uni-app在app端使用uview上传文件并添加水印，踩坑
1.返回的文件是临时路径的:参考这个https://blog.csdn.net/sansanyuner/article/details/114384318
2.添加水印需要设置延时，不然图片会出现空白的情况参考这两个
https://blog.csdn.net/weixin_39764603/article/details/112930145
https://blog.csdn.net/ypf_1996/article/details/123105983?spm=1001.2101.3001.6661.1&utm_medium=distribute.pc_relevant_t0.none-task-blog-2%7Edefault%7ECTRLIST%7ERate-1-123105983-blog-122583308.pc_relevant_multi_platform_whitelistv3&depth_1-utm_source=distribute.pc_relevant_t0.none-task-blog-2%7Edefault%7ECTRLIST%7ERate-1-123105983-blog-122583308.pc_relevant_multi_platform_whitelistv3&utm_relevant_index=1