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Re: [css3-background] box-shadow spread radius and rounded corners

From: Brad Kemper <brad.kemper@gmail.com>
Date: Wed, 28 Apr 2010 20:16:18 -0700
Cc: Brian Manthos <brianman@microsoft.com>, www-style@w3.org
Message-Id: <97F16CE2-48FA-46E0-B7A3-966A909343AD@gmail.com>
To: Alex Meiburg <timeroot.alex@gmail.com>

On Apr 28, 2010, at 6:40 PM, Alex Meiburg wrote:

> Then, the shadow would add something like 5px to each radius

No, it just follows the radius in the same way that it follows the straight parts. So does the blur, for that matter. For instance, take a look at this, where you can see the difference between a sharp corner and a heavily blurred one (no spread in either):


Now look at this image, where the white has been changed to yellow, so that you can clearly see the extent of the blurred area:


This shows that the blur area has extended the boundary of the shadow out 25px, and created a shape with a 50px corner radius! Yet no one is complaining about how it increases the radius from 0 to 50px. This is the same sort of thing that spread does, but with a solid colored brush instead of a fuzzy-edged brush. In fact it is what 'border' does too, but no one complains about it having inner radii that are different from the outer radii. Border is more like inner shadow, in that the radius of the inner part gets smaller than the specified part, but that's just because the spec says to apply the radius to the outside of the border instead of the inside. It could just as easily have gone the other way.

Received on Thursday, 29 April 2010 03:17:00 UTC

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