Apple in iOS 13 and macOS Catalina introduced Project Catalyst, designed to allow iOS developers to port their iPad apps over to the Mac with little effort, making it simpler for developers to design cross-platform apps.
Ars Technica recently spoke with some of the Apple team members responsible for creating and promoting Project Catalyst, and it's worth a read for those who are interested in the feature.
Apple decided to allow developers to port iPad apps instead of iPhone apps because it's a "more natural transition" bringing an app from an iPad to a Mac due to the closer display sizes. From Todd Benjamin, Apple's senior director of marketing for macOS:
Just design-wise, the difference between an iPad app and an iPhone app is that the iPad app has gone through a design iteration to take advantage of more screen space. And as you bring that app over to the Mac... you have something that's designed around that space that you can work with and that you can start from.
Ali Ozer, Apple's cocoa engineering manager, also said that choosing the iPad pre-empts user concerns about mobile ports spilling over to the desktop. "This is one way of making developers aware that an iPhone app in its current form might not be the right design," said Ozer.
Developers who have already used Project Catalyst have been able to port iPad versions of Twitter, TripIt, and Asphalt 9: Legends to the Mac. The developers that have worked with Project Catalyst told Ars that it was, on the whole, simple to use and "able to just work," as one Twitter developer said.
As for quality concerns, Apple's Catalyst team expects public reviews to be a major factor when it comes to ensuring Mac apps offer a rich, Mac-like experience. From Shaan Pruden, Apple's senior director of partner management and developer relations:
"Then we come down to customers' reaction and ratings and all of that kind of stuff. Which hopefully will drive the right behavior for a developer, which is to do the work and do it right and don't be lazy."
The full deep dive into Project Catalyst can be read over on the Ars Technica website, and it goes into detail on just how Project Catalyst functions, what developers think of the feature thus far, and it shares Apple's thoughts on SwiftUI.
Top Rated Comments
But if that's the app you want, a developer could make an iPadOS variant of the app that does nothing but take the iPhone version of the app to the iPad, compile it for the Mac, disable resizing and set the window to be like an iPhone and release it as a Mac app without an iPad variant. It's a few hoops, but it's still an easy process.
This was definitely made as a conscious decision, and a good one at that. Furthermore, this will bring more iPhone-only apps to the iPad too likely.
With so much consideration needed to make an app look/feel at home on that many screen sizes and input methods, you might as well go back to writing native iOS and Mac apps. Otherwise, we're just going to get stuck with a glut of "Mac" apps that look extremely out-of-place. It's going to be the Mac platform that suffers from Catalyst. Separating the wheat from the chaff is about to get a lot more difficult.