def _get_target_rectangle(left_top_pos, w, h):
    """根据左上角点和宽高求出目标区域."""
    x_min, y_min = left_top_pos
    x_middle, y_middle = int(x_min + w / 2), int(y_min + h / 2)
    left_bottom_pos, right_bottom_pos = (x_min, y_min + h), (x_min + w, 
        y_min + h)
    right_top_pos = x_min + w, y_min
    middle_point = x_middle, y_middle
    rectangle = left_top_pos, left_bottom_pos, right_bottom_pos, right_top_pos
    return middle_point, rectangle
