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[I tried to mail you but "cn@allgfx.agi.oz" bounced]

cn@allgfx.agi.oz (Con Neri) writes:

>I am trying to implement a generalised pattern fill in postscript but am having
>a few problems. I am implementing a methods similar to prog 15 in the blue book
>but with larger patterns. It seems that with the larger patterns the frequency
>passed to the setscreen operator is ignored and some default value is used.
>There are no errors generated at all and the point at which the expected 
>frequency and the true frequency differ is different for a different device of
>the same resolution., ie

>	LaserWriter
>	LaserWriter +
>	DataProducts 1200
>	Hyphen Software Rip (@300 dpi).

>Can someone please shed some light on this phenomena? Has anybody else done
>any serious work with patterns? Please either e-mail or send to this group. If
>there is enough response I will summarise.

(Message inbox:12)
(Message inbox:12)

From:    MAILER-DAEMON@cwi.nl (Mail Delivery Subsystem)
Subject: Returned mail: Host unknown

Date:    Mon, 17 Dec 90 11:04:41 +0100
To:      jansteen@cwi.nl



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Received: by piring.cwi.nl via EUnet; Mon, 17 Dec 90 11:04:41 +0100
Date: Mon, 17 Dec 90 11:04:41 +0100
From: jansteen@cwi.nl (Jan van der Steen)
Message-Id: <9012171004.AA19293@piring.cwi.nl>
To: cn@allgfx.agi.oz
Subject: Re: Patterns
Newsgroups: comp.lang.postscript
References: <1990Dec16.223249.26946@allgfx.agi.oz>

In comp.lang.postscript you write:


>I am trying to implement a generalised pattern fill in postscript but am having
>a few problems. I am implementing a methods similar to prog 15 in the blue book
>but with larger patterns. It seems that with the larger patterns the frequency
>passed to the setscreen operator is ignored and some default value is used.
>There are no errors generated at all and the point at which the expected 
>frequency and the true frequency differ is different for a different device of
>the same resolution., ie

>	LaserWriter
>	LaserWriter +
>	DataProducts 1200
>	Hyphen Software Rip (@300 dpi).

>Can someone please shed some light on this phenomena? Has anybody else done
>any serious work with patterns? Please either e-mail or send to this group. If
>there is enough response I will summarise.

The setscreen operator is *heavily* device dependant. The higher the
resolution of the output device the better the results though.
To get a nice overview of the capabilities of your specific output
device you should obtain (please feel free to mail me) an article +
testfile by Margo Schulter titled "Screen test".



    Jan van der Steen

-- 
    -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
     Jan van der Steen                 jansteen@cwi.nl
     Centre for Mathematics and Computer Science (CWI)
     Kruislaan 413, 1098 SJ Amsterdam, The Netherlands
--
    -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
     Jan van der Steen                 jansteen@cwi.nl
     Centre for Mathematics and Computer Science (CWI)
     Kruislaan 413, 1098 SJ Amsterdam, The Netherlands