From a00dddffe75f046f8f77c2606f8bcfd6448ed43f Mon Sep 17 00:00:00 2001
From: Bernd Hahnebach <bernd@bimstatik.org>
Date: Tue, 3 Mar 2020 21:04:31 +0100
Subject: [PATCH] FEM: use python base constraint class, shell thickness

---
 .../_ViewProviderFemElementGeometry2D.py      | 67 +++----------------
 .../Fem/femobjects/_FemElementGeometry2D.py   | 14 ++--
 2 files changed, 17 insertions(+), 64 deletions(-)

diff --git a/src/Mod/Fem/femguiobjects/_ViewProviderFemElementGeometry2D.py b/src/Mod/Fem/femguiobjects/_ViewProviderFemElementGeometry2D.py
index e84ab93fcb..d289ded278 100644
--- a/src/Mod/Fem/femguiobjects/_ViewProviderFemElementGeometry2D.py
+++ b/src/Mod/Fem/femguiobjects/_ViewProviderFemElementGeometry2D.py
@@ -30,76 +30,27 @@ __url__ = "http://www.freecadweb.org"
 
 import FreeCAD
 import FreeCADGui
-import FemGui  # needed to display the icons in TreeView
+
+from . import ViewProviderFemConstraint
 
 # for the panel
 from PySide import QtCore
 from . import FemSelectionWidgets
 
-False if FemGui.__name__ else True  # flake8, dummy FemGui usage
 
-
-class _ViewProviderFemElementGeometry2D:
+class _ViewProviderFemElementGeometry2D(ViewProviderFemConstraint.ViewProxy):
     "A View Provider for the FemElementGeometry2D object"
 
-    def __init__(self, vobj):
-        vobj.Proxy = self
-
     def getIcon(self):
         return ":/icons/fem-element-geometry-2d.svg"
 
-    def attach(self, vobj):
-        from pivy import coin
-        self.ViewObject = vobj
-        self.Object = vobj.Object
-        self.standard = coin.SoGroup()
-        vobj.addDisplayMode(self.standard, "Default")
-
-    def getDisplayModes(self, obj):
-        return ["Default"]
-
-    def getDefaultDisplayMode(self):
-        return "Default"
-
-    def updateData(self, obj, prop):
-        return
-
-    def onChanged(self, vobj, prop):
-        return
-
     def setEdit(self, vobj, mode=0):
-        # hide all meshes
-        for o in FreeCAD.ActiveDocument.Objects:
-            if o.isDerivedFrom("Fem::FemMeshObject"):
-                o.ViewObject.hide()
-        # show task panel
-        taskd = _TaskPanelFemElementGeometry2D(self.Object)
-        taskd.obj = vobj.Object
-        FreeCADGui.Control.showDialog(taskd)
-        return True
-
-    def unsetEdit(self, vobj, mode=0):
-        FreeCADGui.Control.closeDialog()
-        return True
-
-    def doubleClicked(self, vobj):
-        guidoc = FreeCADGui.getDocument(vobj.Object.Document)
-        # check if another VP is in edit mode
-        # https://forum.freecadweb.org/viewtopic.php?t=13077#p104702
-        if not guidoc.getInEdit():
-            guidoc.setEdit(vobj.Object.Name)
-        else:
-            from PySide.QtGui import QMessageBox
-            message = "Active Task Dialog found! Please close this one before opening  a new one!"
-            QMessageBox.critical(None, "Error in tree view", message)
-            FreeCAD.Console.PrintError(message + "\n")
-        return True
-
-    def __getstate__(self):
-        return None
-
-    def __setstate__(self, state):
-        return None
+        ViewProviderFemConstraint.ViewProxy.setEdit(
+            self,
+            vobj,
+            mode,
+            _TaskPanelFemElementGeometry2D
+        )
 
 
 class _TaskPanelFemElementGeometry2D:
diff --git a/src/Mod/Fem/femobjects/_FemElementGeometry2D.py b/src/Mod/Fem/femobjects/_FemElementGeometry2D.py
index 70edbbaf8b..ee677cb60d 100644
--- a/src/Mod/Fem/femobjects/_FemElementGeometry2D.py
+++ b/src/Mod/Fem/femobjects/_FemElementGeometry2D.py
@@ -27,10 +27,17 @@ __url__ = "https://www.freecadweb.org"
 #  \ingroup FEM
 #  \brief FreeCAD FEM element geometry 2D object
 
+from . import FemConstraint
 
-class _FemElementGeometry2D:
+
+class _FemElementGeometry2D(FemConstraint.Proxy):
     "The FemElementGeometry2D object"
+
+    Type = "Fem::ElementGeometry2D"
+
     def __init__(self, obj):
+        super(_FemElementGeometry2D, self).__init__(obj)
+
         obj.addProperty(
             "App::PropertyLength",
             "Thickness",
@@ -43,8 +50,3 @@ class _FemElementGeometry2D:
             "ShellThickness",
             "List of shell thickness shapes"
         )
-        obj.Proxy = self
-        self.Type = "Fem::ElementGeometry2D"
-
-    def execute(self, obj):
-        return