Как в Delphi 7 сделать круг разделенный на сектора различного цвета

unit MainU;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls;
 
type
  TForm1 = class(TForm)
    Image1: TImage;
    Button1: TButton;
    Button3: TButton;
    Button4: TButton;
    ColorDialog1: TColorDialog;
    Timer1: TTimer;
    procedure FormCreate(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Timer1Timer(Sender: TObject);
    procedure Button4Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  Form1: TForm1;
  zsector:byte;
const
zc:array[1..6]of tcolor=(clblack,clyellow,clred,clgreen,clblue,clmaroon);
implementation
 
{$R *.dfm}
 
procedure zpie(n:byte;c:tcolor);
begin
with form1.Image1.Canvas do
begin
brush.Color:=c;
pie(0,0,337,337,round((sin((n*pi)/3)+1)*168),round((cos((n*pi)/3)+1)*168),round((sin(((n+1)*pi)/3)+1)*168),round((cos(((n+1)*pi)/3)+1)*168));
end;
end;
 
procedure TForm1.FormCreate(Sender: TObject);
var
i:integer;
begin
zsector:=6;
for i:=1 to 6 do
zpie(i,zc[i]);
end;
 
procedure TForm1.Button1Click(Sender: TObject);
begin
if colordialog1.Execute then
zpie(1,colordialog1.Color);
end;
 
procedure TForm1.Button3Click(Sender: TObject);
begin
if button3.Caption='Стоп' then
begin
timer1.Enabled:=false;
button3.Caption:='Пуск';
end
else
begin
timer1.Enabled:=true;
button3.Caption:='Стоп';
end;
end;
 
procedure TForm1.Timer1Timer(Sender: TObject);
begin
zpie(zsector,zc[zsector]);
if zsector=6 then
zsector:=1
else
zsector:=zsector+1;
zpie(zsector,colordialog1.Color);
end;
 
procedure TForm1.Button4Click(Sender: TObject);
begin
close;
end;
 
end.