Image, перемещение и масштабирование изображения

Graphics::TBitmap*  GG = new Graphics::TBitmap;
GG->LoadFromFile("C:\\test.bmp");
Image1->Canvas->Draw(x,y,GG);

//---------------------------------------------------------------------------
 
#include <vcl.h>
#pragma hdrstop
 
#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
Graphics::TBitmap*  GG = new Graphics::TBitmap,*GGbuffer = new Graphics::TBitmap;
bool d=0;
int x2=0,y2=0;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
        : TForm(Owner)
{
}
//---------------------------------------------------------------------------
 
void __fastcall TForm1::FormCreate(TObject *Sender)
{
GG->LoadFromFile("F:\\test.bmp");
Image1->Canvas->Draw(0,0,GG);
    GGbuffer->Assign(GG);
DoubleBuffered=1;
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Image1MouseDown(TObject *Sender,
      TMouseButton Button, TShiftState Shift, int X, int Y)
{
if( Button==mbMiddle)
      d=1;
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Image1MouseUp(TObject *Sender, TMouseButton Button,
      TShiftState Shift, int X, int Y)
{
if( Button==mbMiddle)
  d=0;
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Image1MouseMove(TObject *Sender, TShiftState Shift,
      int X, int Y)
{
 
if(d)
{
 x2=X;
 y2=Y;
    Image1->Canvas->FillRect(Image1->Canvas->ClipRect);
    Image1->Canvas->Draw(x2,y2,GG);
}
 
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormMouseWheelDown(TObject *Sender,
      TShiftState Shift, TPoint &MousePos, bool &Handled)
{
    GG->Width=GG->Width+10;
     GG->Height=GG->Height+10;
 
     GG->Canvas->StretchDraw(GG->Canvas->ClipRect,GGbuffer);
 
 
     Image1->Canvas->FillRect(Image1->Canvas->ClipRect);
    Image1->Canvas->Draw(x2,y2,GG);
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormMouseWheelUp(TObject *Sender,
      TShiftState Shift, TPoint &MousePos, bool &Handled)
{
    GG->Width=GG->Width-10;
     GG->Height=GG->Height-10;
 
     GG->Canvas->StretchDraw(GG->Canvas->ClipRect,GGbuffer);
 
 
     Image1->Canvas->FillRect(Image1->Canvas->ClipRect);
    Image1->Canvas->Draw(x2,y2,GG);
}
//---------------------------------------------------------------------------