IMAGE S, D;
      BYTE    *R, *G, *B, *E;
      char    *ptr;
      int  x, y, Width, Height;
      double Gx,Gy,pi=3.14159;
      Width = Image1->Picture->Bitmap->Width;
      Height = Image1->Picture->Bitmap->Height;
      S.LoadImg(Image1->Picture->Bitmap);
      R = new BYTE[Width*Height];
      G = new BYTE[Width*Height];
      B = new BYTE[Width*Height];
      E = new BYTE[Width*Height];           for(y=0;yPicture->Bitmap->ScanLine[y];
        for(x=0;x -(pi/8)) && (fabs(Gy) fabs(Gx))/2>100 )
                  {
                    E[y*Width x] = 255;
                    a= E[y*Width x];                        }
               else if ( atan(Gy/Gx)<(3*pi/8) && atan(Gy/Gx)>(pi/8) && (fabs(Gy) fabs(Gx))/2>100 )
                   {
                    E[y*Width x] = 255;
                    b= E[y*Width x];                        }
                else if ( atan(Gy/Gx)<(5*pi/8) && atan(Gy/Gx)>(3*pi/8) && (fabs(Gy) fabs(Gx))/2>100 )
                    {
                      E[y*Width x] = 255;
                      c= E[y*Width x];                          }
                else if ( atan(Gy/Gx)< -(pi/8) && atan(Gy/Gx)> -(3*pi/8) && (fabs(Gy) fabs(Gx))/2>100 )
                    {
                      E[y*Width x] = 255;
                      d= E[y*Width x];                          }
                  
            }
        }
    if(a==255 && (fabs(Gy) fabs(Gx))/2>100)
       ShowMessage("這是0度");
    else if(b==255 && (fabs(Gy) fabs(Gx))/2>100)
       ShowMessage("這是45度");
    else if(c==255 && (fabs(Gy) fabs(Gx))/2>100)
       ShowMessage("這是90度");
    else if(d==255 && (fabs(Gy) fabs(Gx))/2>100)
       ShowMessage("這是135度");
    ShowMessage(fabs(Gx));
    Image2->Picture->Bitmap->Width = Image1->Picture->Bitmap->Width;
    Image2->Picture->Bitmap->Height = Image1->Picture->Bitmap->Height;
    Image2->Picture->Bitmap->PixelFormat = pf24bit;        for(y=0;yPicture->Bitmap->ScanLine[y];
        for(x=0;xPicture->Bitmap);
    Image2->Refresh();        delete R;
    delete G;
    delete B;