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  • 图片压缩存储(图片长宽过大时影响显示美观使用)

                    System.Drawing.Image tempimage = System.Drawing.Image.FromStream(imgFile.InputStream, true);
                    int imagewidth = tempimage.Width;//
                    int imageheight = tempimage.Height;//
    
                  DateTime now = DateTime.Now;
                    //计算文件的保存文件夹下
                    //用年/月/日做文件目录,这样避免一个文件夹下文件过多问题
                    //用文件的MD5值做文件名,这样避免多次上传同一副图片造成磁盘浪费
    
    
                    string fileName = "/Upload/" + now.Year + "/" + now.Month + "/" + now.Day + "/"
                        + CommonHelper.CalcMD5(imgFile.FileName) + fileExt;
                    imgFile.InputStream.Position = 0;
                    string imgFileFullPath = Server.MapPath("~" + fileName);
                    System.IO.Directory.CreateDirectory(Path.GetDirectoryName(imgFileFullPath));//如果文件夹不存在,则先创建文件夹
                    imageUrl = fileName;
    
    
    
                    if (imagewidth > 500 || imageheight > 600)
                    {                
                        byte[] bytes = WebHelper.CreateImg(tempimage, imageheight * 1.0 / imagewidth);
    using (Stream outStream = new FileStream(Server.MapPath(imageUrl), FileMode.Create))
                        {
                            outStream.Write(bytes, 0, bytes.Length);//类似于GetString                    
                        }
    
                    }
    
                    else
                    {
                        imgFile.SaveAs(imgFileFullPath);
                    }
            /// <summary>
            /// 生成一个验证码图片
            /// </summary>
            /// <param name="validCode">生成的验证码</param>
            /// <returns>图片的JPEG格式的二进制数据</returns>
            public static byte[] CreateImg(System.Drawing.Image imgOutput, double hw)
            {
                //常用汉字
                using (Bitmap bmp = new Bitmap(500, Convert.ToInt32(500 * hw)))
                using (Graphics g = Graphics.FromImage(bmp))
                using (MemoryStream ms = new MemoryStream())
                {
                    g.Clear(Color.White);
                    //修改成80×80大小 
                    System.Drawing.Image imgOutput2 = imgOutput.GetThumbnailImage(500, Convert.ToInt32(500 * hw), null, IntPtr.Zero);
    
                    g.DrawImage(imgOutput2, 0, 0);
                    Random rand = new Random();
    
                    bmp.Save(ms, ImageFormat.Jpeg);
                    ms.Position = 0;
                    return ms.ToArray();
                }
            }
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  • 原文地址:https://www.cnblogs.com/ink-heart/p/5899378.html
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