void __fastcall TForm1::Button1Click(TObject *Sender)
{
  Graphics::TBitmap *Bmp = new Graphics::TBitmap();      
  Graphics::TBitmap* Elli=new Graphics::TBitmap;      Bmp->LoadFromFile("1.bmp");
  Bmp->PixelFormat=pf24bit;
  byte *ptr1,*ptr2;
  RECT  R;
  HRGN MyRgn = CreateEllipticRgn(0, 0, Bmp->Width, Bmp->Height); 
  HRGN hRgn1 = CreateEllipticRgn(0, 0, 100, 100);
  HRGN hRgn2 = CreateEllipticRgn(0, 0, 0, 0);      CombineRgn(MyRgn, hRgn1, hRgn2, RGN_XOR);
  Elli->PixelFormat = pf24bit;
  Elli->Width       = Bmp->Width;
  Elli->Height      = Bmp->Height;      for(int y=0; yHeight; y  )
  {
    ptr1=(byte*)(Elli->ScanLine[y]);
    ptr2=(byte*)(Bmp->ScanLine[y]);
    for(int x=0; xWidth; x  )
    {
      if (PtInRegion(MyRgn, x, y))
      {
        Byte Gray=(ptr2[3*x] ptr2[3*x 1] ptr2[3*x 2])/3;
        ptr1[3*x] = Gray;
        ptr1[3*x 1] = Gray;
        ptr1[3*x 2] = Gray;
      }
    }
  }
  Image1->Transparent=true;
  Image1->Picture->Assign(Elli);
  DeleteObject(hRgn1);
  DeleteObject(hRgn2);
  DeleteObject(MyRgn);
  delete Bmp;
  delete Elli;
}