Freestyle Python API improvements - part 8.

* Proper handling of keyword arguments was implemented in Operators and ContextFunctions,
as well as in methods of Interface0D, Interface1D, Iterator, their subclasses, Noise and
IntegrationType.

* Operators' methods and functions in the ContextFunctions module were renamed from
CamelCase to lower cases + underscores.  Style modules were updated accordingly.

* Additional code clean-up was also made.

43 files changed, 79 insertions, 76 deletions

diff --git a/release/scripts/freestyle/style_modules/ChainingIterators.py b/release/scripts/freestyle/style_modules/ChainingIterators.py
index 97654e0bf88..3ed67383115 100644
--- a/release/scripts/freestyle/style_modules/ChainingIterators.py
+++ b/release/scripts/freestyle/style_modules/ChainingIterators.py
@@ -26,6 +26,7 @@
 #############################################################################
 
 from freestyle_init import *
+from Freestyle import ContextFunctions as CF
 
 ## the natural chaining iterator
 ## It follows the edges of same nature following the topology of
@@ -155,7 +156,7 @@ class pyExternalContourChainingIterator(ChainingIterator):
 		while not it.is_end:
 			ve = it.object
 			if self._isExternalContour(ve):
-				if ve.time_stamp == GetTimeStampCF():
+				if ve.time_stamp == CF.get_time_stamp():
 					winner = ve
 			it.increment()
 		
@@ -178,10 +179,10 @@ class pyExternalContourChainingIterator(ChainingIterator):
 class pySketchyChainSilhouetteIterator(ChainingIterator):
 	def __init__(self, nRounds=3,stayInSelection=True):
 		ChainingIterator.__init__(self, stayInSelection, False, None, True)
-		self._timeStamp = GetTimeStampCF()+nRounds
+		self._timeStamp = CF.get_time_stamp()+nRounds
 		self._nRounds = nRounds
 	def init(self):
-		self._timeStamp = GetTimeStampCF()+self._nRounds
+		self._timeStamp = CF.get_time_stamp()+self._nRounds
 	def traverse(self, iter):
 		winner = None
 		it = AdjacencyIterator(iter)
@@ -235,10 +236,10 @@ class pySketchyChainSilhouetteIterator(ChainingIterator):
 class pySketchyChainingIterator(ChainingIterator):
 	def __init__(self, nRounds=3, stayInSelection=True):
 		ChainingIterator.__init__(self, stayInSelection, False, None, True)
-		self._timeStamp = GetTimeStampCF()+nRounds
+		self._timeStamp = CF.get_time_stamp()+nRounds
 		self._nRounds = nRounds
 	def init(self):
-		self._timeStamp = GetTimeStampCF()+self._nRounds
+		self._timeStamp = CF.get_time_stamp()+self._nRounds
 	def traverse(self, iter):
 		winner = None
 		it = AdjacencyIterator(iter)
@@ -309,7 +310,7 @@ class pyFillOcclusionsRelativeChainingIterator(ChainingIterator):
 					break
 		if winner is not None:
 			# check whether this edge was part of the selection
-			if winner.time_stamp != GetTimeStampCF():
+			if winner.time_stamp != CF.get_time_stamp():
 				#print("---", winner.id.first, winner.id.second)
 				# if not, let's check whether it's short enough with
 				# respect to the chain made without staying in the selection
@@ -348,7 +349,7 @@ class pyFillOcclusionsRelativeChainingIterator(ChainingIterator):
 				_cit.current_edge = winner
 				_cit.orientation = winnerOrientation
 				_cit.init()
-				while _cit.is_end == 0 and _cit.object.time_stamp != GetTimeStampCF():
+				while _cit.is_end == 0 and _cit.object.time_stamp != CF.get_time_stamp():
 					ve = _cit.object
 					#print("-------- --------", ve.id.first, ve.id.second)
 					connexl = connexl + ve.length_2d
@@ -406,7 +407,7 @@ class pyFillOcclusionsAbsoluteChainingIterator(ChainingIterator):
 					break
 		if winner is not None:
 			# check whether this edge was part of the selection
-			if winner.time_stamp != GetTimeStampCF():
+			if winner.time_stamp != CF.get_time_stamp():
 				#print("---", winner.id.first, winner.id.second)
 				# nw let's compute the length of this connex non selected part:
 				connexl = 0
@@ -415,7 +416,7 @@ class pyFillOcclusionsAbsoluteChainingIterator(ChainingIterator):
 				_cit.current_edge = winner
 				_cit.orientation = winnerOrientation
 				_cit.init()
-				while _cit.is_end == 0 and _cit.object.time_stamp != GetTimeStampCF():
+				while _cit.is_end == 0 and _cit.object.time_stamp != CF.get_time_stamp():
 					ve = _cit.object
 					#print("-------- --------", ve.id.first, ve.id.second)
 					connexl = connexl + ve.length_2d
@@ -479,7 +480,7 @@ class pyFillOcclusionsAbsoluteAndRelativeChainingIterator(ChainingIterator):
 					break
 		if winner is not None:
 			# check whether this edge was part of the selection
-			if winner.time_stamp != GetTimeStampCF():
+			if winner.time_stamp != CF.get_time_stamp():
 				#print("---", winner.id.first, winner.id.second)
 				# if not, let's check whether it's short enough with
 				# respect to the chain made without staying in the selection
@@ -518,7 +519,7 @@ class pyFillOcclusionsAbsoluteAndRelativeChainingIterator(ChainingIterator):
 				_cit.current_edge = winner
 				_cit.orientation = winnerOrientation
 				_cit.init()
-				while _cit.is_end == 0 and _cit.object.time_stamp != GetTimeStampCF():
+				while _cit.is_end == 0 and _cit.object.time_stamp != CF.get_time_stamp():
 					ve = _cit.object
 					#print("-------- --------", ve.id.first, ve.id.second)
 					connexl = connexl + ve.length_2d
diff --git a/release/scripts/freestyle/style_modules/Functions0D.py b/release/scripts/freestyle/style_modules/Functions0D.py
index ffdddaa4a1f..abbf5fe278c 100644
--- a/release/scripts/freestyle/style_modules/Functions0D.py
+++ b/release/scripts/freestyle/style_modules/Functions0D.py
@@ -1,4 +1,5 @@
 from freestyle_init import *
+from Freestyle import ContextFunctions as CF
 
 class CurveMaterialF0D(UnaryFunction0DMaterial):
 	# A replacement of the built-in MaterialF0D for stroke creation.
@@ -55,8 +56,8 @@ class pyViewMapGradientVectorF0D(UnaryFunction0DVec2f):
 		self._step = pow(2,self._l)
 	def __call__(self, iter):
 		p = iter.object.point_2d
-		gx = ReadCompleteViewMapPixelCF(self._l, int(p.x+self._step), int(p.y))- ReadCompleteViewMapPixelCF(self._l, int(p.x), int(p.y))
-		gy = ReadCompleteViewMapPixelCF(self._l, int(p.x), int(p.y+self._step))- ReadCompleteViewMapPixelCF(self._l, int(p.x), int(p.y))
+		gx = CF.read_complete_view_map_pixel(self._l, int(p.x+self._step), int(p.y))- CF.read_complete_view_map_pixel(self._l, int(p.x), int(p.y))
+		gy = CF.read_complete_view_map_pixel(self._l, int(p.x), int(p.y+self._step))- CF.read_complete_view_map_pixel(self._l, int(p.x), int(p.y))
 		return Vector([gx, gy])
 
 class pyViewMapGradientNormF0D(UnaryFunction0DDouble):
@@ -66,8 +67,8 @@ class pyViewMapGradientNormF0D(UnaryFunction0DDouble):
 		self._step = pow(2,self._l)
 	def __call__(self, iter):
 		p = iter.object.point_2d
-		gx = ReadCompleteViewMapPixelCF(self._l, int(p.x+self._step), int(p.y))- ReadCompleteViewMapPixelCF(self._l, int(p.x), int(p.y))
-		gy = ReadCompleteViewMapPixelCF(self._l, int(p.x), int(p.y+self._step))- ReadCompleteViewMapPixelCF(self._l, int(p.x), int(p.y))
+		gx = CF.read_complete_view_map_pixel(self._l, int(p.x+self._step), int(p.y))- CF.read_complete_view_map_pixel(self._l, int(p.x), int(p.y))
+		gy = CF.read_complete_view_map_pixel(self._l, int(p.x), int(p.y+self._step))- CF.read_complete_view_map_pixel(self._l, int(p.x), int(p.y))
 		grad = Vector([gx, gy])
 		return grad.length
 
diff --git a/release/scripts/freestyle/style_modules/anisotropic_diffusion.py b/release/scripts/freestyle/style_modules/anisotropic_diffusion.py
index 44a820a1048..17fb2e738f6 100644
--- a/release/scripts/freestyle/style_modules/anisotropic_diffusion.py
+++ b/release/scripts/freestyle/style_modules/anisotropic_diffusion.py
@@ -36,7 +36,7 @@ nbIter = 30
 upred = AndUP1D(QuantitativeInvisibilityUP1D(0), ExternalContourUP1D())
 Operators.select( upred )
 bpred = TrueBP1D()
-Operators.bidirectionalChain(ChainPredicateIterator(upred, bpred), NotUP1D(upred) )
+Operators.bidirectional_chain(ChainPredicateIterator(upred, bpred), NotUP1D(upred) )
 shaders_list = [
     ConstantThicknessShader(4),
     StrokeTextureShader("smoothAlpha.bmp", Stroke.OPAQUE_MEDIUM, False),
diff --git a/release/scripts/freestyle/style_modules/apriori_and_causal_density.py b/release/scripts/freestyle/style_modules/apriori_and_causal_density.py
index 7cdd4b2fd66..212e2b8479e 100644
--- a/release/scripts/freestyle/style_modules/apriori_and_causal_density.py
+++ b/release/scripts/freestyle/style_modules/apriori_and_causal_density.py
@@ -37,7 +37,7 @@ from shaders import *
 upred = AndUP1D(QuantitativeInvisibilityUP1D(0), pyHighViewMapDensityUP1D(0.3, IntegrationType.LAST))
 Operators.select(upred)
 bpred = TrueBP1D()
-Operators.bidirectionalChain(ChainPredicateIterator(upred, bpred), NotUP1D(QuantitativeInvisibilityUP1D(0)))
+Operators.bidirectional_chain(ChainPredicateIterator(upred, bpred), NotUP1D(QuantitativeInvisibilityUP1D(0)))
 shaders_list = 	[
 		ConstantThicknessShader(2), 
 		ConstantColorShader(0.0, 0.0, 0.0,1)
diff --git a/release/scripts/freestyle/style_modules/apriori_density.py b/release/scripts/freestyle/style_modules/apriori_density.py
index 5ff6c58e77f..31f33354674 100644
--- a/release/scripts/freestyle/style_modules/apriori_density.py
+++ b/release/scripts/freestyle/style_modules/apriori_density.py
@@ -35,7 +35,7 @@ from shaders import *
 Operators.select(AndUP1D(QuantitativeInvisibilityUP1D(0), pyHighViewMapDensityUP1D(0.1,5)))
 bpred = TrueBP1D()
 upred = AndUP1D(QuantitativeInvisibilityUP1D(0), pyHighViewMapDensityUP1D(0.0007,5))
-Operators.bidirectionalChain(ChainPredicateIterator(upred, bpred), NotUP1D(QuantitativeInvisibilityUP1D(0)))
+Operators.bidirectional_chain(ChainPredicateIterator(upred, bpred), NotUP1D(QuantitativeInvisibilityUP1D(0)))
 shaders_list = 	[
 		ConstantThicknessShader(2), 
 		ConstantColorShader(0.0, 0.0, 0.0,1)
diff --git a/release/scripts/freestyle/style_modules/backbone_stretcher.py b/release/scripts/freestyle/style_modules/backbone_stretcher.py
index 8a6b9d71a66..a08d0806c7e 100644
--- a/release/scripts/freestyle/style_modules/backbone_stretcher.py
+++ b/release/scripts/freestyle/style_modules/backbone_stretcher.py
@@ -31,6 +31,6 @@ from PredicatesB1D import *
 from shaders import *
 
 Operators.select(QuantitativeInvisibilityUP1D(0))
-Operators.bidirectionalChain(ChainSilhouetteIterator(), NotUP1D(QuantitativeInvisibilityUP1D(0)))
+Operators.bidirectional_chain(ChainSilhouetteIterator(), NotUP1D(QuantitativeInvisibilityUP1D(0)))
 shaders_list = [TextureAssignerShader(4), ConstantColorShader(0.5, 0.5, 0.5), BackboneStretcherShader(20)]
 Operators.create(TrueUP1D(), shaders_list)
diff --git a/release/scripts/freestyle/style_modules/blueprint_circles.py b/release/scripts/freestyle/style_modules/blueprint_circles.py
index 7f3a7564cfe..5315fd6cebe 100644
--- a/release/scripts/freestyle/style_modules/blueprint_circles.py
+++ b/release/scripts/freestyle/style_modules/blueprint_circles.py
@@ -34,7 +34,7 @@ from shaders import *
 upred = AndUP1D(QuantitativeInvisibilityUP1D(0), ContourUP1D())
 bpred = SameShapeIdBP1D()
 Operators.select(upred)
-Operators.bidirectionalChain(ChainPredicateIterator(upred,bpred), NotUP1D(upred))
+Operators.bidirectional_chain(ChainPredicateIterator(upred,bpred), NotUP1D(upred))
 Operators.select(pyHigherLengthUP1D(200))
 shaders_list = [
 		ConstantThicknessShader(5),
diff --git a/release/scripts/freestyle/style_modules/blueprint_ellipses.py b/release/scripts/freestyle/style_modules/blueprint_ellipses.py
index a5cfe4ec30b..c4c7d1312f0 100644
--- a/release/scripts/freestyle/style_modules/blueprint_ellipses.py
+++ b/release/scripts/freestyle/style_modules/blueprint_ellipses.py
@@ -34,7 +34,7 @@ from shaders import *
 upred = AndUP1D(QuantitativeInvisibilityUP1D(0), ContourUP1D())
 bpred = SameShapeIdBP1D()
 Operators.select(upred)
-Operators.bidirectionalChain(ChainPredicateIterator(upred,bpred), NotUP1D(upred))
+Operators.bidirectional_chain(ChainPredicateIterator(upred,bpred), NotUP1D(upred))
 Operators.select(pyHigherLengthUP1D(200))
 shaders_list = [
 		ConstantThicknessShader(5),
diff --git a/release/scripts/freestyle/style_modules/blueprint_squares.py b/release/scripts/freestyle/style_modules/blueprint_squares.py
index 7798acc7d47..4504a83e1cb 100644
--- a/release/scripts/freestyle/style_modules/blueprint_squares.py
+++ b/release/scripts/freestyle/style_modules/blueprint_squares.py
@@ -32,7 +32,7 @@ from shaders import *
 upred = AndUP1D(QuantitativeInvisibilityUP1D(0), ContourUP1D())
 bpred = SameShapeIdBP1D()
 Operators.select(upred)
-Operators.bidirectionalChain(ChainPredicateIterator(upred,bpred), NotUP1D(upred))
+Operators.bidirectional_chain(ChainPredicateIterator(upred,bpred), NotUP1D(upred))
 Operators.select(pyHigherLengthUP1D(200))
 shaders_list = [
 		ConstantThicknessShader(8),
diff --git a/release/scripts/freestyle/style_modules/cartoon.py b/release/scripts/freestyle/style_modules/cartoon.py
index 6ace7e0585a..1e9e164ad4e 100644
--- a/release/scripts/freestyle/style_modules/cartoon.py
+++ b/release/scripts/freestyle/style_modules/cartoon.py
@@ -33,7 +33,7 @@ from PredicatesB1D import *
 from shaders import *
 
 Operators.select(QuantitativeInvisibilityUP1D(0))
-Operators.bidirectionalChain(ChainSilhouetteIterator(), NotUP1D(QuantitativeInvisibilityUP1D(0)))
+Operators.bidirectional_chain(ChainSilhouetteIterator(), NotUP1D(QuantitativeInvisibilityUP1D(0)))
 shaders_list = 	[
 		BezierCurveShader(3),
 		ConstantThicknessShader(4), 
diff --git a/release/scripts/freestyle/style_modules/contour.py b/release/scripts/freestyle/style_modules/contour.py
index c4b3a0f0827..0e4cf38212f 100644
--- a/release/scripts/freestyle/style_modules/contour.py
+++ b/release/scripts/freestyle/style_modules/contour.py
@@ -34,7 +34,7 @@ from shaders import *
 Operators.select(AndUP1D(QuantitativeInvisibilityUP1D(0), ContourUP1D() ) )
 bpred = SameShapeIdBP1D();
 upred = AndUP1D(QuantitativeInvisibilityUP1D(0), ContourUP1D())
-Operators.bidirectionalChain(ChainPredicateIterator(upred, bpred), NotUP1D(QuantitativeInvisibilityUP1D(0)))
+Operators.bidirectional_chain(ChainPredicateIterator(upred, bpred), NotUP1D(QuantitativeInvisibilityUP1D(0)))
 shaders_list =	 [
 		ConstantThicknessShader(5.0),
 		IncreasingColorShader(0.8,0,0,1,0.1,0,0,1)
diff --git a/release/scripts/freestyle/style_modules/curvature2d.py b/release/scripts/freestyle/style_modules/curvature2d.py
index ca84bf21b83..89edb3dadfb 100644
--- a/release/scripts/freestyle/style_modules/curvature2d.py
+++ b/release/scripts/freestyle/style_modules/curvature2d.py
@@ -31,7 +31,7 @@ from logical_operators import *
 from shaders import *
 
 Operators.select(QuantitativeInvisibilityUP1D(0))
-Operators.bidirectionalChain(ChainSilhouetteIterator(), NotUP1D(QuantitativeInvisibilityUP1D(0)))
+Operators.bidirectional_chain(ChainSilhouetteIterator(), NotUP1D(QuantitativeInvisibilityUP1D(0)))
 shaders_list = [
     StrokeTextureShader("smoothAlpha.bmp", Stroke.OPAQUE_MEDIUM, False),
     ConstantThicknessShader(5),
diff --git a/release/scripts/freestyle/style_modules/external_contour.py b/release/scripts/freestyle/style_modules/external_contour.py
index 2a39b79a410..64864978a83 100644
--- a/release/scripts/freestyle/style_modules/external_contour.py
+++ b/release/scripts/freestyle/style_modules/external_contour.py
@@ -35,9 +35,9 @@ from shaders import *
 upred = AndUP1D(QuantitativeInvisibilityUP1D(0), ExternalContourUP1D())
 Operators.select(upred )
 bpred = TrueBP1D();
-Operators.bidirectionalChain(ChainPredicateIterator(upred, bpred), NotUP1D(upred))
+Operators.bidirectional_chain(ChainPredicateIterator(upred, bpred), NotUP1D(upred))
 shaders_list = 	[
 		ConstantThicknessShader(3),
 		ConstantColorShader(0.0, 0.0, 0.0,1)
 		]
-Operators.create(TrueUP1D(), shaders_list)
\ No newline at end of file
+Operators.create(TrueUP1D(), shaders_list)
diff --git a/release/scripts/freestyle/style_modules/external_contour_sketchy.py b/release/scripts/freestyle/style_modules/external_contour_sketchy.py
index 8a4c570b279..dc0162f535b 100644
--- a/release/scripts/freestyle/style_modules/external_contour_sketchy.py
+++ b/release/scripts/freestyle/style_modules/external_contour_sketchy.py
@@ -36,7 +36,7 @@ from shaders import *
 
 upred = AndUP1D(QuantitativeInvisibilityUP1D(0), ExternalContourUP1D()) 
 Operators.select(upred)
-Operators.bidirectionalChain(pySketchyChainingIterator(), NotUP1D(upred))
+Operators.bidirectional_chain(pySketchyChainingIterator(), NotUP1D(upred))
 shaders_list = 	[
 		SamplingShader(4),
 		SpatialNoiseShader(10, 150, 2, 1, 1), 
diff --git a/release/scripts/freestyle/style_modules/external_contour_smooth.py b/release/scripts/freestyle/style_modules/external_contour_smooth.py
index 201dc271388..d2036dbf3be 100644
--- a/release/scripts/freestyle/style_modules/external_contour_smooth.py
+++ b/release/scripts/freestyle/style_modules/external_contour_smooth.py
@@ -34,7 +34,7 @@ from ChainingIterators import *
 upred = AndUP1D(QuantitativeInvisibilityUP1D(0), ExternalContourUP1D())
 Operators.select(upred)
 bpred = TrueBP1D();
-Operators.bidirectionalChain(ChainPredicateIterator(upred, bpred), NotUP1D(upred))
+Operators.bidirectional_chain(ChainPredicateIterator(upred, bpred), NotUP1D(upred))
 shaders_list = 	[
 		SamplingShader(2),
 		IncreasingThicknessShader(4,20), 
diff --git a/release/scripts/freestyle/style_modules/haloing.py b/release/scripts/freestyle/style_modules/haloing.py
index afa46173d54..7b6afedce50 100644
--- a/release/scripts/freestyle/style_modules/haloing.py
+++ b/release/scripts/freestyle/style_modules/haloing.py
@@ -39,7 +39,7 @@ from shaders import *
 id = Id(3,0)
 upred = AndUP1D(QuantitativeInvisibilityUP1D(0) , pyIsOccludedByUP1D(id))
 Operators.select(upred)
-Operators.bidirectionalChain(ChainSilhouetteIterator(), NotUP1D(upred))
+Operators.bidirectional_chain(ChainSilhouetteIterator(), NotUP1D(upred))
 shaders_list = 	[
 		IncreasingThicknessShader(3, 5), 
 		IncreasingColorShader(1,0,0, 1,0,1,0,1),
diff --git a/release/scripts/freestyle/style_modules/ignore_small_occlusions.py b/release/scripts/freestyle/style_modules/ignore_small_occlusions.py
index ff6efa89ade..1623c245940 100644
--- a/release/scripts/freestyle/style_modules/ignore_small_occlusions.py
+++ b/release/scripts/freestyle/style_modules/ignore_small_occlusions.py
@@ -31,8 +31,8 @@ from ChainingIterators import *
 from shaders import *
 
 Operators.select(QuantitativeInvisibilityUP1D(0))
-#Operators.bidirectionalChain(pyFillOcclusionsChainingIterator(0.1))
-Operators.bidirectionalChain(pyFillOcclusionsAbsoluteChainingIterator(12))
+#Operators.bidirectional_chain(pyFillOcclusionsChainingIterator(0.1))
+Operators.bidirectional_chain(pyFillOcclusionsAbsoluteChainingIterator(12))
 shaders_list = 	[
 		SamplingShader(5.0),
 		ConstantThicknessShader(3), 
diff --git a/release/scripts/freestyle/style_modules/invisible_lines.py b/release/scripts/freestyle/style_modules/invisible_lines.py
index ea509463bfd..602e3ea0a5b 100644
--- a/release/scripts/freestyle/style_modules/invisible_lines.py
+++ b/release/scripts/freestyle/style_modules/invisible_lines.py
@@ -33,7 +33,7 @@ from shaders import *
 
 upred = NotUP1D(QuantitativeInvisibilityUP1D(0))
 Operators.select(upred)
-Operators.bidirectionalChain(ChainSilhouetteIterator(), NotUP1D(upred))
+Operators.bidirectional_chain(ChainSilhouetteIterator(), NotUP1D(upred))
 shaders_list = 	[
 		SamplingShader(5.0),
 		ConstantThicknessShader(3.0), 
diff --git a/release/scripts/freestyle/style_modules/japanese_bigbrush.py b/release/scripts/freestyle/style_modules/japanese_bigbrush.py
index 7f109598aaa..a4cd392a79b 100644
--- a/release/scripts/freestyle/style_modules/japanese_bigbrush.py
+++ b/release/scripts/freestyle/style_modules/japanese_bigbrush.py
@@ -33,11 +33,11 @@ from Functions0D import *
 from shaders import *
 
 Operators.select(QuantitativeInvisibilityUP1D(0))
-Operators.bidirectionalChain(ChainSilhouetteIterator(),NotUP1D(QuantitativeInvisibilityUP1D(0)))
+Operators.bidirectional_chain(ChainSilhouetteIterator(),NotUP1D(QuantitativeInvisibilityUP1D(0)))
 ## Splits strokes at points of highest 2D curavture 
 ## when there are too many abrupt turns in it
 func = pyInverseCurvature2DAngleF0D()
-Operators.recursiveSplit(func,  pyParameterUP0D(0.2,0.8), NotUP1D(pyHigherNumberOfTurnsUP1D(3, 0.5)), 2)
+Operators.recursive_split(func,  pyParameterUP0D(0.2,0.8), NotUP1D(pyHigherNumberOfTurnsUP1D(3, 0.5)), 2)
 ## Keeps only long enough strokes
 Operators.select(pyHigherLengthUP1D(100))
 ## Sorts so as to draw the longest strokes first
diff --git a/release/scripts/freestyle/style_modules/long_anisotropically_dense.py b/release/scripts/freestyle/style_modules/long_anisotropically_dense.py
index 565519642f7..b06642ff40d 100644
--- a/release/scripts/freestyle/style_modules/long_anisotropically_dense.py
+++ b/release/scripts/freestyle/style_modules/long_anisotropically_dense.py
@@ -61,7 +61,7 @@ class pyDensityUP1D(UnaryPredicate1D):
 		return 0
 
 Operators.select(QuantitativeInvisibilityUP1D(0))
-Operators.bidirectionalChain(ChainSilhouetteIterator(),NotUP1D(QuantitativeInvisibilityUP1D(0)))
+Operators.bidirectional_chain(ChainSilhouetteIterator(),NotUP1D(QuantitativeInvisibilityUP1D(0)))
 Operators.select(pyHigherLengthUP1D(40))
 ## selects lines having a high anisotropic a priori density
 Operators.select(pyHighDensityAnisotropyUP1D(0.3,4))
diff --git a/release/scripts/freestyle/style_modules/multiple_parameterization.py b/release/scripts/freestyle/style_modules/multiple_parameterization.py
index 3f0409db5fa..0e9dc452827 100644
--- a/release/scripts/freestyle/style_modules/multiple_parameterization.py
+++ b/release/scripts/freestyle/style_modules/multiple_parameterization.py
@@ -39,7 +39,7 @@ from shaders import *
 Operators.select(QuantitativeInvisibilityUP1D(0))
 ## Chain following the same nature, but without the restriction
 ## of staying inside the selection (0).
-Operators.bidirectionalChain(ChainSilhouetteIterator(0))
+Operators.bidirectional_chain(ChainSilhouetteIterator(0))
 shaders_list = 	[
 		SamplingShader(20),
 		IncreasingThicknessShader(1.5, 30), 
diff --git a/release/scripts/freestyle/style_modules/nature.py b/release/scripts/freestyle/style_modules/nature.py
index b5481a8e519..e8d5ec72a1d 100644
--- a/release/scripts/freestyle/style_modules/nature.py
+++ b/release/scripts/freestyle/style_modules/nature.py
@@ -35,7 +35,7 @@ from PredicatesB1D import *
 from shaders import *
 
 Operators.select(pyNatureUP1D(Nature.SILHOUETTE))
-Operators.bidirectionalChain(ChainSilhouetteIterator(),NotUP1D( pyNatureUP1D( Nature.SILHOUETTE) ) )
+Operators.bidirectional_chain(ChainSilhouetteIterator(),NotUP1D( pyNatureUP1D( Nature.SILHOUETTE) ) )
 shaders_list = 	[
 		IncreasingThicknessShader(3, 10), 
 		IncreasingColorShader(0.0,0.0,0.0, 1, 0.8,0,0,1)
diff --git a/release/scripts/freestyle/style_modules/near_lines.py b/release/scripts/freestyle/style_modules/near_lines.py
index 565bca1fe1f..de5d8ce0813 100644
--- a/release/scripts/freestyle/style_modules/near_lines.py
+++ b/release/scripts/freestyle/style_modules/near_lines.py
@@ -35,7 +35,7 @@ from shaders import *
 
 upred = AndUP1D(QuantitativeInvisibilityUP1D(0), pyZSmallerUP1D(0.5, IntegrationType.MEAN)) 
 Operators.select(upred)
-Operators.bidirectionalChain(ChainSilhouetteIterator(), NotUP1D(upred))
+Operators.bidirectional_chain(ChainSilhouetteIterator(), NotUP1D(upred))
 shaders_list = 	[
 		TextureAssignerShader(-1),
 		ConstantThicknessShader(5), 
diff --git a/release/scripts/freestyle/style_modules/occluded_by_specific_object.py b/release/scripts/freestyle/style_modules/occluded_by_specific_object.py
index 09ce39d5dd6..6154aa1e080 100644
--- a/release/scripts/freestyle/style_modules/occluded_by_specific_object.py
+++ b/release/scripts/freestyle/style_modules/occluded_by_specific_object.py
@@ -36,7 +36,7 @@ id = Id(3,0)
 upred = AndUP1D(NotUP1D(QuantitativeInvisibilityUP1D(0)),
 pyIsInOccludersListUP1D(id))
 Operators.select(upred)
-Operators.bidirectionalChain(ChainSilhouetteIterator(), NotUP1D(upred))
+Operators.bidirectional_chain(ChainSilhouetteIterator(), NotUP1D(upred))
 shaders_list = 	[
 		SamplingShader(5),
 		ConstantThicknessShader(3), 
diff --git a/release/scripts/freestyle/style_modules/parameter_editor.py b/release/scripts/freestyle/style_modules/parameter_editor.py
index 8ec33732eea..64a68e1b6dc 100644
--- a/release/scripts/freestyle/style_modules/parameter_editor.py
+++ b/release/scripts/freestyle/style_modules/parameter_editor.py
@@ -1057,25 +1057,25 @@ def process(layer_name, lineset_name):
     if linestyle.use_chaining:
         if linestyle.chaining == "PLAIN":
             if linestyle.same_object:
-                Operators.bidirectionalChain(ChainSilhouetteIterator(), NotUP1D(upred))
+                Operators.bidirectional_chain(ChainSilhouetteIterator(), NotUP1D(upred))
             else:
-                Operators.bidirectionalChain(ChainPredicateIterator(upred, TrueBP1D()), NotUP1D(upred))
+                Operators.bidirectional_chain(ChainPredicateIterator(upred, TrueBP1D()), NotUP1D(upred))
         elif linestyle.chaining == "SKETCHY":
             if linestyle.same_object:
-                Operators.bidirectionalChain(pySketchyChainSilhouetteIterator(linestyle.rounds))
+                Operators.bidirectional_chain(pySketchyChainSilhouetteIterator(linestyle.rounds))
             else:
-                Operators.bidirectionalChain(pySketchyChainingIterator(linestyle.rounds))
+                Operators.bidirectional_chain(pySketchyChainingIterator(linestyle.rounds))
     else:
         Operators.chain(ChainPredicateIterator(FalseUP1D(), FalseBP1D()), NotUP1D(upred))
     # split chains
     if linestyle.material_boundary:
-        Operators.sequentialSplit(MaterialBoundaryUP0D())
+        Operators.sequential_split(MaterialBoundaryUP0D())
     if linestyle.use_min_angle or linestyle.use_max_angle:
         min_angle = linestyle.min_angle if linestyle.use_min_angle else None
         max_angle = linestyle.max_angle if linestyle.use_max_angle else None
-        Operators.sequentialSplit(Curvature2DAngleThresholdUP0D(min_angle, max_angle))
+        Operators.sequential_split(Curvature2DAngleThresholdUP0D(min_angle, max_angle))
     if linestyle.use_split_length:
-        Operators.sequentialSplit(Length2DThresholdUP0D(linestyle.split_length), 1.0)
+        Operators.sequential_split(Length2DThresholdUP0D(linestyle.split_length), 1.0)
     if linestyle.use_split_pattern:
         pattern = []
         if linestyle.split_dash1 > 0 and linestyle.split_gap1 > 0:
@@ -1090,9 +1090,9 @@ def process(layer_name, lineset_name):
         if len(pattern) > 0:
             sampling = 1.0
             controller = SplitPatternController(pattern, sampling)
-            Operators.sequentialSplit(SplitPatternStartingUP0D(controller),
-                                      SplitPatternStoppingUP0D(controller),
-                                      sampling)
+            Operators.sequential_split(SplitPatternStartingUP0D(controller),
+                                       SplitPatternStoppingUP0D(controller),
+                                       sampling)
     # select chains
     if linestyle.use_min_length or linestyle.use_max_length:
         min_length = linestyle.min_length if linestyle.use_min_length else None
diff --git a/release/scripts/freestyle/style_modules/polygonalize.py b/release/scripts/freestyle/style_modules/polygonalize.py
index 4446c4c1dcc..a1f2f00d658 100644
--- a/release/scripts/freestyle/style_modules/polygonalize.py
+++ b/release/scripts/freestyle/style_modules/polygonalize.py
@@ -30,11 +30,11 @@ from ChainingIterators import *
 from shaders import *
 
 Operators.select(QuantitativeInvisibilityUP1D(0))
-Operators.bidirectionalChain(ChainSilhouetteIterator(),NotUP1D(QuantitativeInvisibilityUP1D(0)))
+Operators.bidirectional_chain(ChainSilhouetteIterator(),NotUP1D(QuantitativeInvisibilityUP1D(0)))
 shaders_list = 	[
 		SamplingShader(2.0),
 		ConstantThicknessShader(3), 
 		ConstantColorShader(0.0,0.0,0.0),
 		PolygonalizationShader(8)
 		]
-Operators.create(TrueUP1D(), shaders_list)
\ No newline at end of file
+Operators.create(TrueUP1D(), shaders_list)
diff --git a/release/scripts/freestyle/style_modules/qi0.py b/release/scripts/freestyle/style_modules/qi0.py
index d35d23cb7c3..7b67a207930 100644
--- a/release/scripts/freestyle/style_modules/qi0.py
+++ b/release/scripts/freestyle/style_modules/qi0.py
@@ -32,10 +32,10 @@ from ChainingIterators import *
 from shaders import *
 
 Operators.select(QuantitativeInvisibilityUP1D(0))
-Operators.bidirectionalChain(ChainSilhouetteIterator(), NotUP1D(QuantitativeInvisibilityUP1D(0)))
+Operators.bidirectional_chain(ChainSilhouetteIterator(), NotUP1D(QuantitativeInvisibilityUP1D(0)))
 shaders_list = 	[
 		SamplingShader(5.0),
 		ConstantThicknessShader(4.0), 
 		ConstantColorShader(0.0,0.0,0.0)
 		]
-Operators.create(TrueUP1D(), shaders_list)
\ No newline at end of file
+Operators.create(TrueUP1D(), shaders_list)
diff --git a/release/scripts/freestyle/style_modules/qi0_not_external_contour.py b/release/scripts/freestyle/style_modules/qi0_not_external_contour.py
index eed41af32b4..59b68b9ed29 100644
--- a/release/scripts/freestyle/style_modules/qi0_not_external_contour.py
+++ b/release/scripts/freestyle/style_modules/qi0_not_external_contour.py
@@ -31,7 +31,7 @@ from logical_operators import *
 
 upred = AndUP1D(QuantitativeInvisibilityUP1D(0), ExternalContourUP1D())
 Operators.select(upred)
-Operators.bidirectionalChain(ChainSilhouetteIterator(), NotUP1D(upred))
+Operators.bidirectional_chain(ChainSilhouetteIterator(), NotUP1D(upred))
 shaders_list = 	[
 		SamplingShader(4),
 		SpatialNoiseShader(4, 150, 2, True, True), 
diff --git a/release/scripts/freestyle/style_modules/qi1.py b/release/scripts/freestyle/style_modules/qi1.py
index 8d248376138..4d459d12a21 100644
--- a/release/scripts/freestyle/style_modules/qi1.py
+++ b/release/scripts/freestyle/style_modules/qi1.py
@@ -33,7 +33,7 @@ from PredicatesB1D import *
 from shaders import *
 
 Operators.select(QuantitativeInvisibilityUP1D(1))
-Operators.bidirectionalChain(ChainSilhouetteIterator(), NotUP1D(QuantitativeInvisibilityUP1D(1)))
+Operators.bidirectional_chain(ChainSilhouetteIterator(), NotUP1D(QuantitativeInvisibilityUP1D(1)))
 shaders_list = 	[
 		SamplingShader(5.0),
 		ConstantThicknessShader(3), 
diff --git a/release/scripts/freestyle/style_modules/qi2.py b/release/scripts/freestyle/style_modules/qi2.py
index ba5e97b6982..1ba33ecead5 100644
--- a/release/scripts/freestyle/style_modules/qi2.py
+++ b/release/scripts/freestyle/style_modules/qi2.py
@@ -33,10 +33,10 @@ from PredicatesB1D import *
 from shaders import *
 
 Operators.select(QuantitativeInvisibilityUP1D(2))
-Operators.bidirectionalChain(ChainSilhouetteIterator(), NotUP1D(QuantitativeInvisibilityUP1D(2)))
+Operators.bidirectional_chain(ChainSilhouetteIterator(), NotUP1D(QuantitativeInvisibilityUP1D(2)))
 shaders_list = 	[
 		SamplingShader(10),
 		ConstantThicknessShader(1.5), 
 		ConstantColorShader(0.7,0.7,0.7, 1)
 		]
-Operators.create(TrueUP1D(), shaders_list)
\ No newline at end of file
+Operators.create(TrueUP1D(), shaders_list)
diff --git a/release/scripts/freestyle/style_modules/sequentialsplit_sketchy.py b/release/scripts/freestyle/style_modules/sequentialsplit_sketchy.py
index d72a3730e25..8eda37bfc3c 100644
--- a/release/scripts/freestyle/style_modules/sequentialsplit_sketchy.py
+++ b/release/scripts/freestyle/style_modules/sequentialsplit_sketchy.py
@@ -35,11 +35,11 @@ from Functions0D import *
 
 upred = QuantitativeInvisibilityUP1D(0)
 Operators.select(upred)
-Operators.bidirectionalChain(ChainSilhouetteIterator(), NotUP1D(upred))
+Operators.bidirectional_chain(ChainSilhouetteIterator(), NotUP1D(upred))
 ## starting and stopping predicates:
 start = pyVertexNatureUP0D(Nature.NON_T_VERTEX)
 stop = pyBackTVertexUP0D()
-Operators.sequentialSplit(start, stop, 10)
+Operators.sequential_split(start, stop, 10)
 shaders_list = [
 		SpatialNoiseShader(7, 120, 2, True, True), 
 		IncreasingThicknessShader(5, 8), 
diff --git a/release/scripts/freestyle/style_modules/shaders.py b/release/scripts/freestyle/style_modules/shaders.py
index 73fddc2abf4..568a3309fda 100644
--- a/release/scripts/freestyle/style_modules/shaders.py
+++ b/release/scripts/freestyle/style_modules/shaders.py
@@ -1,4 +1,5 @@
 from freestyle_init import *
+from Freestyle import ContextFunctions as CF
 from PredicatesU0D import *
 from PredicatesB1D import *
 from PredicatesU1D import *
@@ -1192,7 +1193,7 @@ class pyDummyShader(StrokeShader):
 
 class pyDebugShader(StrokeShader):
 	def shade(self, stroke):
-		fe = GetSelectedFEdgeCF()
+		fe = CF.get_selected_fedge()
 		id1 = fe.first_svertex.id
 		id2 = fe.second_svertex.id
 		#print(id1.first, id1.second)
diff --git a/release/scripts/freestyle/style_modules/sketchy_multiple_parameterization.py b/release/scripts/freestyle/style_modules/sketchy_multiple_parameterization.py
index 76ab4343316..98050c37eb9 100644
--- a/release/scripts/freestyle/style_modules/sketchy_multiple_parameterization.py
+++ b/release/scripts/freestyle/style_modules/sketchy_multiple_parameterization.py
@@ -35,7 +35,7 @@ from shaders import *
 
 Operators.select(QuantitativeInvisibilityUP1D(0))
 ## 0: don't restrict to selection
-Operators.bidirectionalChain(pySketchyChainSilhouetteIterator(3,0))
+Operators.bidirectional_chain(pySketchyChainSilhouetteIterator(3,0))
 shaders_list = 	[
 		SamplingShader(2),
 		SpatialNoiseShader(15, 120, 2, True, True),
diff --git a/release/scripts/freestyle/style_modules/sketchy_topology_broken.py b/release/scripts/freestyle/style_modules/sketchy_topology_broken.py
index eb600e62af7..49f40e965c7 100644
--- a/release/scripts/freestyle/style_modules/sketchy_topology_broken.py
+++ b/release/scripts/freestyle/style_modules/sketchy_topology_broken.py
@@ -35,7 +35,7 @@ from shaders import *
 Operators.select(QuantitativeInvisibilityUP1D(0))
 ## Chain 3 times each ViewEdge indpendantly from the 
 ## initial objects topology
-Operators.bidirectionalChain(pySketchyChainingIterator(3))
+Operators.bidirectional_chain(pySketchyChainingIterator(3))
 shaders_list = [
     SamplingShader(4),
     SpatialNoiseShader(6, 120, 2, True, True), 
diff --git a/release/scripts/freestyle/style_modules/sketchy_topology_preserved.py b/release/scripts/freestyle/style_modules/sketchy_topology_preserved.py
index 0c2d9d759a6..8111f449bb3 100644
--- a/release/scripts/freestyle/style_modules/sketchy_topology_preserved.py
+++ b/release/scripts/freestyle/style_modules/sketchy_topology_preserved.py
@@ -35,7 +35,7 @@ from shaders import *
 
 upred = QuantitativeInvisibilityUP1D(0)
 Operators.select(upred)
-Operators.bidirectionalChain(pySketchyChainSilhouetteIterator(3,1))
+Operators.bidirectional_chain(pySketchyChainSilhouetteIterator(3,1))
 shaders_list = 	[
 		SamplingShader(4),
 		SpatialNoiseShader(20, 220, 2, True, True),
diff --git a/release/scripts/freestyle/style_modules/split_at_highest_2d_curvatures.py b/release/scripts/freestyle/style_modules/split_at_highest_2d_curvatures.py
index 52cc10a9c60..3c7ea0c3f73 100644
--- a/release/scripts/freestyle/style_modules/split_at_highest_2d_curvatures.py
+++ b/release/scripts/freestyle/style_modules/split_at_highest_2d_curvatures.py
@@ -33,9 +33,9 @@ from PredicatesU1D import *
 from Functions0D import *
 
 Operators.select(QuantitativeInvisibilityUP1D(0))
-Operators.bidirectionalChain(ChainSilhouetteIterator(), NotUP1D(QuantitativeInvisibilityUP1D(0)))
+Operators.bidirectional_chain(ChainSilhouetteIterator(), NotUP1D(QuantitativeInvisibilityUP1D(0)))
 func = pyInverseCurvature2DAngleF0D()
-Operators.recursiveSplit(func,  pyParameterUP0D(0.4,0.6), NotUP1D(pyHigherLengthUP1D(100)), 2)
+Operators.recursive_split(func,  pyParameterUP0D(0.4,0.6), NotUP1D(pyHigherLengthUP1D(100)), 2)
 shaders_list = [ConstantThicknessShader(10), IncreasingColorShader(1,0,0,1,0,1,0,1), TextureAssignerShader(3)]
 Operators.create(TrueUP1D(), shaders_list)
 
diff --git a/release/scripts/freestyle/style_modules/split_at_tvertices.py b/release/scripts/freestyle/style_modules/split_at_tvertices.py
index 78f781dd290..ccf76950efc 100644
--- a/release/scripts/freestyle/style_modules/split_at_tvertices.py
+++ b/release/scripts/freestyle/style_modules/split_at_tvertices.py
@@ -32,11 +32,11 @@ from PredicatesU0D import *
 from Functions0D import *
 
 Operators.select(QuantitativeInvisibilityUP1D(0))
-Operators.bidirectionalChain(ChainSilhouetteIterator(), NotUP1D(QuantitativeInvisibilityUP1D(0)))
+Operators.bidirectional_chain(ChainSilhouetteIterator(), NotUP1D(QuantitativeInvisibilityUP1D(0)))
 start = pyVertexNatureUP0D(Nature.T_VERTEX)
 ## use the same predicate to decide where to start and where to stop 
 ## the strokes:
-Operators.sequentialSplit(start, start, 10)
+Operators.sequential_split(start, start, 10)
 shaders_list = [ConstantThicknessShader(5), IncreasingColorShader(1,0,0,1,0,1,0,1), TextureAssignerShader(3)]
 Operators.create(TrueUP1D(), shaders_list)
 
diff --git a/release/scripts/freestyle/style_modules/stroke_texture.py b/release/scripts/freestyle/style_modules/stroke_texture.py
index 035967dc39c..eb0878c2f14 100644
--- a/release/scripts/freestyle/style_modules/stroke_texture.py
+++ b/release/scripts/freestyle/style_modules/stroke_texture.py
@@ -32,7 +32,7 @@ from shaders import *
 from ChainingIterators import *
 
 Operators.select(QuantitativeInvisibilityUP1D(0))
-Operators.bidirectionalChain(ChainSilhouetteIterator(), NotUP1D(QuantitativeInvisibilityUP1D(0)))
+Operators.bidirectional_chain(ChainSilhouetteIterator(), NotUP1D(QuantitativeInvisibilityUP1D(0)))
 shaders_list = 	[
 		SamplingShader(3),
 		BezierCurveShader(4),
diff --git a/release/scripts/freestyle/style_modules/suggestive.py b/release/scripts/freestyle/style_modules/suggestive.py
index 39d8515ed6c..c27409abffb 100644
--- a/release/scripts/freestyle/style_modules/suggestive.py
+++ b/release/scripts/freestyle/style_modules/suggestive.py
@@ -35,7 +35,7 @@ from shaders import *
 
 upred = AndUP1D(pyNatureUP1D(Nature.SUGGESTIVE_CONTOUR), QuantitativeInvisibilityUP1D(0))
 Operators.select(upred)
-Operators.bidirectionalChain(ChainSilhouetteIterator(), NotUP1D(upred))
+Operators.bidirectional_chain(ChainSilhouetteIterator(), NotUP1D(upred))
 shaders_list = 	[
 		IncreasingThicknessShader(1, 3), 
 		ConstantColorShader(0.2,0.2,0.2, 1)
diff --git a/release/scripts/freestyle/style_modules/thickness_fof_depth_discontinuity.py b/release/scripts/freestyle/style_modules/thickness_fof_depth_discontinuity.py
index 8394aa1bde4..9fd8d061489 100644
--- a/release/scripts/freestyle/style_modules/thickness_fof_depth_discontinuity.py
+++ b/release/scripts/freestyle/style_modules/thickness_fof_depth_discontinuity.py
@@ -30,7 +30,7 @@ from logical_operators import *
 from shaders import *
 
 Operators.select(QuantitativeInvisibilityUP1D(0))
-Operators.bidirectionalChain(ChainSilhouetteIterator(), NotUP1D(QuantitativeInvisibilityUP1D(0)))
+Operators.bidirectional_chain(ChainSilhouetteIterator(), NotUP1D(QuantitativeInvisibilityUP1D(0)))
 shaders_list = [
     SamplingShader(1),
     ConstantThicknessShader(3), 
diff --git a/release/scripts/freestyle/style_modules/tipremover.py b/release/scripts/freestyle/style_modules/tipremover.py
index 3e495b7d332..0f83190b14b 100644
--- a/release/scripts/freestyle/style_modules/tipremover.py
+++ b/release/scripts/freestyle/style_modules/tipremover.py
@@ -32,11 +32,11 @@ from ChainingIterators import *
 from shaders import *
 
 Operators.select(QuantitativeInvisibilityUP1D(0))
-Operators.bidirectionalChain(ChainSilhouetteIterator(), NotUP1D(QuantitativeInvisibilityUP1D(0)))
+Operators.bidirectional_chain(ChainSilhouetteIterator(), NotUP1D(QuantitativeInvisibilityUP1D(0)))
 shaders_list = 	[
 		SamplingShader(5),
 		ConstantThicknessShader(3), 
 		ConstantColorShader(0,0,0),
 		TipRemoverShader(20)
 		]
-Operators.create(TrueUP1D(), shaders_list)
\ No newline at end of file
+Operators.create(TrueUP1D(), shaders_list)
diff --git a/release/scripts/freestyle/style_modules/tvertex_remover.py b/release/scripts/freestyle/style_modules/tvertex_remover.py
index c328f4c98ec..109218b63fd 100644
--- a/release/scripts/freestyle/style_modules/tvertex_remover.py
+++ b/release/scripts/freestyle/style_modules/tvertex_remover.py
@@ -32,7 +32,7 @@ from PredicatesB1D import *
 from shaders import *
 
 Operators.select(QuantitativeInvisibilityUP1D(0))
-Operators.bidirectionalChain(ChainSilhouetteIterator(), NotUP1D(QuantitativeInvisibilityUP1D(0)))
+Operators.bidirectional_chain(ChainSilhouetteIterator(), NotUP1D(QuantitativeInvisibilityUP1D(0)))
 shaders_list = 	[
 		IncreasingThicknessShader(3, 5), 
 		ConstantColorShader(0.2,0.2,0.2, 1),
diff --git a/release/scripts/freestyle/style_modules/uniformpruning_zsort.py b/release/scripts/freestyle/style_modules/uniformpruning_zsort.py
index c8537cd4241..b4b1b778f7e 100644
--- a/release/scripts/freestyle/style_modules/uniformpruning_zsort.py
+++ b/release/scripts/freestyle/style_modules/uniformpruning_zsort.py
@@ -8,8 +8,8 @@ from Functions1D import *
 from shaders import *
 
 Operators.select(QuantitativeInvisibilityUP1D(0))
-Operators.bidirectionalChain(ChainSilhouetteIterator())
-#Operators.sequentialSplit(pyVertexNatureUP0D(Nature.VIEW_VERTEX), 2)
+Operators.bidirectional_chain(ChainSilhouetteIterator())
+#Operators.sequential_split(pyVertexNatureUP0D(Nature.VIEW_VERTEX), 2)
 Operators.sort(pyZBP1D())
 shaders_list = 	[
 		StrokeTextureShader("smoothAlpha.bmp", Stroke.OPAQUE_MEDIUM, False),