详细QRCode生成二维码和下载实现案例

 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Web;
 using ThoughtWorks.QRCode.Codec;
 using System.Drawing;
 using System.Drawing.Imaging;
 using Game.Utils;
 using System.Drawing.Drawing2D;
 using Game.Facade;
 using System.Net;
 using System.IO;

 namespace Game.Web.WS
 {
     /// <summary>
     /// QRCode 的摘要说明
     /// </summary>
     public class QRCode : IHttpHandler
     {

         public void ProcessRequest(HttpContext context)
         {
             GetQRCode(context);
         }

         /// <summary>
         /// 绘制二维码
         /// </summary>
         /// <param name="context"></param>
         private void GetQRCode(HttpContext context)
         {
             string encodeData = GameRequest.GetQueryString("qt");
             string icoURL = GameRequest.GetQueryString("qm");
             int width = GameRequest.GetQueryInt("qs", );
             if (encodeData != string.Empty)
             {
                 calQrcode(encodeData, icoURL, width, context);
             }
         }

         /// <summary>
         /// 按照指定的大小绘制二维码
         /// </summary>
         /// <param name="sData"></param>
         /// <param name="width"></param>
         /// <returns></returns>
         private void calQrcode(string sData, string icoURL, int size, HttpContext context)
         {
             //二维码版本,大小获取
             Color qrCodeBackgroundColor = Color.White;
             Color qrCodeForegroundColor = Color.Black;
             int length = System.Text.Encoding.UTF8.GetBytes(sData).Length;

             //生成二维码数据
             QRCodeEncoder qrCodeEncoder = new QRCodeEncoder();
             qrCodeEncoder.QRCodeEncodeMode = QRCodeEncoder.ENCODE_MODE.BYTE;
             qrCodeEncoder.QRCodeErrorCorrect = QRCodeEncoder.ERROR_CORRECTION.M;//使用M纠错级别
             qrCodeEncoder.QRCodeVersion = ;
             var encodedData = qrCodeEncoder.Encode(sData, System.Text.Encoding.UTF8);

             //绘制图片
             int x = , y = ;
             int w = , h = ;
             // 二维码矩阵单边数据点数目
             int count = encodedData.Length;
             // 获取单个数据点边长
             double sideLength = Convert.ToDouble(size) / count;
             // 初始化背景色画笔
             SolidBrush backcolor = new SolidBrush(qrCodeBackgroundColor);
             // 初始化前景色画笔
             SolidBrush forecolor = new SolidBrush(qrCodeForegroundColor);
             // 定义画布
             Bitmap image = new Bitmap(size, size);
             // 获取GDI+绘图图画
             Graphics graph = Graphics.FromImage(image);
             // 先填充背景色
             graph.FillRectangle(backcolor, , , size, size);

             // 变量数据矩阵生成二维码
             for (int row = ; row < count; row++)
             {
                 for (int col = ; col < count; col++)
                 {
                     // 计算数据点矩阵起始坐标和宽高
                     x = Convert.ToInt32(Math.Round(col * sideLength));
                     y = Convert.ToInt32(Math.Round(row * sideLength));
                     w = Convert.ToInt32(Math.Ceiling((col + ) * sideLength) - Math.Floor(col * sideLength));
                     h = Convert.ToInt32(Math.Ceiling((row + ) * sideLength) - Math.Floor(row * sideLength));

                     // 绘制数据矩阵
                     graph.FillRectangle(encodedData[col][row] ? forecolor : backcolor, x, y, w, h);
                 }
             }

             //添加LOGO
             string path = context.Server.MapPath("/favicon.ico");
             Bitmap logoImage = null;
             FileInfo fileInfo = new FileInfo(path);
             if (fileInfo.Exists)
             {
                 logoImage = new Bitmap(path);
             }
             if (icoURL != "")
             {
                 HttpWebRequest webRequest = (HttpWebRequest)HttpWebRequest.Create(icoURL);
                 try
                 {
                     HttpWebResponse webReponse = (HttpWebResponse)webRequest.GetResponse();
                     if (webReponse.StatusCode == HttpStatusCode.OK)
                     {
                         using (Stream stream = webReponse.GetResponseStream())
                         {
                             Image img = Image.FromStream(stream);
                             logoImage = new Bitmap(img);
                             img.Dispose();
                         }
                     }
                 }
                 catch { }
             }
             if (logoImage != null)
             {
                 image = CoverImage(image, logoImage, graph);
                 logoImage.Dispose();
             }
             //输出
             System.IO.MemoryStream ms = new System.IO.MemoryStream();
             image.Save(ms, System.Drawing.Imaging.ImageFormat.Png);
             context.Response.ClearContent();
             context.Response.ContentType = "image/png";
             context.Response.AddHeader("Content-Disposition", "attachment;  filename=" + HttpUtility.UrlEncode("QRCodeImg.png", System.Text.Encoding.UTF8));
             context.Response.BinaryWrite(ms.ToArray());
             context.Response.Flush();
             context.Response.End();
             image.Dispose();
         }

         /// <summary>
         /// 层叠图片
         /// </summary>
         /// <param name="original">原始图片(目前只支持正方形)</param>
         /// <param name="image">层叠图片(目前只支持正方形)</param>
         /// <returns>处理以后的图片</returns>
         private Bitmap CoverImage(Bitmap original, Bitmap image, Graphics graph = null)
         {
             //缩放附加图片
             int sideSLen = original.Width;
             int sideTLen = sideSLen / ;
             image = ResizeImage(image, sideTLen, sideTLen);

             // 获取GDI+绘图图画
             graph = graph == null ? Graphics.FromImage(original) : graph;

             // 将附加图片绘制到原始图中央
             graph.DrawImage(image, (original.Width - sideTLen) / , (original.Height - sideTLen) / , sideTLen, sideTLen);

             // 释放GDI+绘图图画内存
             graph.Dispose();

             // 返回处理结果
             return original;
         }

         /// <summary>
         /// 图片缩放
         /// </summary>
         /// <param name="bmp">原始Bitmap</param>
         /// <param name="newW">新的宽度</param>
         /// <param name="newH">新的高度</param>
         /// <returns>处理以后的图片</returns>
         private Bitmap ResizeImage(Bitmap original, int width, int height)
         {
             try
             {
                 Bitmap image = new Bitmap(width, height);
                 Graphics graph = Graphics.FromImage(image);
                 // 插值算法的质量
                 graph.CompositingQuality = CompositingQuality.HighQuality;
                 graph.SmoothingMode = SmoothingMode.HighQuality;
                 graph.InterpolationMode = InterpolationMode.HighQualityBicubic;
                 graph.DrawImage(original, new Rectangle(, , width, height),
                     new Rectangle(, , original.Width, original.Height), GraphicsUnit.Pixel);
                 graph.Dispose();
                 return image;
             }
             catch
             {
                 return null;
             }
         }       

         public bool IsReusable
         {
             get
             {
                 return false;
             }
         }
     }
 }