By native do you mean APA, or 2250 et al? The data streams manual does discuss 
APA. I don't know of any GGDM support for other than PSS and APA.

I checked bitsavers for 3179G and couldn't find it. If anybody still has the 
manual, please scan it. Thanks.


--
Shmuel (Seymour J.) Metz
http://mason.gmu.edu/~smetz3

________________________________________
From: IBM Mainframe Discussion List [IBM-MAIN@LISTSERV.UA.EDU] on behalf of 
Greg Price [greg.pr...@optusnet.com.au]
Sent: Wednesday, April 28, 2021 9:50 AM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: Re: And the survey says...

On 28/04/2021 2:33 am, Seymour J Metz wrote:
> GDDM and PGF are the primary programs for 3270 graphics. I don't know whether 
> SAS Graph requires GDDM.

Well, I've coded programmed symbols and I've coded some native vector
graphics, but I don't know the protocols to code PC-LINK graphics. I
gather the latter is where the host offloads more of the work to the
workstation.

The spec for programmed symbols is documented in the 3270 Data Stream
Programmer's Reference, but for the other two you'd probably need to do
a VTAM trace of GDDM terminal I/O to figure out.

Native vector graphics used to be documented in the 3179G book, but that
disappeared after the 3179G was discontinued. (If anyone has one they'd
like to sell then please let me know.) I'd say it is very close to the
codes that GDDM uses itself internally.

If you have a 3270 graphics application that could be made to work with
GDDM then I'd recommend you do so because then you can let GDDM figure
out which graphics protocol to use for any given terminal and how to
convert your requests to the appropriate data stream orders.  I would
guess that SAS Graph would call GDDM, but that's just a guess.

I've "assisted" (badgered?) two TN3270 client authors in adding
programmed symbol graphics support to their products (really just
clarified the spec and provided testing feedback). One decided the
potential for support cases wasn't worth the effort/risk, and the other
(Nexus Terminal) has retained it in the product.

As someone said, Nexus is very fast, and the support is very responsive
to customers.

(Disclaimer: Both TN3270 client authors generously waived the fee to
allow me to use their products, both of which are of excellent quality.)

The REVIEW command (available from CBT and elsewhere - release 50 should
be coming out soon) has some code to render bitmaps (.BMP, .PCX, .GIF)
on 3270 graphics screens (LPS and native vector graphics only) without
using GDDM.  (GDDM will be called for PC-LINK.) Don't expect true-color
rendering. Haven't tested large pictures lately, but small ones work
pretty well AFAICT.

Cheers,
Greg

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