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Re: [CSS4 color][CSS4 transition] color pre-multiplied vs non pre-multiplied was (Re: [CSSWG] Minutes TPAC Tue 2012-10-30 AM I: Abstract Directions, Transforms, Transitions)

From: Brad Kemper <brad.kemper@gmail.com>
Date: Fri, 1 Feb 2013 06:50:51 -0800
Message-Id: <15468AC0-26CE-46E1-9273-9213969AD6BA@gmail.com>
Cc: Rik Cabanier <cabanier@gmail.com>, Alan Gresley <alan@css-class.com>, fantasai <fantasai.lists@inkedblade.net>, "www-style@w3.org" <www-style@w3.org>
To: Simon Fraser <smfr@me.com>
On Jan 31, 2013, at 11:18 PM, Simon Fraser <smfr@me.com> wrote:

> We rely on Core Graphics to render gradients on Mac, and that can't do pre-multiplied. That's the main reason why gradients don't match transitions.

If I understand correctly, this means that if an author wants a nice clean-looking 3-stop gradient that goes from yellow to transparent to blue, he will have to use two same-position transparent color stops, so that it is actually yellow to transparent-yellow, and then transparent-blue to blue. Couldn't WebKit just perform this extra conversion step for us before passing it on to Core Graphics?
Received on Friday, 1 February 2013 14:51:22 GMT

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