pub fn grayscale<I: GenericImageView>(
    image: &I
) -> ImageBuffer<Luma<<<I as GenericImageView>::Pixel as Pixel>::Subpixel>, Vec<<<I as GenericImageView>::Pixel as Pixel>::Subpixel>> where
    <<I as GenericImageView>::Pixel as Pixel>::Subpixel: 'static,
    <<<I as GenericImageView>::Pixel as Pixel>::Subpixel as Num>::FromStrRadixErr: 'static, 
Expand description

Convert the supplied image to grayscale