📄 memdc.h
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#if !defined(_MEMDC_H_)#define _MEMDC_H_#if _MSC_VER >= 1000#pragma once#endif // _MSC_VER >= 1000// MemDC.h : header file////////////////////////////////////////////////////// RxMemDC - 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 Contextclass RxMemDC : public CDC{public: // constructor sets up the memory DC RxMemDC(CDC* pDC) : CDC() { ASSERT(pDC != NULL); m_pDC = pDC; m_pOldBitmap = NULL; m_bMemDC = !pDC->IsPrinting(); if (m_bMemDC) // Create a Memory DC { CWnd* pWnd = pDC->GetWindow(); if (pWnd) pWnd->GetClientRect(&m_rect); else pDC->GetClipBox(&m_rect); CreateCompatibleDC(pDC); m_bitmap.CreateCompatibleBitmap(pDC, m_rect.Width(), m_rect.Height()); m_pOldBitmap = SelectObject(&m_bitmap); SetWindowOrg(m_rect.left, m_rect.top); } else // Make a copy of the relevent parts of the current DC for printing { m_bPrinting = pDC->m_bPrinting; m_hDC = pDC->m_hDC; m_hAttribDC = pDC->m_hAttribDC; } } // Destructor copies the contents of the mem DC to the original DC ~RxMemDC() { 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); } 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 RxMemDC* operator->() {return this;} // Allow usage as a pointer operator RxMemDC*() {return this;}private: CBitmap m_bitmap; // Offscreen bitmap CBitmap* m_pOldBitmap; // bitmap originally found in RxMemDC 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(_MEMDC_H_)
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