Function index_colors

pub fn index_colors<Pix, Map>(
    image: &ImageBuffer<Pix, Vec<u8>>,
    color_map: &Map,
) -> ImageBuffer<Luma<u8>, Vec<u8>>
where
    Map: ColorMap<Color = Pix> + ?Sized,
    Pix: Pixel<Subpixel = u8> + 'static,

Reduces the colors using the supplied color_map and returns an image of the indices