Q127192

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page	Q127192: HOWTO: Draw Controls in an OLE Metafile	/kb/127/Q127192/

Q127192: HOWTO: Draw Controls in an OLE Metafile

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Article: Q127192
Product(s): Microsoft C Compiler
Version(s): winnt:2.0,2.1,4.0,4.1,5.0
Operating System(s): 
Keyword(s): kbole kbnokeyword kbActiveX kbCOMt kbCtrl kbInplaceAct kbMetafile kbMFC kbVC150 kbVC200
Last Modified: 06-MAY-2001

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The information in this article applies to:

- The Microsoft Foundation Classes (MFC), used with:
   - Microsoft Visual C++ for Windows, 16-bit edition, versions 1.5, 1.51, 1.52 
   - Microsoft Visual C++, 32-bit Editions, versions 2.0, 2.1, 4.0, 4.1 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 5.0 
   - Microsoft Visual C++, 32-bit Professional Edition, version 5.0 
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SUMMARY
=======

You can use controls, either directly on a CView or from a dialog template on a
CFormView, in an OLE enabled MFC application. However, when the item is embedded
but not active, the controls on these views will not be drawn to the Windows
metafile supplied to the COleServerItem::OnDraw() function. In this case, you
must "draw" the controls manually into the metafile. This article shows you how.

MORE INFORMATION
================

The simplest way to get controls to "draw" in a metafile is to use the same
method the VIEWEX sample uses to draw its CInputView to a printer device
context. VIEWEX's OnPrint routine draws each control as a rectangle, circle,
text, and so on. Override the COleServerItem::OnDraw() function and insert your
code into it. As an example, use the COleServerItem::OnDraw() function listed in
this article; it shows both the VIEWEX code to insert in the OnDraw member
function and the helper function PaintChildWindows() that actually does the
painting of each control.

Sample Code
-----------

  /* Compile options needed: Standard
  */ 

  void CMyServerItem::OnDraw(CDC* pDC) // pDC is actually a metafile
  {
      //BLOCK: Set up scale mode
      {
          CClientDC dcScreen(NULL);
          pDC->SetMapMode(MM_ANISOTROPIC);
          // map 1 screen logical inch to 1 printer (/output) logical inch
          pDC->SetWindowExt(dcScreen.GetDeviceCaps(LOGPIXELSX),
                  dcScreen.GetDeviceCaps(LOGPIXELSX));
          pDC->SetViewportExt(pDC->GetDeviceCaps(LOGPIXELSX),
                  pDC->GetDeviceCaps(LOGPIXELSX));
      }
      // we must also offset the window positions relative to the scroll
      // offset

      // We cheat here since some controls do not paint if they are
      // invisible, so we temporary make set the appropriate visible bits
      // during preview mode so the controls think they are visible even
      // though they aren't.

      HWND hWndCheatVisible = NULL;
      if (!IsWindowVisible())
      {
          // walk up to the top until we find the invisible window
          for (HWND hWnd = m_hWnd;
              hWnd != NULL; hWnd = ::GetParent(hWnd))
          {
              ASSERT(hWnd != NULL);
              DWORD dwStyle = ::GetWindowLong(hWnd, GWL_STYLE);
              if ((dwStyle & WS_VISIBLE) == 0)
              {
                  ::SetWindowLong(hWnd, GWL_STYLE, dwStyle | WS_VISIBLE);
                  hWndCheatVisible = hWnd;
                  break;
              }
          }
          ASSERT(hWndCheatVisible != NULL);
      }

      CPen pen(PS_SOLID, 1, RGB(0,0,0));  // solid black pen
      CPen* pOldPen = pDC->SelectObject(&pen);

      ASSERT(pDC->GetWindowOrg() == CPoint(0,0));
      CRect pRect = new CRect(-50,-50,600,600);

      PaintChildWindows(m_hWnd, pDC, GetDeviceScrollPosition());
      ASSERT(pDC->GetWindowOrg() == CPoint(0,0));
      pDC->SelectObject(pOldPen);

      if (hWndCheatVisible != NULL)
          ::SetWindowLong(hWndCheatVisible, GWL_STYLE,
              ::GetWindowLong(hWndCheatVisible, GWL_STYLE) &~ WS_VISIBLE);
  }

  void CMyServerItem::PaintChildWindows(HWND hWndParent,
                                        CDC* pDC, CPoint ptOffset)
  {
      for (HWND hWndChild = ::GetTopWindow(hWndParent);
          hWndChild != NULL;
          hWndChild = ::GetNextWindow(hWndChild, GW_HWNDNEXT))
      {
          CRect rect;
          ::GetWindowRect(hWndChild, rect);  // wnd rect in screen coords
          ScreenToClient(&rect);             // relative to this view

          HDC hdcOut = pDC->m_hDC;
  #ifdef _DEBUG
          CPoint pt = pDC->GetWindowOrg();
          ASSERT(pt.x == 0 && pt.y == 0);
  #endif

          DWORD dwStyle = ::GetWindowLong(hWndChild, GWL_STYLE);
          if (dwStyle & (WS_HSCROLL|WS_VSCROLL))
          {
              TRACE("Warning: printing control with scrollbars not
   supported\n");
          }
          if (dwStyle & WS_BORDER)
          {
              // the only case we special case - manually drawn border
              ::Rectangle(hdcOut, rect.left, rect.top, rect.right,
                          rect.bottom);
              rect.InflateRect(-1,-1);        // 1 logical pixel
          }

          pDC->SaveDC();
          {
              CPoint pt(ptOffset.x + rect.left, ptOffset.y + rect.top);
              pDC->LPtoDP(&pt);
              pDC->OffsetViewportOrg(pt.x, pt.y);
                  // set the viewport origin so that the window origin
                  //  can be changed by the control

              // draw it using a non-virtual HDC
              ::SendMessage(hWndChild, WM_PAINT, (WPARAM)hdcOut, 0L);
          }
          pDC->RestoreDC(-1);

          if (::GetTopWindow(hWndChild) != NULL)
              PaintChildWindows(hWndChild, pDC, ptOffset);
      }
  }

Additional query words: mfc ole inplace embed

======================================================================
Keywords          : kbole kbnokeyword kbActiveX kbCOMt kbCtrl kbInplaceAct kbMetafile kbMFC kbVC150 kbVC200 kbVC400 kbVC500 kbGrpDSMFCATL 
Technology        : kbAudDeveloper kbMFC
Version           : winnt:2.0,2.1,4.0,4.1,5.0
Hardware          : x86
Issue type        : kbhowto

=============================================================================

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