Subject: IPP> MOD - Suggestion: add RequiredResources call to Windows GDI to help drivers emit IPP job submission input parameters

From: Tom Hastings <[email-masked]>
Date: Tue, 1 Apr 1997 14:03:09 PST

Babak,

The last IPP meeting was an opportunity for all parties in the printing
food chain to get together and discuss problems.  As we discussed, IPP
is attempting to (1) continue to cater to the current predominant printing
paradigm of an application generating GDI calls to the operating system
which either produces a print data stream to a printer or video to a
screen transparently to the application program and (2) enable a new
printing paradigm of printing pre-formatted documents that need not be
resident on the desktop machine any time during the process 
(print-by-reference using URLs to the documents).

In so doing, IPP seeks to separate the print job instructions from the
document data.  Such a separation causes a problem for print drivers
in that they are not aware of all the resources that a document needs
until the last GDI call.  By document resources, I'm including: media, fonts,
color, etc.  Therefore, the print driver has a problem outputting the print 
job instructions, including resource requirements, up front in the IPP 
protocol.  While spooling the document on the client allows a second pass
(the unspool) to copy the document resources that the Printer driver 
recordrf at the end of the document to the front of the IPP
stream on its way to the IPP printer, we'd like to evolve towards not
requiring client spooling to support IPP.

When I discussed this problem with you at the IPP meeting, you suggested that
I write an Email note to you suggesting a new function call be added to the
GDI in which an application could declare up front all the resources that
the document needs.  Then an IPP print driver could convert such a call to
the proper IPP job level instructions when printing.  This new GDI call
would also be useful for other printing protocols as well.

So here is that Email, belately.

Also the above discussion may want to be added to the IPP Model up front
under 2. Simplified Printing Model.

Thanks,
Tom

---

From: [email-masked]
Date: Sat, 05 Apr 1997 16:24:34 +0200

Tom,
naive question:
Does the IPP print model have to include the possibility of the first
portion of the document being printed before the request is completely
sent to the printer?

If not, why not design the protocol so that resource requirements can
be attached to the *end* of the print request?

OTOH, I personally think that it would probably be better in version
1.0 to take the "do or die approach": let the human or driver negotiate
some resources (like A4 paper) up front, and then the job either prints
or crashes. Just make sure the error report is right..... There's no
way I can think of where one can negotiate on *every* resource one
can think of - for instance, some *ancient* PostScript printers allowed
you to put 68000 machine code into PostScript files; do you want to
include negotiation on the CPU type in the printer?

KISS.....

                 Harald A