Fixed up the convex hull 'shadow' creation and deletion after the merge.

Contributes to CURA-1504

cura/ConvexHullDecorator.py

@@ -19,6 +19,19 @@ class ConvexHullDecorator(SceneNodeDecorator):
         Application.getInstance().globalContainerStackChanged.connect(self._onGlobalStackChanged)
         self._onGlobalStackChanged()
 
+    def setNode(self, node):
+        previous_node = self._node
+        if previous_node is not None and node is not previous_node:
+            previous_node.transformationChanged.connect(self._onChanged)
+            previous_node.parentChanged.connect(self._onChanged)
+
+        super().setNode(node)
+
+        self._node.transformationChanged.connect(self._onChanged)
+        self._node.parentChanged.connect(self._onChanged)
+
+        self._onChanged()
+
     ## Force that a new (empty) object is created upon copy.
     def __deepcopy__(self, memo):
         return ConvexHullDecorator()
@@ -67,16 +80,19 @@ class ConvexHullDecorator(SceneNodeDecorator):
         return None
 
     def recomputeConvexHull(self):
-        if self._node is None:
-            return None
+        root = Application.getInstance().getController().getScene().getRoot()
+        if self._node is None or not self.__isDescendant(root, self._node):
+            if self._convex_hull_node:
+                self._convex_hull_node.setParent(None)
+                self._convex_hull_node = None
+            return
 
         convex_hull = self.getConvexHull()
         if self._convex_hull_node:
             if self._convex_hull_node.getHull() == convex_hull:
                 return
             self._convex_hull_node.setParent(None)
-        hull_node = ConvexHullNode.ConvexHullNode(self._node, convex_hull,
-                                                  Application.getInstance().getController().getScene().getRoot())
+        hull_node = ConvexHullNode.ConvexHullNode(self._node, convex_hull, root)
         self._convex_hull_node = hull_node
 
     def _onSettingValueChanged(self, key, property_name):
@@ -205,3 +221,11 @@ class ConvexHullDecorator(SceneNodeDecorator):
             self._global_stack.containersChanged.connect(self._onChanged)
 
             self._onChanged()
+
+    ## Returns true if node is a descendent or the same as the root node.
+    def __isDescendant(self, root, node):
+        if node is None:
+            return False
+        if root is node:
+            return True
+        return self.__isDescendant(root, node.getParent())

cura/ConvexHullNode.py

@@ -1,7 +1,6 @@
 # Copyright (c) 2015 Ultimaker B.V.
 # Cura is released under the terms of the AGPLv3 or higher.
 
-from UM.Application import Application
 from UM.Scene.SceneNode import SceneNode
 from UM.Resources import Resources
 from UM.Math.Color import Color
@@ -31,8 +30,6 @@ class ConvexHullNode(SceneNode):
 
         # The node this mesh is "watching"
         self._node = node
-        self._node.transformationChanged.connect(self._onNodePositionChanged)
-        self._node.parentChanged.connect(self._onNodeParentChanged)
         self._node.decoratorsChanged.connect(self._onNodeDecoratorsChanged)
         self._onNodeDecoratorsChanged(self._node)
 
@@ -84,17 +81,6 @@ class ConvexHullNode(SceneNode):
 
         return True
 
-    def _onNodePositionChanged(self, node):
-        if Application.getInstance().getController().isToolOperationActive():
-            if node.callDecoration("getConvexHull"):
-                self.setParent(None)  # Garbage collection should delete this node after a while.
-
-    def _onNodeParentChanged(self, node):
-        if node.getParent():
-            self.setParent(self._original_parent)
-        else:
-            self.setParent(None)
-
     def _onNodeDecoratorsChanged(self, node):
         self._color = Color(35, 35, 35, 0.5)
 

cura/CuraApplication.py

@@ -741,7 +741,6 @@ class CuraApplication(QtApplication):
 
                     # Add all individual nodes to the selection
                     Selection.add(child)
-                    child.callDecoration("setConvexHull", None)
 
                 op.push()
                 # Note: The group removes itself from the scene once all its children have left it,