Buttons for enabling the 3D preview (unstable)

ResultsDocument.py

@@ -64,9 +64,7 @@ class DocumentObjectToolTipWidget(QtGui.QWidget):
   
     # Tried hiding/detaching the preview to prevent it from disappearing when changing its contents
     #self.preview.viewer.stopAnimating()
-    self.preview.viewer.getViewer().setSceneGraph(obj.ViewObject.RootNode)
-    self.preview.viewer.setCameraOrientation(App.Rotation(1,1,0, 0.2))
-    self.preview.viewer.fitAll()
+    self.preview.showSceneGraph(obj.ViewObject.RootNode)
 
     setParent(self)
     # Let the GUI recompute the side of the description based on its horizontal size.

SafeViewer.py

@@ -1,53 +1,113 @@
 from PySide import QtGui
+import FreeCAD
 
 class SafeViewer(QtGui.QWidget):
   """FreeCAD uses a modified version of QuarterWidget, so the import pivy.quarter one will cause segfaults.
      FreeCAD's FreeCADGui.createViewer() puts the viewer widget inside an MDI window, and detaching it without causing segfaults on exit is tricky.
      This class contains some kludges to extract the viewer as a standalone widget and destroy it safely."""
+  enabled = FreeCAD.ParamGet('User parameter:BaseApp/Preferences/Mod/SearchBar').GetBool('PreviewEnabled', False)
+  instances = []
   def __init__(self, parent = None):
     super(SafeViewer, self).__init__()
-    import FreeCADGui
-    self.viewer = FreeCADGui.createViewer()
-    self.graphicsView = self.viewer.graphicsView()
-    self.oldGraphicsViewParent = self.graphicsView.parent()
-    self.oldGraphicsViewParentParent = self.oldGraphicsViewParent.parent()
-    self.oldGraphicsViewParentParentParent = self.oldGraphicsViewParentParent.parent()
+    SafeViewer.instances.append(self)
+    self.init_parent = parent
+    self.instance_enabled = False # Has this specific instance been enabled?
+    if SafeViewer.enabled:
+      self.displaying_warning = False
+      self.enable()
+    else:
+      import FreeCADGui
+      from PySide import QtCore
+      self.displaying_warning = True
+      self.lbl_warning = QtGui.QTextEdit()
+      self.lbl_warning.setReadOnly(True)
+      self.lbl_warning.setAlignment(QtCore.Qt.AlignTop)
+      self.lbl_warning.setText("Warning: the 3D preview has some stability issues. It can cause FreeCAD to crash (usually when quitting the application) and could in theory cause data loss, inside and outside of FreeCAD.")
+      self.btn_enable_for_this_session = QtGui.QPushButton('Enable 3D preview for this session')
+      self.btn_enable_for_this_session.clicked.connect(self.enable_for_this_session)
+      self.btn_enable_for_future_sessions = QtGui.QPushButton('Enable 3D preview for future sessions')
+      self.btn_enable_for_future_sessions.clicked.connect(self.enable_for_future_sessions)
+      self.setLayout(QtGui.QVBoxLayout())
+      self.layout().addWidget(self.lbl_warning)
+      self.layout().addWidget(self.btn_enable_for_this_session)
+      self.layout().addWidget(self.btn_enable_for_future_sessions)
+  
+  def enable_for_this_session(self):
+    if not SafeViewer.enabled:
+      for instance in SafeViewer.instances:
+        instance.enable()
 
-    # Avoid segfault but still hide the undesired window by moving it to a new hidden MDI area.
-    self.hiddenQMDIArea = QtGui.QMdiArea()
-    self.hiddenQMDIArea.addSubWindow(self.oldGraphicsViewParentParentParent)
+  def enable_for_future_sessions(self):
+    if not SafeViewer.enabled:
+      # Store in prefs
+      FreeCAD.ParamGet('User parameter:BaseApp/Preferences/Mod/SearchBar').SetBool('PreviewEnabled', True)
+      # Then enable as usual
+      self.enable_for_this_session()
 
-    self.private_widget = self.oldGraphicsViewParent
-    self.private_widget.setParent(parent)
+  def enable(self):
+    if not self.instance_enabled:
+      import FreeCADGui
+      # TODO: use a mutex wrapping the entire method, if possible
+      SafeViewer.enabled = True
+      self.instance_enabled = True # Has this specific instance been enabled?
 
-    self.setLayout(QtGui.QVBoxLayout())
-    self.layout().addWidget(self.private_widget)
-    self.layout().setContentsMargins(0,0,0,0)
+      if (self.displaying_warning):
+        self.layout().removeWidget(self.lbl_warning)
+        self.layout().removeWidget(self.btn_enable_for_this_session)
+        self.layout().removeWidget(self.btn_enable_for_future_sessions)
 
-    def fin(slf):
-      slf.finalizer()
+      self.viewer = FreeCADGui.createViewer()
+      self.graphicsView = self.viewer.graphicsView()
+      self.oldGraphicsViewParent = self.graphicsView.parent()
+      self.oldGraphicsViewParentParent = self.oldGraphicsViewParent.parent()
+      self.oldGraphicsViewParentParentParent = self.oldGraphicsViewParentParent.parent()
 
-    import weakref
-    weakref.finalize(self, fin, self)
+      # Avoid segfault but still hide the undesired window by moving it to a new hidden MDI area.
+      self.hiddenQMDIArea = QtGui.QMdiArea()
+      self.hiddenQMDIArea.addSubWindow(self.oldGraphicsViewParentParentParent)
 
-    self.destroyed.connect(self.finalizer)
+      self.private_widget = self.oldGraphicsViewParent
+      self.private_widget.setParent(self.init_parent)
+
+      self.setLayout(QtGui.QVBoxLayout())
+      self.layout().addWidget(self.private_widget)
+      self.layout().setContentsMargins(0,0,0,0)
+
+      def fin(slf):
+        slf.finalizer()
+
+      import weakref
+      weakref.finalize(self, fin, self)
+
+      self.destroyed.connect(self.finalizer)
 
   def finalizer(self):
     # Cleanup in an order that doesn't cause a segfault:
-    self.private_widget.setParent(self.oldGraphicsViewParentParent)
-    self.oldGraphicsViewParentParentParent.close()
-    self.oldGraphicsViewParentParentParent = None
-    self.oldGraphicsViewParentParent = None
-    self.oldGraphicsViewParent = None
-    self.graphicsView = None
-    self.viewer = None
-    #self.parent = None
-    self.hiddenQMDIArea = None
+    if SafeViewer.enabled:
+      self.private_widget.setParent(self.oldGraphicsViewParentParent)
+      self.oldGraphicsViewParentParentParent.close()
+      self.oldGraphicsViewParentParentParent = None
+      self.oldGraphicsViewParentParent = None
+      self.oldGraphicsViewParent = None
+      self.graphicsView = None
+      self.viewer = None
+      #self.parent = None
+      self.init_parent = None
+      self.hiddenQMDIArea = None
+
+  def showSceneGraph(self, g):
+    import FreeCAD as App
+    if SafeViewer.enabled:
+      self.viewer.getViewer().setSceneGraph(g)
+      self.viewer.setCameraOrientation(App.Rotation(1,1,0, 0.2))
+      self.viewer.fitAll()
 
 """
 # Example use:
 from PySide import QtGui
 import pivy
+from SafeViewer import SafeViewer
+sv = SafeViewer()
 def mk(v):
   w = QtGui.QMainWindow()
   oldFocus = QtGui.QApplication.focusWidget()
@@ -66,6 +126,5 @@ def mk(v):
   sv.viewer.getViewer().setSceneGraph(myCustomNode)
   sv.viewer.fitAll()
   return w
-sv = SafeViewer()
 ww=mk(sv)
 """