Server Item OnGetExtent()

Objective Views User's Guide
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15.8 Server Item OnGetExtent()

The container must be able to query the server for the size of the item. The COleServerItem::OnGetExtent() method is called when the container requests the size of the item. The size of the item is always expressed in MM_HIMETRIC units (0.01 millimeters per logic unit). The viewport contains a method to return its bounds in MM_HIMETRIC units. All you need to do is get the viewport, make sure it is sized to display the entire model, and then retrieve the size.

Example 26: OnGetExtent() method

BOOL CMyAppSrvrItem::OnGetExtent(DVASPECT dwDrawAspect, 
                                 CSize& rSize)
{
  // Most applications, like this one, only handle drawing the
  // content aspect of the item.  If you wish to support other
  // aspects, such as DVASPECT_THUMBNAIL (by overriding OnDrawEx),
  // then this implementation of OnGetExtent should be modified
  // to handle the additional aspect(s).

  if (dwDrawAspect != DVASPECT_CONTENT)
    return COleServerItem::OnGetExtent(dwDrawAspect, rSize);

  //
  // This function is called to get the extent in HIMETRIC units of
  // the entire item.
  //
  CMyAppViewport* pViewport = GetViewport();
  if (pViewport != NULL)
  {
    // Set the viewport size 
    pViewport->SizeToModel();
    CRect rcBounds = pViewport->GetHiMetricBounds();
    rSize.cx = rcBounds.Width();
    rSize.cy = rcBounds.Height();
    return TRUE;
  }

  return FALSE;
}

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