Path: utzoo!attcan!uunet!fernwood!decwrl!shelby!lindy!sumex-aim!chavez
From: chavez@sumex-aim.stanford.edu (R. Martin Chavez)
Newsgroups: comp.sys.next
Subject: Pattern fills in Display Postscript
Message-ID: <7134@lindy.Stanford.EDU>
Date: 12 Jan 90 10:04:38 GMT
Sender: news@lindy.Stanford.EDU (News Service)
Reply-To: chavez@sumex-aim.stanford.edu (R. Martin Chavez)
Organization: Medical Computer Science Group, Stanford University
Lines: 19

My colleagues and I would like to fill PostScript paths with patterns
defined as 8x8 bit matrices.  We need the fill operation to be extremely
fast, and so we'd like to use the halftone mechanism (which would clearly
win over replicated tiling of the region with the pattern).

We're presently using code from the Blue Book that purports to call setscreen
with frequency, angle, and spot-function parameters that accurately represent
predefined bit patterns.  Unfortunately, the results look terrible (and wrong)
on the MegaPixel display, with its 4 gray levels.  Instead of setting pixels
to either black or white, DPS seems to want to choose intermediate values,
with unacceptable results.

We know that FrameMaker has some mechanism (presently unknown to us) for 
filling regions.  Can anyone out there point us to PostScript code that does
the job?

Thanks,
R. Martin Chavez
Stanford University School of Medicine