HierarchyView : Add sceneListing() method

This is intended to give clients access to the `columnContextMenuSignal()` to customise the context menu. Currently it returns a bare PathListingWidget which gives clients more privilege than is ideal (we don't want them to change the path!), but in future should return a more specialised SceneListing widget. That won't appear till Gaffer 1.5 though, and we want to allow the menu to be customised in 1.4. So for now we content ourselves with a little warning that folks shouldn't get addicted to anything other than the context menu signal.

Changes.md

@@ -18,6 +18,7 @@ API
 ---
 
 - PathListingWidget : Added `columnContextMenuSignal()`, allowing multiple clients to collaborate on the creation of a column-specific context menu.
+- HierarchyView : Added `sceneListing()` method, to allow the context menu to be customised.
 
 Documentation
 -------------

python/GafferSceneUI/HierarchyView.py

@@ -88,7 +88,7 @@ def __init__( self, scriptNode, **kw ) :
 			self.__selectionChangedConnection = self.__pathListing.selectionChangedSignal().connect( Gaffer.WeakMethod( self.__selectionChanged ), scoped = False )
 			self.__expansionChangedConnection = self.__pathListing.expansionChangedSignal().connect( Gaffer.WeakMethod( self.__expansionChanged ), scoped = False )
 
-			self.__pathListing.contextMenuSignal().connect( Gaffer.WeakMethod( self.__contextMenuSignal ), scoped = False )
+			self.__pathListing.columnContextMenuSignal().connect( Gaffer.WeakMethod( self.__columnContextMenuSignal ), scoped = False )
 			self.keyPressSignal().connect( Gaffer.WeakMethod( self.__keyPressSignal ), scoped = False )
 
 		self.__plug = None
@@ -100,6 +100,17 @@ def scene( self ) :
 
 		return self.__plug
 
+	## Returns the widget used for showing the main scene listing, with the
+	# intention that clients can add custom context menu items via
+	# `sceneListing.columnContextMenuSignal()`.
+	#
+	# > Caution : This currently returns a PathListingWidget, but in future
+	# > will probably return a more specialised widget with fewer privileges.
+	# > Please limit usage to `columnContextMenuSignal()`.
+	def sceneListing( self ) :
+
+		return self.__pathListing
+
 	def __repr__( self ) :
 
 		return "GafferSceneUI.HierarchyView( scriptNode )"
@@ -209,11 +220,9 @@ def __keyPressSignal( self, widget, event ) :
 
 		return False
 
-	def __contextMenuSignal( self, widget ) :
-
-		menuDefinition = IECore.MenuDefinition()
+	def __columnContextMenuSignal( self, column, pathListing, menuDefinition ) :
 
-		selection = self.__pathListing.getSelection()
+		selection = pathListing.getSelection()
 		menuDefinition.append(
 			"Copy Path%s" % ( "" if selection.size() == 1 else "s" ),
 			{
@@ -231,11 +240,6 @@ def __contextMenuSignal( self, widget ) :
 			}
 		)
 
-		self.__contextMenu = GafferUI.Menu( menuDefinition )
-		self.__contextMenu.popup( widget )
-
-		return True
-
 	def __copySelectedPaths( self, *unused ) :
 
 		if self.__plug is None :