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

From: Sylvain Galineau <sylvaing@microsoft.com>
Date: Wed, 28 Apr 2010 20:06:09 +0000
To: Brad Kemper <brad.kemper@gmail.com>
CC: Tab Atkins Jr. <jackalmage@gmail.com>, fantasai <fantasai.lists@inkedblade.net>, "www-style@w3.org" <www-style@w3.org>, "Brian Manthos" <brianman@microsoft.com>, Prabs Chawla <pchawla@microsoft.com>
Message-ID: <045A765940533D4CA4933A4A7E32597E2145EF57@TK5EX14MBXC111.redmond.corp.microsoft.com>
Brad, I don't understand what is 'extreme' about my example or why it's more extreme than your own. But by playing
with increasing spread values in both Opera and Firefox - which, as far as I can tell, implement spread radius as you
and Elika define it - then I do reach a point where the shadow's shape is very different from that of the box
being shadowed, as well as that of previous less spread-out shadows.

For example, using Opera 10.5x and Firefox 3.6.x : 

		#ref {
			width:50px;
			height:50px;
			margin:200px;
			border: 1px solid black;
			border-radius: 5px;
			-moz-border-radius: 5px;
			box-shadow: 0 0 0 10px blue, 0 0 0 50px green, 0 0 0 160px red;
			-moz-box-shadow: 0 0 0 10px blue, 0 0 0 50px green, 0 0 0 160px red;
		}

>From the blue to the green and then the red shadow, is the shadow surface being evenly expanded
in all directions ? I think the answer is yes and I gather from your feedback that this is what
spreading is supposed to do. But has the *shape* of the shadow been preserved all along ? I don't
get that part at all. The outer edge of each of the shadows is visibly different from that of 
any of the other shadows, never mind the outer border edge box being shadowed.

So it seems I was like Simon: I didn't understand what spreading was. And then inferred it
from a requirement to preserve shape when a spread radius is applied, requirement I do not see 
being fulfilled with an even surface spread.

I think an example like the one above annotated with arrows may be helpful in clarifying the meaning 
of spread radius and I can try to produce one. Most importantly, what shape is being preserved, or 
how it is preserved ought to be clarified. Maybe it's just a matter of making it clear that *only* sharp 
corners retain their border-radius ?
Received on Wednesday, 28 April 2010 20:06:46 GMT

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