Unity Editor Change UI Scale Factor With Game View

code.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using UnityEngine;
using UnityEditor;
using UnityEditor.SceneManagement;
using UnityEngine.UI;

[InitializeOnLoad]
public class EditorUIScaler {
    static EditorUIScaler() {
        var assembly = typeof(UnityEditor.EditorWindow).Assembly;
        var gameViewType = assembly.GetType("UnityEditor.GameView");
        var playModeViewType = assembly.GetType("UnityEditor.PlayModeView");
        var targetSizeField = playModeViewType.GetField("m_TargetSize", BindingFlags.NonPublic | BindingFlags.Instance);
        EditorWindow gameView = null;

        CanvasScaler[] canvases = null;
        EditorApplication.delayCall += () => {
            gameView = EditorWindow.GetWindow(gameViewType);
            canvases = EditorSceneManager.GetActiveScene().GetRootGameObjects().Where((g) => g.name.EndsWith("Canvas"))
                .Select((g) => g.GetComponent<CanvasScaler>()).ToArray();
        };

        EditorApplication.update += () => {
            if (gameView && canvases != null && !EditorApplication.isPlaying) {
                var size = (Vector2)targetSizeField.GetValue(gameView);
                foreach (var canvas in canvases) {
                    canvas.scaleFactor = size.x * 0.7f / 1920;
                }
            }
        };
    }
}