VC++ to achieve output GIF form and display GIF animation method

This article tells about VC++ in the form of the display of GIF animation method, this is the main part of the code, in this code, VC++ will use GDI technology to load GIF images, define GUID array, define Pointers, initialize the member variables, release property objects, release GUID and other resources.

The code is as follows:

//Load GIF file
void COutputGIFDlg::OnBrowse()
{
 CFileDialog flDlg(TRUE, "", "", OFN_HIDEREADONLY | OFN_OVERWRITEPROMPT,
   "GIF|*.gif;||");//The definition file opens dialog box
 if (flDlg.DoModal() == IDOK)
 {
 CString szText;
 szText = flDlg.GetPathName();
 m_FileName.SetWindowText(szText);
 m_pBmp = Bitmap::FromFile(szText.AllocSysString()); //Load GIF image
 szText.ReleaseBuffer();
 m_nCount = m_pBmp->GetFrameDimensionsCount(); //Gets the frame dimension
 GUID *pGuids = new GUID[m_nCount]; //Define an array of guids
 m_pBmp->GetFrameDimensionsList(pGuids,m_nCount); //Gets the GUID of the image frame
 m_FrameCount = m_pBmp->GetFrameCount(pGuids); //Gets the number of GIF frames
 UINT nSize; //Define an integer variable
 m_nCount = 0; //Initializes a member variable
 m_pBmp->GetPropertySize(&nSize, &m_nDelay); //Get property size
 PropertyItem *pItem = NULL; //Define property pointer
 pItem = (PropertyItem*)malloc(nSize); //Allocate the appropriate space for the property pointer
 m_pBmp->GetAllPropertyItems(nSize, m_nDelay, pItem);//Get attribute information
 m_nDelay = ((long*)pItem->value)[0]; //Gets the delay of the first frame
 free(pItem); //Release property object
 delete [] pGuids; //Release the GUID
 m_nIndex = 0; //Initializes a member variable
 KillTimer(1);
 SetTimer(1, 300, NULL);
 }
}
void COutputGIFDlg::OnTimer(UINT nIDEvent)
{
 GUID Guid = FrameDimensionTime; //Define a GUID
 CDC* pDC = GetDC(); //Gets the device context of the window
 //Define a memory canvas
 CMemDC dc(pDC, CRect(20, 50, m_pBmp->GetWidth()+20, m_pBmp->GetHeight()+50));
 Graphics gh(dc.m_hDC); //Define an image object
 //Draws an image to the device context
 gh.DrawImage(m_pBmp, 0, 0, m_pBmp->GetWidth(), m_pBmp->GetHeight());
 m_pBmp->SelectActiveFrame(&Guid, m_nIndex++);//Set the next frame
 if(m_nIndex == m_FrameCount) //Determines whether the current frame is a tail frame
  m_nIndex = 0; //Sets the current frame to frame 1
 CDialog::OnTimer(nIDEvent);
}
void COutputGIFDlg::OnCancel()
{
 if (m_pBmp != NULL)
 {
 delete m_pBmp;
 m_pBmp = NULL;
 }
 CDialog::OnCancel();
}