保存屏幕BMP

HBITMAP CopyScreenToBitmap(LPRECT lpRect)
{
 //屏幕和内存设备描述表
 HDC hSrcDC, hMemDC;
 //位图句柄
 HBITMAP hBitmap, hOldBitmap;
 //选定区域坐标
 int nX, nY, nX2, nY2;
 //位图宽度和高度
 int nWidth, nHeight;
 //屏幕分辨率
 int xScrn, yScrn;
 
 //确保选定区域不为空矩形
 if(IsRectEmpty(lpRect))
  return NULL;
 //为屏幕创建设备描述表
 hSrcDC = CreateDC("DISPLAY", NULL, NULL, NULL);
 //为屏幕设备描述表创建兼容的内存设备描述表
 hMemDC = CreateCompatibleDC(hSrcDC);
 //获得选定区域坐标
 nX = lpRect->left;
 nY = lpRect->top;
 nX2 = lpRect->right;
 nY2 = lpRect->bottom;
 //获得屏幕分辨率
 xScrn = GetDeviceCaps(hSrcDC, HORZRES);
 yScrn = GetDeviceCaps(hSrcDC, VERTRES);
 //确保选定区域是可见的
 if(nX<0)
  nX = 0;
 if(nY<0)
  nY = 0;
 if(nX2>xScrn)
  nX2 = xScrn;
 if(nY2>yScrn)
  nY2 = yScrn;
 nWidth = nX2 - nX;
 nHeight = nY2 - nY;
 //创建一个与屏幕设备描述表兼容的位图
 hBitmap = CreateCompatibleBitmap(hSrcDC, nWidth, nHeight);
 //把新位图选到内存设备描述表中
 hOldBitmap = (HBITMAP)SelectObject(hMemDC, hBitmap);
 //把屏幕设备描述表拷贝到内存设备描述表中
 BitBlt(hMemDC, 0, 0, nWidth, nHeight, hSrcDC, nX, nY, SRCCOPY);
 //得到屏幕位图的句柄
 hBitmap = (HBITMAP)SelectObject(hMemDC, hOldBitmap);
 //清除
 DeleteDC(hSrcDC);
 DeleteDC(hMemDC);
 //返回位置句柄
 return hBitmap;
}

HBITMAP CopyScreenToBitmap(int x1, int x2, int y1, int y2)
{
 //屏幕和内存设备描述表
 HDC hSrcDC, hMemDC;
 //位图句柄
 HBITMAP hBitmap, hOldBitmap;
 //选定区域坐标
 int nX, nY, nX2, nY2;
 //位图宽度和高度
 int nWidth, nHeight;
 //屏幕分辨率
 int xScrn, yScrn;
 /*
 //确保选定区域不为空矩形
 if(IsRectEmpty(lpRect))
 return NULL;*/
 //为屏幕创建设备描述表
 hSrcDC = CreateDC("DISPLAY", NULL, NULL, NULL);
 //为屏幕设备描述表创建兼容的内存设备描述表
 hMemDC = CreateCompatibleDC(hSrcDC);
 //获得选定区域坐标
 nX = x1;
 nY = y1;
 nX2 = x2;
 nY2 = y2;
 //获得屏幕分辨率
 xScrn = GetDeviceCaps(hSrcDC, HORZRES);
 yScrn = GetDeviceCaps(hSrcDC, VERTRES);
 //确保选定区域是可见的
 if(nX<0)
  nX = 0;
 if(nY<0)
  nY = 0;
 if(nX2>xScrn)
  nX2 = xScrn;
 if(nY2>yScrn)
  nY2 = yScrn;
 nWidth = nX2 - nX;
 nHeight = nY2 - nY;
 //创建一个与屏幕设备描述表兼容的位图
 hBitmap = CreateCompatibleBitmap(hSrcDC, nWidth, nHeight);
 //把新位图选到内存设备描述表中
 hOldBitmap = (HBITMAP)SelectObject(hMemDC, hBitmap);
 //把屏幕设备描述表拷贝到内存设备描述表中
 BitBlt(hMemDC, 0, 0, nWidth, nHeight, hSrcDC, nX, nY, SRCCOPY);
 //得到屏幕位图的句柄
 hBitmap = (HBITMAP)SelectObject(hMemDC, hOldBitmap);
 //清除
 DeleteDC(hSrcDC);
 DeleteDC(hMemDC);
 //返回位置句柄
 return hBitmap;
}

BOOL SaveCapturedBitmap(HBITMAP hBitmap, CString FileName)
{
 if(hBitmap==NULL || FileName.IsEmpty())
 {
  AfxMessageBox("参数错误");
  return false;
 }
 
 HDC hDC;
 //当前分辨率下每象素所占字节数
 int iBits;
 //位图中每象素所占字节数
 WORD wBitCount;
 //定义调色板大小， 位图中像素字节大小 ，位图文件大小 ， 写入文件字节数
 DWORD dwPaletteSize=0, dwBmBitsSize=0, dwDIBSize=0, dwWritten=0;
 //位图属性结构
 BITMAP Bitmap;
 //位图文件头结构
 BITMAPFILEHEADER bmfHdr;
 //位图信息头结构
 BITMAPINFOHEADER bi;
 //指向位图信息头结构
 LPBITMAPINFOHEADER lpbi;
 //定义文件，分配内存句柄，调色板句柄
 HANDLE fh, hDib, hPal,hOldPal=NULL;
 
 //计算位图文件每个像素所占字节数
 hDC = CreateDC("DISPLAY", NULL, NULL, NULL);
 iBits = GetDeviceCaps(hDC, BITSPIXEL) * GetDeviceCaps(hDC, PLANES);
 DeleteDC(hDC);
 if (iBits <= 1) wBitCount = 1;
 else if (iBits <= 4) wBitCount = 4;
 else if (iBits <= 8) wBitCount = 8;
 else      wBitCount = 24;
 
 GetObject(hBitmap, sizeof(Bitmap), (LPSTR)&Bitmap);
 bi.biSize   = sizeof(BITMAPINFOHEADER);
 bi.biWidth   = Bitmap.bmWidth;
 bi.biHeight   = Bitmap.bmHeight;
 bi.biPlanes   = 1;
 bi.biBitCount = wBitCount;
 bi.biCompression = BI_RGB;
 bi.biSizeImage = 0;
 bi.biXPelsPerMeter = 0;
 bi.biYPelsPerMeter = 0;
 bi.biClrImportant = 0;
 bi.biClrUsed = 0;
 
 dwBmBitsSize = ((Bitmap.bmWidth * wBitCount + 31) / 32) * 4 * Bitmap.bmHeight;
 
 //为位图内容分配内存
 hDib = GlobalAlloc(GHND,dwBmBitsSize + dwPaletteSize + sizeof(BITMAPINFOHEADER));
 lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDib);
 *lpbi = bi;
 
 // 处理调色板
 hPal = GetStockObject(DEFAULT_PALETTE);
 if (hPal)
 {
  hDC = ::GetDC(NULL);
  hOldPal = ::SelectPalette(hDC, (HPALETTE)hPal, FALSE);
  RealizePalette(hDC);
 }
 
 // 获取该调色板下新的像素值
 GetDIBits(hDC, hBitmap, 0, (UINT) Bitmap.bmHeight, (LPSTR)lpbi + sizeof(BITMAPINFOHEADER)
  +dwPaletteSize, (BITMAPINFO *)lpbi, DIB_RGB_COLORS);
 
 //恢复调色板
 if (hOldPal)
 {
  ::SelectPalette(hDC, (HPALETTE)hOldPal, TRUE);
  RealizePalette(hDC);
  ::ReleaseDC(NULL, hDC);
 }
 
 //创建位图文件
 fh = CreateFile(FileName, GENERIC_WRITE,0, NULL, CREATE_ALWAYS,
  FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN, NULL);
 
 if (fh == INVALID_HANDLE_VALUE) return FALSE;
 
 // 设置位图文件头
 bmfHdr.bfType = 0x4D42; // "BM"
 dwDIBSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + dwPaletteSize + dwBmBitsSize;
 bmfHdr.bfSize = dwDIBSize;
 bmfHdr.bfReserved1 = 0;
 bmfHdr.bfReserved2 = 0;
 bmfHdr.bfOffBits = (DWORD)sizeof(BITMAPFILEHEADER) + (DWORD)sizeof(BITMAPINFOHEADER) + dwPaletteSize;
 // 写入位图文件头
 WriteFile(fh, (LPSTR)&bmfHdr, sizeof(BITMAPFILEHEADER), &dwWritten, NULL);
 // 写入位图文件其余内容
 WriteFile(fh, (LPSTR)lpbi, dwDIBSize, &dwWritten, NULL);
 //清除
 GlobalUnlock(hDib);
 GlobalFree(hDib);
 CloseHandle(fh);
 
 return TRUE;
}