\setupoutput[dvipdfmx]

\setupcolors[state=start]

\definecolor[Header-A][s=.8]
\definecolor[Header-B][darkblue]
\definecolor[Header-C][darkred]

\startuniqueMPgraphic{HeaderOne}
  path p;
  p = fullcircle xscaled \overlaywidth yscaled \overlayheight;
  circular_shade(p,0,\MPcolor{Header-A},\MPcolor{Header-B});
\stopuniqueMPgraphic

\startuniqueMPgraphic{HeaderTwo}
  path p;
  p = unitsquare xscaled \overlaywidth yscaled \overlayheight;
  linear_shade(p,0,\MPcolor{Header-A},\MPcolor{Header-C});
\stopuniqueMPgraphic

\defineoverlay[HeaderOne][\uniqueMPgraphic{HeaderOne}]
\defineoverlay[HeaderTwo][\uniqueMPgraphic{HeaderTwo}]

\starttext

\framed[frame=off,offset=.5em,background=HeaderOne]{\white\tfd Circular Shade}

\blank

\framed[frame=off,offset=.5em,background=HeaderTwo]{\white\tfd Linear Shade}

\stoptext
