def generate_colors(n_colors, seed=47):
    """
    隨機生成顏色
    """
    np.random.seed(seed)
    color_list = []
    for i in range(n_colors):
        color = (np.random.random((1, 3)) * 0.8).tolist()[0]
        color = [int(j * 255) for j in color]
        color_list.append(color)

    return color_list

def draw_mask_layers(image, mask_layers, mask_tk=1):
    """
    繪制多層的mask，包含mask的邊界，mask中不同值表示不同的instance
    :param image: 3通道圖像
    :param mask_layers: 多instance的mask
    :param mask_tk: 邊界的厚度
    :return: 繪制邊界框
    """
    img_copy = copy.copy(image)

    # 拆分Mask
    h, w = mask_layers.shape[:2]
    mask_id = np.unique(mask_layers)[1:]  # 獲取Mask的ID, 0是背景
    masks = []
    for i in mask_id:
        m = np.zeros((h, w), dtype=bool)
        m[mask_layers == i] = True
        masks.append(m)

    # 繪制顏色區(qū)域
    color_list = generate_colors(len(masks))
    for idx, mask in enumerate(masks):
        img_copy[mask] = color_list[idx]  # 繪制顏色框

    image = cv2.addWeighted(image, 0.5, img_copy, 0.5, 0)  # 合并mask

    # 繪制邊界，邊界不需要透視效果
    for idx, mask in enumerate(masks):
        cnt_mask = np.zeros((h, w))
        cnt_mask[mask] = 255
        cnt_mask = cnt_mask.astype(np.uint8)
        contours, _ = cv2.findContours(cnt_mask, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)
        cv2.drawContours(image, contours, -1, (255, 255, 255), mask_tk)  # 繪制白色邊界

    return image