' ------------------------ StartAnnotations --------------------------
''' <summary>
'''   Enables annotations and displays all that are viewable.</summary>
Private Sub StartAnnotations()
    ' If there is no AnnotationService yet, create one.
    If _annotService Is Nothing Then
        ' docViewer is a document viewing control named in Window1.xaml.
        _annotService = New AnnotationService(docViewer)
    End If

    ' If the AnnotationService is currently enabled, disable it.
    If _annotService.IsEnabled = True Then
        _annotService.Disable()
    End If

    ' Open a stream to the file for storing annotations.
    _annotStream = New FileStream(_annotStorePath, FileMode.OpenOrCreate, FileAccess.ReadWrite)

    ' Create an AnnotationStore using the file stream.
    _annotStore = New XmlStreamStore(_annotStream)

    ' Enable the AnnotationService using the new store.
    _annotService.Enable(_annotStore)
End Sub


' ------------------------ StopAnnotations ---------------------------
''' <summary>
'''   Disables annotation processing and hides all annotations.</summary>
Private Sub StopAnnotations()
    ' If the AnnotationStore is active, flush and close it.
    If _annotStore IsNot Nothing Then
        _annotStore.Flush()
        _annotStream.Flush()
        _annotStream.Close()
        _annotStore = Nothing
    End If

    ' If the AnnotationService is active, shut it down.
    If _annotService IsNot Nothing Then
        If _annotService.IsEnabled Then
            _annotService.Disable() ' Disable the AnnotationService.
            _annotService = Nothing
        End If
    End If
End Sub