AssetBundleGraphTool custom filter class/Filter by texture's alpha channel info

FilterByTextureAlpha.cs

using UnityEngine;
using UnityEditor;

using System;
using System.Linq;
using System.IO;
using System.Collections.Generic;
using System.Reflection;
using System.Text.RegularExpressions;

using UnityEngine.AssetBundles.GraphTool;
using Model=UnityEngine.AssetBundles.GraphTool.DataModel.Version2;

[CustomFilter("Filter By Texture Alpha")]
public class FilterByTextureAlpha : IFilter {

	[SerializeField] private bool m_hasAlpha;

	public string Label { 
		get {
			return m_hasAlpha ? "With Alpha" : "No Alpha";
		}
	}

	public FilterByTextureAlpha() {
		m_hasAlpha = false;
	}

	public bool FilterAsset(AssetReference a) {

		if(a.filterType != typeof(TextureImporter)) {
			return false;
		}

		var textureImporter = AssetImporter.GetAtPath(a.importFrom) as TextureImporter;

		return textureImporter.DoesSourceTextureHaveAlpha() == m_hasAlpha;	
	}

	public void OnInspectorGUI (Action onValueChanged) {

		using (new EditorGUILayout.HorizontalScope()) {
			var newValue = EditorGUILayout.ToggleLeft("Texture has Alpha channel", m_hasAlpha);

			if (newValue != m_hasAlpha) {
				m_hasAlpha = newValue;
				onValueChanged();
			}
		}
	}
}