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Re: [css3-background] suggestion of alternate method for drawing shadows

From: ben <arcticmac@comcast.net>
Date: Tue, 17 May 2005 03:40:40 +0000
Message-Id: <a06200705beaf14c7c166@[]>
To: Matthew Raymond <mattraymond@earthlink.net>
Cc: www-style@w3.org

>    No. Alpha suggests a rendering method for shadows involving 
>drawing a shape with a certain alpha value on top of whatever is 
>behind the element casting the shadow. This means that a red shadow 
>with 100% opacity would be just a red box behind the element.
>    The color of a real shadow, however, is the result of ambient 
>light. Therefore, a red shadow should be a multiplication of the 
>background color and the ambient light color (assuming both are sets 
>of three floating point numbers between 0.0 and 1.0).
>    Well, yeah, elements under the shadowing element should have the 
>shadow cast on top of them.

Cool... that's even better, just so elements under the shadowing 
element have the shadow cast on top of them.

>    Well, I'd like to agree with you, but what happens when you have 
>a lot of elements with alpha values inside of an element with a 
>shadow? It could get very hard to code very quickly.

Well, the elements with alpha values inside the element with the 
shadow wouldn't get their own shadows unless they had shadow 
specified, would they?  And my guess is that it's not hard to code, 
but that it'd take longer to render...   I don't know offhand how 
alpha values affect contained elements.  It would probably depend on 
how that's being done.  hm...
Received on Thursday, 28 July 2005 15:22:16 UTC

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