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use crate::lerp::Lerp;
use crate::Blend;
use pix::{Alpha, Channel, Mask};
impl<C, A> Blend for Mask<C, A>
where
C: Channel + Lerp,
A: Alpha<Chan = C>,
A: From<C>,
{
fn over_fallback<B: Blend>(dst: &mut [Self], src: &[B], clr: Self)
where
Self: From<B>,
{
for (bot, top) in dst.iter_mut().zip(src) {
let s = clr * Into::<Self>::into(*top);
*bot = Blend::over(*bot, s);
}
}
fn over(dst: Self, src: Self) -> Self {
let t = src.alpha().value();
let value = dst.alpha().value().lerp(t, t);
Mask::new(value)
}
}