CBitmap 儲存到檔案

// http://blog.sina.com.cn/s/blog_6ee382440100moeu.html
// http://apps.hi.baidu.com/share/detail/32878068
// bitmap 位圖CBitmap對象指針
// lpFileName 為位圖檔案名  
bool SaveBitmapToFile(CBitmap* bitmap, LPSTR lpFileName)
{            
	HBITMAP hBitmap;	// 為剛才的螢幕位圖句柄
	HDC hDC; //裝置描述表  
	int iBits; //目前顯示分辨率下每個像素所占位元組數  
	WORD wBitCount; //位圖中每個像素所占位元組數	
	DWORD dwPaletteSize = 0, //定義調色闆大小
		dwBmBitsSize,  //位圖中像素位元組大小   
		dwDIBSize,	 //位圖檔案大小
		dwWritten;  //寫入檔案位元組數
	BITMAP Bitmap; //位圖屬性結構  
	BITMAPFILEHEADER bmfHdr; //位圖檔案頭結構  
	BITMAPINFOHEADER bi; //位圖資訊頭結構    
	LPBITMAPINFOHEADER lpbi; //指向位圖資訊頭結構  
	HANDLE fh,	 //定義檔案
		hDib,	 //配置設定記憶體句柄
		hPal,	//調色闆句柄
		hOldPal = NULL;
	
	//計算位圖檔案每個像素所占位元組數  
	hBitmap = (HBITMAP)*bitmap;  
	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 if	(iBits <= 24)  
		wBitCount =	24;  
	else if (iBits <= 32)
		wBitCount = 32;
	
	//計算調色闆大小  
	if (wBitCount <= 8)  
		dwPaletteSize =	(1 << wBitCount) * sizeof (RGBQUAD);
	
	//設定位圖資訊頭結構  
	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.biClrUsed = 0;  
	bi.biClrImportant = 0;  
	
	dwBmBitsSize = ((Bitmap.bmWidth * wBitCount+31) / 32) * 4 * Bitmap.bmHeight;  
	
	//為位圖内容配置設定記憶體  
	hDib = GlobalAlloc(GHND, dwBmBitsSize + dwPaletteSize + sizeof (BITMAPINFOHEADER));  
	lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDib);  
	*lpbi =	bi;
	
	// 處理調色闆 	   
	hPal = GetStockObject(DEFAULT_PALETTE);  
	if (hPal)  
	{  
		hDC = ::GetDC(NULL);	
		hOldPal = ::SelectPalette(hDC, (HPALETTE)hPal, FALSE);	
		RealizePalette(hDC);
	}  
	
	//	 擷取該調色闆下新的像素值  
	GetDIBits(hDC, hBitmap,	0, (UINT) Bitmap.bmHeight,	
		(LPSTR)lpbi + sizeof (BITMAPINFOHEADER)	+ dwPaletteSize,
		(LPBITMAPINFO)lpbi,	DIB_RGB_COLORS);  
	
	//恢複調色闆		
	if (hOldPal)	
	{  
		SelectPalette(hDC, (HPALETTE)hOldPal, TRUE);  
		RealizePalette(hDC);  
		::ReleaseDC(NULL, hDC);
	}  
	
	//建立位圖檔案			
	fh = CreateFile(lpFileName, GENERIC_WRITE,
		0, NULL, CREATE_ALWAYS,
		FILE_ATTRIBUTE_NORMAL |	FILE_FLAG_SEQUENTIAL_SCAN, NULL);  
	
	if (fh == INVALID_HANDLE_VALUE)
		return FALSE;  
	
	//	 設定位圖檔案頭  
	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;	
	
	//	 寫入位圖檔案頭  
	WriteFile(fh, (LPSTR)&bmfHdr, sizeof(BITMAPFILEHEADER), &dwWritten,	NULL);	
	
	//	 寫入位圖檔案其餘内容  
	WriteFile(fh, (LPSTR)lpbi, dwDIBSize,
		&dwWritten, NULL);
	
	//清除		  
	GlobalUnlock(hDib);  
	GlobalFree(hDib);  
	CloseHandle(fh);  

	return TRUE;	
}