Jak przesuwać elementy w schemacie programu? Reverse engineering

// DET - draw element type
#define DET_LOGIC_NOT							1
#define DET_LOGIC_AND							2
#define DET_LOGIC_OR							3

// 
typedef struct
{
	UINT uiType;
	CBitmap* pkObjectBmp;

} ELEMENT_INFO;

typedef struct
{
	ELEMENT_INFO* pkInfo;
	CRect rcElement;

} DRAW_ELEMENT_INFO;

typedef CTypedPtrList< CPtrList, ELEMENT_INFO* > ELEMENT_INFO_LIST;
typedef CTypedPtrList< CPtrList, DRAW_ELEMENT_INFO* > DRAW_ELEMENT_INFO_LIST;

// Load all bitmaps
loadElement( DET_LOGIC_NOT, IDB_LOGIC_NOT_BITMAP );
loadElement( DET_LOGIC_OR, IDB_LOGIC_OR_BITMAP );
loadElement( DET_LOGIC_AND, IDB_LOGIC_AND_BITMAP );

void CMainFrame::loadElement( const UINT cuiType, const UINT cuiResID )
{
	// Create
	ELEMENT_INFO* pkNewInfo = new ELEMENT_INFO;

	// Set
	pkNewInfo->uiType = cuiType;
	pkNewInfo->pkObjectBmp = new CBitmap();
	pkNewInfo->pkObjectBmp->LoadBitmap( cuiResID );

	BITMAP kBitmap;
	pkNewInfo->pkObjectBmp->GetBitmap( &kBitmap );
	pkNewInfo->pkObjectBmp->SetBitmapDimension( kBitmap.bmWidth, kBitmap.bmHeight );

	// Add
	m_kElementsList.AddHead( pkNewInfo );
}

void CElSimulatorView::OnDraw(CDC* pDC)
{
	CElSimulatorDoc* pDoc = GetDocument();
	ASSERT_VALID(pDoc);


	CDC MemDC;
	MemDC.CreateCompatibleDC( pDC );

	// get vec
	DRAW_ELEMENT_INFO_LIST* pkaDElements = pDoc->getDrawElementsListPtr();

	POSITION pos = pkaDElements->GetHeadPosition();
	DRAW_ELEMENT_INFO* pkDInfo;
	while ( pos && ( pkDInfo = pkaDElements->GetNext( pos ) ) != NULL )
	{
		// draw
		CBitmap* pkOldBitmap = ( CBitmap* )MemDC.SelectObject( ( CBitmap* )pkDInfo->pkInfo->pkObjectBmp );

		CSize size = pkDInfo->pkInfo->pkObjectBmp->GetBitmapDimension();
		pDC->BitBlt( pkDInfo->rcElement.left, pkDInfo->rcElement.top, size.cx, size.cy, &MemDC, 0, 0, SRCCOPY );

		if ( pkDInfo == m_pkSelectedItem )
			pDC->DrawFocusRect( pkDInfo->rcElement );
	}
}

void CElSimulatorView::OnLButtonDown(UINT nFlags, CPoint point)
{
	CElSimulatorDoc* pDoc = GetDocument();
	ASSERT_VALID(pDoc);

	//
	CPoint ptTmp = point;
	ptTmp.x += GetScrollPos( SB_HORZ );
	ptTmp.y += GetScrollPos( SB_VERT );

	// get vec
	DRAW_ELEMENT_INFO_LIST* pkaDElements = pDoc->getDrawElementsListPtr();

	// Check which element was clicked
	bool bFound = false;
	POSITION pos = pkaDElements->GetHeadPosition();
	DRAW_ELEMENT_INFO* pkDInfo;
	while ( pos && ( pkDInfo = pkaDElements->GetNext( pos ) ) != NULL )
	{
		// Got it
		if ( pkDInfo->rcElement.PtInRect( ptTmp ) )
		{
			bFound = true;
			m_pkSelectedItem = pkDInfo;
			m_pkDragingItem = pkDInfo;

			m_ptAdd.x = ptTmp.x - pkDInfo->rcElement.left;
			m_ptAdd.y = ptTmp.y - pkDInfo->rcElement.top;

			Invalidate();
			break;
		}
	}

	// No item clicked - clear selection
	if ( !bFound )
		m_pkSelectedItem = NULL;

	// Call base
	CScrollView::OnLButtonDown(nFlags, point);
}

void CElSimulatorView::OnLButtonUp(UINT nFlags, CPoint point)
{
	// Clear
	m_pkDragingItem = NULL;
	Invalidate();

	CScrollView::OnLButtonUp(nFlags, point);
}

void CElSimulatorView::OnMouseMove(UINT nFlags, CPoint point)
{
	// Drag item
	if ( m_pkDragingItem != NULL )
	{
		// get size
		CSize size = m_pkDragingItem->rcElement.Size();

		//
		CPoint ptTmp = point;
		ptTmp.x += GetScrollPos( SB_HORZ );
		ptTmp.y += GetScrollPos( SB_VERT );

		ptTmp -= m_ptAdd;

		// set new pos
		m_pkDragingItem->rcElement = CRect( ptTmp, size );

		Invalidate();
	}

	CScrollView::OnMouseMove(nFlags, point);
}