update

Assets/SharedAssets/Scripts/Editor/GradientTexture.cs

@@ -0,0 +1,103 @@
+using System;
+using System.Collections.Generic;
+using UnityEngine;
+
+[CreateAssetMenu(fileName = "GradientTexture", menuName = "Gradient Texture", order = 310)]
+public class GradientTexture : ScriptableObject
+{
+    [Delayed]
+    public int width = 64;
+    
+    public List<Gradient> gradients = new List<Gradient>();
+    private Texture2D _texture;
+    
+    private void OnEnable()
+    {
+        if(_texture == null && gradients.Count > 0)
+            Generate();
+    }
+
+    [ContextMenu("Generate")]
+    private void Generate()
+    {
+        // create texture that is width x gradients.Count
+        // for each gradient, draw a line from left to right with the gradient
+        // save to disk
+        
+        if(_texture != null)
+            DestroyImmediate(_texture);
+        _texture = new Texture2D(width, gradients.Count)
+        {
+            name = name
+        };
+        
+        for (int i = 0; i < gradients.Count; i++)
+        {
+            var gradient = gradients[i];
+            for (int x = 0; x < width; x++)
+            {
+                var color = gradient.Evaluate((float)x / width);
+                _texture.SetPixel(x, i, color);
+            }
+        }
+        _texture.Apply();
+        
+        #if UNITY_EDITOR
+        // delayed call to save the icon
+        UnityEditor.EditorApplication.delayCall += SaveIcon;
+        #endif
+    }
+
+    private void OnValidate()
+    {
+        if(gradients.Count > 0)
+            Generate();
+    }
+
+    [ContextMenu("Save")]
+    private void SaveToDisk()
+    {
+#if UNITY_EDITOR
+        // save to disk the texture using the AssetDatabase API
+        var path = UnityEditor.AssetDatabase.GetAssetPath(this);
+        path = path.Replace(".asset", ".png");
+        var bytes = _texture.EncodeToPNG();
+        System.IO.File.WriteAllBytes(path, bytes);
+        UnityEditor.AssetDatabase.SaveAssets();
+        UnityEditor.AssetDatabase.Refresh();
+
+#endif
+    }
+    
+    #if UNITY_EDITOR
+
+    private void SaveIcon()
+    {
+        // use _texture as the icon for this object
+        var path = UnityEditor.AssetDatabase.GetAssetPath(this);
+        
+        // add as sub asset or replace existing
+        var icon = UnityEditor.AssetDatabase.LoadAssetAtPath<Texture2D>(path);
+        
+        if (icon == null)
+        {
+            if(_texture != null)
+            {
+                UnityEditor.AssetDatabase.AddObjectToAsset(_texture, this);
+            }  
+        }
+        else
+        {
+            if(_texture != null)
+            {
+                UnityEditor.EditorUtility.CopySerialized(_texture, icon);
+            }
+        }
+        
+        UnityEditor.AssetDatabase.SaveAssets();
+        UnityEditor.AssetDatabase.Refresh();
+    }
+    
+    #endif
+    
+}

Assets/SharedAssets/Scripts/Editor/GradientTexture.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 6f05a51f4cf024800962869cda1090f7
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: