dibapi.cpp

K均值聚类算法 C++实现的K均值聚类算法。

	
	// DIB大小
	DWORD dwDIBSize;

	if (hDib == NULL)
	{
		// 如果DIB为空，返回FALSE
		return FALSE;
	}

	// 读取BITMAPINFO结构，并锁定
	lpBI = (LPBITMAPINFOHEADER) ::GlobalLock((HGLOBAL) hDib);
	
	if (lpBI == NULL)
	{
		// 为空，返回FALSE
		return FALSE;
	}
	
	// 判断是否是WIN3.0 DIB
	if (!IS_WIN30_DIB(lpBI))
	{
		// 不支持其它类型的DIB保存
		
		// 解除锁定
		::GlobalUnlock((HGLOBAL) hDib);
		
		// 返回FALSE
		return FALSE;
	}

	// 填充文件头

	// 文件类型"BM"
	bmfHdr.bfType = DIB_HEADER_MARKER;

	// 计算DIB大小时，最简单的方法是调用GlobalSize()函数。但是全局内存大小并
	// 不是DIB真正的大小，它总是多几个字节。这样就需要计算一下DIB的真实大小。
	
	// 文件头大小＋颜色表大小
	// （BITMAPINFOHEADER和BITMAPCOREHEADER结构的第一个DWORD都是该结构的大小）
	dwDIBSize = *(LPDWORD)lpBI + ::PaletteSize((LPSTR)lpBI);
	
	// 计算图像大小
	if ((lpBI->biCompression == BI_RLE8) || (lpBI->biCompression == BI_RLE4))
	{
		// 对于RLE位图，没法计算大小，只能信任biSizeImage内的值
		dwDIBSize += lpBI->biSizeImage;
	}
	else
	{
		// 象素的大小
		DWORD dwBmBitsSize;

		// 大小为Width * Height
		dwBmBitsSize = WIDTHBYTES((lpBI->biWidth)*((DWORD)lpBI->biBitCount)) * lpBI->biHeight;
		
		// 计算出DIB真正的大小
		dwDIBSize += dwBmBitsSize;

		// 更新biSizeImage（很多BMP文件头中biSizeImage的值是错误的）
		lpBI->biSizeImage = dwBmBitsSize;
	}


	// 计算文件大小：DIB大小＋BITMAPFILEHEADER结构大小
	bmfHdr.bfSize = dwDIBSize + sizeof(BITMAPFILEHEADER);
	
	// 两个保留字
	bmfHdr.bfReserved1 = 0;
	bmfHdr.bfReserved2 = 0;

	// 计算偏移量bfOffBits，它的大小为Bitmap文件头大小＋DIB头大小＋颜色表大小
	bmfHdr.bfOffBits = (DWORD)sizeof(BITMAPFILEHEADER) + lpBI->biSize
											  + PaletteSize((LPSTR)lpBI);
	// 尝试写文件
	TRY
	{
		// 写文件头
		file.Write((LPSTR)&bmfHdr, sizeof(BITMAPFILEHEADER));
		
		// 写DIB头和象素
		file.WriteHuge(lpBI, dwDIBSize);
	}
	CATCH (CFileException, e)
	{
		// 解除锁定
		::GlobalUnlock((HGLOBAL) hDib);
		
		// 抛出异常
		THROW_LAST();
	}
	END_CATCH
	
	// 解除锁定
	::GlobalUnlock((HGLOBAL) hDib);
	
	// 返回TRUE
	return TRUE;
}



/************************************************************************* 
 * 
 * SaveDIB() 
 * 
 * Saves the specified DIB into the specified file name on disk.  No 
 * error checking is done, so if the file already exists, it will be 
 * written over. 
 * 
 * Parameters: 
 * 
 * HDIB hDib - Handle to the dib to save 
 * 
 * LPCTSTR lpFileName - pointer to full pathname to save DIB under 
 * 
 * Return value: TRUE if successful
 *				 FALSE if failure
 * 
 *************************************************************************/ 
BOOL SaveDIB(HDIB hDib, LPCTSTR lpFileName) 
{ 
    HANDLE              fh;         // file handle for opened file 
 
    if (!hDib) 
        return FALSE; 
 
    fh = CreateFile(lpFileName, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, 
            FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN, NULL); 
 
    if (fh == INVALID_HANDLE_VALUE) 
        return FALSE; 

	BOOL bSuccess = WriteDIBFile(hDib, fh);

    CloseHandle(fh);
	return bSuccess;
}

/*************************************************************************
*
* 函数名称：
*   ReadDIBFile()
*
* 参数:
*   CFile& file        - 要读取得文件文件CFile
*
* 返回值:
*   HDIB               - 成功返回DIB的句柄，否则返回NULL。
*
* 说明:
*   该函数将指定的文件中的DIB对象读到指定的内存区域中。除BITMAPFILEHEADER
* 外的内容都将被读入内存。
*
*************************************************************************/

HDIB ReadDIBFile(CFile& file)
{
	BITMAPFILEHEADER bmfHeader;
	DWORD dwBitsSize;
	HDIB hDIB;
	LPSTR pDIB;
	
	// 获取DIB（文件）长度（字节）
	dwBitsSize = file.GetLength();
	
	// 尝试读取DIB文件头
	if (file.Read((LPSTR)&bmfHeader, sizeof(bmfHeader)) != sizeof(bmfHeader))
	{
		// 大小不对，返回NULL。
		return NULL;
	}
	
	// 判断是否是DIB对象，检查头两个字节是否是"BM"
	if (bmfHeader.bfType != DIB_HEADER_MARKER)
	{
		// 非DIB对象，返回NULL。
		return NULL;
	}
	
	// 为DIB分配内存
	hDIB = (HDIB) ::GlobalAlloc(GMEM_MOVEABLE | GMEM_ZEROINIT, dwBitsSize);
	if (hDIB == 0)
	{
		// 内存分配失败，返回NULL。
		return NULL;
	}
	
	// 锁定
	pDIB = (LPSTR) ::GlobalLock((HGLOBAL) hDIB);
	
	// 读象素
	if (file.ReadHuge(pDIB, dwBitsSize - sizeof(BITMAPFILEHEADER)) !=
		dwBitsSize - sizeof(BITMAPFILEHEADER) )
	{
		// 大小不对。
		
		// 解除锁定
		::GlobalUnlock((HGLOBAL) hDIB);
		
		// 释放内存
		::GlobalFree((HGLOBAL) hDIB);
		
		// 返回NULL。
		return NULL;
	}
	
	// 解除锁定
	::GlobalUnlock((HGLOBAL) hDIB);
	
	// 返回DIB句柄
	return hDIB;
}
/************************************************************************* 
 * 
 * Function:  ReadDIBFile (HANDLE) 
 * 
 *  Purpose:  Reads in the specified DIB file into a global chunk of 
 *            memory. 
 * 
 *  Returns:  A handle to a dib (hDIB) if successful. 
 *            NULL if an error occurs. 
 * 
 * Comments:  BITMAPFILEHEADER is stripped off of the DIB.  Everything 
 *            from the end of the BITMAPFILEHEADER structure on is 
 *            returned in the global memory handle. 
 * 
 * 
 * NOTE: The DIB API were not written to handle OS/2 DIBs, so this 
 * function will reject any file that is not a Windows DIB. 
 * 
 *************************************************************************/ 
HANDLE ReadDIBFile(HANDLE hFile) 
{ 
    BITMAPFILEHEADER    bmfHeader; 
    DWORD               dwBitsSize; 
    UINT                nNumColors;   // Number of colors in table 
    HANDLE              hDIB;         
    HANDLE              hDIBtmp;      // Used for GlobalRealloc() //MPB 
    LPBITMAPINFOHEADER  lpbi; 
    DWORD               offBits; 
    DWORD               dwRead; 
 
    // get length of DIB in bytes for use when reading 
 
    dwBitsSize = GetFileSize(hFile, NULL); 
 
    // Allocate memory for header & color table. We'll enlarge this 
    // memory as needed. 
 
    hDIB = GlobalAlloc(GMEM_MOVEABLE, (DWORD)(sizeof(BITMAPINFOHEADER) + 
            256 * sizeof(RGBQUAD))); 
 
    if (!hDIB) 
        return NULL; 
 
    lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDIB); 
 
    if (!lpbi)  
    { 
        GlobalFree(hDIB); 
        return NULL; 
    } 
 
    // read the BITMAPFILEHEADER from our file 
 
    if (!ReadFile(hFile, (LPSTR)&bmfHeader, sizeof (BITMAPFILEHEADER), 
            &dwRead, NULL)) 
        goto ErrExit; 
 
    if (sizeof (BITMAPFILEHEADER) != dwRead) 
        goto ErrExit; 
 
    if (bmfHeader.bfType != 0x4d42)  // 'BM' 
        goto ErrExit; 
 
    // read the BITMAPINFOHEADER 
 
    if (!ReadFile(hFile, (LPSTR)lpbi, sizeof(BITMAPINFOHEADER), &dwRead, 
            NULL)) 
        goto ErrExit; 
 
    if (sizeof(BITMAPINFOHEADER) != dwRead) 
        goto ErrExit; 
 
    // Check to see that it's a Windows DIB -- an OS/2 DIB would cause 
    // strange problems with the rest of the DIB API since the fields 
    // in the header are different and the color table entries are 
    // smaller. 
    // 
    // If it's not a Windows DIB (e.g. if biSize is wrong), return NULL. 
 
    if (lpbi->biSize == sizeof(BITMAPCOREHEADER)) 
        goto ErrExit; 
 
    // Now determine the size of the color table and read it.  Since the 
    // bitmap bits are offset in the file by bfOffBits, we need to do some 
    // special processing here to make sure the bits directly follow 
    // the color table (because that's the format we are susposed to pass 
    // back) 
 
    if (!(nNumColors = (UINT)lpbi->biClrUsed)) 
    { 
        // no color table for 24-bit, default size otherwise 
 
        if (lpbi->biBitCount > 8)	//(lpbi->biBitCount != 24) 
            nNumColors = 1 << lpbi->biBitCount; // standard size table 
    } 
 
    // fill in some default values if they are zero 
 
    if (lpbi->biClrUsed == 0) 
        lpbi->biClrUsed = nNumColors; 
 
    if (lpbi->biSizeImage == 0) 
    { 
        lpbi->biSizeImage = ((((lpbi->biWidth * (DWORD)lpbi->biBitCount) + 
                31) & ~31) >> 3) * lpbi->biHeight; 
    } 
 
    // get a proper-sized buffer for header, color table and bits 
 
    GlobalUnlock(hDIB); 
    hDIBtmp = GlobalReAlloc(hDIB, lpbi->biSize + nNumColors * 
            sizeof(RGBQUAD) + lpbi->biSizeImage, 0); 
 
    if (!hDIBtmp) // can't resize buffer for loading 
        goto ErrExitNoUnlock; //MPB 
    else 
        hDIB = hDIBtmp; 
 
    lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDIB); 
 
    // read the color table 
 
    ReadFile (hFile, (LPSTR)(lpbi) + lpbi->biSize, 
            nNumColors * sizeof(RGBQUAD), &dwRead, NULL); 
 
    // offset to the bits from start of DIB header 
 
    offBits = lpbi->biSize + nNumColors * sizeof(RGBQUAD); 
 
    // If the bfOffBits field is non-zero, then the bits might *not* be 
    // directly following the color table in the file.  Use the value in 
    // bfOffBits to seek the bits. 
 
    if (bmfHeader.bfOffBits != 0L) 
        SetFilePointer(hFile, bmfHeader.bfOffBits, NULL, FILE_BEGIN); 
 
    if (ReadFile(hFile, (LPSTR)lpbi + offBits, lpbi->biSizeImage, &dwRead, 
            NULL)) 
        goto OKExit; 
 
ErrExit: 
    GlobalUnlock(hDIB);     
 
ErrExitNoUnlock:     
    GlobalFree(hDIB); 
    return NULL; 
 
OKExit: 
    GlobalUnlock(hDIB); 
    return hDIB; 
} 
 
/************************************************************************* 
 * 
 * Function:  WriteDIBFile (HANDLE, int) 
 * 
 *  Purpose:  Writes a global chunk of DIB memory to specified file 
 * 
 *  Returns:  TRUE if success, else FALSE
 * 
 * Comments:  BITMAPFILEHEADER is stripped off of the DIB.  Everything 
 *            from the end of the BITMAPFILEHEADER structure on is 
 *            returned in the global memory handle. 
 * 
 * 
 * NOTE: The DIB API were not written to handle OS/2 DIBs, so this 
 * function will reject any file that is not a Windows DIB. 
 * 
 *************************************************************************/ 
BOOL WriteDIBFile(HDIB hDib, HANDLE fh) 
{ 
    BITMAPFILEHEADER    bmfHdr;     // Header for Bitmap file 
    LPBITMAPINFOHEADER  lpBI;       // Pointer to DIB info structure 
    DWORD               dwDIBSize; 
    DWORD               dwWritten; 

    if (!hDib) 
        return FALSE; 

    // Get a pointer to the DIB memory, the first of which contains 
    // a BITMAPINFO structure 
 
    lpBI = (LPBITMAPINFOHEADER)GlobalLock(hDib); 
    if (!lpBI) 
    { 
        CloseHandle(fh); 
        return FALSE; 
    } 
 
    // Check to see if we're dealing with an OS/2 DIB.  If so, don't 
    // save it because our functions aren't written to deal with these 
    // DIBs. 
 
    if (lpBI->biSize != sizeof(BITMAPINFOHEADER)) 
    { 
        GlobalUnlock(hDib); 
        CloseHandle(fh); 
        return FALSE; 
    } 
 
    // Fill in the fields of the file header 
 
    // Fill in file type (first 2 bytes must be "BM" for a bitmap)