Captcha en Delphi

unit fmain;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Image1: TImage;
    procedure letrasAnguladas(c : string; angulo : integer; nextPos : Integer);
    function PalabraAleatoria(Longitud: integer): string;
    procedure generaImg();
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.letrasAnguladas(c : string; angulo : integer; nextPos : Integer);
var
   logfont:TLogFont;
   font: Thandle;
begin
   LogFont.lfheight:=30;
   logfont.lfwidth:=10;
   logfont.lfweight:=900;

   LogFont.lfEscapement:=angulo;
   logfont.lfcharset:=1;
   logfont.lfoutprecision:=OUT_TT_ONLY_PRECIS;
   logfont.lfquality:= DEFAULT_QUALITY;
   logfont.lfpitchandfamily:= FF_SWISS;
   logfont.lfUnderline := 0;
   logfont.lfStrikeOut := 0;

   font:=createfontindirect(logfont);

   Selectobject(Image1.canvas.handle,font);

   SetTextColor(Image1.canvas.handle,rgb(0,180,0));
   SetBKmode(Image1.canvas.handle,transparent);

   Image1.canvas.textout(nextPos,5,c);
   SetTextColor(Image1.canvas.handle,rgb(Random(255),Random(255),Random(255)));
   deleteobject(font);
end;

function TForm1.PalabraAleatoria(Longitud: integer): string;
const
  Letras = '01234567890ABCDEFGHIJKLMNPRSTUVWXYZ';
var
  n  : integer;
begin
  Result:='';
  for n:=1 to Longitud do Result:=Result+Letras[1+Random(Length(Letras))];
end;

procedure TForm1.generaImg();
var
   palabra : string;
   vX : integer;
begin
   Randomize;
   palabra := PalabraAleatoria(Random(6)+4);
   if length(palabra) > 6 then
      palabra := copy(palabra,1,6);
   for vX := 1 to Length(palabra) do
      letrasAnguladas(palabra[vX],Random(600)+1,25*vX-15);
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
   Image1.Picture.LoadFromFile('blanco.bmp'); 
   generaImg;
end;

end.