1 February 2014Jason Prado, Quora:
In our push for polish we had a goal of never dropping a frame on high-end devices, and we mostly achieved that goal. The engineering complexity here is finding a way to fully utilize the multicore architecture of newer iPhones on top of the UIKit framework which has no support for multithreading. Significant work went into creating a framework for doing rendering work on multiple threads, and we spent a long time finding the balance between performance and complexity. Turning synchronous operations into asynchronous ones adds a lot of cognitive overhead, and this was one of the biggest challenges of the project.
Even if the app turns out to be a massive flop, you have to admire the the engineering talent here. Prado says that Paper is one of Facebook’s longest running projects. They truly doubled down on this — somehow managing to overcome Facebook’s ‘ship quickly’ culture.