lyfz_repos/经典版源码/MonitoringCenter/DB/GridCtrl/MemDC.h

#if !defined(AFX_MEMDC_H__CA1D3541_7235_11D1_ABBA_00A0243D1382__INCLUDED_)
#define AFX_MEMDC_H__CA1D3541_7235_11D1_ABBA_00A0243D1382__INCLUDED_

#if _MSC_VER >= 1000
#pragma once
#endif // _MSC_VER >= 1000
// MemDC.h : header file
//

//////////////////////////////////////////////////
// CMemDC - memory DC
//
// Author: Keith Rule
// Email:  keithr@europa.com
// Copyright 1996-1997, Keith Rule
//
// You may freely use or modify this code provided this
// Copyright is included in all derived versions.
//
// History - 10/3/97 Fixed scrolling bug.
//                   Added print support.
//           25 feb 98 - fixed minor assertion bug
//
// This class implements a memory Device Context

class CMemDC : public CDC
{
public:

	// constructor sets up the memory DC
	CMemDC(CDC* pDC) : CDC()
	{
		ASSERT(pDC != NULL);

		m_pDC = pDC;
		m_pOldBitmap = NULL;
#ifndef WCE_NO_PRINTING
		m_bMemDC = !pDC->IsPrinting();
#else
		m_bMemDC = FALSE;
#endif

		if (m_bMemDC)    // Create a Memory DC
		{
			pDC->GetClipBox(&m_rect);
			CreateCompatibleDC(pDC);
			m_bitmap.CreateCompatibleBitmap(pDC, m_rect.Width(), m_rect.Height());
			m_pOldBitmap = SelectObject(&m_bitmap);

			////2011-11-02 add
			//DeleteObject( m_bitmap );
			//DeleteObject( pDC );
#ifndef _WIN32_WCE
			SetWindowOrg(m_rect.left, m_rect.top);
#endif
			// EFW - Bug fix - Fill background in case the user has overridden
			// WM_ERASEBKGND.  We end up with garbage otherwise.
			// CJM - moved to fix a bug in the fix.
			FillSolidRect(m_rect, pDC->GetBkColor());
		}
		else        // Make a copy of the relevent parts of the current DC for printing
		{
#if !defined(_WIN32_WCE) || ((_WIN32_WCE > 201) && !defined(WCE_NO_PRINTING))
			m_bPrinting = pDC->m_bPrinting;
#endif
			m_hDC = pDC->m_hDC;
			m_hAttribDC = pDC->m_hAttribDC;
		}

	}

	// Destructor copies the contents of the mem DC to the original DC
	~CMemDC()
	{
		if (m_bMemDC)
		{
			// Copy the offscreen bitmap onto the screen.
			m_pDC->BitBlt(m_rect.left, m_rect.top, m_rect.Width(), m_rect.Height(),
				this, m_rect.left, m_rect.top, SRCCOPY);

			//Swap back the original bitmap.
			SelectObject(m_pOldBitmap);
			//2011-11-02 add
			//DeleteObject( m_pDC );
		}
		else {
			// All we need to do is replace the DC with an illegal value,
			// this keeps us from accidently deleting the handles associated with
			// the CDC that was passed to the constructor.
			m_hDC = m_hAttribDC = NULL;
		}
	}

	// Allow usage as a pointer
	CMemDC* operator->() { return this; }

	// Allow usage as a pointer
	operator CMemDC*() { return this; }

private:
	CBitmap  m_bitmap;      // Offscreen bitmap
	CBitmap* m_pOldBitmap;  // bitmap originally found in CMemDC
	CDC*     m_pDC;         // Saves CDC passed in constructor
	CRect    m_rect;        // Rectangle of drawing area.
	BOOL     m_bMemDC;      // TRUE if CDC really is a Memory DC.
};

/////////////////////////////////////////////////////////////////////////////

//{{AFX_INSERT_LOCATION}}
// Microsoft Developer Studio will insert additional declarations immediately before the previous line.

#endif // !defined(AFX_MEMDC_H__CA1D3541_7235_11D1_ABBA_00A0243D1382__INCLUDED_)