Adjusting zoom in Android app


I have made a prototype for a small screen (approx 5x9cm) and I want to use my phone as a mockup for testing this prototype. However, when opening the prototype in the app, it is zoomed in to fill the screen, making it far larger than necessary, and also leaving some of the content off-screen. Is there a way to change this setting? Real size, or just zoom to fit would be better.