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Re: feColorMatrix type="saturate"

From: Erik Dahlstrom <ed@opera.com>
Date: Tue, 27 Sep 2011 16:59:07 +0200
To: www-svg@w3.org
Message-ID: <op.v2g2ktlageuyw5@localhost.localdomain>
On Sat, 24 Sep 2011 22:22:04 +0200, David Dailey  
<ddailey@zoominternet.net> wrote:

> The spec says that for feColorMatrix and ' For type="saturate",
> <http://www.w3.org/TR/SVG/filters.html#feColorMatrixValuesAttribute>
> 'values' is a single real number value (0 to 1).'
>
>
> Opera, however seems to have come up with a very nice and intuitive
> extension of the range outside those values --see
>
>
> http://granite.sru.edu/~ddailey/svg/filter1b.svg -- FF, Chrome and Safari
> don't attempt to render the last two images with my "goofy" values.
>
>
> On the other hand, type="saturate" provides, on an intuitive, level a  
> way of
> saturating and desaturating an image (without having to rely on matrix
> math).
>
>
> Values above 1.0 should, as Opera does, oversaturate the image. Values  
> under
> 0 should reflect the chroma (but not the luminance? If I see what is  
> going
> on here).
>
>
> Maybe something little and easy to consider for 2.0? A single valued
> parameter that does the work of a whole matrix seems like an improvement  
> for
> authors.

What Opera does is to use the equations already in the spec for computing  
the matrix, they are defined for values outside the 0..1 range too.


-- 
Erik Dahlstrom, Core Technology Developer, Opera Software
Co-Chair, W3C SVG Working Group
Personal blog: http://my.opera.com/macdev_ed
Received on Tuesday, 27 September 2011 14:59:41 GMT

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