Add optional empty placeholder for CuraView

CURA-6469

cura/CuraView.py

@@ -3,8 +3,11 @@
 
 from PyQt5.QtCore import pyqtProperty, QUrl
 
+from UM.Resources import Resources
 from UM.View.View import View
 
+from cura.CuraApplication import CuraApplication
+
 
 # Since Cura has a few pre-defined "space claims" for the locations of certain components, we've provided some structure
 # to indicate this.
@@ -12,13 +15,20 @@ from UM.View.View import View
 #   the stageMenuComponent returns an item that should be used somehwere in the stage menu. It's up to the active stage
 #   to actually do something with this.
 class CuraView(View):
-    def __init__(self, parent = None) -> None:
+    def __init__(self, parent = None, use_empty_menu_placeholder: bool = False) -> None:
         super().__init__(parent)
 
+        self._empty_menu_placeholder_url = QUrl(Resources.getPath(CuraApplication.ResourceTypes.QmlFiles,
+                                                                  "EmptyViewMenuComponent.qml"))
+        self._use_empty_menu_placeholder = use_empty_menu_placeholder
+
     @pyqtProperty(QUrl, constant = True)
     def mainComponent(self) -> QUrl:
         return self.getDisplayComponent("main")
 
     @pyqtProperty(QUrl, constant = True)
     def stageMenuComponent(self) -> QUrl:
-        return self.getDisplayComponent("menu")
+        url = self.getDisplayComponent("menu")
+        if not url.toString() and self._use_empty_menu_placeholder:
+            url = self._empty_menu_placeholder_url
+        return url

plugins/XRayView/XRayView.py

@@ -10,21 +10,21 @@ from UM.Math.Color import Color
 from UM.PluginRegistry import PluginRegistry
 from UM.Platform import Platform
 from UM.Event import Event
-from UM.View.View import View
 from UM.Scene.Iterator.BreadthFirstIterator import BreadthFirstIterator
 
 from UM.View.RenderBatch import RenderBatch
 from UM.View.GL.OpenGL import OpenGL
 
 from cura.CuraApplication import CuraApplication
+from cura.CuraView import CuraView
 from cura.Scene.ConvexHullNode import ConvexHullNode
 
 from . import XRayPass
 
 ## View used to display a see-through version of objects with errors highlighted.
-class XRayView(View):
+class XRayView(CuraView):
     def __init__(self):
-        super().__init__()
+        super().__init__(parent = None, use_empty_menu_placeholder = True)
 
         self._xray_shader = None
         self._xray_pass = None

resources/qml/EmptyViewMenuComponent.qml

@@ -0,0 +1,9 @@
+// Copyright (c) 2019 Ultimaker B.V.
+// Cura is released under the terms of the LGPLv3 or higher.
+
+import QtQuick 2.10
+import QtQuick.Controls 2.3
+
+
+// Empty placeholder
+Item { }