Hello, bravo for the initiative. As user of iPhone, iPad, PCs, cannot use your app.
It is Limited to 50/60 Hz mains power transformers?
IOS app?
Web app?
"Transformers - Alfonso Martignoni " (Italinan?Brazilian?) is focused on mains power transformers.
Many better texts exist that cover the entire field , see Hunt static electromagnetic devices and Magnetic components by Steve Smith
Nowadays most mains freq power trsf are readily avail commodities from many vendors.
The need is in high freq SMPS trsf for power and bridge drivers.
We used Intusoft Magnetic Designer for decades, fine PC app, covers most practical trsf designs.
Bon chance
Jon