fix(polygon): Add a method to snap Polygon2D to a grid

ladybug_geometry/geometry2d/polygon.py

@@ -1150,6 +1150,25 @@ def snap_to_polygon(self, polygon, tolerance):
                     new_verts.append(pt)
         return Polygon2D(new_verts)
 
+    def snap_to_grid(self, grid_increment):
+        """Snap this polygon's vertices to the nearest grid node defined by an increment.
+
+        Args:
+            grid_increment: A positive number for dimension of each grid cell. This
+                typically should be equal to the tolerance or larger but should
+                not be larger than the smallest detail of the polygon that you
+                wish to resolve.
+
+        Returns:
+            A version of this polygon that is snapped to the grid.
+        """
+        new_verts = []
+        for pt in self.vertices:
+            new_x = grid_increment * round(pt.x / grid_increment)
+            new_y = grid_increment * round(pt.y / grid_increment)
+            new_verts.append(Point2D(new_x, new_y))
+        return Polygon2D(new_verts)
+
     def to_dict(self):
         """Get Polygon2D as a dictionary."""
         return {'type': 'Polygon2D',

tests/polygon2d_test.py

@@ -721,6 +721,19 @@ def test_distance_to_point():
     assert polygon.distance_from_edge_to_point(Point2D(1, 1)) != 0
 
 
+def test_snap_to_grid():
+    """Test the snap_to_grid method."""
+    pts = (Point2D(0.2, 0), Point2D(4.1, 0), Point2D(4.1, 4), Point2D(0, 4.2))
+    snapped_pts = (Point2D(0, 0), Point2D(4, 0), Point2D(4, 4), Point2D(0, 4))
+    polygon = Polygon2D(pts)
+
+    new_poly = polygon.snap_to_grid(0.5)
+    assert new_poly.vertices == snapped_pts
+
+    new_poly = polygon.snap_to_grid(0.01)
+    assert new_poly.vertices == pts
+
+
 def test_intersect_segments():
     """Tests that polygons within tolerance distance have vertices updated."""
     tolerance = 0.02