Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!mailrus!tut.cis.ohio-state.edu!bloom-beacon!mit-eddie!uw-beaver!microsoft!tonyw
From: tonyw@microsoft.UUCP (Tony Williams)
Newsgroups: comp.graphics
Subject: Re: postscript routines for plotting
Message-ID: <1109@microsoft.UUCP>
Date: 27 Oct 88 01:05:18 GMT
References: <31190@bbn.COM> <4357@ubc-cs.UUCP> <7999@gryphon.CTS.COM> <8392@cit-vax.Caltech.Edu>
Reply-To: tonyw@microsoft.UUCP (Tony Williams)
Organization: Microsoft Corp., Redmond WA
Lines: 22

In article <8392@cit-vax.Caltech.Edu> wen-king@cit-vax.UUCP (Wen-King Su) writes:
| I am into chip plotting; I want to plot the various layers of an
| integrated circuit design using different stipple patterns so that
| when two or more layers overlap the union of the patterns produces
| a unique stipple pattern.   Goemetries in each layer are ploted as
| polygons.  Since PostScript does not allow transparent writing of
| polygons (OR-ing a pattern onto a page instead of painting an opague
| pattern over the page, a white dot does not erase a black dot), I
| could not accomplish what I want with PostScript short of rasterizing
| the whole thing and sending it to the printer as a bit array or
| compute intersections of the layers and decompose all the polygons,
| both of which are un-acceptibly slow.  Even the most ardent supporters
| of PostScript here has to admit that this is a very serious short-coming
| of the language.  Any suggestions?  I will be very grateful if you
| can help me.

Set the polygon as a clip region.
Draw the black portions of the stipple pattern either explicitly
with lines/dots etc, or using the imagemask operator.

I admit, for certain patterns this might be slow
and/or require replicating the imagemask pattern many times.
   Tony