convert postscript file to eps file that is in a vector format

Question

I want to generate an eps file (.eps) that contains vector data rather than rasterized data. I am trying to do so by converting a postscript file (.ps) into an eps file using ps2eps like so:

ps2eps asdf.ps

However this results in a rasterized output. Why is this? How can I get a non rasterized output?

here is the content of the asdf.ps file:

%!PS-Adobe-3.0 EPSF-3.0
%%BoundingBox: 0 0 400 400

% Draw a line
1 setlinewidth
0 0 moveto
200 200 lineto
0 0 1 setrgbcolor
stroke

% Draw a circle
100 100 40 0 360 arc
1 setlinewidth
0 0 0 setrgbcolor
1 setgray
fill
stroke