Re: mask: luminance or alpha

On Tue, Jul 31, 2012 at 4:02 PM, Brian Birtles <birtles@gmail.com> wrote:

> (2012/08/01 6:27), Rik Cabanier wrote:
>
>> So, <auto> means 'alpha' if you point to an image and 'luminosity' if
>> you point to vector data?
>> I think that's reasonable and similar to PDF's soft mask images.
>>
>
> The way it's currently spec'ed is different. <auto> means 'luminance' for
> <mask>s (unless they have maskType="alpha") and 'alpha' elsewhere.
>
> We can change that, however, if we feel the vector vs raster distinction
> is easier for authors (and not just designers).


No, we can't change mask.
Your new proposal [1] states:

autoIf the mask source is a
‘mask<https://svgwg.org/svg2-draft/masking.html#MaskElement>
’ element, the method used for calculating the mask values is determined by
the‘maskType<https://svgwg.org/svg2-draft/masking.html#MaskElementMaskTypeAttribute>
’ attribute on the ‘mask<https://svgwg.org/svg2-draft/masking.html#MaskElement>
’ element. *Otherwise, the alpha values of the mask source should be used
as the mask values.*

The last sentence could be like:

Otherwise, the mask type is luminance except if the mask source is an image
in which case it should be alpha.

1: https://svgwg.org/svg2-draft/masking.html#mask-property