C / C++ / MFC

/************************************************************************
Function : Screenshot
Parameter: hwnd			the window handle.
	   lpRect		the window rect.
return   : HBITMAP
other    : NULL
************************************************************************/
HBITMAP GetWindowBitmap(HWND hwnd, LPRECT lpRect)
{

     if( !lpRect )
          return NULL;

     HDC	hDC;
     HDC	hMemDC;
     HBITMAP	hBitmap = NULL;
     HBITMAP	hOldBitmap;
    
     if( hwnd == NULL )
         hDC = ::GetDC(HWND_DESKTOP);
     else
         hDC = ::GetWindowDC(hwnd);

     if( hDC == NULL )
         return NULL;

	 hMemDC  = CreateCompatibleDC(hDC);
     hBitmap = CreateCompatibleBitmap(hDC, lpRect->right - lpRect->left, 
	 lpRect->bottom - lpRect->top);

     if( hBitmap == NULL)
         return NULL;

     hOldBitmap = (HBITMAP)SelectObject(hMemDC, hBitmap);
     BitBlt(hMemDC, 0, 0, lpRect->right - lpRect->left, 
	 lpRect->bottom - lpRect->top, hDC, lpRect->left, lpRect->top, SRCCOPY);
    
     SelectObject(hMemDC, hOldBitmap);
     DeleteDC(hMemDC);
     ::ReleaseDC(hwnd, hDC);

     return hBitmap;
}

/************************************************************************
Function : Write to file
Parameter: strFilePath  the whole file path.
	   hBitmap	the bitmap memory
return   : if success return TRUE, otherwise return FALSE.
************************************************************************/
BOOL SaveBitmapToFile(CString strFilePath,HBITMAP hBitmap)
{
	HDC			hdc  = NULL;
	FILE*			fp   = NULL;
	LPVOID			pBuf = NULL;
	BITMAPINFO		bmpInfo;
	BITMAPFILEHEADER	bmpFileHeader;
	
	do{
		
		hdc = ::GetDC(NULL);
		ZeroMemory(&bmpInfo,sizeof(BITMAPINFO));
		bmpInfo.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);				
		GetDIBits(hdc,hBitmap,0,0,NULL,&bmpInfo,DIB_RGB_COLORS);
		//bmpInfo.bmiHeader.biBitCount = 0x08;		// 8bit,when I use it ,bmp is invalid.
		bmpInfo.bmiHeader.biBitCount = 0x10;		// 16

		if(bmpInfo.bmiHeader.biSizeImage <= 0)
			bmpInfo.bmiHeader.biSizeImage = bmpInfo.bmiHeader.biWidth*abs(bmpInfo.bmiHeader.biHeight)*(bmpInfo.bmiHeader.biBitCount+7)/8;
		
		if((pBuf = malloc(bmpInfo.bmiHeader.biSizeImage)) == NULL)
		{
			::MessageBox(NULL,_T("Unable to Allocate Bitmap Memory"),_T("Error"),MB_OK|MB_ICONERROR);
			return FALSE;
		}
		
		bmpInfo.bmiHeader.biCompression = BI_RGB;
		GetDIBits(hdc,hBitmap,0,bmpInfo.bmiHeader.biHeight,pBuf,&bmpInfo,DIB_RGB_COLORS);	
		
		TRACE(_T("%s\r\n"),strFilePath);
		if((fp=fopen(strFilePath.GetBuffer(strFilePath.GetLength()),"wb"))==NULL)
		{
			::MessageBox(NULL,_T("Unable to Create Bitmap File"),_T("Error"),MB_OK|MB_ICONERROR);
			return FALSE;
		}
		
		bmpFileHeader.bfReserved1	= 0;
		bmpFileHeader.bfReserved2	= 0;
		bmpFileHeader.bfSize		= sizeof(BITMAPFILEHEADER)+sizeof(BITMAPINFOHEADER)+bmpInfo.bmiHeader.biSizeImage;
		bmpFileHeader.bfType		= 'MB';
		bmpFileHeader.bfOffBits		= sizeof(BITMAPFILEHEADER)+sizeof(BITMAPINFOHEADER);
		
		fwrite(&bmpFileHeader,sizeof(BITMAPFILEHEADER),1,fp);
		fwrite(&bmpInfo.bmiHeader,sizeof(BITMAPINFOHEADER),1,fp);
		fwrite(pBuf,bmpInfo.bmiHeader.biSizeImage,1,fp);
		
	}while(false);
	
	if(hdc)
           ::ReleaseDC(NULL,hdc);
	
	if(pBuf)
           free(pBuf);
	
	if(fp)
           fclose(fp);
    
	return TRUE;
}<pre>



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