Закруглить углы многоугольника

unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls,Math,Grids;
 
type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Edit1: TEdit;
    Edit2: TEdit;
    Label1: TLabel;
    Label2: TLabel;
    Button3: TButton;
    Button4: TButton;
    Edit3: TEdit;
    Label3: TLabel;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  Form1: TForm1;
 
implementation
 
{$R *.dfm}
var n,x0,y0,i:integer;
    p:array of Tpoint;
    an,ak,r,d:real;
procedure TForm1.Button1Click(Sender: TObject);
begin
randomize;
n:=StrToInt(Edit1.Text);
r:=StrToInt(Edit2.Text);
ak:=360/n;
x0:=Form1.Width div 2;
y0:=Form1.Height div 2;
Setlength(p,n+1);
an:=0;
for i:=0 to n-1 do
  begin
    p[i].x:=x0+round(r*cos(an*pi/180));
    p[i].y:=y0-round(r*sin(an*pi/180));
    an:=an+ak;
  end;
p[n].x:=p[0].x;
p[n].y:=p[0].y;
Canvas.MoveTo(p[0].x,p[0].y);
Canvas.Pen.Color:=random($fffff);
Canvas.Pen.Width:=2;
for i:=0 to n do
Canvas.LineTo(p[i].x,p[i].y);
end;
 
procedure TForm1.Button2Click(Sender: TObject);
begin
Form1.Invalidate;
end;
 
procedure TForm1.Button3Click(Sender: TObject);
var j:integer;
begin
randomize;
n:=StrToInt(Edit1.Text);
x0:=Form1.Width div 2;
y0:=Form1.Height div 2;
ak:=360/n;
an:=0;
Canvas.Pen.Style:=psDot;
Canvas.Pen.Color:=random($fffff);
Canvas.Pen.Width:=1;
for j:=0 to n-1 do
 begin
 p[j].x:=x0+round(r*cos(an*pi/180));
 p[j].y:=y0-round(r*sin(an*pi/180));
 an:=an+ak;
Canvas.MoveTo(x0,y0);
Canvas.LineTo(p[j].x,p[j].y);
 end;
end;
end.

    
    d[i].x:= Ox + round(radius*cos(a*pi/180));
    d[i].y:= Oy - round(radius*sin(a*pi/180));