ソースコード

using System;
using UnityEngine;

namespace Kogane
{
    [DisallowMultipleComponent]
    internal sealed class GameViewMaximizedChecker : MonoBehaviour
    {
#if UNITY_EDITOR

        private UnityEditor.EditorWindow m_gameView;
        private bool                     m_maximized;

        public event Action OnChanged;

        private void Awake()
        {
            var assembly = typeof( UnityEditor.EditorWindow ).Assembly;
            var type     = assembly.GetType( "UnityEditor.GameView" );

            m_gameView  = UnityEditor.EditorWindow.GetWindow( type );
            m_maximized = m_gameView.maximized;
        }

        private void Update()
        {
            if ( OnChanged == null ) return;
            if ( m_maximized == m_gameView.maximized ) return;

            m_maximized = m_gameView.maximized;

            OnChanged();
        }
#endif
    }
}