unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    procedure FormCreate(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
  Canvas.Pen.Width := 2;
  Canvas.Pen.Color := clRed;
  Canvas.Brush.Color := clYellow;
end;

{绘制多边形; 它的参数是一个点数组, 这里定义了一个常数数组}
procedure TForm1.Button1Click(Sender: TObject);
const
  pts: array[0..3] of TPoint = (
    (x:10; y:40),
    (x:46; y:120),
    (x:82; y:40),
    (x:46; y:10)
  );
begin
  Canvas.Polygon(pts);
end;

{绘制连续的一组直线; 它的参数也是一个点数组, 我只是把上面的平移了一点}
procedure TForm1.Button2Click(Sender: TObject);
const
  pts: array[0..3] of TPoint = (
    (x:10+82; y:40),
    (x:46+82; y:120),
    (x:82+82; y:40),
    (x:46+82; y:10)
  );
begin
  Canvas.Polyline(pts);
end;

end.


//效果图: