cdib.cpp

把一个图象转 换为灰度图换为灰度图

	::DeleteObject(hBitmap);
	Empty();
	m_nBmihAlloc = m_nImageAlloc = crtAlloc;
	m_lpBMIH = lpBMIH;
	m_lpImage = lpImage;
	ComputeMetrics();
	ComputePaletteSize(m_lpBMIH->biBitCount);
	MakePalette();
	::SelectPalette(hdc, hOldPalette, FALSE);
	TRACE("Compress: new palette size = %d\n", m_nColorTableEntries); 
	return TRUE;
}

BOOL CDib::Read(CFile* pFile)
{
	// 1. read file header to get size of info hdr + color table
	// 2. read info hdr (to get image size) and color table
	// 3. read image
	// can't use bfSize in file header
	Empty();
	int nCount, nSize;
	BITMAPFILEHEADER bmfh;
	try {
		nCount = pFile->Read((LPVOID) &bmfh, sizeof(BITMAPFILEHEADER));
		if(nCount != sizeof(BITMAPFILEHEADER)) {
			throw new CException;
		}
		if(bmfh.bfType != 0x4d42) {
			throw new CException;
		}
		nSize = bmfh.bfOffBits - sizeof(BITMAPFILEHEADER);
		m_lpBMIH = (LPBITMAPINFOHEADER) new char[nSize];
		m_nBmihAlloc = m_nImageAlloc = crtAlloc;
		nCount = pFile->Read(m_lpBMIH, nSize); // info hdr & color table
		ComputeMetrics();
		ComputePaletteSize(m_lpBMIH->biBitCount);
		MakePalette();
		m_lpImage = (LPBYTE) new char[m_dwSizeImage];
		nCount = pFile->Read(m_lpImage, m_dwSizeImage); // image only
	}
	catch(CException* pe) {
		AfxMessageBox("Read error");
		pe->Delete();
		return FALSE;
	}
	return TRUE;
}
//____________________________________________________________
BOOL CDib::Read(char* FileName)
{
	// 1. read file header to get size of info hdr + color table
	// 2. read info hdr (to get image size) and color table
	// 3. read image
	// can't use bfSize in file header
	CFile *pFile;
	pFile=new CFile();
	pFile->Open(FileName, CFile::modeRead);

	Read(pFile);

	pFile->Close();
	delete pFile;
	return TRUE;
}
//________________________________________________________________
BOOL CDib::ReadSection(CFile* pFile, CDC* pDC /* = NULL */)
{
	// new function reads BMP from disk and creates a DIB section
	//    allows modification of bitmaps from disk
	// 1. read file header to get size of info hdr + color table
	// 2. read info hdr (to get image size) and color table
	// 3. create DIB section based on header parms
	// 4. read image into memory that CreateDibSection allocates
	Empty();
	int nCount, nSize;
	BITMAPFILEHEADER bmfh;
	try {
		nCount = pFile->Read((LPVOID) &bmfh, sizeof(BITMAPFILEHEADER));
		if(nCount != sizeof(BITMAPFILEHEADER)) {
			throw new CException;
		}
		if(bmfh.bfType != 0x4d42) {
			throw new CException;
		}
		nSize = bmfh.bfOffBits - sizeof(BITMAPFILEHEADER);
		m_lpBMIH = (LPBITMAPINFOHEADER) new char[nSize];
		m_nBmihAlloc = crtAlloc;
		m_nImageAlloc = noAlloc;
		nCount = pFile->Read(m_lpBMIH, nSize); // info hdr & color table
		if(m_lpBMIH->biCompression != BI_RGB) {
			throw new CException;
		}
		ComputeMetrics();
		ComputePaletteSize(m_lpBMIH->biBitCount);
		MakePalette();
		UsePalette(pDC);
		m_hBitmap = ::CreateDIBSection(pDC->GetSafeHdc(), (LPBITMAPINFO) m_lpBMIH,
			DIB_RGB_COLORS,	(LPVOID*) &m_lpImage, NULL, 0);
		ASSERT(m_lpImage != NULL);
		nCount = pFile->Read(m_lpImage, m_dwSizeImage); // image only
	}
	catch(CException* pe) {
		AfxMessageBox("ReadSection error");
		pe->Delete();
		return FALSE;
	}
	return TRUE;
}

BOOL CDib::Write(CFile* pFile)
{
	BITMAPFILEHEADER bmfh;
	bmfh.bfType = 0x4d42;  // 'BM'
	int nSizeHdr = sizeof(BITMAPINFOHEADER) + sizeof(RGBQUAD) * m_nColorTableEntries;
	bmfh.bfSize = 0;
//	bmfh.bfSize = sizeof(BITMAPFILEHEADER) + nSizeHdr + m_dwSizeImage;
	// meaning of bfSize open to interpretation (bytes, words, dwords?) -- we won't use it
	bmfh.bfReserved1 = bmfh.bfReserved2 = 0;
	bmfh.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) +
			sizeof(RGBQUAD) * m_nColorTableEntries;	
	try {
		pFile->Write((LPVOID) &bmfh, sizeof(BITMAPFILEHEADER));
		pFile->Write((LPVOID) m_lpBMIH,  nSizeHdr);
		pFile->Write((LPVOID) m_lpImage, m_dwSizeImage);
	}
	catch(CException* pe) {
		pe->Delete();
		AfxMessageBox("write error");
		return FALSE;
	}
	return TRUE;
}
//__________________________________________________________
BOOL CDib::Write(char* FileName)
{
	CFile *fp;
	fp=new CFile();
	fp->Open(FileName, CFile::modeCreate|CFile::modeWrite);
	Write(fp);
	fp->Close();
	delete fp;
	return TRUE;
}
//________________________________________________________________
void CDib::Serialize(CArchive& ar)
{
	DWORD dwPos;
	dwPos = ar.GetFile()->GetPosition();
	TRACE("CDib::Serialize -- pos = %d\n", dwPos);
	ar.Flush();
	dwPos = ar.GetFile()->GetPosition();
	TRACE("CDib::Serialize -- pos = %d\n", dwPos);
	if(ar.IsStoring()) {
		Write(ar.GetFile());
	}
	else {
		Read(ar.GetFile());
	}
}

// helper functions
void CDib::ComputePaletteSize(int nBitCount)
{
	if((m_lpBMIH == NULL) || (m_lpBMIH->biClrUsed == 0)) {
		switch(nBitCount) {
			case 1:
				m_nColorTableEntries = 2;
				break;
			case 4:
				m_nColorTableEntries = 16;
				break;
			case 8:
				m_nColorTableEntries = 256;
				break;
			case 16:
			case 24:
			case 32:
				m_nColorTableEntries = 0;
				break;
			default:
				ASSERT(FALSE);
		}
	}
	else {
		m_nColorTableEntries = m_lpBMIH->biClrUsed;
	}
	ASSERT((m_nColorTableEntries >= 0) && (m_nColorTableEntries <= 256)); 
}

void CDib::ComputeMetrics()
{
	if(m_lpBMIH->biSize != sizeof(BITMAPINFOHEADER))
	{
		TRACE("Not a valid Windows bitmap -- probably an OS/2 bitmap\n");
		throw new CException;
	}
	m_dwSizeImage = m_lpBMIH->biSizeImage;
	if(m_dwSizeImage == 0) 
	{
		DWORD dwBytes = ((DWORD) m_lpBMIH->biWidth * m_lpBMIH->biBitCount) / 32;
		if(((DWORD) m_lpBMIH->biWidth * m_lpBMIH->biBitCount) % 32)
		{
			dwBytes++;
		}
		dwBytes *= 4;
		m_dwSizeImage = dwBytes * m_lpBMIH->biHeight; // no compression
	}
	m_lpvColorTable = (LPBYTE) m_lpBMIH + sizeof(BITMAPINFOHEADER);
}

void CDib::Empty()
{
	// this is supposed to clean up whatever is in the DIB
	DetachMapFile();
	if(m_nBmihAlloc == crtAlloc) {
		delete [] m_lpBMIH;
	}
	else if(m_nBmihAlloc == heapAlloc) {
		::GlobalUnlock(m_hGlobal);
		::GlobalFree(m_hGlobal);
	}
	if(m_nImageAlloc == crtAlloc) delete [] m_lpImage;
	if(m_hPalette != NULL) ::DeleteObject(m_hPalette);
	if(m_hBitmap != NULL) ::DeleteObject(m_hBitmap);
	m_nBmihAlloc = m_nImageAlloc = noAlloc;
	m_hGlobal = NULL;
	m_lpBMIH = NULL;
	m_lpImage = NULL;
	m_lpvColorTable = NULL;
	m_nColorTableEntries = 0;
	m_dwSizeImage = 0;
	m_lpvFile = NULL;
	m_hMap = NULL;
	m_hFile = NULL;
	m_hBitmap = NULL;
	m_hPalette = NULL;
}

void CDib::DetachMapFile()
{
	if(m_hFile == NULL) return;
	::UnmapViewOfFile(m_lpvFile);
	::CloseHandle(m_hMap);
	::CloseHandle(m_hFile);
	m_hFile = NULL;
}
//=================================================================
Image* CDib::DibToImage()
{
	int i,j;
	int width;
	if (m_lpBMIH->biWidth%4)
		width=(m_lpBMIH->biWidth/4)*4+4;
	else
		width=m_lpBMIH->biWidth;
	Image* im=new Image(width, m_lpBMIH->biHeight);
	Image* im0=new Image(m_lpBMIH->biWidth, m_lpBMIH->biHeight);

	for (j=0;j<im->height;j++)
	{
		for (i=0; i<im->width;i++)
		{
			im->ng[i][j]=m_lpImage[(im->height-1-j)*im->width+i];
		}
	}
	
	for (j=0;j<im0->height;j++)
	{
		for (i=0; i<im0->width;i++)
		{
			im0->ng[i][j]=im->ng[i][j];
		}
	}
	delete im;
	return im0;
}
//=================================================================
void CDib::DibToImage(Image *im)
{
	int i,j;
	int width;
	if (m_lpBMIH->biWidth%4)
		width=(m_lpBMIH->biWidth/4)*4+4;
	else
		width=m_lpBMIH->biWidth;

	im->width=m_lpBMIH->biWidth;
	im->height=m_lpBMIH->biHeight;
	Image* im0=new Image(width, m_lpBMIH->biHeight);

	for (j=0;j<im0->height;j++)
	{
		for (i=0; i<im0->width;i++)
		{
			im0->ng[i][j]=m_lpImage[(im->height-1-j)*im->width+i];
		}
	}
	
	for (j=0;j<im->height;j++)
	{
		for (i=0; i<im->width;i++)
		{
			im->ng[i][j]=im0->ng[i][j];
		}
	}
	delete im0;
}
//==================================================================
void CDib::ImageToDib(Image* im)
{	
	int i,j;
	int width;

	if (im->width%4)
		width=(im->width/4)*4+4;
	else
		width=im->width;

	m_lpBMIH->biWidth=width;
	m_lpBMIH->biHeight=im->height;

/*	if (m_lpBMIH->biWidth%4)
		width=(m_lpBMIH->biWidth/4)*4+4;
	else
		width=m_lpBMIH->biWidth;
*/
	Image *im0=new Image(width, m_lpBMIH->biHeight);

	for (j=0;j<im->height;j++)
	{
		for (i=0; i<im->width;i++)
		{
			im0->ng[i][j]=im->ng[i][j];
		}
	}

	for (j=0;j<im0->height;j++)
	{
		for (i=0; i<im0->width;i++)
		{
			m_lpImage[(im0->height-1-j)*im0->width+i]=im0->ng[i][j];
		}
	}

	delete im0;
}
//=================================================================