% \iffalse meta-comment % %% File: l3color-base.dtx % % Copyright (C) 2011,2012,2014,2016-2020 The LaTeX3 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 % % https://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,kernel]{l3doc} \begin{document} \DocInput{\jobname.dtx} \end{document} % % \fi % % \title{^^A % The \textsf{l3color-base} package\\ Color support^^A % } % % \author{^^A % The \LaTeX3 Project\thanks % {^^A % E-mail: % \href{mailto:latex-team@latex-project.org} % {latex-team@latex-project.org}^^A % }^^A % } % % \date{Released 2020-05-14} % % \maketitle % % \begin{documentation} % % This module provides support for color in \LaTeX3{}. At present, the % material here is mainly intended to support a small number of low-level % requirements in other \pkg{l3kernel} modules. % % \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. % \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} % % \end{documentation} % % \begin{implementation} % % \section{\pkg{l3color-base} Implementation} % % \begin{macrocode} %<*initex|package> % \end{macrocode} % % \begin{macrocode} %<@@=color> % \end{macrocode} % % \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} is space-separated as % this allows it to be used directly in specials in many common cases. % This internal representation is close to that used by the \texttt{dvips} % program. % \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: { %<*package> \@@_backend_pickup:N \l_@@_current_tl % \@@_select:V \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:V} % \begin{macro}{\@@_select:w} % \begin{macro} % {\@@_select_cmyk:w, \@@_select_gray:w, \@@_select_rgb:w, \@@_select_spot:w} % 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 experimental material. % \begin{macrocode} \cs_new_protected:Npn \@@_select:n #1 { \@@_select:w #1 \s_@@_stop } \cs_generate_variant:Nn \@@_select:n { V } \cs_new_protected:Npn \@@_select:w #1 ~ #2 \s_@@_stop { \use:c { @@_select_ #1 :w } #2 \s_@@_stop } \cs_new_protected:Npn \@@_select_cmyk:w #1 ~ #2 ~ #3 ~ #4 \s_@@_stop { \@@_backend_cmyk:nnnn {#1} {#2} {#3} {#4} } \cs_new_protected:Npn \@@_select_gray:w #1 \s_@@_stop { \@@_backend_gray:n {#1} } \cs_new_protected:Npn \@@_select_rgb:w #1 ~ #2 ~ #3 \s_@@_stop { \@@_backend_rgb:nnn {#1} {#2} {#3} } \cs_new_protected:Npn \@@_select_spot:w #1 ~ #2 \s_@@_stop { \@@_backend_spot:nn {#1} {#2} } % \end{macrocode} % \end{macro} % \end{macro} % \end{macro} % % \begin{variable}{\l_@@_current_tl} % As the setting data is used only % for specials, and those are always space-separated, it makes most sense to % hold the internal information in that form. % \begin{macrocode} \tl_new:N \l_@@_current_tl \tl_set:Nn \l_@@_current_tl { gray~0 } % \end{macrocode} % \end{variable} % % \begin{macrocode} % % \end{macrocode} % % \end{implementation} % % \PrintIndex