fix: support raster labels above uint16

src/spatialdata/_core/operations/rasterize.py

@@ -30,7 +30,7 @@
     get_axes_names,
     get_model,
 )
-from spatialdata.models._utils import get_spatial_axes
+from spatialdata.models._utils import _get_uint_dtype, get_spatial_axes
 from spatialdata.transformations._utils import _get_scale, compute_coordinates
 from spatialdata.transformations.operations import get_transformation, remove_transformation, set_transformation
 from spatialdata.transformations.transformations import (
@@ -733,10 +733,7 @@ def rasterize_shapes_points(
             max_label = next(iter(reversed(label_index_to_category.keys())))
         else:
             max_label = int(agg.max().values)
-        max_uint16 = np.iinfo(np.uint16).max
-        if max_label > max_uint16:
-            raise ValueError(f"Maximum label index is {max_label}. Values higher than {max_uint16} are not supported.")
-        agg = agg.astype(np.uint16)
+        agg = agg.astype(_get_uint_dtype(max_label))
         return Labels2DModel.parse(agg, transformations=transformations)
 
     agg = agg.expand_dims(dim={"c": 1}).transpose("c", "y", "x")

tests/core/operations/test_rasterize.py

@@ -446,6 +446,29 @@ def _rasterize(element: DaskDataFrame, **kwargs) -> SpatialImage:
     assert d[res[1, 2]] == 4
 
 
+def test_rasterize_points_selects_label_dtype():
+    n_points = np.iinfo(np.uint16).max + 1
+    points = PointsModel.parse(
+        dd.from_pandas(
+            pd.DataFrame({"x": np.arange(n_points), "y": np.zeros(n_points)}),
+            npartitions=1,
+        )
+    )
+
+    result = rasterize(
+        points,
+        axes=("x", "y"),
+        min_coordinate=[0, 0],
+        max_coordinate=[n_points, 1],
+        target_coordinate_system="global",
+        target_width=n_points,
+        return_regions_as_labels=True,
+    )
+
+    assert result.dtype == np.uint32
+    assert result.max().compute() == n_points
+
+
 def test_rasterize_spatialdata(full_sdata):
     sdata = full_sdata.subset(
         ["image2d", "image2d_multiscale", "labels2d", "labels2d_multiscale", "points_0", "circles"]