NodeGraphProcessor - NodeView with texture preview example

MapOutputNodeView.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEditor;
using UnityEditor.UIElements;
using UnityEditor.Experimental.GraphView;
using UnityEngine.UIElements;
using GraphProcessor;

[NodeCustomEditor(typeof(MapOutputNode))]
public class MapOutputNodeView : BaseNodeView {
  protected new MapOutputNode nodeTarget => base.nodeTarget as MapOutputNode;

  private VisualElement previewContainer;
  private Texture2D previewTexture;

  public override void Enable() {
    var node = nodeTarget as MapOutputNode;

    previewContainer = new VisualElement();
    controlsContainer.Add(previewContainer);
    controlsContainer.Add(new Label("Run for preview"));
    nodeTarget.onProcessed += UpdatePreview;
  }

  private void UpdatePreview() {
    if (nodeTarget.output == null || nodeTarget.output.GetLength(0) == 0 || nodeTarget.output.GetLength(1) == 0) {
      return;
    }
    if (previewContainer != null && previewContainer.childCount == 0) {
      CreatePreviewContainer();
    }

    // Update the actual texture.
    var data = nodeTarget.output;
    var width = data.GetLength(0);
    var height = data.GetLength(1);
    previewTexture = new Texture2D(width, height, TextureFormat.RGB24, false);
    for (int x = 0; x < width; x++) {
      for (int y = 0; y < height; y++) {
        previewTexture.SetPixel(x, y, data[x, y] == 0 ? Color.white : Color.black);
      }
    }
    previewTexture.Apply();
  }

  private void CreatePreviewContainer() {
    previewContainer.Clear();
    var mapTexture = new VisualElement();
    previewContainer.Add(mapTexture);
    mapTexture.Add(new IMGUIContainer(() => {
      var previewRect = GetPreviewRect();
      EditorGUI.DrawPreviewTexture(previewRect, previewTexture);
    }));
  }

  private Rect GetPreviewRect() {
    float width = controlsContainer.contentRect.width;
    float scaleFactor = width / nodeTarget.output.GetLength(0);
    float height = Mathf.Min(width, nodeTarget.output.GetLength(1) * scaleFactor);
    return GUILayoutUtility.GetRect(1, width, 1, height);
  }
}