[Bf-committers] Color space and alpha issues

[Troy Sobotka]

On Dec 15, 2011 11:50 PM, "Bartek Skorupa" <bartekskorupa at bartekskorupa.com>
wrote:
>
> Re wiki page: When explaining math behind mixing "Over" image with
> background (straight alpha) it should be: [(Over.RGB * Over.Alpha) +
> (Background.RGB * (1 - Over.Alpha))].
> Formula at the page is: [(Over.RGB * Over.Alpha) + Background.RGB].
> Shouldn't it be corrected?
>

Yes. It was my oopsie in a hasty attempt to illustrate that premultiplied
alpha actually changes the over operation. It allows for luminescent
additive pixels with an alpha of zero.

I will try to fix it from my phone.