c#生成缩略图

2022-07-15 80酷酷网 80kuku.com

　　缩略图private void ShowThumbnail(string oldfile, string newfile, int h, int w)
  {

   System.Drawing.Image img = System.Drawing.Image.FromFile(oldfile);
   System.Drawing.Image.GetThumbnailImageAbort myCallback = new System.Drawing.Image.GetThumbnailImageAbort(ThumbnailCallback);

int oldh = img.Height;
int oldw = img.Width;

int newh,neww;

double h1 = oldh*1.0/h;
double w1 = oldw*1.0/w;

double f = (h1>w1)? h1:w1;

   if(f < 1.0)
   {
    newh = oldh;
    neww = oldw;
   }
   else
   {
    newh = (int)(oldh/f);
    neww = (int)(oldw/f);
   }

System.Drawing.Image myThumbnail = img.GetThumbnailImage(neww, newh, myCallback, IntPtr.Zero);

myThumbnail.Save(newfile, System.Drawing.Imaging.ImageFormat.Jpeg);

   img.Dispose();
   myThumbnail.Dispose();
  }
  private bool ThumbnailCallback()
  {
   return false;
  }