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Re: [CSS3 Backgrounds] border-radius open issues: clipping and gradients

From: Bert Bos <bert@w3.org>
Date: Mon, 3 Dec 2007 15:37:01 +0100
To: www-style@w3.org
Message-Id: <200712031537.02118.bert@w3.org>

On Friday 30 November 2007 05:10, fantasai wrote:
> For the issues
>    "Border images specified with 'border-image', however, are clipped
> at the outer edge of the curve. Or are they not affected at all?" and
>    "Mention that background images are clipped at the outer edge or
> the rounded corner."
>
>   I suggest that border-image not be affected at all. If the author
> wants that clipped, he can do it in the image editing program. Not
> clipping it ourselves lets him use border-radius as a fallback for a
> more complicated silhouette.

Yes, that sounds right.

>
>   Suggested edits:
>
>   I recently added the following paragraph in response to the Beijing
> F2F resolutions:
>
>     # The inner border radius is the outer border radius minus the
>     # corresponding border thickness. In the case where this results
> in a # negative value, the inner radius is zero. (In such cases its
> center # might not coincide with that of the outer border curve.)
>
>   We can change "inner border radius" to "padding edge (inner border)
> radius". and then add
>
>     | Backgrounds, but not the border-image, are clipped to the curve
>     | of the border.

Agreed.

>
> For the issue
>    "If the two adjoining borders have different colors? A color
> gradient might look nice, but should we require it?"
>
>   I suggest we recommend, but not require, a color gradient.

Yes, I think a gradient will look reasonable in all cases, and as 
computers get more powerful and graphics libraries easier to use, I 
expect we'll see more and more UAs follow the recommendation.

>
>
> For the issue
>    "[Ben Stucki] Is there a need for a property to allow the designer
> to select between smooth color gradient and cut off at 45 degree? The
> latter would also cut off a rounded corner of which one side has zero
> thickness."
>
>   I suggest that this can be added in CSS4 if it's found to be
> necessary. I suspect that it won't be in high demand.

Right. With the ability to use a border image, there is already a way 
around the limitation for all but the most demanding cases.



Bert
-- 
  Bert Bos                                ( W 3 C ) http://www.w3.org/
  http://www.w3.org/people/bos                               W3C/ERCIM
  bert@w3.org                             2004 Rt des Lucioles / BP 93
  +33 (0)4 92 38 76 92            06902 Sophia Antipolis Cedex, France
Received on Monday, 3 December 2007 14:37:14 GMT

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