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Re: Mask property syntax and CSS <image>

From: Brian Birtles <bbirtles@mozilla.com>
Date: Tue, 07 Aug 2012 11:14:53 +0900
Message-ID: <50207A1D.6060805@mozilla.com>
To: Rik Cabanier <cabanier@gmail.com>
CC: public-fx@w3.org
Hi Rik,

(2012/08/07 11:02), Rik Cabanier wrote:
>        mask: url(#circleElem); // alpha
>
>     and, likewise,
>
>        mask: linear-gradient(...); // -webkit-mask makes this alpha
>        mask: url(#gradientElem); // alpha
>
>
> I don't follow this. Why do these 3 examples use alpha?

Ignore the first example. I think we're going to require using element() 
syntax for directly referencing SVG elements as image mask sources so 
the first example is invalid.

The second one, 'linear-gradient()' uses a default of alpha for two reasons:

* Because -webkit-mask does. That's not such a big concern to me but 
obviously if we change this behaviour it makes it harder for content 
authors who are relying on the current behaviour of -webkit-mask to 
transition to the new behaviour.

* More importantly, for implementers it means that all <image> values 
can be treated the same (since gradients are a type of <image> value).

For the third example, IF we decide that a CSS gradient defaults to 
alpha, then I think we should be consistent when pointing to an SVG 
gradient.

> I think we need feedback from designers/tool makers.

That would be good, as well as web developers and other content authors.

> I know many designers use the same outlines of artwork as a mask. My
> fear is that since luminosity is not the default and misunderstood, it
> will end up not being implemented.

That's an important consideration. However, I think all major browser 
vendors have already implemented luminosity for SVG though so we should 
be ok right?

Brian
Received on Tuesday, 7 August 2012 02:15:40 GMT

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