# parametric overlay in context

I am trying to make something like excel databars in context TABLE enviroment. I have created overlay, that should draw the databar, but I can't figure out, how to pass data into that overlay.

Is it possible to make something like

\defineoverlay[demo circle #1][\useMPgraphic{demo circle}{color=#1}]


??? or is there any other way, how to draw cell background of TBALE (\bTD) by Metapost and pass in data, that will be accessible by \MPvar?

minimal working example:

\mainlanguage[cz]
\setuppapersize[A4][A4]
\setupcolors[state=start]

\startuseMPgraphic{demo circle}
path p ;
p := fullcircle xscaled \overlaywidth yscaled \overlayheight ;
fill p withcolor .85white ;
draw p withpen pencircle scaled 2pt withcolor \MPvar{color} ;
\stopuseMPgraphic

\defineoverlay[demo circle #1][\useMPgraphic{demo circle}{color=#1}]

\starttext

\placetable{Test}{\bTABLE
\bTR \bTD[background=demo circle blue] aaaaa \eTD \bTD[background=demo circle red] bbbbb \eTD \eTR
\bTR \bTD[background=demo circle green] cccccc \eTD \bTD[background=demo circle black] dddddd \eTD \eTR
\eTABLE}
\stoptext

• Please help us to help you and add a minimal working example (MWE) that illustrates your problem. It will be much easier for us to reproduce your situation and find out what the issue is when we see compilable code, starting with \documentclass{...} and ending with \end{document}. – cfr Dec 28 '14 at 3:58
• @cfr: I agree with the spirit of your comment (the need for a MWE), but note that this is a question related to ConTeXt, so there will be no \documentclass{...} ... \end{document}. – Aditya Dec 28 '14 at 7:25
• @Aditya Oops. Indeed. I cut-and-pasted the standard comment block without thinking about it, but you are obviously right. – cfr Dec 28 '14 at 14:22

The standard way to pass color options to a frame is to use the framecolor key. The value of that key can be accessed using \overlaylinecolor. For example:

\setupcolors[state=start]

\startuseMPgraphic{demo circle}
newpath p ;
p := fullcircle xscaled \overlaywidth yscaled \overlayheight ;
fill p withcolor .85white ;
draw p withpen pencircle scaled 2pt withcolor \MPcolor{\overlaylinecolor} ;
\stopuseMPgraphic

\defineoverlay[demo circle][\useMPgraphic{demo circle}]

\starttext

\placetable{Test}
{\bTABLE
\bTR
\bTD[background=demo circle, framecolor=red]
aaaaa
\eTD
\bTD[background=demo circle, framecolor=red]
bbbbb
\eTD
\eTR
\bTR
\bTD[background=demo circle, framecolor=green]
cccccc
\eTD
\bTD[background=demo circle, framecolor=green]
dddddd
\eTD
\eTR
\eTABLE}
\stoptext


which gives

You can use frame=off to avoid the default frames.