double atF64(int i0, {int? i1, int? i2}) => i1 == null ? ccore.cv_Mat_get_f64_1(ref, i0) : (i2 == null ? ccore.cv_Mat_get_f64_2(ref, i0, i1) : ccore.cv_Mat_get_f64_3(ref, i0, i1, i2));