wxGameyuexiu/Assets/FollowUI.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class FollowUI : MonoBehaviour
{
    public RawImage follow;

    // Update is called once per frame
    void Update()
    {
        float bl2 = (float)Screen.height / follow.texture.height;

        this.GetComponent<RectTransform>().sizeDelta = new Vector2(follow.texture.width, this.GetComponent<RawImage>().texture.height);
        this.transform.localScale = new Vector3(bl2, bl2, bl2);
    }
}