[tex-eplain] fcolorbox misses fbox

[Helmut Jarausch]

Hi,

I've tried to use \fcolorbox from the color package.
This fails with an unknown \fbox macro unless I add the code below.

I have blindly copied these macros from  
/usr/share/texmf-dist/tex/latex/base/latex.ltx

Is there a more eplain friendly definition of \fbox ?

Many thanks for a hint,
Helmut


\beginpackages
\usepackage{color}
\endpackages
\makeatletter
\def\@frameb at x#1{%
   \@tempdima\fboxrule
   \advance\@tempdima\fboxsep
   \advance\@tempdima\dp\@tempboxa
   \hbox{%
     \lower\@tempdima\hbox{%
       \vbox{%
         \hrule\@height\fboxrule
         \hbox{%
           \vrule\@width\fboxrule
           #1%
           \vbox{%
             \vskip\fboxsep
             \box\@tempboxa
             \vskip\fboxsep}%
           #1%
           \vrule\@width\fboxrule}%
         \hrule\@height\fboxrule}%
                           }%
         }%
}
\long\def\fbox#1{%
   \leavevmode
   \setbox\@tempboxa\hbox{%
     \color at begingroup
       \kern\fboxsep{#1}\kern\fboxsep
     \color at endgroup}%
   \@frameb at x\relax}
\makeatother

\pagecolor{black}   % schwarzer Seitenhintergrund
\color{red}         % roter Text
\definecolor{gray}{gray}{.5}
\fcolorbox{green}{gray}{Box with a green boundary on a gray background  
--- the text is read}
\bye