Simplificacion de la libreria DelphiZXingQRCodeEx

[darkamerico]

Saludos amigos,
Deseo utilizar la librería DelphiZXingQRCodeEx, sin tener un formulario lleno de parámetros, sino definiéndolas directamente en código, realice un pequeño proyecto para este fin, la unidad principal se puede ver a continuación:

Código Delphi [-]
unit uPrincipal;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.ExtCtrls, DelphiZXingQRCode,
  Vcl.StdCtrls;

type
  TForm1 = class(TForm)
    pbPreview: TPaintBox;
    btnGenerarQR: TButton;
    lblQRMetrics: TLabel;
    procedure btnGenerarQRClick(Sender: TObject);
    procedure pbPreviewPaint(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    FQRCode: TDelphiZXingQRCode;
    FAltFixed: Boolean;
  public
    procedure RemakeQR;
  end;

var
  Form1: TForm1;

implementation

uses QRGraphics, QR_Win1251, QR_URL, jpeg;

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
  FQRCode := TDelphiZXingQRCode.Create;
  FQRCode.RegisterEncoder(ENCODING_WIN1251, TWin1251Encoder);
  FQRCode.RegisterEncoder(ENCODING_URL, TURLEncoder);
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  FQRCode.Free
end;

procedure TForm1.pbPreviewPaint(Sender: TObject);
begin
  with pbPreview.Canvas do
  begin
    Pen.Color := clBlack;
    Brush.Color := clBlack;
  end;
  DrawQR(pbPreview.Canvas, pbPreview.ClientRect, FQRCode, 0, TQRDrawingMode(0 div 2), Boolean(1 - 0 mod 2));
end;

procedure TForm1.RemakeQR;
begin
  with FQRCode do
  try
    BeginUpdate;
    Data := 'atg';
    Encoding := 0; // Auto
    ErrorCorrectionOrdinal := TErrorCorrectionOrdinal(1);
    QuietZone := 4;
    EndUpdate(True);
    lblQRMetrics.Caption := IntToStr(Columns) + 'x' + IntToStr(Rows) + ' (' +
      IntToStr(Columns - QuietZone * 2) + 'x' + IntToStr(Rows - QuietZone * 2) +
      ')';
  finally
    pbPreview.Repaint;
  end;
end;

procedure TForm1.btnGenerarQRClick(Sender: TObject);
var
  H: Integer;
begin
  FAltFixed := False;
  FQRCode := nil;

  pbPreview.Repaint;

end;

end.

Podrian ayudarme en hacerlo funcionar cuando presione el botón Generar.

Atte
Americo Torres