C# 给url获取图片添加文字水印

qq_40099034

已于 2022-11-29 18:09:39 修改

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分类专栏： C# 文章标签： c# 开发语言

于 2022-11-29 18:02:00 首次发布

本文链接：https://blog.youkuaiyun.com/qq_40099034/article/details/128102551

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这个博客介绍了一种在C#中通过HTTP请求获取远程图片，并添加水印后保存到本地的方法。主要涉及了`GetBytesFromUrl`用于从URL获取图片字节流，`WriteBytesToFileWaterMark`方法用于在图片上添加水印并保存，使用了Graphics类进行绘制操作。

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参考地址：https://bbs.youkuaiyun.com/topics/390695085?list=lz

调用方法

 WriteBytesToFileWaterMark("文件地址+图片名称", GetBytesFromUrl("网络图片URL"), "水印内容");
 //例
  WriteBytesToFileWaterMark("E:\2.png", GetBytesFromUrl("https://cube.elemecdn.com/6/94/4d3ea53c084bad6931a56d5158a48jpeg.jpeg"), "水印内容");

添加水印方法

 /// <summary>
        /// 通过url获取到图片
        /// </summary>
        /// <param name="url"></param>
        /// <returns></returns>
        public static byte[] GetBytesFromUrl(string url)
        {
            
            try
            {
                byte[] b;
                HttpWebRequest myReq = (HttpWebRequest)WebRequest.Create(url);
                WebResponse myResp = myReq.GetResponse();
                Stream stream = myResp.GetResponseStream();
                using (BinaryReader br = new BinaryReader(stream))
                {
                    b = br.ReadBytes((int)myResp.ContentLength);
                    br.Close();
                }
                myResp.Close();
                return b;
            }
            catch (Exception e)
            {
                byte[] b = new byte[0] { };
              
                return b;
            }

           

        }

        /// <summary>
        /// 保存图片
        /// </summary>
        /// <param name="fileName"></param>
        /// <param name="content"></param>
        public static void WriteBytesToFile(string fileName, byte[] content)
        {
            try
            {
                FileStream fs = new FileStream(fileName, FileMode.Create);
                BinaryWriter w = new BinaryWriter(fs);
                try
                {
                    w.Write(content);
                }
                finally
                {
                    fs.Close();
                    w.Close();
                }
            }
            catch (Exception e)
            { 	
            	Console.WriteLine(e);
            }

        }
        
   		/// <summary>
        /// 保存水印图片
        /// </summary>
        /// <param name="fileName">地址+文件名称</param>
        /// <param name="content">图片流</param>
        /// <param name="watermark">水印文字</param>
        public static void WriteBytesToFileWaterMark(string fileName, byte[] content, string watermark)
        {
            try
            {
                
                FileStream fs = new FileStream(fileName, FileMode.Create);
                BinaryWriter w = new BinaryWriter(fs);
                try
                {
                    Byte[] photo = content;
                    MemoryStream stmBLOB = new MemoryStream(photo);
                    Image pic = Image.FromStream(stmBLOB);

                    Graphics grap = Graphics.FromImage(pic);
                    Brush brush = new SolidBrush(Color.Red);//创建一把刷子
                    int xpos = 10;
                    int ypos = 10;
                    
                    grap.DrawString(watermark, new Font("宋体", 80), brush, xpos, ypos);//给图片(pic)加水印,(水印文字，

                    grap.Dispose();

                    var filenameImg = "13.png";
                    pic.Save(filenameImg, System.Drawing.Imaging.ImageFormat.Jpeg);
                    
                    byte[] img=PhotoImageInsert(pic);
                   
                    w.Write(img);
                    pic.Dispose();
                }
                finally
                {
                    fs.Close();
                    w.Close();
                }
            }
            catch (Exception e)
            {
             	Console.WriteLine(e);
            }

        }

        /// <summary>
        /// 将Image转换成流数据，并保存为byte[] 
        /// </summary>
        /// <param name="imgPhoto"></param>
        /// <returns></returns>
        public static byte[] PhotoImageInsert(System.Drawing.Image imgPhoto)
        {
            try
            {
                MemoryStream mstream = new MemoryStream();
                imgPhoto.Save(mstream, System.Drawing.Imaging.ImageFormat.Bmp);
                byte[] byData = new Byte[mstream.Length];
                mstream.Position = 0;
                mstream.Read(byData, 0, byData.Length); mstream.Close();
                return byData;
            }
            catch (Exception e)
            {
                Console.WriteLine(e);

                byte[] ret = new byte[1];
                return ret;
            }
           
        }