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

From: Alan Gresley <alan@css-class.com>
Date: Thu, 15 May 2008 18:35:06 +1000
Message-ID: <482BF5BA.1080602@css-class.com>
To: Brad Kemper <brkemper@comcast.net>
CC: fantasai <fantasai.lists@inkedblade.net>, www-style@w3.org

Brad Kemper wrote:
> 
> On May 14, 2008, at 4:46 PM, Alan Gresley wrote:
> 
>>
>> fantasai wrote:
>>> Alan Gresley wrote:
>>> 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.


Precisely, a new staking context would be created thus, your inner 
shadow will be stacked higher than the text in the element? This is what 
David was referring about avoiding here.

http://lists.w3.org/Archives/Public/www-style/2008Jan/0483.html


Anyway opacity also effect the text (become lighter) inside the element 
and the stacking context that is created.


>>>> How are authors suppose to create depth of field if 
>>>> box-shadow doesn't work like true shadows or highlights?
>>
>> 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.).


I referring to the whole stacking context and z-index problems where 
shadow and background can not intermingle as they now do in Safari.

If new staking context's was created here and there then this would be 
impossible do to.

http://css-class.com/test/css/shadows/text-shadow-over-elements1.htm


>> 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


Well this is how the minus value for spread would work (I presume). The 
darkest part of the shadow become smaller.


----------------
|              |
|              |
|              |
|       XXXXXXX|XX
|       XXXXXXX|XX
--------X-X-X-X|XX
         XXXXXXXXXX


Thus emulating perspective.


Alan
Received on Thursday, 15 May 2008 08:36:13 GMT

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