按比例生成缩略图 

 1 public static void saveTwoImages(string imgName,string simgName,string strPath,System.Web.UI.HtmlControls.HtmlInputFile imageUp)
 2   {
 3    //生成原图
 4    Byte[] oFileByte = new byte[imageUp.PostedFile.ContentLength];
 5    System.IO.Stream oStream = imageUp.PostedFile.InputStream;
 6    System.Drawing.Image oImage = System.Drawing.Image.FromStream(oStream);
 7    int oWidth = oImage.Width; //原图宽度
 8    int oHeight = oImage.Height; //原图高度
 9    int tWidth = 100; //设置缩略图初始宽度
10    int tHeight = 100; //设置缩略图初始高度
11    string imgExt = getFileExtName(imageUp);
12    //按比例计算出缩略图的宽度和高度
13    if(oWidth >= oHeight)
14    {
15     tHeight = (int)Math.Floor(Convert.ToDouble(oHeight) * (Convert.ToDouble(tWidth) / Convert.ToDouble(oWidth)));
16    }
17    else
18    {
19     tWidth = (int)Math.Floor(Convert.ToDouble(oWidth) * (Convert.ToDouble(tHeight) / Convert.ToDouble(oHeight)));
20    }
21    //生成缩略原图
22    Bitmap tImage = new Bitmap(tWidth,tHeight);
23    Graphics g = Graphics.FromImage(tImage);
24    g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High; //设置高质量插值法
25    g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;//设置高质量,低速度呈现平滑程度
26    g.Clear(Color.Transparent); //清空画布并以透明背景色填充
27    g.DrawImage(oImage,new Rectangle(0,0,tWidth,tHeight),new Rectangle(0,0,oWidth,oHeight),GraphicsUnit.Pixel);
28    string oFullName = strPath + imgName; //保存原图的物理路径
29    string tFullName = strPath + simgName; //保存缩略图的物理路径
30    try
31    {
32     //以JPG格式保存图片
33     switch(imgExt.ToLower())
34     {
35      case "jpg":
36       oImage.Save(oFullName,System.Drawing.Imaging.ImageFormat.Jpeg);
37       tImage.Save(tFullName,System.Drawing.Imaging.ImageFormat.Jpeg);//
38       break;
39      case "gif":
40       oImage.Save(oFullName, System.Drawing.Imaging.ImageFormat.Gif);
41       tImage.Save(tFullName,System.Drawing.Imaging.ImageFormat.Gif);
42       break;
43      case "png":
44       oImage.Save(oFullName, System.Drawing.Imaging.ImageFormat.Bmp);
45       tImage.Save(tFullName,System.Drawing.Imaging.ImageFormat.Bmp);
46       break;
47     }
48    }
49    catch(Exception ex)
50    {
51     throw ex;
52    }
53    finally
54    {
55     //释放资源
56     oImage.Dispose();
57     g.Dispose();
58     tImage.Dispose();
59    }
60   }

使用方法：

string strTime=General.getDateTime();
     string strExt=General.getFileExtName(File1);
     strPicture=strUserId+"ShopZ"+strTime+"."+strExt;
     strSPicture=strUserId+"ShopS"+strTime+"."+strExt;
     string strFilePath=Server.MapPath("Images/");
     try
     {
      saveTwoImages(strPicture,strSPicture,strFilePath,File1);
     }

 

posted @ 2014-04-24 10:56  追逐者——Eagle  阅读(286)  评论(0)  编辑  收藏  举报