This is a great component!
Looking at the code, and a local example I ran, it looks like the calculation in onResult determining whether or not the text has been truncated is based on the container after truncation instead of before. It seems that this would cause the onResult to callback with RESULT.NOT_TRUNCATED instead of RESULT.TRUNCATED. I may be reading / using it wrong.
If this is the case, maybe setting a truncated flag in the truncated() method, and passing that to onResult may be a feasible solution.