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Date: 8 September 1986, 09:34:05 EST
From: Ton van Overbeek          +31 1719 83041       TPC862   at ESTEC
To:   DOUG at NGP.UTEXAS.EDU
cc:   INFO-ATARI16 at SU-SCORE.ARPA
Subject: Re: Normalized Device Coordinates in TDI Modula-2

>Does the ST support NDC (Normalized Device Coordinates)?  I've seen one
>source that says it doesn't and one that mentions NDC as a possibility,
>which presumably means it does.

No, the Atari roms do not support NDC. Atari/DRI did not have room enough
in the ROM's to include the device independent part of the VDI. That is
also the reason why you cannot load fonts with the standard vdi functions
and why there is no official version of GEM Draw and GEM Write. (They use
the device independent part very much for different output devices).
One solution is to intercept the trap#2 (AES, VDI trap) and supply the
the missing parts of VDI. This is what GDOS does (used by Easydraw).
There have been announcements of an official release of GDOS but I have
not seen it yet.
An excellent background story is in STart, The ST Quarterly, Summer 1986
by Tim Oren: Tracking the elusive GDOS. Get hold of it and read it.
Hope this info is useful

Ton van Overbeek
European Space Research and Technology Centre (ESTEC)
Control Systems Section
P.O.Box 299
2200 AG Noordwijk, The Netherlands.
Phone: +31 1719 83041
Email: TPC862%ESTEC.BITNET@WISCVM.WISC.EDU  (ARPA)
       ...!ucbvax!tpc862@estec.bitnet       (USENET/UUCP)
       TPC862@ESTEC                         (EARN/BITNET)