Advanced MFC Programming

Chapter 12. Screen Capturing & Printing
(
)
{
pWnd->GetSafeHwnd() != GetSafeHwnd() &&
pWnd->GetSafeHwnd() != AfxGetApp()->m_pMainWnd->GetSafeHwnd()
if(pWnd->GetSafeHwnd() != m_hWnd)
{
if(m_rectSelect.IsRectEmpty() != TRUE)
{
dc.Rectangle(m_rectSelect);
}
pWnd->GetWindowRect(m_rectSelect);
dc.Rectangle(m_rectSelect);
m_hWnd=pWnd->GetSafeHwnd();
}
}
else
{
if(m_rectSelect.IsRectEmpty() != TRUE)
{
dc.Rectangle(m_rectSelect);
m_rectSelect=CRect(0, 0, 0, 0);
}
m_hWnd=NULL;
}
if(bErase == TRUE && m_rectSelect.IsRectEmpty() != TRUE)
{
dc.Rectangle(m_rectSelect);
m_rectSelect=CRect(0, 0, 0, 0);
}
}
}
dc.SetROP2(nRop2Mode);
dc.SelectClipRgn(NULL);
New Command
After the user picks up a window, the dialog box will be closed. So we need to store the handle of
selected window (Contained in CSelDlg::m_hWnd) so that it can be used when making snapshot. In the
sample, variable CGDIDoc::m_hWnd is declared for this purpose. Also, function CGDIDoc::
GetSelectedWnd() is implemented to allow this handle be accessed from the view. In the sample, a new
command Capture | Settings is added to menu IDR_MAINFRAME, it is handled in function CGDIDoc::
OnCaptureSetting(). Within the function, window selection dialog box is implemented to let the user
select a window, if the user clicks OK button, the selected window’s handle will be saved to variable
CGDIDoc::m_hWnd:
void CGDIDoc::OnCaptureSetting()
{
CSelDlg dlg;
}
if(dlg.DoModal() == IDOK)
{
m_hWnd=dlg.GetSelectedWnd();
}
In function CGDIView::Capture(), we need to first obtain handle CGDIDoc::m_hWnd from the
document, if it is not a valid window handle, we still capture the whole desktop screen. Otherwise we use
this handle to find out the rectangular area of the window and make the snapshot.
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