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Re: [css3-images] Probably Editorial: radial-gradient() and concentric ellipses

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.)

How about "uniformly scaled" instead of "proportional"?

Øyvind Stenhaug
Core Norway, Opera Software ASA
Received on Wednesday, 29 February 2012 18:23:09 UTC

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