Add a factory method for OwnedImagePlanes

python/lsst/cell_coadds/_image_planes.py

@@ -29,12 +29,12 @@
 
 from abc import ABC, abstractmethod
 from collections.abc import Callable, Sequence
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Self
 
 from lsst.afw.image import MaskedImageF
 
 if TYPE_CHECKING:
-    from lsst.afw.image import Mask
+    from lsst.afw.image import Mask, MaskedImage
     from lsst.geom import Box2I
 
     from .typing_helpers import ImageLike
@@ -116,6 +116,22 @@ def __init__(
         self._mask_fractions = mask_fractions
         self._noise_realizations = tuple(noise_realizations)
 
+    @classmethod
+    def from_masked_image(
+        cls,
+        masked_image: MaskedImage,
+        mask_fractions: ImageLike | None = None,
+        noise_realizations: Sequence[ImageLike] = (),
+    ) -> Self:
+        """Construct from an `lsst.afw.image.MaskedImage`."""
+        return cls(
+            image=masked_image.image,
+            mask=masked_image.mask,
+            variance=masked_image.variance,
+            mask_fractions=mask_fractions,
+            noise_realizations=noise_realizations,
+        )
+
     @property
     def bbox(self) -> Box2I:
         # Docstring inherited.