The Guidelines
Working with effective pixels
Being device agnostic, the UI of a UWP has to appear crisp at any combination of screen sizes and densities. For this reason, given the spectrum of device densities currently on the market, we devised a grid based on multiples of 4. The simple rule of snapping all UI elements to multiples of 4 allows designers to create freely, without having to compromise the quality of their output.
"Effective pixels enable you to focus on the actual perceived size of a UI element without having to worry about the pixel density or viewing distance of different devices. For example, when you design a 1'' by 1'' element, that element will appear to be approximately 1'' on all devices. On a very large screen with a high pixel density, the element might be 200 by 200 physical pixels, while on a smaller device like a phone, it might be 150 by 150 physical pixels."
Standard patterns
The next step in the process was to define standard UX patterns, which can be used by designers and developers to build their app. Think of them as a series of framework options that will solve for the most common use cases and enable you to focus on crafting your app rather than have to spend time figuring out UX mechanics. The Microsoft team was responsible for identifying these patterns and we were in charge of putting them to use.