Feature request: allow \mpcolor to define color

[chupinmaxime]

\mpcolor only works with withcolor. Is that possible to allow it to define color? In my LuaLaTeX code, I wrote a function with xcolor to get the specs (\extractcolorspecs) and convert (\convertcolorspec) any LaTeX color to rgb metapost color codage.

[chupinmaxime]

up?

[dohyunkim]

You can make your own macro like this:

\documentclass{article}
\usepackage{luamplib,xcolor}
\def\mympcolor#1{%
  runscript" %
    tex.runtoks(function() %
      tex.sprint[[\string\extractcolorspecs{#1}\string\tmpa\string\tmpb %
      \string\convertcolorspec{\string\tmpa}{\string\tmpb}{rgb}\string\tmpc]] %
    end) %
    return string.format('(\csstring\%s)', token.get_macro'tmpc') %
  "
}
\begin{document}
\begin{mplibcode}
  color reddish;
  reddish := \mympcolor{red!50} ;
  beginfig(0);
  fill fullcircle scaled 20 withcolor reddish ;
  endfig;
\end{mplibcode}
\end{document}

[chupinmaxime]

Tank you, I’ve done something like that too, but I think that it would be nice to adapt the macro \mpcolor.

[dohyunkim]

It's not possible to adapt \mpcolor without redefining withcolor operator. Instead, v2.29 provides mplibtexcolor and mplibrgbtexcolor operators which can be used in color definitions (or other places that accept color expressions). I hope the latter one fits your request. If you feel the name is too long, you can declare let mpcolor = mplibrgbtexcolor; somewhere in the metapost code and use mpcolor thereafter.

[chupinmaxime]

That’s great thank you.