Rotation animation moves obect's xy

Hi people,
need help, please. I'm trying to animate an object. The animation changes the y position by transform. What happens though is that when I rotate it, it moves its pivot position, thus offsets the whole object.

Here's the video:

And the code:

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class AttackAnimation : MonoBehaviour
6. {
7.     public float offset = 0.0f;
8.     private Animator _attackAnimation= null;
9.  
10.     private Vector3 center;
11.     // Start is called before the first frame update
12.     void Start()
13.     {
14.         _attackAnimation = GetComponent<Animator>();
15.     }
16.  
17.     // Update is called once per frame
18.     void Update()
19.     {
20.         // Use this for initialization
21.         bool attack = false;
22.  
23.         //turn to cursor possition
24.         center = Camera.main.ScreenToWorldPoint(GetComponent<SpriteRenderer>().sprite.pivot);
25.  
26.         Vector3 difference = Camera.main.ScreenToWorldPoint(Input.mousePosition) - transform.position;
27.         difference.Normalize();
28.  
29.         float rotation_z = Mathf.Atan2(difference.y, difference.x) * Mathf.Rad2Deg;
30.         transform.rotation = Quaternion.Euler(0f, 0f, rotation_z + offset);
31.  
32.  
33.         if (Input.GetMouseButton(0))
34.         {
35.             attack = true;
36.         }
37.  
38.         _attackAnimation.SetBool("attack", attack);
39.  
40.         GetComponent<SpriteRenderer>().sprite.pivot = center;
41.     }
42. }
43.  

I should add that the code GetComponent<SpriteRenderer>().sprite.pivot = center; throws an error as the sprite.pivot is read only. No idea how to set it.

Tx very much!
V

 

OK, I fixed it by moving the rotation script to the parent object. This is it

.