CMemoryDC封装类

#ifndef __MEMDC_H__  #define __MEMDC_H__  //Author:www.baojy.com  class CMemoryDC :public CDC  {  CSize m_size;  public:  //析构函数，释放加载的位图资源~CMemoryDC()  {  DeleteDC();  }CMemoryDC()  {  m_size.cx = m_size.cy = 0;  } //在构造对象的同时，根据资源ID加载位图CMemoryDC(UINT nBitmapID,CDC* pDC=NULL)  {  LoadBitmap(nBitmapID,pDC);  } //在构造对象的同时，从进程外，根据位图文件绝对路径名加载位图CMemoryDC(LPCTSTR szBitmapFile,CDC* pDC=NULL)  {  LoadBitmap(szBitmapFile,pDC);  }//在构造对象的同时，创建一块空白画布CMemoryDC(int cx,int cy,CDC* pDC = NULL)  {  Create(cx,cy,pDC);  }  //根据资源ID加载位图 BOOL LoadBitmap(UINT nBitmapID,CDC* pDC=NULL)  {  CBitmap bitmap;  bitmap.LoadBitmap(nBitmapID);  BITMAP bm;  bitmap.GetBitmap(&bm);  m_size.cx = bm.bmWidth;  m_size.cy = bm.bmHeight;  CreateCompatibleDC(pDC);  SelectObject(bitmap);  return TRUE;  }  //从进程外，根据位图文件绝对路径名加载位图BOOL LoadBitmap(LPCTSTR szBitmapFile,CDC* pDC=NULL)  {  HBITMAP hBitmap = (HBITMAP)LoadImage(AfxGetInstanceHandle(),  szBitmapFile,IMAGE_BITMAP,0,0,LR_LOADFROMFILE);  BITMAP bm;  GetObject(hBitmap,sizeof(bm),&bm);  m_size.cx = bm.bmWidth;  m_size.cy = bm.bmHeight;  CreateCompatibleDC(pDC);  SelectObject(hBitmap);        return TRUE;  } //绘制透明位图void BitTrans(  int nXDest,     // 目标起点X  int nYDest,     // 目标起点Y  int nWidthDest, // 目标宽度  int nHeightDest,// 目标高度  CDC* pDC,       // 目标DC  int nXSrc,      // 来源起点X  int nYSrc,      // 来源起点Y  COLORREF crTrans// 透明色  )  {  CMemoryDC dcImage(nWidthDest, nHeightDest,pDC);//临时DC  CBitmap bmpMask;  bmpMask.CreateBitmap(nWidthDest, nHeightDest, 1, 1, NULL);            // 创建单色掩码位图  CDC dcMask;//掩码DC   dcMask.CreateCompatibleDC(pDC);  dcMask.SelectObject(bmpMask);  //将载入位图的内存DC中的位图，拷贝到临时DC中  dcImage.BitBlt( 0, 0, nWidthDest, nHeightDest, this, nXSrc, nYSrc, SRCCOPY);  // 设置临时DC的透明色  dcImage.SetBkColor(crTrans);  //掩码DC的透明区域为白色其它区域为黑色  dcMask.BitBlt(0, 0, nWidthDest, nHeightDest, &dcImage, 0, 0, SRCCOPY);  //临时DC透明区域为黑色，其它区域保持不变  dcImage.SetBkColor(RGB(0,0,0));  dcImage.SetTextColor(RGB(255,255,255));  dcImage.BitBlt( 0, 0, nWidthDest, nHeightDest, &dcMask, 0, 0, SRCAND);  // 目标DC透明部分保持屏幕不变，其它部分变成黑色  pDC ->SetBkColor(RGB(255,255,255));  pDC ->SetTextColor(RGB(0,0,0));  pDC ->BitBlt(nXDest, nYDest, nWidthDest, nHeightDest, &dcMask, 0, 0, SRCAND);  pDC ->BitBlt(nXDest, nYDest, nWidthDest, nHeightDest, &dcImage, 0, 0, SRCPAINT);  }   //绘制具有可拉伸的透明位图void StretchTrans(  int nXDest,         // 目标起点X  int nYDest,         // 目标起点Y  int nWidthDest,     // 目标宽度  int nHeightDest,    // 目标高度  CDC* pDC,           // 目标DC  int nXSrc,          // 来源起点X  int nYSrc,          // 来源起点Y  int nWidthSrc,      // 来源宽度  int nHeightSrc,     // 来源高度  COLORREF crTrans    // 透明色  )  {  CMemoryDC dcImage(nWidthDest, nHeightDest,pDC);//临时DC  CBitmap bmpMask;  // 创建单色掩码位图  bmpMask.CreateBitmap(nWidthDest, nHeightDest, 1, 1, NULL);  CDC dcMask;  dcMask.CreateCompatibleDC(pDC);  dcMask.SelectObject(bmpMask);  // 将载入位图的内存DC中的位图，拷贝到临时DC中  if (nWidthDest == nWidthSrc && nHeightDest == nHeightSrc)  dcImage.BitBlt(0, 0, nWidthDest, nHeightDest, this, nXSrc, nYSrc, SRCCOPY);  else  dcImage.StretchBlt(0, 0, nWidthDest, nHeightDest,   this, nXSrc, nYSrc, nWidthSrc, nHeightSrc, SRCCOPY);  // 设置临时DC的透明色  dcImage.SetBkColor( crTrans);  //掩码DC的透明区域为白色其它区域为黑色  dcMask.BitBlt(0,0,nWidthDest, nHeightDest,&dcImage,0,0,SRCCOPY);  //临时DC透明区域为黑色，其它区域保持不变  dcImage.SetBkColor(RGB(0,0,0));  dcImage.SetTextColor(RGB(255,255,255));  dcImage.BitBlt(0, 0, nWidthDest, nHeightDest, &dcMask, 0, 0, SRCAND);  // 目标DC透明部分保持屏幕不变，其它部分变成黑色  pDC ->SetBkColor(RGB(255,255,255));  pDC ->SetTextColor(RGB(0,0,0));  pDC ->BitBlt(nXDest, nYDest, nWidthDest, nHeightDest, &dcMask, 0, 0, SRCAND);  pDC ->BitBlt(nXDest, nYDest, nWidthDest, nHeightDest, &dcImage, 0, 0, SRCPAINT);  }        //创建一张空白内存画布  BOOL Create(int cx,int cy,CDC* pDC = NULL)  {  this->CreateCompatibleDC(pDC);  CBitmap bitmap;  if(pDC)  bitmap.CreateCompatibleBitmap(pDC,cx,cy);  else  bitmap.CreateCompatibleBitmap(&CClientDC(NULL),cx,cy);  m_size.cx = cx;  m_size.cy = cy;  this->SelectObject(bitmap);  return TRUE;  }  //摧毁  BOOL DeleteDC()  {  if(!GetSafeHdc())  return TRUE;  CBitmap * pBitmap = GetCurrentBitmap();  pBitmap ->DeleteObject();  return CDC::DeleteDC();  }  //根据当前DC中的位图和透明色，去掉透明色，生成一个除透明色外不规则的区域void GenerateRgn(CRgn &DesRgn,COLORREF clTrans){DesRgn.CreateRectRgn(0,0,0,0);int i(0),j(0);while (i < m_size.cx){j = 0;while (j < m_size.cy){if (GetPixel(i,j) - clTrans){CRgn rgTemp;rgTemp.CreateRectRgn(i,j,i+1,j+1);DesRgn.CombineRgn(&DesRgn,&rgTemp,RGN_OR);}j++;}i++;}}  inline int Width(){return m_size.cx;}  inline int Height(){return m_size.cy;}  };  #endif //__MEMDC_H__