The U.S. Patent and Trademark Office granted Apple's U.S. Patent No. 8,335,986 for "Previewing different types of documents," which describes the basic functionality of the current Preview app.
According to the patent's abstract, the property covers a "previewing application" for displaying a plurality of documents simultaneously in a single window, with the content appearing as digital books. Users can view pages in one or two dimensions and search through all opened document for specified keywords which are then displayed in an ordered fashion.
While the language calls for a slightly different user interface and tweaked usability function when compared to the existing Preview app, the patent outlines the underlying operational features that serve as a basis for the current standard OS X software. Specifically, the current iteration of Preview does not display manuals or PDF files as "books," but the application does include powerful content search tools that arrange pages according to the '986 patent.
Search tool view in patent (top) shows highlighted text in-window, Preview (bottom) uses column to arrange results.
The invention is basically a software-agnostic document reader that displays content in a managed format easily digestible by the user. Key to the property is the ability to search within the document, with results also displayed in a logical manner, which in this case only shows pages containing the keyword.
Both the patent and the current Preview app use a sidebar column that displays opened documents or pages within an opened document. This space also displays pages in which a search term is present either by page number or a ranking heirarchy.
Column view as seen in patent (top) and Preview (bottom).
In place of the two-dimensional book format detailed in the patent, Preview uses a multitouch-enabled view akin to "Coverflow," the UI first introduced with iTunes and the iPod touch. The latest Mac OS X 10.8 Mountain Lion operating system allows for full-screen viewing and multitouch page navigation. Preview is the default document viewer in OS X unless otherwise specified by the user.
The '986 patent was first applied for in 2009 and credits Conrad Carlen, Patrick Coffman, Ryan Staake and Matthew Sarnoff as its inventors.