Hi Greg

I was just pointed to this document: [1].
Definitely not the 3179G book you mentioned, but it seems to contain 
information related to 3270 vector graphics. Maybe it helps.

-Alex

[1] https://www.slac.stanford.edu/vault/collvault/greylit/cgtm/CGTM205.pdf

On Wed, Apr 28, 2021 at 11:50:33PM +1000, Greg Price wrote:
> 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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