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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 13:27:03 -0700
Message-Id: <512778B8-C7BB-4307-B346-2BD02A14EEB3@gmail.com>
To: Brian Manthos <brianman@microsoft.com>
Cc: "Tab Atkins Jr." <jackalmage@gmail.com>, Sylvain Galineau <sylvaing@microsoft.com>, fantasai <fantasai.lists@inkedblade.net>, "www-style@w3.org" <www-style@w3.org>, Prabs Chawla <pchawla@microsoft.com>
On Apr 28, 2010, at 12:46 PM, Brian Manthos <brianman@microsoft.com>  

> #  The shadow should not change shape when a spread
> # radius is applied: sharp corners should remain sharp.
> As I mentioned earlier, the sentence prior to the colon seems  
> completely incorrect given Brad's description.

You're all just getting hung up on that sentence. I remember when it  
was added, and the point of it was that we wanted to maintain sharp  
corners (thus the explanation after the colon), not to change the  
normal meaning of spread wrt rounded corners.

> Regarding the portion after the colon, it doesn't speak to rounded  
> corners remaining round as such,

Yes, because it was never intended to change how spread worked on non- 
sharp corners.

> Tab's concern becomes ... well ... more pointed for the case of a  
> rounded corners with an inset shadow.
> It's easy to see from the spec Example XXVIII in the 28 April 2010  
> version of http://dev.w3.org/csswg/css3-background/#the-box-shadow.
> If you increase the length parameters by another 5px, the shadow  
> will lose rounding entirely -- it will become sharp.
> I'm surprised this is considered desirable.

But that is what spread is (technically, it is call "choke" in the  
case of inner shadows, but they are two sides of the same coin). That  
is what it does in PhotoShop for shadow effects, where it is often a  
very useful adjustment, and that is the way choking/spreading has  
worked since before there were ever electronic computers.

If you don't find it desirable, you don't have to use it, but it is  
highly desirable to me and many others who are used to applying spread  
and choke this way. 
Received on Wednesday, 28 April 2010 20:27:47 UTC

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