Refactor a utility function for bbox conversion

Summary: This function makes it easier to extend FrameData class with new channels; brushing it up a bit.

Reviewed By: bottler

Differential Revision: D67816470

fbshipit-source-id: 6575415c864d0f539e283889760cd2331bf226a7

Author: shapovalov

pytorch3d/implicitron/dataset/utils.py

@@ -134,7 +134,15 @@ def clamp_box_to_image_bounds_and_round(
 def bbox_xyxy_to_xywh(xyxy: T) -> T:
     wh = xyxy[2:] - xyxy[:2]
     xywh = torch.cat([xyxy[:2], wh])
-    return xywh  # pyre-ignore
+    return xywh  # pyre-ignore[7]
+
+
+def bbox_xywh_to_xyxy(xywh: T, clamp_size: float | int | None = None) -> T:
+    wh = xywh[2:]
+    if clamp_size is not None:
+        wh = wh.clamp(min=clamp_size)
+    xyxy = torch.cat([xywh[:2], xywh[:2] + wh])
+    return xyxy  # pyre-ignore[7]
 
 
 def get_clamp_bbox(
@@ -180,16 +188,6 @@ def rescale_bbox(
     return bbox * rel_size
 
 
-def bbox_xywh_to_xyxy(
-    xywh: torch.Tensor, clamp_size: Optional[int] = None
-) -> torch.Tensor:
-    xyxy = xywh.clone()
-    if clamp_size is not None:
-        xyxy[2:] = torch.clamp(xyxy[2:], clamp_size)
-    xyxy[2:] += xyxy[:2]
-    return xyxy
-
-
 def get_1d_bounds(arr: np.ndarray) -> Tuple[int, int]:
     nz = np.flatnonzero(arr)
     return nz[0], nz[-1] + 1