本例效果图:
![](https://www.cnblogs.com/images/cnblogs_com/del/129733/o_84303.gif)
![](https://www.cnblogs.com/images/cnblogs_com/del/129733/o_84303.gif)
unit Unit1; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls; type TForm1 = class(TForm) Button1: TButton; procedure FormCreate(Sender: TObject); procedure Button1Click(Sender: TObject); procedure FormDblClick(Sender: TObject); end; var Form1: TForm1; implementation {$R *.dfm} procedure TForm1.FormCreate(Sender: TObject); begin Button1.Caption := '创建'; end; 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) ); var rgn: HRGN; begin rgn := CreatePolygonRgn(pts, Length(pts), 1); {1:ALTERNATE; 2:WINDING} SetWindowRgn(Handle, rgn, True); end; procedure TForm1.FormDblClick(Sender: TObject); begin Close; end; end.