Beyond practical matters of text flow and keyboard size, you can also use landscape orientation to provide a completely different view of your app. Stock and financial apps, for example, commonly display summary info in portrait view but bloom into graphical charts when you turn them on their side. Weightbot takes a similar approach, showing your weight for an individual day in portrait orientation, but revealing a cascade of stats and charts when you switch to landscape. In fact, Weightbot shows different charts depending on which way you turn the device. In all of these examples, the landscape view is used to give enhanced context to the snapshot shown in portrait orientation. This use of landscape orientation gives users a way to focus the app and review the content in a more immersive way. As you saw a few pages ago, landscape orientation typically signals increased attention from the user, an opportunity to draw them into the interface. Here, the effect is further enhanced by removing controls and providing a rich visualization to explore.
Figure 9-4. Turn Weightbot on its left side (top) to see stats and a progress bar toward your goal; flip it to its right side (bottom) to see a line graph of your weight over time.
With this approach, you're doing more than just flipping the interface on its side; you're throwing it out and replacing it with a completely new one. In geekspeak, you're changing modes, the kind of switcheroo you might see if you select a new tab in your app's tab bar. Landscape modes often sport graphic-laden interfaces, an appropriate choice given the common association with gee-whiz media thanks to landscape's frequent use in games and video. The built-in iPod app and the Stanza ebook reader, for example, both go from staid text-based lists in portrait orientation to a glossy view of album and book covers in landscape view. Similarly, note-taking app Evernote transforms from a text-oriented list view of notes to a denser image-based view in landscape orientation. In all of these examples, it's the same content, but a very different presentation.
Figure 9-5. Evernote's portrait view (left) offers a thumbnail image with a text description of each note. The landscape view (right) drops the text to offer a dense ribbon of images to browse.
A word of caution about this approach: many will never discover the gorgeous graphical alternative you've tucked around the corner of this 90-degree tilt. If your app works just fine in portrait mode (and of course it does), it won't even occur to some people to try it in landscape— even avid, day-in-day-out users. I met a poker fan who played the Texas Hold 'Em app for months before he realized that he could get a bird's eye view of the table—and a much faster game—if he played in landscape.
Like a gesture, screen rotation is invisible. Without visual cues or explicit instructions, these landscape modes can easily remain hidden treasures. That's especially true for Weightbot's approach of showing a different chart depending on which way you turn for the landscape view. It's a novel approach that saves interface chrome, but you can bet lots of people find one chart but never discover the other. Some landscapes simply go unvisited. Plan for that contingency by making sure that any features or info that you show in landscape orientation can also be discovered—albeit in different form—in portrait orientation, too.