Cura/cura/Operations/SetParentOperation.py
2020-05-29 14:30:33 +02:00

72 lines
3.2 KiB
Python

# Copyright (c) 2016 Ultimaker B.V.
# Uranium is released under the terms of the LGPLv3 or higher.
from typing import Optional
from UM.Scene.SceneNode import SceneNode
from UM.Operations import Operation
class SetParentOperation(Operation.Operation):
"""An operation that parents a scene node to another scene node."""
def __init__(self, node: SceneNode, parent_node: Optional[SceneNode]) -> None:
"""Initialises this SetParentOperation.
:param node: The node which will be reparented.
:param parent_node: The node which will be the parent.
"""
super().__init__()
self._node = node
self._parent = parent_node
self._old_parent = node.getParent() # To restore the previous parent in case of an undo.
def undo(self) -> None:
"""Undoes the set-parent operation, restoring the old parent."""
self._set_parent(self._old_parent)
def redo(self) -> None:
"""Re-applies the set-parent operation."""
self._set_parent(self._parent)
def _set_parent(self, new_parent: Optional[SceneNode]) -> None:
"""Sets the parent of the node while applying transformations to the world-transform of the node stays the same.
:param new_parent: The new parent. Note: this argument can be None, which would hide the node from the scene.
"""
if new_parent:
current_parent = self._node.getParent()
if current_parent:
# Special casing for groups that have been removed.
# In that case we want to put them back where they belong before checking the depth difference.
# If we don't, we always get 0.
old_parent = new_parent.callDecoration("getOldParent")
if old_parent:
new_parent.callDecoration("getNode").setParent(old_parent)
# Based on the depth difference, we need to do something different.
depth_difference = current_parent.getDepth() - new_parent.getDepth()
child_transformation = self._node.getLocalTransformation()
if depth_difference > 0:
parent_transformation = current_parent.getLocalTransformation()
# A node in the chain was removed, so we need to squash the parent info into all the nodes, so positions remain the same.
self._node.setTransformation(parent_transformation.multiply(child_transformation))
else:
# A node is inserted into the chain, so use the inverse of the parent to set the transformation of it's children.
parent_transformation = new_parent.getLocalTransformation()
result = parent_transformation.getInverse().multiply(child_transformation, copy = True)
self._node.setTransformation(result)
self._node.setParent(new_parent)
def __repr__(self) -> str:
"""Returns a programmer-readable representation of this operation.
:return: A programmer-readable representation of this operation.
"""
return "SetParentOperation(node = {0}, parent_node={1})".format(self._node, self._parent)