Writing a bitmap to a BMP file


Writing a bitmap to a BMP file is fairly simple if we have a handle to device-independent bitmap. We simply write BITMAPINFOHEADER information followed by the contents of the bitmap. The three fields that we have to set in the BITMAPINFOHEADER are the bfType which should always be "BM", the bfSize which is the size of the bitmap including the infoheader and the bfOffBits which is the offset to the bitmap bits from the start of the file.

If you have a device-dependent bitmap to begin with, you have to first create a DIB from it. Creating a DIB from a DDB has already been covered in another section.

// WriteDIB		- Writes a DIB to file
// Returns		- TRUE on success
// szFile		- Name of file to write to
// hDIB			- Handle of the DIB
BOOL WriteDIB( LPTSTR szFile, HANDLE hDIB)
{
	BITMAPFILEHEADER	hdr;
	LPBITMAPINFOHEADER	lpbi;

	if (!hDIB)
		return FALSE;

	CFile file;
	if( !file.Open( szFile, CFile::modeWrite|CFile::modeCreate) )
		return FALSE;

	lpbi = (LPBITMAPINFOHEADER)hDIB;

	int nColors = 1 << lpbi->biBitCount;

	// Fill in the fields of the file header 
	hdr.bfType		= ((WORD) ('M' << 8) | 'B');	// is always "BM"
	hdr.bfSize		= GlobalSize (hDIB) + sizeof( hdr );
	hdr.bfReserved1 	= 0;
	hdr.bfReserved2 	= 0;
	hdr.bfOffBits		= (DWORD) (sizeof( hdr ) + lpbi->biSize +
						nColors * sizeof(RGBQUAD));

	// Write the file header 
	file.Write( &hdr, sizeof(hdr) );

	// Write the DIB header and the bits 
	file.Write( lpbi, GlobalSize(hDIB) );

	return TRUE;
}



Comments

  • There are no comments yet. Be the first to comment!

Leave a Comment
  • Your email address will not be published. All fields are required.

Top White Papers and Webcasts

  • Today's agile organizations pose operations teams with a tremendous challenge: to deploy new releases to production immediately after development and testing is completed. To ensure that applications are deployed successfully, an automatic and transparent process is required. We refer to this process as Zero Touch Deployment™. This white paper reviews two approaches to Zero Touch Deployment--a script-based solution and a release automation platform. The article discusses how each can solve the key …

  • Companies undertaking an IT project need to find the right balance between cost and functionality. It's important to start by determining whether to build a solution from scratch, buy an out-of-the-box solution, or a combination of both. In reality, most projects will require some system tailoring to meet business requirements. Decision-makers must understand how much software development is enough and craft a detailed implementation plan to ensure the project's success. This white paper examines the different …

Most Popular Programming Stories

More for Developers

RSS Feeds

Thanks for your registration, follow us on our social networks to keep up-to-date