using UnityEngine;
using UnityEngine.UI;

public class FullScreen : MonoBehaviour
{
    [SerializeField] CanvasScaler canvasScaler;
    [SerializeField] Vector2 adding = new Vector2(0, 0);

    Vector2 prevScreenSize = Vector2.zero;

    private void OnEnable()
    {
        Apply();
        prevScreenSize = new Vector2(Screen.width, Screen.height);
    }

    private void LateUpdate()
    {
        if (prevScreenSize.x != Screen.width || prevScreenSize.y != Screen.height)
        {
            Apply();
            prevScreenSize = new Vector2(Screen.width, Screen.height);
        }
    }

    private void Apply()
    {
        var rt = transform as RectTransform;
        var csRt = canvasScaler.transform as RectTransform;

        rt.pivot = new Vector2(0.5f, 0.5f);
        rt.anchorMin = new Vector2(0.5f, 0.5f);
        rt.anchorMax = new Vector2(0.5f, 0.5f);

        rt.anchoredPosition = Vector2.zero;
        rt.sizeDelta = new Vector2(csRt.sizeDelta.x + adding.x, csRt.sizeDelta.y + adding.y);
    }
}