type

 TForm1 = class(TForm)

  procedure FormMouseDown(Sender: TObject; Button: TMouseButton;

  Shift: TShiftState; X, Y: Integer);

  procedure FormMouseMove(Sender: TObject;

  Shift: TShiftState; X, Y: Integer);

  procedure FormMouseUp(Sender: TObject; Button: TMouseButton;

  Shift: TShiftState; X, Y: Integer);

 private

  {Private declarations}

  Capturing : bool;

  Captured : bool;

  StartPlace : TPoint;

  EndPlace : TPoint;

 public

  {Public declarations}

end;

var

 Form1: TForm1;

implementation

{$R *.DFM}

function MakeRect(Pt1: TPoint; Pt2: TPoint): TRect;

begin

 if pt1.x < pt2.x then

 begin

  Result.Left := pt1.x;

  Result.Right := pt2.x;

 end

 else

 begin

  Result.Left := pt2.x;

  Result.Right := pt1.x;

 end;

 if pt1.y < pt2.y then

 begin

  Result. := pt1.y;

  Result.Bottom := pt2.y;

 end

 else

 begin

  Result. := pt2.y;

  Result.Bottom := pt1.y;

 end;

end;

procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;

Shift: TShiftState; X, Y: Integer);

begin

 if Captured then

  DrawFocusRect(Form1.Canvas.Handle,MakeRect(StartPlace, EndPlace));

 StartPlace.x := X;

 StartPlace.y := Y;

 EndPlace.x := X;

 EndPlace.y := Y;

 DrawFocusRect(Form1.Canvas.Handle, MakeRect(StartPlace, EndPlace));

 Capturing := true;

 Captured := true;

end;

procedure TForm1.FormMouseMove(Sender: TObject;

Shift: TShiftState; X, Y: Integer);

begin

 if Capturing then

 begin

  DrawFocusRect(Form1.Canvas.Handle,MakeRect(StartPlace,EndPlace));

  EndPlace.x := X;

  EndPlace.y := Y;

  DrawFocusRect(Form1.Canvas.Handle,MakeRect(StartPlace,EndPlace));

 end;

end;

procedure TForm1.FormMouseUp(Sender: TObject; Button: TMouseButton;

Shift: TShiftState; X, Y: Integer);

begin

 Capturing := false;

end;