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Re: [CSS-3] outline-style: glow

From: Andrew Fedoniouk <news@terrainformatica.com>
Date: Tue, 15 Apr 2008 11:33:14 -0700
Message-ID: <4804F4EA.8090000@terrainformatica.com>
To: Brad Kemper <brkemper@comcast.net>
CC: Bert Bos <bert@w3.org>, www-style <www-style@w3.org>

Brad Kemper wrote:
> On Apr 15, 2008, at 5:31 AM, Bert Bos wrote:
>> On Tuesday 15 April 2008 01:03, Andrew Fedoniouk wrote:
>>> I propose to add new value of 'glow' to the list of outline-style
>>> values.
>>> Glow is an outline where color intensity (opacity of outline-color)
>>> is a function of distance.
>>> Usually glow is made by applying Gaussian 2d filter to pixels of some
>>> image.
>>> Here is a sample of rendering elements with outline-style:glow;
>>> http://www.terrainformatica.com/w3/outline-glow-sample.png
>> The Backgrounds and Borders draft[1] has a 'box-shadow' property, which 
>> can create similar effects. It's subject to 'z-index' and drawn in a 
>> layer of the element behind the background. That means that there is 
>> some control over its stacking; unlike 'outline', which is always in 
>> front.
> What's missing from Backgrounds and Borders is a way to specify what 
> PhotoShop calls "spread" (in both shadows and glows), which is a way 
> to make the radius of the shadow or glow offset from the edge of the 
> element, and thus larger (without being blurrier). It seems 
> like Andrew's proposal does have that, if I understand it correctly.
Brad, your understanding of it is right.
All graphics editors that have glow effect allow you to define 
curvature/form of the glow filter.
outline-offset/outline-width interpretation I proposed allow to define 
most common cases.

Speaking about shadow: to be able to define shadow effects we just need 
to add one more attribute:
   outline-shift: X Y; (or outline-position)

And one more thing: shadow and outline shall not change dimensions of 
the border box of the element.
And yet, shadow and outline should not be limited only by boxes. So 
proposed outline style is more universal -
it will cover box-shadow[1] and text-shadow[2] and will do it 
better/more flexible.

[1] http://www.w3.org/TR/css3-background/#the-box-shadow
[2] http://www.w3.org/TR/css3-text/#text-shadow

Andrew Fedoniouk.
Received on Tuesday, 15 April 2008 18:34:04 UTC

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