UPD Mail Archive: RE: UPD> command sequences

RE: UPD> command sequences

From: Sandra Matts (sandram@boi.hp.com)
Date: Wed Feb 16 2000 - 14:50:02 EST

  • Next message: MATTS,SANDRA (HP-Boise,ex1): "FW: UPD> command sequences"

    For fonts I believe we can specify font sequences
    for PCL 5 and PCL 6 and it will work. However,
    for graphics commands using Raster and HP-GL/2,
    I think it will be a bit hard. I will
    have to do some prototyping (later) to see if it will
    work.

    For Fonts I think it is probably our only choice
    because of our tendencies to add proprietary
    escapes.

    Encoding escape sequences in XML may be hard. We can
    reference a binary file of escape sequences (Binary
    ENTITY) or we can use the pre-defined ISO-Latin-1
    Character set. Using the latter would mean a driver
    has to decode Esc* (1B2Ah) to the binary equivalent
    1B2A in hex and send that to the printer. Using
    a binary entity the driver would pull the entry
    from the file and send it to the printer with
    no decoding.

            I would lean towards the former so that
    the driver would not have to have as much intelligence.
    Also it may be difficult to enhance binary definitions
    if we require the driver to know their meaning.

    Sandra Matts

    Sandra Matts
    Engineer Scientist
    Hewlett-Packard
    sandram@boi.hp.com
    208-396-4755 phone
    Boise, ID 83714

    -----Original Message-----
    From: owner-upd@pwg.org [mailto:owner-upd@pwg.org]On Behalf Of Norbert
    Schade
    Sent: Tuesday, February 15, 2000 2:24 PM
    To: UPD group
    Subject: UPD> command sequences

    The more I think about it, the more I am convinced that we need command
    sequences in the UPDF file.
    It is simply an illusion that a driver uses a certain HP model as a
    reference. I really think every clone and every port of a PDL to a specific
    model has its proprietary conditions and even improvements, which are not
    100% compatible with the target HP model.
    >From my time in Germany, where we developed drivers for many different
    companies, I know that a lot of proprietary command sequences have been
    invented in the past and that there are tons of proprietary paper source,
    paper size, print media, typeface, symbol set and other parameters.
    Only very few models would work with a UPD, that anticipates the correctness
    of a print file.

    Beside the difficulties to describe binary print files - are there other
    reasons to not specify command sequences in a UPDF?
    Like marketing or policy reasons?
    In case we solve the problems to describe that technically, has any company
    any other problem?
    Norbert





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