How to create a Canvas object in Lazarus and add it to a PaintBox?

In a Form I have a Paintbox with property Align = alClient and a Button .

I need to draw a Canvas object within Paintbox in the Button OnCLick event . This is the Canvas object to create:

const IconSize:Integer = 10
type
  Icon = Class   
  public
    posX, posY:Integer;
    constructor Create(X,Y:Integer);
    destructor Destroy;
    procedure SetX(AValue: Integer);
    procedure SetY(AValue: Integer);
  published
    property LocationX : Integer read posX write SetX;
    property LocationY : Integer read posY write SetY;
end;     
var CanvasIcon: Icon;

This is the constructor method of the object:

constructor Icon.Create(X, Y: Integer);
var Bitmap:TBitmap;
begin
  Bitmap:=TBitmap.Create;
  try
    Bitmap.Height := IconSize;
    Bitmap.Width := IconSize;
    Bitmap.Canvas.Pen.Color := clBlack;
    Bitmap.Canvas.Rectangle(Round(X-(IconSize/2)), Round(Y-(IconSize/2)),
      Round(X+(IconSize/2)), Round(Y+(IconSize/2)));
    PaintBox.Canvas.Draw(0, 0, Bitmap);
  finally
    Bitmap.Free;
  end;
end;   

And this is the OnClick event of the Button :

procedure TFormPaintBox.Button1Click(Sender: TObject);
begin
  CanvasIcon:=Icon.Create(10,10);
end;

However, Lazarus displays the following error message:

  

src / unitpaintbox.pas (121,33) Error: Wrong number of parameters specified for call to "Create"

But the constructor receives two parameters, exactly as it was specified in the Button event of Button . How can I solve this problem?