Отталкивание шара от стенок

void __fastcall TForm2::FormCreate(TObject *Sender)
{
bitmap = new Graphics::TBitmap;

//---------------------------------------------------------------------------
 
#include <vcl.h>
#pragma hdrstop
 
#include "Unit5.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma link "acPNG"
#pragma resource "*.dfm"
TForm5 *Form5;
int iSpeed=10;
//---------------------------------------------------------------------------
__fastcall TForm5::TForm5(TComponent* Owner)
    : TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TForm5::Timer1Timer(TObject *Sender)
{
TRect null;
if(IntersectRect(null, Image1->BoundsRect, Panel1->BoundsRect)){iSpeed=0;}
}
//---------------------------------------------------------------------------
 
 
void __fastcall TForm5::FormKeyDown(TObject *Sender, WORD &Key, TShiftState Shift)
 
{
TRect null;
if(Key=='W')
{
    Image1->Top-=iSpeed;
    if(iSpeed==0)
    {
        iSpeed=10;
    }
}
if(Key=='S')
{
    Image1->Top+=iSpeed;
    if(iSpeed==0)
    {
        iSpeed=10;
    }
}
if(Key=='A')
{
    Image1->Left-=iSpeed;
        if(iSpeed==0)
    {
        iSpeed=10;
    }
}
if(Key=='D')
{
    Image1->Left+=iSpeed;
}
}
//---------------------------------------------------------------------------