procedure DrawTransparentBmp(Cnv: TCanvas; x,y: Integer; Bmp: TBitmap; clTransparent: TColor);
var
 bmpXOR, bmpAND, bmpINVAND, bmpTarget: TBitmap;
 oldcol: Longint;
begin
 try
 bmpAND := TBitmap.Create;
 bmpAND.Width := Bmp.Width;
 bmpAND.Height := Bmp.Height;
 bmpAND.Monochrome := True;
 oldcol := SetBkColor(Bmp.Canvas.Handle, ColorToRGB(clTransparent));
 BitBlt(bmpAND.Canvas.Handle, 0, 0, Bmp.Width, Bmp.Height, Bmp.Canvas.Handle, 0, 0, SRCCOPY);
 SetBkColor(Bmp.Canvas.Handle, oldcol);

 bmpINVAND := TBitmap.Create;
 bmpINVAND.Width := Bmp.Width;
 bmpINVAND.Height := Bmp.Height;
 bmpINVAND.Monochrome := True;
 BitBlt(bmpINVAND.Canvas.Handle, 0, 0, Bmp.Width, Bmp.Height, bmpAND.Canvas.Handle, 0, 0, NOTSRCCOPY);

 bmpXOR := TBitmap.Create;
 bmpXOR.Width := Bmp.Width;
 bmpXOR.Height := Bmp.Height;
 BitBlt(bmpXOR.Canvas.Handle, 0, 0, Bmp.Width, Bmp.Height, Bmp.Canvas.Handle, 0, 0, SRCCOPY);
 BitBlt(bmpXOR.Canvas.Handle, 0, 0, Bmp.Width, Bmp.Height, bmpINVAND.Canvas.Handle, 0, 0, SRCAND);

 bmpTarget := TBitmap.Create;
 bmpTarget.Width := Bmp.Width;
 bmpTarget.Height := Bmp.Height;
 BitBlt(bmpTarget.Canvas.Handle, 0, 0, Bmp.Width, Bmp.Height, Cnv.Handle, x, y, SRCCOPY);
 BitBlt(bmpTarget.Canvas.Handle, 0, 0, Bmp.Width, Bmp.Height, bmpAND.Canvas.Handle, 0, 0, SRCAND);
 BitBlt(bmpTarget.Canvas.Handle, 0, 0, Bmp.Width, Bmp.Height, bmpXOR.Canvas.Handle, 0, 0, SRCINVERT);
 BitBlt(Cnv.Handle, x, y, Bmp.Width, Bmp.Height, bmpTarget.Canvas.Handle, 0, 0, SRCCOPY);
 finally
 bmpXOR.Free;
 bmpAND.Free;
 bmpINVAND.Free;
 bmpTarget.Free;
 end;
end;