def _cropper(base, v_prop, h_prop):
    """

    Crops an image horizontally and vertically.

    Notes:

        - increasing ``h_prop`` increases the amount of the image's left side removed.

        - increasing ``v_prop`` increases the amount of the lower part of the image removed.

    :param base: an image represented as a 2D array.
    :type base: ``2D ndarray``
    :param v_prop: the proportion of the image to remove with respect to its height.
    :type v_prop: ``float``
    :param h_prop: the proportion of the image to remove with respect to its width.
    :type h_prop: ``float``
    :return: a cropped image as a 2D array
    :rtype: ``2D ndarray``
    """
    hcrop_base = base[:, int(base.shape[1] * h_prop):]
    return hcrop_base[:int(base.shape[0] * v_prop)]
