unit Unit1;interfaceuses  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,  Dialogs;type  TForm1 = class(TForm)    procedure FormPaint(Sender: TObject);  end;var  Form1: TForm1;implementation{$R *.dfm}procedure TForm1.FormPaint(Sender: TObject);const  n = 50;var  Rgn: HRGN;  x1,y1,x2,y2: Integer;begin  x1 := n;  y1 := n div 2;  x2 := ClientWidth - n;  y2 := ClientHeight - n;  {建立矩形区域}  Rgn := CreateRectRgn(x1, y1, x2, y2);  //Rgn := CreateRectRgnIndirect(Rect(x1, y1, x2, y2)); {目的同上一行, 只是参数要一个矩形结构}  {填充区域}  Canvas.Brush.Color := clSilver;  Canvas.Brush.Style := bsCross;  FillRgn(Canvas.Handle, Rgn, Canvas.Brush.Handle);  {绘制区域边界}  Canvas.Brush.Color := clRed;  Canvas.Brush.Style := bsSolid;  FrameRgn(Canvas.Handle, Rgn, Canvas.Brush.Handle, 2, 2);  DeleteObject(Rgn);end;end.