Using the tablet app

The tablet app, like the phone app, allows you to specify the default orientation for your app. However, there are some additional options in terms of sizing the canvas:

Here, you can set up your app for specific devices, some of which are named Surface Pro, iPad, and so on, but you also have the ability to define your own height and width. This gives you the flexibility to target devices that are explicitly supported by your organization, or if you are going to work to a specific design.

You also get the same Advanced settings options so that you can lock the aspect ratio and orientation, just like you did within the phone canvas.