保存MFC的CBitmap对象中的图象到一个BMP文件中

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BOOL SaveBmp(HBITMAP hBitmap, CString FileName) //FileName包括路径和文件的全名

//hBitmap=（HBITMAP ）bm.GetSafeHandle();    CBitmap bm;

{

//设备描述表

HDC hDC;

//当前分辨率下每象素所占字节数

int iBits;

//位图中每象素所占字节数

WORD wBitCount;

//定义调色板大小， 位图中像素字节大小 ，位图文件大小 ， 写入文件字节数

DWORD dwPaletteSize=0, dwBmBitsSize=0, dwDIBSize=0, dwWritten=0;

//位图属性结构

BITMAP Bitmap;  

//位图文件头结构

BITMAPFILEHEADER bmfHdr;  

//位图信息头结构

BITMAPINFOHEADER bi;  

//指向位图信息头结构  

LPBITMAPINFOHEADER lpbi;  

//定义文件，分配内存句柄，调色板句柄

HANDLE fh, hDib, hPal,hOldPal=NULL;

//计算位图文件每个像素所占字节数

hDC = CreateDC("DISPLAY", NULL, NULL, NULL);

iBits = GetDeviceCaps(hDC, BITSPIXEL) * GetDeviceCaps(hDC, PLANES);

DeleteDC(hDC);

if (iBits <= 1) wBitCount = 1;

else if (iBits <= 4) wBitCount = 4;

else if (iBits <= 8) wBitCount = 8;

else wBitCount = 24;

GetObject(hBitmap, sizeof(Bitmap), (LPSTR)&Bitmap);

bi.biSize = sizeof(BITMAPINFOHEADER);

bi.biWidth = Bitmap.bmWidth;

bi.biHeight = Bitmap.bmHeight;

bi.biPlanes = 1;

bi.biBitCount = wBitCount;

bi.biCompression = BI_RGB;

bi.biSizeImage = 0;

bi.biXPelsPerMeter = 0;

bi.biYPelsPerMeter = 0;

bi.biClrImportant = 0;

bi.biClrUsed = 0;

dwBmBitsSize = ((Bitmap.bmWidth * wBitCount + 31) / 32) * 4 * Bitmap.bmHeight;

//为位图内容分配内存

hDib = GlobalAlloc(GHND,dwBmBitsSize + dwPaletteSize + sizeof(BITMAPINFOHEADER));

lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDib);

*lpbi = bi;

// 处理调色板  

hPal = GetStockObject(DEFAULT_PALETTE);

if (hPal)

{

hDC = ::GetDC(NULL);

hOldPal = ::SelectPalette(hDC, (HPALETTE)hPal, FALSE);

RealizePalette(hDC);

}

// 获取该调色板下新的像素值

GetDIBits(hDC, hBitmap, 0, (UINT) Bitmap.bmHeight, (LPSTR)lpbi + sizeof(BITMAPINFOHEADER)

+dwPaletteSize, (BITMAPINFO *)lpbi, DIB_RGB_COLORS);

//恢复调色板  

if (hOldPal)

{

::SelectPalette(hDC, (HPALETTE)hOldPal, TRUE);

RealizePalette(hDC);

::ReleaseDC(NULL, hDC);

}

//创建位图文件  

fh = CreateFile(FileName, GENERIC_WRITE,0, NULL, CREATE_ALWAYS,

FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN, NULL);

if (fh == INVALID_HANDLE_VALUE)   return FALSE;

// 设置位图文件头

bmfHdr.bfType = 0x4D42; // "BM"

dwDIBSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + dwPaletteSize + dwBmBitsSize;  

bmfHdr.bfSize = dwDIBSize;

bmfHdr.bfReserved1 = 0;

bmfHdr.bfReserved2 = 0;

bmfHdr.bfOffBits = (DWORD)sizeof(BITMAPFILEHEADER) + (DWORD)sizeof(BITMAPINFOHEADER) + dwPaletteSize;

// 写入位图文件头

WriteFile(fh, (LPSTR)&bmfHdr, sizeof(BITMAPFILEHEADER), &dwWritten, NULL);

// 写入位图文件其余内容

// WriteFile(fh, (LPSTR)lpbi, dwDIBSize, &dwWritten, NULL);

//清除  

GlobalUnlock(hDib);

GlobalFree(hDib);

CloseHandle(fh);

return TRUE;

}