Per <http://lists.w3.org/Archives/Public/www-style/2009Jul/0048.html>, we should interpolate colors by first converting them to premultiplied alpha. This avoids the 'fade through gray' when animating from 'transparent' to an opaque color.
Created attachment 47779 [details]
Comment on attachment 47779 [details]
It’s scary that Color can be either premultiplied or non-premultiplied.
*** Bug 34334 has been marked as a duplicate of this bug. ***
Why not fixing premultipliedARGBFromColor directly? It affects other parts (mainly Cairo for what it was introduced) too.
premultipliedARGBFromColor is related to bug 30333