[whatwg] Canvas gradients color interpolation - change to premultiplied?

Tab Atkins Jr. jackalmage at gmail.com
Sun Nov 28 10:04:06 PST 2010

On Fri, Nov 26, 2010 at 8:44 PM, Boris Zbarsky <bzbarsky at mit.edu> wrote:
> On 11/26/10 11:39 PM, Simon Fraser wrote:
>>> But CSS gradients are already requiring interpolation in premutiplied
>>> space, right?
>> I think you're thinking of CSS Transitions, which we decided should run in
>> premultiplied.
> No.  http://dev.w3.org/csswg/css3-images/#color-stop-syntax currently says:
>  Between two color-stops, the line's color is linearly interpolated
>  between the colors of the two color-stops, with the interpolation
>  taking place in premultiplied RGBA space.
> and there was related discussion on www-style, iirc.

Note, though, that that's a relatively recent change that I made based
on dbaron's feedback.  That said, in the thread where I made the
change, Simon expressed that he'd like Transitions and Gradients to
work the same way, and I read him as preferring premultiplied.


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