def rasterize_polygons_within_box(
    polygons: List[np.ndarray], box: np.ndarray, mask_size: int
) -> torch.Tensor:
    """
    Rasterize the polygons into a mask image and
    crop the mask content in the given box.
    The cropped mask is resized to (mask_size, mask_size).

    This function is used when generating training targets for mask head in Mask R-CNN.
    Given original ground-truth masks for an image, new ground-truth mask
    training targets in the size of `mask_size x mask_size`
    must be provided for each predicted box. This function will be called to
    produce such targets.

    Args:
        polygons (list[ndarray[float]]): a list of polygons, which represents an instance.
        box: 4-element numpy array
        mask_size (int):

    Returns:
        Tensor: BoolTensor of shape (mask_size, mask_size)
    """
    # 1. Shift the polygons w.r.t the boxes
    w, h = box[2] - box[0], box[3] - box[1]

    polygons = copy.deepcopy(polygons)
    for p in polygons:
        p[0::2] = p[0::2] - box[0]
        p[1::2] = p[1::2] - box[1]

    # 2. Rescale the polygons to the new box size
    # max() to avoid division by small number
    ratio_h = mask_size / max(h, 0.1)
    ratio_w = mask_size / max(w, 0.1)

    if ratio_h == ratio_w:
        for p in polygons:
            p *= ratio_h
    else:
        for p in polygons:
            p[0::2] *= ratio_w
            p[1::2] *= ratio_h

    # 3. Rasterize the polygons with coco api
    mask = polygons_to_bitmask(polygons, mask_size, mask_size)
    mask = torch.from_numpy(mask)
    return mask

    Rasterize the polygons into a mask image and
    crop the mask content in the given box.
    The cropped mask is resized to (mask_size, mask_size).

    This function is used when generating training targets for mask head in Mask R-CNN.
    Given original ground-truth masks for an image, new ground-truth mask
    training targets in the size of `mask_size x mask_size`
    must be provided for each predicted box. This function will be called to
    produce such targets.

    Args:
        polygons (list[ndarray[float]]): a list of polygons, which represents an instance.
        box: 4-element numpy array
        mask_size (int):

    Returns:
        Tensor: BoolTensor of shape (mask_size, mask_size)
    
EVA-01/det/detectron2/structures/masks.py