How to get trace area size from virtual keyboard handwriting view

[rrr_rrr_rrr1]

Hello everyone!

I am trying to get trace area size from virtual keyboard handwriting view
At the moment I can get pointer to the item of the TraceInputArea but it contains buttons (right and bottom).
I have tryed to get the first element from __traceCanvasList (TraceInputArea component) but the list is empty.

May be I am on wrong way and some more clear ways are exist.