GHZDaPing/Assets/UIBG.cs

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

public class UIBG : MonoBehaviour
{
    // Start is called before the first frame update
    void Start()
    {
        
        StartCoroutine("check");
    }
    float w;
    float h;
    IEnumerator check()
    {
        while (true)
        {
            yield return new WaitForSeconds(1);
            w = Screen.width;
            h = Screen.height;

            if((float)((float)w/(float)h)<1920f/1080f)
            {
                this.GetComponent<RectTransform>().localScale = new Vector3(w, w * (1080f / 1920f), 1);

            }
            else
            {

                this.GetComponent<RectTransform>().localScale = new Vector3(h * (1920f / 1080f), h, 1);
            }

        }
    }
}