Function perfect_resize 

pub fn perfect_resize(
    src: ImgRef<'_, u8>,
    dst_width: usize,
    dst_height: usize,
    filter: KnownFilter,
) -> ImgVec<u8>

Generate the mathematically perfect resize output for a given filter.

Uses separable 2D resize: horizontal pass then vertical pass. Edge handling is clamp (repeat edge pixel).