Merge pull request #1180 from nmaslarinos/polyline_new_methods

Polyline new methods

Author: tomvanmele

CHANGELOG.md

@@ -118,6 +118,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Added `compas.geometry.Surface.point_at`.
 * Added `compas.geometry.Surface.normal_at`.
 * Added `compas.geometry.Surface.frame_at`.
+* Added `compas.geometry.Polyline.parameter_at`.
+* Added `compas.geometry.Polyline.divide_at_corners`.
 * Added `mesh_to_rhino` to `compas_rhino.conversions`.
 * Added `vertices_and_faces_to_rhino` to `compas_rhino.conversions`.
 * Added `polyhedron_to_rhino` to `compas_rhino.conversions`.
@@ -225,6 +227,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Changed `compas.datastructures.Graph.delete_edge` to delete invalid (u, u) edges and not delete edges in opposite directions (v, u)
 * Fixed bug in `compas.datastructures.Mesh.insert_vertex`.
 * Fixed bug in `compas.geometry.angle_vectors_signed`.
+* Fixed bug in `compas.geometry.Polyline.split_at_corners` where angles were sometimes wrongly calculated.
 * Changed `compas.artists.MeshArtist` default colors.
 * Changed internal _plane storage of the `compas.datastructures.Halfface` from `_plane[u][v][w]` to `_plane[u][v][fkey]`
 * Fixed `SyntaxError` when importing COMPAS in GHPython.

src/compas/geometry/curves/polyline.py

@@ -6,7 +6,7 @@
 
 from compas.geometry import allclose
 from compas.geometry import transform_points
-from compas.geometry import is_point_on_line
+from compas.geometry import is_point_on_line, is_point_on_polyline
 from compas.geometry import Point
 from compas.geometry import Line
 from compas.geometry import Frame
@@ -277,6 +277,40 @@ def point_at(self, t, snap=False):
             x += dx
             i += 1
 
+    def parameter_at(self, point, tol=1e-6):
+        """Parameter of the polyline at a specific point.
+
+        Parameters
+        ----------
+        point : [float, float, float] | :class:`~compas.geometry.Point`
+            The point on the polyline.
+        tol : float, optional
+            A tolerance for membership verification.
+
+        Returns
+        -------
+        float
+            The parameter of the polyline.
+
+        Examples
+        --------
+        >>> from compas.geometry import Point
+        >>> polyline = Polyline([[0.0, 0.0, 0.0], [1.0, 0.0, 0.0], [1.0, 1.0, 0.0]])
+        >>> polyline.parameter_at(Point(0.1, 0.0, 0.0))
+        0.5
+
+        """
+        if not is_point_on_polyline(point, self, tol):
+            raise Exception("{} not found!".format(point))
+        dx = 0
+        for line in self.lines:
+            if not is_point_on_line(point, line, tol):
+                dx += line.length
+                continue
+            dx += line.start.distance_to_point(point)
+            break
+        return dx / self.length
+
     def tangent_at(self, t):
         """Tangent vector at a specific normalized parameter.
 
@@ -358,7 +392,7 @@ def split_at_corners(self, angle_threshold):
             seg_ids.append(0)
 
         for seg1, seg2 in pairwise(seg_ids):
-            angle = self.lines[seg1].vector.angle(self.lines[seg2].vector)
+            angle = self.lines[seg2].vector.angle(-self.lines[seg1].vector)
             if angle >= angle_threshold:
                 corner_ids.append(seg1 + 1)
 
@@ -380,6 +414,30 @@ def split_at_corners(self, angle_threshold):
 
         return split_polylines
 
+    def divide_at_corners(self, angle_threshold):
+        """Divides a polyline at corners larger than the given angle_threshold
+
+        Parameters
+        ----------
+        angle_threshold : float
+            In radians.
+
+        Returns
+        -------
+        list[:class:`~compas.geometry.Point`]
+
+        """
+        corner_ids = []
+        seg_ids = list(range(len(self.lines)))
+        if self.is_closed:
+            seg_ids.insert(0, seg_ids[-1])
+
+        for seg1, seg2 in pairwise(seg_ids):
+            angle = self.lines[seg2].vector.angle(-self.lines[seg1].vector)
+            if angle >= angle_threshold:
+                corner_ids.append(seg1 + 1)
+        return [self.points[i] for i in corner_ids]
+
     def divide(self, num_segments):
         """Divide a polyline in equal segments.
 

tests/compas/geometry/test_curves_polyline.py

@@ -257,6 +257,24 @@ def test_polyline_split_at_corners(coords, input, expected):
     assert expected == Polyline(coords).split_at_corners(input)
 
 
+@pytest.mark.parametrize(
+    "input,expected",
+    [
+        (
+            math.radians(160),
+            [],
+        ),
+        (math.radians(100), [(1, 0, 0)]),
+        (math.radians(90), [(0, 0, 0), (1, 0, 0)]),
+        (math.radians(75), [(0, 0, 0), (1, 0, 0), (0, 1, 0)]),
+        (math.radians(44), [(0, 0, 0), (1, 0, 0), (1.86602540378444, 0.5, 0), (0, 1, 0)]),
+    ],
+)
+def test_polyline_divide_at_corners(input, expected):
+    polyline = Polyline(([0, 0, 0], [1, 0, 0], [1.86602540378444, 0.5, 0], [0, 1, 0], [0, 0, 0]))
+    assert expected == polyline.divide_at_corners(input)
+
+
 @pytest.mark.parametrize(
     "coords,segments_number,expected",
     [
@@ -431,6 +449,16 @@ def test_polyline_tangent_at_point(coords, input, expected):
     assert expected == Polyline(coords).tangent_at_point(input)
 
 
+@pytest.mark.parametrize("input,expected", [((0, 0, 0), 0.0), ((1, 0, 0), 0.5), ((1, 1, 0), 1.0), ((2, 0, 0), None)])
+def test_polyline_parameter_at(input, expected):
+    polyline = Polyline(((0, 0, 0), (1, 0, 0), (1, 1, 0)))
+    if expected is not None:
+        assert expected == polyline.parameter_at(input)
+    else:
+        with pytest.raises(Exception):
+            polyline.parameter_at(input)
+
+
 @pytest.mark.parametrize(
     "coords,input,expected",
     [