Sample Code - Save HBITMAP To BMP File

[C++] Save HBITMAP To BMP File
BOOL SaveHBITMAPToFile(HBITMAP hBitmap, LPCTSTR lpszFileName)
{
	HDC hDC;
	int iBits;
	WORD wBitCount;
	DWORD dwPaletteSize = 0, dwBmBitsSize = 0, dwDIBSize = 0, dwWritten = 0;
	BITMAP Bitmap0;
	BITMAPFILEHEADER bmfHdr;
	BITMAPINFOHEADER bi;
	LPBITMAPINFOHEADER lpbi;
	HANDLE fh, hDib, hPal, hOldPal2 = NULL;
	hDC = CreateDC(TEXT("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(Bitmap0), (LPSTR)&Bitmap0);
	bi.biSize = sizeof(BITMAPINFOHEADER);
	bi.biWidth = Bitmap0.bmWidth;
	bi.biHeight = -Bitmap0.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 = 256;
	dwBmBitsSize = ((Bitmap0.bmWidth * wBitCount + 31) & ~31) / 8
		* Bitmap0.bmHeight;
	hDib = GlobalAlloc(GHND, dwBmBitsSize + dwPaletteSize + sizeof(BITMAPINFOHEADER));
	lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDib);
	*lpbi = bi;

	hPal = GetStockObject(DEFAULT_PALETTE);
	if (hPal)
	{
		hDC = GetDC(NULL);
		hOldPal2 = SelectPalette(hDC, (HPALETTE)hPal, FALSE);
		RealizePalette(hDC);
	}


	GetDIBits(hDC, hBitmap, 0, (UINT)Bitmap0.bmHeight, (LPSTR)lpbi + sizeof(BITMAPINFOHEADER)
		+ dwPaletteSize, (BITMAPINFO *)lpbi, DIB_RGB_COLORS);

	if (hOldPal2)
	{
		SelectPalette(hDC, (HPALETTE)hOldPal2, TRUE);
		RealizePalette(hDC);
		ReleaseDC(NULL, hDC);
	}

	fh = CreateFile(lpszFileName, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS,
		FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN, NULL);

	if (fh == INVALID_HANDLE_VALUE)
		return FALSE;

	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;

	WriteFile(fh, (LPSTR)&bmfHdr, sizeof(BITMAPFILEHEADER), &dwWritten, NULL);

	WriteFile(fh, (LPSTR)lpbi, dwDIBSize, &dwWritten, NULL);
	GlobalUnlock(hDib);
	GlobalFree(hDib);
	CloseHandle(fh);
	return TRUE;
}