Handle empty polygons in inflate_polygon (#328)

Author: sea-bass

pyrobosim/pyrobosim/utils/polygon.py

@@ -95,6 +95,8 @@ def inflate_polygon(poly, radius):
     inflated_poly = poly.buffer(
         radius, cap_style=CAP_STYLE.flat, join_style=JOIN_STYLE.mitre
     )
+    if inflated_poly.is_empty:
+        return inflated_poly
     return orient(inflated_poly)
 
 

pyrobosim/test/utils/test_polygon_utils.py

@@ -75,8 +75,13 @@ def test_get_polygon_centroid():
 
 
 def test_inflate_polygon():
+    empty_poly = Polygon()
     square_poly = Polygon(square_coords)
 
+    # Empty polygon
+    inflated_poly = inflate_polygon(empty_poly, 0.0)
+    assert inflated_poly == empty_poly
+
     # Zero inflation radius
     inflated_poly = inflate_polygon(square_poly, 0.0)
     inflated_poly_coords = list(inflated_poly.exterior.coords)
@@ -108,8 +113,13 @@ def test_inflate_polygon():
 
 
 def test_transform_polygon():
+    empty_poly = Polygon()
     square_poly = Polygon(box_to_coords(dims=[1.0, 2.0]))
 
+    # Empty polygon
+    transformed_poly = transform_polygon(empty_poly, None)
+    assert transformed_poly == empty_poly
+
     # No transformation, using None as pose
     transformed_poly = transform_polygon(square_poly, None)
     assert transformed_poly == square_poly