sjfrm.pas

本光盘是《Delphi 7应用教程》一书的配套光盘

unit SJFRM;

interface

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

type
  TForm1 = class(TForm)
    Timer1: TTimer;
    procedure FormShow(Sender: TObject);
    procedure Timer1Timer(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  Num:integer;
  x,y:integer;

implementation

{$R *.dfm}

procedure TForm1.FormShow(Sender: TObject);
begin
   Form1.Canvas.Ellipse(5,5,155,155);

end;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
 Form1.Canvas.Pen.Width :=3;
 if num=0 then
    begin
       x:=0;
       y:=-65;
       Form1.Canvas.Pen.Mode:=pmCopy;
       Form1.Canvas.Ellipse(5,5,155,155);
       Form1.Canvas.MoveTo(80,80);
       Form1.Canvas.pen.Color :=Clred;
       Form1.Canvas.LineTo(80+x,80+y);
    end
 else
    begin
     //  Form1.Canvas.pen.Color :=Clred;
       Form1.Canvas.Pen.Mode :=pmNotXor;
       num:=num mod 360;
       Form1.Canvas.MoveTo(80,80);
       Form1.Canvas.LineTo(80+x,80+y);
       x:=Floor(65*sin(Num*3.1415926/180));
       y:=Floor((-1)*65*cos(Num*3.1415926/180));
       Form1.Canvas.Pen.Mode:=pmCopy;
       Form1.Canvas.MoveTo(80,80);
       Form1.Canvas.LineTo(80+x,80+y);
   end;
   num:=num+12;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  Num:=0;
end;

end.