C / C++ / MFC

#define RGB 3
for(int iLine = 0; iLine < 480; iLine++)
{
	for(int iElement = 0; iElement < 640 * RGB; iElement++)
	{
		m_pBuffer[iLine * 640 * RGB + iElement] = pHdr->lpData[iLine * 640 * RGB + iElement];
	}
}

#define RGB 3
for(int iLine = 0; iLine < 200; iLine++)
{
	for(int iElement = 0; iElement < 300 * RGB; iElement++)
	{
	        m_pBuffer[iLine * 300 * RGB + iElement] = pHdr->lpData[iLine * 640 * RGB + iElement];
	}
}

void CDlg::OnLButtonUp(UINT nFlags, CPoint point)
{
	m_AreaRect.SetRect(m_RectStart.x,m_RectStart.y,point.x,point.y);
			
	// set begin point, endpoint  and offsetpoint
	CPoint Begin,End, Offset;
		
	// beginpoint according to client coordinates
	Begin.SetPoint(m_AreaRect.TopLeft().x,m_AreaRect.TopLeft().y);
		
	// endpoint accordng to client coordinates
	End.SetPoint(m_AreaRect.BottomRight().x,m_AreaRect.BottomRight().y);

	// offset is begin of livevideowindow topleft position
	Offset.SetPoint(m_LivePosition.TopLeft().x,m_LivePosition.TopLeft().y);

	Begin -= Offset;
	End   -= Offset;

	m_RectWithOffset.SetRect(Begin.x,Begin.y,End.x,End.y);		

	Width  = m_RectWithOffset.Width();
        Height = m_RectWithOffset.Height();

	m_MarkBitmapinfo.bmiHeader.biBitCount = 24;
	m_MarkBitmapinfo.bmiHeader.biWidth = Width;
	m_MarkBitmapinfo.bmiHeader.biHeight = Height;
	m_MarkBitmapinfo.bmiHeader.biPlanes = 1;
	m_MarkBitmapinfo.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
	m_MarkBitmapinfo.bmiHeader.biSizeImage = Width * Height * 3;		m_MarkBitmapinfo.bmiHeader.biCompression = BI_RGB;

	CClientDC dc(this);
	m_HBitmapMark = CreateDDBFromPixel(dc.m_hDC,Width,Height,24,NULL);

        m_ImgProc.CopyData(Begin,End);
}

CreateDDBFromPixel( HDC hDC, UINT uWidth, UINT uHeight, UINT uBitsPerPixel, LPVOID pBits )
{
	  HBITMAP HBitmap = NULL;

      if ( !uWidth || !uHeight || !uBitsPerPixel )
	  {
         return HBitmap;
	  }
      
	  LONG lBmpSize = uWidth * uHeight * uBitsPerPixel / 8;	  
	  BITMAPINFO bmpInfo = { 0 };
      bmpInfo.bmiHeader.biBitCount = uBitsPerPixel;
      bmpInfo.bmiHeader.biHeight = uHeight;
      bmpInfo.bmiHeader.biWidth = uWidth;
      bmpInfo.bmiHeader.biPlanes = 1;
	  bmpInfo.bmiHeader.biSizeImage = uWidth * uHeight * (uBitsPerPixel / 8);
      bmpInfo.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
	  bmpInfo.bmiHeader.biCompression = BI_RGB;

      // Pointer to access the pixels of bitmap       
	  UINT * pPixels = NULL;	  
      	  	  
	  HBitmap = CreateDIBitmap(hDC,(BITMAPINFOHEADER*)&bmpInfo.bmiHeader,//CBM_INIT
				0,pBits,(BITMAPINFO*)&bmpInfo,DIB_RGB_COLORS);

      if (!HBitmap)
	  {
          return HBitmap;//hBitmap; // return if invalid bitmaps
	  }

      return HBitmap;
}