A Slider Control for C++

// SlideHolder.cpp : implementation file
//

#include "stdafx.h"
#include "SlideHolder.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CSlideHolder

CSlideHolder::CSlideHolder()
{
	m_nOffset = 0;
	m_nCurPage = 0;
	m_bTimerAlive = FALSE;
}

CSlideHolder::~CSlideHolder()
{
}


BEGIN_MESSAGE_MAP(CSlideHolder, CStatic)
	//{{AFX_MSG_MAP(CSlideHolder)
	ON_WM_TIMER()
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CSlideHolder message handlers

void CSlideHolder::OnTimer(UINT nIDEvent) 
{
	// TODO: Add your message handler code here and/or call default
	
	if( nIDEvent == 1 ) {
		CRect rect;
		GetWindowRect(rect);	

		m_nMoveAmount = (m_nOffsetEnd - m_nOffset) / 7;
		if( 0 < m_nMoveAmount && m_nMoveAmount < 5 ) {
			m_nMoveAmount = 5;
		}
		if( 0 > m_nMoveAmount && m_nMoveAmount > -5 ) {
			m_nMoveAmount = -5;
		}
		
		m_nOffset += m_nMoveAmount;
		
		//CString s;
		//s.Format("m_nOffset = %d, m_nOffsetEnd = %d, m_nMoveAmount = %d", m_nOffset, m_nOffsetEnd, m_nMoveAmount);
		//OutputDebugString(s);

		BOOL bFin = FALSE;
		if( m_nMoveAmount > 0 ) {
			if( m_nOffset >= m_nOffsetEnd ) {
				m_nOffset = m_nOffsetEnd;
				bFin = TRUE;
			}
		} else if( m_nMoveAmount == 0 ) {
			m_nOffset = m_nOffsetEnd;
			bFin = TRUE;
		} else {
			if( m_nOffset <= m_nOffsetEnd ) {
				m_nOffset = m_nOffsetEnd;
				bFin = TRUE;
			}			
		}

		int nFirst = GetFirstVisibleWnd(m_nOffset);
		if( nFirst != -1 && (nFirst+1) < m_aryWnd.GetSize() ) {
			//CString s;
			//s.Format("nFirst = %d", nFirst);
			//OutputDebugString(s);
			
			for( int i = 0; i < m_aryWnd.GetSize(); i++ ) {
				if( i != nFirst && i != (nFirst + 1) ) {
					CWnd* pWnd = (CWnd*)m_aryWnd.GetAt(i);
					if( pWnd ) {
						if( pWnd->IsWindowVisible() ) {
							pWnd->ShowWindow(SW_HIDE);
						}
					}
				}
			}

			
			CWnd* pWnd = (CWnd*)m_aryWnd.GetAt(nFirst);
			if( pWnd ) {
				pWnd->SetWindowPos(NULL, m_nOffset + (nFirst*rect.Width()), 0, 0, 0, SWP_NOSIZE|SWP_NOZORDER|SWP_SHOWWINDOW);
			}
			
			if( (nFirst + 1) < m_aryWnd.GetSize() ) {
				pWnd = (CWnd*)m_aryWnd.GetAt(nFirst+1);
				if( pWnd ) {
					pWnd->SetWindowPos(NULL, m_nOffset + ((nFirst+1)*rect.Width()), 0, 0, 0, SWP_NOSIZE|SWP_NOZORDER|SWP_SHOWWINDOW);
					//pWnd->Invalidate( FALSE );
				}
			}
		}
		
		
		if(bFin){
			m_bTimerAlive = FALSE;
			KillTimer(nIDEvent);
		}
	}
	
	CStatic::OnTimer(nIDEvent);
}

void CSlideHolder::AddPage(CWnd *pPage)
{
	CRect rect;
	GetWindowRect(rect);
	m_aryWnd.Add( pPage );
	pPage->SetWindowPos( NULL, 0, 0, rect.Width(), rect.Height(), SWP_NOMOVE|SWP_NOZORDER );
}

void CSlideHolder::MoveNext()
{
	CRect rect;
	GetWindowRect(rect);

	m_nCurPage++;
	if( m_nCurPage < 0 ) {
		m_nCurPage = 0;
	}
	if( m_nCurPage >= m_aryWnd.GetSize() ) {
		m_nCurPage = m_aryWnd.GetSize()-1;
	}

	m_nOffsetEnd = m_nCurPage * rect.Width() * (-1);
	//CString s;
	//s.Format("m_nOffsetEnd = %d", m_nOffsetEnd);
	//OutputDebugString(s);
	if( m_bTimerAlive == FALSE ) {
		m_bTimerAlive = TRUE;
		SetTimer( 1, 10, NULL );
	}
}

void CSlideHolder::MovePrev()
{
	CRect rect;
	GetWindowRect(rect);

	// 0 1 2
	// 3
	m_nCurPage--;
	if( m_nCurPage < 0 ) {
		m_nCurPage = 0;
	}
	if( m_nCurPage >= m_aryWnd.GetSize() ) {
		m_nCurPage = m_aryWnd.GetSize()-1;
	}

	m_nOffsetEnd = m_nCurPage * rect.Width() * (-1);
	if( m_bTimerAlive == FALSE ) {
		m_bTimerAlive = TRUE;
		SetTimer( 1, 10, NULL );
	}
}

int CSlideHolder::GetFirstVisibleWnd(int nOffset)
{
	CRect rect;
	GetWindowRect(rect);

	if( nOffset <= 0 ) { // +n
		// ___________________
		// |          |
		// 0          width
		for( int i = 0; ; i++ ) {
			int nLeft = rect.Width() * (i+1) * (-1);
			int nRight = nLeft + rect.Width();
			if( nLeft <= nOffset && nOffset <= nRight ) {
				return i;
			}
		}
	}

	return -1;
}

void CSlideHolder::SetCurrentPage(int nPage)
{
	CRect rect;
	GetWindowRect(rect);

	m_nCurPage = nPage;
	if( m_nCurPage < 0 ) {
		m_nCurPage = 0;
	}
	if( m_nCurPage >= m_aryWnd.GetSize() ) {
		m_nCurPage = m_aryWnd.GetSize()-1;
	}

	m_nOffsetEnd = m_nCurPage * rect.Width() * (-1);
	
	if( m_bTimerAlive == FALSE ) {
		m_bTimerAlive = TRUE;
		SetTimer( 1, 10, NULL );
	}
}