将位图写入磁盘

void WriteBMPFile(HBITMAP hBitmap, LPSTR filename, HDC hDC)
{
 BITMAP bmp; 
    PBITMAPINFO pbmi; 
    WORD cClrBits; 
    HANDLE hf; // file handle 
    BITMAPFILEHEADER hdr; // bitmap file-header 
    PBITMAPINFOHEADER pbih; // bitmap info-header 
    LPBYTE lpBits; // memory pointer 
    DWORD dwTotal; // total count of bytes 
    DWORD cb; // incremental count of bytes 
    BYTE *hp; // byte pointer 
    DWORD dwTmp; 
    // create the bitmapinfo header information

    if (!GetObject( hBitmap, sizeof(BITMAP), (LPTSTR)&bmp))
    {
        return;
    }

    // Convert the color format to a count of bits. 

    cClrBits = (WORD)(bmp.bmPlanes * bmp.bmBitsPixel); 

    if (cClrBits == 1) 
  cClrBits = 1; 
    else if (cClrBits <= 4) 
    cClrBits = 4; 
    else if (cClrBits <= 8) 
    cClrBits = 8; 
    else if (cClrBits <= 16) 
   cClrBits = 16; 
    else if (cClrBits <= 24) 
      cClrBits = 24; 
    else cClrBits = 32; 

    // Allocate memory for the BITMAPINFO structure.

    if (cClrBits != 24) 
    pbmi = (PBITMAPINFO) LocalAlloc(LPTR, sizeof(BITMAPINFOHEADER) + sizeof(RGBQUAD) * (1<<cClrBits)); 
    else 
    pbmi = (PBITMAPINFO) LocalAlloc(LPTR, sizeof(BITMAPINFOHEADER)); 
  // Initialize the fields in the BITMAPINFO structure. 

    pbmi->bmiHeader.biSize = sizeof(BITMAPINFOHEADER); 
    pbmi->bmiHeader.biWidth = bmp.bmWidth; 
    pbmi->bmiHeader.biHeight = bmp.bmHeight; 
    pbmi->bmiHeader.biPlanes = bmp.bmPlanes; 
    pbmi->bmiHeader.biBitCount = bmp.bmBitsPixel; 

    if (cClrBits < 24) 
  pbmi->bmiHeader.biClrUsed = (1 <<cClrBits); 

 

    // If the bitmap is not compressed, set the BI_RGB flag. 
    pbmi->bmiHeader.biCompression = BI_RGB; 

    // Compute the number of bytes in the array of color 

    // indices and store the result in biSizeImage. 
    pbmi->bmiHeader.biSizeImage = (pbmi->bmiHeader.biWidth + 7) /8 * pbmi->bmiHeader.biHeight * cClrBits; 

    // Set biClrImportant to 0, indicating that all of the 

    // device colors are important. 
    pbmi->bmiHeader.biClrImportant = 0; 

    // now open file and save the data
    pbih = (PBITMAPINFOHEADER) pbmi; 
    lpBits = (LPBYTE) GlobalAlloc(GMEM_FIXED, pbih->biSizeImage);

    if (!lpBits) 
    {
        return;
    }

    // Retrieve the color table (RGBQUAD array) and the bits 

    if (!GetDIBits(hDC, HBITMAP(hBitmap), 0, (WORD) pbih->biHeight, lpBits, pbmi, DIB_RGB_COLORS))
    {
        return;
    }

    // Create the .BMP file. 

    hf = CreateFile(filename, GENERIC_READ | GENERIC_WRITE, (DWORD) 0, 
                    NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, 
                    (HANDLE) NULL); 

    if (hf == INVALID_HANDLE_VALUE)  return; 

    hdr.bfType = 0x4d42; // 0x42 = "B" 0x4d = "M" 

    // Compute the size of the entire file. 
    hdr.bfSize = (DWORD) (sizeof(BITMAPFILEHEADER) + pbih->biSize + pbih->biClrUsed  * sizeof(RGBQUAD) + pbih->biSizeImage); 
    hdr.bfReserved1 = 0; 
    hdr.bfReserved2 = 0; 

    // Compute the offset to the array of color indices. 
    hdr.bfOffBits = (DWORD) sizeof(BITMAPFILEHEADER) + 
                    pbih->biSize + pbih->biClrUsed  * sizeof (RGBQUAD); 

    // Copy the BITMAPFILEHEADER into the .BMP file. 
    if (!WriteFile(hf, (LPVOID) &hdr, sizeof(BITMAPFILEHEADER), (LPDWORD) &dwTmp, NULL)) 
    {
        return;
    }

    // Copy the BITMAPINFOHEADER and RGBQUAD array into the file. 
    if (!WriteFile(hf, (LPVOID) pbih, sizeof(BITMAPINFOHEADER) + pbih->biClrUsed * sizeof (RGBQUAD),    (LPDWORD) &dwTmp, ( NULL)))
    {
       return;
    }

    // Copy the array of color indices into the .BMP file. 
    dwTotal = cb = pbih->biSizeImage; 
    hp = lpBits; 
    if (!WriteFile(hf, (LPSTR) hp, (int) cb, (LPDWORD) &dwTmp,NULL))
    {
        return;
    }

    // Close the .BMP file. 
    if (!CloseHandle(hf))
    {
        return;
    }

    // Free memory. 

    GlobalFree((HGLOBAL)lpBits);
}

 

 

测试代码：

void OnDraw(CDC* pDC)
{
 CTestBMPDoc* pDoc = GetDocument();
 ASSERT_VALID(pDoc);
 // TODO: add draw code for native data here

 CRect rect;
 GetClientRect(&rect);
 
 CDC ImageDC;  
    ImageDC.CreateCompatibleDC(pDC);
 
 CBitmap bmp,*oldbmp;  
 bmp.CreateCompatibleBitmap(pDC,rect.Width(),rect.Height());
 oldbmp = ImageDC.SelectObject(&bmp);
 
    ImageDC.FillSolidRect(rect, pDC->GetBkColor());
 
 ImageDC.MoveTo(10, 10);
 ImageDC.LineTo(300, 300);
 
 WriteBMPFile((HBITMAP)bmp.GetSafeHandle(),"C://1.bmp",ImageDC.m_hDC);
 
 pDC->BitBlt(0,0,rect.Width(),rect.Height(),&ImageDC,0,0,SRCCOPY);

 ImageDC.SelectObject(oldbmp);
 
 ImageDC.DeleteDC();
}