www.pudn.com > XAnalogClock_demo.zip > CDCBuffer.h

#ifndef CDCBUFFER_H 
#define CDCBUFFER_H 
 
class CDCBuffer 
{ 
public: 
	CDCBuffer() 
	{ 
		m_bValid = FALSE; 
		m_hOldBitmap = NULL; 
		m_hBitmap = NULL; 
		m_nBitmapID = 0; 
		m_sizeBitmap.cx = m_sizeBitmap.cy = 0; 
	} 
 
	~CDCBuffer() 
	{ 
		DeleteObject(); 
	} 
 
	void DeleteObject() 
	{ 
		if (m_hOldBitmap) 
			m_dcMemory.SelectObject(m_hOldBitmap); 
		m_hOldBitmap = NULL; 
 
		if (m_hBitmap) 
			::DeleteObject(m_hBitmap); 
		m_hBitmap = NULL; 
 
		m_bValid = FALSE; 
	} 
 
	BOOL LoadBitmap(UINT nBitmapID, CDC * pDC) 
	{ 
		TRACE(_T("in CDCBuffer::LoadBitmap for %d\n"), nBitmapID); 
 
		BOOL ok = FALSE; 
 
		DeleteObject(); 
 
		ASSERT(pDC); 
		ASSERT(nBitmapID); 
 
		HINSTANCE hInstResource = AfxFindResourceHandle(MAKEINTRESOURCE(nBitmapID), RT_BITMAP); 
 
		m_hBitmap = (HBITMAP)::LoadImage(hInstResource, MAKEINTRESOURCE(nBitmapID), 
							IMAGE_BITMAP, 0, 0, 0); 
		ASSERT(m_hBitmap); 
 
		if (m_hBitmap && pDC) 
		{ 
			m_dcMemory.DeleteDC(); 
 
			if (m_dcMemory.CreateCompatibleDC(pDC)) 
			{ 
				m_hOldBitmap = (HBITMAP)::SelectObject(m_dcMemory.m_hDC, m_hBitmap); 
				m_nBitmapID = nBitmapID; 
				m_bValid = TRUE; 
 
				m_sizeBitmap.cx = m_sizeBitmap.cy = 0; 
 
				BITMAP bm; 
				if (GetBitmap(&bm)) 
				{ 
					m_sizeBitmap.cx = bm.bmWidth; 
					m_sizeBitmap.cy = bm.bmHeight; 
					TRACE(_T("bitmap size = %d,%d\n"), m_sizeBitmap.cx, m_sizeBitmap.cy); 
				} 
				else 
				{ 
					TRACE(_T("ERROR - GetBitmap failed\n")); 
				} 
 
				ok = TRUE; 
			} 
			else 
			{ 
				TRACE(_T("ERROR - CreateCompatibleDC failed\n")); 
			} 
		} 
 
		return ok; 
	} 
 
	BOOL AttachBitmap(HBITMAP hBitmap, CDC * pDC) 
	{ 
		BOOL ok = FALSE; 
 
		DeleteObject(); 
 
		ASSERT(hBitmap); 
 
		m_hBitmap = hBitmap; 
 
		if (m_hBitmap && pDC) 
		{ 
			m_dcMemory.DeleteDC(); 
 
			if (m_dcMemory.CreateCompatibleDC(pDC)) 
			{ 
				m_hOldBitmap = (HBITMAP)::SelectObject(m_dcMemory.m_hDC, m_hBitmap); 
				m_nBitmapID = 0; 
				m_bValid = TRUE; 
				ok = TRUE; 
			} 
		} 
 
		return ok; 
	} 
 
	BOOL GetBitmap(BITMAP * pBM) 
	{ 
		BOOL ok = FALSE; 
		if (m_bValid && m_hBitmap) 
		{ 
			ok = ::GetObject(m_hBitmap, sizeof(BITMAP), pBM); 
		} 
		return ok; 
	} 
 
	BOOL IsValid() 
	{ 
		return m_bValid; 
	} 
 
	CDC			m_dcMemory; 
	HBITMAP		m_hBitmap; 
	CSize		m_sizeBitmap; 
 
protected: 
	BOOL		m_bValid; 
	HBITMAP		m_hOldBitmap; 
	UINT		m_nBitmapID; 
}; 
 
#endif //CDCBUFFER_H