BUG: Add bufferedRegion to dict_from_image representation

Optional specification of the BufferedRegion, which is a subset of the
LargestPossibleRegion. Addresses #4267.

The LargestPossibleRegion's Index is assumed to be trivial (zeros).

Also update the NumPy bridge to correctly use the BufferedRegion instead
of the LargestPossibleRegion for the array shape.

Author: thewtex

Modules/Bridge/NumPy/wrapping/PyBuffer.i.in

@@ -20,7 +20,7 @@
             if source:
                 source.UpdateLargestPossibleRegion()
 
-        itksize = image.GetLargestPossibleRegion().GetSize()
+        itksize = image.GetBufferedRegion().GetSize()
         dim     = len(itksize)
         shape   = [int(itksize[idx]) for idx in range(dim)]
 

Wrapping/Generators/Python/Tests/extras.py

@@ -224,6 +224,14 @@ def custom_callback(name, progress):
 diff = itk.comparison_image_filter(image.astype(itk.F), image_back.astype(itk.F))
 assert np.sum(diff) == 0
 
+
+largest_region = itk.ImageRegion[2]([0, 0], [1024, 1024])
+image.SetLargestPossibleRegion(largest_region)
+image_dict = itk.dict_from_image(image)
+image_back = itk.image_from_dict(image_dict)
+diff = itk.comparison_image_filter(image.astype(itk.F), image_back.astype(itk.F))
+assert np.sum(diff) == 0
+
 mesh_dict = itk.dict_from_mesh(mesh)
 mesh_back = itk.mesh_from_dict(mesh_dict)
 

Wrapping/Generators/Python/itk/support/extras.py

@@ -789,12 +789,15 @@ def dict_from_image(image: "itkt.Image") -> Dict:
 
     pixel_arr = itk.array_from_image(image)
     imageType = wasm_type_from_image_type(image)
+    buffered_region = image.GetBufferedRegion()
+    bufferedRegion = { "index": tuple(buffered_region.GetIndex()), "size": tuple(buffered_region.GetSize())}
     return dict(
         imageType=imageType,
         name=image.GetObjectName(),
         origin=tuple(image.GetOrigin()),
         spacing=tuple(image.GetSpacing()),
-        size=tuple(image.GetBufferedRegion().GetSize()),
+        size=tuple(image.GetLargestPossibleRegion().GetSize()),
+        bufferedRegion=bufferedRegion,
         direction=np.asarray(image.GetDirection()),
         data=pixel_arr,
     )
@@ -808,10 +811,20 @@ def image_from_dict(image_dict: Dict) -> "itkt.Image":
     if image_dict["data"] is None:
         image = ImageType.New()
         image.SetRegions(image_dict["size"])
+        if "bufferedRegion" in image_dict:
+            buffered_region = itk.ImageRegion[image.GetImageDimension()]()
+            buffered_region.SetIndex(image_dict["bufferedRegion"]["index"])
+            buffered_region.SetSize(image_dict["bufferedRegion"]["size"])
+            image.SetBufferedRegion(buffered_region)
         image.Allocate(True)
     else:
         image = itk.PyBuffer[ImageType].GetImageViewFromArray(image_dict["data"])
         image.SetRegions(image_dict["size"])
+        if "bufferedRegion" in image_dict:
+            buffered_region = itk.ImageRegion[image.GetImageDimension()]()
+            buffered_region.SetIndex(image_dict["bufferedRegion"]["index"])
+            buffered_region.SetSize(image_dict["bufferedRegion"]["size"])
+            image.SetBufferedRegion(buffered_region)
     image.SetOrigin(image_dict["origin"])
     image.SetSpacing(image_dict["spacing"])
     image.SetDirection(image_dict["direction"])