refactor: fix package structure

Editor/UIParticleMenu.cs

@@ -0,0 +1,46 @@
+using UnityEditor;
+using UnityEngine;
+using UnityEngine.UI;
+
+namespace Coffee.UIExtensions
+{
+    internal class UIParticleMenu
+    {
+        [MenuItem("GameObject/UI/Particle System (Empty)", false, 2018)]
+        private static void AddParticleEmpty(MenuCommand menuCommand)
+        {
+            // Create empty UI element.
+            EditorApplication.ExecuteMenuItem("GameObject/UI/Image");
+            var ui = Selection.activeGameObject;
+            Object.DestroyImmediate(ui.GetComponent<Image>());
+
+            // Add UIParticle.
+            var uiParticle = ui.AddComponent<UIParticle>();
+            uiParticle.name = "UIParticle";
+            uiParticle.scale = 10;
+            uiParticle.rectTransform.sizeDelta = Vector2.zero;
+        }
+
+        [MenuItem("GameObject/UI/Particle System", false, 2019)]
+        private static void AddParticle(MenuCommand menuCommand)
+        {
+            // Create empty UIEffect.
+            AddParticleEmpty(menuCommand);
+            var uiParticle = Selection.activeGameObject.GetComponent<UIParticle>();
+
+            // Create ParticleSystem.
+            EditorApplication.ExecuteMenuItem("GameObject/Effects/Particle System");
+            var ps = Selection.activeGameObject;
+            ps.transform.SetParent(uiParticle.transform, false);
+            ps.transform.localPosition = Vector3.zero;
+
+            // Assign default material (UIAdditive).
+            var renderer = ps.GetComponent<ParticleSystemRenderer>();
+            var path = AssetDatabase.GUIDToAssetPath("9944483a3e009401ba5dcc42f14d5c63");
+            renderer.material = AssetDatabase.LoadAssetAtPath<Material>(path);
+
+            // Refresh particles.
+            uiParticle.RefreshParticles();
+        }
+    }
+}