memdc.h

此次上传的使linux下的文件传输协议

#if !defined(AFX_CMemDC_H__9C109D44_F2A0_11D3_AC55_5254AB15D037__INCLUDED_)
#define AFX_CMemDC_H__9C109D44_F2A0_11D3_AC55_5254AB15D037__INCLUDED_

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000

class CMemDC : public CDC
{
private:
	CBitmap m_bitmap;     // Offscreen bitmap     //离屏位图
	CBitmap* m_oldBitmap; // bitmap originally found in CMemDC  CMemDC中最初找到的位图
	CDC* m_pDC; // Saves CDC passed in constructor  
	CRect m_rect; // Rectangle of drawing area.    //绘图的矩形区域
	BOOL m_bMemDC; // TRUE if CDC really is a Memory DC. //如果是真，说明CDC已经在内存DC里面了
public:
	CMemDC(CDC* pDC, CRect rect = CRect(0,0,0,0)):CDC(), m_oldBitmap(NULL), m_pDC(pDC)
	{
		ASSERT(m_pDC != NULL); // If you asserted here, you passed in a NULL CDC.
		m_bMemDC = !pDC->IsPrinting();
		if (m_bMemDC)
		{
			CreateCompatibleDC(pDC);
			if (rect==CRect(0,0,0,0)) //如果矩形为空，矩形就等于剪贴板的矩形
			{
				pDC->GetClipBox(&m_rect);
			}
			else
			{
				m_rect = rect;
			}
			m_bitmap.CreateCompatibleBitmap(pDC, m_rect.Width(), m_rect.Height());
            //根据pDC创建兼容位图
			m_oldBitmap = SelectObject(&m_bitmap); //把旧的位图选下
			SetWindowOrg(m_rect.left, m_rect.top); //设置窗口原点到矩形的左上角
		}
		else
		{
			// Make a copy of the relevent parts of the current DC for printing
			m_bPrinting = pDC->m_bPrinting;  //目前正处于打印设备环境中
			m_hDC = pDC->m_hDC;
			m_hAttribDC = pDC->m_hAttribDC;
		}
	}
	~CMemDC()
	{
		if (m_bMemDC) 
		{
			m_pDC->BitBlt(m_rect.left, m_rect.top, m_rect.Width(), m_rect.Height(),	this, m_rect.left, m_rect.top, SRCCOPY);
			SelectObject(m_oldBitmap);
		}
		else 
		{
			m_hDC = m_hAttribDC = NULL;
		}
	}
	CMemDC* operator->() 
	{
		return this;
	}
	operator CMemDC*() 
	{
		return this;
	}
};

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

//{{AFX_INSERT_LOCATION}}
// Microsoft Visual C++ will insert additional declarations immediately before the previous line.

#endif // !defined(AFX_CMemDC_H__9C109D44_F2A0_11D3_AC55_5254AB15D037__INCLUDED_)