C#生成高清缩略图-白红宇

C#生成高清缩略图

阅读量：6308 次

发布时间：2019-06-22

本文共 1764 字，大约阅读时间需要 5 分钟。

                  01          /// <summary>          
       
                  02             /// 为图片生成缩略图            
       
                  03             /// </summary>          
       
                  04             /// <param name="phyPath">原图片的路径</param>          
       
                  05             /// <param name="width">缩略图宽</param>          
       
                  06             /// <param name="height">缩略图高</param>          
       
                  07             /// <returns></returns>          
       
                  08             public System.Drawing.Image GetThumbnail(System.Drawing.Image image, int width, intheight)          
       
                  09             {          
       
                  10                 Bitmap bmp = newBitmap(width, height);          
       
                  11                 //从Bitmap创建一个System.Drawing.Graphics          
       
                  12                 System.Drawing.Graphics gr = System.Drawing.Graphics.FromImage(bmp);          
       
                  13                 //设置           
       
                  14                 gr.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;          
       
                  15                 //下面这个也设成高质量          
       
                  16                 gr.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;          
       
                  17                 //下面这个设成High          
       
                  18                 gr.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;          
       
                  19                 //把原始图像绘制成上面所设置宽高的缩小图          
       
                  20                 System.Drawing.Rectangle rectDestination = newSystem.Drawing.Rectangle(0, 0, width, height);          
       
                  21                       
       
                  22                 gr.DrawImage(image, rectDestination, 0, 0, image.Width, image.Height, GraphicsUnit.Pixel);          
       
                  23                 returnbmp;          
       
                  24             }

调用方法

                  01          HttpPostedFile file = photoFile.PostedFile;          
       
                  02                  if(!file.ContentType.Contains("image"))          
       
                  03                  {          
       
                  04          return"照片格式不合法";          
       
                  05                  }          
       
                  06                  stringext = Path.GetExtension(file.FileName).ToLower();          
       
                  07                  if (ext != ".jpg" && ext != ".gif" && ext != ".png"&& ext != ".jpeg")          
       
                  08                  {          
       
                  09          return"请您上传jpg、gif、png图片";          
       
                  10                  }          
       
                  11                  if(file.ContentLength > 5 * 1024 * 1024)          
       
                  12                  {          
       
                  13          return"请您上传512字节内的图片";          
       
                  14                  }          
       
                  15                  stringnewName = Guid.NewGuid().ToString();          
       
                  16                  stringtempPath = "upload/";          
       
                  17                  stringimg = tempPath + newName + ext;          
       
                  18                  stringfilePath = Server.MapPath(img);          
       
                  19                  if(!Directory.Exists(tempPath))          
       
                  20                  {          
       
                  21                      Directory.CreateDirectory(tempPath);          
       
                  22                  }          
       
                  23                  using(System.Drawing.Image originalImage = System.Drawing.Image.FromStream(file.InputStream))          
       
                  24                  {          
       
                  25                      GetThumbnail(originalImage, 504, 374).Save(filePath);          
       
                  26                  }