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;
}