Thx, I found the function and it indeed looked very easy...
I couldn't find the code for FitStart.
In the ImageView a couple of fitTypes are dealt with straight away, but the implementation of FitStart is native (to my understanding).
Therefor I couldn't find it...
The Matrix is also not accepted straight away, and I don't know how to map it to Matrix4...
But I understand that official support is comming later 🙂