How iPhone-only Apps Appear on iPad

Introduction

As most iOS developers are hopefully aware, so-called “iPhone-only” apps can also be run on iPad. The app thinks it is running on an iPhone and appears with an iPhone-like screen size and aspect ratio. For most iPads, and for most iOS versions, this is the equivalent of a 3.5" iPhone 4/4S appearance (320×480 points), centred in the middle of the screen.

iPhone-only build of Adaptivity running on 9.7" iPad simulator running iOS 10

Other iPad Sizes

When the 12.9" iPad Pro was introduced things changed slightly. It has a much larger 2048×2732 pixel screen. Instead of simulating the 3.5" iPhone size, iPhone-only apps running on the 12.9" iPad Pro behave as if they are running on a 4.7" iPhone (375×667 points). The status bar is still cropped. As before, the actual size the screen is shown uses an integral zoom factor to avoid scaling artefacts: 750×1294 pixels or 1500×2588 pixels.

iPhone-only build of Adaptivity running on 2nd generation 12.9" iPad simulator running iOS 10
iPhone-only build of Adaptivity running on 10.5" iPad simulator running iOS 10

iOS 12

When iOS 12 arrived many things changed:

  • The status bar is no longer cropped from the app’s screen, but appears empty. The real status bar remains at the top of the iPad screen.
  • The corners of the screen are rounded slightly.
  • The 1x/2x zoom button became more prominent and changed to an icon with outward- and inward-facing arrows to hint at expanding and contracting the screen.
  • When shown at the larger size, all iPad devices are using non-integral scaling factors which introduces some blurring.

9.7" iPad Pro Running iOS 12

The actual size on screen is 750×1334 pixels or 1102×1960 pixels. The latter is a 1102 / 375 ≈ 2.94 scaling factor.

iPhone-only build of Adaptivity running on 9.7" iPad simulator running iOS 12

10.5" iPad Pro Running iOS 12

The actual size on screen is 750×1134 pixels or 1200×2136 pixels. The latter is a 1200 / 375 = 3.2 scaling factor.

iPhone-only build of Adaptivity running on 10.5" iPad simulator running iOS 12

1st and 2nd Generation 12.9" iPad Pro Running iOS 12

The actual size on screen is 750×1334 pixels or 1486×2644 pixels. The latter is a 1486 / 375 ≈ 3.96 scaling factor.

iPhone-only build of Adaptivity running on 2nd generation 12.9" iPad simulator running iOS 12

11" iPad Pro Running iOS 12

The actual size on screen is 750×1134 pixels or 1294×2300 pixels. The latter is a 1294 / 375 ≈ 3.45 scaling factor.

iPhone-only build of Adaptivity running on 11" iPad simulator running iOS 12

3rd Generation 12.9" iPad Pro Running iOS 12

The actual size on screen is 750×1134 pixels or 1486×2644 pixels. The latter is a 1486 / 375 ≈ 3.96 scaling factor. This is the same as the 1st and 2nd generation 12.9" iPad Pro running iOS 12.

iPhone-only build of Adaptivity running on 3rd generation 12.9" iPad simulator running iOS 12

Why Does any of this Matter?

It matters because the 3.5" iPhone 2:3 aspect ratio is hard to design for which can be quite a support burden in a world largely consisting of 9:16 or 9:19.5 aspect ratio iPhones.

Abandoning the 3.5" iPhone Size

The iPhone 4S cannot run iOS 10 so you might think that requiring iOS 10 (or later) would prevent you having to handle that screen size ever again. That isn’t sufficient if your app is iPhone-only because you have to consider the iPad. To never have to worry about the 3.5" iPhone size you need to either:

  • require at least iOS 12.

Other Articles in this Series

Adaptivity iOS App

The screenshots in this article were taken from the iOS simulator running my Adaptivity (C) app which only supports iPhone.

Other Articles That You Might Like

I have also written about External Display Support on iOS and Working with Multiple Versions of Xcode. You may not have realised that there were iPad Navigation Bar and Toolbar Height Changes in iOS 12. You must certainly have noticed the View Controller Presentation Changes in iOS 13.

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Geoff Hackworth

Independent and freelance software developer for iPhone, iPad and Mac