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Re: SVG masking, maskType attribute still necessary?

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Fri, 17 Aug 2012 11:13:08 -0700
Message-ID: <CAAWBYDA1VN70uJN=fKhJcosNLP4OxDK9sjRuCofM__4OE=dXmQ@mail.gmail.com>
To: Dirk Schulze <dschulze@adobe.com>
Cc: "www-svg@w3.org list" <www-svg@w3.org>
On Fri, Aug 17, 2012 at 11:04 AM, Dirk Schulze <dschulze@adobe.com> wrote:
> Hi SVG WG,
>
> We added the 'maskType' attribute to differ between alpha and luminance masks on the SVG 'mask' element. IIRC we didn't thought about extending the 'mask' property. Since we added the keywords 'alpha' and 'luminance' to the 'mask' property, it seems unnecessary to add a new attribute to the 'mask' element.
>
> Do we want to revert the decision on adding this attribute?

No.  The purpose of the maskType attribute is to signal what the mask
is designed for.  Using the alpha of a mask designed for luminance is
almost certainly a mistake and will likely produce bad and confusing
results.

The purpose of the keyword on the property is to signal whether to use
alpha or luminance on things *other than* <mask> elements, because
they can't signal what they were designed for.

If I recall correctly, the keyword on the property is meant to have no
effect on a <mask> element, because the maskType attribute is the
source of truth there.

~TJ
Received on Friday, 17 August 2012 18:13:55 GMT

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