Subject: Re: IPP> Re: draft-mutz-http-attributes-02.txt

From: Neil Joffe <[email-masked]>
Date: Fri, 06 Jun 1997 13:44:20 -0700

At 12:42 PM 6/6/97 -0700, Robert Herriot wrote:
>
>> From [email-masked] Thu Jun  5 19:32:57 1997
>> 
>> > None of these solutions solve the problem of the Printer's 
>> > resolutions-supported attribute which, hopefully, tells the
>> > client exactly what resolutions the Printer supports without
>> > any extraneous values and without a complicated structure
>> > for the attribute.
>> 
>> I think this is the same problem fax has, though.
>> Why would a list of pairs of integers (x-res/y-res)
>> or integer & ratio (x-res, aspect ratio) have 'extraneous
>> values'? Or be a 'complicated structure'?
>> 
>
>If there are attributes x-res and y-res, then according to the IPP
>model, there must be an x-res-supported and a y-res-supported in the
>Printer.  Suppose the printer supports 300 and 300x600 and 600 Then
>both x-res-supported and y-res-supported have values of 300 and 600.
>Then x-res and y-res can have any of the following 4 values 300x300,
>300x600, 600x600 and 600x300.  The last value is not a legitimate value
>according to my original statement.
>
>It may be that resolutions supported by real printers and all future
>printers can never have this problem. For example if the values are 300
>and 300x600, then x-res-supported is 300 and y-res-supported is 300 and
>600. No illegal combinations are possible with these values.
>
>That's the problem I have with the x-res, y-res solution.  If you can
>show my that this solution cannot lead to unsupported combinations,
>then I would agree that a pair of integers is possibly a better solution.

You will need to specify the following pairs:
x-res=300, y-res=300
x-res=300, y-res=600
x-res=600, y-res=600

or maybe

x-res=600, y-res=600
x-res=300, y-res>=xres

>Bob Herriot

------------------------------------------------------------------------
Neil Joffe                                     Email:  [email-masked]
Software Engineer                        Voice:  +1 (408) 527-7957
Voice Technology Engineering     Fax:     +1 (408) 527-3907
Cisco Systems
San Jose
------------------------------------------------------------------------

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From: Carl-Uno Manros <[email-masked]>
Date: Fri, 6 Jun 1997 16:17:04 PDT

>You will need to specify the following pairs:

Maybe I am too simplistic here, but it seems that everybody in this
discussion is assuming that the values have to be numeric and hence we have
to a x-value and a y-value.

Why not stay with a simple approach of using ASCII text strings, and just
define ONE attribute with the value for the attribute being a simple text
string allowing values like:

"300x300"
"300x600"
"600x600" etc

with an additional rule that what comes before the "x" is the x-value and
what comes after it is the y-value.  

This could also allow for cases like:

"300"

which would be semantically equivalent to:

"300x300"

Comments?

Carl-Uno

Carl-Uno Manros
Principal Engineer - Advanced Printing Standards - Xerox Corporation
701 S. Aviation Blvd., El Segundo, CA, M/S: ESAE-231
Phone +1-310-333 8273, Fax +1-310-333 5514
Email: [email-masked]