Function image::imageops::sample::thumbnail_sample_fraction_horizontal

fn thumbnail_sample_fraction_horizontal<I, P, S>(
    image: &I,
    left: u32,
    fraction_horizontal: f32,
    bottom: u32,
    top: u32
) -> (S, S, S, S)where
    I: GenericImageView<Pixel = P>,
    P: Pixel<Subpixel = S>,
    S: Primitive + Enlargeable,

Get a thumbnail pixel where the input window encloses at least a vertical pixel.