Fade em Imagem

var
   nAux: TPoint;
begin
   // -> Issu aki vai dentro de algum FOR
      nAux.x := Random(image1.width);
      nAux.y := Random(image1.Height);
      image1.canvas.pixels[nAux.x,nAux.y] := image2.canvas.pixels[nAux.x,nAux.y]
end;

procedure TForm1.Button1Click(Sender: TObject);

 procedure FadeOut(const BMP:TImage; Pause:integer);
  var
   BytesPorScan  : integer;
   w,h           : integer;
   p             : pByteArray;
   counter       : integer;

  begin
     {This only works with 24 or 32 bits bitmaps}
     If Not (BMP.Picture.Bitmap.PixelFormat
             in [pf24Bit, pf32Bit])
      then raise exception.create
         (´Error, bitmap format not supported.´);

     try
      BytesPorScan:=
       Abs(Integer(BMP.Picture.Bitmap.ScanLine[1])-
           Integer(BMP.Picture.Bitmap.ScanLine[0]));
     except
       raise exception.create(´Error´);
     end;

     {Decrease the RGB for each single pixel}
     for counter:=1 to 256 do
     begin
       for h:=0 to BMP.Picture.Bitmap.Height-1 do
       begin
         P:=BMP.Picture.Bitmap.ScanLine[h];
         for w:=0 to BytesPorScan-1 do
           if P^[w] >0 then P^[w]:=P^[w]-1;
       end;
       Sleep(Pause);
     BMP.Refresh;
     end;
   end; {procedure FadeOut}
 begin 
   FadeOut(Image1,5);
 end;

var
  res : TBitmap;
  bf : _BLENDFUNCTION;
begin
  res := TBitmap.create;
  try
    res.width := i1.picture.width;
    res.height := i1.picture.height;
    res.assign(i1.picture.bitmap);


    bf.BlendOp := AC_SRC_OVER;
    bf.BlendFlags := 0;
    bf.SourceConstantAlpha := XXX;
    bf.AlphaFormat := 0;
    AlphaBlend(res.canvas.handle, 0,0,res.width,res.height,i2.picture.bitmap.Canvas.handle,0,0,res.width,res.height,bf);
    i3.Picture.assign(res);
  finally
    res.free;
  end;

{$EXTERNALSYM AlphaBlend}
function AlphaBlend(DC: HDC; p2, p3, p4, p5: Integer; DC6: HDC; p7, p8, p9, p10: Integer; p11: TBlendFunction): BOOL; stdcall;