Freestyle: New line style options for sorting and chain selection.

The following two sort keys are added for sorting chains.

* Projected X - Sort by the projected X value in the image coordinate system.
* Projected Y - Sort by the projected Y value in the image coordinate system.

A new line style option for the selection of first N chains is also added.

Moreover, the chain sorting and chain selection operations are now executed
in this order instead of the reverse order used previously.  The UI has also
changed accordingly.  This functional change is backward compatible and
won't result in visual differences.

release/scripts/freestyle/modules/freestyle/predicates.py

@@ -82,6 +82,8 @@ __all__ = (
     "pyNatureUP1D",
     "pyParameterUP0D",
     "pyParameterUP0DGoodOne",
+    "pyProjectedXBP1D",
+    "pyProjectedYBP1D",
     "pyShapeIdListUP1D",
     "pyShapeIdUP1D",
     "pyShuffleBP1D",
@@ -135,6 +137,8 @@ from freestyle.functions import (
     GetCurvilinearAbscissaF0D,
     GetDirectionalViewMapDensityF1D,
     GetOccludersF1D,
+    GetProjectedXF1D,
+    GetProjectedYF1D,
     GetProjectedZF1D,
     GetShapeF1D,
     GetSteerableViewMapDensityF1D,
@@ -596,6 +600,24 @@ class pyZBP1D(BinaryPredicate1D):
         return (self.func(i1) > self.func(i2))
 
 
+class pyProjectedXBP1D(BinaryPredicate1D):
+    def __init__(self, iType=IntegrationType.MEAN):
+        BinaryPredicate1D.__init__(self)
+        self.func = GetProjectedXF1D(iType)
+
+    def __call__(self, i1, i2):
+        return (self.func(i1) > self.func(i2))
+
+
+class pyProjectedYBP1D(BinaryPredicate1D):
+    def __init__(self, iType=IntegrationType.MEAN):
+        BinaryPredicate1D.__init__(self)
+        self.func = GetProjectedYF1D(iType)
+
+    def __call__(self, i1, i2):
+        return (self.func(i1) > self.func(i2))
+
+
 class pyZDiscontinuityBP1D(BinaryPredicate1D):
     def __init__(self, iType=IntegrationType.MEAN):
         BinaryPredicate1D.__init__(self)

release/scripts/freestyle/modules/parameter_editor.py

@@ -62,7 +62,10 @@ from freestyle.predicates import (
     TrueBP1D,
     TrueUP1D,
     WithinImageBoundaryUP1D,
+    pyNFirstUP1D,
     pyNatureUP1D,
+    pyProjectedXBP1D,
+    pyProjectedYBP1D,
     pyZBP1D,
     )
 from freestyle.shaders import (
@@ -1006,11 +1009,6 @@ def process(layer_name, lineset_name):
             Operators.sequential_split(SplitPatternStartingUP0D(controller),
                                        SplitPatternStoppingUP0D(controller),
                                        sampling)
-    # select chains
-    if linestyle.use_length_min or linestyle.use_length_max:
-        length_min = linestyle.length_min if linestyle.use_length_min else None
-        length_max = linestyle.length_max if linestyle.use_length_max else None
-        Operators.select(LengthThresholdUP1D(length_min, length_max))
     # sort selected chains
     if linestyle.use_sorting:
         integration = integration_types.get(linestyle.integration_type, IntegrationType.MEAN)
@@ -1018,9 +1016,20 @@ def process(layer_name, lineset_name):
             bpred = pyZBP1D(integration)
         elif linestyle.sort_key == '2D_LENGTH':
             bpred = Length2DBP1D()
+        elif linestyle.sort_key == 'PROJECTED_X':
+            bpred = pyProjectedXBP1D(integration)
+        elif linestyle.sort_key == 'PROJECTED_Y':
+            bpred = pyProjectedYBP1D(integration)
         if linestyle.sort_order == 'REVERSE':
             bpred = NotBP1D(bpred)
         Operators.sort(bpred)
+    # select chains
+    if linestyle.use_length_min or linestyle.use_length_max:
+        length_min = linestyle.length_min if linestyle.use_length_min else None
+        length_max = linestyle.length_max if linestyle.use_length_max else None
+        Operators.select(LengthThresholdUP1D(length_min, length_max))
+    if linestyle.use_chain_count:
+        Operators.select(pyNFirstUP1D(linestyle.chain_count))
     # prepare a list of stroke shaders
     shaders_list = []
     for m in linestyle.geometry_modifiers: