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Re: [css3-images] Premultiplication switch (was: gradient pre-multiplied interpolation)

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Wed, 27 Jul 2011 13:31:26 -0700
Message-ID: <CAAWBYDCoSYe22MngLGY-EVym751dU9B64_+P4V3Zd1y3COim4g@mail.gmail.com>
To: Brian Manthos <brianman@microsoft.com>
Cc: Chris Lilley <chris@w3.org>, Leif Arne Storset <lstorset@opera.com>, "www-style@w3.org" <www-style@w3.org>
On Wed, Jul 27, 2011 at 10:46 AM, Brian Manthos <brianman@microsoft.com> wrote:
> Chris Lilley:
>> TAJ> I believe a better approach would be to augment SVG's
>> TAJ> color-interpolation property with options for switching between
>> TAJ> premultiplied and non-premultiplied.  That way other things could
>> TAJ> potentially switch as well, like transitions.
>>
>> I agree that is a better approach. Currently the color-interpolation
>> property selects between colour spaces. It would be possible to add a
>> premultipliedRGB value. Note that conversion into a premultiplied
>> colourspace does result in loss of colour precision as the opicity
>> decreases.
>
> The color-interpolation property proposal...
>
> Can we see a sample possible syntax?  I'd like to get a feel for how it behaves across rules (vs. across the page as a top-level switch).

Well, the color-interpolation property is defined by SVG already at
<http://www.w3.org/TR/2003/REC-SVG11-20030114/painting.html#ColorInterpolationProperties>.
 If we were to extend it, I'd imagine it looking something like:

color-interpolation: auto | [ [sRGB | linearRGB] premultiplied? ]

While we're fiddling with it, I could also see adding hsl-cw and
hsl-ccw (the direction specifies what to do when the hues are
separated by 180deg) to the sRGB/linearRGB set of colorspaces.

~TJ
Received on Wednesday, 27 July 2011 20:32:21 GMT

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