Capturando o conteúdo do desktop

Procedure TForm1.FormResize(Sender: TObject);
var
R : TRect;
DC : HDc;
Canv : TCanvas;
begin
R := Rect( 0, 0, Screen.Width, Screen.Height );
DC := GetWindowDC( GetDeskTopWindow );
Canv := TCanvas.Create;
Canv.Handle := DC;
Canvas.CopyRect( R, Canv, R );
ReleaseDC( GetDeskTopWindow, DC );
end;