[pstricks] transparency

[Pedro Jorge Caridade]

Hi all

Has far has I know, standard postscript don't have a transparency
option. Right? Is there any chance to make some kind of a copy of a
region and simulate some transparency. Like the mixing colors example of
Dennis.

The goal of it is to emphasize some region of a pspicture, for example
with a psframebox, putting the rest in gray (some transparent overlay)

Pedro