unit VirSqr;

interface

uses VirPoint, Graphics, Graph;

type
//******************************************************************************
// odvozena trida od Point, definuje jeden ctverec
//******************************************************************************
  TVirSqr = class (TVirPoint)
  protected
    Site : Integer;
  public
    constructor Create(Xi, Yi, Sitei : Integer);
    procedure Grow(E: Integer); virtual;
    procedure Move; override;
    procedure Draw; override;
  end;

implementation

//******************************************************************************
//
//******************************************************************************
constructor TVirSqr.Create(Xi, Yi, Sitei: Integer);
begin
  inherited Create(Xi, Yi);
  Site := Sitei;
end;

//******************************************************************************
//
//******************************************************************************
procedure TVirSqr.Grow (E: Integer);
begin
 Site := Site + E;
 if Site > 50 then Site := 0;
end;

procedure TVirSqr.Move;
begin
  inherited Move;
  Grow(random(3));
end;

//******************************************************************************
//
//******************************************************************************
procedure TVirSqr.Draw;
begin
  Graph.Canvas.Pen.Color:=$00ff00;
  Graph.Canvas.Rectangle(X, Y, X+Site, Y+Site);
end;

end.