Efeito desligamento (cinza)

procedure TForm7.Button1Click(Sender: TObject);

begin

  ShowMessage('Tanso');

end;

procedure TForm7.FormShow(Sender: TObject);

var

  ADC: HDC;

  x,y,b : Integer;

  Cor : Integer;

begin

  ADC         := GetDC( 0  );

  BitBlt( Image.Canvas.Handle,0,0,Self.Width,Self.Height, ADC,

          Form7.Left, Form7.Top, srcCopy  );

  b := 0;

  y := 0;

  while y <= Self.Height - 1 do

          begin

             x := 0;

             while x <= Self.Width - 1 do

                 begin

                 Inc( b );

                 if Cor = clBlack then

                      cor := ClGray

                 else

                      cor := clBlack;

                 if Odd( b ) then

                     SetPixel( Image.Canvas.Handle, X, Y, cor );

                 Inc( x );

                 end;

             Inc( b );

             Inc( y );

          end;

  ReleaseDC( 0, ADC );

end;