CapersProject/Assets/02.Scripts/AspectRatioController.cs

using System.Collections.Generic;
using UnityEngine;

namespace BlueWater
{
    public class AspectRatioController : MonoBehaviour
    {
        [SerializeField]
        private List<RectTransform> _canvasRectTransforms = new();
        
        private float _targetAspect = 16f / 9f;
        
        private void OnPreCull()
        {
            GL.Clear(true, true, Color.black);
        }

        private void Awake()
        {
            _canvasRectTransforms.Add(SceneController.Instance.Panel.GetComponent<RectTransform>());
            EventManager.OnChangedDisplay += ChangeResolution;
        }

        private void OnDestroy()
        {
            EventManager.OnChangedDisplay -= ChangeResolution;
        }

        private float GetScaleHeight()
        {
            return ((float)Screen.width / Screen.height) / _targetAspect;
        }

        private void SetCamera()
        {
            Camera mainCamera = Camera.main;
            Rect cameraRect = mainCamera.rect;
            float scaleHeight = GetScaleHeight();
            float scaleWidth = 1f / scaleHeight;

            if (scaleHeight < 1f)
            {
                cameraRect.height = scaleHeight;
                cameraRect.y = (1f - scaleHeight) / 2f;
            }
            else
            {
                cameraRect.width = scaleWidth;
                cameraRect.x = (1f - scaleWidth) / 2f;
            }

            mainCamera.rect = cameraRect;
        }
        
        private void AdjustUI()
        {
            float scaleHeight = GetScaleHeight();

            foreach (var element in _canvasRectTransforms)
            {
                if (scaleHeight < 1f)
                {
                    element.anchorMin = new Vector2(0f, (1f - scaleHeight) / 2f);
                    element.anchorMax = new Vector2(1f, 1f - (1f - scaleHeight) / 2f);
                }
                else
                {
                    float scaleWidth = 1f / scaleHeight;
                    element.anchorMin = new Vector2((1f - scaleWidth) / 2f, 0f);
                    element.anchorMax = new Vector2(1f - (1f - scaleWidth) / 2f, 1f);
                }

                element.offsetMin = Vector2.zero;
                element.offsetMax = Vector2.zero;
            }
        }
        
        public void ChangeResolution()
        {
            AdjustUI();
            SetCamera();
        }
    }
}