def get_face_size(bbox, width, height):
    """
    Compute the face size in pixel coordinates.
    """

    x1 = int(bbox[0] * width)
    y1 = int(bbox[1] * height)
    x2 = int(bbox[2] * width)
    y2 = int(bbox[3] * height)
    width = x2 - x1
    height = y2 - y1
    return width, height