Add function typing

This causes MyPy to discover errors in this file.

Contributes to issue CURA-5330.

cura/Scene/CuraSceneNode.py

@@ -1,39 +1,42 @@
 # Copyright (c) 2018 Ultimaker B.V.
 # Cura is released under the terms of the LGPLv3 or higher.
+
 from copy import deepcopy
-from typing import List
+from typing import Dict, List, Optional
 
 from UM.Application import Application
 from UM.Math.AxisAlignedBox import AxisAlignedBox
+from UM.Math.Polygon import Polygon #For typing.
 from UM.Scene.SceneNode import SceneNode
 
-from cura.Settings.SettingOverrideDecorator import SettingOverrideDecorator
-
+from cura.CuraApplication import CuraApplication #To get the build plate.
+from cura.Settings.ExtruderStack import ExtruderStack #For typing.
+from cura.Settings.SettingOverrideDecorator import SettingOverrideDecorator #For per-object settings.
 
 ##  Scene nodes that are models are only seen when selecting the corresponding build plate
 #   Note that many other nodes can just be UM SceneNode objects.
 class CuraSceneNode(SceneNode):
-    def __init__(self, *args, **kwargs):
-        super().__init__(*args, **kwargs)
-        if "no_setting_override" not in kwargs:
-            self.addDecorator(SettingOverrideDecorator())  # now we always have a getActiveExtruderPosition, unless explicitly disabled
+    def __init__(self, parent: Optional["SceneNode"] = None, visible: bool = True, name: str = "", no_setting_override: bool = False) -> None:
+        super().__init__(parent = parent, visible = visible, name = name)
+        if not no_setting_override:
+            self.addDecorator(SettingOverrideDecorator())
         self._outside_buildarea = False
 
-    def setOutsideBuildArea(self, new_value):
+    def setOutsideBuildArea(self, new_value: bool) -> None:
         self._outside_buildarea = new_value
 
-    def isOutsideBuildArea(self):
+    def isOutsideBuildArea(self) -> bool:
         return self._outside_buildarea or self.callDecoration("getBuildPlateNumber") < 0
 
-    def isVisible(self):
-        return super().isVisible() and self.callDecoration("getBuildPlateNumber") == Application.getInstance().getMultiBuildPlateModel().activeBuildPlate
+    def isVisible(self) -> bool:
+        return super().isVisible() and self.callDecoration("getBuildPlateNumber") == CuraApplication.getInstance().getMultiBuildPlateModel().activeBuildPlate
 
     def isSelectable(self) -> bool:
-        return super().isSelectable() and self.callDecoration("getBuildPlateNumber") == Application.getInstance().getMultiBuildPlateModel().activeBuildPlate
+        return super().isSelectable() and self.callDecoration("getBuildPlateNumber") == CuraApplication.getInstance().getMultiBuildPlateModel().activeBuildPlate
 
     ##  Get the extruder used to print this node. If there is no active node, then the extruder in position zero is returned
     #   TODO The best way to do it is by adding the setActiveExtruder decorator to every node when is loaded
-    def getPrintingExtruder(self):
+    def getPrintingExtruder(self) -> Optional[ExtruderStack]:
         global_container_stack = Application.getInstance().getGlobalContainerStack()
         per_mesh_stack = self.callDecoration("getStack")
         extruders = list(global_container_stack.extruders.values())
@@ -79,7 +82,7 @@ class CuraSceneNode(SceneNode):
         ]
 
     ##  Return if the provided bbox collides with the bbox of this scene node
-    def collidesWithBbox(self, check_bbox):
+    def collidesWithBbox(self, check_bbox: AxisAlignedBox) -> bool:
         bbox = self.getBoundingBox()
 
         # Mark the node as outside the build volume if the bounding box test fails.
@@ -89,7 +92,7 @@ class CuraSceneNode(SceneNode):
         return False
 
     ##  Return if any area collides with the convex hull of this scene node
-    def collidesWithArea(self, areas):
+    def collidesWithArea(self, areas: List[Polygon]) -> bool:
         convex_hull = self.callDecoration("getConvexHull")
         if convex_hull:
             if not convex_hull.isValid():
@@ -104,8 +107,7 @@ class CuraSceneNode(SceneNode):
         return False
 
     ##  Override of SceneNode._calculateAABB to exclude non-printing-meshes from bounding box
-    def _calculateAABB(self):
-        aabb = None
+    def _calculateAABB(self) -> None:
         if self._mesh_data:
             aabb = self._mesh_data.getExtents(self.getWorldTransformation())
         else:  # If there is no mesh_data, use a boundingbox that encompasses the local (0,0,0)
@@ -123,7 +125,7 @@ class CuraSceneNode(SceneNode):
         self._aabb = aabb
 
     ##  Taken from SceneNode, but replaced SceneNode with CuraSceneNode
-    def __deepcopy__(self, memo):
+    def __deepcopy__(self, memo: Dict[int, object]) -> "CuraSceneNode":
         copy = CuraSceneNode(no_setting_override = True)  # Setting override will be added later
         copy.setTransformation(self.getLocalTransformation())
         copy.setMeshData(self._mesh_data)