Как нарисовать линию!

Form1->Canvas->MoveTo(x,y);
Form1->Canvas->LineTo(x,y);

bool drawing;
TPoint orig_pt, move_pt;
 
void DrawLine(TCanvas *Canv, const TPoint &pt1, const TPoint &pt2, TPenMode pm)
{
    Canv->Pen->Mode = pm;
    Canv->MoveTo(pt1.x, pt1.y);
    Canv->LineTo(pt2.x, pt2.y);
}
//---------------------------------------------------------------------------
 
void __fastcall TForm1::FormMouseDown(TObject *Sender, TMouseButton Button,
      TShiftState Shift, int X, int Y)
{
    drawing = true;
    orig_pt = Point(X, Y);
    move_pt = orig_pt;
}
//---------------------------------------------------------------------------
 
void __fastcall TForm1::FormMouseMove(TObject *Sender, TShiftState Shift,
      int X, int Y)
{
    if (drawing)
    {
        DrawLine(Canvas, orig_pt, move_pt, pmNotXor);
        move_pt = Point(X, Y);
        DrawLine(Canvas, orig_pt, move_pt, pmNotXor);
    }
}
//---------------------------------------------------------------------------
 
void __fastcall TForm1::FormMouseUp(TObject *Sender, TMouseButton Button,
      TShiftState Shift, int X, int Y)
{
    if (drawing)
    {
        DrawLine(Canvas, orig_pt, Point(X, Y), pmCopy);
        drawing = false;
    }
}
//---------------------------------------------------------------------------