Catch and fix cases where incoming label matrix is not sequential.

ncolor/format_labels.py

@@ -9,6 +9,9 @@
     SKIMAGE_ENABLED = True 
 except:
     SKIMAGE_ENABLED = False
+
+def is_sequential(labels):
+        return np.all(np.diff(fastremap.unique(labels))==1)
 
 def format_labels(labels, clean=False, min_area=9, despur=False, verbose=False, ignore=False):
     """

ncolor/label.py

@@ -2,13 +2,16 @@
 
 import numpy as np
 from numba import njit
-import scipy 
-from .format_labels import format_labels
+import scipy
+from .format_labels import format_labels, is_sequential
 
 def label(lab, n=4, conn=2, max_depth=5, offset=0):
     # needs to be in standard label form
     # but also needs to be in int32 data type to work properly; the formatting automatically
     # puts it into the smallest datatype to save space 
+    if not is_sequential(lab):
+        lab = format_labels(lab)
+
     lut = get_lut(lab,n,conn,max_depth,offset)
     return lut[lab]
 

setup.py

@@ -1,7 +1,7 @@
 import setuptools
 from setuptools import setup
 
-install_deps = ['numpy>=1.22.0', 'scipy', 'numba', 
+install_deps = ['numpy>=1.22.4', 'scipy', 'numba', 
                 'fastremap','scikit-image','mahotas==1.4.12']
 
 with open("README.md", "r") as fh: