Как смешать две картинки?

procedure TacSpeedButton.Morphing(Bm1, Bm2: TBitmap; Progress: Integer);
var
  dstPixel, srcPixel: PRGBQuad;
  Weight: Integer;
  I: Integer;
begin
  if (Assigned(Bm1) and Assigned(B
m2)) then
  begin
    Bm1.PixelFormat := pf32bit;
    Bm2.PixelFormat := pf32bit;
    srcPixel := Bm2.ScanLine[Bm2.Height – 1];
    dstPixel := Bm1.ScanLine[Bm1.Height – 1];
    Weight := MulDiv(256, Progress, 100);
    for I := (Bm1.Width * Bm1.Height) – 1 downto 0 do
    begin
      with dstPixel^ do
      begin
        Inc(rgbRed, (Weight *
(srcPixel^.rgbRed – rgbRed)) shr 8);
        Inc(rgbGreen, (Weight * (srcPixel^.rgbGreen – rgbGreen)) shr 8);
        Inc(rgbBlue, (Weight * (srcPixel^.rgbBlue – rgbBlue)) shr 8);
      end;
      Inc(srcPixel);
      Inc(dstPixel);
    end;
  end;
end;