def resize()

in lucid/misc/ndimage_utils.py [0:0]

• 27 lines of code
• 12 McCabe index (conditional complexity)

def resize(image, target_size=None, ratios=None, **kwargs):
    """Resize an ndarray image of rank 3 or 4.
    target_size can be a tuple `(width, height)` or scalar `width`.
    Alternatively you can directly specify the ratios by which each
    dimension should be scaled, or a single ratio"""

    # input validation
    if target_size is None:
      assert ratios is not None
    else:
      if isinstance(target_size, int):
          target_size = (target_size, target_size)

      if not isinstance(target_size, (list, tuple, np.ndarray)):
          message = (
              "`target_size` should be a single number (width) or a list"
              "/tuple/ndarray (width, height), not {}.".format(type(target_size))
          )
          raise ValueError(message)

    rank = len(image.shape)
    assert 3 <= rank <= 4

    original_size = image.shape[-3:-1]


    ratios_are_noop = all(ratio == 1 for ratio in ratios) if ratios is not None else False
    target_size_is_noop = target_size == original_size if target_size is not None else False
    if ratios_are_noop or target_size_is_noop:
        return image  # noop return because ndimage.zoom doesn't check itself

    # TODO: maybe allow -1 in target_size to signify aspect-ratio preserving resize?
    ratios = ratios or [t / o for t, o in zip(target_size, original_size)]
    zoom = [1] * rank
    zoom[-3:-1] = ratios

    roughly_resized = ndimage.zoom(image, zoom, **kwargs)
    if target_size is not None:
      return roughly_resized[..., : target_size[0], : target_size[1], :]
    else:
      return roughly_resized