NURBS Curve Degree Elevate & Reduce nodes.

ee61b016 · Ilya Portnov · d762226b · ee61b016 · ee61b016 · ee61b016
--- a/index.md
+++ b/index.md
@@ -77,6 +77,9 @@
    SvRefineNurbsCurveNode
    SvCurveRemoveExcessiveKnotsNode
    ---
+    SvCurveElevateDegreeNode
+    SvCurveReduceDegreeNode
+    ---
    SvAdaptivePlotNurbsCurveNode

 ## Curves @ Bezier

--- a/nodes/curve/elevate_degree.py
+++ b/nodes/curve/elevate_degree.py
+# This file is part of project Sverchok. It's copyrighted by the contributors
+# recorded in the version control history of the file, available from
+# its original location https://github.com/nortikin/sverchok/commit/master
+#  
+# SPDX-License-Identifier: GPL3
+# License-Filename: LICENSE
+
+import bpy
+from bpy.props import FloatProperty, EnumProperty, BoolProperty, IntProperty
+
+from sverchok.node_tree import SverchCustomTreeNode
+from sverchok.data_structure import updateNode, zip_long_repeat, ensure_nesting_level, get_data_nesting_level, repeat_last_for_length
+from sverchok.utils.curve import SvCurve
+from sverchok.utils.curve.nurbs import SvNurbsCurve
+
+class SvCurveElevateDegreeNode(bpy.types.Node, SverchCustomTreeNode):
+    """
+    Triggers: Elevate Degree
+    Tooltip: Elevate degree of a NURBS curve
+    """
+    bl_idname = 'SvCurveElevateDegreeNode'
+    bl_label = 'Elevate Degree (NURBS Curve)'
+    bl_icon = 'OUTLINER_OB_EMPTY'
+    sv_icon = 'SV_CURVE_INSERT_KNOT'
+
+    modes = [
+            ('DELTA', "Elevate by", "Specify difference between current degree and target degree", 0),
+            ('TARGET', "Set degree", "Specify target degree", 1)
+        ]
+
+    def update_sockets(self, context):
+        self.inputs['Degree'].label = "Delta" if self.mode == 'DELTA' else "Degree"
+        updateNode(self, context)
+
+    mode : EnumProperty(
+            name = "Mode",
+            description = "How new curve degree is specified",
+            items = modes,
+            update = update_sockets)
+
+    degree : IntProperty(
+            name = "Degree",
+            description = "Target degree or degree delta",
+            min = 0,
+            default = 1,
+            update = updateNode)
+
+    def draw_buttons(self, context, layout):
+        layout.prop(self, 'mode', text='')
+
+    def sv_init(self, context):
+        self.inputs.new('SvCurveSocket', "Curve")
+        self.inputs.new('SvStringsSocket', 'Degree').prop_name = 'degree'
+        self.outputs.new('SvCurveSocket', 'Curve')
+
+    def process(self):
+        if not any(socket.is_linked for socket in self.outputs):
+            return
+
+        curve_s = self.inputs['Curve'].sv_get()
+        degree_s = self.inputs['Degree'].sv_get()
+
+        input_level = get_data_nesting_level(curve_s, data_types=(SvCurve,))
+        flat_output = input_level < 2
+        curve_s = ensure_nesting_level(curve_s, 2, data_types=(SvCurve,))
+        degree_s = ensure_nesting_level(degree_s, 2)
+
+        curves_out = []
+        for params in zip_long_repeat(curve_s, degree_s):
+            new_curves = []
+            for curve, degree in zip_long_repeat(*params):
+                curve = SvNurbsCurve.to_nurbs(curve)
+                if curve is None:
+                    raise Exception("One of curves is not NURBS")
+                if self.mode == 'DELTA':
+                    kwargs = dict(delta = degree)
+                else:
+                    kwargs = dict(target = degree)
+                curve = curve.elevate_degree(**kwargs)
+                new_curves.append(curve)
+            if flat_output:
+                curves_out.extend(new_curves)
+            else:
+                curves_out.append(new_curves)
+
+        self.outputs['Curve'].sv_set(curves_out)
+
+def register():
+    bpy.utils.register_class(SvCurveElevateDegreeNode)
+
+def unregister():
+    bpy.utils.unregister_class(SvCurveElevateDegreeNode)
+
--- a/nodes/curve/reduce_degree.py
+++ b/nodes/curve/reduce_degree.py
+# This file is part of project Sverchok. It's copyrighted by the contributors
+# recorded in the version control history of the file, available from
+# its original location https://github.com/nortikin/sverchok/commit/master
+#  
+# SPDX-License-Identifier: GPL3
+# License-Filename: LICENSE
+
+import bpy
+from bpy.props import FloatProperty, EnumProperty, BoolProperty, IntProperty
+
+from sverchok.node_tree import SverchCustomTreeNode
+from sverchok.data_structure import updateNode, zip_long_repeat, ensure_nesting_level, get_data_nesting_level, repeat_last_for_length
+from sverchok.utils.curve import SvCurve
+from sverchok.utils.curve.nurbs import SvNurbsCurve
+
+class SvCurveReduceDegreeNode(bpy.types.Node, SverchCustomTreeNode):
+    """
+    Triggers: Reduce Degree
+    Tooltip: Reduce degree of a NURBS curve
+    """
+    bl_idname = 'SvCurveReduceDegreeNode'
+    bl_label = 'Reduce Degree (NURBS Curve)'
+    bl_icon = 'OUTLINER_OB_EMPTY'
+    sv_icon = 'SV_CURVE_INSERT_KNOT'
+
+    modes = [
+            ('DELTA', "Reduce by", "Specify difference between current degree and target degree", 0),
+            ('TARGET', "Set degree", "Specify target degree", 1)
+        ]
+
+    def update_sockets(self, context):
+        self.inputs['Degree'].label = "Delta" if self.mode == 'DELTA' else "Degree"
+        updateNode(self, context)
+
+    mode : EnumProperty(
+            name = "Mode",
+            description = "How new curve degree is specified",
+            items = modes,
+            update = update_sockets)
+
+    degree : IntProperty(
+            name = "Degree",
+            description = "Target degree or degree delta",
+            min = 0,
+            default = 1,
+            update = updateNode)
+
+    tolerance : FloatProperty(
+            name = "Tolerance",
+            description = "Error tolerance",
+            min = 0.0,
+            default = 1e-4,
+            precision = 8,
+            update = updateNode)
+
+    if_possible : BoolProperty(
+            name = "If possible",
+            description = "Don't fail when trying to reduce the curve's degree too many times, just reduce it as much as possible",
+            default = False,
+            update = updateNode)
+
+    def draw_buttons(self, context, layout):
+        layout.prop(self, 'mode', text='')
+        layout.prop(self, 'if_possible')
+
+    def sv_init(self, context):
+        self.inputs.new('SvCurveSocket', "Curve")
+        self.inputs.new('SvStringsSocket', 'Degree').prop_name = 'degree'
+        self.inputs.new('SvStringsSocket', 'Tolerance').prop_name = 'tolerance'
+        self.outputs.new('SvCurveSocket', 'Curve')
+        self.outputs.new('SvStringsSocket', 'Error')
+
+    def process(self):
+        if not any(socket.is_linked for socket in self.outputs):
+            return
+
+        curve_s = self.inputs['Curve'].sv_get()
+        degree_s = self.inputs['Degree'].sv_get()
+        tolerance_s = self.inputs['Tolerance'].sv_get()
+
+        input_level = get_data_nesting_level(curve_s, data_types=(SvCurve,))
+        flat_output = input_level < 2
+        curve_s = ensure_nesting_level(curve_s, 2, data_types=(SvCurve,))
+        degree_s = ensure_nesting_level(degree_s, 2)
+        tolerance_s = ensure_nesting_level(tolerance_s, 2)
+
+        curves_out = []
+        error_out = []
+        for params in zip_long_repeat(curve_s, degree_s, tolerance_s):
+            new_curves = []
+            new_errors = []
+            for curve, degree, tolerance in zip_long_repeat(*params):
+                curve = SvNurbsCurve.to_nurbs(curve)
+                if curve is None:
+                    raise Exception("One of curves is not NURBS")
+                if self.mode == 'DELTA':
+                    kwargs = dict(delta = degree)
+                else:
+                    kwargs = dict(target = degree)
+                curve, error = curve.reduce_degree(tolerance=tolerance, return_error=True, if_possible = self.if_possible, **kwargs)
+                new_curves.append(curve)
+                new_errors.append(error)
+            if flat_output:
+                curves_out.extend(new_curves)
+                error_out.extend(new_errors)
+            else:
+                curves_out.append(new_curves)
+                error_out.append(new_errors)
+
+        self.outputs['Curve'].sv_set(curves_out)
+        self.outputs['Error'].sv_set(error_out)
+
+def register():
+    bpy.utils.register_class(SvCurveReduceDegreeNode)
+
+def unregister():
+    bpy.utils.unregister_class(SvCurveReduceDegreeNode)
+
--- a/utils/curve/nurbs.py
+++ b/utils/curve/nurbs.py
@@ -420,6 +420,7 @@ class SvNurbsCurve(SvCurve):
                result = reduced_segments[0]
                for segment in reduced_segments[1:]:
                    result = result.concatenate(segment, remove_knots=True, tolerance=tolerance)
+                    max_error = max(max_error, tolerance)
                result = result.reparametrize(src_t_min, src_t_max)
                return result, max_error, True