W3C home > Mailing lists > Public > www-style@w3.org > August 2009

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

From: Zack Weinberg <zweinberg@mozilla.com>
Date: Mon, 24 Aug 2009 10:19:11 -0700
To: fantasai <fantasai.lists@inkedblade.net>
Cc: Andrew Fedoniouk <news@terrainformatica.com>, W3C Emailing list for WWW Style <www-style@w3.org>
Message-ID: <20090824101911.40b46c81@trurl>
fantasai <fantasai.lists@inkedblade.net> wrote:
> Andrew Fedoniouk wrote:
> > There are three possible cases of the area where gradient
> > transition may happen. They are presented on this figure:
> > 
> > http://www.terrainformatica.com/w3/border-radius-transition-areas-fig.png
> > Variant (C) (gradient area is limited by rectangle-intersection of
> > two borders) will not work as such rectangle can be outside of the
> > curve completely - no area to do transition at all.
> Thank you for the great illustrations Andrew, I understand better
> what the argument is here.
> The intention of the spec is to limit transitions to area B.
> This is because the conjunction of different styles may need
> the full area of B. 

Well, I believe you, but I could really use an example.  I cannot think
of a circumstance where you would need the additional area provided by
B, even for border-style transitions.  Also (as I said previously) the
text doesn't sound like it specifies B to me.

I see you changed the wording and picked up my diagram, but my diagram
is illustrating C, and the wording is now even more confusing to me :-(

> If you're just joining two solid borders
> and want to do a color transition, you wouldn't want to use
> the full area of B, you'd want to draw lines through the border
> from the ends of the inner curve to the ends of the outer curve.
> In the case where the inner curve is a sharp corner, you draw
> angled lines through the border from the point to the ends of
> the curve on the outer edge. 

The possibility of the transition boundary lines being angled never
occurred to me.  I've updated my diagram again (attached, SVG and PNG
both).  Is this what you had in mind for color transitions?

(Of course you can put my diagrams in the spec!)


p.s. fantasai, if you're in Mountain View this week, we could talk
about this in person.

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

(image/png attachment: corner-transition-diagram.png)

Received on Monday, 24 August 2009 17:19:58 UTC

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