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unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    procedure FormCreate(Sender: TObject);
    procedure FormDeactivate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
    procedure FormPaint(Sender: TObject);
    procedure FormResize(Sender: TObject);
    procedure FormClick(Sender: TObject);
  private
    { Private-Deklarationen }
  public
    { Public-Deklarationen }
  end;

var
  Form1: TForm1;
  bmp:TBitmap;
  cn:TCanvas;
  hnd:HWND;

implementation

uses Unit2;

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
  Application.OnDeactivate:=OnDeactivate;
  bmp:=TBitmap.create;
  cn:=TCanvas.create;
  hnd:=GetWindowDC(handle);
  cn.handle:=hnd;
end;

procedure TForm1.FormDeactivate(Sender: TObject);
begin
  cn.draw(0,0,bmp);
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  bmp.free;
  cn.Free;
  releasedc(handle,hnd);
end;

procedure TForm1.FormPaint(Sender: TObject);
begin
  cn.draw(0,0,bmp);
end;

procedure TForm1.FormResize(Sender: TObject);
begin
  bmp.width:=width;
  bmp.height:=GetSystemMetrics(SM_CYFRAME)*2+GetSystemMetrics(SM_CYCAPTION);
  bmp.Canvas.copyrect(bmp.canvas.cliprect,cn,bmp.canvas.cliprect);
end;

procedure TForm1.FormClick(Sender: TObject);
begin
  form2.show;
  cn.draw(0,0,bmp);
end;

end.