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Re: box-shadow and features (was [css3-background] Issues and Proposed Resolutions)

From: Brad Kemper <brkemper@comcast.net>
Date: Thu, 15 May 2008 00:48:59 -0700
Cc: fantasai <fantasai.lists@inkedblade.net>, www-style@w3.org
Message-Id: <7C246BDE-03D4-4472-A6A5-375BBA7A0DC4@comcast.net>
To: Alan Gresley <alan@css-class.com>


On May 14, 2008, at 4:46 PM, Alan Gresley wrote:

>
> fantasai wrote:
>> Alan Gresley wrote:
>>>
>>>> Inner Box Shadow:
>>>>  http://www.w3.org/Style/CSS/Tracker/issues/44 ISSUE-44
>>>>
>>>>  There have been quite a few comments about adding such a feature,
>>>>  or at least an "inner glow" feature (which this would address).
>>>
>>>
>>> If an inner glow/shadow is added (ISSUE-44) to CSS3, the only  
>>> place for the inner (whatever?) to be placed is inside the border- 
>>> box. This box would have to have a transparent background but this  
>>> could not happen if shadows were not allowed to be drawn inside  
>>> the border-box (ISSUE-32).
>> If an inner glow/shadow were added, then it would be painted inside  
>> the
>> padding box and not outside it. This is analogous to the way the  
>> outer
>> shadow is painted outside the border box and not inside it. :)
>
>
> Well doesn't that mean the inner glow/shadow is painted above the  
> background instead of how box-shadow works normally? :-)

If I understand you correctly, it would be, but I don't understand the  
objection. It would create a stacking context in the box, similar to  
the way opacity does. The element's background would be underneath the  
inner shadow. It is not that different conceptually from outer  
shadows, except that it is the negative space that is casting the  
effect instead of the positive space.

>>> Why can't box-shadow be painted the same way as shadows or  
>>> highlight occur naturally. How are authors suppose to create depth  
>>> of field if box-shadow doesn't work like true shadows or highlights?
>> It seems more common to mask the shadow than to not mask it. Also, if
>> a true shadow is wanted then it would make more sense to apply the
>> effect to the whole element the same way 'opacity' works. That would
>> be a different property.
>
>
> Firstly you can mask the box by giving the box an opaque background,  
> like blue. Opacity doesn't just effect the box but the contents of  
> the box like text and what happen with the stacking order and z-index?

z-index only effects the element as a whole, and not the stacking  
order of its sub-elements (sub-elements like background colors,  
multiple background images, border images, borders, internal shadows,  
etc.).

>
>
>
>>> How can spread work if backgrounds are always opaque?
>> See http://bradclicks.com/cssplay/Shadows.html
>> ~fantasai
>
>
> What about a spread that go inside the box.

What about it? I don't understand your point. There are some of those  
shown on the page referenced above, and also at this one with borders  
and translucent shadows (think rgba):

http://bradclicks.com/cssplay/Shadows2.html

>
>
>
> Alan
>
>
Received on Thursday, 15 May 2008 07:49:43 GMT

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