Annotations with a fixed ratio

[Winfried]

I would like to have annotations with a fixed ratio, for example 3:2 or 3:4 16:9
So far there is one with 1:1 and a rectangle one, but this rectangle one has no fixed ratio.
To mark how to crop an images this might be usefull. Just set the visibility to 10 or 20% and I can mark
how to crop the photo.

Winfried