%D \module
%D   [       file=attr-col,
%D        version=2007.06.06,
%D          title=\CONTEXT\ Attribute Macros,
%D       subtitle=Color,
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright={PRAGMA ADE \& \CONTEXT\ Development Team}]
%C
%C This module is part of the \CONTEXT\ macro||package and is
%C therefore copyrighted by \PRAGMA. See mreadme.pdf for
%C details.

\writestatus{loading}{ConTeXt Attribute Macros / Color}

\registerctxluafile{attr-col}{1.001}

\unprotect

% todo: no need for 'color' argument, we can set that once at startup; currently
% a bit inconsistent

% 1=off  2=gray  3=spot  4=rgb  5=cmyk  6=cmy % only 1/2/4/5 are supported
%
% We could combine this in one attribute but this is not faster and also
% less flexible because sometimes we want to freeze the attribute bit.

% % color (layer on top)
%
% \def\dosetcolormodel#1% overloaded later
%   {\ctxcommand{setcolormodel('#1')}} % sets attribute
%
% \dosetcolormodel{all}
%
% \def\registerrgbcolor#1#2#3#4% not used
%   {\setevalue{(cs:#1)}{\attribute\colorattribute\ctxcommand{registercolor('#1','rgb' ,#2,#3,#4)}}}
%
% \def\registercmykcolor#1#2#3#4#5% not used
%   {\setevalue{(cs:#1)}{\attribute\colorattribute\ctxcommand{registercolor('#1','cmyk',#2,#3,#4,#5)}}}
%
% \def\registergraycolor#1#2% not used
%   {\setevalue{(cs:#1)}{\attribute\colorattribute\ctxcommand{registercolor('#1','gray',#2)}}}

% % transparency (layer on top)
%
% \def\registertransparency#1#2#3%
%   {\setevalue{(ts:#1)}{\attribute\transparencyattribute\ctxcommand{registertransparency(#2,#3)} }}
%
% \def\sometransparencyswitch#1%
%   {\csname(ts:#1)\endcsname}
%
% \def\sometransparencyswitch
%   {\ctxcommand{enabletransparency()}%
%    \gdef\sometransparencyswitch##1{\csname(ts:##1)\endcsname}%
%    \sometransparencyswitch}
%
% \registertransparency {one} {1} {.5}
% \registertransparency {two} {1} {.6}

% overprint

\def\registercolorintent#1#2%
  {\setevalue{(os:#1)}{\attribute\colorintentattribute\ctxcommand{registercolorintent('#2')} }}

\def\dotriggercolorintent
  {\ctxcommand{enablecolorintents()}%
   \gdef\dotriggercolorintent##1{\csname(os:##1)\endcsname}%
   \dotriggercolorintent}

\registercolorintent{knockout} {knockout}
\registercolorintent{overprint}{overprint}

\installattributestack\colorintentattribute

\setevalue{(os:#\v!none}{\attribute\colorintentattribute\attributeunsetvalue} % does this work out ok?

\protect \endinput

% test case
%
% {\green \hbox to \hsize{\leaders\hrule  \hfill a}\par}
% {\red   \hbox to \hsize{\leaders\hbox{x}\hfill a}\par}