Swipe direction for read document on iPad

Question

Is there any recommendation about the direction of swipe for an app that allow user to read PDF documents? I mean if I have to chose is better the up/down or the left/right swipe?

In my own experience I prefer apps that allow me to swipe up and down to go through the document's pages. This is because sometime is more comfortable to scroll the document e watch the last part of the previous page while i'm reading the current page, this happens usually when the previous sentence / paragraph is cross pages. On the other side well crafted app like iBook allow only the horizontal swipe gesture.

It will be great if you will able to cite some research about this topic

Edit: On 23 October 2012 Apple introduce iBooks 3 which brings as new feature the continuos vertical scroll. I think this is relevant to the scope of this question.

Answer 1

Have you seen this article?

I think it depends on content. A series of things that fit on a single page (e.g. a photo album) is served better with side swiping. So are things like a book of text, because we're used to reading a page at a time, we're used to being on a page and sometimes organizing in pages helps understanding.

But there's not much of a negative for vertical scrolling, it can better accomodate different kinds of content, has less limitations and doesn't require the extra content producing work of organizing into pages.

I say when in doubt go with vertical scrolling.

Answer 2

Here's a bit of justification for both ways:

• Up/down is how PDFs work on computer screens, such as in Adobe Acrobat and Adobe Reader. The next page appears below the current page. If the flow of text is continous, then this would make reading more efficient since a user can continually scroll down for more lines, rather than having to flip to the next page and reposition their focus from the bottom right corner back to the top left. However, if the entire next page is loaded when scrolling down, then that point is irrelevant.

• Left/right makes sense for ebooks since the swiping action is very similar to turning a page in a physical book. In PDFs with a lot of pages, it will also help retain a reader's focus as they complete one page at a time and they are not bombarded with a long constant stream of text.

For me, the choice between these depends on what I'm reading. Longer materials, like books, would best utilize left/right navigation, since I think it's easier to take one page at a time and it mimics the page-turning action. For shorter PDFs, delivering the information continuously cuts down on wasted readjustments of a reader's focus.

However, for the general case where the PDFs can have varying amounts of content, and assuming both swipes would load the whole next page, it comes down to which swiping direction is more efficient. I couldn't find any data from studies on this, but in my opinion, left/right swiping has become widely recognized for turning pages on a mobile device.