Function sdl2::gfx::imagefilter::shift_right_and_mult_by_byte

pub fn shift_right_and_mult_by_byte(
    src1: CVec<u8>, 
    n: u8, 
    c: u8
) -> Result<CVec<u8>, String>

Filter using ShiftRightAndMultByByte: D = saturation255((S >> N) * C).