VC下把HBITMAP保存为bmp图片

//VC下把HBITMAP保存为bmp图片 
BOOL  SaveBmp(HBITMAP     hBitmap,   CString     FileName)       
{       
	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;       
}