C#图像处理之霓虹效果实现方法

//定义霓虹处理函数
public Bitmap PNihong(Bitmap a)
{
 try
 {   
  int w = a.Width;
  int h = a.Height;
  Bitmap dstBitmap = new Bitmap(w, h, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
  System.Drawing.Imaging.BitmapData srcData = a.LockBits(new Rectangle
   (0, 0, w, h), System.Drawing.Imaging.ImageLockMode.ReadOnly, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
  System.Drawing.Imaging.BitmapData dstData = dstBitmap.LockBits(new Rectangle
   (0, 0, w, h), System.Drawing.Imaging.ImageLockMode.WriteOnly, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
  unsafe
  {
   byte* pIn = (byte*)srcData.Scan0.ToPointer();
   byte* pOut = (byte*)dstData.Scan0.ToPointer();
   byte* p;
   int stride = srcData.Stride;
   for (int y = 0; y < h; y++)
   {
   for (int x = 0; x < w; x++)
   {
    //边缘八个点像素不变
    if (x == 0 || x == w - 1 || y == 0 || y == h - 1)
    {
    pOut[0] = pIn[0];
    pOut[1] = pIn[1];
    pOut[2] = pIn[2];
    }
    else
    {
    int r0, r1, r2;
    int g1, g2, g0;
    int b1, b2, b0;
    double vR, vG, vB;
    //左上
    p = pIn - stride - 3;
    //右
    p = pIn + 3;
    r1 = p[2];
    g1 = p[1];
    b1 = p[0];
    //正下
    p = pIn + stride;
    r2 = p[2];
    g2 = p[1];
    b2 = p[0];
    //中心点
    p = pIn;
    r0 = p[2];
    g0 = p[1];
    b0 = p[0];
    //使用模板
    vR = Math.Sqrt((r0 - r1) * (r0 - r1) + (r0 - r2) * (r0 - r2));
    vG = Math.Sqrt((g0 - g1) * (g0 - g1) + (g0 - g2) * (g0 - g2));
    vB = Math.Sqrt((b0 - b1) * (b0 - b1) + (b0 - b2) * (b0 - b2));
    if (vR > 0)
    {
     vR = Math.Min(255, vR);
    }
    else
    {
     vR = Math.Max(0, vR);
    }
    if (vG > 0)
    {
     vG = Math.Min(255, vG);
    }
    else
    {
     vG = Math.Max(0, vG);
    }
    if (vB > 0)
    {
     vB = Math.Min(255, vB);
    }
    else
    {
     vB = Math.Max(0, vB);
    }
    pOut[0] = (byte)vB;
    pOut[1] = (byte)vG;
    pOut[2] = (byte)vR;
    }
    pIn += 3;
    pOut += 3;
   }
   pIn += srcData.Stride - w * 3;
   pOut += srcData.Stride - w * 3;
   }
  }
  a.UnlockBits(srcData);
  dstBitmap.UnlockBits(dstData);
  return dstBitmap;
 }
 catch (Exception e)
 {
  MessageBox.Show(e.Message.ToString());
  return null;
 }
}