CImage封装gdiplus的初始化和引用计数

（Owed by: 春夜喜雨 http://blog.csdn.net/chunyexiyu 转载请标明来源）
 
CImage内部封装了一个变量  
static
CInitGDIPlus s_initGDIPlus;
 
该变量实现了对gdiplus的初始化和销毁，基于引用计数的方式，实现了多个CImage实例的共享gdiplus的生命周期。
 

class CInitGDIPlus { public:       CInitGDIPlus() throw();       ~CInitGDIPlus() throw();         bool Init() throw();       void ReleaseGDIPlus() throw();       void IncreaseCImageCount() throw();       void DecreaseCImageCount() throw();   private:       ULONG_PTR m_dwToken;       CRITICAL_SECTION m_sect;       LONG m_nCImageObjects; }; inline CImage::CInitGDIPlus::CInitGDIPlus() throw() :       m_dwToken( 0 ), m_nCImageObjects( 0 ) {       __try       {            InitializeCriticalSection(&m_sect);       }       __except( STATUS_NO_MEMORY == GetExceptionCode() )       {            AtlThrow( E_OUTOFMEMORY );       } }   inline CImage::CInitGDIPlus::~CInitGDIPlus() throw() {       ReleaseGDIPlus();       DeleteCriticalSection(&m_sect); }   inline bool CImage::CInitGDIPlus::Init() throw() {       EnterCriticalSection(&m_sect);       bool fRet = true;       if( m_dwToken == 0 )       {            Gdiplus::GdiplusStartupInput input;            Gdiplus::GdiplusStartupOutput output;            Gdiplus::Status status = Gdiplus::GdiplusStartup( &m_dwToken, &input, &output );            if( status != Gdiplus::Ok )                  fRet = false;       }       LeaveCriticalSection(&m_sect);       return fRet; }   inline void CImage::CInitGDIPlus::ReleaseGDIPlus() throw() {       EnterCriticalSection(&m_sect);       if( m_dwToken != 0 )       {            Gdiplus::GdiplusShutdown( m_dwToken );       }       m_dwToken = 0;       LeaveCriticalSection(&m_sect); }   inline void CImage::CInitGDIPlus::IncreaseCImageCount() throw() {       EnterCriticalSection(&m_sect);       m_nCImageObjects++;       LeaveCriticalSection(&m_sect); }   inline void CImage::CInitGDIPlus::DecreaseCImageCount() throw() {       EnterCriticalSection(&m_sect);       if( --m_nCImageObjects == 0 )            ReleaseGDIPlus();       LeaveCriticalSection(&m_sect); }