By default all Universal Windows Apps support Continuum for Phones, but Microsoft has included a number of APIs which let developers optimize their app for the usage scenario.
When apps go from the big screen to the small screen or vice versa for example the apps are sent an event allowing develops to rejig their elements, optimize their user interface for touch or keyboard or even create multi-screen experiences.
Microsoft is also allowing developers to opt out of supporting Continuum for Phones if they feel their app is not quite ready.
Microsoft recommends developers include different scaling assets to support big screens, and interestingly these assets are only downloaded and installed of devices connect to a big screen, and are deleted if they are not used in 30 days, suggesting apps may actually look better the second time they are used on a big screen vs the first time.
To developers Microsoft recommends the following:
- Use responsive techniques to ensure your app reflows beautifully to any screen. Targeting the universal device family will benefit you most on Continuum and across all Windows devices.
- Remember that users will most likely interact with your app on the connected display with keyboard and mouse. Consider implementing and testing UI optimized for keyboard and mouse if your app is primarily touch-driven.
- Include additional scaling assets in your app package to make your app pixel perfect on any display. Most screens a user might connect to will be scale-100 or scale-150.
- Leverage multi-screen APIs to create rich, interactive, robust multi-screen experiences.
Read the full article with all the detail here.