%D \module
%D   [       file=colo-ext, % mostof thsi code used to be in colo-ini.tex
%D        version=1997.04.01,
%D          title=\CONTEXT\ Color Macros,
%D       subtitle=Extras,
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright={PRAGMA / Hans Hagen \& Ton Otten}]
%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 Color Macros / Extras}

\unprotect

%D \macros
%D   {negatecolorcomponent, negativecolorbox}
%D
%D Sometimes, especially when we deal with typesetting
%D devices, we want to reverse the color scheme. Instead of
%D recalculating all those colors, we use a quick and dirty
%D approach:
%D
%D \starttyping
%D \negativecolorbox0
%D \stoptyping
%D
%D will negate the colors in box zero.

\def\negatecolorbox#1%
  {\setbox#1\hbox
     {\startnegativeproperty % might change
      \startcolor[white]\vrule\!!height\ht#1\!!depth\dp#1\!!width\wd#1\stopcolor
      \hskip-\wd#1%
      \box#1%
      \stopnegativeproperty}}

%D There are in principle two ways to handle overprint: bound to colors
%D or independent. For the moment we only support independent overprint
%D handling. Here we deal with a per-document setting.

\unexpanded\def\startcolorintent[#1]%
  {\pushattribute\colorintentattribute
   \dotriggercolorintent{#1}}

\unexpanded\def\stopcolorintent
  {\popattribute\colorintentattribute}

\unexpanded\def\startoverprint{\startcolorintent[\v!overprint]}
\unexpanded\def\stopoverprint {\stopcolorintent}

\unexpanded\def\startknockout {\startcolorintent[\v!knockout ]}
\unexpanded\def\stopknockout  {\stopcolorintent}

\let\starttextcolorintent\relax
\let\stoptextcolorintent \relax

\setupcolors
  [\c!overprint=\v!no]

\appendtoks
    \dosettextcolorintent
\to \everysetupcolors

\def\dosettextcolorintent
  {\doifnot\@@clintent\v!none
     {\xdef\starttextcolorintent{\noexpand\dotriggercolorintent{\@@clintent}}%
      \glet\dosettextcolorintent\relax
      \dotriggercolorintent\@@clintent}}

\appendtoks \starttextcolorintent \to \everystarttextproperties
\appendtoks \stoptextcolorintent  \to \everystoptextproperties

\setupcolors[\c!intent=\v!none]

% A goodie that replaces the startMPcolor hackery
%
% \definecolor[red-t]  [r=1,t=0.5,a=1]
% \definecolor[green-t][g=1,t=0.5,a=1]
% \defineintermediatecolor[mycolora][0.5,red,green]
% \defineintermediatecolor[mycolorb][0.5,red-t,green-t]
% \starttext
%     test {\mycolora OEPS} test
%     test {\mycolorb OEPS} test
% \stoptext

\unexpanded\def\defineintermediatecolor
  {\dotripleempty\dodefineintermediatecolor}

\def\dodefineintermediatecolor[#1][#2][#3]% \dotripleempty adds {} inside []
  {\dododefineintermediatecolor[#1][#2][#3]}

\def\dododefineintermediatecolor[#1][#2,#3,#4][#5]%
  {\ifconditional\collectcolorsinlist\collectcolorinlist{#1}\fi
   \ctxlua{colors.defineintermediatecolor("#1","#2",
     \thecolorattribute{#3},\thecolorattribute{#4},
     \thetransparencyattribute{#3},\thetransparencyattribute{#4},
     "#5",false,\iffreezecolors true\else false\fi)}% not global
   \dodefinecolorcommand\setvalue{#1}}

\protect \endinput