本例效果图:
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 Button1.Caption := '创建'; Button2.Caption := '退出'; end; procedure TForm1.Button1Click(Sender: TObject); var rgn: HRGN; begin rgn := CreateEllipticRgn(0, 0, Width, Height); SetWindowRgn(Handle, rgn, True); end; procedure TForm1.Button2Click(Sender: TObject); begin Close; end; end.