bool   ImageUtil :: CreateGdiplusBmpFromHBITMAP_Alpha (  HBITMAP   hBmp ,  Gdiplus :: Bitmap **  bmp  )
{
     BITMAP   bitmap ;
     GetObject ( hBmp ,  sizeof ( BITMAP ), & bitmap );
     if ( bitmap . bmBitsPixel  != 32)
    {
         return   false ;
    }
     Gdiplus :: Bitmap *  pWrapBitmap  =  Gdiplus :: Bitmap :: FromHBITMAP ( hBmp ,  NULL );
     if  ( pWrapBitmap )
    {
         Gdiplus :: BitmapData   bitmapData ;
         Gdiplus :: Rect   rcImage (0, 0,  pWrapBitmap -> GetWidth (),  pWrapBitmap -> GetHeight ());
         pWrapBitmap -> LockBits (& rcImage ,  Gdiplus :: ImageLockModeRead ,  pWrapBitmap -> GetPixelFormat (), & bitmapData );
        * bmp  =  new   Gdiplus :: Bitmap ( bitmapData . Width ,  bitmapData . Height ,  bitmapData . Stride ,  PixelFormat32bppARGB , ( BYTE *) bitmapData . Scan0 );
         pWrapBitmap -> UnlockBits (& bitmapData );
         delete   pWrapBitmap ;
         return   true ;
    }
     return   false ; 
}

Gdiplus :: Bitmap *  ImageUtil :: CreateBitmapFromHBITMAP ( IN   HBITMAP   hBitmap )  
{  
     BITMAP   bmp  = { 0 };  
     if  ( 0 ==  GetObject ( hBitmap ,  sizeof ( BITMAP ), ( LPVOID )& bmp ) )  
    {  
         return   FALSE ;  
    }  
     // Although we can get bitmap data address by bmp.bmBits member of BITMAP   
     // which is got by GetObject function sometime,  
     // we can determine the bitmap data in the HBITMAP is arranged bottom-up   
     // or top-down, so we should always use GetDIBits to get bitmap data.  
     BYTE  * piexlsSrc  =  NULL ;  
     LONG   cbSize  =  bmp . bmWidthBytes  *  bmp . bmHeight ;  
     piexlsSrc  =  new   BYTE [ cbSize ];  
     BITMAPINFO   bmpInfo  = { 0 };  
     // We should initialize the first six members of BITMAPINFOHEADER structure.  
     // A bottom-up DIB is specified by setting the height to a positive number,   
     // while a top-down DIB is specified by setting the height to a negative number.  
     bmpInfo . bmiHeader . biSize  =  sizeof ( BITMAPINFOHEADER );  
     bmpInfo . bmiHeader . biWidth  =  bmp . bmWidth ;  
     bmpInfo . bmiHeader . biHeight  =  bmp . bmHeight ;  // 正数，说明数据从下到上，如未负数，则从上到下 
     bmpInfo . bmiHeader . biPlanes  =  bmp . bmPlanes ;  
     bmpInfo . bmiHeader . biBitCount  =  bmp . bmBitsPixel ;  
     bmpInfo . bmiHeader . biCompression  =  BI_RGB ;  
     HDC   hdcScreen  =  CreateDC ( L "DISPLAY" ,  NULL ,  NULL , NULL );  
     LONG   cbCopied  =  GetDIBits ( hdcScreen ,  hBitmap , 0,  bmp . bmHeight ,   
         piexlsSrc , & bmpInfo ,  DIB_RGB_COLORS );  
     DeleteDC ( hdcScreen );  
     if  ( 0 ==  cbCopied  )  
    {  
         delete  []  piexlsSrc ;  
         return   FALSE ;  
    }  
     // Create an GDI+ Bitmap has the same dimensions with hbitmap  
     Bitmap  * pBitmap  =  new   Bitmap ( bmp . bmWidth ,  bmp . bmHeight ,  PixelFormat32bppPARGB );  
     // Access to the Gdiplus::Bitmap's pixel data  
     BitmapData   bitmapData ;  
     Rect   rect (0, 0,  bmp . bmWidth ,  bmp . bmHeight );  
     if  (  Ok  !=  pBitmap -> LockBits (& rect ,  ImageLockModeRead ,   
         PixelFormat32bppPARGB , & bitmapData ) )  
    {  
         delete  ( pBitmap );  
         return   NULL ;  
    }  
     BYTE  * pixelsDest  = ( BYTE *) bitmapData . Scan0 ;  
     int   nLinesize  =  bmp . bmWidth  *  sizeof ( UINT );  
     int   nHeight  =  bmp . bmHeight ;  
     // Copy pixel data from HBITMAP by bottom-up.  
     for  (  int   y  = 0;  y  <  nHeight ;  y ++ )  
    {  
         // 从下到上复制数据，因为前面设置高度时是正数。 
         memcpy_s (   
            ( pixelsDest  +  y  *  nLinesize ),   
             nLinesize ,   
            ( piexlsSrc  + ( nHeight  -  y  - 1) *  nLinesize ),   
             nLinesize );  
    }  
     // Copy the data in temporary buffer to pBitmap  
     if  (  Ok  !=  pBitmap -> UnlockBits (& bitmapData ) )  
    {  
         delete   pBitmap ;  
    }  
     delete  []  piexlsSrc ;  
     return   pBitmap ;  
}