Cura/cura/ObjectManager.py

from UM.Logger import Logger
from PyQt5.QtCore import pyqtSignal, pyqtProperty, pyqtSlot
from UM.Application import Application
from UM.Qt.ListModel import ListModel
from UM.Scene.Iterator.DepthFirstIterator import DepthFirstIterator
from UM.Scene.SceneNode import SceneNode
from UM.Scene.Selection import Selection
from PyQt5.QtCore import Qt
from PyQt5.QtWidgets import QApplication


class ObjectManager(ListModel):
    def __init__(self):
        super().__init__()
        self._last_selected_index = 0
        Application.getInstance().getController().getScene().sceneChanged.connect(self._update)

    def _update(self, *args):
        nodes = []
        for node in DepthFirstIterator(Application.getInstance().getController().getScene().getRoot()):
            if type(node) is not SceneNode or (not node.getMeshData() and not node.callDecoration("getLayerData")):
                continue
            nodes.append({
                "name": node.getName(),
                "isSelected": Selection.isSelected(node),
                "buildPlateNumber": node.callDecoration("getBuildPlateNumber"),
                "node": node
            })
        nodes = sorted(nodes, key=lambda n: n["name"])
        self.setItems(nodes)

        self.itemsChanged.emit()

    ##  Either select or deselect an item
    @pyqtSlot(int)
    def changeSelection(self, index):
        modifiers = QApplication.keyboardModifiers()
        ctrl_is_active = modifiers & Qt.ControlModifier
        shift_is_active = modifiers & Qt.ShiftModifier

        if ctrl_is_active:
            item = self.getItem(index)
            node = item["node"]
            if Selection.isSelected(node):
                Selection.remove(node)
            else:
                Selection.add(node)
        elif shift_is_active:
            polarity = 1 if index + 1 > self._last_selected_index else -1
            for i in range(self._last_selected_index, index + polarity, polarity):
                item = self.getItem(i)
                node = item["node"]
                Selection.add(node)
        else:
            # Single select
            item = self.getItem(index)
            node = item["node"]
            Selection.clear()
            Selection.add(node)
            build_plate_number = node.callDecoration("getBuildPlateNumber")
            if build_plate_number is not None and build_plate_number != -1:
                Application.getInstance().setActiveBuildPlate(build_plate_number)

        self._last_selected_index = index

    @staticmethod
    def createObjectManager():
        return ObjectManager()