Overriding the default lasso behavior

'This works in partnership with the ButtonClicked event. The state of the button determines whether the field value is inserted or not.

Private Sub ValidationForm_AfterViewerLassoDrawn(ByVal pXDoc As CASCADELib.CscXDocument, ByVal PageIndex As Long, ByVal pField As CASCADELib.CscXDocField, ByVal TopPos As Long, ByVal LeftPos As Long, ByVal Width As Long, ByVal Height As Long, ByRef bCancel As Boolean)
    Dim img As CscImage
    'Get displayed image
    img = pXDoc.CDoc.Pages.ItemByIndex(PageIndex).GetImage
    Dim sSavedImage As String

    Select Case pField.Name
        Case "Crop"
            If m_crop Then
            'Call the function that saves the selected lasso area and return the file name
               Dim bSaved As Boolean
               sSavedImage = CropImage(img, LeftPos, TopPos, Width, Height, bSaved)
               'If the cropped area is sucessfully saved update the field
               If bSaved = True Then
                   'Set the correct field coordinates so that the MiniViewer shows the same snippet as the saved one:
                   pField.Width = Width
                   pField.Top = TopPos
                   pField.Left = LeftPos
                   pField.Height = Height
                   pField.PageIndex = PageIndex
                   'Set the field value to the filename containing the snippet and set it to valid
                   pField.Text = sSavedImage
                   pField.Valid = True
                   bCancel = True
               End If
               m_crop = False
           End If
    End Select

End Sub

Private Function CropImage(ByVal img As CscImage, ByVal LeftPos As Integer, ByVal TopPos As Integer, ByVal Width As Integer, ByVal Height As Integer, ByRef bSaved) As String
    On Error GoTo Err

    Dim snippet As New CscImage
    snippet.CreateImage(CscImgColFormatBinary, Width, Height, img.XResolution, img.YResolution)
    snippet.CopyRect(img, LeftPos, TopPos, 0, 0, Width, Height)

    Dim sFilename As String
    sFilename = "C:\Snippet\snippet.tif"

    snippet.Save(sFilename, CscImgFileFormatTIFFFaxG4)

    bSaved = True

    CropImage = sFilename
    Exit Function

Err:

    bSaved = False

End Function