Save HBITMAP to *.bmp file using only Win32

Question

I have a HBITMAP in my pure Win32 project (no external libraries are used). Can I export it to a *.bmp file using only Winapi and/or CRT functions so I don\'t incur any extr

Answer 1

One function code for 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;
}