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Re: [CSS3, Backgrounds and Borders Module] some questions about border-radius

From: Zack Weinberg <zweinberg@mozilla.com>
Date: Sat, 22 Aug 2009 23:58:46 -0700
To: Andrew Fedoniouk <news@terrainformatica.com>
Cc: W3C Emailing list for WWW Style <www-style@w3.org>
Message-ID: <20090822235846.01a51987@trurl>
Andrew Fedoniouk <news@terrainformatica.com> wrote:
> div.case10
>        {
>          width:10%;
>          height:60px;
>          border:30px solid;
>          border-radius: 60px/20px;
>        }
> ?
> 
> I am getting this (content updated):
> http://www.terrainformatica.com/w3/round-corners-sciter.png
> 
> Cool of course but is the right way of doing this?

What we want to be saying, for the inner-edge-is-a-sharp-corner case,
is something like this: draw lines outward from the inner corner,
continuing the line segments of the inner edge, until they intersect
the outer edge.  The gradient must be inside the region so defined.
I think this is what the current wording means, but it *is* confusing,
and my revision isn't the right fix -- as this example shows, the
transition might *not* be supposed to cover all of the area with a
curved outer border.

I've added another case to my diagram.


> >> I believe that the only reasonable type of gradient here is so
> >> called conic gradient. Probably it makes sense to define just
> >> that?  
> > 
> > I'd call that out of scope for Level 3.  There are several shipping
> > implementations that do sharp transitions.
> 
> I am not asking to remove optionality of gradient.

Sorry, I misunderstood you.  I agree that a conical gradient is
appropriate in the abstract, but I do not want to write an exact
mathematical description of the gradient to use into the spec,
there isn't a convenient other spec to refer to (neither SVG nor PDF
appears to define conical gradients), and it doesn't seem fair to
implementers to give them neither of those.

zw

corner-transition-diagram.svg
(image/svg+xml attachment: corner-transition-diagram.svg)

Received on Sunday, 23 August 2009 06:59:47 GMT

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