How can I create .bmp file from HBITMAP?

Last Updated on Monday, 31 May 2010 08:35 Written by Simeon Antonov
Attention: open in a new window.
I get this code from MSDN and make a few changes.
(HBITMAP to bmp)
 
PBITMAPINFO CreateBitmapInfoStruct(HBITMAP hBmp)
{ 
 BITMAP bmp; 
 PBITMAPINFO pbmi; 
 WORD    cClrBits;
 // Retrieve the bitmap color format, width, and height. 
 if (!GetObject(hBmp, sizeof(BITMAP), (LPSTR)&amp;bmp)) 
 return NULL;
 
 // 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. (This structure 
 // contains a BITMAPINFOHEADER structure and an array of RGBQUAD 
 // data structures.) 
 
 if (cClrBits != 24) 
 pbmi = (PBITMAPINFO) LocalAlloc(LPTR, 
 sizeof(BITMAPINFOHEADER) + 
 sizeof(RGBQUAD) * (1<< cClrBits)); 
 
 // There is no RGBQUAD array for the 24-bit-per-pixel format. 
 
 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. 
 // For Windows NT, the width must be DWORD aligned unless 
 // the bitmap is RLE compressed. This example shows this. 
 // For Windows 95/98/Me, the width must be WORD aligned unless the 
 // bitmap is RLE compressed.
 pbmi->bmiHeader.biSizeImage = ((pbmi->bmiHeader.biWidth * cClrBits +31) &amp; ~31) /8
 * pbmi->bmiHeader.biHeight; 
 // Set biClrImportant to 0, indicating that all of the 
 // device colors are important. 
 pbmi->bmiHeader.biClrImportant = 0; 
 return pbmi; 
} 
 
void CreateBMPFile(LPTSTR pszFile, PBITMAPINFO pbi, 
 HBITMAP hBMP, HDC hDC) 
{ 
 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; 
 
 pbih = (PBITMAPINFOHEADER) pbi; 
 lpBits = (LPBYTE) GlobalAlloc(GMEM_FIXED, pbih->biSizeImage);
 
 if (!lpBits) 
 return; 
 
 // Retrieve the color table (RGBQUAD array) and the bits 
 // (array of palette indices) from the DIB. 
 if (!GetDIBits(hDC, hBMP, 0, (WORD) pbih->biHeight, lpBits, pbi, 
 DIB_RGB_COLORS)) 
 {
 return;
 }
 
 // Create the .BMP file. 
 hf = CreateFile(pszFile, 
 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) &amp;hdr, sizeof(BITMAPFILEHEADER), 
 (LPDWORD) &amp;dwTmp,  NULL)) 
 {
 return; 
 }
 
 // Copy the BITMAPINFOHEADER and RGBQUAD array into the file. 
 if (!WriteFile(hf, (LPVOID) pbih, sizeof(BITMAPINFOHEADER) 
 + pbih->biClrUsed * sizeof (RGBQUAD), 
 (LPDWORD) &amp;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) &amp;dwTmp,NULL)) 
 return; 
 
 // Close the .BMP file. 
 if (!CloseHandle(hf)) 
 return; 
 
 // Free memory. 
 GlobalFree((HGLOBAL)lpBits);
}
 
 
//code for saving bitmap
HBITMAP hBitmap;
HDC hdc;
...
PBITMAPINFO pBitmapInfo = CreateBitmapInfoStruct(hBitmap);
CreateBMPFile(_T("c:\\temp\\picture.bmp"), pBitmapInfo, hBitmap, hdc);
 © www.sas.bg
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