Scaling issue when replaying metafile

I am trying to replay a metafile that has been saved on the disk. It works except for one thing. I cannot figure out how to get a proper scaling. If I don't do anything, when drawing the bitmap on the screen from the metafile, it appears much, much bigger than it should. Well, given that the window size is 100*100, it never exceeds that on the screen, but it means only a small part of a much bigger bitmap is visible.

Here is a code sample that reproduces the problem.

Code:

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void CreateMetafile()
{
        CString strFileName = "c:\\test\\test.emf";

        CMetaFileDC memDC;
        CRect rect (0, 0, 100, 100);
        memDC.CreateEnhanced(&memDC, strFileName, rect, "just a test");

        CBrush m_brush(RGB(255,255,255));
        CPen m_pen(PS_SOLID, 1, COLORREF(RGB(0, 255, 0)));
        memDC.SelectObject(&m_brush);
        memDC.SelectObject(&m_pen);

        memDC.SetBkMode(TRANSPARENT);
        memDC.Rectangle(0,0,rect.Width(),rect.Height());
        memDC.MoveTo(0, 0);
        memDC.LineTo(100, 100);

        HENHMETAFILE hmf = memDC.CloseEnhanced();
        DeleteEnhMetaFile(hmf);
}

void ReplayMetafile()
{
        CWnd wnd;
        CRect rect (100, 100, 200, 200);
        wnd.CreateEx(NULL, NULL, NULL,WS_POPUP |  WS_CHILD | WS_CLIPSIBLINGS, rect, NULL, NULL, NULL);

        hmf = GetEnhMetaFile(strFileName);
        CRect rectWnd = rect;
        CPoint ptToolTipLeft = rectWnd.TopLeft();
        SetWindowPos(wnd.m_hWnd, HWND_TOPMOST,ptToolTipLeft.x+1, ptToolTipLeft.y+1, rectWnd.Width(), rectWnd.Height(),SWP_SHOWWINDOW|SWP_NOOWNERZORDER|SWP_NOACTIVATE);

        CClientDC paintdc(&wnd);

        int ratio = 1;
        paintdc.SetMapMode(MM_ANISOTROPIC);
        paintdc.SetWindowExt(100*ratio, 100*ratio);
        paintdc.SetViewportExt(100, 100);


        CRect rect1 (0, 0, 100, 100);
        paintdc.PlayMetaFile(hmf, rect1);

        DeleteEnhMetaFile(hmf);
        AfxMessageBox("close");
}

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I am trying to calculate this ratio that would display a proper 100*100 pixels bitmap on the screen.

I have tried to play with different mappings, including by applying mappings to the metafile. On my PC at least, the correct ratio would be around 39, but using a hard coded value is not satisfactory as it does not give the same result on someone else's PC.