C#图像处理之图像平移的方法

//定义图像平移函数
private static Bitmap offsetp(Bitmap a,int s,int v)
{
 System.Drawing.Imaging.BitmapData srcData = a.LockBits(new Rectangle (0,0,a.Width ,a.Height) ,System .Drawing .Imaging .ImageLockMode .ReadWrite ,a.PixelFormat );
 IntPtr ptr = srcData.Scan0;
 int bytes = srcData.Stride * a.Height;
 byte[]grayVlaues=new byte[bytes];
 System.Runtime.InteropServices.Marshal.Copy(ptr ,grayVlaues ,0,bytes);
 byte[] tempArray=new byte[bytes];
 for (int i = 0; i < bytes; i++)
 {
  tempArray[i] = 255;
 }
 for (int i = 0; i < a.Width * 3; i += 3)
 {
  if ((i + s*3) < a.Width*3 && (i + s*3) > 0)
  {
   for (int j = 0; j < a.Height; j++)
   {
   if ((j + v) < a.Height && (j + v) > 0)
   {
   tempArray[(i + s * 3) + (j + v) * srcData.Stride] = grayVlaues[i + j * srcData.Stride];
   tempArray[i + s * 3 + 1 + (j + v) * srcData.Stride] = grayVlaues[i + 1 + j * srcData.Stride];
   tempArray[i + s * 3 + 2 + (j + v) * srcData.Stride] = grayVlaues[i + 2 + j * srcData.Stride];
   }
   }
  }
  }
 grayVlaues = (byte[])tempArray.Clone();
 System.Runtime.InteropServices.Marshal.Copy(grayVlaues ,0,ptr, bytes);
 a.UnlockBits(srcData );
 return a;
}