try migrate first operator

bbp_ng/__init__.py

@@ -15,7 +15,7 @@ bl_info = {
 
 # import core lib
 import bpy
-import typing
+import typing, collections
 
 # reload if needed
 if "bpy" in locals():
@@ -23,13 +23,71 @@ if "bpy" in locals():
 
 #endregion
 
+from . import OP_UV_flatten_uv
+
+#region Menu
+
+# ===== Menu Defines =====
+
+class BBP_MT_View3DMenu(bpy.types.Menu):
+    """Ballance 3D operators"""
+    bl_idname = "BBP_MT_View3DMenu"
+    bl_label = "Ballance"
+
+    def draw(self, context):
+        layout = self.layout
+
+        layout.operator(OP_UV_flatten_uv.BBP_OT_flatten_uv.bl_idname)
+
+# ===== Menu Drawer =====
+
+MenuDrawer_t = typing.Callable[[typing.Any, typing.Any], None]
+
+def menu_drawer_view3d(self, context):
+    layout = self.layout
+    layout.menu(BBP_MT_View3DMenu.bl_idname)
+
+#endregion
+
 #region Register and Unregister.
 
+g_Classes: tuple[typing.Any, ...] = (
+    OP_UV_flatten_uv.BBP_OT_flatten_uv,
+    BBP_MT_View3DMenu,
+)
+
+class MenuEntry():
+    mContainerMenu: bpy.types.Menu
+    mIsAppend: bool
+    mMenuDrawer: MenuDrawer_t
+    def __init__(self, cont: bpy.types.Menu, is_append: bool, menu_func: MenuDrawer_t):
+        self.mContainerMenu = cont
+        self.mIsAppend = is_append
+        self.mMenuDrawer = menu_func
+g_Menus: tuple[MenuEntry, ...] = (
+     MenuEntry(bpy.types.VIEW3D_MT_editor_menus, False, menu_drawer_view3d),
+)
+
 def register() -> None:
-    pass
+    # register all classes
+    for cls in g_Classes:
+        bpy.utils.register_class(cls)
+
+    # add menu drawer
+    for entry in g_Menus:
+        if entry.mIsAppend:
+            entry.mContainerMenu.append(entry.mMenuDrawer)
+        else:
+            entry.mContainerMenu.prepend(entry.mMenuDrawer)
 
 def unregister() -> None:
-    pass
+    # remove menu drawer
+    for entry in g_Menus:
+        entry.mContainerMenu.remove(entry.mMenuDrawer)
+
+    # unregister classes
+    for cls in g_Classes:
+        bpy.utils.unregister_class(cls)
 
 if __name__ == "__main__":
     register()