Tria updates

lapy/polygon.py

@@ -5,6 +5,7 @@
 """
 import logging
 import sys
+from typing import Optional
 
 import numpy as np
 from scipy import sparse
@@ -22,15 +23,21 @@ class Polygon:
     points : np.ndarray
         Array of shape (n, d) containing coordinates of polygon vertices
         in order, where d is 2 or 3 for 2D (x, y) or 3D (x, y, z) paths.
-        For closed polygons, the last point should not duplicate the first point.
-    closed : bool, default=False
-        If True, treats the path as a closed polygon. If False, treats it as
-        an open polyline.
+        If the last point duplicates the first point and closed is None,
+        the duplicate endpoint will be removed and the polygon will be
+        marked as closed automatically.
+    closed : bool or None, default=None
+        - If None (default): Auto-detect by checking if first and last points
+          are identical. If they are, removes duplicate endpoint and sets closed=True.
+        - If True: Treats the path as a closed polygon. If the last point duplicates
+          the first, it will be removed.
+        - If False: Treats the path as an open polyline regardless of endpoints.
 
     Attributes
     ----------
     points : np.ndarray
-        Polygon vertex coordinates, shape (n_points, d).
+        Polygon vertex coordinates, shape (n_points, d). For closed polygons,
+        the last point does not duplicate the first.
     closed : bool
         Whether the polygon is closed or open.
     _is_2d : bool
@@ -46,23 +53,22 @@ class Polygon:
     --------
     >>> import numpy as np
     >>> from lapy.polygon import Polygon
-    >>> # Create a 2D closed polygon (square)
-    >>> square = np.array([[0, 0], [1, 0], [1, 1], [0, 1]])
-    >>> poly = Polygon(square, closed=True)
-    >>> poly.is_2d()
+    >>> # Create a 2D closed polygon (square) - auto-detected
+    >>> square = np.array([[0, 0], [1, 0], [1, 1], [0, 1], [0, 0]])
+    >>> poly = Polygon(square)  # closed=None, will auto-detect and remove duplicate
+    >>> poly.closed
     True
-    >>> poly.length()
-    4.0
-    >>> # Create a 3D open path
-    >>> path_3d = np.array([[0, 0, 0], [1, 0, 0], [1, 1, 0], [1, 1, 1]])
-    >>> poly3d = Polygon(path_3d, closed=False)
-    >>> poly3d.is_2d()
+    >>> poly.points.shape[0]
+    4
+    >>> # Explicitly open polygon
+    >>> path = np.array([[0, 0, 0], [1, 0, 0], [1, 1, 0], [1, 1, 1]])
+    >>> poly3d = Polygon(path, closed=False)
+    >>> poly3d.closed
     False
     """
 
-    def __init__(self, points: np.ndarray, closed: bool = False):
+    def __init__(self, points: np.ndarray, closed: Optional[bool] = None):
         self.points = np.array(points)
-        self.closed = closed
 
         # Validate non-empty polygon
         if self.points.size == 0:
@@ -93,6 +99,25 @@ def __init__(self, points: np.ndarray, closed: bool = False):
         else:
             raise ValueError("Points should have 2 or 3 coordinates")
 
+        # Auto-detect closed polygons or handle explicit closed parameter
+        if closed is None:
+            # Auto-detect: check if first and last points are identical
+            if len(self.points) > 1 and np.allclose(self.points[0], self.points[-1]):
+                # Remove duplicate endpoint
+                self.points = self.points[:-1]
+                self.closed = True
+            else:
+                # Not closed (endpoints differ)
+                self.closed = False
+        elif closed:
+            # Explicitly closed: remove duplicate endpoint if present
+            if len(self.points) > 1 and np.allclose(self.points[0], self.points[-1]):
+                self.points = self.points[:-1]
+            self.closed = True
+        else:
+            # Explicitly open
+            self.closed = False
+
     def is_2d(self) -> bool:
         """Check if the polygon is 2D.