Zappdesigntemplates "expanding circle" transition iOS

Wanted to recreate the effect that I saw on @Anton Aheichanka page with iOS' custom transitions. Well, not the perfect one yet, can be optimised a bit but it was pretty simple and easy to recreate in iOS. I thought it would be harder a bit.

If you are interested in the project, you can find the tutorial here. Written in Swift.

I also recreated his shrinking button effect (shrink to a circle, shows a loading indicator) but that is saved for another project. :)