Draft: Don't snap to ImagePlanes

src/Mod/Draft/draftguitools/gui_snapper.py

@@ -57,6 +57,7 @@
 __author__ = "Yorik van Havre"
 __url__ = "https://www.freecadweb.org"
 
+UNSNAPPABLES = ('Image::ImagePlane',)
 
 class Snapper:
     """Classes to manage snapping in Draft and Arch.
@@ -125,7 +126,7 @@ def __init__(self):
 
         # snap keys, it's important that they are in this order for
         # saving in preferences and for properly restoring the toolbar
-        self.snaps = ['Lock',           # 0 
+        self.snaps = ['Lock',           # 0
                       'Near',           # 1 former "passive" snap
                       'Extension',      # 2
                       'Parallel',       # 3
@@ -311,6 +312,8 @@ def snap(self, screenpos,
             point, eline = self.snapToExtensions(point, lastpoint,
                                                  constrain, eline)
 
+        # Check if we have an object under the cursor and try to
+        # snap to it
         _view = Draft.get3DView()
         objectsUnderCursor = _view.getObjectsInfo((screenpos[0], screenpos[1]))
         if objectsUnderCursor:
@@ -319,8 +322,10 @@ def snap(self, screenpos,
             self.snapInfo = objectsUnderCursor[self.snapObjectIndex]
 
         if self.snapInfo and "Component" in self.snapInfo:
-            return self.snapToObject(lastpoint, active, constrain,
+            osnap = self.snapToObject(lastpoint, active, constrain,
                                      eline, point, oldActive)
+            if osnap:
+                return osnap
 
         # Nothing has been snapped.
         # Check for grid snap and ext crossings
@@ -352,6 +357,7 @@ def cycleSnapObject(self):
     def snapToObject(self, lastpoint, active, constrain,
                      eline, point, oldActive):
         """Snap to an object."""
+
         parent = self.snapInfo.get('ParentObject', None)
         if parent:
             subname = self.snapInfo['SubName']
@@ -368,6 +374,9 @@ def snapToObject(self, lastpoint, active, constrain,
         snaps = []
         self.lastSnappedObject = obj
 
+        if obj and (Draft.getType(obj) in UNSNAPPABLES):
+            return []
+
         if hasattr(obj.ViewObject, "Selectable"):
             if not obj.ViewObject.Selectable:
                 self.spoint = self.cstr(lastpoint, constrain, point)
@@ -609,9 +618,9 @@ def snapToExtensions(self, point, last, constrain, eline):
                         self.setCursor(tsnap[1])
                         return tsnap[2], eline
 
-        for o in (self.lastObj[1], self.lastObj[0]): 
-            if o and (self.isEnabled('Extension') 
-                      or self.isEnabled('Parallel')):            
+        for o in (self.lastObj[1], self.lastObj[0]):
+            if o and (self.isEnabled('Extension')
+                      or self.isEnabled('Parallel')):
                 ob = App.ActiveDocument.getObject(o)
                 if not ob:
                     continue
@@ -1480,8 +1489,8 @@ def init_draft_snap_buttons(self, commands, context, button_suffix):
         Parameters:
         commands        Snap command list,
                         use: get_draft_snap_commands():
-        context         The toolbar or action group the buttons have 
-                        to be added to    
+        context         The toolbar or action group the buttons have
+                        to be added to
         button_suffix   The suffix that have to be applied to the command name
                         to define the button name
         """
@@ -1492,7 +1501,7 @@ def init_draft_snap_buttons(self, commands, context, button_suffix):
                 gb = self.init_grid_button(self.toolbar)
                 context.addAction(gb)
                 QtCore.QObject.connect(gb, QtCore.SIGNAL("triggered()"),
-                                    lambda f=Gui.doCommand, 
+                                    lambda f=Gui.doCommand,
                                     arg='Gui.runCommand("Draft_ToggleGrid")':f(arg))
                 continue
             # setup toolbar buttons
@@ -1508,7 +1517,7 @@ def init_draft_snap_buttons(self, commands, context, button_suffix):
             context.addAction(b)
             QtCore.QObject.connect(b,
                                    QtCore.SIGNAL("triggered()"),
-                                   lambda f=Gui.doCommand, 
+                                   lambda f=Gui.doCommand,
                                    arg=command:f(arg))
 
         for b in context.actions():
@@ -1520,7 +1529,7 @@ def init_grid_button(self, context):
         """Add grid button to the given toolbar"""
         b = QtGui.QAction(context)
         b.setIcon(QtGui.QIcon.fromTheme("Draft", QtGui.QIcon(":/icons/"
-                                                         "Draft_Grid.svg")))        
+                                                         "Draft_Grid.svg")))
         b.setText(QtCore.QCoreApplication.translate("Draft_Snap", "Toggles Grid On/Off"))
         b.setToolTip(QtCore.QCoreApplication.translate("Draft_Snap", "Toggle Draft Grid"))
         b.setObjectName("Grid_Button")
@@ -1703,7 +1712,7 @@ def setTrackers(self):
                 self.trackers[8].append(self.extLine2)
                 self.trackers[9].append(self.holdTracker)
             self.activeview = v
-            
+
         if self.grid and (not self.forceGridOff):
             self.grid.set()