MFC 屏幕截圖方法

//獲取當前屏幕的而且保存圖片
LRESULT CFeetScanView::SaveViewBMP(WPARAM wParam, LPARAM lParam)
{
    CRect rect;
    this->GetClientRect(&rect);
    rect.left = 20;
    rect.top = 80;
    CBitmap m_bitmap;
    m_bitmap.m_hObject = CopyScreenToBitmap(rect);

    char szFileName[_MAX_PATH];
    char szPath[_MAX_PATH];
    GetConfigMgr()->GetModuleDirectory( szPath);
    sprintf( szFileName, "%s\\image.png", szPath);
    SaveBitmapToFile(m_bitmap,szFileName);
    return 0;
}


HBITMAP CFeetScanView::CopyScreenToBitmap(LPRECT lpRect) 
{ 
   // 屏幕和內存設備描述表 
    HDC hScrDC=0, hMemDC; 
    // 位圖句柄 
    HBITMAP hBitmap, hOldBitmap; 
    // 選定區域座標 
    int nX, nY, nX2, nY2; 
    // 位圖寬度和高度 
    int nWidth, nHeight; 
    // 屏幕分辨率 
    int xScrn, yScrn;     
    // 確保選定區域不爲空矩形 
    // if (IsRectEmpty(lpRect)) 
    // return NULL; 
    //爲屏幕建立設備描述表 
    hScrDC = CreateDC( "DISPLAY", NULL, NULL, NULL); 
    //
    int ok=1; 
    if(hScrDC==NULL)  //若是建立失敗
    {    
        ok=0;
    }
    //爲屏幕設備描述表建立兼容的內存設備描述表 
    hMemDC = CreateCompatibleDC(hScrDC);     
    // 得到選定區域座標 
    nX = lpRect-> left; 
    nY = lpRect-> top; 
    nX2 = lpRect-> right; 
    nY2 = lpRect-> bottom; 
    // 得到屏幕分辨率 
    xScrn = GetDeviceCaps(hScrDC, HORZRES); 
    yScrn = GetDeviceCaps(hScrDC, VERTRES); 
    //確保選定區域是可見的 
    if (nX <0) 
        nX = 0; 
    if (nY < 0) 
        nY = 0; 
    if (nX2 > xScrn) 
        nX2 = xScrn; 
    if (nY2 > yScrn) 
        nY2 = yScrn; 
    nWidth = nX2 - nX; 
    nHeight = nY2 - nY; 
    
    // 建立一個與屏幕設備描述表兼容的位圖 
    hBitmap = CreateCompatibleBitmap(hScrDC, nWidth, nHeight); 
    
    // 把新位圖選到內存設備描述表中 
    hOldBitmap = (HBITMAP)SelectObject(hMemDC, hBitmap); 
    
    // 把屏幕設備描述表拷貝到內存設備描述表中 
    BitBlt(hMemDC, 0, 0, nWidth, nHeight,hScrDC, nX, nY, SRCCOPY); 
    
    //獲得屏幕位圖的句柄 
    hBitmap =(HBITMAP)SelectObject(hMemDC, hOldBitmap); 
    
    //清除 
    DeleteDC(hScrDC); 
    DeleteDC(hMemDC); 
    
    // 返回位圖句柄 
    return hBitmap; 
}

BOOL CFeetScanView::SaveBitmapToFile(HBITMAP hBitmap, LPCTSTR lpFileName ) 
{ 
    HDC hDC; //設備描述表 
    int iBits; //當前顯示分辨率下每一個像素所佔字節數 
    WORD wBitCount; //位圖中每一個像素所佔字節數 
    DWORD dwPaletteSize=0, //定義調色板大小， 位圖中像素字節大小 ，位圖文件大小 ， 寫入文件字節數 
        dwBmBitsSize, 
        dwDIBSize, dwWritten; 
    BITMAP Bitmap; //位圖屬性結構 
    BITMAPFILEHEADER bmfHdr; //位圖文件頭結構 
    BITMAPINFOHEADER bi; //位圖信息頭結構 
    LPBITMAPINFOHEADER lpbi; //指向位圖信息頭結構 

    HANDLE fh, hDib, hPal,hOldPal=NULL; //定義文件，分配內存句柄，調色板句柄 

    //計算位圖文件每一個像素所佔字節數 
    HDC hWndDC = CreateDC("DISPLAY",NULL,NULL,NULL); 
    hDC = ::CreateCompatibleDC( hWndDC ) ; 
    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 if (iBits <= 24) 
        wBitCount = 24; 
    else 
        wBitCount = 24 ; 

    //計算調色板大小 
    if (wBitCount <= 8) 
        dwPaletteSize = (1 << wBitCount) * sizeof(RGBQUAD); 

    //設置位圖信息頭結構 
    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.biClrUsed = 0; 
    bi.biClrImportant = 0; 

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

    //爲位圖內容分配內存 
    hDib = GlobalAlloc(GHND,dwBmBitsSize+dwPaletteSize+sizeof(BITMAPINFOHEADER)); 
    lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDib); 
    *lpbi = bi; 

    // 處理調色板 
    hPal = GetStockObject(DEFAULT_PALETTE); 
    if (hPal) 
    { 
        hDC = ::GetDC(NULL); 
        hOldPal = ::SelectPalette(hDC, (HPALETTE)hPal, FALSE); 
        RealizePalette(hDC); 
    } 

    // 獲取該調色板下新的像素值 
    GetDIBits(hDC, hBitmap, 0, (UINT) Bitmap.bmHeight, 
        (LPSTR)lpbi + sizeof(BITMAPINFOHEADER) 
        +dwPaletteSize, 
        (LPBITMAPINFO ) 
        lpbi, DIB_RGB_COLORS); 

    //恢復調色板 
    if (hOldPal) 
    { 
        SelectPalette(hDC, (HPALETTE)hOldPal, TRUE); 
        RealizePalette(hDC); 
        ::ReleaseDC(NULL, hDC); 
    } 

    //建立位圖文件 
    fh = CreateFile(lpFileName, GENERIC_WRITE, 
        0, NULL, CREATE_ALWAYS, 
        FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN, NULL); 

    if (fh == INVALID_HANDLE_VALUE) 
        return FALSE; 

    // 設置位圖文件頭 
    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; 

    // 寫入位圖文件頭 
    WriteFile(fh, (LPSTR)&bmfHdr, sizeof(BITMAPFILEHEADER), &dwWritten, NULL); 

    // 寫入位圖文件其他內容 
    WriteFile(fh, (LPSTR)lpbi, dwDIBSize, 
        &dwWritten, NULL); 

    //清除 
    GlobalUnlock(hDib); 
    GlobalFree(hDib); 
    CloseHandle(fh); 

    return TRUE; 

}

//將當前的圖片進行90度顯示出來
    CDC* pDC1 = m_left_pic.GetDC();
    Graphics graph(pDC1->GetSafeHdc());
    CRect rect;
    m_left_pic.GetClientRect(rect);

    char szFileName[_MAX_PATH];
    char szPath[_MAX_PATH];
    GetConfigMgr()->GetModuleDirectory( szPath);
    sprintf( szFileName, "%s\\image.png", szPath);
    WCHAR wszWideString[_MAX_PATH];
    wcscpy(wszWideString, CT2CW(szFileName));
    Image image(wszWideString);

    REAL width  = (REAL)image.GetWidth();
    REAL height = (REAL)image.GetHeight();
    int nX = 0;
    int nY = 0;
    Point point90[] = {
        Point(nX + height,nY),
        Point(nX + height,nY+width),
        Point(nX,nY)
    };

    graph.DrawImage(&image, point90,3);
    ReleaseDC(pDC1);