }
+% \end{macrocode}
+% \end{variable}
+%
+% \begin{variable}{\g_@@_colorants_prop}
+% Mapping from names to colorants.
+% \begin{macrocode}
+\prop_new:N \g_@@_colorants_prop
+\prop_gput:Nnn \g_@@_colorants_prop { black } { Black }
+\prop_gput:Nnn \g_@@_colorants_prop { blue } { Blue }
+\prop_gput:Nnn \g_@@_colorants_prop { cyan } { Cyan }
+\prop_gput:Nnn \g_@@_colorants_prop { green } { Green }
+\prop_gput:Nnn \g_@@_colorants_prop { magenta } { Magenta }
+\prop_gput:Nnn \g_@@_colorants_prop { none } { None }
+\prop_gput:Nnn \g_@@_colorants_prop { red } { Red }
+\prop_gput:Nnn \g_@@_colorants_prop { yellow } { Yellow }
+% \end{macrocode}
+% \end{variable}
+%
+% \begin{variable}
+% {
+% \c_@@_model_whitepoint_CIELAB_a_tl ,
+% \c_@@_model_whitepoint_CIELAB_b_tl ,
+% \c_@@_model_whitepoint_CIELAB_e_tl ,
+% \c_@@_model_whitepoint_CIELAB_d50_tl ,
+% \c_@@_model_whitepoint_CIELAB_d55_tl ,
+% \c_@@_model_whitepoint_CIELAB_d65_tl ,
+% \c_@@_model_whitepoint_CIELAB_d75_tl
+% }
+% Whitepoint data for the CIELAB profiles.
+% \begin{macrocode}
+\tl_const:Nn \c_@@_model_whitepoint_CIELAB_a_tl { 1.0985 ~ 1 ~ 0.3558 }
+\tl_const:Nn \c_@@_model_whitepoint_CIELAB_b_tl { 0.9807 ~ 1 ~ 1.1822 }
+\tl_const:Nn \c_@@_model_whitepoint_CIELAB_e_tl { 1 ~ 1 ~ 1 }
+\tl_const:cn { c_@@_model_whitepoint_CIELAB_d50_tl } { 0.9642 ~ 1 ~ 0.8251 }
+\tl_const:cn { c_@@_model_whitepoint_CIELAB_d55_tl } { 0.9568 ~ 1 ~ 0.9214 }
+\tl_const:cn { c_@@_model_whitepoint_CIELAB_d65_tl } { 0.9504 ~ 1 ~ 1.0888 }
+\tl_const:cn { c_@@_model_whitepoint_CIELAB_d75_tl } { 0.9497 ~ 1 ~ 1.2261 }
+% \end{macrocode}
+% \end{variable}
+%
+% \begin{variable}{\c_@@_model_range_CIELAB_tl}
+% The range for CIELAB color spaces.
+% \begin{macrocode}
+\tl_const:Nn \c_@@_model_range_CIELAB_tl { 0 ~ 100 ~ -128 ~ 127 ~ -128 ~ 127 }
+% \end{macrocode}
+% \end{variable}
+%
+% \begin{variable}{\g_@@_alternative_model_prop}
+% For tracking the alternative model set up for separations, etc.
+% \begin{macrocode}
+\prop_new:N \g_@@_alternative_model_prop
+\clist_map_inline:nn { cyan , magenta , yellow , black }
+ { \prop_gput:Nnn \g_@@_alternative_model_prop {#1} { cmyk } }
+\clist_map_inline:nn { red , green , blue }
+ { \prop_gput:Nnn \g_@@_alternative_model_prop {#1} { rgb } }
+% \end{macrocode}
+% \end{variable}
+%
+% \begin{variable}{\g_@@_alternative_values_prop}
+% Same for the values: a bit more involved.
+% \begin{macrocode}
+\prop_new:N \g_@@_alternative_values_prop
+\prop_gput:Nnn \g_@@_alternative_values_prop { cyan } { 1 , 0 , 0 , 0 }
+\prop_gput:Nnn \g_@@_alternative_values_prop { magenta } { 0 , 1 , 0 , 0 }
+\prop_gput:Nnn \g_@@_alternative_values_prop { yellow } { 0 , 0 , 1 , 0 }
+\prop_gput:Nnn \g_@@_alternative_values_prop { black } { 0 , 0 , 0 , 1 }
+\prop_gput:Nnn \g_@@_alternative_values_prop { red } { 1 , 0 , 0 }
+\prop_gput:Nnn \g_@@_alternative_values_prop { green } { 0 , 1 , 0 }
+\prop_gput:Nnn \g_@@_alternative_values_prop { blue } { 0 , 0 , 1 }
+% \end{macrocode}
+% \end{variable}
+%
+% \begin{macro}{\color_model_new:nnn, \@@_model_new:nnn}
+% Set up a new model: in general this has to be handled by a family-dependent
+% function. To avoid some \enquote{interesting} questions with casing, we
+% fold the case of the family name. The key--value list should always be
+% present, so we convert it up-front to a |prop|, then deal with the detail
+% on a per-family basis.
+% \begin{macrocode}
+\cs_new_protected:Npn \color_model_new:nnn #1#2#3
+ {
+ \exp_args:Nee \@@_model_new:nnn
+ { \tl_to_str:n {#1} }
+ { \str_casefold:n {#2} } {#3}
+ }
+\cs_new_protected:Npn \@@_model_new:nnn #1#2#3
+ {
+ \cs_if_exist:cTF { @@_parse_model_ #1 :w }
+ {
+ \msg_error:nnn { color } { model-already-defined } {#1}
+ }
+ {
+ \cs_if_exist:cTF { @@_model_ #2 :n }
+ {
+ \prop_set_from_keyval:Nn \l_@@_internal_prop {#3}
+ \use:c { @@_model_ #2 :n } {#1}
+ }
+ {
+ \msg_error:nnn { color } { unknown-model-type } {#2}
+ }
+ }
+ }
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\@@_model_init:nnn, \@@_model_init:nne}
+% A shared auxiliary to do the basics of setting up a new model: reserve a
+% number, create a white-equivalent, set up links to the backend.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_model_init:nnn #1#2#3
+ {
+ \int_gincr:N \g_@@_model_int
+ \clist_map_inline:nn { fill , stroke , select }
+ {
+ \cs_new_protected:cpe { @@_backend_ ##1 _ #1 :n } ####1
+ {
+ \exp_not:c { @@_backend_ ##1 _ #2 :nn }
+ { color \int_use:N \g_@@_model_int } {####1}
+ }
+ }
+ \cs_new_protected:cpe { @@_model_ #1 _white: }
+ {
+ \prop_put:Nnn \exp_not:N \l_@@_named_white_prop {#1}
+ { \exp_not:n {#3} }
+ \exp_not:N \int_compare:nNnF { \tex_currentgrouplevel:D } = 0
+ { \group_insert_after:N \exp_not:c { @@_model_ #1 _ white: } }
+ }
+ \use:c { @@_model_ #1 _white: }
+ }
+\cs_generate_variant:Nn \@@_model_init:nnn { nne }
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\@@_model_separation:n}
+% \begin{macro}{\@@_model_separation:nn}
+% \begin{macro}{\@@_model_separation:nnn}
+% \begin{macro}{\@@_model_separation:w}
+% \begin{macro}
+% {
+% \@@_model_separation_cmyk:nnnnnn ,
+% \@@_model_separation_gray:nnnnnn ,
+% \@@_model_separation_rgb:nnnnnn
+% }
+% \begin{macro}{\@@_model_convert:nnn}
+% \begin{macro}{\@@_model_separation_CIELAB:nnnnnn}
+% \begin{macro}{\@@_model_separation_CIELAB:nnnnnnn}
+% Separations must have a \enquote{real} name, which is pretty easy to find.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_model_separation:n #1
+ {
+ \prop_get:NnNTF \l_@@_internal_prop { name }
+ \l_@@_internal_tl
+ {
+ \exp_args:NV \@@_model_separation:nn
+ \l_@@_internal_tl {#1}
+ }
+ {
+ \msg_error:nnn { color }
+ { separation-requires-name } {#1}
+ }
+ }
+% \end{macrocode}
+% We have two keys to find at this stage: the alternative space model
+% and linked values.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_model_separation:nn #1#2
+ {
+ \prop_get:NnNTF \l_@@_internal_prop { alternative-model }
+ \l_@@_internal_tl
+ {
+ \exp_args:NV \@@_model_separation:nnn
+ \l_@@_internal_tl {#2} {#1}
+ }
+ {
+ \msg_error:nnn { color }
+ { separation-alternative-model } {#2}
+ }
+ }
+\cs_new_protected:Npn \@@_model_separation:nnn #1#2#3
+ {
+ \cs_if_exist:cTF { @@_model_separation_ #1 :nnnnnn }
+ {
+ \prop_get:NnNTF \l_@@_internal_prop { alternative-values }
+ \l_@@_internal_tl
+ {
+ \exp_after:wN \@@_model_separation:w \l_@@_internal_tl
+ , 0 , 0 , 0 , 0 \s_@@_stop {#2} {#3} {#1}
+ }
+ {
+ \msg_error:nnn { color }
+ { separation-alternative-values } {#2}
+ }
+ }
+ {
+ \msg_error:nnn { color }
+ { unknown-alternative-model } {#1}
+ }
+ }
+% \end{macrocode}
+% As each alternative space leads to a different requirement for conversion,
+% and as there are only a small number of choices, we manually split the data
+% and then set up. Notice that mixing tints is really just the same
+% as mixing \texttt{gray}. The \texttt{white} color is special, as it allows
+% tints to be adjusted without an additional color space. To make sure the
+% data is set for that at all group levels, we need to work on a per-level
+% basis. Within the output, only the set-up needs the \enquote{real} name
+% of the colorspace: we use a simple tracking number for general usage
+% as this is a clear namespace without issues of escaping chars.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_model_separation:w
+ #1 , #2 , #3 , #4 , #5 \s_@@_stop #6#7#8
+ {
+ \@@_model_init:nnn {#6} { separation } { 0 }
+ \cs_new_eq:cN { @@_parse_mix_ #6 :nw } \@@_parse_mix_gray:nw
+ \cs_new:cpn { @@_parse_model_ #6 :w } ##1 , ##2 \s_@@_stop
+ { {#6} { \@@_parse_number:n {##1} } }
+ \use:c { @@_model_separation_ #8 :nnnnnn }
+ {#6} {#7} {#1} {#2} {#3} {#4}
+ \prop_gput:Nnn \g_@@_alternative_model_prop {#6} {#8}
+ \prop_gput:Nne \g_@@_colorants_prop {#6}
+ { \str_convert_pdfname:n {#7} }
+ }
+\cs_new_protected:Npn \@@_model_separation_cmyk:nnnnnn #1#2#3#4#5#6
+ {
+ \tl_const:cn { c_@@_fallback_ #1 _tl } { cmyk }
+ \cs_new:cpn { @@_convert_ #1 _cmyk:w } ##1 \s_@@_stop
+ {
+ \fp_eval:n {##1 * #3} ~
+ \fp_eval:n {##1 * #4} ~
+ \fp_eval:n {##1 * #5} ~
+ \fp_eval:n {##1 * #6}
+ }
+ \cs_new:cpn { @@_convert_cmyk_ #1 :w } ##1 \s_@@_stop { 1 }
+ \prop_gput:Nnn \g_@@_alternative_values_prop {#1} { #3 , #4 , #5 , #6 }
+ \@@_backend_separation_init:nnnnn {#2} { /DeviceCMYK } { }
+ { 0 ~ 0 ~ 0 ~ 0 } { #3 ~ #4 ~ #5 ~ #6 }
+ }
+\cs_new_protected:Npn \@@_model_separation_rgb:nnnnnn #1#2#3#4#5#6
+ {
+ \tl_const:cn { c_@@_fallback_ #1 _tl } { rgb }
+ \cs_new:cpn { @@_convert_ #1 _rgb:w } ##1 \s_@@_stop
+ {
+ \fp_eval:n {##1 * #3} ~
+ \fp_eval:n {##1 * #4} ~
+ \fp_eval:n {##1 * #5}
+ }
+ \cs_new:cpn { @@_convert_rgb_ #1 :w } ##1 \s_@@_stop { 1 }
+ \prop_gput:Nnn \g_@@_alternative_values_prop {#1} { #3 , #4 , #5 }
+ \@@_backend_separation_init:nnnnn {#2} { /DeviceRGB } { }
+ { 0 ~ 0 ~ 0 } { #3 ~ #4 ~ #5 }
+ }
+\cs_new_protected:Npn \@@_model_separation_gray:nnnnnn #1#2#3#4#5#6
+ {
+ \tl_const:cn { c_@@_fallback_ #1 _tl } { gray }
+ \cs_new:cpn { @@_convert_ #1 _gray:w } ##1 \s_@@_stop
+ { \fp_eval:n {##1 * #3} }
+ \cs_new:cpn { @@_convert_gray_ #1 :w } ##1 \s_@@_stop { 1 }
+ \prop_gput:Nnn \g_@@_alternative_values_prop {#1} {#3}
+ \@@_backend_separation_init:nnnnn {#2} { /DeviceGray } { } { 0 } {#3}
+ }
+% \end{macrocode}
+% Generic model conversion \emph{via} an alternative intermediate.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_model_convert:nnn #1#2#3
+ {
+ \cs_new:cpe { @@_convert_ #1 _ #3 :w } ##1 \s_@@_stop
+ {
+ \exp_not:N \exp_args:NNe \exp_not:N \use:nn
+ \exp_not:c { @@_convert_ #2 _ #3 :w }
+ { \exp_not:c { @@_convert_ #1 _ #2 :w } ##1 \s_@@_stop }
+ \c_space_tl \exp_not:N \s_@@_stop
+ }
+ }
+% \end{macrocode}
+% Setting up for CIELAB needs a bit more work: there is the illuminant and
+% the need for an appropriate object.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_model_separation_CIELAB:nnnnnn #1#2#3#4#5#6
+ {
+ \prop_get:NnNF \l_@@_internal_prop { illuminant }
+ \l_@@_internal_tl
+ {
+ \msg_error:nnn { color }
+ { CIELAB-requires-illuminant } {#1}
+ \tl_set:Nn \l_@@_internal_tl { d50 }
+ }
+ \exp_args:NV \@@_model_separation_CIELAB:nnnnnnn
+ \l_@@_internal_tl {#1} {#2} {#3} {#4} {#5} {#6}
+ }
+% \end{macrocode}
+% If a CIELAB space is being set up, we need the illuminant, then create
+% the appropriate set up. At present, this doesn't include \texttt{BlackPoint}
+% or \texttt{Range} data, but that may be added later. As CIELAB colors
+% cannot be converted to anything else, we fallback to producing black in the
+% gray colorspace: the user should set up a second model for colors set up this way.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_model_separation_CIELAB:nnnnnnn #1#2#3#4#5#6#7
+ {
+ \tl_if_exist:cTF { c_@@_model_whitepoint_CIELAB_ #1 _tl }
+ {
+ \@@_backend_separation_init_CIELAB:nnn {#1} {#3} { #4 ~ #5 ~ #6 }
+ \tl_const:cn { c_@@_fallback_ #2 _tl } { gray }
+ \cs_new:cpn { @@_convert_ #2 _gray:w } ##1 \s_@@_stop
+ { 0 }
+ \cs_new:cpn { @@_convert_gray_ #2 :w } ##1 \s_@@_stop
+ { 1 }
+ }
+ {
+ \msg_error:nnn { color }
+ { unknown-CIELAB-illuminant } {#1}
+ }
+ }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}{\@@_model_devicen:n}
+% \begin{macro}{\@@_model_devicen:nn}
+% \begin{macro}{\@@_model_devicen:nnn}
+% \begin{macro}{\@@_model_devicen:nnnn}
+% \begin{macro}
+% {
+% \@@_model_devicen_parse_1:nn ,
+% \@@_model_devicen_parse_2:nn ,
+% \@@_model_devicen_parse_3:nn ,
+% \@@_model_devicen_parse_4:nn ,
+% \@@_model_devicen_parse_generic:nn
+% }
+% \begin{macro}[EXP]{\@@_model_devicen_parse:nw}
+% \begin{macro}[EXP]{\@@_model_devicen_mix:nw}
+% \begin{macro}{\@@_model_devicen_init:nnn}
+% \begin{macro}{\@@_model_devicen_init:nnnn}
+% \begin{macro}{\@@_model_devicen_tranform:w}
+% \begin{macro}
+% {
+% \@@_model_devicen_tranform_1:nnnnn ,
+% \@@_model_devicen_tranform_3:nnnnn ,
+% \@@_model_devicen_tranform_4:nnnnn ,
+% }
+% \begin{macro}{\@@_model_devicen_tranform:nnn}
+% \begin{macro}[EXP]{\@@_model_devicen_colorant:n}
+% \begin{macro}{\@@_model_devicen_convert:nnn}
+% \begin{macro}
+% {
+% \@@_model_devicen_convert_cmyk:n ,
+% \@@_model_devicen_convert_gray:n ,
+% \@@_model_devicen_convert_rgb:n
+% }
+% \begin{macro}{\@@_model_devicen_convert:nnnn}
+% \begin{macro}[EXP]{\@@_model_devicen_convert:n, \@@_model_devicen_convert_aux:n}
+% \begin{macro}[EXP]{\@@_model_devicen_convert:w}
+% \begin{macro}[EXP]{\@@_convert_devicen_cmyk:nnnnw}
+% \begin{macro}[EXP]{\@@_convert_devicen_cmyk:nnnnnnnnn}
+% \begin{macro}[EXP]{\@@_convert_devicen_cmyk_aux:nnnnw}
+% \begin{macro}[EXP]{\@@_convert_devicen_gray:nw}
+% \begin{macro}[EXP]{\@@_convert_devicen_gray:nnn}
+% \begin{macro}[EXP]{\@@_convert_devicen_gray_aux:nw}
+% \begin{macro}[EXP]{\@@_convert_devicen_rgb:nnnw}
+% \begin{macro}[EXP]{\@@_convert_devicen_rgb:nnnnnnn}
+% \begin{macro}[EXP]{\@@_convert_devicen_rgb_aux:nnnw}
+% We require a list of component names here: one might call them colorants,
+% but it's convenient to use \TeX{} names instead so we slightly adjust the
+% terminology.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_model_devicen:n #1
+ {
+ \prop_get:NnNTF \l_@@_internal_prop { names }
+ \l_@@_internal_tl
+ {
+ \exp_args:NV \@@_model_devicen:nn
+ \l_@@_internal_tl {#1}
+ }
+ {
+ \msg_error:nnn { color }
+ { DeviceN-requires-names } {#1}
+ }
+ }
+% \end{macrocode}
+% All valid models will have an alternative listed, either hard-coded for
+% the core device ones, or dynamically added for Separations, etc.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_model_devicen:nn #1#2
+ {
+ \tl_clear:N \l_@@_model_tl
+ \clist_map_inline:nn {#1}
+ {
+ \prop_get:NnNTF \g_@@_alternative_model_prop {##1}
+ \l_@@_internal_tl
+ {
+ \tl_if_empty:NTF \l_@@_model_tl
+ { \tl_set_eq:NN \l_@@_model_tl \l_@@_internal_tl }
+ {
+ \str_if_eq:VVF \l_@@_model_tl \l_@@_internal_tl
+ {
+ \msg_error:nnn { color }
+ { DeviceN-inconsistent-alternative }
+ {#2}
+ \clist_map_break:n { \use_none:nnnn }
+ }
+ }
+ }
+ {
+ \str_if_eq:nnF {##1} { none }
+ {
+ \msg_error:nnn { color }
+ { DeviceN-no-alternative }
+ {#2}
+ }
+ }
+ }
+ \tl_if_empty:NTF \l_@@_model_tl
+ {
+ \msg_error:nnn { color }
+ { DeviceN-no-alternative } {#2}
+ }
+ { \exp_args:NV \@@_model_devicen:nnn \l_@@_model_tl {#1} {#2} }
+ }
+% \end{macrocode}
+% We now complete the data we require by first finding out how many
+% colorants there are, then moving on to begin constructing the function
+% required to map to the alternative color space.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_model_devicen:nnn #1#2#3
+ {
+ \exp_args:Ne \@@_model_devicen:nnnn
+ { \clist_count:n {#2} } {#1} {#2} {#3}
+ }
+% \end{macrocode}
+% At this stage, we have checked everything is in place, so we can set up
+% the \TeX{} and backend data structures. As for separations, it's not really
+% possible in general to have a fallback, so we simply provide
+% \enquote{black} for each element.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_model_devicen:nnnn #1#2#3#4
+ {
+ \@@_model_init:nne {#4} { devicen }
+ {
+ 0 \prg_replicate:nn { #1 - 1 } { ~ 0 }
+ }
+ \cs_if_exist_use:cF { @@_model_devicen_parse_ #1 :nn }
+ { \@@_model_devicen_parse_generic:nn }
+ {#4} {#1}
+ \@@_model_devicen_init:nnn {#1} {#2} {#3}
+ \@@_model_devicen_convert:nnne {#4} {#2} {#3}
+ {
+ 1 \prg_replicate:nn { #1 - 1 } { ~ 1 }
+ }
+ }
+% \end{macrocode}
+% For short lists of DeviceN colors, we can use hand-tuned parsing. This
+% lines up with other models, where we allow for up to four components. For
+% larger spaces, rather than limit artificially, we use a somewhat slow
+% approach based on open-ended commas-lists.
+% \begin{macrocode}
+\cs_new_protected:cpn { @@_model_devicen_parse_1:nn } #1#2
+ {
+ \cs_new:cpn { @@_parse_model_ #1 :w } ##1 , ##2 \s_@@_stop
+ { {#1} { \@@_parse_number:n {##1} } }
+ \cs_new_eq:cN { @@_parse_mix_ #1 :nw } \@@_parse_mix_gray:nw
+ }
+\cs_new_protected:cpn { @@_model_devicen_parse_2:nn } #1#2
+ {
+ \cs_new:cpn { @@_parse_model_ #1 :w } ##1 , ##2 , ##3 \s_@@_stop
+ { {#1} { \@@_parse_number:n {##1} ~ \@@_parse_number:n {##2} } }
+ \cs_new:cpn { @@_parse_mix_ #1 :nw }
+ ##1##2 ~ ##3 \s_@@_mark ##4 ~ ##5 \s_@@_stop
+ {
+ \fp_eval:n { ##2 * ##1 + ##4 * ( 1 - ##1 ) } \c_space_tl
+ \fp_eval:n { ##3 * ##1 + ##5 * ( 1 - ##1 ) }
+ }
+ }
+\cs_new_protected:cpn { @@_model_devicen_parse_3:nn } #1#2
+ {
+ \cs_new:cpn { @@_parse_model_ #1 :w } ##1 , ##2 , ##3 , ##4 \s_@@_stop
+ {
+ {#1}
+ {
+ \@@_parse_number:n {##1} ~
+ \@@_parse_number:n {##2} ~
+ \@@_parse_number:n {##3}
+ }
+ }
+ \cs_new_eq:cN { @@_parse_mix_ #1 :nw } \@@_parse_mix_rgb:nw
+ }
+\cs_new_protected:cpn { @@_model_devicen_parse_4:nn } #1#2
+ {
+ \cs_new:cpn { @@_parse_model_ #1 :w }
+ ##1 , ##2 , ##3 , ##4 , ##5 \s_@@_stop
+ {
+ {#1}
+ {
+ \@@_parse_number:n {##1} ~
+ \@@_parse_number:n {##2} ~
+ \@@_parse_number:n {##3} ~
+ \@@_parse_number:n {##4}
+ }
+ }
+ \cs_new_eq:cN { @@_parse_mix_ #1 :nw } \@@_parse_mix_cmyk:nw
+ }
+\cs_new_protected:Npn \@@_model_devicen_parse_generic:nn #1#2
+ {
+ \cs_new:cpn { @@_parse_model_ #1 :w } ##1 , ##2 \s_@@_stop
+ {
+ {#1}
+ { \@@_model_devicen_parse:nw {#2} ##1 , ##2 , \q_nil , \s_@@_stop }
+ }
+ \cs_new:cpe { @@_parse_mix_ #1 :nw }
+ ##1 ##2 \s_@@_mark ##3 \s_@@_stop
+ {
+ \exp_not:N \@@_model_devicen_mix:nw {##1}
+ ##2 \c_space_tl \exp_not:N \q_nil \c_space_tl \exp_not:N \s_@@_mark
+ ##3 \c_space_tl \exp_not:N \q_nil \c_space_tl \exp_not:N \s_@@_stop
+ }
+ }
+\cs_new:Npn \@@_model_devicen_parse:nw #1#2 , #3 \s_@@_stop
+ {
+ \int_compare:nNnT {#1} > 0
+ {
+ \quark_if_nil:nTF {#2}
+ { \prg_replicate:nn {#1} { 0 ~ } }
+ {
+ \@@_parse_number:n {#2}
+ \int_compare:nNnT {#1} > 1 { ~ }
+ \exp_args:Nf \@@_model_devicen_parse:nw
+ { \int_eval:n { #1 - 1 } } #3 \s_@@_stop
+ }
+ }
+ }
+\cs_new:Npn \@@_model_devicen_mix:nw #1#2 ~ #3 \s_@@_mark #4 ~ #5 \s_@@_stop
+ {
+ \fp_eval:n { #2 * #1 + #4 * ( 1 - #1 ) }
+ \quark_if_nil:oF { \tl_head:w #3 \q_stop }
+ {
+ \c_space_tl
+ \@@_model_devicen_mix:nw {#1} #3 \s_@@_mark #5 \s_@@_stop
+ }
+ }
+% \end{macrocode}
+% To construct the tint transformation, we have to use PostScript. The
+% aim is to have the final tint for each device colorant as
+% \[
+% 1 - \prod_{n} (1 - X_{n} D_{X_{n}})
+% \]
+% where $X$ is a DeviceN colorant and $D$ is the amount of device colorant
+% that the DeviceN colorant maps to. At the start of the process, the
+% PostScript stack will contain the $X_{n}$ values, whilst we have the
+% $D$ values on a per-DeviceN colorant basis. The more convenient approach
+% for us is therefore to take each DeviceN colorant in turn and find the
+% value $1 - X_{n} D_{X_{n}}$, multiplying as we go, and finalise with the
+% subtraction. That contrasts to \pkg{colorspace}: it splits the process
+% up by process color, which works better when you have a fixed list
+% of colorants. (\pkg{colorspace} only supports up to $4$ DeviceN colors,
+% and only \texttt{cmyk} as the alternative space.) To set this up,
+% we first need to know the number of values in the target color space:
+% this is easily handled as there are a very small range of possibles.
+% Once we have that information, it's relatively easy to build the required
+% PostScript using some generic code.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_model_devicen_init:nnn #1#2#3
+ {
+ \exp_args:Ne \@@_model_devicen_init:nnnn
+ {
+ \str_case:nn {#2}
+ {
+ { cmyk } { 4 }
+ { gray } { 1 }
+ { rgb } { 3 }
+ }
+ }
+ {#1} {#2} {#3}
+ }
+% \end{macrocode}
+% As we always need to split the alternative values into parts, we use a
+% shared auxiliary and only use a minimal difference between code paths.
+% Construction of the tint transformation is as far as possible done using
+% loops, which means there are some inefficiencies for device colors in
+% the \texttt{DeviceN} space: we roll the stack one-at-a-time even if there
+% is a potential shortcut. However, that way there is nothing to special-case.
+% Once this is sorted, we can write the tint transform object, which will
+% remain as the last object until we sort out the final step: the colorant
+% list.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_model_devicen_init:nnnn #1#2#3#4
+ {
+ \tl_set:Ne \l_@@_internal_tl
+ { \prg_replicate:nn {#1} { 1.0 ~ } }
+ \int_zero:N \l_@@_internal_int
+ \clist_map_inline:nn {#4}
+ {
+ \int_incr:N \l_@@_internal_int
+ \prop_get:NnN \g_@@_alternative_values_prop {##1}
+ \l_@@_value_tl
+ \exp_after:wN \@@_model_devicen_transform:w
+ \l_@@_value_tl , 0 , 0 , 0 , \s_@@_stop {#1} {#2}
+ }
+ \tl_put_right:Ne \l_@@_internal_tl
+ {
+ \prg_replicate:nn {#1}
+ { neg ~ 1.0 ~ add ~ #1 ~ -1 ~ roll ~ }
+ \int_eval:n { #2 + #1 } ~ #1 ~ roll
+ \prg_replicate:nn {#2} { ~ pop } ~
+ #1 ~ 1 ~ roll
+ }
+ \use:e
+ {
+ \@@_backend_devicen_init:nnn
+ {
+ \clist_map_function:nN {#4}
+ \@@_model_devicen_colorant:n
+ }
+ {
+ \str_case:nn {#3}
+ {
+ { cmyk } { /DeviceCMYK }
+ { gray } { /DeviceGray }
+ { rgb } { /DeviceRGB }
+ }
+ }
+ { \exp_not:V \l_@@_internal_tl }
+ }
+ }
+\cs_new_protected:Npn \@@_model_devicen_transform:w
+ #1 , #2 , #3 , #4 , #5 \s_@@_stop #6#7
+ {
+ \use:c { @@_model_devicen_transform_ #6 :nnnnn }
+ {#1} {#2} {#3} {#4} {#7}
+ }
+\cs_new_protected:cpn { @@_model_devicen_transform_1:nnnnn } #1#2#3#4#5
+ { \@@_model_devicen_transform:nnn {#5} { 1 } {#1} }
+\cs_new_protected:cpn { @@_model_devicen_transform_3:nnnnn } #1#2#3#4#5
+ {
+ \clist_map_inline:nn { #1 , #2 , #3 }
+ { \@@_model_devicen_transform:nnn {#5} { 3 } {##1} }
+ }
+\cs_new_protected:cpn { @@_model_devicen_transform_4:nnnnn } #1#2#3#4#5
+ {
+ \clist_map_inline:nn { #1 , #2 , #3 , #4 }
+ { \@@_model_devicen_transform:nnn {#5} { 4 } {##1} }
+ }
+\cs_new_protected:Npn \@@_model_devicen_transform:nnn #1#2#3
+ {
+ \tl_put_right:Ne \l_@@_internal_tl
+ {
+ \fp_compare:nNnF {#3} = \c_zero_fp
+ {
+ \int_eval:n { #1 - \l_@@_internal_int + #2 } ~ index ~
+ -#3 ~ mul ~ 1.0 ~ add ~ mul ~
+ }
+ #2 ~ -1 ~ roll ~
+ }
+ }
+\cs_new:Npn \@@_model_devicen_colorant:n #1
+ {
+ / \prop_item:Nn \g_@@_colorants_prop {#1} ~
+ }
+% \end{macrocode}
+% Here we need to set up conversion from the DeviceN space to the alternative
+% at the \TeX{} level. This also means supplying methods for inter-converting
+% to other parameter-based spaces. Essentially the approach is exactly the same
+% as the PostScript, just expressed in \TeX{} terms.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_model_devicen_convert:nnnn #1#2#3
+ {
+ \use:c { @@_model_devicen_convert_ #2 :nnn } {#1} {#3}
+ }
+\cs_generate_variant:Nn \@@_model_devicen_convert:nnnn { nnne }
+\cs_new_protected:Npn \@@_model_devicen_convert_cmyk:nnn #1#2
+ {
+ \tl_const:cn { c_@@_fallback_ #1 _tl } { cmyk }
+ \@@_model_devicen_convert:nnnnn {#1} { cmyk } { 4 } {#2}
+ }
+\cs_new_protected:Npn \@@_model_devicen_convert_gray:nnn #1#2
+ {
+ \tl_const:cn { c_@@_fallback_ #1 _tl } { gray }
+ \@@_model_devicen_convert:nnnnn {#1} { gray } { 1 } {#2}
+ }
+\cs_new_protected:Npn \@@_model_devicen_convert_rgb:nnn #1#2
+ {
+ \tl_const:cn { c_@@_fallback_ #1 _tl } { rgb }
+ \@@_model_devicen_convert:nnnnn {#1} { rgb } { 3 } {#2}
+ }
+\cs_new_protected:Npn \@@_model_devicen_convert:nnnnn #1#2#3#4#5
+ {
+ \cs_new:cpn { @@_convert_ #2 _ #1 :w } ##1 \s_@@_stop {#5}
+ \cs_new:cpe { @@_convert_ #1 _ #2 :w } ##1 \s_@@_stop
+ {
+ \exp_not:c { @@_convert_devicen_ #2 : \prg_replicate:nn {#3} { n } w }
+ \prg_replicate:nn {#3} { { 1 } }
+ ##1 ~ \exp_not:N \s_@@_mark
+ \clist_map_function:nN {#4} \@@_model_devicen_convert:n
+ {}
+ \exp_not:N \s_@@_stop
+ }
+ }
+\cs_new:Npn \@@_model_devicen_convert:n #1
+ {
+ {
+ \exp_args:Ne \@@_model_devicen_convert_aux:n
+ { \prop_item:Nn \g_@@_alternative_values_prop {#1} }
+ }
+ }
+\cs_new:Npn \@@_model_devicen_convert_aux:n #1
+ { \@@_model_devicen_convert_aux:w #1 , , , , \s_@@_stop }
+\cs_new:Npn \@@_model_devicen_convert_aux:w #1 , #2 , #3 , #4 , #5 \s_@@_stop
+ {
+ {#1}
+ \tl_if_blank:nF {#2}
+ {
+ {#2}
+ \tl_if_blank:nF {#3}
+ {
+ {#3}
+ \tl_if_blank:nF {#4} { {#4} }
+ }
+ }
+ }
+\cs_new:Npn \@@_convert_devicen_cmyk:nnnnw
+ #1#2#3#4#5 ~ #6 \s_@@_mark #7#8 \s_@@_stop
+ {
+ \@@_convert_devicen_cmyk:nnnnnnnnn {#5} {#1} {#2} {#3} {#4} #7
+ #6 \s_@@_mark #8 \s_@@_stop
+ }
+\cs_new:Npn \@@_convert_devicen_cmyk:nnnnnnnnn #1#2#3#4#5#6#7#8#9
+ {
+ \use:e
+ {
+ \exp_not:N \@@_convert_devicen_cmyk_aux:nnnnw
+ { \fp_eval:n { #2 * (1 - (#1 * #6)) } }
+ { \fp_eval:n { #3 * (1 - (#1 * #7)) } }
+ { \fp_eval:n { #4 * (1 - (#1 * #8)) } }
+ { \fp_eval:n { #5 * (1 - (#1 * #9)) } }
+ }
+ }
+\cs_new:Npn \@@_convert_devicen_cmyk_aux:nnnnw
+ #1#2#3#4 #5 \s_@@_mark #6 \s_@@_stop
+ {
+ \tl_if_blank:nTF {#5}
+ {
+ \fp_eval:n { 1 - #1 } ~
+ \fp_eval:n { 1 - #2 } ~
+ \fp_eval:n { 1 - #3 } ~
+ \fp_eval:n { 1 - #4 }
+ }
+ {
+ \@@_convert_devicen_cmyk:nnnnw {#1} {#2} {#3} {#4}
+ #5 \s_@@_mark #6 \s_@@_stop
+ }
+ }
+\cs_new:Npn \@@_convert_devicen_gray:nw
+ #1#2 ~ #3 \s_@@_mark #4#5 \s_@@_stop
+ {
+ \@@_convert_devicen_gray:nnn {#2} {#1} #4
+ #3 \s_@@_mark #5 \s_@@_stop
+ }
+\cs_new:Npn \@@_convert_devicen_gray:nnn #1#2#3
+ {
+ \exp_arsgs:Ne \@@_convert_devicen_gray_aux:nw
+ { \fp_eval:n { #2 * (1 - (#1 * #3)) } }
+ }
+\cs_new:Npn \@@_convert_devicen_gray_aux:nw
+ #1 #2 \s_@@_mark #3 \s_@@_stop
+ {
+ \tl_if_blank:nTF {#2}
+ { \fp_eval:n { 1 - #1 } }
+ {
+ \@@_convert_devicen_gray:nw {#1}
+ #2 \s_@@_mark #3 \s_@@_stop
+ }
+ }
+\cs_new:Npn \@@_convert_devicen_rgb:nnnw
+ #1#2#3#4 ~ #5 \s_@@_mark #6#7 \s_@@_stop
+ {
+ \@@_convert_devicen_rgb:nnnnnnn {#4} {#1} {#2} {#3} #6
+ #5 \s_@@_mark #7 \s_@@_stop
+ }
+\cs_new:Npn \@@_convert_devicen_rgb:nnnnnnn #1#2#3#4#5#6#7
+ {
+ \use:e
+ {
+ \exp_not:N \@@_convert_devicen_rgb_aux:nnnw
+ { \fp_eval:n { #2 * (1 - (#1 * #5)) } }
+ { \fp_eval:n { #3 * (1 - (#1 * #6)) } }
+ { \fp_eval:n { #4 * (1 - (#1 * #7)) } }
+ }
+ }
+\cs_new:Npn \@@_convert_devicen_rgb_aux:nnnw
+ #1#2#3 #4 \s_@@_mark #5 \s_@@_stop
+ {
+ \tl_if_blank:nTF {#4}
+ {
+ \fp_eval:n { 1 - #1 } ~
+ \fp_eval:n { 1 - #2 } ~
+ \fp_eval:n { 1 - #3 }
+ }
+ {
+ \@@_convert_devicen_rgb:nnnw {#1} {#2} {#3}
+ #4 \s_@@_mark #5 \s_@@_stop
+ }
+ }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \begin{variable}{\c_@@_icc_colorspace_signatures_prop}
+% The signatures in the ICC file header indicating the underlying
+% colorspace. We map it to three values: The number of components,
+% the values corresponding to white, and the range.
+% \begin{macrocode}
+\prop_const_from_keyval:Nn \c_@@_icc_colorspace_signatures_prop
+ {
+% Gray
+ 47524159 = {1} {1} {0} {},
+% RGB
+ 52474220 = {3} {0~0~0} {1~1~1} {},
+% CMYK
+ 434D594B = {4} {0~0~0~1} {0~0~0~0} {},
+% Lab
+ 4C616220 = {3} {0~0~0} {100~0~0} {0~100~-128~127~-128~127}
+ }
+% \end{macrocode}
+% \end{variable}
+% \begin{macro}{\@@_model_iccbased:n}
+% \begin{macro}{\@@_model_iccbased:nn}
+% \begin{macro}{\@@_model_iccbased:nnn, \@@_model_iccbased_aux:nnn}
+% For an ICC profile, we need a file name and a number of components. The
+% file name is processed here so the backend can treat it as a string.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_model_iccbased:n #1
+ {
+ \prop_get:NnNTF \l_@@_internal_prop { file }
+ \l_@@_internal_tl
+ {
+ \exp_args:NV \@@_model_iccbased:nn
+ \l_@@_internal_tl {#1}
+ }
+ {
+ \msg_error:nnn { color }
+ { ICCBased-requires-file } {#1}
+ }
+ }
+\cs_new_protected:Npn \@@_model_iccbased:nn #1#2
+ {
+ \prop_get:NeNTF \c_@@_icc_colorspace_signatures_prop
+ { \file_hex_dump:nnn { #1 } { 17 } { 20 } } \l_@@_internal_tl
+ {
+ \exp_last_unbraced:NV \@@_model_iccbased_aux:nnnnnn
+ \l_@@_internal_tl { #2 } { #1 }
+ }
+ {
+ \msg_error:nnn { color }
+ { ICCBased-unsupported-colorspace } {#2}
+ }
+ }
+% \end{macrocode}
+% Here, we can use the same internals as for DeviceN approach as we know the
+% number of components. No conversion is possible, so there is no need
+% to worry about that at all.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_model_iccbased_aux:nnnnnn #1#2#3#4#5#6
+ {
+ \@@_model_init:nnn {#5} { iccbased } {#3}
+ \tl_const:cn { c_@@_fallback_ #5 _tl } { gray }
+ \cs_new:cpn { @@_convert_ #5 _gray:w } ##1 \s_@@_stop { 0 }
+ \cs_new:cpn { @@_convert_gray_ #5 :w } ##1 \s_@@_stop { #2 }
+ \use:c { @@_model_devicen_parse_ #1 :nn } {#5} {#1}
+ \exp_args:Ne \@@_backend_iccbased_init:nnn
+ { \file_full_name:n {#6} } {#1} {#4}
+ }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \subsection{Applying profiles}
+%
+% \begin{macro}{\color_profile_apply:nn, \@@_profile_apply:nn}
+% \begin{macro}
+% {
+% \@@_profile_apply_gray:n ,
+% \@@_profile_apply_rgb:n ,
+% \@@_profile_apply_cmyk:n
+% }
+% With a limited range of outcomes, this is largely about getting data to the
+% backend.
+% \begin{macrocode}
+\cs_new_protected:Npn \color_profile_apply:nn #1#2
+ {
+ \exp_args:Ne \@@_profile_apply:nn
+ { \file_full_name:n {#1} } {#2}
+ }
+\cs_new_protected:Npn \@@_profile_apply:nn #1#2
+ {
+ \cs_if_exist_use:cF { @@_profile_apply_ \tl_to_str:n {#2} :n }
+ {
+ \msg_error:nnn { color } { ICC-Device-unknown } {#2}
+ \use_none:n
+ }
+ {#1}
+ }
+\cs_new_protected:Npn \@@_profile_apply_gray:n #1
+ {
+ \int_gincr:N \g_@@_model_int
+ \@@_backend_iccbased_device:nnn {#1} { Gray } { 1 }
+ }
+\cs_new_protected:Npn \@@_profile_apply_rgb:n #1
+ {
+ \int_gincr:N \g_@@_model_int
+ \@@_backend_iccbased_device:nnn {#1} { RGB } { 3 }
+ }
+\cs_new_protected:Npn \@@_profile_apply_cmyk:n #1
+ {
+ \int_gincr:N \g_@@_model_int
+ \@@_backend_iccbased_device:nnn {#1} { CMYK } { 4 }
+ }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+%
+% \subsection{Diagnostics}
+%
+% \begin{macro}{\color_show:n, \color_log:n, \@@_show:Nn}
+% \begin{macro}[EXP]{\@@_show:n}
+% Extract the information about a color and format for the user: the approach
+% is similar to the keys module here.
+% \begin{macrocode}
+\cs_new_protected:Npn \color_show:n
+ { \@@_show:Nn \msg_show:nneeee }
+\cs_new_protected:Npn \color_log:n
+ { \@@_show:Nn \msg_log:nneeee }
+\cs_new_protected:Npn \@@_show:Nn #1#2
+ {
+ #1 { color } { show }
+ {#2}
+ {
+ \color_if_exist:nT {#2}
+ {
+ \exp_args:Nv \@@_show:n { l_@@_named_ #2 _tl }
+ \prop_map_function:cN
+ { l_@@_named_ #2 _prop }
+ \msg_show_item_unbraced:nn
+ }
+ }
+ { }
+ { }
+ }
+\cs_new:Npn \@@_show:n #1
+ {
+ \msg_show_item_unbraced:nn { model } {#1}
+ }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+%
+% \subsection{Messages}
+%
+% \begin{macrocode}
+\msg_new:nnnn { color } { CIELAB-requires-illuminant }
+ { CIELAB~color~space~'#1'~require~an~illuminant. }
+ {
+ LaTeX~has~been~asked~to~create~a~separation~color~space~using~
+ CIELAB~specifications,~but~no~\\ \\
+ \iow_indent:n { illuminant~=~<basis> }
+ \\ \\
+ key~was~given~with~the~correct~information.~LaTeX~will~use~illuminant~
+ 'd50'~for~recovery.
+ }
+\msg_new:nnnn { color } { conversion-not-available }
+ { No~model~conversion~available~from~'#1'~to~'#2'. }
+ {
+ LaTeX~has~been~asked~to~convert~a~color~from~model~'#1'~
+ to~model'#2',~but~there~is~no~method~available~to~do~that.
+ }
+\msg_new:nnnn { color } { DeviceN-inconsistent-alternative }
+ { DeviceN~color~spaces~require~a~single~alternative~space. }
+ {
+ LaTeX~has~been~asked~to~create~a~DeviceN~color~space~'#1',~
+ but~the~constituent~colors~do~not~have~a~common~alternative~
+ color.
+ }
+\msg_new:nnnn { color } { DeviceN-no-alternative }
+ { DeviceN~color~spaces~require~an~alternative~space. }
+ {
+ LaTeX~has~been~asked~to~create~a~DeviceN~color~space~'#1',~
+ but~the~constituent~colors~do~not~all~have~a~device-based~alternative.
+ }
+\msg_new:nnnn { color } { DeviceN-requires-names }
+ { DeviceN~color~space~'#1'~require~a~list~of~names. }
+ {
+ LaTeX~has~been~asked~to~create~a~DeviceN~color~space,~
+ but~no~\\ \\
+ \iow_indent:n { names~=~<names> }
+ \\ \\
+ key~was~given~with~the~correct~information.
+ }
+\msg_new:nnnn { color } { ICC-Device-unknown }
+ { Unknown~device~color~space~'#1'. }
+ {
+ LaTeX~has~been~asked~to~apply~an~ICC~profile~but~the~device~color~space~
+ '#1'~is~unknown.
+ }
+\msg_new:nnnn { color } { ICCBased-unsupported-colorspace }
+ { ICCBased~color~space~'#1'~uses~an~unsupported~data~color~space. }
+ {
+ LaTeX~has~been~asked~to~create~a~ICCBased~colorspace,~but~the~
+ used~data~colorspace~is~not~supported.~ICC~profiles~used~for~
+ defining~a~ICCBased~colorspace~should~use~a~Lab,~RGB,~or~
+ CMYK~data~colorspace.~LaTeX~will~ignore~this~request.
+ }
+\msg_new:nnnn { color } { ICCBased-requires-file }
+ { ICCBased~color~space~'#1'~require~an~file. }
+ {
+ LaTeX~has~been~asked~to~create~an~ICCBased~color~space,~but~no~\\ \\
+ \iow_indent:n { file~=~<name> }
+ \\ \\
+ key~was~given~with~the~correct~information.~LaTeX~will~ignore~this~
+ request.
+ }
+\msg_new:nnnn { color } { model-already-defined }
+ { Color~model~'#1'~already~defined. }
+ {
+ LaTeX~was~asked~to~define~a~new~color~model~called~'#1',~but~
+ this~color~model~already~exists.
+ }
+\msg_new:nnnn { color } { out-of-range }
+ { Input~value~#1~out~of~range~[#2,~#3]. }
+ {
+ LaTeX~was~expecting~a~value~in~the~range~[#2,~#3]~as~part~of~a~color,~
+ but~you~gave~#1.~LaTeX~will~assume~you~meant~the~limit~of~the~range~
+ and~continue.
+ }
+\msg_new:nnnn { color } { separation-alternative-model }
+ { Separation~color~space~'#1'~require~an~alternative~model. }
+ {
+ LaTeX~has~been~asked~to~create~a~separation~color~space,~
+ but~no~\\ \\
+ \iow_indent:n { alternative-model~=~<model> }
+ \\ \\
+ key~was~given~with~the~correct~information.
+ }
+\msg_new:nnnn { color } { separation-alternative-values }
+ { Separation~color~space~'#1'~require~values~for~the~alternative~space. }
+ {
+ LaTeX~has~been~asked~to~create~a~separation~color~space,~
+ but~no~\\ \\
+ \iow_indent:n { alternative-values~=~<model> }
+ \\ \\
+ key~was~given~with~the~correct~information.
+ }
+\msg_new:nnnn { color } { separation-requires-name }
+ { Separation~color~space~'#1'~require~a~formal~name. }
+ {
+ LaTeX~has~been~asked~to~create~a~separation~color~space,~
+ but~no~\\ \\
+ \iow_indent:n { name~=~<formal~name> }
+ \\ \\
+ key~was~given~with~the~correct~information.
+ }
+\msg_new:nnn { color } { unhandled-model }
+ {
+ Unhandled~color~model~in~LaTeX2e~value~"#1":
+ \\ \\
+ falling~back~on~grayscale.
+ }
+\msg_new:nnnn { color } { unknown-color }
+ { Unknown~color~'#1'. }
+ {
+ LaTeX~has~been~asked~to~use~a~color~named~'#1',~
+ but~this~has~never~been~defined.
+ }
+\msg_new:nnnn { color } { unknown-alternative-model }
+ { Separation~color~space~'#1'~require~an~valid~alternative~space. }
+ {
+ LaTeX~has~been~asked~to~create~a~separation~color~space,~
+ but~the~model~given~as\\ \\
+ \iow_indent:n { alternative-model~=~<model> }
+ \\ \\
+ is~unknown.
+ }
+\msg_new:nnnn { color } { unknown-export-format }
+ { Unknown~export~format~'#1'. }
+ {
+ LaTeX~has~been~asked~to~export~a~color~in~format~'#1',~
+ but~this~has~never~been~defined.
+ }
+\msg_new:nnnn { color } { unknown-CIELAB-illuminant }
+ { Unknown~illuminant~model~'#1'. }
+ {
+ LaTeX~has~been~asked~to~use~create~a~color~space~using~CIELAB~
+ illuminant~'#1',~but~this~does~not~exist.
+ }
+\msg_new:nnnn { color } { unknown-model }
+ { Unknown~color~model~'#1'. }
+ {
+ LaTeX~has~been~asked~to~use~a~color~model~called~'#1',~
+ but~this~model~is~not~set~up.
+ }
+\msg_new:nnnn { color } { unknown-model-type }
+ { Unknown~color~model~type~'#1'. }
+ {
+ LaTeX~has~been~asked~to~create~a~new~color~model~called~'#1',~
+ but~this~type~of~model~was~never~set~up.
+ }
+\prop_gput:Nnn \g_msg_module_name_prop { color } { LaTeX }
+\prop_gput:Nnn \g_msg_module_type_prop { color } { }
+% \end{macrocode}
+%
+% \begin{macrocode}
+\msg_new:nnn { color } { show }
+ {
+ The~color~#1~
+ \tl_if_empty:nTF {#2}
+ { is~undefined. }
+ { has~the~properties: #2 }
+ }
+% \end{macrocode}
+%
+% \begin{macrocode}
+%</package>
+% \end{macrocode}
+%
+% \end{implementation}
+%
+% \PrintIndex