Merge branch 'add_get_min_max_to_vol' into '1.0'

volume: add get_min_max function

See merge request !119

tomoscan/esrf/volume/test/test_hdf5volume.py

@@ -184,6 +184,11 @@ def test_hdf5volume_file_path(tmp_path):
     # test hash
     hash(volume_from_str)
 
+    # test get_min_max values
+    assert volume_from_str.get_min_max() == (_data.min(), _data.max())
+    volume_from_str.load_data()
+    assert volume_from_str.get_min_max() == (_data.min(), _data.max())
+
 
 def test_hdf5volume_data_url_and_metadata_url(tmp_path):
     """test creation of an hdf5volume by providing a data url and a metadata url"""

tomoscan/esrf/volume/test/test_single_frame_volume.py

@@ -171,6 +171,12 @@ def test_create_volume_from_folder(tmp_path, volume_constructor):
     for l_frame, o_frame in zip(volume.browse_slices(), _data):
         numpy.testing.assert_allclose(l_frame, o_frame)
 
+    # test get_min_max values
+    volume.data = None
+    assert volume.get_min_max() == (_data.min(), _data.max())
+    volume.load_data()
+    assert volume.get_min_max() == (_data.min(), _data.max())
+
 
 @pytest.mark.parametrize("volume_constructor", volume_constructors)
 def test_data_file_saver_generator(tmp_path, volume_constructor):

tomoscan/volumebase.py

@@ -238,6 +238,19 @@ class VolumeBase(TomoObject):
     def dims_in_cm(self):
         raise NotImplementedError("Base class")
 
+    def get_min_max(self) -> tuple:
+        """
+        compute min max of the volume. Can take some time but avoid to load the full volume in memory
+        """
+        if self.data is not None:
+            return self.data.min(), self.data.max()
+        else:
+            min_v, max_v = None, None
+            for s in self.browse_slices():
+                min_v = min(min_v, s.min()) if min_v is not None else s.min()
+                max_v = max(max_v, s.max()) if max_v is not None else s.max()
+            return min_v, max_v
+
     # load / save stuff
 
     @property