Add a ReverseCoords wrapper seed policy.

PiperOrigin-RevId: 636591381

ffn/inference/seed.py

@@ -198,12 +198,8 @@ class PolicyPeaks2d(BaseSeedPolicy):
   and peak finding to identify seed points.
   """
 
-  def __init__(self,
-               canvas,
-               min_distance=7,
-               threshold_abs=2.5,
-               sort_cmp='ascending',
-               **kwargs):
+  def __init__(self, canvas, min_distance=7, threshold_abs=2.5,
+               sort_cmp='ascending', **kwargs):
     """Initialize settings.
 
     For compatibility with original version, min_distance=3, threshold_abs=0,
@@ -420,9 +416,9 @@ def init_coords(self):
 
 
 class PolicyInvertOrigins(BaseSeedPolicy):
+  """Reverse order of the seed locations used in a previous segmentation run."""
 
-  def __init__(self, canvas, corner=None, segmentation_dir=None,
-               **kwargs):
+  def __init__(self, canvas, corner=None, segmentation_dir=None, **kwargs):
     super().__init__(canvas, **kwargs)
     self.corner = corner
     self.segmentation_dir = segmentation_dir
@@ -436,19 +432,55 @@ def init_coords(self):
                             in points])
 
 
+class PolicyDenseSeeds(BaseSeedPolicy):
+  """Dense seeds from thresholded image after optional erosion."""
+
+  def __init__(self, canvas: Any, threshold: float = 0.5, num_erosions: int = 0,
+               invert: bool = False, **kwargs):
+    super().__init__(canvas, **kwargs)
+    self._threshold = threshold
+    self._num_erosions = num_erosions
+    self._invert = invert
+
+  def init_coords(self):
+    img = self.canvas.image
+
+    x = np.array(img > self._threshold).astype(bool)
+    if self._invert:
+      x = ~x
+    for _ in range(self._num_erosions):
+      x = skimage.morphology.binary_erosion(x)
+    coords = np.where(x)
+
+    self.coords = np.array(coords).T
+
+
+class ReverseCoords(BaseSeedPolicy):
+  """Wraps another policy and just reverses the seed order."""
+
+  def __init__(self, canvas, policy_to_reverse: str, **policy_kwargs):
+    super().__init__(canvas)
+    policy_cls = globals()[policy_to_reverse]
+    self._policy = policy_cls(canvas, **policy_kwargs)
+
+  def init_coords(self):
+    self.coords = np.array(list(self._policy)[::-1])
+
+
 class SequentialPolicies(BaseSeedPolicy):
   """Applies policies sequentially."""
 
   def __init__(self, canvas, policies: Sequence[tuple[str, dict[str, Any]]],
-               **unused_kwargs):
+               **kwargs):
     """Initializes the policies.
 
     Args:
       canvas: inference Canvas object
       policies: sequence of policies to chain together. Each entry is a tuple
         of size two; the name of the policy, followed by a keyword dict.
-      **unused_kwargs: other keyword arguments.
+      **kwargs: other keyword arguments.
     """
+    del kwargs
     super().__init__(canvas)
     self._policies = []
     for seed_policy, seed_policy_kwargs in policies:
@@ -473,26 +505,3 @@ def get_state(self, previous=False):
   def set_state(self, state):
     for s, policy in zip(state, self._policies):
       policy.set_state(s)
-
-
-class PolicyDenseSeeds(BaseSeedPolicy):
-  """Dense seeds from thresholded image after optional erosion."""
-
-  def __init__(self, canvas: Any, threshold: float = 0.5, num_erosions: int = 0,
-               invert: bool = False, **kwargs):
-    super().__init__(canvas, **kwargs)
-    self._threshold = threshold
-    self._num_erosions = num_erosions
-    self._invert = invert
-
-  def init_coords(self):
-    img = self.canvas.image
-
-    x = np.array(img > self._threshold).astype(bool)
-    if self._invert:
-      x = ~x
-    for _ in range(self._num_erosions):
-      x = skimage.morphology.binary_erosion(x)
-    coords = np.where(x)
-
-    self.coords = np.array(coords).T