This article was written to our CTO, Carlo Vigiani, for iCoder magazine

One of the great improvements in all iPad owners lifestyle is the possibility to bring everywhere any sort of magazine or book, thanks to the screen size and the device light weight which both facilitate reading and carrying. In particular reports demonstrated that in a printed publications decreasing market there is a huge increase in the number of subscriptions to the digital versions of the same product (the interested reader can read this report from MPA: http://www.magazine.org/association/press/mpa_press_releases/mag-mobile-reader-study.aspx)

Apple is following this trend with great interest, and this is quite clear if we take a look at the evolution of the iOS features that have been introduced since the release of the version dedicated to iPad, that is 3.2.
In the particular the milestones that have been reached are three, shared between three major releas es of the operating system:

•     iOS 3.2 was enriched by the CoreText framework, a technology dedicated to rendering text on display available since long time on Mac OSX and  never ported in the earlier versions of the iPhone OS.

•     iOS 4.x introduced the concept of auto-renewable subscriptions, as an addition to standard non consumable In App Purchases; this feature has been introduced after long discussions between Apple, that applies the 30% commission on every In App sale and forbids any other external cheaper store access within its devices, and the publishers looking for customer fidelity techniques.

•     finally iOS 5.0 added the Newsstand feature, which provides a central place to collect all magazine and newspaper apps and at the same time provide night-time content push to all subscribers, letting them to immediately read the latest issues of their publications and saving them for the extra time (sometimes long) required for the download.

What Apple didn’t provide instead is a common and unique developer platform dedicated to the creation of apps dedicated to the magazine consumption. This lead to a lot of initiatives dedicated to help publishers to enter in the iPad market with their own magazines. These initiatives were taken by major and well known companies, such Adobe with its Digital Publishing business, and a lot of many start-
ups, everyone with its own solution.

As I said, Apple doesn’t provide a unique solution, but developers have the availability of a set of frameworks and techniques, with different levels of complexity, that provide different way of representing the page on the screen.

There is not an optimal choice, as the final decision needs to take care of aspects that go beyond pure technical considerations.
In this article we will try to depict these solutions mainly from the app developer point of view, but will never forget to enumerate the pro and cons that can affect the publisher decision on which technology to adopt.

Page rendering overview
We assume that you, the developer, are in a certain point of your app development where the magazine has been purchased, downloaded and it’s ready to be read. Your document data at this point is safely stored in the device file system and it can be represented by a single pdf file, or a collection of html and css files or a directory containing assets of different formats, such as images, videos, html5 widgets, text files. You’re now facing the problem of taking one page (which can extend beyond the screen boundaries) and presenting it in the empty space of your UIView dedicated to the
page rendering.

In the next post I will present the following methodologies to achieve this result:

•     pdf document rendering
•     pre-rendered image display
•     free format CoreText rendering
•     web based approach

01/2012 – source: www.icodermag.com