I'm trying to implement an export to EPS feature (in C++), and I'm using the pdfmark (pdf) extensions for transparency, but I have yet to see them have any effect. I'm using Illustrator 14.0 and GSView 4.9 as clients. Even using this example from Adobe's docs produces no transparency.
%!PS-Adobe-3.0 EPSF-3.0
%%Creator: xan
%%Pages: 1
%%Orientation: Portrait
%%BoundingBox: 0 0 600 600
%%EndComments
%%Page: 1 1
/DeviceCMYK setcolorspace 15 setlinewidth
[ /ca .6 /CA .3 /BM /Normal /SetTransparency pdfmark
0 1 1 0 setcolor 220 330 150 0 360 arc fill % red
0 0 1 0 setcolor 320 503 150 0 360 arc fill % yellow
1 1 0 0 setcolor 420 330 150 0 360 arc fill % blue
1 0 0 0 setcolor 230 440 104 0 360 arc stroke % cyan
0 1 0 0 setcolor 410 440 104 0 360 arc stroke % magenta
0 0 1 0 setcolor 320 284 104 0 360 arc stroke % yellow
%%EOF
Is there another flag I need to set? Or is it just a problem with these clients?