UnityImageProcessing_Package/Scripts/Editor/Windows/ImageProcessingGraphEditorWindow.cs

using System;
using UnityEditor;
using UnityEditor.Experimental.GraphView;
using UnityEngine;

namespace ImageProcessingGraph.Editor.Windows
{
    public class ImageProcessingGraphEditorWindow : EditorWindow
    {
        [SerializeField] private ImageProcessingGraphAsset currentGraph;
        [SerializeField] private SerializedObject serializedObject;
        [SerializeField] private ImageProcessingGraphViewWindow currentView;
        public ImageProcessingGraphAsset CurrentGraph => currentGraph;

        public static void Open(ImageProcessingGraphAsset asset)
        {
            ImageProcessingGraphEditorWindow[] windows = Resources.FindObjectsOfTypeAll<ImageProcessingGraphEditorWindow>();

            foreach (var w in windows)
            {
                w.Focus();
                return;
            }

            ImageProcessingGraphEditorWindow window =
                CreateWindow<ImageProcessingGraphEditorWindow>(typeof(ImageProcessingGraphEditorWindow),
                    typeof(SceneView));
            
            window.titleContent = new GUIContent($"{asset.name}", EditorGUIUtility.ObjectContent(null, typeof(ImageProcessingGraphAsset)).image
            );
            window.Load(asset);
        }

        void OnEnable()
        {
            if(currentGraph != null)
                DrawGraph();
        }

        private void OnGUI()
        {
            if (currentGraph != null)
            {
                if(EditorUtility.IsDirty(currentGraph))
                    this.hasUnsavedChanges = true;
                else
                    this.hasUnsavedChanges = false;
            }
        }

        public void Load(ImageProcessingGraphAsset asset)
        {
            currentGraph = asset;
            DrawGraph();
        }

        public void DrawGraph()
        {
            serializedObject = new SerializedObject(currentGraph);
            currentView = new ImageProcessingGraphViewWindow(serializedObject, this);
            currentView.graphViewChanged += OnChange;
            rootVisualElement.Add(currentView);
        }

        private GraphViewChange OnChange(GraphViewChange graphviewchange)
        {
            EditorUtility.SetDirty(currentGraph);
            return graphviewchange;
        }
    }
}