[vtkusers] vtk zoom indicator

[K O ranjith]

I'm using vtk for developing a MRI DICOM Image viewer in Qt.
The viewer uses vtkDICOMImageReader,  vtkImageViewer2 & QVTKWidget.
I need to show a zoom indicator line which varies length with zoom value
and need not affect other operation like rotate, pan( which is used for
DICOM image in same window). It's position should be fixed at side of
viewer and should not alter with zoom, pan, rotate.
I added an line as an vtkactor  to the renderer using vtkLineSource.
 Its length altering  with zoom as I intended, but problem is its position
also altering with the zoom, also rotate and Pan affecting on it.
How can I make the position of the line fixed at side of the viewer.
Have any option in vtk for visual indication of zoom factor something like
vtkOrientationMarkerWidget for orientation...
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://public.kitware.com/pipermail/vtkusers/attachments/20170623/da87d717/attachment.html>