Fade method
Get color with alpha applied, alpha goes from 0.0 to 1.0
Implementation
@override
ColorD Fade(
ColorD color,
double alpha,
) => $.Color$.Extract2(
(p) => _ffi.Fade(
$.Color$.Ref1(color).asNativePointer<ColorC>().ref,
alpha,
).toDart(p.asNativePointer()),
);