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Re: [css3-background] color transition line

From: Simon Fraser <smfr@me.com>
Date: Tue, 01 Nov 2011 10:01:39 -0700
Cc: www-style@w3.org
Message-id: <5A512CF5-6B82-40FB-9E24-FCCCB14B73DB@me.com>
To: Řyvind Stenhaug <oyvinds@opera.com>
On Nov 1, 2011, at 9:05 AM, Řyvind Stenhaug wrote:

> On Tue, 01 Nov 2011 14:54:26 +0100, Brad Kemper <brad.kemper@gmail.com>
> wrote:
> 
>>> I think you're reading it as "use the angle an indicator of the location along the partial ellipse of the outer curve, do the same with the inner curve, and connect the dots".
>> 
>> I believe that was the intention.
>> 
>> I thought this meant that for a 45deg ray, "the point on the curve" would be where 45deg was perpendicular to the tangent. Is that not right? It has been a long time since I have been in a geometry class, and describing a point on a curve as an angle has just never come up in any of my conversations since then.
>> 
>> The third rendering doesn't look to me like it is where a 45deg angle would bisect the outer curve at a place where a tangent to the curve would be perpendicular to that angle.
> 
> OK, the above doesn't really make sense to me, but the "tangent" part provides a hint to interpreting the spec in a different way. So it's supposed to pick a point on the border edge curve where the slope is a certain number, then the same for the padding edge curve, and the transition center is a line segment joining those two points? Then maybe t17-tangent.png is actually what the spec intends to say, though nobody's actually implemented that. Not sure it makes sense to choose that slope independently of the border radii, either.

That seems hard to implement. What WebKit does is illustrated here:
<https://bug-9197-attachments.webkit.org/attachment.cgi?id=30423>

What's wrong with that approach?

Simon
Received on Tuesday, 1 November 2011 17:02:41 GMT

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