unit1.pas

一系列DELPHI的控件如何使用的例子,例子有的比较简单,但是能详细的说明了控件的使用,对许多刚涉足DELPHI的朋友会很有帮助的

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Image1: TImage;
    ProgressBar1: TProgressBar;
    TrackBar1: TTrackBar;
    Timer1: TTimer;
    BitBtn1: TBitBtn;
    BitBtn2: TBitBtn;
    procedure TrackBar1Change(Sender: TObject);
    procedure Timer1Timer(Sender: TObject);
  private
    r:integer;
    procedure DrawImage(radius:integer);
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation
{$R *.dfm}
procedure Tform1.DrawImage(radius:integer);
var x1,x2,y1,y2:integer;
begin
  x1:=90-radius;
  y1:=x1;
  x2:=90+radius;
  y2:=x2;
  with Image1.canvas do
    brush.Style:=bsSolid;
    brush.Color:=clwindow;
    fillrect(image1.Canvas.ClipRect);
    brush.Color:=clred;
    Ellipse(x1,y1,x2,y2);
  begin

  end;
end;

procedure TForm1.TrackBar1Change(Sender: TObject);
begin
   DrawImage(TrackBar1.Position);
end;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
   drawimage(r);
   r:=r+2;
   if r>90 then
     timer1.Enabled:=false;
end;

end.