Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!newstop!exodus!bendenweyr!flar
From: flar@bendenweyr.Eng.Sun.COM (Jim Graham)
Newsgroups: comp.lang.postscript
Subject: Re: Byte's fern postscript program
Message-ID: <1990Oct23.131527@bendenweyr.Eng.Sun.COM>
Date: 23 Oct 90 20:15:27 GMT
References: <1990Oct18.182149.861@infonode.ingr.com> <1990Oct19.160619@bendenweyr.Eng.Sun.COM> <5830@munnari.oz.au>
Sender: news@exodus.Eng.Sun.COM
Reply-To: flar@bendenweyr.Eng.Sun.COM (Jim Graham)
Distribution: na
Organization: Sun Microsystems, Inc.
Lines: 41

In article <5830@munnari.oz.au>, danielce@ecr.mu.oz.au (Daniel Ake
Massimo Paolo Carosone) writes:

|> In article <1990Oct19.160619@bendenweyr.Eng.Sun.COM>
|> flar@bendenweyr.Eng.Sun.COM (Jim Graham) writes:

|> >In article <1990Oct18.204534.9186@julius.cs.uiuc.edu>,
|> >nelson@melodian.cs.uiuc.edu (Taed Nelson) writes:
|> >
|> >> [Some PS code involving rlineto]
|> >
|> >What am I missing here?  In the first repeat loop, a lot of moveto
|> >rlineto's get generated but the result is never stroked or filled,
|> >it is just thrown away with a newpath.  What's the point (only side
|> >effect that I can see is the execution of 20 rand's, so it essentially
|> >just throws out 20 random numbers and takes a long time to do it.
|> 
|> But it *does* move the Current Point. There is *no* gsave ... grestore,
|> so this has the effect of going through the IFS transformations,
|> and eventually places ink at the appropriate places..

Not only is a newpath executed (which tosses the currentpoint), but the
code in the following repeat loop does a moveto before each rlineto, so
the currentpoint after the first repeat loop would be meaningless even
if it weren't destroyed by newpath.  So, the question still remains:
What does the first loop do?

|> /doit {
|>         problistcreate 1 1 20 {
|>                 problist rand -24 bitshift get transform 2 copy
|>                 moveto 0.001 10 rlineto
|>         }
|>         repeat newpath numdots {
|>                 problist rand -24 bitshift get transform 2 copy
|>                 moveto 0.001 0 rlineto stroke
|>         }
|>         repeat
|> }
|> bind def

					...jim