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