asp.net实现生成缩略图及加水印的方法示例

本文实例讲述了asp.net实现生成缩略图及给原始图加水印的方法。分享给大家供大家参考，具体如下：

using System.IO;
    using System.Drawing.Imaging;
PRivate void Button1_ServerClick(object sender, System.Eventargs e) {
      Graphics g=null;
      System.Drawing.Image upimage=null;
      System.Drawing.Image thumimg=null;
      System.Drawing.Image simage=null;
      BITmap outputfile=null;
  try   {
        string extension = Path.GetExtension(File1.PosteDFile.FileName).ToUpPEr();
        string filename = DateTime.Now.ToString("yyyyMMddhhmmss");
        string smallpath = Server.MapPath(".")+"/smallimg/";
        string Bigpath = Server.MapPath(".")+"/bigimg/";
        int width,height,newwidth,newheight;
        System.Drawing.Image.GetThumbnailImageAbort callb =new System.Drawing.Image.GetThumbnailImageAbort(ThumbnailCallback);
        if(!Directory.Exists(smallpath))    Directory.CreateDirectory(smallpath);
        if(!Directory.Exists(bigpath))    Directory.CreateDirectory(bigpath);
        Stream upimgfile = File1.PostedFile.InputStream;
        string simagefile = Server.MapPath("a8LOGo.jpg");
     //要加水印的文件    simage=System.Drawing.Image.FromFile(simagefile);
        upimage= System.Drawing.Image.FromStream(upimgfile);
     //上传的图片    width = upimage.Width;
        height = upimage.Height;
        if(width>
height)     {
          newwidth=200;
          newheight =(int)((double)height/(double)width * (double)newwidth);
    }
 else     {
          newheight=200;
          newwidth=(int)((double)width/(double)height * (double)newheight);
    }
        thumimg = upimage.GetThumbnailImage(newwidth,newheight,callb,IntPtr.Zero);
        outputfile=new Bitmap(upimage);
        g=Graphics.FromImage(outputfile);
        g.DrawImage(simage,new Rectangle(upimage.Width-simage.Width,upimage.Height-simage.Height,upimage.Width,upimage.Height),0,0,upimage.Width,upimage.Height,GraphicsUnit.Pixel);
        string newpath = bigpath + filename + extension;
     //原始图路径    string thumpath = smallpath + filename + extension;
     //缩略图路径    outputfile.Save(newpath);
        thumimg.Save(thumpath);
        outputfile.Dispose();
  }
  catch(Exception ex)   {
        throw ex;
  }
  finally   {
        if(g!=null)    g.Dispose();
        if(thumimg!=null)    thumimg.Dispose();
        if(upimage!=null)    upimage.Dispose();
        if(simage!=null)    simage.Dispose();
  }
}
public bool ThumbnailCallback() {
      return false;
}
    

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