Fix issues with `get_image_size()` (#6581)

* Fix bug on `get_image_size()` and move it to deprecated. Introduce generic named spatial/channel equivalents.

* Update tests and fix mypy issues.

* Remove the use of get_image_size from ElasticTransform.

* Fix linter

* Apply suggestions from code review.

* Update torchvision/prototype/transforms/functional/_deprecated.py
Co-authored-by: Philip Meier <github.pmeier@posteo.de>

* Further changes from code review.

* Fix linter
Co-authored-by: Philip Meier <github.pmeier@posteo.de>

test/test_prototype_transforms_functional.py

@@ -531,6 +531,8 @@ def erase_image_tensor():
         and name
         not in {
             "to_image_tensor",
+            "get_num_channels",
+            "get_spatial_size",
             "get_image_num_channels",
             "get_image_size",
         }

torchvision/prototype/transforms/functional/__init__.py

@@ -9,7 +9,8 @@ from ._meta import (
     convert_color_space,
     get_dimensions,
     get_image_num_channels,
-    get_image_size,
+    get_num_channels,
+    get_spatial_size,
 )  # usort: skip
 
 from ._augment import erase, erase_image_pil, erase_image_tensor
@@ -125,4 +126,4 @@ from ._type_conversion import (
     to_pil_image,
 )
 
-from ._deprecated import rgb_to_grayscale, to_grayscale  # usort: skip
+from ._deprecated import get_image_size, rgb_to_grayscale, to_grayscale, to_tensor  # usort: skip

torchvision/prototype/transforms/functional/_deprecated.py

 import warnings
-from typing import Any, Union
+from typing import Any, List, Union
 
 import PIL.Image
 import torch
@@ -50,3 +50,11 @@ def to_tensor(inpt: Any) -> torch.Tensor:
         "Instead, please use `to_image_tensor(...)` followed by `convert_image_dtype(...)`."
     )
     return _F.to_tensor(inpt)
+
+
+def get_image_size(inpt: Union[PIL.Image.Image, torch.Tensor, features.Image]) -> List[int]:
+    warnings.warn(
+        "The function `get_image_size(...)` is deprecated and will be removed in a future release. "
+        "Instead, please use `get_spatial_size(...)` which returns `[h, w]` instead of `[w, h]`."
+    )
+    return _F.get_image_size(inpt)

torchvision/prototype/transforms/functional/_meta.py

@@ -34,14 +34,19 @@ def get_dimensions(image: Union[PIL.Image.Image, torch.Tensor, features.Image])
     return list(get_chw(image))
 
 
-def get_image_num_channels(image: Union[PIL.Image.Image, torch.Tensor, features.Image]) -> int:
+def get_num_channels(image: Union[PIL.Image.Image, torch.Tensor, features.Image]) -> int:
     num_channels, *_ = get_chw(image)
     return num_channels
 
 
-def get_image_size(image: Union[PIL.Image.Image, torch.Tensor, features.Image]) -> List[int]:
-    _, *image_size = get_chw(image)
-    return image_size
+# We changed the names to ensure it can be used not only for images but also videos. Thus, we just alias it without
+# deprecating the old names.
+get_image_num_channels = get_num_channels
+
+
+def get_spatial_size(image: Union[PIL.Image.Image, torch.Tensor, features.Image]) -> List[int]:
+    _, *size = get_chw(image)
+    return size
 
 
 def _xywh_to_xyxy(xywh: torch.Tensor) -> torch.Tensor:

torchvision/transforms/transforms.py

@@ -2162,8 +2162,8 @@ class ElasticTransform(torch.nn.Module):
         Returns:
             PIL Image or Tensor: Transformed image.
         """
-        size = F.get_image_size(tensor)[::-1]
-        displacement = self.get_params(self.alpha, self.sigma, size)
+        _, height, width = F.get_dimensions(tensor)
+        displacement = self.get_params(self.alpha, self.sigma, [height, width])
         return F.elastic_transform(tensor, displacement, self.interpolation, self.fill)
 
     def __repr__(self):