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[fxtf-drafts] [filter-effects] Luminance coefficients are slightly changed from SVG 1.1

From: Amelia Bellamy-Royds via GitHub <sysbot+gh@w3.org>
Date: Wed, 28 Jun 2017 02:10:12 +0000
To: public-fxtf-archive@w3.org
Message-ID: <issues.opened-239033240-1498615811-sysbot+gh@w3.org>
AmeliaBR has just created a new issue for https://github.com/w3c/fxtf-drafts:

== [filter-effects] Luminance coefficients are slightly changed from SVG 1.1 ==
In response to my griping on Twitter that the `luminosity` used in blend modes isn't compatible with the `luminance` used in Masking and Filters, @nikosandronikos [discovered](https://twitter.com/nandronikos/status/879872647730876416) that the "luminance" coefficients in the [Filter Effects spec](https://drafts.fxtf.org/filters/#attr-valuedef-type-luminancetoalpha) don't match the ones from [SVG 1.1](https://www.w3.org/TR/SVG11/filters.html#feColorMatrixValuesAttribute).

- Filters Level 1: luminance = 0.2126R + 0.7152G + 0.0722B
- SVG 1.1: luminance = 0.2125R +  0.7154G + 0.0721B

The values used in the Filters spec are also incorporated by reference by [CSS Masking](https://drafts.fxtf.org/css-masking-1/#MaskValues).

The difference is slight (~0.01%), but if there was a very good reason for the change (e.g., compatibility with some 3rd standard), there should be a note explaining that.  Otherwise, I'm assuming it was an unintentional error.  

Please view or discuss this issue at https://github.com/w3c/fxtf-drafts/issues/206 using your GitHub account
Received on Wednesday, 28 June 2017 02:10:18 UTC

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