From: Øyvind Stenhaug <oyvinds@opera.com>
Date: Wed, 29 Feb 2012 19:22:26 +0100
To: "Kang-Hao (Kenny) Lu" <kennyluck@csail.mit.edu>
Cc: "WWW Style" <www-style@w3.org>
Message-ID: <op.wagdbofdbunlto@oyvinds-desktop>
```On Wed, 29 Feb 2012 18:17:41 +0100, Kang-Hao (Kenny) Lu
<kennyluck@csail.mit.edu> wrote:

> (12/03/01 0:58), Øyvind Stenhaug wrote:
>> On Tue, 28 Feb 2012 17:16:28 +0100, Tab Atkins Jr.
>> <jackalmage@gmail.com> wrote:
>>> Yup, everyone does the obvious thing.  I've added the word
>>> "proportional" in front of "concentric ellipses".  That sound good?
>>
>> I think you'd need a further restriction. As I understand it, a radial
>> gradient consists of all ellipses E such that
>> 1) E and the ending shape are concentric - that is, they have the same
>> center
>> 2) E and the ending shape have the same eccentricity - I assume this is
>> what "proportional" means, though using that word when talking about
>> two-dimensional shapes sounds unfamiliar to me (I didn't use the term
>> "similar" since that has a non-mathematical meaning which is much more
>> vague)
>> 3) the major semiaxes/radii of E and the ending shape coincide
>> (otherwise you'd include ellipses that are rotated by any arbitrary
>> amount)
>
> Well, in some sense "proportional" could be interpreted as "scaled
> proportionally" (so no roation involved and hence it covers 3) ) so I
> found Tab's tweak satisfactory. Most importantly, it doesn't seem to be
> necessary to confuse readers with mathematicl terms like "eccentricity"
> and "semiaxes/radii" when the interoperability problem this vagueness
> might cause is pretty theoretical.

Right, I didn't mean to suggest an actual wording, and I agree that it's a
relatively minor and theoretical issue. (Though in general I think
exactness should trump briefness and readability for non-technical
readers, for the normative sections. I'd prefer not to have to interpret
and guess what the writer meant.)