Subject: Re: Comments on draft-ietf-conneg-media-features-02.txt

From: Graham Klyne <[email-masked]>
Date: Wed, 23 Sep 1998 20:01:08 +0100

At 19:28 23/09/98 +0200, Koen Holtman wrote:

>Section 2.2: 
>
>dpi values are supposed to be 'rational'. You give the example
>dpi=19558/100 which is a fraction.  I an quite surprised by this
>because I thought that rational meant 'floating point', as in
>dpi=195.58 .  I guess maybe this is more of a registration draft
>problem.

I always understood "rational" to mean "expressible as a ratio of two
integers" (which includes all fractions and non-recurring decimals), as
opposed to "irrational" that means numbers like SQRT(2) and PI and E that
cannot be so expressed.

>Section 2.5:
>
>Delete the n/a entries, like in the other sections.
>
>Section 3:
>
>In the examples you use notation like 'pix-x<=1024'.  I believe the
>strange symbol <= here is a remnant of an earlier TCN syntax.  Current
>TCN does not use that syntax anymore.  In any case I think that using
>plain = in the examples makes them work much better as examples.

I think I agree for here, but I'd also point out that the -algebra- draft
explicitly allows the use of '<=' and '>=' operators for defining feature
sets.

>I would prefer it if a 'textonly' tag were added, for two reasons:

A good point for discussion.  (A not-very-elegant alternative might be to
offer very low resolutions based on character cell size.)  But mainly, I
think that if one introduces 'textonly' then also needed are ways to
describe the display area size in terms of characters, and/or indicate
character font sizes, and/or indicate other characteristics of character
terminals (overstrike? underline?).

>(textonly=true would mean that the recipient is not capable of
>rendering graphics content, either inlined in HTML or self-contained)

... or a document that does not contain graphic content.

BTW, this is another example of a feature like the earlier font example:
within the current -algebra- framework, if a recipient specifies
'textonly=true' and a document does not specify any value for 'textonly'
then the feature sets can be matched.

#g

------------
Graham Klyne
([email-masked])

---

From: [email-masked] (Koen Holtman)
Date: Mon, 28 Sep 1998 19:09:31 +0200 (MET DST)

>opposed to "irrational" that means numbers like SQRT(2) and PI and E that

Do you assume any standard notation for rational numbers?

[....]
>terminals (overstrike? underline?).

I do not feel that 'textonly' necessarily leads to tags for the
display size in characters.  To me 'textonly' would also include
things like speech and braille devices.  So this tag is not about
fine-tuning representations, it is about labling the version of a web
page which is most suited for conversion by a speech device etc.  

I guess that most web sites would only provide a single textonly
version of a page, if any.  Nobody would sub-negotiate on things like
overstrike.

>Graham Klyne

Koen.