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From: rb@ccird1.UUCP (Rex Ballard)
Newsgroups: net.micro.68k
Subject: Re: CD ROMs to use 68000 OS9
Message-ID: <397@ccird1.UUCP>
Date: Fri, 2-May-86 21:55:07 EDT
Article-I.D.: ccird1.397
Posted: Fri May  2 21:55:07 1986
Date-Received: Tue, 6-May-86 03:38:23 EDT
References: <808@ihwpt.UUCP> <1185@lsuc.UUCP> <994@amiga.amiga.UUCP> <821@ihwpt.UUCP> <798@ccird2.UUCP> <17626@rochester.ARPA>
Reply-To: rb@ccird1.UUCP (Rex Ballard)
Distribution: net
Organization: CCI Rochester Development, Rochester NY
Lines: 46
Summary: Graphics Interchange VDI

In article <17626@rochester.ARPA> crowl@rochester.UUCP (Lawrence Crowl) writes:
>In article <798@ccird2.UUCP> rb@ccird2.UUCP (Rex Ballard) writes:
>>... [Storing on CD-ROMs] things like ... with illustrations ...
>
>Egads!  Is there a standard for storing images?  Are they pixel based?
>Will they fit on my screen?
>
>>... In addition, OS-9 has a VDI interface for presentation graphics, ...
>
>Will this deal with images, or graphics command sequences?
>-- 

Well, I can't tell too much from the "product announcement", but
it looks like the VDI can be build under either bit-map images,
or command sequences.  The announcement was for the 63484 VDI
driver.  Appearantly, they also have 7220 and bitmap versions
as well.  Basicly, the VDI approach used in OS-9 allows one
to treat incoming and outgoing graphics commands as "streams".

Even Unix, you could easily "cat pictures/bear |plot".  All a VDI
does is set things like clipping so that you can send "pictures"
to different parts of the screen.  This basicly allows you to
use a single screen without knowing where in the "real" screen
you are.

As to the VDI interpretations, the just announced PD "superplot"
package provides several options for getting from the CD to the
"work-station".  Options include postscript, plot(3) streams,
or Tektronics, among others.  Postscript is beginning to look
attractive because it allows building of "macros" like "rounded
rectangle", if it is not already part of the package.  It isn't
hard to convert from any of these "interchange formats" to your
local "VDI" interface.  Often, little more than a simple translation
table is all that is required.

There are a few PD programs which will "interpret" these streams
into C routines (which are translated into system calls) as well.

After looking at the GEM(Atari,IBM,et. al.), and Mac VDI
specifications,  I doubt it would be very difficult to come
up with the apropriate interface.

The important thing to remember about a CD VDI interface, is that
you don't actually edit them directly.  You do, however need to
get editable "Units" and preferrable "Groups" which can be manipulated
with an editor.